WO2019107115A1 - Method for eluting calcium from steel-making slag, method for collecting calcium from steel-making slag, and device for eluting calcium from steel-making slag - Google Patents
Method for eluting calcium from steel-making slag, method for collecting calcium from steel-making slag, and device for eluting calcium from steel-making slag Download PDFInfo
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- WO2019107115A1 WO2019107115A1 PCT/JP2018/041632 JP2018041632W WO2019107115A1 WO 2019107115 A1 WO2019107115 A1 WO 2019107115A1 JP 2018041632 W JP2018041632 W JP 2018041632W WO 2019107115 A1 WO2019107115 A1 WO 2019107115A1
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- WO
- WIPO (PCT)
- Prior art keywords
- steelmaking slag
- calcium
- grinding
- slurry
- carbon dioxide
- Prior art date
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- 239000002893 slag Substances 0.000 title claims abstract description 457
- 238000009628 steelmaking Methods 0.000 title claims abstract description 371
- 239000011575 calcium Substances 0.000 title claims abstract description 318
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 title claims abstract description 240
- 229910052791 calcium Inorganic materials 0.000 title claims abstract description 240
- 238000000034 method Methods 0.000 title claims abstract description 104
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 claims abstract description 310
- 229910002092 carbon dioxide Inorganic materials 0.000 claims abstract description 155
- 239000001569 carbon dioxide Substances 0.000 claims abstract description 154
- 239000002002 slurry Substances 0.000 claims abstract description 126
- 239000007864 aqueous solution Substances 0.000 claims abstract description 125
- 238000003756 stirring Methods 0.000 claims abstract description 123
- 239000007788 liquid Substances 0.000 claims abstract description 34
- 238000010298 pulverizing process Methods 0.000 claims abstract description 29
- 238000000227 grinding Methods 0.000 claims description 139
- 230000007246 mechanism Effects 0.000 claims description 54
- 230000008569 process Effects 0.000 claims description 15
- 229910000831 Steel Inorganic materials 0.000 claims description 10
- 239000010959 steel Substances 0.000 claims description 10
- 238000004062 sedimentation Methods 0.000 claims description 7
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 121
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 115
- 238000006703 hydration reaction Methods 0.000 description 99
- 230000036571 hydration Effects 0.000 description 97
- 239000002245 particle Substances 0.000 description 86
- 238000010828 elution Methods 0.000 description 62
- 229910052742 iron Inorganic materials 0.000 description 53
- 238000007885 magnetic separation Methods 0.000 description 50
- 150000001875 compounds Chemical class 0.000 description 45
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 36
- 239000007789 gas Substances 0.000 description 35
- 238000011084 recovery Methods 0.000 description 30
- 230000001965 increasing effect Effects 0.000 description 29
- 238000007654 immersion Methods 0.000 description 28
- 229910052698 phosphorus Inorganic materials 0.000 description 24
- 239000007787 solid Substances 0.000 description 23
- 239000000243 solution Substances 0.000 description 21
- 235000010216 calcium carbonate Nutrition 0.000 description 20
- 239000011574 phosphorus Substances 0.000 description 20
- 235000012241 calcium silicate Nutrition 0.000 description 18
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 description 17
- 239000000378 calcium silicate Substances 0.000 description 17
- 229910052918 calcium silicate Inorganic materials 0.000 description 17
- OYACROKNLOSFPA-UHFFFAOYSA-N calcium;dioxido(oxo)silane Chemical compound [Ca+2].[O-][Si]([O-])=O OYACROKNLOSFPA-UHFFFAOYSA-N 0.000 description 17
- 230000005291 magnetic effect Effects 0.000 description 17
- 239000000126 substance Substances 0.000 description 17
- 229910000019 calcium carbonate Inorganic materials 0.000 description 15
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 14
- HDYBUJBCJPAOLV-UHFFFAOYSA-N [O-2].[Fe+2].[Ca+2].[Al+3] Chemical compound [O-2].[Fe+2].[Ca+2].[Al+3] HDYBUJBCJPAOLV-UHFFFAOYSA-N 0.000 description 14
- 239000002244 precipitate Substances 0.000 description 14
- 238000012360 testing method Methods 0.000 description 14
- 239000000920 calcium hydroxide Substances 0.000 description 13
- 229910001861 calcium hydroxide Inorganic materials 0.000 description 13
- -1 calcium iron aluminum Chemical compound 0.000 description 13
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 12
- 239000002253 acid Substances 0.000 description 12
- 238000010438 heat treatment Methods 0.000 description 12
- 238000000926 separation method Methods 0.000 description 12
- ODINCKMPIJJUCX-UHFFFAOYSA-N Calcium oxide Chemical compound [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 description 11
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 10
- 239000003570 air Substances 0.000 description 10
- 229910052782 aluminium Inorganic materials 0.000 description 10
- 230000007423 decrease Effects 0.000 description 10
- 239000011572 manganese Substances 0.000 description 10
- 239000000463 material Substances 0.000 description 10
- 229910052710 silicon Inorganic materials 0.000 description 10
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 9
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 9
- 235000011941 Tilia x europaea Nutrition 0.000 description 9
- BRPQOXSCLDDYGP-UHFFFAOYSA-N calcium oxide Chemical compound [O-2].[Ca+2] BRPQOXSCLDDYGP-UHFFFAOYSA-N 0.000 description 9
- 238000006243 chemical reaction Methods 0.000 description 9
- 230000000694 effects Effects 0.000 description 9
- 239000004571 lime Substances 0.000 description 9
- 229910052748 manganese Inorganic materials 0.000 description 9
- 239000000292 calcium oxide Substances 0.000 description 8
- 229940087373 calcium oxide Drugs 0.000 description 8
- 238000001556 precipitation Methods 0.000 description 8
- 230000002708 enhancing effect Effects 0.000 description 7
- 238000002386 leaching Methods 0.000 description 7
- 239000006148 magnetic separator Substances 0.000 description 7
- 238000012545 processing Methods 0.000 description 7
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 6
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 6
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 6
- 229910000020 calcium bicarbonate Inorganic materials 0.000 description 6
- 238000002474 experimental method Methods 0.000 description 6
- 229910052500 inorganic mineral Inorganic materials 0.000 description 6
- 235000010755 mineral Nutrition 0.000 description 6
- 239000011707 mineral Substances 0.000 description 6
- 239000010703 silicon Substances 0.000 description 6
- 238000005406 washing Methods 0.000 description 6
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 5
- BVJRIMBTLVPCFB-UHFFFAOYSA-N [Fe+2].[O-2].[Ca+2].[O-2] Chemical compound [Fe+2].[O-2].[Ca+2].[O-2] BVJRIMBTLVPCFB-UHFFFAOYSA-N 0.000 description 5
- 229910021529 ammonia Inorganic materials 0.000 description 5
- NKWPZUCBCARRDP-UHFFFAOYSA-L calcium bicarbonate Chemical compound [Ca+2].OC([O-])=O.OC([O-])=O NKWPZUCBCARRDP-UHFFFAOYSA-L 0.000 description 5
- 238000004090 dissolution Methods 0.000 description 5
- 238000007670 refining Methods 0.000 description 5
- 238000009751 slip forming Methods 0.000 description 5
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 4
- 239000011651 chromium Substances 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 230000004907 flux Effects 0.000 description 4
- SZVJSHCCFOBDDC-UHFFFAOYSA-N iron(II,III) oxide Inorganic materials O=[Fe]O[Fe]O[Fe]=O SZVJSHCCFOBDDC-UHFFFAOYSA-N 0.000 description 4
- 239000006228 supernatant Substances 0.000 description 4
- 239000010936 titanium Substances 0.000 description 4
- 239000002699 waste material Substances 0.000 description 4
- BVKZGUZCCUSVTD-UHFFFAOYSA-M Bicarbonate Chemical compound OC([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-M 0.000 description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 3
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 3
- 229910004283 SiO 4 Inorganic materials 0.000 description 3
- 238000004458 analytical method Methods 0.000 description 3
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 3
- 229940043430 calcium compound Drugs 0.000 description 3
- 150000001674 calcium compounds Chemical class 0.000 description 3
- 229910052799 carbon Inorganic materials 0.000 description 3
- BVKZGUZCCUSVTD-UHFFFAOYSA-N carbonic acid Chemical compound OC(O)=O BVKZGUZCCUSVTD-UHFFFAOYSA-N 0.000 description 3
- 150000004649 carbonic acid derivatives Chemical class 0.000 description 3
- 238000009614 chemical analysis method Methods 0.000 description 3
- 239000003795 chemical substances by application Substances 0.000 description 3
- 229910052804 chromium Inorganic materials 0.000 description 3
- 238000005260 corrosion Methods 0.000 description 3
- 230000007797 corrosion Effects 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 238000001914 filtration Methods 0.000 description 3
- 239000012530 fluid Substances 0.000 description 3
- 150000004677 hydrates Chemical class 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 3
- 150000004679 hydroxides Chemical class 0.000 description 3
- 229910001872 inorganic gas Inorganic materials 0.000 description 3
- 150000002500 ions Chemical class 0.000 description 3
- 239000011777 magnesium Substances 0.000 description 3
- 229910052757 nitrogen Inorganic materials 0.000 description 3
- 239000001301 oxygen Substances 0.000 description 3
- 229910052760 oxygen Inorganic materials 0.000 description 3
- 230000035515 penetration Effects 0.000 description 3
- 230000002093 peripheral effect Effects 0.000 description 3
- 239000012466 permeate Substances 0.000 description 3
- 239000002994 raw material Substances 0.000 description 3
- 230000009257 reactivity Effects 0.000 description 3
- 150000003839 salts Chemical class 0.000 description 3
- 229910052717 sulfur Inorganic materials 0.000 description 3
- 229910052719 titanium Inorganic materials 0.000 description 3
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 2
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- 239000005997 Calcium carbide Substances 0.000 description 2
- BHPQYMZQTOCNFJ-UHFFFAOYSA-N Calcium cation Chemical compound [Ca+2] BHPQYMZQTOCNFJ-UHFFFAOYSA-N 0.000 description 2
- KZBUYRJDOAKODT-UHFFFAOYSA-N Chlorine Chemical compound ClCl KZBUYRJDOAKODT-UHFFFAOYSA-N 0.000 description 2
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N Propane Chemical compound CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 description 2
- 229910004298 SiO 2 Inorganic materials 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- RAHZWNYVWXNFOC-UHFFFAOYSA-N Sulphur dioxide Chemical compound O=S=O RAHZWNYVWXNFOC-UHFFFAOYSA-N 0.000 description 2
- 230000002378 acidificating effect Effects 0.000 description 2
- 238000013019 agitation Methods 0.000 description 2
- HSFWRNGVRCDJHI-UHFFFAOYSA-N alpha-acetylene Natural products C#C HSFWRNGVRCDJHI-UHFFFAOYSA-N 0.000 description 2
- KCZFLPPCFOHPNI-UHFFFAOYSA-N alumane;iron Chemical compound [AlH3].[Fe] KCZFLPPCFOHPNI-UHFFFAOYSA-N 0.000 description 2
- 239000011324 bead Substances 0.000 description 2
- 238000007664 blowing Methods 0.000 description 2
- 229910001424 calcium ion Inorganic materials 0.000 description 2
- 238000004364 calculation method Methods 0.000 description 2
- 239000004568 cement Substances 0.000 description 2
- 238000002485 combustion reaction Methods 0.000 description 2
- 238000004891 communication Methods 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 230000006837 decompression Effects 0.000 description 2
- 238000007599 discharging Methods 0.000 description 2
- 125000002534 ethynyl group Chemical group [H]C#C* 0.000 description 2
- 229910052595 hematite Inorganic materials 0.000 description 2
- 239000011019 hematite Substances 0.000 description 2
- 239000008235 industrial water Substances 0.000 description 2
- 230000005764 inhibitory process Effects 0.000 description 2
- LIKBJVNGSGBSGK-UHFFFAOYSA-N iron(3+);oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[Fe+3].[Fe+3] LIKBJVNGSGBSGK-UHFFFAOYSA-N 0.000 description 2
- 229910052749 magnesium Inorganic materials 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 2
- 230000003472 neutralizing effect Effects 0.000 description 2
- 230000001376 precipitating effect Effects 0.000 description 2
- 238000011085 pressure filtration Methods 0.000 description 2
- 230000000630 rising effect Effects 0.000 description 2
- 238000004904 shortening Methods 0.000 description 2
- 238000005245 sintering Methods 0.000 description 2
- 238000007711 solidification Methods 0.000 description 2
- 230000008023 solidification Effects 0.000 description 2
- CLZWAWBPWVRRGI-UHFFFAOYSA-N tert-butyl 2-[2-[2-[2-[bis[2-[(2-methylpropan-2-yl)oxy]-2-oxoethyl]amino]-5-bromophenoxy]ethoxy]-4-methyl-n-[2-[(2-methylpropan-2-yl)oxy]-2-oxoethyl]anilino]acetate Chemical compound CC1=CC=C(N(CC(=O)OC(C)(C)C)CC(=O)OC(C)(C)C)C(OCCOC=2C(=CC=C(Br)C=2)N(CC(=O)OC(C)(C)C)CC(=O)OC(C)(C)C)=C1 CLZWAWBPWVRRGI-UHFFFAOYSA-N 0.000 description 2
- 238000003828 vacuum filtration Methods 0.000 description 2
- 239000002351 wastewater Substances 0.000 description 2
- 238000004065 wastewater treatment Methods 0.000 description 2
- 238000001238 wet grinding Methods 0.000 description 2
- UXVMQQNJUSDDNG-UHFFFAOYSA-L Calcium chloride Chemical compound [Cl-].[Cl-].[Ca+2] UXVMQQNJUSDDNG-UHFFFAOYSA-L 0.000 description 1
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- OTMSDBZUPAUEDD-UHFFFAOYSA-N Ethane Chemical compound CC OTMSDBZUPAUEDD-UHFFFAOYSA-N 0.000 description 1
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 1
- 239000005977 Ethylene Substances 0.000 description 1
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- 238000005411 Van der Waals force Methods 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 238000005273 aeration Methods 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 238000009739 binding Methods 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 230000005587 bubbling Effects 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 239000001110 calcium chloride Substances 0.000 description 1
- 229910001628 calcium chloride Inorganic materials 0.000 description 1
- VMLAJPONBZSGBD-UHFFFAOYSA-L calcium;hydrogen carbonate;hydroxide Chemical compound [OH-].[Ca+2].OC([O-])=O VMLAJPONBZSGBD-UHFFFAOYSA-L 0.000 description 1
- 229910002091 carbon monoxide Inorganic materials 0.000 description 1
- 238000009833 condensation Methods 0.000 description 1
- 230000005494 condensation Effects 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000005536 corrosion prevention Methods 0.000 description 1
- 238000004132 cross linking Methods 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 238000005137 deposition process Methods 0.000 description 1
- 230000003009 desulfurizing effect Effects 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 230000008030 elimination Effects 0.000 description 1
- 238000003379 elimination reaction Methods 0.000 description 1
- 239000005447 environmental material Substances 0.000 description 1
- 238000004880 explosion Methods 0.000 description 1
- 230000005294 ferromagnetic effect Effects 0.000 description 1
- 239000003337 fertilizer Substances 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 239000001307 helium Substances 0.000 description 1
- 229910052734 helium Inorganic materials 0.000 description 1
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 125000004435 hydrogen atom Chemical class [H]* 0.000 description 1
- 238000004898 kneading Methods 0.000 description 1
- 230000005415 magnetization Effects 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 239000011259 mixed solution Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000003607 modifier Substances 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 150000003018 phosphorus compounds Chemical class 0.000 description 1
- 229940088417 precipitated calcium carbonate Drugs 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 239000001294 propane Substances 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 238000002407 reforming Methods 0.000 description 1
- 238000012552 review Methods 0.000 description 1
- 239000013535 sea water Substances 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 241000894007 species Species 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 239000011593 sulfur Substances 0.000 description 1
- 239000008399 tap water Substances 0.000 description 1
- 235000020679 tap water Nutrition 0.000 description 1
- 230000026683 transduction Effects 0.000 description 1
- 238000010361 transduction Methods 0.000 description 1
- 238000010792 warming Methods 0.000 description 1
- 239000003643 water by type Substances 0.000 description 1
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B09—DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
- B09B—DISPOSAL OF SOLID WASTE NOT OTHERWISE PROVIDED FOR
- B09B3/00—Destroying solid waste or transforming solid waste into something useful or harmless
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/20—Treatment of water, waste water, or sewage by degassing, i.e. liberation of dissolved gases
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B5/00—Treatment of metallurgical slag ; Artificial stone from molten metallurgical slag
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
Definitions
- the present invention relates to a method of eluting calcium from steelmaking slag, a method of recovering calcium from steelmaking slag, and an apparatus for eluting calcium from steelmaking slag.
- Steelmaking slag (such as converter slag, pretreated slag, secondary refining slag and electric furnace slag) generated in the steelmaking process is used in a wide range of applications including cement materials, road base materials for roads, civil engineering materials and fertilizers (non-patented) See documents 1 to 3).
- some steelmaking slags not used for the above applications are disposed of in landfills.
- steelmaking slag calcium (Ca), iron (Fe), silicon (Si), manganese (Mn), magnesium (Mg), aluminum (Al), phosphorus (P), titanium (Ti), chromium (Cr), It is known that elements such as sulfur (S) are contained.
- the element contained most in steelmaking slag is calcium used in large amounts in the steelmaking process, and usually Fe is next contained in a large amount.
- about 20% by mass to about 50% by mass is calcium, and about 1% by mass to about 30% by mass is Fe.
- the calcium in steelmaking slag is the reaction of free lime (CaO) and free lime (CaO) deposited in the solidification of steelmaking slag, as the raw lime (CaO) supplied in the steelmaking process remains or as it reacts with water vapor or carbon dioxide in the air.
- Ca 2 (Al 1 -x Fe x ) 2 O 5 calcium iron oxide (Ca 2 (Al 1 -x Fe x ) 2 O 5 ) or the like (hereinafter referred to collectively as "Ca compound, generically containing compounds containing the above-mentioned calcium present in steelmaking slag It is also called ").
- Calcium carbonate and calcium oxide are main slag forming materials in iron making process and steel making process in iron making process, and are used as a modifier of basicity and viscosity of the slag and as a dephosphorization agent from molten steel There is.
- calcium hydroxide obtained by watering calcium oxide is used as a neutralizing agent such as acid in a drainage process. Therefore, it is expected that the cost of steelmaking can be reduced if the Ca compound contained in the steelmaking slag is recovered and reused in the steelmaking process.
- Calcium in steelmaking slag can be recovered, for example, by eluting it in an acidic aqueous solution such as hydrochloric acid, nitric acid or sulfuric acid.
- an acidic aqueous solution such as hydrochloric acid, nitric acid or sulfuric acid.
- the salts of calcium and the acid formed in this method are difficult to reuse.
- calcium chloride produced by eluting calcium in steelmaking slag into hydrochloric acid can be reused if it is heated to form oxides, but there is a problem that the processing cost of harmful chlorine gas generated during the above heating is high .
- calcium in the steelmaking slag is eluted and recovered in an acidic aqueous solution, there is also a problem that the cost of purchasing the acid and discarding the acid after the elution process is high.
- Patent Document 1 describes a method of blowing carbon dioxide into an aqueous solution in which calcium in a converter slag is eluted, and recovering precipitated calcium carbonate. At this time, the lower limit value of pH is maintained at about 10 in order to suppress the formation of calcium hydrogen carbonate having high solubility in water. Although a specific method for maintaining the pH at 10 or more is not described in Patent Document 1, it is considered that the pH is maintained at 10 or more by adjusting the blowing amount of carbon dioxide.
- Patent Document 2 a crushed steelmaking slag is separated into an iron-enriched phase and a phosphorus-enriched phase, and the Ca compound in the phosphorus-enriched phase is dissolved in washing water in which carbon dioxide is dissolved, and then 50 to 60 washing waters.
- a method is disclosed in which calcium hydrogen carbonate in wash water is precipitated as calcium carbonate by heating to about ° C. and recovered.
- Patent Document 3 describes a method for separating and recovering a Ca compound in multiple steps from a steelmaking slag. In this method, it is described that by immersing steelmaking slag (pretreated slag) a plurality of times in water blown with carbon dioxide, the 2CaO ⁇ SiO 2 phase and phosphorus dissolved in this phase are preferentially eluted There is.
- Fe in steelmaking slag is present as iron-based oxide, calcium iron aluminum oxide, and metallic iron, although in a very small amount.
- the iron-based oxide contains not only Mn or Mg but also a small amount of elements such as Ca, Al, Si, P, Ti, Cr and S.
- calcium iron aluminum also contains a small amount of elements such as Si, P, Ti, Cr and S.
- the iron-based oxide also includes a compound in which a portion of the surface has been converted to a hydroxide or the like by water vapor in the air, and calcium iron aluminum oxide also contains water vapor and carbon dioxide in the air It also includes a compound in which part of its surface has been changed to hydroxide or carbonate by the
- iron-based oxides exist as wustite-based oxides (FeO), and also exist as hematite-based oxides (Fe 2 O 3 ) and magnetite-based oxides (Fe 3 O 4 ).
- wustite-based oxide and hematite-based oxide can be separated from steelmaking slag by magnetic separation because magnetite-based oxide (Fe 3 O 4 ), which is a ferromagnetic substance, is dispersed therein.
- magnetite-based oxides which are present alone or coexist with other iron-based oxides can also be separated from steelmaking slag by magnetic separation.
- Patent Documents 4 to 6 describe a method of reforming wustite-based oxides to magnetite-based oxides by oxidation treatment or the like in order to separate more iron-based oxides by magnetic separation.
- the calcium iron aluminum is magnetized to become a magnetic body, it can be separated from the steelmaking slag by magnetic separation as well.
- Iron-based oxides and calcium-iron-aluminum oxide (hereinafter collectively referred to as "iron-based compound”.
- Calcium-iron-aluminum oxide is a Ca compound and an iron-based compound at the same time.) Since the content is as small as 0.1% by mass or less, it can be used as a material for blast furnace and sintering if it is separated and recovered from steelmaking slag by the above-described magnetic separation and the like.
- the metallic iron is Fe which is caught in the slag in the steelmaking process, or fine Fe which precipitates out during solidification of the steelmaking slag. Large metallic iron is removed by magnetic separation or other methods in a dry process of crushing or crushing steelmaking slag in the atmosphere.
- this washing solution is mixed with a solution leached with mineral acid, and the solution leached with mineral acid is neutralized to precipitate calcium carbonate, the mixture is acidified with mineral acid to dissolve calcium in the aqueous solution.
- the amount (solubility) increases. Therefore, even if calcium carbonate precipitates, a large amount of calcium remains in the mixed solution, and the calcium recovery efficiency is degraded.
- Patent Literatures 1 and 2 do not suggest any device for increasing the elution amount of the Ca compound to the CO 2 aqueous solution. Further, in the method described in Patent Document 3, if the number of steps of dissolving the Ca compound is increased, it is considered that the total elution amount of calcium is also increased, but in this method, as described above, the steps become complicated and recovered. There is a problem that the cost becomes high.
- the present invention can easily elute more calcium from steelmaking slag from a steelmaking slag into CO 2 aqueous solution, can elute calcium from steelmaking slag and can elute calcium from the steelmaking slag It is an object of the present invention to provide an apparatus and a method of recovering calcium eluted by this method.
- the present invention suppresses the stirring of the slurry containing steelmaking slag in the region on the upper side close to the liquid surface inside the crushing and settling tank while settling the steelmaking slag, while suppressing the stirring of the steelmaking slag.
- the present invention also relates to a method for recovering calcium from steelmaking slag, which comprises the steps of eluting calcium from steelmaking slag by the above method, and recovering the eluted calcium.
- a grinding / settling tank into which a slurry containing steelmaking slag is charged, and an area on the bottom side inside the grinding / settling tank, and an upper portion close to a liquid surface inside the grinding / settling tank
- the present invention relates to an apparatus for eluting calcium from steelmaking slag, including a carbon dioxide introduction unit for introducing carbon dioxide into the slurry simultaneously with grinding or grinding by the grinding mechanism.
- the present invention it is possible to easily dissolve a large amount of calcium from steelmaking slag to a CO 2 aqueous solution, a method of eluting calcium from steelmaking slag, an apparatus capable of performing the method of eluting calcium from the steelmaking slag, Methods are provided for recovering eluted calcium.
- FIG. 1 is a schematic view showing the configuration of an apparatus used to elute calcium from steelmaking slag in the first embodiment of the present invention.
- FIG. 2A is a schematic view showing an exemplary form of a stirring impeller of a stirring mechanism of an apparatus used for eluting calcium from steelmaking slag
- FIG. 2B is a diagram of an apparatus used for eluting calcium from steelmaking slag It is a schematic diagram which shows the exemplary form of the stirring screw which a stirring mechanism has.
- FIG. 3 is a schematic view showing the configuration of another apparatus used to elute calcium from steelmaking slag in the first embodiment of the present invention.
- FIG. 1 is a schematic view showing the configuration of an apparatus used to elute calcium from steelmaking slag in the first embodiment of the present invention.
- FIG. 2A is a schematic view showing an exemplary form of a stirring impeller of a stirring mechanism of an apparatus used for eluting calcium from steelmaking slag
- FIG. 2B is a diagram
- FIG. 4 is a schematic view showing the configuration of still another apparatus used to elute calcium from steelmaking slag in the first embodiment of the present invention.
- FIG. 5 is a schematic view showing the configuration of still another apparatus used to elute calcium from steelmaking slag in the first embodiment of the present invention.
- FIG. 6 is a flow chart illustrating exemplary steps of a method of eluting calcium from steelmaking slag according to a second embodiment of the present invention.
- FIG. 7 is a flow chart illustrating exemplary steps of a method of eluting calcium from steelmaking slag according to a third embodiment of the present invention.
- FIG. 8 is a flow chart of a method of recovering calcium from steelmaking slag according to the present invention.
- FIG. 9 is a flow chart showing an example of the step of recovering calcium in the method of recovering calcium from steelmaking slag according to the present invention.
- FIG. 10 is a graph showing the relationship between the proportion of each carbonic acid species in the aqueous CO 2 solution and the pH.
- Pulverization refers to mechanically giving energy to target particles (particles of steelmaking slag) to break them and reducing their size.
- a method of mechanically applying energy there is a method of moving a grinding medium such as a ball and bringing it into contact with target particles, and a method of making parts of a device such as a roller and a hammer move and make contact with target particles. Simply flowing the particles of interest does not provide enough energy to destroy the particles of interest and reduce their size, as the particles of interest only move with the flow of the slurry.
- calcium in steelmaking slag is free lime, calcium hydroxide (Ca (OH) 2 ), calcium carbonate (CaCO 3 ), calcium silicate (Ca 2 SiO 4 , Ca 3 SiO 5 ) and calcium oxide It exists in a form such as iron aluminum (Ca 2 (Al 1 -x Fe x ) 2 O 5 ).
- free lime is easily dissolved in a CO 2 aqueous solution, it is usually contained in the steelmaking slag only at less than about 10% by mass.
- calcium silicate is generally contained in about 25% by mass to 70% by mass in steelmaking slag
- calcium iron aluminum is usually contained in about 2% by mass to about 30% by mass in steelmaking slag. Therefore, if the calcium contained in Ca compounds other than free lime (such as calcium silicates and calcium oxide iron aluminum) easily eluted with CO 2 aqueous solution, to increase the dissolution of calcium into CO 2 solution from steelmaking slag It is considered possible to recover calcium from steelmaking slag in a shorter time.
- calcium has high solubility in an aqueous solution of CO 2, but silicon, aluminum, iron and the like have low solubility in an aqueous solution of CO 2 . Therefore, when calcium silicate and calcium iron oxide dissolve in the aqueous solution of CO 2 , calcium elutes, but silicon, aluminum and iron etc. become hydroxide, carbonate or hydrate surface of steel slag May remain in the In addition, silicon, aluminum, iron and the like, which have low solubility in a CO 2 aqueous solution, may precipitate on the surface of steelmaking slag after being eluted once. In addition, iron and manganese contained in iron oxide and calcium iron oxide aluminum in steelmaking slag also have low solubility.
- iron oxide or calcium iron oxide aluminum elutes slightly in a CO 2 aqueous solution
- iron or manganese may be precipitated on the surface of steelmaking slag. It is thought that the elution rate of calcium is slower than the ideal state because these substances remaining or precipitated on the surface of the steelmaking slag prevent the contact between the CO 2 aqueous solution and the surface of the steelmaking slag.
- the elution of calcium from the steelmaking slag is caused by the contact of the Ca compound and water near or in the surface of the steelmaking slag.
- the amount of contact with water is larger in the vicinity of the surface. Therefore, calcium is more likely to be eluted near the surface of the steelmaking slag.
- the components contained in steelmaking slag are dissolved in the aqueous solution of CO 2 used for elution of calcium, as described above, silicon, aluminum, iron and manganese or their hydroxides, carbonates and hydrates etc. It may remain or precipitate on the surface of the slag. When these remaining or precipitated substances inhibit the penetration of the aqueous solution of CO 2 into the inside of the steelmaking slag, calcium is less likely to be eluted from the inside of the steelmaking slag.
- grinding the steelmaking slag forms a new surface on which the above substance has not yet remained or precipitated, and the CO 2 aqueous solution is allowed to permeate from the continuously formed surface to the inside of the steelmaking slag.
- the CO 2 aqueous solution is allowed to permeate from the continuously formed surface to the inside of the steelmaking slag.
- calcium can be easily eluted from the inside of the steelmaking slag.
- granular steelmaking slag hereinafter, also simply referred to as "slag particles” by crushing steelmaking slag etc.
- steelmaking slag it is crushed or crushed into slag particles and particles). This means that the surface area of CO 2 aqueous solution and slag particles can be made larger by increasing the surface area of both.
- the contact area between the CO 2 aqueous solution and the slag particles becomes larger, and the CO 2 aqueous solution is contained inside the slag particles. It becomes easy to penetrate.
- the grinding and the like can be efficiently performed in a state where the concentration of the steelmaking slag is high.
- grains in a slurry are easy to settle, so that a particle size is large. Therefore, in the method of the present embodiment, since the particle diameter is large, the surface area per volume is small, and the slag particles in which the elution of calcium from the surface and the penetration of the aqueous solution of CO 2 into the inside are difficult to occur are precipitated and crushed and crushed. It moves to the area on the bottom side of the tank, is crushed and the like, and contact with the CO 2 aqueous solution efficiently forms a new surface on which calcium is easily eluted. The slag particles whose particle size has become smaller due to pulverization and the like tend to float and move in the liquid surface direction (upper direction) of the pulverization / settling tank.
- the above-mentioned pulverization and the like are performed only in the area on the bottom side of the pulverization / settling tank. Therefore, in the area on the upper side of the crushing and settling tank, the stirring of the slurry is suppressed, and the flow rate of the slurry is significantly slower than the area on the bottom side. That is, in the area
- the concentration of steelmaking slag in the slurry becomes high (the concentration of water in the slurry becomes low) in the region on the bottom side of the crushing and settling tank, or the precipitated steelmaking slag accumulates in the region on the bottom side.
- crushing etc. is performed in the area
- the flow velocity of the slurry in the region on the bottom side where crushing of steelmaking slag is performed, it is preferable to set the flow velocity of the slurry to 1 m / min or more and 100 m / min or less, in order to efficiently crush steelmaking slag having a high concentration. It is more preferable to set at least 70 min / min.
- the flow velocity of the slurry in the upper region where steelmaking slag is allowed to settle, is preferably 20 m / min or less, more preferably 10 m / min or less.
- the lower limit of the flow velocity of the slurry in the upper side region is not particularly limited, it can be 0 m / min (static state).
- the area on the upper side where crushing or the like of steelmaking slag is not performed preferably has a height of 0.2 m or more, and more preferably 0.3 m or more Preferably, it is more preferably 0.6 m or more.
- the upper limit of the height of the upper region is not particularly limited, but may be 50.0 m.
- the slag particles in the slurry are less likely to settle when the particle size is a certain size or less.
- particles of calcium silicate have a particle size of 1 ⁇ m or less, it takes 24 hours or more to settle 1 m in the slurry. Therefore, in the above method, the slag particles which become smaller than a certain size and the CO 2 aqueous solution easily penetrates to the inside of the particles and which easily dissolves calcium are difficult to settle, so they are close to the liquid surface of the crushing and settling tank Easy to stay on the upper side.
- slag particles on the surface of which silicon, aluminum, iron and manganese or their hydroxides, carbonates and hydrates etc. are precipitated are again precipitated due to the large particle size and are crushed and the surface is newly formed. Exposed.
- the above method is more efficient in eluting calcium from steelmaking slag by contact with a CO 2 aqueous solution, as compared with the case where the whole of the slag particles in the slurry is ground or the like using a ball mill or the like. Can be done.
- a wet crusher is used to smash while moving the entire combination of the slurry and balls like a ball mill etc., the entire slurry is stirred, so steelmaking slag is contacted with the balls in a low concentration state and crushed Ru. Therefore, a wet crusher such as a ball mill has poor efficiency such as crushing of steelmaking slag, and it is difficult to increase the elution amount of calcium. On the other hand, it is also considered that the elution amount of calcium can be increased by increasing the slag concentration and subjecting it to a wet pulverizer such as a ball mill.
- the efficiency of pulverization and the like does not decrease even if the relative amount of water in the slurry is increased. Therefore, it is possible to increase the amount of water that is a saucer of eluted calcium in the slurry, and it is possible to dissolve much calcium.
- the concentration of steelmaking slag in the slurry for increasing the elution amount of calcium can be 10 L / kg or more of the ratio of water to steelmaking slag (volume of water / mass of steelmaking slag) 30 L / kg or more is preferable, 50 L / kg or more is more preferable, and 100 L / kg or more is more preferable.
- the upper limit of the above ratio is not particularly limited, it can be 700 L / kg or less from the viewpoint of enhancing the efficiency such as crushing of settled slag.
- the said slurry should just be what suspended steelmaking slag in water. From the viewpoint of shortening the time to raise the carbon dioxide concentration of the CO 2 aqueous solution by introducing carbon dioxide and shortening the time to elute calcium, the supplied slurry suspended the steelmaking slag in the CO 2 aqueous solution It may be one.
- the type of steelmaking slag is not particularly limited as long as it is a slag discharged in the steelmaking process.
- steelmaking slag include converter slag, pretreated slag, secondary refining slag and electric furnace slag.
- steelmaking slag may use what was discharged
- the maximum particle size of the pre-crushed slag particles is preferably 1000 ⁇ m or less. When the maximum particle size is 1000 ⁇ m or less, the surface area per volume is large, and the aqueous solution of CO 2 can sufficiently penetrate into the inside of steelmaking slag, so that a large amount of calcium is eluted by contact with the aqueous solution of CO 2 Can. Steelmaking slag can be crushed or crushed to the above range by a known crusher.
- the maximum particle size of the slag particles is preferably 500 ⁇ m or less, more preferably 250 ⁇ m or less, and still more preferably 100 ⁇ m or less.
- the maximum particle size of the slag particles can be reduced to the above range by, for example, further crushing the crushed or crushed slag particles with a grinder including a hammer mill, a roller mill, a ball mill and the like.
- Steelmaking slag is a filtration residue slag obtained by filtering after making steelmaking slag into a container containing water, leaching of free lime and calcium hydroxide, and leaching of calcium on the surface of a Ca compound. May be By using the filtered residual slag, it is possible to use a slag in which calcium is eluted to some extent, so the load for eluting a larger amount of calcium can be reduced by the present embodiment.
- the filtered water from which calcium is leached (hereinafter, also simply referred to as “slag leachate”), which is obtained simultaneously at this time, is a highly alkaline aqueous solution having a pH of 11 or more.
- Slag leaching water can be used for precipitation of a calcium-containing solid component (precipitation step), as described later, when recovering calcium.
- slag leaching water can be used for applications requiring an alkaline aqueous solution, such as a neutralizing agent for acid wastewater.
- there is also a merit that kneading of water is not necessary when the hydration treatment is carried out by holding with water, which will be described later, using filtered residual slag.
- the amount of slag in the slurry is preferably 1 g / L or more and 100 g / L or less, more preferably 2 g / L or more and 40 g / L or less, from the viewpoint of sufficiently eluting calcium in steelmaking slag.
- the crushing of steelmaking slag in the crushing and settling tank has a maximum particle diameter of slag particles of 1000 ⁇ m or less, preferably 500 ⁇ m or less, more preferably 250 ⁇ m, It is more preferable to carry out until it becomes 100 micrometers or less more preferably.
- the crushed steelmaking slag elutes calcium by contact with a CO 2 aqueous solution.
- Carbon dioxide may be introduced in advance into the slurry before being introduced into the grinding / settling tank.
- calcium elutes calcium and carbon dioxide react with each other to form water-soluble calcium hydrogen carbonate, so that carbon dioxide in the slurry decreases as calcium dissolves. Therefore, from the viewpoint of enhancing the elution efficiency of calcium, it is preferable to introduce carbon dioxide into the slurry simultaneously with or after the pulverization and the like.
- Carbon dioxide can be introduced into the slurry, for example, by bubbling a gas containing carbon dioxide.
- a bubble refining device such as a known aeration tube or micro bubble device at the outlet of gas to reduce the bubbles (bubbles) of carbon dioxide.
- the quantity of free carbonic acid which may be contained in general tap water is 3 mg / L or more and 20 mg / L or less.
- the gas containing carbon dioxide may be pure carbon dioxide gas, or may be a gas containing components other than carbon dioxide (for example, oxygen or nitrogen).
- the gas containing carbon dioxide include exhaust gases after combustion, and a mixed gas of carbon dioxide, air and water vapor.
- the gas containing carbon dioxide has high carbon dioxide content. It is preferred to include at a concentration (eg, 90%).
- a gas containing carbon dioxide may be simply referred to as carbon dioxide.
- FIG. 1 is a schematic diagram which shows the structure of the apparatus used in order to elute calcium from steelmaking slag in this embodiment.
- the apparatus 100 for eluting calcium from the steelmaking slag shown in FIG. 1 is contained in the above-mentioned slurry in the grinding / settling tank 110 into which the slurry (shaded area in the drawing) is charged, and the bottom side inside the grinding / settling tank 110. It has the grinding mechanism 120 which grinds a steelmaking slag etc., and the carbon-dioxide introduction
- the grinding and settling tank 110 is a container into which the slurry is charged.
- the grinding / settling tank 110 can accommodate the grinding mechanism 120 and the carbon dioxide introduction unit 130 inside the container, and if the size of the slag particles contained in the input slurry can be sufficiently ground by the grinding mechanism 120 Good.
- the grinding / settling tank 110 may have a slurry inlet and a slurry outlet (both not shown).
- the pulverizing mechanism 120 is disposed on the bottom side of the pulverizing / settling tank 110, and pulverizes slag particles in the slurry that has settled on the bottom side of the pulverizing / settling tank 110.
- the grinding mechanism 120 constitutes a grinding area in the slurry.
- the crushing mechanism 120 is preferably disposed at a position where the height (depth) of the slurry from the liquid surface when the slurry is introduced into the crushing and settling tank 110 is 0.2 m or more, and 0.3 m or more It is more preferable to arrange in the following position, and it is more preferable to arrange in the position which will be 0.6 m or more.
- the upper limit of the height from the liquid surface of the slurry is not particularly limited, it can be 2.0 m.
- the distance from at least the upper surface inside the grinding / settling tank 110 to the upper end of the grinding mechanism 120 may be in the above range.
- the pulverizing mechanism 120 may have any configuration capable of pulverizing slag particles and the like so that stirring of the slurry is suppressed in the region on the upper side inside the pulverizing / settling tank 110 so that the steelmaking slag settles. It may be appropriately selected according to the size of the crushing and settling tank 110 and the like.
- the grinding mechanism 120 can be configured to cause the grinding medium 122 introduced to the bottom side of the grinding / settling tank 110 to flow by the stirring mechanism 124.
- the fluidized grinding medium 122 is in contact with the slag particles, and the fluidized and rotated grinding medium 122 slides the slag particles, and the slag particles are crushed more efficiently, etc. can do.
- the grinding medium 122 may be of any material and size capable of grinding slag particles and the like, and known balls used for a ball mill, known beads used for a bead mill, etc. can be used.
- the stirring mechanism 124 may be any mechanism as long as the grinding medium 122 can be made to flow and the slag particles can be crushed and the like.
- the stirring mechanism 124 can be a plurality of stirring impellers 124 a shown in FIG. 2A and a stirring screw 124 b shown in FIG. 2B.
- the stirring mechanism 124 can cause the grinding medium 122 to flow by the rotation of the stirring impeller 124a or the stirring screw 124b generated by rotating the rotating shaft 124c, and the slag particles can be crushed and the like.
- each stirring impeller 124a has a direction substantially orthogonal to the depth direction (hereinafter simply referred to It is preferable to arrange in an inclined manner with respect to the horizontal direction.
- FIG. 1 shows a direction substantially orthogonal to the depth direction
- stirring impeller 124a may be disposed only in one stage, or disposed as a plurality of stages so that grinding media 122 can flow at different depths in grinding / settling tank 110. It is also good.
- the rotary shaft 124c may extend from the liquid surface side of the grinding / settling tank 110 toward the bottom side as shown in FIG. 1, or as shown in FIG. 3 and FIG. It may extend from the bottom side of the settling tank 110 toward the liquid surface side.
- the pulverizing mechanism 120 has only one stirring mechanism 124, it has a plurality of stirring mechanisms 124 for flowing the grinding medium 122 at different places in the horizontal direction in the crushing / settling tank 110 or at different depths. You may
- the carbon dioxide introduction unit 130 has a flow path 132 of carbon dioxide communicating the external carbon dioxide supply source with the inside of the grinding / settling tank 110 and an inlet 134 opened in the grinding / settling tank 110, The carbon dioxide flowing through the passage 132 is introduced into the slurry introduced into the crushing and settling tank 110 from the inlet 134.
- the carbon dioxide introduction unit 130 simultaneously performs the introduction of carbon dioxide and the like by the crushing mechanism 120 and the like.
- the inlet 134 is preferably arranged to have the same depth as the grinding mechanism 120 or a depth near that. More preferably, they are arranged at the same depth as the grinding mechanism 120. Since the introduced gaseous carbon dioxide is dissolved in the aqueous solution of CO 2 while moving in the liquid surface direction (upper side direction) of the slurry regardless of the position where the introduction port 134 is disposed, the pulverization / settling tank An elution region in which the slurry contacts with carbon dioxide can be formed on the grinding mechanism 110 and the upper side closer to the liquid surface.
- the introduction port 134 is a diffusion tube which is a bubble refining device, and introduces the bubbles of the refined carbon dioxide into the inside of the crushing and settling tank 110.
- the carbon dioxide introduction unit 130 has a single flow passage 132 and an introduction port 134, but the carbon dioxide introduction unit 130 may use carbon dioxide from a single flow passage or a plurality of different flow passages. There may be a plurality of inlets 134 of different horizontal positions or depths in the grinding and settling tank 110 introduced into the slurry.
- the carbon dioxide introduction unit 130 may be configured to introduce carbon dioxide into the slurry from the stirring mechanism 124.
- the carbon dioxide introducing unit 130 can introduce carbon dioxide to the same depth as the crushing mechanism 120, so steel making in the state in which calcium is most easily eluted immediately after being crushed etc. Calcium can be easily eluted from the slag.
- FIG. 3 shows the configuration of an apparatus 200 used to elute calcium from steelmaking slag, having a carbon dioxide introduction unit 230 for introducing carbon dioxide into the slurry (shaded area in the drawing) from the stirring mechanism 224 of the grinding mechanism 220.
- the stirring mechanism 224 causes the grinding medium 222 of the grinding mechanism 220 to flow by the rotation of the stirring impeller 224 a generated by rotating the hollow rotary shaft 224 c inside the grinding / settling tank 210 to grind the slag particles, etc. Can.
- the hollow rotary shaft 224c simultaneously functions as the flow path 232 of the carbon dioxide introduction unit 230, and introduces carbon dioxide into the slurry from the carbon dioxide introduction port 234 provided at the tip.
- the rotary shaft 224c may be provided with a plurality of openings, and carbon dioxide may be introduced into the slurry from the shaft portion other than the tip.
- FIG. 4 shows another apparatus 300 used to elute calcium from steelmaking slag, having a carbon dioxide introduction unit 330 for introducing carbon dioxide into the slurry (the shaded area in the drawing) from the stirring mechanism 324 of the grinding mechanism 320.
- the stirring mechanism 324 includes a hollow rotary shaft 324c, a hollow rod-like stirring rod support 324d extending horizontally from the rotary shaft 324c in the grinding / settling tank 310, and a grinding / settling tank from the stirring rod support 324d. It has a bar-like stirring rod 324 e extending in the depth direction of 310.
- the hollow interior of the rotary shaft 324c and the hollow interior of the stirring rod support 324d are in fluid communication with each other, and the stirring rod support 324d is hollow interior and exterior And an inlet port 334 in fluid communication therewith.
- the stirring mechanism 324 causes the grinding medium 322 of the grinding mechanism 320 to flow by the rotation of the stirring rod 324e generated by rotating the hollow rotary shaft 324c inside the grinding / settling tank 310, and the slag particles are ground. Etc.
- the rotating shaft 324c and the stirring rod support 324d simultaneously function as the flow path 332 of the carbon dioxide introducing portion 330, and introduce carbon dioxide into the slurry from the introducing port 334 of the stirring rod support 324d.
- carbon dioxide can be introduced into a wider range of the slurry introduced into the crushing and settling tank 310, and calcium is eluted from the crushed steel slag for a longer period of time. It can be made easy.
- a plurality of openings may be provided in the tip of the rotary shaft 324c or in a shaft portion other than the tip, and carbon dioxide may be introduced into the slurry also from these openings.
- the number of stir bar supports 324d extending from one rotary shaft 324c, the number of stir bars 324e extending from one stir bar support 324d, and the introduction of one stir bar support 324d is not particularly limited, and may be one or more, but from the viewpoint of enhancing the efficiency such as crushing or the ease of elution of calcium from the steelmaking slag, all may be more than one. Is preferred.
- the stirring rod 324e may rotate itself. At this time, from the viewpoint of enhancing the efficiency such as grinding, when a plurality of stirring rods 324e extend from the stirring rod support 324d, one of the stirring rods 324d may rotate in a direction different from the other.
- the stirring rod 324e may be configured to be extensible and contractible in the depth direction of the crushing and settling tank 310. At this time, from the viewpoint of enhancing the efficiency such as crushing, when a plurality of stirring rods 324e extend from the stirring rod support 324d, one of the stirring rods 324e may expand and contract in a cycle different from the others.
- FIG. 5 is a schematic view showing a configuration of an apparatus 500 used for eluting calcium from steelmaking slag, in which a carbon dioxide introduction unit 530 is installed outside the crushing and settling tank.
- the carbon dioxide introduction unit 530 has a circulation type flow path 535 and a pump 536 for taking out the slurry inside the pulverization / settling tank 510 and re-inflowing into the pulverization / settling tank 510. It has an inlet 534 for introducing carbon.
- the outlet and re-inlet of the slurry from the grinding / settling tank 510 may have different heights, but preferably have the same height so as not to inhibit the sedimentation of the steelmaking slag.
- the crushing mechanism 120 can be made into the structure similar to FIG. 1, detailed description is abbreviate
- bubbles of carbon dioxide are refined by the shear force generated by the flow of steelmaking slag contained in the slurry, so the bubble refining device may not be disposed.
- FIGS. 1 to 5 the configuration of the device shown in FIGS. 1 to 5 is merely an example, and various modifications and arbitrary combinations of the configurations shown in the respective drawings are possible within the scope of the spirit of the present invention. It's too late.
- the carbon dioxide introduction portion has a hollow rotary shaft extending from the top side of the crushing / settling tank toward the bottom side, and the rotary shaft has its tip or hollow
- the carbon dioxide may be introduced into the slurry from an opening that allows the inside and the outside of the shaft portion to flow.
- the insides of the stirring impeller and the stirring screw as shown in FIG. 2A and FIG. 2B may be hollow so that carbon dioxide can be introduced into the slurry from the stirring impeller or the stirring screw.
- the carbon dioxide introduction part is an opening that makes the inside of the stirring rod hollow as shown in FIG. 4 and allows the inside or the outside of the rod portion of the hollow stirring rod to flow. It is also possible to introduce carbon dioxide into the slurry. On the other hand, carbon dioxide may not be introduced into the slurry from the stirring rod support and the stirring rod shown in FIG. 4, and carbon dioxide may be introduced into the slurry only from the rotating shaft.
- the carbon dioxide introducing unit is configured to introduce carbon dioxide from the separately provided flow path and inlet of carbon dioxide while introducing carbon dioxide from the stirring mechanism. It is also good.
- carbon dioxide is not introduced from the rotating shaft shown in FIG. 3 or the rotating shaft, stirring rod support or stirring rod shown in FIG. It may be configured to introduce carbon.
- carbon dioxide is introduced into the slurry inside the grinding / settling tank as in the apparatus shown in FIGS. 1, 3 and 4, and even outside the grinding / settling tank as in the apparatus shown in FIG. Carbon dioxide may be introduced into the slurry.
- the number of stirring mechanisms is not particularly limited, and may be one or more.
- the respective rotation shafts of the plurality of stirring mechanisms may rotate in the same direction, but in order to further increase the efficiency such as crushing, any rotation shaft The body may rotate in a different direction than the others.
- the amount of Ca compound eluted from steelmaking slag when compared under the same conditions (water / slag ratio etc.) other than the Ca elution method Is expected to increase the recovery of calcium from steelmaking slag.
- the steelmaking slag is subjected to hydration treatment before calcium is eluted according to the first embodiment described above.
- FIG. 6 is a flowchart showing an exemplary step of the method of eluting calcium from steelmaking slag according to the present embodiment.
- the steelmaking slag is subjected to a hydration treatment (step S110), and thereafter, calcium is eluted from the steelmaking slag according to the first embodiment described above (step S130).
- calcium in steelmaking slag is free lime, calcium hydroxide (Ca (OH) 2 ), calcium carbonate (CaCO 3 ), calcium silicate (Ca 2 SiO 4 , Ca 3 SiO 5 ) and calcium oxide It exists as a compound such as iron aluminum (Ca 2 (Al 1 -x Fe x ) 2 O 5 ).
- Ca hydrate formed by the above reaction and the like is easily dissolved in a CO 2 aqueous solution. Therefore, the hydration treatment makes it easier to elute calcium derived from calcium silicate and calcium iron oxide aluminum etc. contained in steelmaking slag.
- free lime is easily dissolved in a CO 2 aqueous solution, it is generally contained in the steelmaking slag only at less than about 10% by mass.
- calcium silicate is generally contained in about 25% by mass to 70% by mass in steelmaking slag, and calcium iron aluminum is usually contained in about 2% by mass to about 30% by mass in steelmaking slag. Therefore, if calcium contained in calcium silicate and calcium iron oxide is easily eluted by CO 2 aqueous solution by hydration treatment, the elution amount of calcium from steelmaking slag to CO 2 aqueous solution can be increased. It will also be possible to recover calcium from slag in a shorter time.
- the sum of the volumes of compounds produced by the hydration treatment will usually be greater than the sum of the volumes of the compounds prior to reaction. Furthermore, during the hydration process, part of the free lime in the steelmaking slag elutes into the water for treatment. Therefore, when the hydration treatment is performed, a crack is generated inside the slag particle, and the slag particle is easily broken starting from the crack. Thus, when the slag particles are disintegrated, the particle diameter of the slag particles is reduced, the surface area per volume is increased, and the water or the CO 2 aqueous solution can sufficiently penetrate to the inside of the steelmaking slag. Many Ca compounds can be hydrated in step S110), and more calcium can be eluted in the calcium elution step (step S130).
- the hydration treatment may be performed by a method and conditions under which the Ca compound, preferably calcium silicate or calcium iron aluminum oxide, contained in the steelmaking slag can be hydrated.
- the Ca compound preferably calcium silicate or calcium iron aluminum oxide
- a treatment for settling steelmaking slag immersed in water and settled (hereinafter, also simply referred to as “immersion and standing”), stirring or crushing steelmaking slag immersed in water, etc.
- Treatment (hereinafter, also simply referred to as “immersion and agitation, etc.”), treatment of leaving a paste containing water and slag particles (hereinafter, also simply referred to as “pasted and settled”), and a sufficient amount of water vapor
- the processing hereinafter, also simply referred to as "wet and stand” or the like in which the steelmaking slag is allowed to stand is included in the container having the same. According to these methods, steelmaking slag and water can be brought into sufficient contact.
- the hydration treatment only one of the above-mentioned immersion and standing, immersion and stirring, pastelization and wet and standing, etc. may be applied, or two or more of these may be carried out in any order. .
- the hydration treatment by immersion stirring or the like is preferable from the viewpoint of making the calcium more easily eluted by performing the hydration treatment sufficiently to the inside of the slag particles.
- Immersion stirring etc. may stir steelmaking slag soaked in water inside a container having a stirring impeller, or stir steelmaking slag in a crushing and settling tank or a ball mill usable in the first embodiment described above. It may be crushed while doing so. From the viewpoint of facilitating the elution of calcium more easily by the hydration treatment to the inside of the slag particles, it is preferable to immerse and stir the steelmaking slag while stirring the steelmaking slag.
- the reaction by the above-mentioned hydration treatment occurs due to the contact of the Ca compound and water near or inside the surface of the steelmaking slag.
- the amount of contact with water is larger in the vicinity of the surface. Therefore, Ca hydrate is more likely to be generated near the surface of steelmaking slag.
- the components contained in steelmaking slag are dissolved in water used for hydration treatment, Fe, Al, Si and Mn or their hydroxides, carbonates, and oxides are dissolved as in the above-mentioned dissolution in CO 2 aqueous solution. Hydrates may remain or precipitate on the surface of steelmaking slag. When these remaining or precipitated substances inhibit the penetration of water into the inside of the steelmaking slag, Ca hydrate is less likely to be formed inside the steelmaking slag.
- the surface area of the slag particles is increased by crushing the steelmaking slag immersed in water during the hydration treatment, and the contact area between water and the slag particles is further increased.
- a new surface where the above-mentioned substance has not yet remained or precipitated is continuously formed, and water is continuously formed from the continuously formed surface to the inside of steelmaking slag.
- the Ca hydrate is more likely to be formed inside the steelmaking slag.
- the above-mentioned remaining or precipitated substances are removed, the contact area between water and slag particles becomes larger, and water is more likely to penetrate inside steelmaking slag. Become.
- the hydration treatment may be performed by a processing apparatus different from the grinding / settling tank used in the first embodiment, but from the viewpoint of simplifying the process, the grinding / settling tank used in the first embodiment Hydration treatment by immersion and standing or immersion stirring in an internal or other wet grinding apparatus, for example, hydration treatment by immersion stirring in a grinding / settling tank or other wet grinding apparatus used in the first embodiment You may At this time, if processing similar to that of the first embodiment or processing similar to pulverization by a common other wet pulverizing apparatus is performed except that carbon dioxide is introduced, hydration processing such as immersion stirring can be performed.
- the above-mentioned hydration treatment by immersion stirring and the like and the elution of calcium according to the first embodiment are discharged from the grinding / settling tank and reloaded into the grinding / settling tank. Since it becomes unnecessary to move the slurry etc. without putting in between, hydration and elution of calcium can be performed more easily.
- the water used for the hydration treatment is non-ionized free carbon dioxide and ionized bicarbonate ions (HCO 3 ⁇ ) etc.
- the content of carbon is preferably less than 300 mg / L. If the content of carbon dioxide is less than 300 mg / L, it is difficult to elute calcium compounds other than free lime and calcium hydroxide in water used for hydration treatment, so most of the calcium contained in steelmaking slag is calcium It can be eluted in a CO 2 aqueous solution in the elution step, and the calcium recovery step is less likely to be complicated.
- the temperature of water used for the hydration treatment may be a temperature at which the water does not evaporate violently.
- the temperature of water is preferably 100 ° C. or less.
- the temperature of the water may be 100 ° C. or higher as long as it is equal to or lower than the boiling point of water at the pressure when the hydration treatment is performed. .
- the temperature of the water when the hydration treatment is performed by immersion and standing or immersion stirring is 0 ° C.
- the upper limit of the temperature is not particularly limited, but in view of the pressure resistance of the apparatus and the economical aspect, 300 ° C. or less is preferable. Moreover, it is preferable that the temperature at the time of giving a hydration process by paste formation stationary is 0 degreeC or more and 70 degrees C or less.
- the duration of the hydration treatment can be optionally set depending on the average particle diameter of the slag and the temperature (the temperature of the air containing water or water vapor) for the hydration treatment.
- the duration of the hydration treatment may be shorter as the average particle diameter of the slag is smaller, and may be shorter as the temperature at which the hydration treatment is performed is higher.
- the duration of the hydration treatment should be about 8 hours continuously. And preferably 3 hours to 30 hours.
- the duration of the hydration treatment is preferably continuously 0.6 hours or more and 8 hours or less.
- the duration of the hydration treatment is continuously 0.1 hour or more It is preferable to set it as 5 hours or less, and it is more preferable to set it as 0.2 hours or more and 3 hours or less.
- the duration of the hydration treatment is such that the maximum particle diameter of the slag particles is 1000 ⁇ m or less, preferably 500 ⁇ m or less, more preferably 250 ⁇ m, more preferably It is preferable to carry out until 100 ⁇ m or less.
- the hydration treatment is preferably carried out to such an extent that calcium silicate is sufficiently hydrated and calcium hydroxide, or calcium iron oxide is sufficiently hydrated to be calcium oxide-based.
- the hydration treatment is preferably performed until the amount of calcium silicate contained in the steelmaking slag is 50% by mass or less, or the amount of calcium iron aluminum oxide is 20% by mass or less.
- the Ca compound contained in the steelmaking slag in particular calcium silicate and calcium iron oxide, is hydrated to be Ca hydrate which is more easily eluted in the CO 2 aqueous solution. Because it is possible, more calcium can be eluted into the aqueous solution of CO 2 in a shorter time. In addition, the hydration process in the second embodiment can be easily performed, so the burden of costs at the time of implementation is small.
- the steelmaking slag is subjected to magnetic separation before the calcium is eluted according to the first embodiment described above.
- FIG. 7 is a flow chart showing an exemplary process of the method for eluting calcium from steelmaking slag according to the present embodiment.
- the steelmaking slag is subjected to magnetic separation (step S120), and thereafter, calcium is eluted from the steelmaking slag according to the first embodiment described above (step S130).
- Magnetic separation can be performed using a known magnetic separator.
- the magnetic separator may be either dry or wet, and can be selected according to the state of the steelmaking slag (whether dry or slurry).
- the magnetic separator can be appropriately selected from a drum type, a belt type, a flow type between fixed magnets, etc. In particular, it is easy to sort steelmaking slag contained in the slurry, and the magnetic force is increased to increase the magnetic separation amount.
- a drum type is preferable because it is easy.
- the magnet used by the magnetic separator may be a permanent magnet or an electromagnet.
- the magnetic flux density by the magnet may be such that it can selectively capture iron-based compounds and metallic iron from other compounds contained in steelmaking slag, and can be, for example, 0.003 T or more and 0.5 T or less, 0 It is preferable to set it to .005T or more and 0.3T or less, and it is more preferable to set it to 0.01T or more and 0.15T or less.
- magnetic separation does not have to be applied until all of the iron-based compounds contained in the steelmaking slag are removed. Even if the amount of the iron-based compound removed from the steelmaking slag by magnetic separation is small, the effect of the present invention is exhibited that calcium is more easily eluted in the aqueous CO 2 solution than in the prior art. Therefore, the time and the number of times of magnetic separation may be selected appropriately according to the influence of the magnetic selection on the manufacturing cost.
- the steelmaking slag is heat-treated, the magnetization of the iron-based compound and the metallic iron is increased, and a larger amount of iron-based compound can be removed by magnetic separation.
- the heat treatment is preferably performed at 300 ° C. or more and 1000 ° C. or less for 0.01 minutes or more and 60 minutes or less.
- the steelmaking slag may be in a dry state at the time of magnetic separation, but is preferably in the form of a slurry dispersed in water.
- a slurry dispersed in water since the slag particles are easily dispersed due to the polarity of water molecules, water flow and the like, it is easy to selectively capture the iron-based compound and the metallic iron by the magnetic force.
- the slag particles when the particle size of the slag particles is 1000 ⁇ m or less, in a gas such as air, the slag particles are caused by the liquid cross-linking ability by condensation of water vapor in the atmosphere, the van der Waals force between the slag particles, the electrostatic force between the slag particles Although they tend to aggregate, the slurry particles can sufficiently disperse the slag particles.
- metallic iron in steelmaking slag is minute, it is difficult to capture it when the steelmaking slag is dry, but when the steelmaking slag is made slurry, metallic iron dispersed in water also becomes easy to be trapped by magnetic separation.
- the slurry after removing the iron-based compound and metallic iron by magnetic separation may be used as it is for elution of calcium according to the first embodiment, but when the steelmaking slag is in a slurry form, solid-liquid separation is performed to make the steelmaking slag. It is preferable to separate the liquid and the liquid component. Solid-liquid separation can be performed by known methods including vacuum filtration and pressure filtration.
- the liquid component obtained by the above solid-liquid separation (hereinafter, also simply referred to as "magnetic water separation”) is alkaline because it contains calcium eluted from steelmaking slag in addition to water used for slurrying. Therefore, it is possible to use the liquid component to increase the pH of when precipitating calcium from CO 2 aqueous solution after elution of calcium in contact with later-described, steelmaking slag, CO 2 solution.
- the magnetic separation removal slag removed from the steelmaking slag by magnetic separation contains a large amount of iron-based compounds and compounds containing Fe such as metallic iron as described above, it can be reused as a raw material for blast furnace and sintering.
- either one or both may be performed.
- either of the hydration treatment and the magnetic separation may be performed first, or both of the wet magnetic separation and the wet magnetic separation may be simultaneously performed.
- hydration treatment in particular, hydration treatment by immersion stirring
- magnetic separation is performed, whereby the recovery rate of calcium is further increased, particularly when the device is enlarged.
- the whole processing can be performed in a shorter time.
- the compound containing iron remaining or precipitated on the surface of steelmaking slag inhibits the contact between the above-mentioned CO 2 aqueous solution and the surface of steelmaking slag, and the compound containing iron having a relatively high hardness It is considered that the inhibition of the grinding or grinding due to the above can be suppressed, and the Ca in the steelmaking slag can be easily eluted by the aqueous solution of CO 2 .
- calcium iron aluminum contained in steelmaking slag is difficult to be magnetized after Ca is eluted by contact with a CO 2 aqueous solution, and recovery by magnetic separation is not easy.
- calcium iron aluminum oxide in steelmaking slag can also be recovered by performing magnetic separation prior to contact with a CO 2 aqueous solution, and iron derived from calcium iron aluminum can also be reused more easily.
- FIG. 8 is a flow chart of a method of recovering calcium from steelmaking slag according to the present invention. As shown in FIG. 8, the method includes the steps of eluting calcium (step S100) and recovering calcium (step S200).
- Step S100 In the step of eluting calcium (step S100), calcium is eluted from steelmaking slag.
- the elution of calcium may be carried out by the methods described as the first to third embodiments described above.
- step S200 recovery of calcium (step S200) may be performed in a grinding / settling tank in which elution of calcium has been performed unless it becomes difficult.
- FIG. 9 is a flow chart showing an example of the step of recovering calcium (step S200).
- the step of recovering calcium (step S200) is, for example, a step of separating steelmaking slag and a CO 2 aqueous solution (step S210: hereinafter, also referred to as "separation step"), calcium is precipitated.
- step S220 hereinafter, also referred to as "precipitation step”
- step S230 a step of recovering the precipitated solid component
- a CO 2 aqueous solution in which calcium is dissolved is separated from steelmaking slag (step S210).
- the separation can be carried out by known methods. Examples of separation methods include filtration and methods in which a CO 2 aqueous solution is allowed to settle to precipitate steelmaking slag.
- separation methods include filtration and methods in which a CO 2 aqueous solution is allowed to settle to precipitate steelmaking slag.
- the supernatant liquid may be further recovered, or in the two-component system including the supernatant liquid and the precipitated steelmaking slag unless the solid component deposited in the later step is mixed with the steelmaking slag.
- the subsequent steps may be performed only on the supernatant fluid.
- step S220 calcium eluted in a CO 2 aqueous solution is precipitated as a solid component containing calcium.
- Calcium eluted in a CO 2 aqueous solution can be precipitated by a known method.
- Examples of the method of precipitating calcium eluted in a CO 2 aqueous solution as a solid component include a method of removing carbon dioxide from a CO 2 aqueous solution and a method of raising the pH of the CO 2 aqueous solution.
- ⁇ Removal of carbon dioxide> carbon dioxide can be removed from the CO 2 aqueous solution separated from the steelmaking slag in the separation step (step S210), and calcium eluted in the CO 2 aqueous solution can be precipitated in the step of eluting calcium (step S100).
- the Ca compound precipitated at this time include calcium carbonate, calcium carbonate hydrate and calcium hydroxide.
- the method for removing carbon dioxide from the CO 2 aqueous solution is not particularly limited.
- methods of removing carbon dioxide include (1) gas introduction, (2) vacuum and (3) heating.
- the gas to be introduced may be a gas that reacts with water (chlorine gas, sulfur dioxide gas, etc.), but the calcium formed by the ions formed by introducing it into the CO 2 aqueous solution and the calcium dissolved in water forms a salt. From the viewpoint of suppressing a decrease in the amount of precipitation, it is preferable that the gas has low reactivity with water.
- the gas introduced into the CO 2 aqueous solution may be an inorganic gas or an organic gas.
- inorganic gases are more preferable because they have less possibility of combustion or explosion even if they leak to the outside.
- inorganic gases having low reactivity with water include air, nitrogen, oxygen, hydrogen, argon and helium and mixed gases thereof.
- the mixed gas includes the air of the environment in which the present process is performed, which contains nitrogen and oxygen in a ratio of approximately 4: 1.
- Examples of organic gases having low reactivity with water include methane, ethane, ethylene, acetylene, propane and fluorocarbons.
- the above (1) to (3) may be combined.
- what is necessary is just to select the optimal combination in consideration of the supply system of gas or heat, a location, utilization of by-product gas in a factory, etc. of these combinations.
- the effect and removal effect of carbon dioxide removal by the introduction of the gas, and the reduced pressure of the aqueous solution of CO 2 The effect of removing carbon dioxide can be obtained, and carbon dioxide can be removed efficiently. At this time, further heating further promotes the effect of removing carbon dioxide. At this time, the additive effect of the decompression effect as CO 2 aqueous solution introduced into the CO 2 aqueous solution of the gas, for the carbon dioxide can be easily removed, it is not necessary to raise the heating temperature, The heating cost can be reduced.
- step S210 When calcium starts to precipitate, turbidity due to calcium carbonate is generated in the aqueous solution of CO 2 . It is sufficient if the pH of the aqueous solution of CO 2 is raised to such an extent that this cloudiness can be confirmed visually. From the viewpoint of more fully depositing calcium and increasing the recovery rate of calcium, raising the pH by 0.2 or more with respect to the pH of the CO 2 aqueous solution separated from the steelmaking slag in the separation step (step S210) Preferably, it is more preferably 0.3 or more, more preferably 1.0 or more, still more preferably 1.5 or more, and even more preferably 2.0 or more.
- the pH of the CO 2 aqueous solution can be measured by a known glass electrode method.
- step S230 solid components containing not only calcium but also other elements such as phosphorus are precipitated in this step, according to the present inventor's knowledge, solid components which precipitate immediately after starting to raise the pH (hereinafter referred to simply as “initial precipitation
- the content of the phosphorus-containing compound (hereinafter, also simply referred to as “phosphorus compound”) is higher, and the later precipitated solid component (hereinafter, also simply referred to as “late precipitate”) has a higher content ratio. Lower phosphorus content ratio. Therefore, the step of recovering (step S230) to be described later is performed while raising the pH, and the initial precipitate is recovered to separate the solid component having a higher ratio of phosphorus and the solid component having a lower ratio of phosphorus. Can be collected.
- Phosphorus compounds recovered from steelmaking slag can be reused as phosphorus resources. Therefore, when the solid component having a high content of phosphorus compound is recovered, reuse of phosphorus is facilitated. Moreover, although Ca compound collect
- the initial precipitate may be recovered before the pH rises by 1.0.
- PH of CO 2 aqueous solution for example, by introducing an alkaline substance into CO 2 aqueous solution, can be increased.
- alkaline substances that can be introduced into the aqueous CO 2 solution include calcium hydroxide, ammonia and sodium hydroxide.
- calcium hydroxide, ammonia or sodium hydroxide When calcium hydroxide, ammonia or sodium hydroxide is introduced, a solution of these substances in water may be added to the aqueous CO 2 solution.
- Calcium hydroxide, ammonia and sodium hydroxide may be commercially available, or may be contained in waste liquid or other liquid. When calcium hydroxide in waste liquid is charged, for example, the waste liquid produced in the reaction of calcium carbide (calcium carbide) with water to produce acetylene can be added to the aqueous CO 2 solution.
- slag leaching water prepared by immersing steelmaking slag in water, the above-mentioned magnetic separated water or the above-mentioned hydration treated water may be introduced into the above-mentioned CO 2 aqueous solution.
- Slag leachate, magnetic separation water and hydration treated water may be obtained by immersion in water, magnetic separation or hydration treatment of steelmaking slag from which calcium is to be recovered, or water of another steelmaking slag. It may be obtained by immersion, magnetic separation or hydration treatment.
- alkaline substances it is preferable to use calcium hydroxide, calcium hydroxide-based waste solution, slag leachate, magnetic separation water, hydration treated water.
- the CO 2 aqueous solution after calcium recovery by the method according to the present embodiment can simplify or eliminate the waste water treatment, thereby suppressing the cost of the waste water treatment.
- the aqueous solution of CO 2 after recovery of calcium contains almost no metal element such as Ca, Fe, Mn, Al, P and CO 2 , it can be reused in the process, enabling waste water elimination obtain.
- the removal of carbon dioxide and the increase in pH may be performed in combination.
- the solid component precipitated in the precipitation step (step S220) is recovered (step S230).
- the precipitated solid component can be recovered by known methods including vacuum filtration and pressure filtration.
- This solid component includes calcium derived from steelmaking slag.
- Example 1 The steelmaking slag which has a component ratio of Table 1 was prepared. In addition, the component of steelmaking slag was measured by the chemical analysis method. The steelmaking slag was pre-crushed and then passed through a sieve with an opening of 106 ⁇ m.
- a part of the steelmaking slag shown in Table 1 was subjected to hydration treatment by the following method (hydration treatment-1). Thereafter, either the non-hydrated steelmaking slag or the above-mentioned hydrated steelmaking slag was brought into contact with the aqueous CO 2 solution by the following method (any of Ca elution-1 to Ca elution-3). Then, the elution rate of calcium to the CO 2 aqueous solution was measured.
- any of the non-hydrated steelmaking slag and the above-mentioned hydrated steelmaking slag in the amounts shown in Table 2 is added, water is added so that the total amount of water is 30 L, and then the ball mill is The steelmaking slag was crushed by rotating the ball at 70 rpm and bringing the rotating ball into contact with the steelmaking slag. At the same time, carbon dioxide in an amount of 9 L / min was introduced into the slurry in which steelmaking slag was suspended in water.
- the slurry is filtered to separate the aqueous solution of CO 2 in the slurry, and the calcium concentration in the aqueous solution of CO 2 is measured by the chemical analysis method did.
- the amount of calcium eluted in the aqueous solution of CO 2 is calculated from the measured concentration of calcium in the aqueous solution of CO 2 and the amount of water introduced, divided by the amount of calcium in the steelmaking slag introduced, calcium to the aqueous solution of CO 2 The elution rate of was calculated.
- Table 2 shows the presence or absence of hydration and the method of hydration when hydration is carried out, the Ca elution method (any of the above Ca elution-1 to Ca elution-4), slag put into the grinding / settling tank or ball mill The amount and the calcium elution rate (Ca elution rate) measured by the above calculation are shown.
- a grinding area on the bottom side for grinding steelmaking slag, etc. and an elution area on the upper side closer to the liquid surface than the grinding area are provided inside the grinding / settling tank, and the steelmaking slag is ground in the elution area while grinding steelmaking slag.
- the Ca elution rate was higher than in 7-11 and 14-15.
- the Ca elution rate was higher as the water / slag ratio corresponding to the amount of water to steelmaking slag was higher.
- test No. 1 in which the steelmaking slag was subjected to hydration treatment before being brought into contact with the CO 2 aqueous solution. 12 to 13 had a higher Ca elution rate.
- Example 2 The steelmaking slag shown in Table 1 was crushed so that the diameter was 5 mm or less. Thereafter, the crushed steelmaking slag was heated at 750 ° C. for 40 minutes in the atmosphere. The heated steelmaking slag was further crushed after cooling, and then passed through a sieve with an opening of 106 ⁇ m.
- a part of the steelmaking slag was magnetically separated by the following method (magnetic separation -1). Thereafter, the steelmaking slag not subjected to the magnetic separation or the steelmaking slag subjected to the magnetic separation was subjected to hydration treatment by the following method (any of hydration treatment-2 to hydration treatment-4). Thereafter, the non-hydrated steelmaking slag and the above-mentioned hydrated steelmaking slag were brought into contact with a CO 2 aqueous solution in the same manner as in Experiment 1 (either Ca elution-1 or Ca elution-3).
- the steelmaking slag is further crushed using the same grinding / settling tank or ball mill containing the slurry after hydration treatment. Carbon dioxide was introduced into the slurry while equalizing. Then, the elution rate of calcium to the CO 2 aqueous solution was measured.
- Magnetic selection 0.15 kg of the above steelmaking slag is suspended in 7.5 L of water to form a slurry, which is put into a drum type magnetic separator and charged with a maximum magnetic flux density of 0.03 T on the drum surface and a drum peripheral velocity of 3 m / min. I chose magnetic.
- the concentration of iron in the steelmaking slag after magnetic separation was measured by chemical analysis, and it was found that 30% by mass of the iron element contained in the first steelmaking slag was removed.
- the amount of calcium eluted in the aqueous solution of CO 2 is divided by the amount of calcium in the steelmaking slag measured after the magnetic separation to eliminate the influence of the removal of calcium by the magnetic separation to obtain the aqueous solution of CO 2
- the elution rate of calcium was calculated.
- Table 3 shows the presence or absence of magnetic separation, the presence or absence of hydration, and the method of hydration when hydration is performed (any of the above hydration treatment-2 to hydration treatment-4), the Ca elution method (the above Ca elution 1 and Ca elution -3), and the calcium elution rate (Ca elution rate) measured by the above calculation are shown.
- Test was carried out hydration treatment prior to contact with the CO 2 solution No. 21, test No. 22 and the test No. No. 24 had a higher Ca elution rate than the case without hydration treatment (in particular, comparison between Test No. 22 and Test No. 23). Furthermore, tests were conducted magnetic separation prior to contact with the CO 2 solution No. Test No. 22 to No. 22 No. 24 had a higher Ca elution rate than the case where magnetic separation was not performed (in particular, comparison between Test No. 22 and Test No. 21).
- Example 3 The steelmaking slag shown in Table 1 was crushed so that the diameter was 5 mm or less. Thereafter, the crushed steelmaking slag was heated at 750 ° C. for 40 minutes in the atmosphere. The heated steelmaking slag was further crushed after cooling, and then passed through a sieve with an opening of 106 ⁇ m.
- a portion of the steelmaking slag was hydrated by the following method (hydration-5). Thereafter, the hydrated steelmaking slag was magnetically selected by the following method (one of magnetic selection-2 to magnetic selection-3). Thereafter, the slurry remaining after magnetic separation was brought into contact with a CO 2 aqueous solution in the same manner as in Experiment 1 (Ca elution-1).
- Table 4 shows the calcium elution rate (Ca elution rate) when the above hydration and magnetic separation were performed.
- the method of calculating the dissolution rate was the same as in Experiments 1 and 2.
- test No. 1 which performed magnetic selection after performing a hydration process. All of 31 to 32 had high Ca elution rates.
- the method for eluting calcium according to the present invention is useful as a method for recovering calcium resources in steelmaking because it can easily increase the elution amount of calcium in steelmaking slag to an aqueous solution containing carbon dioxide.
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Abstract
The purpose of the present invention is to provide a method for eluting calcium from a steel-making slag, with which a larger amount of calcium can be easily eluted from the steel-making slag to an aqueous solution comprising carbon dioxide. To this end, the present invention relates to a method for eluting calcium from a steel-making slag. In the present invention, stirring of a slurry comprising a steel-making slag is suppressed in a region within a pulverizing/settling tank on the top side near a liquid surface to cause the steel-making slag to settle, while at the same time the steel-making slag included in the slurry is pulverized or the surface of the steel-making slag is crushed in a region within the pulverizing/settling tank on the bottom side. Carbon dioxide is introduced into the slurry, and the pulverized or crushed steel-making slag is contacted with an aqueous solution in which the carbon dioxide is dissolved.
Description
本発明は、製鋼スラグからカルシウムを溶出させる方法、製鋼スラグからカルシウムを回収する方法、および製鋼スラグからカルシウムを溶出させる装置に関する。
The present invention relates to a method of eluting calcium from steelmaking slag, a method of recovering calcium from steelmaking slag, and an apparatus for eluting calcium from steelmaking slag.
製鋼工程で生じる製鋼スラグ（転炉スラグ、予備処理スラグ、二次精錬スラグおよび電気炉スラグなど）は、セメント材料、道路用路盤材、土木用材料および肥料を含む広い用途に用いられる（非特許文献１～３参照）。また、上記用途に用いられない一部の製鋼スラグは、埋め立て処分されている。
Steelmaking slag (such as converter slag, pretreated slag, secondary refining slag and electric furnace slag) generated in the steelmaking process is used in a wide range of applications including cement materials, road base materials for roads, civil engineering materials and fertilizers (non-patented) See documents 1 to 3). In addition, some steelmaking slags not used for the above applications are disposed of in landfills.
製鋼スラグには、カルシウム（Ｃａ）、鉄（Ｆｅ）、ケイ素（Ｓｉ）、マンガン（Ｍｎ）、マグネシウム（Ｍｇ）、アルミニウム（Ａｌ）、リン（Ｐ）、チタン（Ｔｉ）、クロム（Ｃｒ）、硫黄（Ｓ）などの元素が含まれていることが知られている。これらのうち、製鋼スラグに最も多く含まれる元素は、製鋼工程で多量に用いられるカルシウムであり、通常、Ｆｅが次に多く含まれる。通常、製鋼スラグの全質量のうち、２０質量％～５０質量％程度がカルシウムであり、１質量％～３０質量％程度がＦｅである。
As steelmaking slag, calcium (Ca), iron (Fe), silicon (Si), manganese (Mn), magnesium (Mg), aluminum (Al), phosphorus (P), titanium (Ti), chromium (Cr), It is known that elements such as sulfur (S) are contained. Among these, the element contained most in steelmaking slag is calcium used in large amounts in the steelmaking process, and usually Fe is next contained in a large amount. Usually, of the total mass of steelmaking slag, about 20% by mass to about 50% by mass is calcium, and about 1% by mass to about 30% by mass is Fe.
製鋼スラグ中のカルシウムは、製鋼工程で投入される生石灰（ＣａＯ）がそのまま残存もしくは製鋼スラグの凝固中に析出した遊離石灰（ＣａＯ）、遊離石灰（ＣａＯ）が空気中の水蒸気もしくは二酸化炭素と反応して生成する水酸化カルシウム（Ｃａ（ＯＨ）２）もしくは炭酸カルシウム（ＣａＣＯ３）、またはカルシウムがＳｉやＡｌなどと反応して生成するケイ酸カルシウム（Ｃａ２ＳｉＯ４もしくはＣａ３ＳｉＯ５など）もしくは酸化カルシウム鉄アルミニウム（Ｃａ２（Ａｌ１－ＸＦｅＸ）２Ｏ５）などの形態で存在している（以下、製鋼スラグ中に存在する上記カルシウムを含む化合物を総称して、「Ｃａ化合物」ともいう。）。
The calcium in steelmaking slag is the reaction of free lime (CaO) and free lime (CaO) deposited in the solidification of steelmaking slag, as the raw lime (CaO) supplied in the steelmaking process remains or as it reacts with water vapor or carbon dioxide in the air. Calcium hydroxide (Ca (OH) 2 ) or calcium carbonate (CaCO 3 ), or calcium silicate (such as Ca 2 SiO 4 or Ca 3 SiO 5 ) formed by the reaction of calcium with Si or Al, etc. Or calcium iron oxide (Ca 2 (Al 1 -x Fe x ) 2 O 5 ) or the like (hereinafter referred to collectively as "Ca compound, generically containing compounds containing the above-mentioned calcium present in steelmaking slag It is also called ").
炭酸カルシウムおよび酸化カルシウムは、製鉄工程中の製銑工程および製鋼工程での主要なスラグ形成材であり、そのスラグの塩基度および粘性の調整剤、ならびに溶鋼からの脱リン剤などとして使用されている。また、酸化カルシウムに加水して得られる水酸化カルシウムは、排水工程で酸などの中和剤として使用されている。したがって、上記製鋼スラグ内に含まれるＣａ化合物を回収して製鉄工程に再利用すれば、製鉄のコストを削減できると期待されている。
Calcium carbonate and calcium oxide are main slag forming materials in iron making process and steel making process in iron making process, and are used as a modifier of basicity and viscosity of the slag and as a dephosphorization agent from molten steel There is. In addition, calcium hydroxide obtained by watering calcium oxide is used as a neutralizing agent such as acid in a drainage process. Therefore, it is expected that the cost of steelmaking can be reduced if the Ca compound contained in the steelmaking slag is recovered and reused in the steelmaking process.
また、今後、製鋼スラグを道路用路盤材、土木用材料またはセメント材料などとして使用するための土木工事の数が減少したり、製鋼スラグを埋め立て処分できる土地が減少したりすることが予想される。この観点からも、製鋼スラグに含まれるＣａ化合物を回収して、再利用または埋め立て処分される製鋼スラグの体積を減少させることが期待されている。
In addition, it is expected that the number of civil engineering works for using steelmaking slag as road base material for roadways, material for civil engineering or cement material decreases in the future or land that can make landfill disposal of steelmaking slag decrease . From this point of view as well, it is expected that the Ca compound contained in the steelmaking slag is recovered to reduce the volume of the steelmaking slag to be recycled or disposed of in landfills.
製鋼スラグ内のカルシウムは、たとえば、塩酸、硝酸または硫酸などの酸性水溶液に溶出させて、回収することができる。しかし、この方法において生成する、カルシウムと上記酸との塩は、再利用が困難である。たとえば、製鋼スラグ内のカルシウムを塩酸に溶出させて生成する塩化カルシウムは、加熱して酸化物にすれば再利用可能だが、上記加熱中に生じる有害な塩素ガスの処理コストが高いという問題がある。また、製鋼スラグ内のカルシウムを酸性水溶液に溶出させて回収しようとすると、酸の購入および溶出処理後の酸の廃棄のコストが高いという問題もある。
Calcium in steelmaking slag can be recovered, for example, by eluting it in an acidic aqueous solution such as hydrochloric acid, nitric acid or sulfuric acid. However, the salts of calcium and the acid formed in this method are difficult to reuse. For example, calcium chloride produced by eluting calcium in steelmaking slag into hydrochloric acid can be reused if it is heated to form oxides, but there is a problem that the processing cost of harmful chlorine gas generated during the above heating is high . In addition, when calcium in the steelmaking slag is eluted and recovered in an acidic aqueous solution, there is also a problem that the cost of purchasing the acid and discarding the acid after the elution process is high.
これに対し、二酸化炭素を含有する水溶液（以下、単に「ＣＯ２水溶液」ともいう。）に製鋼スラグからカルシウムを溶出させて回収すれば、酸の使用による上記問題を解決できると期待されている（特許文献１～３参照）。なお、二酸化炭素は、排ガス中に多く含まれ、排ガスを脱硫および脱硝した後は、空気と水蒸気以外は、ほとんど二酸化炭素となった気体が得られる。工業的には非特許文献４に示すように排ガスから二酸化炭素を取り出す技術が実用化されている。
On the other hand, if calcium is eluted from steelmaking slag and recovered in an aqueous solution containing carbon dioxide (hereinafter, also simply referred to as “CO 2 aqueous solution”), it is expected that the above problems due to the use of acid can be solved (See Patent Documents 1 to 3). A large amount of carbon dioxide is contained in the exhaust gas, and after desulfurizing and denitrifying the exhaust gas, a gas which is almost carbon dioxide except air and steam is obtained. Industrially, as shown in Non-Patent Document 4, a technology for extracting carbon dioxide from exhaust gas has been put to practical use.
特許文献１には、転炉スラグ中のカルシウムを溶出させた水溶液に二酸化炭素を吹き込んで、沈殿した炭酸カルシウムを回収する方法が記載されている。このとき、水への溶解性が高い炭酸水素カルシウムの生成を抑制するため、ｐＨは下限値が１０程度に維持される。特許文献１には、ｐＨを１０以上に維持する具体的な方法は記載されていないものの、二酸化炭素の吹込み量を調整することでｐＨを１０以上に維持するものと思われる。
Patent Document 1 describes a method of blowing carbon dioxide into an aqueous solution in which calcium in a converter slag is eluted, and recovering precipitated calcium carbonate. At this time, the lower limit value of pH is maintained at about 10 in order to suppress the formation of calcium hydrogen carbonate having high solubility in water. Although a specific method for maintaining the pH at 10 or more is not described in Patent Document 1, it is considered that the pH is maintained at 10 or more by adjusting the blowing amount of carbon dioxide.
特許文献２には、破砕した製鋼スラグを鉄濃縮相およびリン濃縮相に分離し、リン濃縮相中のＣａ化合物を二酸化炭素を溶解させた洗浄水に溶解させ、その後、洗浄水を５０～６０℃程度に加熱して、洗浄水中の炭酸水素カルシウムを炭酸カルシウムとして沈殿させ、回収する方法が記載されている。
In Patent Document 2, a crushed steelmaking slag is separated into an iron-enriched phase and a phosphorus-enriched phase, and the Ca compound in the phosphorus-enriched phase is dissolved in washing water in which carbon dioxide is dissolved, and then 50 to 60 washing waters. A method is disclosed in which calcium hydrogen carbonate in wash water is precipitated as calcium carbonate by heating to about ° C. and recovered.
特許文献３には、製鋼スラグからＣａ化合物を複数回に分けて溶出させて、回収する方法が記載されている。この方法では、二酸化炭素を吹き込んだ水に製鋼スラグ（予備処理スラグ）を複数回浸漬することで、２ＣａＯ・ＳｉＯ２相およびこの相に固溶したリンが優先的に溶出することが記載されている。
Patent Document 3 describes a method for separating and recovering a Ca compound in multiple steps from a steelmaking slag. In this method, it is described that by immersing steelmaking slag (pretreated slag) a plurality of times in water blown with carbon dioxide, the 2CaO · SiO 2 phase and phosphorus dissolved in this phase are preferentially eluted There is.
一方で、製鋼スラグ内のＦｅは、鉄系酸化物、酸化カルシウム鉄アルミニウム、および極少量ではあるが金属鉄として存在している。これらのうち、鉄系酸化物は、ＭｎまたはＭｇを含有するほか、Ｃａ、Ａｌ、Ｓｉ、Ｐ、Ｔｉ、ＣｒおよびＳなどの元素を少量ながら含有する。また、酸化カルシウム鉄アルミニウムも、Ｓｉ、Ｐ、Ｔｉ、ＣｒおよびＳなどの元素を少量ながら含有する。なお、本明細書においては、鉄系酸化物は空気中の水蒸気などによってその表面の一部などが水酸化物などに変化した化合物も含み、酸化カルシウム鉄アルミニウムも空気中の水蒸気および二酸化炭素などによりその表面の一部などが水酸化物または炭酸化物などに変化した化合物も含む。
On the other hand, Fe in steelmaking slag is present as iron-based oxide, calcium iron aluminum oxide, and metallic iron, although in a very small amount. Among these, the iron-based oxide contains not only Mn or Mg but also a small amount of elements such as Ca, Al, Si, P, Ti, Cr and S. In addition, calcium iron aluminum also contains a small amount of elements such as Si, P, Ti, Cr and S. In the present specification, the iron-based oxide also includes a compound in which a portion of the surface has been converted to a hydroxide or the like by water vapor in the air, and calcium iron aluminum oxide also contains water vapor and carbon dioxide in the air It also includes a compound in which part of its surface has been changed to hydroxide or carbonate by the
上記鉄系酸化物は、その多くがウスタイト系酸化物（ＦｅＯ）として存在し、その他にヘマタイト系酸化物（Ｆｅ２Ｏ３）やマグネタイト系酸化物（Ｆｅ３Ｏ４）としても存在する。
Most of the iron-based oxides exist as wustite-based oxides (FeO), and also exist as hematite-based oxides (Fe 2 O 3 ) and magnetite-based oxides (Fe 3 O 4 ).
これらのうち、ウスタイト系酸化物およびヘマタイト系酸化物は、強磁性体であるマグネタイト系酸化物（Ｆｅ３Ｏ４）がその内部に分散しているため、磁選によって製鋼スラグから分離できる。なお、単独または他の鉄系酸化物と共存するマグネタイト系酸化物も、磁選によって製鋼スラグから分離できる。
Among these, wustite-based oxide and hematite-based oxide can be separated from steelmaking slag by magnetic separation because magnetite-based oxide (Fe 3 O 4 ), which is a ferromagnetic substance, is dispersed therein. In addition, magnetite-based oxides which are present alone or coexist with other iron-based oxides can also be separated from steelmaking slag by magnetic separation.
また、特許文献４～特許文献６には、より多くの鉄系酸化物を磁選によって分離するため、酸化処理などによってウスタイト系酸化物をマグネタイト系酸化物に改質する方法が記載されている。
Further, Patent Documents 4 to 6 describe a method of reforming wustite-based oxides to magnetite-based oxides by oxidation treatment or the like in order to separate more iron-based oxides by magnetic separation.
上記酸化カルシウム鉄アルミニウムは、磁化して磁性体となるため、やはり磁選によって製鋼スラグから分離できる。
Since the calcium iron aluminum is magnetized to become a magnetic body, it can be separated from the steelmaking slag by magnetic separation as well.
鉄系酸化物および酸化カルシウム鉄アルミニウム（以下、これらをまとめて「鉄系化合物」ともいう。酸化カルシウム鉄アルミニウムは、Ｃａ化合物であると同時に鉄系化合物でもある。）は、リンの含有量が０．１質量％以下とわずかであるため、上述した磁選などによって製鋼スラグから分離して回収すれば、高炉や焼結の原料として用いることができる。
Iron-based oxides and calcium-iron-aluminum oxide (hereinafter collectively referred to as "iron-based compound". Calcium-iron-aluminum oxide is a Ca compound and an iron-based compound at the same time.) Since the content is as small as 0.1% by mass or less, it can be used as a material for blast furnace and sintering if it is separated and recovered from steelmaking slag by the above-described magnetic separation and the like.
金属鉄は、製鋼工程でスラグ中に巻き込まれたＦｅや、製鋼スラグの凝固中に析出する微小なＦｅである。金属鉄のうち大きいものは、大気中で製鋼スラグを破砕もしくは粉砕する乾式の工程中で、磁選その他の方法で取り除かれている。
The metallic iron is Fe which is caught in the slag in the steelmaking process, or fine Fe which precipitates out during solidification of the steelmaking slag. Large metallic iron is removed by magnetic separation or other methods in a dry process of crushing or crushing steelmaking slag in the atmosphere.
上述したように、製鋼スラグからカルシウムを回収することによる利点は多いため、製鋼スラグからのカルシウムの回収率をより高めたいという要望は常に存在する。
As mentioned above, there are many advantages to recovering calcium from steelmaking slag, so there is always a desire to increase the recovery of calcium from steelmaking slag.
特許文献１に記載の方法では、二酸化炭素を多く吹込めばｐＨが１０より低くなるし、逆に二酸化炭素の吹込み量を少なくすればカルシウムの析出量は減少する。そのため、カルシウムの回収率を高めようとすると、二酸化炭素の吹込み量を精密に調節する必要があるため、回収工程が煩雑となり、回収コストが高くなってしまう。
In the method described in Patent Document 1, if a large amount of carbon dioxide is blown in, the pH becomes lower than 10, and conversely, if the amount of blown carbon dioxide is reduced, the amount of precipitated calcium decreases. Therefore, in order to increase the calcium recovery rate, it is necessary to precisely adjust the amount of carbon dioxide injected, which complicates the recovery step and increases the recovery cost.
特許文献２に記載の方法では、鉱酸を使用するため、カルシウムを炭酸カルシウムとして析出回収しても、その中に多量の鉱酸、および鉱酸とカルシウムとの塩が含まれており、これらを分離するために多量の水および高温の加熱が必要になる。そのため、特許文献２に記載の方法は、工程が煩雑になり、回収コストが高くなる。なお、二酸化炭素を含有させた洗浄水（炭酸水素カルシウムを含有する水溶液）により製鋼スラグを洗浄してカルシウムを溶解させると、カルシウムが溶解した洗浄水は、炭酸水素カルシウムを含有しているため中性～弱アルカリ性である。この洗浄液と鉱酸で浸出した液とを混合して、鉱酸で浸出した液を中和して炭酸カルシウムを析出させようとすると、鉱酸により混合液が酸性化して、水溶液のカルシウムの溶解量（溶解度）が大きくなる。そのため、炭酸カルシウムが析出しても、混合液中に多量のカルシウムが残存することになり、カルシウムの回収効率は悪くなる。
In the method described in Patent Document 2, since mineral acid is used, even if calcium is precipitated and recovered as calcium carbonate, a large amount of mineral acid and salts of mineral acid and calcium are contained therein, and these A large amount of water and high temperature heating is required to separate the Therefore, in the method described in Patent Document 2, the process becomes complicated and the recovery cost becomes high. When calcium is dissolved by washing steelmaking slag with washing water (aqueous solution containing calcium hydrogen carbonate) containing carbon dioxide, the washing water in which calcium is dissolved contains calcium hydrogen carbonate. It is mild to slightly alkaline. When this washing solution is mixed with a solution leached with mineral acid, and the solution leached with mineral acid is neutralized to precipitate calcium carbonate, the mixture is acidified with mineral acid to dissolve calcium in the aqueous solution. The amount (solubility) increases. Therefore, even if calcium carbonate precipitates, a large amount of calcium remains in the mixed solution, and the calcium recovery efficiency is degraded.
特許文献３に記載の方法では、カルシウムの回収率を高めようとすると、Ｃａ化合物を溶解させる工程の回数をさらに増やす必要が生じる。そのため、回収工程および回収したＣａ化合物を合一させる工程が煩雑となり、回収コストが高くなってしまう。
In the method described in Patent Document 3, in order to increase the recovery rate of calcium, it is necessary to further increase the number of steps of dissolving the Ca compound. Therefore, the recovery step and the step of combining the recovered Ca compounds become complicated, and the recovery cost becomes high.
このように、従来の方法では、カルシウムの回収率を高めようとすると、回収工程が煩雑となるため回収に時間がかかり、回収コストが高くなってしまうという問題があった。これに対し、ＣＯ２水溶液へのＣａ化合物の溶出量を多くすることができれば、カルシウムの回収率を容易に高めることができると思われる。
As described above, in the conventional method, when it is attempted to increase the calcium recovery rate, the recovery step is complicated, so that it takes time for recovery, and there is a problem that the recovery cost becomes high. On the other hand, if the elution amount of the Ca compound in the CO 2 aqueous solution can be increased, it is considered that the recovery rate of calcium can be easily enhanced.
しかし、特許文献１および２には、ＣＯ２水溶液へのＣａ化合物の溶出量を多くするための工夫は何ら示唆されていない。また、特許文献３に記載の方法では、Ｃａ化合物を溶解させる工程の回数を増やせばカルシウムの総溶出量も増えると考えられるが、この方法には、上述したように、工程が煩雑となり、回収コストが高くなってしまうという問題がある。
However, Patent Literatures 1 and 2 do not suggest any device for increasing the elution amount of the Ca compound to the CO 2 aqueous solution. Further, in the method described in Patent Document 3, if the number of steps of dissolving the Ca compound is increased, it is considered that the total elution amount of calcium is also increased, but in this method, as described above, the steps become complicated and recovered. There is a problem that the cost becomes high.
上記の問題に鑑み、本発明は、容易により多量のカルシウムを製鋼スラグからＣＯ２水溶液へ溶出させることができる、製鋼スラグからカルシウムを溶出させる方法、当該製鋼スラグからカルシウムを溶出させる方法を実施できる装置、およびこの方法によって溶出したカルシウムを回収する方法を提供することをその目的とする。
In view of the above problems, the present invention can easily elute more calcium from steelmaking slag from a steelmaking slag into CO 2 aqueous solution, can elute calcium from steelmaking slag and can elute calcium from the steelmaking slag It is an object of the present invention to provide an apparatus and a method of recovering calcium eluted by this method.
上記目的に鑑み、本発明は、粉砕・沈降槽の内部の液面に近い上部側の領域における製鋼スラグを含むスラリーの撹拌を抑制して前記製鋼スラグを沈降させつつ、前記粉砕・沈降槽の内部の底部側の領域で前記スラリーに含まれる製鋼スラグを粉砕または前記製鋼スラグの表面を磨砕する工程と、前記スラリーに二酸化炭素を導入して、前記粉砕または磨砕された製鋼スラグと前記二酸化炭素が溶解した水溶液とを接触させる工程と、を含む、製鋼スラグからカルシウムを溶出させる方法に関する。
In view of the above object, the present invention suppresses the stirring of the slurry containing steelmaking slag in the region on the upper side close to the liquid surface inside the crushing and settling tank while settling the steelmaking slag, while suppressing the stirring of the steelmaking slag. Grinding the steelmaking slag contained in the slurry or grinding the surface of the steelmaking slag in a region on the bottom side of the inner portion, introducing carbon dioxide into the slurry, and grinding or grinding the steelmaking slag and the steelmaking slag; Contacting the carbon dioxide solution with an aqueous solution in which carbon dioxide is dissolved, and a method of eluting calcium from steelmaking slag.
また、本発明は、上記方法により製鋼スラグからカルシウムを溶出させる工程と、前記溶出したカルシウムを回収する工程とを含む、製鋼スラグからカルシウムを回収する方法に関する。
The present invention also relates to a method for recovering calcium from steelmaking slag, which comprises the steps of eluting calcium from steelmaking slag by the above method, and recovering the eluted calcium.
また、本発明は、製鋼スラグを含むスラリーが投入される粉砕・沈降槽と、前記粉砕・沈降槽の内部の底部側の領域に配置され、前記粉砕・沈降槽の内部の液面に近い上部側の領域における前記スラリーの撹拌が抑制されて前記製鋼スラグが沈降するように、前記底部側の領域で前記スラリーに含まれる製鋼スラグを粉砕または前記製鋼スラグの表面を磨砕する粉砕機構と、前記粉砕機構による粉砕または磨砕と同時に、前記スラリーに二酸化炭素を導入する二酸化炭素導入部と、を含む、製鋼スラグからカルシウムを溶出させる装置に関する。
Further, according to the present invention, a grinding / settling tank into which a slurry containing steelmaking slag is charged, and an area on the bottom side inside the grinding / settling tank, and an upper portion close to a liquid surface inside the grinding / settling tank A grinding mechanism for grinding or grinding the surface of the steelmaking slag contained in the slurry in the area on the bottom side so that the stirring of the slurry in the side area is suppressed and the steelmaking slag settles; The present invention relates to an apparatus for eluting calcium from steelmaking slag, including a carbon dioxide introduction unit for introducing carbon dioxide into the slurry simultaneously with grinding or grinding by the grinding mechanism.
本発明によれば、容易により多量のカルシウムを製鋼スラグからＣＯ２水溶液へ溶出させることができる、製鋼スラグからカルシウムを溶出させる方法、当該製鋼スラグからカルシウムを溶出させる方法を実施できる装置、およびこの方法によって溶出したカルシウムを回収する方法が提供される。
According to the present invention, it is possible to easily dissolve a large amount of calcium from steelmaking slag to a CO 2 aqueous solution, a method of eluting calcium from steelmaking slag, an apparatus capable of performing the method of eluting calcium from the steelmaking slag, Methods are provided for recovering eluted calcium.
１．製鋼スラグからカルシウムを溶出させる方法および装置
［第１の実施形態］
本発明に関する製鋼スラグからカルシウムを溶出させる方法および装置の第１の実施形態では、粉砕・沈降槽の内部で製鋼スラグからカルシウムを溶出させる際に、粉砕・沈降槽の内部の底部側の領域でスラリー中の製鋼スラグの粉砕または製鋼スラグの表面の磨砕（以下、これらの粉砕および磨砕をあわせて「粉砕等」ともいう。）を行う。このとき、粉砕・沈降槽の内部の液面に近い上部側の領域では、スラリーの撹拌による流動を抑制して前記製鋼スラグを沈降させる。また、このようにして粉砕等された製鋼スラグとＣＯ２水溶液とを接触させて、製鋼スラグからカルシウムを溶出させる。 1. Method and apparatus for eluting calcium from steelmaking slag [First embodiment]
In the first embodiment of the method and apparatus for eluting calcium from steelmaking slag according to the present invention, when calcium is eluted from steelmaking slag inside the grinding and settling tank, in the region on the bottom side inside the grinding and settling tank Pulverization of the steelmaking slag in the slurry or grinding of the surface of the steelmaking slag (hereinafter, these pulverization and grinding are combined and also referred to as "pulverization etc.") is performed. At this time, in the upper region close to the liquid level inside the crushing and settling tank, the flow of the slurry due to stirring is suppressed to precipitate the steelmaking slag. Further, the steelmaking slag thus crushed and the like is brought into contact with a CO 2 aqueous solution to elute calcium from the steelmaking slag.
［第１の実施形態］
本発明に関する製鋼スラグからカルシウムを溶出させる方法および装置の第１の実施形態では、粉砕・沈降槽の内部で製鋼スラグからカルシウムを溶出させる際に、粉砕・沈降槽の内部の底部側の領域でスラリー中の製鋼スラグの粉砕または製鋼スラグの表面の磨砕（以下、これらの粉砕および磨砕をあわせて「粉砕等」ともいう。）を行う。このとき、粉砕・沈降槽の内部の液面に近い上部側の領域では、スラリーの撹拌による流動を抑制して前記製鋼スラグを沈降させる。また、このようにして粉砕等された製鋼スラグとＣＯ２水溶液とを接触させて、製鋼スラグからカルシウムを溶出させる。 1. Method and apparatus for eluting calcium from steelmaking slag [First embodiment]
In the first embodiment of the method and apparatus for eluting calcium from steelmaking slag according to the present invention, when calcium is eluted from steelmaking slag inside the grinding and settling tank, in the region on the bottom side inside the grinding and settling tank Pulverization of the steelmaking slag in the slurry or grinding of the surface of the steelmaking slag (hereinafter, these pulverization and grinding are combined and also referred to as "pulverization etc.") is performed. At this time, in the upper region close to the liquid level inside the crushing and settling tank, the flow of the slurry due to stirring is suppressed to precipitate the steelmaking slag. Further, the steelmaking slag thus crushed and the like is brought into contact with a CO 2 aqueous solution to elute calcium from the steelmaking slag.
なお、粉砕とは、エネルギーを機械的に対象粒子（製鋼スラグの粒子）に与えて、破壊し、そのサイズを小さくすることである。機械的にエネルギー与える方法には、ボール等の粉砕媒体を動かし、対象粒子と接触させる方法、ローラーやハンマーなど装置の一部が動き、対象粒子と接触させる方法などがある。対象粒子を単に流動させても、対象粒子がスラリーの流れと一緒に移動するのみなので、対象粒子を破壊してそのサイズを減ずるほどのエネルギーを与えることはできない。
Pulverization refers to mechanically giving energy to target particles (particles of steelmaking slag) to break them and reducing their size. As a method of mechanically applying energy, there is a method of moving a grinding medium such as a ball and bringing it into contact with target particles, and a method of making parts of a device such as a roller and a hammer move and make contact with target particles. Simply flowing the particles of interest does not provide enough energy to destroy the particles of interest and reduce their size, as the particles of interest only move with the flow of the slurry.
（製鋼スラグの粉砕等）
上述したように、製鋼スラグ中のカルシウムは、遊離石灰、水酸化カルシウム（Ｃａ（ＯＨ）２）、炭酸カルシウム（ＣａＣＯ３）、ケイ酸カルシウム（Ｃａ２ＳｉＯ４、Ｃａ３ＳｉＯ５）および酸化カルシウム鉄アルミニウム（Ｃａ２（Ａｌ１－ＸＦｅＸ）２Ｏ５）などの形態で存在する。 (Crushing of steelmaking slag etc.)
As described above, calcium in steelmaking slag is free lime, calcium hydroxide (Ca (OH) 2 ), calcium carbonate (CaCO 3 ), calcium silicate (Ca 2 SiO 4 , Ca 3 SiO 5 ) and calcium oxide It exists in a form such as iron aluminum (Ca 2 (Al 1 -x Fe x ) 2 O 5 ).
上述したように、製鋼スラグ中のカルシウムは、遊離石灰、水酸化カルシウム（Ｃａ（ＯＨ）２）、炭酸カルシウム（ＣａＣＯ３）、ケイ酸カルシウム（Ｃａ２ＳｉＯ４、Ｃａ３ＳｉＯ５）および酸化カルシウム鉄アルミニウム（Ｃａ２（Ａｌ１－ＸＦｅＸ）２Ｏ５）などの形態で存在する。 (Crushing of steelmaking slag etc.)
As described above, calcium in steelmaking slag is free lime, calcium hydroxide (Ca (OH) 2 ), calcium carbonate (CaCO 3 ), calcium silicate (Ca 2 SiO 4 , Ca 3 SiO 5 ) and calcium oxide It exists in a form such as iron aluminum (Ca 2 (Al 1 -x Fe x ) 2 O 5 ).
これらのうち、遊離石灰は、ＣＯ２水溶液に溶解しやすいものの、通常、製鋼スラグ中に１０質量％未満程度しか含まれていない。これに対し、ケイ酸カルシウムは、通常、製鋼スラグ中に２５質量％～７０質量％程度含まれ、酸化カルシウム鉄アルミニウムは、通常、製鋼スラグ中に２質量％～３０質量％程度含まれる。そのため、遊離石灰以外のＣａ化合物（ケイ酸カルシウムおよび酸化カルシウム鉄アルミニウムなど）に含まれるカルシウムをＣＯ２水溶液により溶出しやすくすれば、製鋼スラグからＣＯ２水溶液へのカルシウムの溶出量を多くすることができ、製鋼スラグからカルシウムをより短時間で回収することも可能になると考えられる。
Among these, although free lime is easily dissolved in a CO 2 aqueous solution, it is usually contained in the steelmaking slag only at less than about 10% by mass. On the other hand, calcium silicate is generally contained in about 25% by mass to 70% by mass in steelmaking slag, and calcium iron aluminum is usually contained in about 2% by mass to about 30% by mass in steelmaking slag. Therefore, if the calcium contained in Ca compounds other than free lime (such as calcium silicates and calcium oxide iron aluminum) easily eluted with CO 2 aqueous solution, to increase the dissolution of calcium into CO 2 solution from steelmaking slag It is considered possible to recover calcium from steelmaking slag in a shorter time.
しかし、ケイ酸カルシウムおよび酸化カルシウム鉄アルミニウムなどは、通常、ＣＯ２水溶液への溶解速度が遅い。
However, calcium silicate and calcium iron aluminum oxide etc. usually have a slow dissolution rate in CO 2 aqueous solution.
また、カルシウムはＣＯ２水溶液への溶解度が高いが、シリコン、アルミニウムおよび鉄などはＣＯ２水溶液への溶解度が低い。そのため、ケイ酸カルシウムおよび酸化カルシウム鉄アルミニウムがＣＯ２水溶液に溶解するとき、カルシウムは溶出するが、シリコン、アルミニウムおよび鉄などは、水酸化物、炭酸化物または水和物となって製鋼スラグの表面に残存することがある。また、ＣＯ２水溶液への溶解度が低いシリコン、アルミニウムおよび鉄などは、一度溶出した後に製鋼スラグの表面に析出することがある。なお、製鋼スラグ中の酸化鉄や酸化カルシウム鉄アルミニウムなどに含まれる鉄やマンガンなども、溶解度が低い。そのため、上記酸化鉄や酸化カルシウム鉄アルミニウムなどがＣＯ２水溶液にわずかながら溶出するとき、鉄やマンガンなどが製鋼スラグの表面に析出することがある。製鋼スラグの表面に残存または析出したこれらの物質が、ＣＯ２水溶液と製鋼スラグの表面との接触を妨げるため、カルシウムの溶出速度は理想状態よりも遅くなっていると考えられる。
In addition, calcium has high solubility in an aqueous solution of CO 2, but silicon, aluminum, iron and the like have low solubility in an aqueous solution of CO 2 . Therefore, when calcium silicate and calcium iron oxide dissolve in the aqueous solution of CO 2 , calcium elutes, but silicon, aluminum and iron etc. become hydroxide, carbonate or hydrate surface of steel slag May remain in the In addition, silicon, aluminum, iron and the like, which have low solubility in a CO 2 aqueous solution, may precipitate on the surface of steelmaking slag after being eluted once. In addition, iron and manganese contained in iron oxide and calcium iron oxide aluminum in steelmaking slag also have low solubility. Therefore, when the above-mentioned iron oxide or calcium iron oxide aluminum elutes slightly in a CO 2 aqueous solution, iron or manganese may be precipitated on the surface of steelmaking slag. It is thought that the elution rate of calcium is slower than the ideal state because these substances remaining or precipitated on the surface of the steelmaking slag prevent the contact between the CO 2 aqueous solution and the surface of the steelmaking slag.
また、製鋼スラグからのカルシウムの溶出は、製鋼スラグの表面近傍または内部でＣａ化合物と水とが接触することで生じる。ここで、製鋼スラグの内部へもある程度の水は浸透するものの、表面近傍のほうが水との接触量は多い。そのため、カルシウムは、製鋼スラグの表面近傍でより溶出しやすい。また、製鋼スラグに含まれる成分がカルシウムの溶出に使用するＣＯ２水溶液に溶解すると、上述したように、シリコン、アルミニウム、鉄およびマンガンまたはこれらの水酸化物、炭酸化物および水和物などが製鋼スラグの表面に残存または析出することがある。これらの残存または析出した物質が製鋼スラグの内部へのＣＯ２水溶液の浸透を阻害すると、製鋼スラグの内部からはカルシウムが溶出し難くなる。
In addition, the elution of calcium from the steelmaking slag is caused by the contact of the Ca compound and water near or in the surface of the steelmaking slag. Here, although a certain amount of water permeates into the inside of the steelmaking slag, the amount of contact with water is larger in the vicinity of the surface. Therefore, calcium is more likely to be eluted near the surface of the steelmaking slag. Also, when the components contained in steelmaking slag are dissolved in the aqueous solution of CO 2 used for elution of calcium, as described above, silicon, aluminum, iron and manganese or their hydroxides, carbonates and hydrates etc. It may remain or precipitate on the surface of the slag. When these remaining or precipitated substances inhibit the penetration of the aqueous solution of CO 2 into the inside of the steelmaking slag, calcium is less likely to be eluted from the inside of the steelmaking slag.
これに対し、製鋼スラグを粉砕等することで、上記物質が未だ残存または析出していない新たな表面が形成され、この連続的に形成される表面から製鋼スラグの内部までＣＯ２水溶液を浸透させやすくして、製鋼スラグの内部からもカルシウムを溶出させやすくすることができる。また、製鋼スラグを粉砕等することで、粒子状の製鋼スラグ（以下、単に「スラグ粒子」ともいう。なお、単に「製鋼スラグ」というときは、スラグ粒子および粒子状に破砕または粉砕等されていないものの両方を意味する。）の表面積を大きくして、ＣＯ２水溶液とスラグ粒子との接触面積をより大きくすることができる。また、スラグ粒子の表面を摩砕することで、上記残存または析出した物質が除去されて、ＣＯ２水溶液とスラグ粒子との接触面積がより大きくなり、かつ、スラグ粒子の内部にＣＯ２水溶液が浸透しやすくなる。
On the other hand, grinding the steelmaking slag forms a new surface on which the above substance has not yet remained or precipitated, and the CO 2 aqueous solution is allowed to permeate from the continuously formed surface to the inside of the steelmaking slag. By making it easy, calcium can be easily eluted from the inside of the steelmaking slag. In addition, granular steelmaking slag (hereinafter, also simply referred to as "slag particles" by crushing steelmaking slag etc. In addition, when simply referred to as "steelmaking slag", it is crushed or crushed into slag particles and particles). This means that the surface area of CO 2 aqueous solution and slag particles can be made larger by increasing the surface area of both. In addition, by grinding the surface of the slag particles, the remaining or precipitated substance is removed, the contact area between the CO 2 aqueous solution and the slag particles becomes larger, and the CO 2 aqueous solution is contained inside the slag particles. It becomes easy to penetrate.
このとき、製鋼スラグを沈降させつつ、沈降によって製鋼スラグの濃度が高まった底部側の領域で粉砕を行えば、製鋼スラグの濃度が高い状態で、効率よく粉砕等を行うことができる。
At this time, if the grinding is performed in the region on the bottom side where the concentration of the steelmaking slag is increased by sedimentation while settling the steelmaking slag, the grinding and the like can be efficiently performed in a state where the concentration of the steelmaking slag is high.
なお、スラリー中のスラグ粒子は、粒径が大きいほど沈降しやすい。そのため、本実施形態の方法では、粒径が大きいため体積あたりの表面積が小さく、表面からのカルシウムの溶出および内部へのＣＯ２水量液の浸透が生じにくいスラグ粒子は、沈降して粉砕・沈降槽の底部側の領域に移動し、粉砕等され、ＣＯ２水溶液との接触によりカルシウムが溶出しやすい新たな表面が効率的に形成される。粉砕等により粒径が小さくなったスラグ粒子は、浮遊しやすくなり、粉砕・沈降槽の液面方向（上部方向）に移動する。
In addition, the slag particle | grains in a slurry are easy to settle, so that a particle size is large. Therefore, in the method of the present embodiment, since the particle diameter is large, the surface area per volume is small, and the slag particles in which the elution of calcium from the surface and the penetration of the aqueous solution of CO 2 into the inside are difficult to occur are precipitated and crushed and crushed. It moves to the area on the bottom side of the tank, is crushed and the like, and contact with the CO 2 aqueous solution efficiently forms a new surface on which calcium is easily eluted. The slag particles whose particle size has become smaller due to pulverization and the like tend to float and move in the liquid surface direction (upper direction) of the pulverization / settling tank.
上記粉砕等は粉砕・沈降槽の底部側の領域でのみ行われる。そのため、粉砕・沈降槽の上部側の領域では、スラリーの撹拌が抑制されて、スラリーの流動速度が底部側の領域よりも顕著に遅い。つまり、粉砕・沈降槽の上部側の領域では、スラリーの撹拌による流動が抑制されて、製鋼スラグが沈降する。これにより、粉砕・沈降槽の底部側の領域ではスラリー中の製鋼スラグの濃度が高くなり（スラリー中の水の濃度が低くなり）、または沈降した製鋼スラグが底部側の領域に溜まる。こうして製鋼スラグを集めた底部側の領域で粉砕等を行えば、製鋼スラグの粉砕等をより効率的に行える。
The above-mentioned pulverization and the like are performed only in the area on the bottom side of the pulverization / settling tank. Therefore, in the area on the upper side of the crushing and settling tank, the stirring of the slurry is suppressed, and the flow rate of the slurry is significantly slower than the area on the bottom side. That is, in the area | region of the upper side of a crushing / sedimentation tank, the flow by stirring of a slurry is suppressed and steelmaking slag settles. As a result, the concentration of steelmaking slag in the slurry becomes high (the concentration of water in the slurry becomes low) in the region on the bottom side of the crushing and settling tank, or the precipitated steelmaking slag accumulates in the region on the bottom side. Thus, if crushing etc. is performed in the area | region by the side of the bottom part which collected steelmaking slag, grinding etc. of steelmaking slag can be performed more efficiently.
たとえば、製鋼スラグの粉砕等が行われる底部側の領域では、濃度が高い製鋼スラグの粉砕等を効率的に行うため、スラリーの流速を１ｍ／ｍｉｎ以上１００ｍ／ｍｉｎ以下にすることが好ましく、１ｍ／ｍｉｎ以上７０ｍ／ｍｉｎ以下にすることがより好ましい。一方で、製鋼スラグを沈降させる上部側の領域では、スラリーの流速を２０ｍ／ｍｉｎ以下にすることが好ましく、１０ｍ／ｍｉｎ以下にすることがより好ましい。上部側の領域におけるスラリーの流速の下限は、特に限定されないものの、０ｍ／ｍｉｎ（静止状態）とすることができる。また、製鋼スラグを十分に沈降させる観点からは、製鋼スラグの粉砕等が行われない上部側の領域は、高さが０．２ｍ以上であることが好ましく、０．３ｍ以上であることがより好ましく、０．６ｍ以上であることがさらに好ましい。上部側の領域の高さの上限は、特に限定されないものの、５０．０ｍとすることができる。
For example, in the region on the bottom side where crushing of steelmaking slag is performed, it is preferable to set the flow velocity of the slurry to 1 m / min or more and 100 m / min or less, in order to efficiently crush steelmaking slag having a high concentration. It is more preferable to set at least 70 min / min. On the other hand, in the upper region where steelmaking slag is allowed to settle, the flow velocity of the slurry is preferably 20 m / min or less, more preferably 10 m / min or less. Although the lower limit of the flow velocity of the slurry in the upper side region is not particularly limited, it can be 0 m / min (static state). In addition, from the viewpoint of sufficiently settling steelmaking slag, the area on the upper side where crushing or the like of steelmaking slag is not performed preferably has a height of 0.2 m or more, and more preferably 0.3 m or more Preferably, it is more preferably 0.6 m or more. The upper limit of the height of the upper region is not particularly limited, but may be 50.0 m.
一方で、本発明者らの知見によれば、スラリー中のスラグ粒子は、粒径がある程度以下の大きさになると沈降しにくくなる。たとえば、ケイ酸カルシウムの粒子は、粒径が１μｍ以下であるような場合、スラリー中を１ｍ沈降するのに２４時間以上を要する。そのため、上記方法では、ある程度以上に小さくなってＣＯ２水溶液が粒子の内部まで浸透しやすくなり、カルシウムを溶出しやすくなったスラグ粒子は、沈降しにくいので、粉砕・沈降槽の液面に近い上部側に留まりやすい。なお、シリコン、アルミニウム、鉄およびマンガンまたはこれらの水酸化物、炭酸化物および水和物などが表面に析出したスラグ粒子は、粒径が大きくなるため再び沈降し、粉砕等されて表面が新たに露出される。
On the other hand, according to the findings of the present inventors, the slag particles in the slurry are less likely to settle when the particle size is a certain size or less. For example, when particles of calcium silicate have a particle size of 1 μm or less, it takes 24 hours or more to settle 1 m in the slurry. Therefore, in the above method, the slag particles which become smaller than a certain size and the CO 2 aqueous solution easily penetrates to the inside of the particles and which easily dissolves calcium are difficult to settle, so they are close to the liquid surface of the crushing and settling tank Easy to stay on the upper side. In addition, slag particles on the surface of which silicon, aluminum, iron and manganese or their hydroxides, carbonates and hydrates etc. are precipitated are again precipitated due to the large particle size and are crushed and the surface is newly formed. Exposed.
このようにすることで、粒径が大きくカルシウムが溶出しにくいスラグ粒子を優先的に粉砕等し、一方で粒径が小さくカルシウムが溶出しやすいスラグ粒子は粉砕・沈降槽の液面に近い上部側に留まらせてカルシウムを溶出させ続けることができる。そのため、上記方法は、ボールミルなどを用いてスラリー中のスラグ粒子の全体に対して粉砕等を行う場合と比較して、ＣＯ２水溶液との接触による製鋼スラグからのカルシウムの溶出を、より効率的に行うことができる。
In this way, slag particles having a large particle size and having difficulty in eluting calcium are preferentially crushed, etc., while slag particles having a small particle size and in which calcium is easily eluting are closer to the liquid surface of the crushing and settling tank It can stay on the side and keep eluting calcium. Therefore, the above method is more efficient in eluting calcium from steelmaking slag by contact with a CO 2 aqueous solution, as compared with the case where the whole of the slag particles in the slurry is ground or the like using a ball mill or the like. Can be done.
ボールミルなどのようにスラリーとボールを合わせた全体を動かしながら粉砕する湿式粉砕機を用いると、スラリーの全体が撹拌されるため、製鋼スラグは、濃度が低い状態でボールに接触して粉砕等される。そのため、ボールミルなどの湿式粉砕機は、製鋼スラグの粉砕等の効率が悪く、カルシウムの溶出量を多くしにくい。これに対し、スラグ濃度を高くして、ボールミルのような湿式粉砕機にかければ、カルシウムの溶出量を多くできるとも考えられる。しかし、スラグ濃度を高くすると、スラリー中の水の量が相対的に減ることになるので、製鋼スラグから溶出したカルシウムの濃度が水への溶解限度にすぐに達してしまい、製鋼スラグからカルシウムがそれ以上は溶出しにくくなるため、カルシウムの溶出量は多くならない。
If a wet crusher is used to smash while moving the entire combination of the slurry and balls like a ball mill etc., the entire slurry is stirred, so steelmaking slag is contacted with the balls in a low concentration state and crushed Ru. Therefore, a wet crusher such as a ball mill has poor efficiency such as crushing of steelmaking slag, and it is difficult to increase the elution amount of calcium. On the other hand, it is also considered that the elution amount of calcium can be increased by increasing the slag concentration and subjecting it to a wet pulverizer such as a ball mill. However, when the slag concentration is increased, the amount of water in the slurry relatively decreases, so the concentration of calcium eluted from steelmaking slag quickly reaches the solubility limit in water, and calcium from steelmaking slag is Since it becomes difficult to elute more than that, the elution amount of calcium does not increase.
これに対し、容器の内部の液面に近い上部側の領域における製鋼スラグを含むスラリーの撹拌を抑制しながら、容器の内部の底部側で製鋼スラグの粉砕等を行えば、上部側の領域では製鋼スラグを沈降させて、製鋼スラグの濃度が高まった底部側で粉砕等を行えるため、製鋼スラグの粉砕等をより効率的に行える。また、この方法によれば、スラリー中の水の相対量を多くしても、粉砕等の効率が下がることがない。このため、スラリー中の溶出カルシウムの受け皿である水の量を増やすことが可能になり、多くのカルシウムの溶出が可能になる。
On the other hand, if the grinding of steelmaking slag is performed on the bottom side inside the container while suppressing the stirring of the slurry containing steelmaking slag in the region on the upper side close to the liquid level inside the container, the area on the upper side is Since the steelmaking slag is made to settle and crushing can be performed on the bottom side where the concentration of the steelmaking slag is increased, crushing of the steelmaking slag can be performed more efficiently. Moreover, according to this method, the efficiency of pulverization and the like does not decrease even if the relative amount of water in the slurry is increased. Therefore, it is possible to increase the amount of water that is a saucer of eluted calcium in the slurry, and it is possible to dissolve much calcium.
たとえば、本実施形態における、カルシウムの溶出量を高めるためのスラリー中の製鋼スラグの濃度は、製鋼スラグに対する水の割合（水の体積／製鋼スラグの質量）を１０Ｌ／ｋｇ以上とすることができ、３０Ｌ／ｋｇ以上であることが好ましく、５０Ｌ／ｋｇ以上であることがより好ましく、１００Ｌ／ｋｇ以上であることがさらに好ましい。上記割合の上限は、特に限定されないものの、沈降したスラグの粉砕等の効率を高める観点から７００Ｌ／ｋｇ以下とすることができる。
For example, in the present embodiment, the concentration of steelmaking slag in the slurry for increasing the elution amount of calcium can be 10 L / kg or more of the ratio of water to steelmaking slag (volume of water / mass of steelmaking slag) 30 L / kg or more is preferable, 50 L / kg or more is more preferable, and 100 L / kg or more is more preferable. Although the upper limit of the above ratio is not particularly limited, it can be 700 L / kg or less from the viewpoint of enhancing the efficiency such as crushing of settled slag.
上記スラリーは、製鋼スラグを水に懸濁させたものであればよい。二酸化炭素の導入によりＣＯ２水溶液の二酸化炭素濃度を高める時間を短縮して、カルシウムを溶出させるための時間を短縮する観点から、投入されるスラリーは、製鋼スラグをＣＯ２水溶液に懸濁させたものであってもよい。
The said slurry should just be what suspended steelmaking slag in water. From the viewpoint of shortening the time to raise the carbon dioxide concentration of the CO 2 aqueous solution by introducing carbon dioxide and shortening the time to elute calcium, the supplied slurry suspended the steelmaking slag in the CO 2 aqueous solution It may be one.
製鋼スラグの種類は、製鋼工程で排出されるスラグであれば特に限定されない。製鋼スラグの例には、転炉スラグ、予備処理スラグ、二次精錬スラグおよび電気炉スラグが含まれる。
The type of steelmaking slag is not particularly limited as long as it is a slag discharged in the steelmaking process. Examples of steelmaking slag include converter slag, pretreated slag, secondary refining slag and electric furnace slag.
製鋼スラグは、製鋼工程で排出されたものをそのまま使用してもよいが、排出された後に破砕または粉砕（以下、単に「予備破砕」ともいう。）したものを使用してもよい。予備破砕されたスラグ粒子の最大粒径は、１０００μｍ以下であることが好ましい。上記最大粒径が１０００μｍ以下であると、体積あたりの表面積が大きくなり、かつ、製鋼スラグの内部までＣＯ２水溶液が十分に浸透できるため、ＣＯ２水溶液との接触により多量のカルシウムを溶出させることができる。製鋼スラグは、公知の破砕機によって上記範囲まで破砕または粉砕することができる。
Although steelmaking slag may use what was discharged | emitted by the steelmaking process as it is, after discharging | emitting, you may use what crushed or grind | pulverized (Hereinafter, it is also only called "pre-crushing."). The maximum particle size of the pre-crushed slag particles is preferably 1000 μm or less. When the maximum particle size is 1000 μm or less, the surface area per volume is large, and the aqueous solution of CO 2 can sufficiently penetrate into the inside of steelmaking slag, so that a large amount of calcium is eluted by contact with the aqueous solution of CO 2 Can. Steelmaking slag can be crushed or crushed to the above range by a known crusher.
同様の観点からは、スラグ粒子の最大粒径は５００μｍ以下であることが好ましく、２５０μｍ以下であることがより好ましく、１００μｍ以下であることがさらに好ましい。スラグ粒子の最大粒径は、たとえば、破砕または粉砕されたスラグ粒子をハンマーミル、ローラミルおよびボールミルなどを含む粉砕機でさらに粉砕することで、上記範囲まで小さくすることができる。
From the same viewpoint, the maximum particle size of the slag particles is preferably 500 μm or less, more preferably 250 μm or less, and still more preferably 100 μm or less. The maximum particle size of the slag particles can be reduced to the above range by, for example, further crushing the crushed or crushed slag particles with a grinder including a hammer mill, a roller mill, a ball mill and the like.
製鋼スラグは、水が入った容器に製鋼スラグを入れて、遊離石灰と水酸化カルシウムの浸出、およびＣａ化合物の表層のカルシウムの浸出を行った後に、濾過して得られる、濾過残スラグであってもよい。濾過残スラグを使用することにより、カルシウムがある程度溶出したスラグを用いることができるため、本実施形態によってより多量のカルシウムを溶出させるための負荷を軽減できる。
Steelmaking slag is a filtration residue slag obtained by filtering after making steelmaking slag into a container containing water, leaching of free lime and calcium hydroxide, and leaching of calcium on the surface of a Ca compound. May be By using the filtered residual slag, it is possible to use a slag in which calcium is eluted to some extent, so the load for eluting a larger amount of calcium can be reduced by the present embodiment.
このとき同時に得られる、カルシウムが浸出した濾過水（以下、単に「スラグ浸出水」ともいう。）は、ｐＨ１１以上の高アルカリ性の水溶液である。スラグ浸出水は、後述するように、カルシウムを回収する際に、カルシウムを含む固体成分の析出（析出工程）に使用可能である。また、スラグ浸出水は、酸排水の中和剤などのようにアルカリ性水溶液を必要とする用途に活用できる。また、濾過残スラグを用いて後述する含水静置により水和処理を施す場合は、水の混練が不要となるメリットもある。
The filtered water from which calcium is leached (hereinafter, also simply referred to as “slag leachate”), which is obtained simultaneously at this time, is a highly alkaline aqueous solution having a pH of 11 or more. Slag leaching water can be used for precipitation of a calcium-containing solid component (precipitation step), as described later, when recovering calcium. In addition, slag leaching water can be used for applications requiring an alkaline aqueous solution, such as a neutralizing agent for acid wastewater. In addition, there is also a merit that kneading of water is not necessary when the hydration treatment is carried out by holding with water, which will be described later, using filtered residual slag.
製鋼スラグ中のカルシウムを十分に溶出させる観点からは、スラリー中のスラグの量は１ｇ／Ｌ以上１００ｇ／Ｌ以下であることが好ましく、２ｇ／Ｌ以上４０ｇ／Ｌ以下であることがさらに好ましい。
The amount of slag in the slurry is preferably 1 g / L or more and 100 g / L or less, more preferably 2 g / L or more and 40 g / L or less, from the viewpoint of sufficiently eluting calcium in steelmaking slag.
また、製鋼スラグ中のカルシウムを十分に溶出させる観点からは、粉砕・沈降槽中での製鋼スラグの粉砕等は、スラグ粒子の最大粒径が１０００μｍ以下、好ましくは５００μｍ以下、より好ましくは２５０μｍ、さらに好ましくは１００μｍ以下となるまで行うことが好ましい。
In addition, from the viewpoint of sufficiently eluting calcium in steelmaking slag, the crushing of steelmaking slag in the crushing and settling tank has a maximum particle diameter of slag particles of 1000 μm or less, preferably 500 μm or less, more preferably 250 μm, It is more preferable to carry out until it becomes 100 micrometers or less more preferably.
（二酸化炭素の導入）
粉砕等された製鋼スラグは、ＣＯ２水溶液との接触によりカルシウムを溶出する。二酸化炭素は、粉砕・沈降槽に導入される前のスラリーに予め導入されていてもよい。ただし、カルシウムが溶出する際には、カルシウムと二酸化炭素とが反応して水溶性の炭酸水素カルシウムが生成するため、カルシウムの溶解に伴いスラリー中の二酸化炭素は減少する。そのため、カルシウムの溶出効率を高める観点からは、粉砕等と同時、または粉砕等の後にスラリー中に二酸化炭素を導入することが好ましい。特に、粉砕等と同時にスラリー中に二酸化炭素を導入することが好ましく、カルシウムを溶出しやすい新たな面が連続されて形成される、溶出・沈降槽の内部の粉砕等が行われる底部側の領域に、二酸化炭素を導入することが望ましい。なお、底部側の領域に二酸化炭素を導入したときも、導入された二酸化炭素は溶出・沈降槽の上部側の領域にも拡散する。そのため、粉砕等により粒子径が小さくなり、沈降しにくいため上部側の領域に留まったスラグ粒子からも、カルシウムは効率よく溶出されつづける。また、粉砕等により溶出したカルシウムも、上部側の領域にも拡散する。 (Introduction of carbon dioxide)
The crushed steelmaking slag elutes calcium by contact with a CO 2 aqueous solution. Carbon dioxide may be introduced in advance into the slurry before being introduced into the grinding / settling tank. However, when calcium elutes, calcium and carbon dioxide react with each other to form water-soluble calcium hydrogen carbonate, so that carbon dioxide in the slurry decreases as calcium dissolves. Therefore, from the viewpoint of enhancing the elution efficiency of calcium, it is preferable to introduce carbon dioxide into the slurry simultaneously with or after the pulverization and the like. In particular, it is preferable to introduce carbon dioxide into the slurry at the same time as grinding, etc., and a new area where calcium is easily eluted is continuously formed, and the area on the bottom side where the grinding etc. inside the elution / settling tank is performed It is desirable to introduce carbon dioxide. When carbon dioxide is introduced into the bottom region, the introduced carbon dioxide also diffuses into the upper region of the elution / settling tank. As a result, the particle size is reduced due to grinding or the like, and since calcium is difficult to precipitate, calcium is efficiently eluted even from slag particles remaining in the upper region. In addition, calcium eluted by crushing and the like also diffuses to the upper region.
粉砕等された製鋼スラグは、ＣＯ２水溶液との接触によりカルシウムを溶出する。二酸化炭素は、粉砕・沈降槽に導入される前のスラリーに予め導入されていてもよい。ただし、カルシウムが溶出する際には、カルシウムと二酸化炭素とが反応して水溶性の炭酸水素カルシウムが生成するため、カルシウムの溶解に伴いスラリー中の二酸化炭素は減少する。そのため、カルシウムの溶出効率を高める観点からは、粉砕等と同時、または粉砕等の後にスラリー中に二酸化炭素を導入することが好ましい。特に、粉砕等と同時にスラリー中に二酸化炭素を導入することが好ましく、カルシウムを溶出しやすい新たな面が連続されて形成される、溶出・沈降槽の内部の粉砕等が行われる底部側の領域に、二酸化炭素を導入することが望ましい。なお、底部側の領域に二酸化炭素を導入したときも、導入された二酸化炭素は溶出・沈降槽の上部側の領域にも拡散する。そのため、粉砕等により粒子径が小さくなり、沈降しにくいため上部側の領域に留まったスラグ粒子からも、カルシウムは効率よく溶出されつづける。また、粉砕等により溶出したカルシウムも、上部側の領域にも拡散する。 (Introduction of carbon dioxide)
The crushed steelmaking slag elutes calcium by contact with a CO 2 aqueous solution. Carbon dioxide may be introduced in advance into the slurry before being introduced into the grinding / settling tank. However, when calcium elutes, calcium and carbon dioxide react with each other to form water-soluble calcium hydrogen carbonate, so that carbon dioxide in the slurry decreases as calcium dissolves. Therefore, from the viewpoint of enhancing the elution efficiency of calcium, it is preferable to introduce carbon dioxide into the slurry simultaneously with or after the pulverization and the like. In particular, it is preferable to introduce carbon dioxide into the slurry at the same time as grinding, etc., and a new area where calcium is easily eluted is continuously formed, and the area on the bottom side where the grinding etc. inside the elution / settling tank is performed It is desirable to introduce carbon dioxide. When carbon dioxide is introduced into the bottom region, the introduced carbon dioxide also diffuses into the upper region of the elution / settling tank. As a result, the particle size is reduced due to grinding or the like, and since calcium is difficult to precipitate, calcium is efficiently eluted even from slag particles remaining in the upper region. In addition, calcium eluted by crushing and the like also diffuses to the upper region.
二酸化炭素は、たとえば、二酸化炭素を含むガスのバブリング（吹込み）によってスラリーに導入することができる。二酸化炭素の溶解を促進するため、ガスの出口に公知の散気管やマイクロバブル装置などのバブル微細化装置を設け、二酸化炭素のバブル（泡）を小さくすることが好ましい。スラグ粒子からのカルシウムの溶出性を高める観点からは、ＣＯ２水溶液には、３０ｍｇ／Ｌ以上のイオン化していない二酸化炭素（遊離炭酸）が溶解していることが好ましい。なお、一般の水道水中に含まれうる遊離炭酸の量は、３ｍｇ／Ｌ以上２０ｍｇ／Ｌ以下である。
Carbon dioxide can be introduced into the slurry, for example, by bubbling a gas containing carbon dioxide. In order to promote the dissolution of carbon dioxide, it is preferable to provide a bubble refining device such as a known aeration tube or micro bubble device at the outlet of gas to reduce the bubbles (bubbles) of carbon dioxide. From the viewpoint of enhancing the leachability of calcium from slag particles, it is preferable that 30 mg / L or more of non-ionized carbon dioxide (free carbonic acid) be dissolved in the CO 2 aqueous solution. In addition, the quantity of free carbonic acid which may be contained in general tap water is 3 mg / L or more and 20 mg / L or less.
前記二酸化炭素を含むガスは、純粋な二酸化炭素ガスでもよいし、二酸化炭素以外の成分（たとえば、酸素または窒素）を含むガスでもよい。前記二酸化炭素を含むガスの例には、燃焼後の排ガス、ならびに、二酸化炭素、空気および水蒸気の混合ガスが含まれる。ＣＯ２水溶液中の二酸化炭素濃度を高めて、製鋼スラグからＣＯ２水溶液中へのＣａ化合物（ケイ酸カルシウムなど）の溶出性を高める観点からは、前記二酸化炭素を含むガスは、二酸化炭素を高濃度（たとえば、９０％）で含むことが好ましい。以降では二酸化炭素を含むガスを単に二酸化炭素と記載する場合がある。
The gas containing carbon dioxide may be pure carbon dioxide gas, or may be a gas containing components other than carbon dioxide (for example, oxygen or nitrogen). Examples of the gas containing carbon dioxide include exhaust gases after combustion, and a mixed gas of carbon dioxide, air and water vapor. From the viewpoint of increasing the carbon dioxide concentration in the aqueous solution of CO 2 and enhancing the elution of Ca compounds (such as calcium silicate) from steelmaking slag into the aqueous solution of CO 2 , the gas containing carbon dioxide has high carbon dioxide content. It is preferred to include at a concentration (eg, 90%). Hereinafter, a gas containing carbon dioxide may be simply referred to as carbon dioxide.
（装置の構成）
図１は、本実施形態において製鋼スラグからカルシウムを溶出させるために用いる装置の構成を示す模式図である。図１に示す製鋼スラグからカルシウムを溶出させる装置１００は、スラリー（図中網掛け領域）が投入される粉砕・沈降槽１１０と、粉砕・沈降槽１１０の内部の底部側で上記スラリーに含まれる製鋼スラグを粉砕等する粉砕機構１２０と、粉砕・沈降槽１１０の内部に二酸化炭素を導入する二酸化炭素導入部１３０と、を有する。 (Device configuration)
FIG. 1: is a schematic diagram which shows the structure of the apparatus used in order to elute calcium from steelmaking slag in this embodiment. Theapparatus 100 for eluting calcium from the steelmaking slag shown in FIG. 1 is contained in the above-mentioned slurry in the grinding / settling tank 110 into which the slurry (shaded area in the drawing) is charged, and the bottom side inside the grinding / settling tank 110. It has the grinding mechanism 120 which grinds a steelmaking slag etc., and the carbon-dioxide introduction | transduction part 130 which introduce | transduces a carbon dioxide into the inside of the grinding | pulverization / sedimentation tank 110.
図１は、本実施形態において製鋼スラグからカルシウムを溶出させるために用いる装置の構成を示す模式図である。図１に示す製鋼スラグからカルシウムを溶出させる装置１００は、スラリー（図中網掛け領域）が投入される粉砕・沈降槽１１０と、粉砕・沈降槽１１０の内部の底部側で上記スラリーに含まれる製鋼スラグを粉砕等する粉砕機構１２０と、粉砕・沈降槽１１０の内部に二酸化炭素を導入する二酸化炭素導入部１３０と、を有する。 (Device configuration)
FIG. 1: is a schematic diagram which shows the structure of the apparatus used in order to elute calcium from steelmaking slag in this embodiment. The
粉砕・沈降槽１１０は、スラリーが投入される容器である。粉砕・沈降槽１１０は、容器の内部に粉砕機構１２０および二酸化炭素導入部１３０を収容でき、かつ、投入されたスラリーに含まれるスラグ粒子が粉砕機構１２０によって十分に粉砕等できる大きさであればよい。粉砕・沈降槽１１０は、スラリー投入口およびスラリー排出口（いずれも不図示）を有してもよい。
The grinding and settling tank 110 is a container into which the slurry is charged. The grinding / settling tank 110 can accommodate the grinding mechanism 120 and the carbon dioxide introduction unit 130 inside the container, and if the size of the slag particles contained in the input slurry can be sufficiently ground by the grinding mechanism 120 Good. The grinding / settling tank 110 may have a slurry inlet and a slurry outlet (both not shown).
粉砕機構１２０は、粉砕・沈降槽１１０の底部側に配置されて、粉砕・沈降槽１１０の底部側に沈降してきた、スラリー中のスラグ粒子を粉砕等する。これにより、粉砕機構１２０は、スラリー中に粉砕領域を構成する。粉砕機構１２０は、粉砕・沈降槽１１０にスラリーを導入したときのスラリーの液面からの高さ（深さ）が０．２ｍ以上となる位置に配置されることが好ましく、０．３ｍ以上となる位置に配置されることがより好ましく、０．６ｍ以上となる位置に配置されることがさらに好ましい。スラリーの液面からの高さの上限は、特に限定されないものの、２．０ｍとすることができる。液面からの高さを上記範囲にするためには、少なくとも粉砕・沈降槽１１０の内部の上面から粉砕機構１２０の上端までの距離が上記範囲であればよい。
The pulverizing mechanism 120 is disposed on the bottom side of the pulverizing / settling tank 110, and pulverizes slag particles in the slurry that has settled on the bottom side of the pulverizing / settling tank 110. Thereby, the grinding mechanism 120 constitutes a grinding area in the slurry. The crushing mechanism 120 is preferably disposed at a position where the height (depth) of the slurry from the liquid surface when the slurry is introduced into the crushing and settling tank 110 is 0.2 m or more, and 0.3 m or more It is more preferable to arrange in the following position, and it is more preferable to arrange in the position which will be 0.6 m or more. Although the upper limit of the height from the liquid surface of the slurry is not particularly limited, it can be 2.0 m. In order to make the height from the liquid surface in the above range, the distance from at least the upper surface inside the grinding / settling tank 110 to the upper end of the grinding mechanism 120 may be in the above range.
粉砕機構１２０は、粉砕・沈降槽１１０の内部の上部側の領域ではスラリーの撹拌が抑制されて製鋼スラグが沈降するように、スラグ粒子を粉砕等できる構成であればよく、装置１００の構成および粉砕・沈降槽１１０の大きさなどに応じて適宜選択すればよい。
The pulverizing mechanism 120 may have any configuration capable of pulverizing slag particles and the like so that stirring of the slurry is suppressed in the region on the upper side inside the pulverizing / settling tank 110 so that the steelmaking slag settles. It may be appropriately selected according to the size of the crushing and settling tank 110 and the like.
たとえば、粉砕機構１２０は、図１に示すように、粉砕・沈降槽１１０の底部側に投入された粉砕媒体１２２を、撹拌機構１２４で流動させる構成とすることができる。このような構成とすることで、流動された粉砕媒体１２２がスラグ粒子と接触し、かつ、流動されて回転する粉砕媒体１２２がスラグ粒子を摺動して、スラグ粒子をより効率的に粉砕等することができる。
For example, as shown in FIG. 1, the grinding mechanism 120 can be configured to cause the grinding medium 122 introduced to the bottom side of the grinding / settling tank 110 to flow by the stirring mechanism 124. With such a configuration, the fluidized grinding medium 122 is in contact with the slag particles, and the fluidized and rotated grinding medium 122 slides the slag particles, and the slag particles are crushed more efficiently, etc. can do.
粉砕媒体１２２は、スラグ粒子を粉砕等できる材質および大きさを有するものであればよく、ボールミルに用いる公知のボールおよびビーズミルに用いる公知のビーズなどを用いることができる。
The grinding medium 122 may be of any material and size capable of grinding slag particles and the like, and known balls used for a ball mill, known beads used for a bead mill, etc. can be used.
撹拌機構１２４は、粉砕媒体１２２を流動させてスラグ粒子を粉砕等できるものであればよい。たとえば、撹拌機構１２４は、図２Ａに示す複数の撹拌インペラ１２４ａ、および図２Ｂに示す撹拌スクリュー１２４ｂなどとすることができる。これらの撹拌機構１２４は、回転軸体１２４ｃを回転させることで生じる撹拌インペラ１２４ａまたは撹拌スクリュー１２４ｂの回転により粉砕媒体１２２を流動させて、スラグ粒子を粉砕等することができる。また、これらの撹拌機構１２４は、粉砕・沈降槽１１０の内部の底面側に配置され、底面側のみで粉砕媒体１２２を流動させるため、粉砕・沈降槽１１０の内部の上部側の領域への粉砕媒体１２２の移動が抑制されるように、粉砕媒体１２２を流動させることができる。粉砕媒体１２２を流動させやすくし、かつ粉砕媒体１２２の上下動によりスラグ粒子をより粉砕等しやすくする観点からは、それぞれの撹拌インペラ１２４ａは、深さ方向に略直交する方向（以下、単に「水平方向」ともいう。）に対して傾斜して配置されることが好ましい。また、撹拌インペラ１２４ａは、図２Ａに示すように１段のみ配置されてもよいし、粉砕・沈降槽１１０中の異なる深さで粉砕媒体１２２を流動させることができるよう複数段として配置されてもよい。また、回転軸体１２４ｃは、図１に示すように粉砕・沈降槽１１０の液面側から底面側方向に向けて延出してもよいし、後述する図３および図４に示すように粉砕・沈降槽１１０の底面側から液面側方向に向けて延出してもよい。
The stirring mechanism 124 may be any mechanism as long as the grinding medium 122 can be made to flow and the slag particles can be crushed and the like. For example, the stirring mechanism 124 can be a plurality of stirring impellers 124 a shown in FIG. 2A and a stirring screw 124 b shown in FIG. 2B. The stirring mechanism 124 can cause the grinding medium 122 to flow by the rotation of the stirring impeller 124a or the stirring screw 124b generated by rotating the rotating shaft 124c, and the slag particles can be crushed and the like. Further, these stirring mechanisms 124 are disposed on the bottom side inside the grinding / settling tank 110, and the grinding medium 122 is made to flow only on the bottom side, so the grinding to the region on the upper side inside the grinding / settling tank 110 The grinding media 122 can be flowed such that movement of the media 122 is inhibited. In order to facilitate the flow of the grinding medium 122 and to facilitate the crushing and the like of the slag particles by the up and down movement of the grinding medium 122, each stirring impeller 124a has a direction substantially orthogonal to the depth direction (hereinafter simply referred to It is preferable to arrange in an inclined manner with respect to the horizontal direction. In addition, as shown in FIG. 2A, stirring impeller 124a may be disposed only in one stage, or disposed as a plurality of stages so that grinding media 122 can flow at different depths in grinding / settling tank 110. It is also good. The rotary shaft 124c may extend from the liquid surface side of the grinding / settling tank 110 toward the bottom side as shown in FIG. 1, or as shown in FIG. 3 and FIG. It may extend from the bottom side of the settling tank 110 toward the liquid surface side.
なお、図１では粉砕機構１２０はひとつの撹拌機構１２４のみを有するが、粉砕・沈降槽１１０中の水平方向に異なる場所または異なる深さでそれぞれ粉砕媒体１２２を流動させる複数の撹拌機構１２４を有してもよい。
Although in FIG. 1 the pulverizing mechanism 120 has only one stirring mechanism 124, it has a plurality of stirring mechanisms 124 for flowing the grinding medium 122 at different places in the horizontal direction in the crushing / settling tank 110 or at different depths. You may
二酸化炭素導入部１３０は、外部の二酸化炭素供給源と粉砕・沈降槽１１０の内部とを連通する二酸化炭素の流路１３２と粉砕・沈降槽１１０の中に開口する導入口１３４を有し、流路１３２を流通した二酸化炭素を、導入口１３４から粉砕・沈降槽１１０の内部に導入されたスラリーに導入する。なお、二酸化炭素導入部１３０は、二酸化炭素の導入を、粉砕機構１２０による粉砕等と同時に行う。
The carbon dioxide introduction unit 130 has a flow path 132 of carbon dioxide communicating the external carbon dioxide supply source with the inside of the grinding / settling tank 110 and an inlet 134 opened in the grinding / settling tank 110, The carbon dioxide flowing through the passage 132 is introduced into the slurry introduced into the crushing and settling tank 110 from the inlet 134. In addition, the carbon dioxide introduction unit 130 simultaneously performs the introduction of carbon dioxide and the like by the crushing mechanism 120 and the like.
粉砕等された製鋼スラグからカルシウムをより長期間にわたり溶出させやすくする観点からは、導入口１３４は、粉砕機構１２０と同じ深さまたはその近傍の深さになるように配置されることが好ましく、粉砕機構１２０と同じ深さに配置されることがより好ましい。導入口１３４がいずれの位置に配置されても、導入された気体状の二酸化炭素はスラリーの液面方向（上部側方向）に移動しながらＣＯ２水溶液に溶解していくため、粉砕・沈降槽１１０の粉砕機構１２０とそれより液面に近い上部側にスラリーと二酸化炭素とが接触する溶出領域を形成することができる。本実施形態では、導入口１３４はバブル微細化装置である散気管となっており、微細化された二酸化炭素のバブルを粉砕・沈降槽１１０の内部に導入する。
From the viewpoint of facilitating elution of calcium from the crushed steelmaking slag over a longer period of time, the inlet 134 is preferably arranged to have the same depth as the grinding mechanism 120 or a depth near that. More preferably, they are arranged at the same depth as the grinding mechanism 120. Since the introduced gaseous carbon dioxide is dissolved in the aqueous solution of CO 2 while moving in the liquid surface direction (upper side direction) of the slurry regardless of the position where the introduction port 134 is disposed, the pulverization / settling tank An elution region in which the slurry contacts with carbon dioxide can be formed on the grinding mechanism 110 and the upper side closer to the liquid surface. In the present embodiment, the introduction port 134 is a diffusion tube which is a bubble refining device, and introduces the bubbles of the refined carbon dioxide into the inside of the crushing and settling tank 110.
なお、図１では、二酸化炭素導入部１３０は、単一の流路１３２および導入口１３４を有するが、二酸化炭素導入部１３０は、単一の流路またはそれぞれ異なる複数の流路から二酸化炭素をスラリー中に導入する、粉砕・沈降槽１１０中の水平方向の位置または深さが異なる複数の導入口１３４を有してもよい。
In FIG. 1, the carbon dioxide introduction unit 130 has a single flow passage 132 and an introduction port 134, but the carbon dioxide introduction unit 130 may use carbon dioxide from a single flow passage or a plurality of different flow passages. There may be a plurality of inlets 134 of different horizontal positions or depths in the grinding and settling tank 110 introduced into the slurry.
あるいは、二酸化炭素導入部１３０は、撹拌機構１２４からスラリー中に二酸化炭素を導入する構成であってもよい。このような構成とすることで、二酸化炭素導入部１３０は、粉砕機構１２０と同じ深さに二酸化炭素を導入することができるため、粉砕等された直後の、カルシウムを最も溶出させやすい状態の製鋼スラグから、カルシウムを溶出させやすくすることができる。
Alternatively, the carbon dioxide introduction unit 130 may be configured to introduce carbon dioxide into the slurry from the stirring mechanism 124. With such a configuration, the carbon dioxide introducing unit 130 can introduce carbon dioxide to the same depth as the crushing mechanism 120, so steel making in the state in which calcium is most easily eluted immediately after being crushed etc. Calcium can be easily eluted from the slag.
図３は、粉砕機構２２０が有する撹拌機構２２４からスラリー（図中網掛け領域）中に二酸化炭素を導入する二酸化炭素導入部２３０を有する、製鋼スラグからカルシウムを溶出させるために用いる装置２００の構成を示す模式図である。撹拌機構２２４は、粉砕・沈降槽２１０の内部で中空の回転軸体２２４ｃを回転させることで生じる撹拌インペラ２２４ａの回転により粉砕機構２２０が有する粉砕媒体２２２を流動させ、スラグ粒子を粉砕等することができる。また、中空の回転軸体２２４ｃは同時に二酸化炭素導入部２３０の流路２３２としても機能し、先端に設けられた二酸化炭素の導入口２３４からスラリー中に二酸化炭素を導入する。なお、このとき、回転軸体２２４ｃに複数の開口を設けて、先端以外の軸部からもスラリー中に二酸化炭素を導入してもよい。
FIG. 3 shows the configuration of an apparatus 200 used to elute calcium from steelmaking slag, having a carbon dioxide introduction unit 230 for introducing carbon dioxide into the slurry (shaded area in the drawing) from the stirring mechanism 224 of the grinding mechanism 220. FIG. The stirring mechanism 224 causes the grinding medium 222 of the grinding mechanism 220 to flow by the rotation of the stirring impeller 224 a generated by rotating the hollow rotary shaft 224 c inside the grinding / settling tank 210 to grind the slag particles, etc. Can. In addition, the hollow rotary shaft 224c simultaneously functions as the flow path 232 of the carbon dioxide introduction unit 230, and introduces carbon dioxide into the slurry from the carbon dioxide introduction port 234 provided at the tip. At this time, the rotary shaft 224c may be provided with a plurality of openings, and carbon dioxide may be introduced into the slurry from the shaft portion other than the tip.
図４は、粉砕機構３２０が有する撹拌機構３２４からスラリー（図中網掛け領域）中に二酸化炭素を導入する二酸化炭素導入部３３０を有する、製鋼スラグからカルシウムを溶出させるために用いる別の装置３００の構成を示す模式図である。撹拌機構３２４は、中空の回転軸体３２４ｃ、回転軸体３２４ｃから粉砕・沈降槽３１０の水平方向に延出する中空の棒状の撹拌棒支持体３２４ｄ、および撹拌棒支持体３２４ｄから粉砕・沈降槽３１０の深さ方向に延出する棒状の撹拌棒３２４ｅを有する。回転軸体３２４ｃの中空となっている内部と撹拌棒支持体３２４ｄの中空となっている内部とは気体が流通可能に連通しており、撹拌棒支持体３２４ｄは中空となっている内部と外部とを流通可能に連通する導入口３３４を有する。これにより、撹拌機構３２４は、粉砕・沈降槽３１０の内部で中空の回転軸体３２４ｃを回転させることで生じる撹拌棒３２４ｅの回転により粉砕機構３２０が有する粉砕媒体３２２を流動させ、スラグ粒子を粉砕等することができる。また、回転軸体３２４ｃおよび撹拌棒支持体３２４ｄは同時に二酸化炭素導入部３３０の流路３３２としても機能し、撹拌棒支持体３２４ｄが有する導入口３３４からスラリー中に二酸化炭素を導入する。このような構成とすることで、粉砕・沈降槽３１０の内部に投入されたスラリーのより広い範囲に二酸化炭素を導入することができ、粉砕等された製鋼スラグからカルシウムをより長期間にわたり溶出させやすくすることができる。なお、このとき、回転軸体３２４ｃの先端または先端以外の軸部に複数の開口を設けて、これらの開口からもスラリー中に二酸化炭素を導入してもよい。
FIG. 4 shows another apparatus 300 used to elute calcium from steelmaking slag, having a carbon dioxide introduction unit 330 for introducing carbon dioxide into the slurry (the shaded area in the drawing) from the stirring mechanism 324 of the grinding mechanism 320. It is a schematic diagram which shows the structure of. The stirring mechanism 324 includes a hollow rotary shaft 324c, a hollow rod-like stirring rod support 324d extending horizontally from the rotary shaft 324c in the grinding / settling tank 310, and a grinding / settling tank from the stirring rod support 324d. It has a bar-like stirring rod 324 e extending in the depth direction of 310. The hollow interior of the rotary shaft 324c and the hollow interior of the stirring rod support 324d are in fluid communication with each other, and the stirring rod support 324d is hollow interior and exterior And an inlet port 334 in fluid communication therewith. Thereby, the stirring mechanism 324 causes the grinding medium 322 of the grinding mechanism 320 to flow by the rotation of the stirring rod 324e generated by rotating the hollow rotary shaft 324c inside the grinding / settling tank 310, and the slag particles are ground. Etc. Further, the rotating shaft 324c and the stirring rod support 324d simultaneously function as the flow path 332 of the carbon dioxide introducing portion 330, and introduce carbon dioxide into the slurry from the introducing port 334 of the stirring rod support 324d. With such a configuration, carbon dioxide can be introduced into a wider range of the slurry introduced into the crushing and settling tank 310, and calcium is eluted from the crushed steel slag for a longer period of time. It can be made easy. At this time, a plurality of openings may be provided in the tip of the rotary shaft 324c or in a shaft portion other than the tip, and carbon dioxide may be introduced into the slurry also from these openings.
図４において、ひとつの回転軸体３２４ｃから延出する撹拌棒支持体３２４ｄの数、ひとつの撹拌棒支持体３２４ｄから延出する撹拌棒３２４ｅの数、およびひとつの撹拌棒支持体３２４ｄが有する導入口３３４の数は、いずれも特に限定されることなく、１個でも複数でもよいが、粉砕等の効率または製鋼スラグからのカルシウムの溶出しやすさを高める観点からは、いずれも複数であることが好ましい。
In FIG. 4, the number of stir bar supports 324d extending from one rotary shaft 324c, the number of stir bars 324e extending from one stir bar support 324d, and the introduction of one stir bar support 324d. The number of the openings 334 is not particularly limited, and may be one or more, but from the viewpoint of enhancing the efficiency such as crushing or the ease of elution of calcium from the steelmaking slag, all may be more than one. Is preferred.
また、撹拌棒３２４ｅはそれ自体が回転してもよい。このとき、粉砕等の効率を高める観点からは、撹拌棒支持体３２４ｄから複数の撹拌棒３２４ｅが延出する場合は、いずれかの撹拌棒３２４ｄが他とは異なる方向に回転してもよい。
Also, the stirring rod 324e may rotate itself. At this time, from the viewpoint of enhancing the efficiency such as grinding, when a plurality of stirring rods 324e extend from the stirring rod support 324d, one of the stirring rods 324d may rotate in a direction different from the other.
また、撹拌棒３２４ｅは粉砕・沈降槽３１０の深さ方向に伸縮可能な構成であってもよい。このとき、粉砕等の効率を高める観点からは、撹拌棒支持体３２４ｄから複数の撹拌棒３２４ｅが延出する場合は、いずれかの撹拌棒３２４ｅが他とは異なる周期で伸縮してもよい。
In addition, the stirring rod 324e may be configured to be extensible and contractible in the depth direction of the crushing and settling tank 310. At this time, from the viewpoint of enhancing the efficiency such as crushing, when a plurality of stirring rods 324e extend from the stirring rod support 324d, one of the stirring rods 324e may expand and contract in a cycle different from the others.
図５は、二酸化炭素導入部５３０が粉砕・沈降槽の外部に設置された、製鋼スラグからカルシウムを溶出させるために用いる装置５００の構成を示す模式図である。二酸化炭素導入部５３０は、粉砕・沈降槽５１０の内部のスラリーを取り出して粉砕・沈降槽５１０に再度流入させる循環型の流路５３５およびポンプ５３６を有し、流路５３５を流通するスラリーに二酸化炭素を導入する導入口５３４を有する。粉砕・沈降槽５１０からのスラリーの取り出し口と再流入口とは、異なる高さでもよいが、製鋼スラグの沈降を阻害させないため、同じ高さにするのが好ましい。なお、粉砕機構１２０は図１と同様の構成としうるので、詳しい説明は省略する。本実施形態では、スラリーに含まれる製鋼スラグの流動により生じる剪断力で二酸化炭素のバブルが微細化されるため、バブル微細化装置を配置しなくてもよい。
FIG. 5 is a schematic view showing a configuration of an apparatus 500 used for eluting calcium from steelmaking slag, in which a carbon dioxide introduction unit 530 is installed outside the crushing and settling tank. The carbon dioxide introduction unit 530 has a circulation type flow path 535 and a pump 536 for taking out the slurry inside the pulverization / settling tank 510 and re-inflowing into the pulverization / settling tank 510. It has an inlet 534 for introducing carbon. The outlet and re-inlet of the slurry from the grinding / settling tank 510 may have different heights, but preferably have the same height so as not to inhibit the sedimentation of the steelmaking slag. In addition, since the crushing mechanism 120 can be made into the structure similar to FIG. 1, detailed description is abbreviate | omitted. In the present embodiment, bubbles of carbon dioxide are refined by the shear force generated by the flow of steelmaking slag contained in the slurry, so the bubble refining device may not be disposed.
なお、図１～図５に示した装置の構成はあくまで例示であって、本発明の思想の範囲内で様々な変形およびそれぞれの図に示した構成の任意の組み合わせが可能であることはいうまでもない。
It is to be noted that the configuration of the device shown in FIGS. 1 to 5 is merely an example, and various modifications and arbitrary combinations of the configurations shown in the respective drawings are possible within the scope of the spirit of the present invention. It's too late.
たとえば、二酸化炭素導入部は、図１に示すような粉砕・沈降槽の上部側から底面側方向に向けて延出する回転軸体を中空として、その先端、または中空となっている回転軸体の軸部の内部と外部とを流通可能に連通する開口、からスラリーに二酸化炭素を導入する構成であってもよい。このとき、図２Ａおよび図２Ｂにそれぞれ示すような撹拌インペラおよび撹拌スクリューの内部を中空にして、撹拌インペラまたは撹拌スクリューからスラリーに二酸化炭素を導入可能としてもよい。
For example, as shown in FIG. 1, the carbon dioxide introduction portion has a hollow rotary shaft extending from the top side of the crushing / settling tank toward the bottom side, and the rotary shaft has its tip or hollow The carbon dioxide may be introduced into the slurry from an opening that allows the inside and the outside of the shaft portion to flow. At this time, the insides of the stirring impeller and the stirring screw as shown in FIG. 2A and FIG. 2B may be hollow so that carbon dioxide can be introduced into the slurry from the stirring impeller or the stirring screw.
また、二酸化炭素導入部は、図４に示すような撹拌棒の内部を中空にして、その先端、または中空となっている撹拌棒の棒状部の内部と外部とを流通可能に連通する開口、からもスラリーに二酸化炭素を導入可能としてもよい。一方で、図４に示す撹拌棒支持体および撹拌棒からは二酸化炭素をスラリーに導入せず、回転軸体のみからスラリーに二酸化炭素を導入可能としてもよい。
In addition, the carbon dioxide introduction part is an opening that makes the inside of the stirring rod hollow as shown in FIG. 4 and allows the inside or the outside of the rod portion of the hollow stirring rod to flow. It is also possible to introduce carbon dioxide into the slurry. On the other hand, carbon dioxide may not be introduced into the slurry from the stirring rod support and the stirring rod shown in FIG. 4, and carbon dioxide may be introduced into the slurry only from the rotating shaft.
また、図３または図４に示す装置において、二酸化炭素導入部は、撹拌機構から二酸化炭素を導入しつつ、別途設けた二酸化炭素の流路および導入口からも二酸化炭素を導入する構成であってもよい。一方で、図３に示す回転軸体、または図４に示す回転軸体、撹拌棒支持体もしくは撹拌棒からは二酸化炭素を導入せず、別途設けた二酸化炭素の流路および導入口のみから二酸化炭素を導入する構成であってもよい。
Further, in the apparatus shown in FIG. 3 or FIG. 4, the carbon dioxide introducing unit is configured to introduce carbon dioxide from the separately provided flow path and inlet of carbon dioxide while introducing carbon dioxide from the stirring mechanism. It is also good. On the other hand, carbon dioxide is not introduced from the rotating shaft shown in FIG. 3 or the rotating shaft, stirring rod support or stirring rod shown in FIG. It may be configured to introduce carbon.
また、図１、図３および図４に示す装置のように、粉砕・沈降槽の内部でスラリーに二酸化炭素を導入し、かつ、図５に示す装置のように、粉砕・沈降槽の外部でもスラリーに二酸化炭素を導入してもよい。
In addition, carbon dioxide is introduced into the slurry inside the grinding / settling tank as in the apparatus shown in FIGS. 1, 3 and 4, and even outside the grinding / settling tank as in the apparatus shown in FIG. Carbon dioxide may be introduced into the slurry.
なお、攪拌機構の数は、特に限定されることなく、１個でも複数でもよい。このとき、装置が複数の撹拌機構を有するとき、複数の攪拌機構が有するそれぞれの回転軸体は、同じ方向に回転してもよいが、粉砕等の効率をより高めるため、いずれかの回転軸体が他とは異なる方向に回転してもよい。
The number of stirring mechanisms is not particularly limited, and may be one or more. At this time, when the apparatus has a plurality of stirring mechanisms, the respective rotation shafts of the plurality of stirring mechanisms may rotate in the same direction, but in order to further increase the efficiency such as crushing, any rotation shaft The body may rotate in a different direction than the others.
（効果）
本実施形態に係る製鋼スラグからカルシウムを溶出させる方法によれば、Ｃａ溶出方法以外の条件（水／スラグ比など）が同一である場合で比較したときに、製鋼スラグからのＣａ化合物の溶出量がより増えて、製鋼スラグからのカルシウムの回収率がより高まることが期待される。 (effect)
According to the method for eluting calcium from steelmaking slag according to the present embodiment, the amount of Ca compound eluted from steelmaking slag when compared under the same conditions (water / slag ratio etc.) other than the Ca elution method Is expected to increase the recovery of calcium from steelmaking slag.
本実施形態に係る製鋼スラグからカルシウムを溶出させる方法によれば、Ｃａ溶出方法以外の条件（水／スラグ比など）が同一である場合で比較したときに、製鋼スラグからのＣａ化合物の溶出量がより増えて、製鋼スラグからのカルシウムの回収率がより高まることが期待される。 (effect)
According to the method for eluting calcium from steelmaking slag according to the present embodiment, the amount of Ca compound eluted from steelmaking slag when compared under the same conditions (water / slag ratio etc.) other than the Ca elution method Is expected to increase the recovery of calcium from steelmaking slag.
［第２の実施形態］
本発明に関する製鋼スラグからカルシウムを溶出させる方法の第２の実施形態では、上述した第１の実施形態によってカルシウムを溶出させる前に、製鋼スラグを水和処理する。 Second Embodiment
In the second embodiment of the method for eluting calcium from steelmaking slag according to the present invention, the steelmaking slag is subjected to hydration treatment before calcium is eluted according to the first embodiment described above.
本発明に関する製鋼スラグからカルシウムを溶出させる方法の第２の実施形態では、上述した第１の実施形態によってカルシウムを溶出させる前に、製鋼スラグを水和処理する。 Second Embodiment
In the second embodiment of the method for eluting calcium from steelmaking slag according to the present invention, the steelmaking slag is subjected to hydration treatment before calcium is eluted according to the first embodiment described above.
図６は、本実施形態に係る製鋼スラグからカルシウムを溶出させる方法の例示的な工程を示すフローチャートである。本実施形態では、製鋼スラグを水和処理し（工程Ｓ１１０）、その後、上述した第１の実施形態によって製鋼スラグからカルシウムを溶出させる（工程Ｓ１３０）。
FIG. 6 is a flowchart showing an exemplary step of the method of eluting calcium from steelmaking slag according to the present embodiment. In the present embodiment, the steelmaking slag is subjected to a hydration treatment (step S110), and thereafter, calcium is eluted from the steelmaking slag according to the first embodiment described above (step S130).
（水和処理：工程Ｓ１１０）
上述したように、製鋼スラグ中のカルシウムは、遊離石灰、水酸化カルシウム（Ｃａ（ＯＨ）２）、炭酸カルシウム（ＣａＣＯ３）、ケイ酸カルシウム（Ｃａ２ＳｉＯ４、Ｃａ３ＳｉＯ５）および酸化カルシウム鉄アルミニウム（Ｃａ２（Ａｌ１－ＸＦｅＸ）２Ｏ５）などの化合物として存在する。 (Hydration treatment: step S110)
As described above, calcium in steelmaking slag is free lime, calcium hydroxide (Ca (OH) 2 ), calcium carbonate (CaCO 3 ), calcium silicate (Ca 2 SiO 4 , Ca 3 SiO 5 ) and calcium oxide It exists as a compound such as iron aluminum (Ca 2 (Al 1 -x Fe x ) 2 O 5 ).
上述したように、製鋼スラグ中のカルシウムは、遊離石灰、水酸化カルシウム（Ｃａ（ＯＨ）２）、炭酸カルシウム（ＣａＣＯ３）、ケイ酸カルシウム（Ｃａ２ＳｉＯ４、Ｃａ３ＳｉＯ５）および酸化カルシウム鉄アルミニウム（Ｃａ２（Ａｌ１－ＸＦｅＸ）２Ｏ５）などの化合物として存在する。 (Hydration treatment: step S110)
As described above, calcium in steelmaking slag is free lime, calcium hydroxide (Ca (OH) 2 ), calcium carbonate (CaCO 3 ), calcium silicate (Ca 2 SiO 4 , Ca 3 SiO 5 ) and calcium oxide It exists as a compound such as iron aluminum (Ca 2 (Al 1 -x Fe x ) 2 O 5 ).
この製鋼スラグに水和処理を施すと、たとえば、以下の（式１）に示される反応によってケイ酸カルシウムからケイ酸カルシウム水和物と水酸化カルシウム（Ｃａ（ＯＨ）２）が生成したり、以下の（式２）に示される反応によって酸化カルシウム鉄アルミニウムから酸化カルシウム系の水和物が生成したりする（以下、水和処理によって生成し得るカルシウムを含む化合物を総称して「Ｃａ水和物」ともいう。）。
2(2CaO・SiO2) + 4H2O → 3CaO・2SiO2・3H2O + Ca(OH)2 （式１）
2CaO・1/2(Al2O3・Fe2O3) +10H2O → 1/2(4CaO・Al2O3・19H2O) + HFeO2 （式２）
（式（２）は、酸化カルシウム鉄アルミニウム（Ca2(Al1-XFeX)2O5）においてＸ＝１／２の場合の例を示す。） When this steelmaking slag is subjected to a hydration treatment, for example, calcium silicate hydrate and calcium hydroxide (Ca (OH) 2 ) are formed from calcium silicate by the reaction shown in the following (equation 1), A calcium oxide-based hydrate is formed from calcium iron aluminum oxide by the reaction shown in the following (formula 2) (hereinafter, the compound containing calcium which may be produced by hydration treatment is generically referred to as “Ca hydration It is also called "a thing."
2 (2CaO · SiO 2 ) + 4H 2 O → 3CaO · 2SiO 2 · 3H 2 O + Ca (OH) 2 (Formula 1)
2CaO · 1/2 (Al 2 O 3 · Fe 2 O 3) + 10H 2 O → 1/2 (4CaO · Al 2O 3 · 19H 2 O) + HFeO 2 ( Equation 2)
(Formula (2) shows an example in the case of X = 1/2 in calcium iron aluminum oxide (Ca 2 (Al 1 -x Fe x ) 2 O 5 ))
2(2CaO・SiO2) + 4H2O → 3CaO・2SiO2・3H2O + Ca(OH)2 （式１）
2CaO・1/2(Al2O3・Fe2O3) +10H2O → 1/2(4CaO・Al2O3・19H2O) + HFeO2 （式２）
（式（２）は、酸化カルシウム鉄アルミニウム（Ca2(Al1-XFeX)2O5）においてＸ＝１／２の場合の例を示す。） When this steelmaking slag is subjected to a hydration treatment, for example, calcium silicate hydrate and calcium hydroxide (Ca (OH) 2 ) are formed from calcium silicate by the reaction shown in the following (equation 1), A calcium oxide-based hydrate is formed from calcium iron aluminum oxide by the reaction shown in the following (formula 2) (hereinafter, the compound containing calcium which may be produced by hydration treatment is generically referred to as “Ca hydration It is also called "a thing."
2 (2CaO · SiO 2 ) + 4H 2 O → 3CaO · 2SiO 2 · 3H 2 O + Ca (OH) 2 (Formula 1)
2CaO · 1/2 (Al 2 O 3 · Fe 2 O 3) + 10H 2 O → 1/2 (4CaO · Al 2
(Formula (2) shows an example in the case of X = 1/2 in calcium iron aluminum oxide (Ca 2 (Al 1 -x Fe x ) 2 O 5 ))
上記反応などによって生成したＣａ水和物は、ＣＯ２水溶液に溶解しやすい。そのため、水和処理を施すことで、製鋼スラグ中に含まれるケイ酸カルシウムおよび酸化カルシウム鉄アルミニウムなどに由来するカルシウムを、より溶出させやすくなる。
Ca hydrate formed by the above reaction and the like is easily dissolved in a CO 2 aqueous solution. Therefore, the hydration treatment makes it easier to elute calcium derived from calcium silicate and calcium iron oxide aluminum etc. contained in steelmaking slag.
上述したように、遊離石灰は、ＣＯ２水溶液に溶解しやすいものの、通常、製鋼スラグ中に１０質量％未満程度しか含まれていない。これに対し、ケイ酸カルシウムは、通常、製鋼スラグ中に２５質量％～７０質量％程度含まれ、酸化カルシウム鉄アルミニウムは、通常、製鋼スラグ中に２質量％～３０質量％程度含まれる。そのため、水和処理によってケイ酸カルシウムおよび酸化カルシウム鉄アルミニウムなどに含まれるカルシウムをＣＯ２水溶液により溶出しやすくすれば、製鋼スラグからＣＯ２水溶液へのカルシウムの溶出量を多くすることができ、製鋼スラグからカルシウムをより短時間で回収することも可能になると考えられる。
As described above, although free lime is easily dissolved in a CO 2 aqueous solution, it is generally contained in the steelmaking slag only at less than about 10% by mass. On the other hand, calcium silicate is generally contained in about 25% by mass to 70% by mass in steelmaking slag, and calcium iron aluminum is usually contained in about 2% by mass to about 30% by mass in steelmaking slag. Therefore, if calcium contained in calcium silicate and calcium iron oxide is easily eluted by CO 2 aqueous solution by hydration treatment, the elution amount of calcium from steelmaking slag to CO 2 aqueous solution can be increased. It will also be possible to recover calcium from slag in a shorter time.
また、水和処理によって生成する化合物の体積の合計は、通常、反応前の化合物の体積の合計よりも大きくなる。さらには、水和処理中に、製鋼スラグ中の遊離石灰の一部は処理用の水に溶出する。そのため、水和処理を施すと、スラグ粒子の内部にクラックが生じ、このクラックを起点としてスラグ粒子が崩壊しやすい。このようにしてスラグ粒子が崩壊すると、スラグ粒子の粒子径が小さくなって、体積あたりの表面積が大きくなり、かつ、製鋼スラグの内部まで水またはＣＯ２水溶液が十分に浸透できるため、本工程（工程Ｓ１１０）では多くのＣａ化合物を水和することができ、また、カルシウムの溶出工程（工程Ｓ１３０）ではより多量のカルシウムを溶出させることができる。
Also, the sum of the volumes of compounds produced by the hydration treatment will usually be greater than the sum of the volumes of the compounds prior to reaction. Furthermore, during the hydration process, part of the free lime in the steelmaking slag elutes into the water for treatment. Therefore, when the hydration treatment is performed, a crack is generated inside the slag particle, and the slag particle is easily broken starting from the crack. Thus, when the slag particles are disintegrated, the particle diameter of the slag particles is reduced, the surface area per volume is increased, and the water or the CO 2 aqueous solution can sufficiently penetrate to the inside of the steelmaking slag. Many Ca compounds can be hydrated in step S110), and more calcium can be eluted in the calcium elution step (step S130).
水和処理は、製鋼スラグに含まれるＣａ化合物、好ましくはケイ酸カルシウムまたは酸化カルシウム鉄アルミニウム、が水和可能な方法および条件で行えばよい。
The hydration treatment may be performed by a method and conditions under which the Ca compound, preferably calcium silicate or calcium iron aluminum oxide, contained in the steelmaking slag can be hydrated.
水和処理の具体例には、水に浸漬して沈降させた製鋼スラグを静置する処理（以下、単に「浸漬静置」ともいう。）、水に浸漬した製鋼スラグを撹拌または粉砕等する処理（以下、単に「浸漬撹拌等」ともいう。）、水とスラグ粒子とを含むペーストを静置する処理（以下、単に「ペースト化静置」ともいう。）、および十分な量の水蒸気を有する容器の中に製鋼スラグを静置する処理（以下、単に「湿潤静置」ともいう。）などが含まれる。これらの方法によれば、製鋼スラグと水とを十分に接触させることができる。水和処理は、上記浸漬静置、浸漬撹拌等、ペースト化静置および湿潤静置などのうち１種類のみを施してもよいし、これらのうち２種類以上を任意の順番で行ってもよい。スラグ粒子の内部までより十分に水和処理して、カルシウムをより溶出させやすくする観点からは、浸漬撹拌等による水和処理が好ましい。
In a specific example of the hydration treatment, a treatment for settling steelmaking slag immersed in water and settled (hereinafter, also simply referred to as “immersion and standing”), stirring or crushing steelmaking slag immersed in water, etc. Treatment (hereinafter, also simply referred to as “immersion and agitation, etc.”), treatment of leaving a paste containing water and slag particles (hereinafter, also simply referred to as “pasted and settled”), and a sufficient amount of water vapor The processing (hereinafter, also simply referred to as "wet and stand") or the like in which the steelmaking slag is allowed to stand is included in the container having the same. According to these methods, steelmaking slag and water can be brought into sufficient contact. In the hydration treatment, only one of the above-mentioned immersion and standing, immersion and stirring, pastelization and wet and standing, etc. may be applied, or two or more of these may be carried out in any order. . The hydration treatment by immersion stirring or the like is preferable from the viewpoint of making the calcium more easily eluted by performing the hydration treatment sufficiently to the inside of the slag particles.
浸漬撹拌等は、撹拌インペラを有する容器の内部で水に浸漬した製鋼スラグを撹拌してもよいし、上述した第１の実施形態に使用可能な粉砕・沈降槽またはボールミルで製鋼スラグを撹拌しつつ粉砕等してもよい。スラグ粒子の内部までより十分に水和処理して、カルシウムをより溶出させやすくする観点からは、浸漬撹拌等は、製鋼スラグを撹拌しつつ粉砕等することが好ましい。
Immersion stirring etc. may stir steelmaking slag soaked in water inside a container having a stirring impeller, or stir steelmaking slag in a crushing and settling tank or a ball mill usable in the first embodiment described above. It may be crushed while doing so. From the viewpoint of facilitating the elution of calcium more easily by the hydration treatment to the inside of the slag particles, it is preferable to immerse and stir the steelmaking slag while stirring the steelmaking slag.
上述した水和処理による反応は、製鋼スラグの表面近傍または内部でＣａ化合物と水とが接触することで生じる。ここで、製鋼スラグの内部へもある程度の水は浸透するものの、表面近傍のほうが水との接触量は多い。そのため、Ｃａ水和物は、製鋼スラグの表面近傍でより生成しやすい。また、製鋼スラグに含まれる成分が水和処理に使用する水に溶解すると、上述したＣＯ２水溶液へ溶解するときと同様に、Ｆｅ、Ａｌ、ＳｉおよびＭｎまたはこれらの水酸化物、炭酸化物および水和物などが製鋼スラグの表面に残存または析出することがある。これらの残存または析出した物質が製鋼スラグの内部への水の浸透を阻害すると、製鋼スラグの内部ではＣａ水和物が生成しにくくなる。
The reaction by the above-mentioned hydration treatment occurs due to the contact of the Ca compound and water near or inside the surface of the steelmaking slag. Here, although a certain amount of water permeates into the inside of the steelmaking slag, the amount of contact with water is larger in the vicinity of the surface. Therefore, Ca hydrate is more likely to be generated near the surface of steelmaking slag. In addition, when the components contained in steelmaking slag are dissolved in water used for hydration treatment, Fe, Al, Si and Mn or their hydroxides, carbonates, and oxides are dissolved as in the above-mentioned dissolution in CO 2 aqueous solution. Hydrates may remain or precipitate on the surface of steelmaking slag. When these remaining or precipitated substances inhibit the penetration of water into the inside of the steelmaking slag, Ca hydrate is less likely to be formed inside the steelmaking slag.
これに対し、水和処理中に、水に浸漬した製鋼スラグを粉砕等することで、スラグ粒子の表面積を大きくして、水とスラグ粒子との接触面積がより大きくなる。また、水に浸漬した製鋼スラグを粉砕等することで、上記物質が未だ残存または析出していない新たな表面が連続的に形成され、この連続的に形成される表面から製鋼スラグの内部まで水が浸透するため、製鋼スラグの内部でもＣａ水和物がより生成しやすくなる。また、製鋼スラグの表面を磨砕することで、上記残存または析出した物質が除去されて、水とスラグ粒子との接触面積がより大きくなり、かつ、製鋼スラグの内部に水がより浸透しやすくなる。
On the other hand, the surface area of the slag particles is increased by crushing the steelmaking slag immersed in water during the hydration treatment, and the contact area between water and the slag particles is further increased. In addition, by pulverizing steelmaking slag immersed in water, a new surface where the above-mentioned substance has not yet remained or precipitated is continuously formed, and water is continuously formed from the continuously formed surface to the inside of steelmaking slag. As a result, the Ca hydrate is more likely to be formed inside the steelmaking slag. In addition, by grinding the surface of steelmaking slag, the above-mentioned remaining or precipitated substances are removed, the contact area between water and slag particles becomes larger, and water is more likely to penetrate inside steelmaking slag. Become.
水和処理は、第１の実施形態に用いる粉砕・沈降槽とは別の処理装置で行ってもよいが、工程を簡易にする観点からは、第１の実施形態に用いる粉砕・沈降槽の内部または他の湿式粉砕装置での浸漬静置または浸漬撹拌等による水和処理、たとえば、第１の実施形態に用いる粉砕・沈降槽または他の湿式粉砕装置の内部で浸漬撹拌等による水和処理を行ってもよい。このとき、二酸化炭素を導入する以外は第１の実施形態と同様の処理または通常の他の湿式粉砕装置による粉砕と同様の処理を行えば、浸漬撹拌等による水和処理を行うことができる。なお、同一の粉砕・沈降槽の内部で、上記浸漬撹拌等による水和処理と、第１の実施形態によるカルシウムの溶出とを、スラリーを粉砕・沈降槽から排出および粉砕・沈降槽へ再投入を間に挟むことなく行えば、スラリーの移動などが不要となるため、水和およびカルシウムの溶出をより容易に行うことができる。
The hydration treatment may be performed by a processing apparatus different from the grinding / settling tank used in the first embodiment, but from the viewpoint of simplifying the process, the grinding / settling tank used in the first embodiment Hydration treatment by immersion and standing or immersion stirring in an internal or other wet grinding apparatus, for example, hydration treatment by immersion stirring in a grinding / settling tank or other wet grinding apparatus used in the first embodiment You may At this time, if processing similar to that of the first embodiment or processing similar to pulverization by a common other wet pulverizing apparatus is performed except that carbon dioxide is introduced, hydration processing such as immersion stirring can be performed. In the same grinding / settling tank, the above-mentioned hydration treatment by immersion stirring and the like and the elution of calcium according to the first embodiment are discharged from the grinding / settling tank and reloaded into the grinding / settling tank. Since it becomes unnecessary to move the slurry etc. without putting in between, hydration and elution of calcium can be performed more easily.
浸漬静置、浸漬撹拌等またはペースト化静置によって水和処理を施すとき、水和処理に使用する水は、イオン化していない遊離炭酸およびイオン化した炭酸水素イオン（ＨＣＯ３
－）などを含む二酸化炭素の含有量が３００ｍｇ／Ｌ未満であることが好ましい。上記二酸化炭素の含有量が３００ｍｇ／Ｌ未満だと、水和処理に使用する水に遊離石灰、水酸化カルシウム以外のＣａ化合物が溶出しにくいため、製鋼スラグに含まれるカルシウムの大部分をカルシウムの溶出工程でＣＯ２水溶液に溶出させることができ、カルシウムの回収工程が煩雑になりにくい。また、水に二酸化炭素含有量が多いと、遊離石灰や水酸化カルシウムなどから溶出するカルシウムと二酸化炭素とが反応して生成および析出した炭酸カルシウムがスラグ粒子の表面を覆い、水和反応が進み難くなるが、二酸化炭素の含有量が３００ｍｇ／Ｌ未満であると上記炭酸カルシウムの析出による水和反応の阻害が生じにくい。なお、工業用水中の上記二酸化炭素の含有量は、通常、３００ｍｇ／Ｌ未満である。そのため、上記浸漬静置または浸漬撹拌等による水和処理に使用する水は、意図的に二酸化炭素を添加または含有させない工業用水であることが好ましい。
When hydration treatment is carried out by immersion or immersion stirring or pasting or standing, the water used for the hydration treatment is non-ionized free carbon dioxide and ionized bicarbonate ions (HCO 3 − ) etc. The content of carbon is preferably less than 300 mg / L. If the content of carbon dioxide is less than 300 mg / L, it is difficult to elute calcium compounds other than free lime and calcium hydroxide in water used for hydration treatment, so most of the calcium contained in steelmaking slag is calcium It can be eluted in a CO 2 aqueous solution in the elution step, and the calcium recovery step is less likely to be complicated. In addition, when the carbon dioxide content in water is high, calcium and carbon dioxide which are eluted from free lime and calcium hydroxide react with each other to form and precipitate calcium carbonate covering the surface of the slag particles, and the hydration reaction proceeds. Although it becomes difficult, when the content of carbon dioxide is less than 300 mg / L, the inhibition of the hydration reaction due to the precipitation of the calcium carbonate hardly occurs. In addition, content of the said carbon dioxide in industrial water is less than 300 mg / L normally. Therefore, it is preferable that the water used for the hydration process by the said immersion standing or immersion stirring etc. is industrial water which does not make a carbon dioxide add or contain intentionally.
浸漬静置、浸漬撹拌等またはペースト化静置によって水和処理を施すとき、水和処理に使用する水の温度は、水が激しく蒸発しない温度であればよい。たとえば、ほぼ大気圧である条件で製鋼スラグに水和処理を施すときは、水の温度は１００℃以下であることが好ましい。ただし、オートクレーブなどを用いてより高い圧力で水和処理を行うときは、水和処理を行う際の圧力における水の沸点以下である限り、上記水の温度は１００℃以上であってもかまわない。具体的には、浸漬静置または浸漬撹拌等によって水和処理を施すときの水の温度は、０℃以上８０℃以下であることが好ましい。オートクレーブなどを用いてより高い圧力で水和処理を行うときは、温度の上限は特にないが、装置の耐圧性および経済的な面から３００℃以下が好ましい。また、ペースト化静置によって水和処理を施すときの温度は、０℃以上７０℃以下であることが好ましい。
When the hydration treatment is performed by immersion and immersion, immersion and stirring, or paste formation, the temperature of water used for the hydration treatment may be a temperature at which the water does not evaporate violently. For example, when the steelmaking slag is subjected to hydration treatment under the condition of approximately atmospheric pressure, the temperature of water is preferably 100 ° C. or less. However, when the hydration treatment is performed at a higher pressure using an autoclave or the like, the temperature of the water may be 100 ° C. or higher as long as it is equal to or lower than the boiling point of water at the pressure when the hydration treatment is performed. . Specifically, it is preferable that the temperature of the water when the hydration treatment is performed by immersion and standing or immersion stirring is 0 ° C. or more and 80 ° C. or less. When the hydration treatment is performed at a higher pressure using an autoclave or the like, the upper limit of the temperature is not particularly limited, but in view of the pressure resistance of the apparatus and the economical aspect, 300 ° C. or less is preferable. Moreover, it is preferable that the temperature at the time of giving a hydration process by paste formation stationary is 0 degreeC or more and 70 degrees C or less.
水和処理を行う継続時間は、スラグの平均粒子径および水和処理を行う温度（水または水蒸気を含む空気の温度）などによって任意に設定することができる。水和処理を行う継続時間は、スラグの平均粒子径が小さいほど短時間でよく、また、水和処理を行う温度が高いほど短時間でよい。
The duration of the hydration treatment can be optionally set depending on the average particle diameter of the slag and the temperature (the temperature of the air containing water or water vapor) for the hydration treatment. The duration of the hydration treatment may be shorter as the average particle diameter of the slag is smaller, and may be shorter as the temperature at which the hydration treatment is performed is higher.
たとえば、スラグ粒子の最大粒径が１０００μｍ以下である製鋼スラグに浸漬静置または浸漬撹拌等による水和処理を常温で施すときは、水和処理の継続時間は連続して８時間程度とすることができ、３時間以上３０時間以下とすることが好ましい。上記水和処理を４０℃以上７０℃以下の水への浸漬によって施すときは、水和処理の継続時間は連続して０．６時間以上８時間以下とすることが好ましい。
For example, when the hydration treatment by immersion and standing or immersion agitation is performed at ordinary temperature on steelmaking slag in which the maximum particle size of slag particles is 1000 μm or less, the duration of the hydration treatment should be about 8 hours continuously. And preferably 3 hours to 30 hours. When the above hydration treatment is performed by immersion in water at 40 ° C. or more and 70 ° C. or less, the duration of the hydration treatment is preferably continuously 0.6 hours or more and 8 hours or less.
また、スラグ粒子の最大粒径が１０００μｍ以下である製鋼スラグに粉砕等しながらの浸漬撹拌等による水和処理を常温で施すときは、水和処理の継続時間は連続して０．１時間以上５時間以下とすることが好ましく、０．２時間以上３時間以下とすることがより好ましい。あるいは、粉砕等しながらの浸漬撹拌等による水和処理を常温で施すときは、水和処理の継続時間はスラグ粒子の最大粒径が１０００μｍ以下、好ましくは５００μｍ以下、より好ましくは２５０μｍ、さらに好ましくは１００μｍ以下となるまで行うことが好ましい。
In addition, when the hydration treatment by immersion stirring etc. while grinding etc. is performed at room temperature to steelmaking slag having the maximum particle size of 1000 μm or less of slag particles, the duration of the hydration treatment is continuously 0.1 hour or more It is preferable to set it as 5 hours or less, and it is more preferable to set it as 0.2 hours or more and 3 hours or less. Alternatively, when hydration treatment by immersion stirring or the like while grinding is performed at normal temperature, the duration of the hydration treatment is such that the maximum particle diameter of the slag particles is 1000 μm or less, preferably 500 μm or less, more preferably 250 μm, more preferably It is preferable to carry out until 100 μm or less.
また、水和処理は、ケイ酸カルシウムが十分に水和物と水酸化カルシウムになるか、またはおよび酸化カルシウム鉄アルミニウムが十分に酸化カルシウム系の水和物になる程度に行うことが好ましい。たとえば、水和処理は、製鋼スラグに含まれるケイ酸カルシウムの量が５０質量％以下になるまで、もしくは酸化カルシウム鉄アルミニウムの量が２０質量％以下になるまで、施すことが好ましい。
The hydration treatment is preferably carried out to such an extent that calcium silicate is sufficiently hydrated and calcium hydroxide, or calcium iron oxide is sufficiently hydrated to be calcium oxide-based. For example, the hydration treatment is preferably performed until the amount of calcium silicate contained in the steelmaking slag is 50% by mass or less, or the amount of calcium iron aluminum oxide is 20% by mass or less.
（効果）
第２の実施形態によれば、製鋼スラグに含まれるＣａ化合物、特にはケイ酸カルシウムおよび酸化カルシウム鉄アルミニウム、を水和させて、よりＣＯ２水溶液に溶出しやすいＣａ水和物にすることができるため、より短時間でより多量のカルシウムをＣＯ２水溶液に溶出させることができる。また、第２の実施形態における水和処理は、容易に行うことができるため、実施する際のコストの負担が少ない。 (effect)
According to the second embodiment, the Ca compound contained in the steelmaking slag, in particular calcium silicate and calcium iron oxide, is hydrated to be Ca hydrate which is more easily eluted in the CO 2 aqueous solution. Because it is possible, more calcium can be eluted into the aqueous solution of CO 2 in a shorter time. In addition, the hydration process in the second embodiment can be easily performed, so the burden of costs at the time of implementation is small.
第２の実施形態によれば、製鋼スラグに含まれるＣａ化合物、特にはケイ酸カルシウムおよび酸化カルシウム鉄アルミニウム、を水和させて、よりＣＯ２水溶液に溶出しやすいＣａ水和物にすることができるため、より短時間でより多量のカルシウムをＣＯ２水溶液に溶出させることができる。また、第２の実施形態における水和処理は、容易に行うことができるため、実施する際のコストの負担が少ない。 (effect)
According to the second embodiment, the Ca compound contained in the steelmaking slag, in particular calcium silicate and calcium iron oxide, is hydrated to be Ca hydrate which is more easily eluted in the CO 2 aqueous solution. Because it is possible, more calcium can be eluted into the aqueous solution of CO 2 in a shorter time. In addition, the hydration process in the second embodiment can be easily performed, so the burden of costs at the time of implementation is small.
［第３の実施形態］
本発明に関する製鋼スラグからカルシウムを溶出させる方法の第３の実施形態では、上述した第１の実施形態によってカルシウムを溶出させる前に、製鋼スラグに磁選を施す。 Third Embodiment
In the third embodiment of the method for eluting calcium from steelmaking slag according to the present invention, the steelmaking slag is subjected to magnetic separation before the calcium is eluted according to the first embodiment described above.
本発明に関する製鋼スラグからカルシウムを溶出させる方法の第３の実施形態では、上述した第１の実施形態によってカルシウムを溶出させる前に、製鋼スラグに磁選を施す。 Third Embodiment
In the third embodiment of the method for eluting calcium from steelmaking slag according to the present invention, the steelmaking slag is subjected to magnetic separation before the calcium is eluted according to the first embodiment described above.
図７は、本実施形態に係る製鋼スラグからカルシウムを溶出させる方法の例示的な工程を示すフローチャートである。本実施形態では、製鋼スラグに磁選を施し（工程Ｓ１２０）、その後、上述した第１の実施形態によって製鋼スラグからカルシウムを溶出させる（工程Ｓ１３０）。
FIG. 7 is a flow chart showing an exemplary process of the method for eluting calcium from steelmaking slag according to the present embodiment. In the present embodiment, the steelmaking slag is subjected to magnetic separation (step S120), and thereafter, calcium is eluted from the steelmaking slag according to the first embodiment described above (step S130).
（磁選：工程Ｓ１２０）
磁選は、公知の磁力選別機を用いて施すことができる。磁力選別機は、乾式でもよく湿式でもよく、製鋼スラグの状態（乾燥した状態かスラリー状か）によって選択できる。また、磁力選別機は、ドラム式、ベルト式および固定磁石間流動式などから適宜選択できるが、特にスラリーに含まれる製鋼スラグの選別が容易であり、かつ、磁力を高めて磁選量を多くしやすいことから、ドラム式が好ましい。また、磁力選別機が用いる磁石は、永久磁石でもよいし、電磁石でもよい。 (Magnetic selection: Step S120)
Magnetic separation can be performed using a known magnetic separator. The magnetic separator may be either dry or wet, and can be selected according to the state of the steelmaking slag (whether dry or slurry). The magnetic separator can be appropriately selected from a drum type, a belt type, a flow type between fixed magnets, etc. In particular, it is easy to sort steelmaking slag contained in the slurry, and the magnetic force is increased to increase the magnetic separation amount. A drum type is preferable because it is easy. The magnet used by the magnetic separator may be a permanent magnet or an electromagnet.
磁選は、公知の磁力選別機を用いて施すことができる。磁力選別機は、乾式でもよく湿式でもよく、製鋼スラグの状態（乾燥した状態かスラリー状か）によって選択できる。また、磁力選別機は、ドラム式、ベルト式および固定磁石間流動式などから適宜選択できるが、特にスラリーに含まれる製鋼スラグの選別が容易であり、かつ、磁力を高めて磁選量を多くしやすいことから、ドラム式が好ましい。また、磁力選別機が用いる磁石は、永久磁石でもよいし、電磁石でもよい。 (Magnetic selection: Step S120)
Magnetic separation can be performed using a known magnetic separator. The magnetic separator may be either dry or wet, and can be selected according to the state of the steelmaking slag (whether dry or slurry). The magnetic separator can be appropriately selected from a drum type, a belt type, a flow type between fixed magnets, etc. In particular, it is easy to sort steelmaking slag contained in the slurry, and the magnetic force is increased to increase the magnetic separation amount. A drum type is preferable because it is easy. The magnet used by the magnetic separator may be a permanent magnet or an electromagnet.
磁石による磁束密度は、製鋼スラグに含まれる他の化合物から鉄系化合物および金属鉄を選択的に捕捉できる程度であればよく、たとえば、０．００３Ｔ以上０．５Ｔ以下とすることができ、０．００５Ｔ以上０．３Ｔ以下とすることが好ましく、０．０１Ｔ以上０．１５Ｔ以下とすることがより好ましい。
The magnetic flux density by the magnet may be such that it can selectively capture iron-based compounds and metallic iron from other compounds contained in steelmaking slag, and can be, for example, 0.003 T or more and 0.5 T or less, 0 It is preferable to set it to .005T or more and 0.3T or less, and it is more preferable to set it to 0.01T or more and 0.15T or less.
また、磁選は、製鋼スラグに含まれる鉄系化合物の全てを取り除くまで施す必要はない。磁選で製鋼スラグから取り除かれる鉄系化合物の量が少量であっても、従来よりもＣＯ２水溶液にカルシウムが溶出されやすくなるという本発明の効果は奏される。そのため、磁選の時間および回数などは、磁選が製造コストに与える影響などに応じて、適宜選択してもよい。
In addition, magnetic separation does not have to be applied until all of the iron-based compounds contained in the steelmaking slag are removed. Even if the amount of the iron-based compound removed from the steelmaking slag by magnetic separation is small, the effect of the present invention is exhibited that calcium is more easily eluted in the aqueous CO 2 solution than in the prior art. Therefore, the time and the number of times of magnetic separation may be selected appropriately according to the influence of the magnetic selection on the manufacturing cost.
なお、製鋼スラグは、磁選を施す前に、加熱処理されることが好ましい。製鋼スラグを加熱処理すると、鉄系化合物および金属鉄の磁化が高まり、磁選によってより多量の鉄系化合物を取り除くことができる。上記加熱処理は、３００℃以上１０００℃以下で０．０１分以上６０分以下行うことが好ましい。
In addition, it is preferable to heat-process steel-making slag, before giving magnetic selection. When the steelmaking slag is heat-treated, the magnetization of the iron-based compound and the metallic iron is increased, and a larger amount of iron-based compound can be removed by magnetic separation. The heat treatment is preferably performed at 300 ° C. or more and 1000 ° C. or less for 0.01 minutes or more and 60 minutes or less.
製鋼スラグは、磁選時に、乾燥した状態であってもよいが、水に分散したスラリー状であることが好ましい。スラリー状である製鋼スラグは、水分子の極性や水流などによってスラグ粒子が分散しやすいため、鉄系化合物および金属鉄を磁力によって選択的に捕捉しやすい。特にスラグ粒子の粒径が１０００μｍ以下であるとき、空気などの気体中では、大気中の水蒸気の凝縮による液架橋力、スラグ粒子間のファンデルワールス力、スラグ粒子間の静電気力などによりスラグ粒子が凝集しやすいが、スラリー状とすることでスラグ粒子を十分に分散させることができる。また、製鋼スラグ中の金属鉄は微小であるため製鋼スラグが乾燥していると捕捉しにくいが、製鋼スラグをスラリー状にすると、水中に分散した金属鉄も磁選により捕捉しやすくなる。
The steelmaking slag may be in a dry state at the time of magnetic separation, but is preferably in the form of a slurry dispersed in water. In the slurry-like steelmaking slag, since the slag particles are easily dispersed due to the polarity of water molecules, water flow and the like, it is easy to selectively capture the iron-based compound and the metallic iron by the magnetic force. In particular, when the particle size of the slag particles is 1000 μm or less, in a gas such as air, the slag particles are caused by the liquid cross-linking ability by condensation of water vapor in the atmosphere, the van der Waals force between the slag particles, the electrostatic force between the slag particles Although they tend to aggregate, the slurry particles can sufficiently disperse the slag particles. In addition, although metallic iron in steelmaking slag is minute, it is difficult to capture it when the steelmaking slag is dry, but when the steelmaking slag is made slurry, metallic iron dispersed in water also becomes easy to be trapped by magnetic separation.
磁選によって鉄系化合物および金属鉄を取り除いた後のスラリーは、そのまま第１の実施形態によるカルシウムの溶出に用いてもよいが、製鋼スラグがスラリー状であるときは、固液分離して製鋼スラグと液体成分とを分離することが好ましい。固液分離は、減圧濾過および加圧濾過を含む公知の方法で行うことができる。上記固液分離によって得られた液体成分（以下、単に「磁選水」ともいう。）は、スラリー化に用いた水に加えて製鋼スラグから溶出したカルシウムを含むため、アルカリ性となっている。そのため、後述する、製鋼スラグと接触したカルシウムを溶出させた後のＣＯ２水溶液からカルシウムを析出させる際に、ＣＯ２水溶液のｐＨを高めるために上記液体成分を用いることができる。
The slurry after removing the iron-based compound and metallic iron by magnetic separation may be used as it is for elution of calcium according to the first embodiment, but when the steelmaking slag is in a slurry form, solid-liquid separation is performed to make the steelmaking slag. It is preferable to separate the liquid and the liquid component. Solid-liquid separation can be performed by known methods including vacuum filtration and pressure filtration. The liquid component obtained by the above solid-liquid separation (hereinafter, also simply referred to as "magnetic water separation") is alkaline because it contains calcium eluted from steelmaking slag in addition to water used for slurrying. Therefore, it is possible to use the liquid component to increase the pH of when precipitating calcium from CO 2 aqueous solution after elution of calcium in contact with later-described, steelmaking slag, CO 2 solution.
また、磁選によって製鋼スラグから取り除かれた磁選除去スラグは、上述のように鉄系化合物および金属鉄などのＦｅを含む化合物を多く含むため、高炉や焼結の原料として再利用することができる。
In addition, since the magnetic separation removal slag removed from the steelmaking slag by magnetic separation contains a large amount of iron-based compounds and compounds containing Fe such as metallic iron as described above, it can be reused as a raw material for blast furnace and sintering.
なお、水和処理（第２の実施形態）および磁選（第３の実施形態）は、これらを行う場合、いずれか一方のみを行ってもよいし、両方を行ってもよい。これらの両方を行う場合、水和処理および磁選のいずれを先に行ってもよいし、湿式による磁選を行ったり、湿式による磁選を施すスラリーを循環させたりして、両方を同時に行ってもよい。これらのいずれかを先に行う場合、水和処理（特に浸漬撹拌による水和処理）を先に行い、その後に磁選を行うと、特に装置を大型化したときに、カルシウムの回収率がより高まるほか、より短時間で全体の処理を行うことができる。
When the hydration treatment (second embodiment) and the magnetic separation (third embodiment) are performed, either one or both may be performed. When both of these are performed, either of the hydration treatment and the magnetic separation may be performed first, or both of the wet magnetic separation and the wet magnetic separation may be simultaneously performed. . When any of these is performed first, hydration treatment (in particular, hydration treatment by immersion stirring) is performed first, and then magnetic separation is performed, whereby the recovery rate of calcium is further increased, particularly when the device is enlarged. Besides, the whole processing can be performed in a shorter time.
（効果）
第３の実施形態によれば、製鋼スラグの表面に残存または析出した鉄を含む化合物による、上述したＣＯ２水溶液と製鋼スラグの表面との接触の阻害や、比較的硬度が高い鉄を含む化合物による粉砕または摩砕の阻害などを抑制し、製鋼スラグ中のＣａをＣＯ２水溶液により溶出させやすくできると考えられる。 (effect)
According to the third embodiment, the compound containing iron remaining or precipitated on the surface of steelmaking slag inhibits the contact between the above-mentioned CO 2 aqueous solution and the surface of steelmaking slag, and the compound containing iron having a relatively high hardness It is considered that the inhibition of the grinding or grinding due to the above can be suppressed, and the Ca in the steelmaking slag can be easily eluted by the aqueous solution of CO 2 .
第３の実施形態によれば、製鋼スラグの表面に残存または析出した鉄を含む化合物による、上述したＣＯ２水溶液と製鋼スラグの表面との接触の阻害や、比較的硬度が高い鉄を含む化合物による粉砕または摩砕の阻害などを抑制し、製鋼スラグ中のＣａをＣＯ２水溶液により溶出させやすくできると考えられる。 (effect)
According to the third embodiment, the compound containing iron remaining or precipitated on the surface of steelmaking slag inhibits the contact between the above-mentioned CO 2 aqueous solution and the surface of steelmaking slag, and the compound containing iron having a relatively high hardness It is considered that the inhibition of the grinding or grinding due to the above can be suppressed, and the Ca in the steelmaking slag can be easily eluted by the aqueous solution of CO 2 .
また、第３の実施形態によれば、製鋼スラグ中に含まれる酸化カルシウム鉄アルミニウムは、ＣＯ２水溶液との接触によりＣａが溶出した後は磁化しにくくなり、磁選での回収が容易ではない。これに対し、ＣＯ２水溶液との接触前に磁選を施すことで、製鋼スラグ中の酸化カルシウム鉄アルミニウムも回収でき、酸化カルシウム鉄アルミニウムに由来する鉄もより容易に再利用可能となると考えられる。
Moreover, according to the third embodiment, calcium iron aluminum contained in steelmaking slag is difficult to be magnetized after Ca is eluted by contact with a CO 2 aqueous solution, and recovery by magnetic separation is not easy. On the other hand, it is thought that calcium iron aluminum oxide in steelmaking slag can also be recovered by performing magnetic separation prior to contact with a CO 2 aqueous solution, and iron derived from calcium iron aluminum can also be reused more easily.
２．製鋼スラグからカルシウムを回収する方法
図８は、本発明に関する製鋼スラグからカルシウムを回収する方法のフローチャートである。図８に示されるように、本方法は、カルシウムを溶出させる工程（工程Ｓ１００）およびカルシウムを回収する工程（工程Ｓ２００）を含む。 2. Method of Recovering Calcium from Steelmaking Slag FIG. 8 is a flow chart of a method of recovering calcium from steelmaking slag according to the present invention. As shown in FIG. 8, the method includes the steps of eluting calcium (step S100) and recovering calcium (step S200).
図８は、本発明に関する製鋼スラグからカルシウムを回収する方法のフローチャートである。図８に示されるように、本方法は、カルシウムを溶出させる工程（工程Ｓ１００）およびカルシウムを回収する工程（工程Ｓ２００）を含む。 2. Method of Recovering Calcium from Steelmaking Slag FIG. 8 is a flow chart of a method of recovering calcium from steelmaking slag according to the present invention. As shown in FIG. 8, the method includes the steps of eluting calcium (step S100) and recovering calcium (step S200).
［カルシウムを溶出させる工程］
カルシウムを溶出させる工程（工程Ｓ１００）では、製鋼スラグからカルシウムを溶出させる。カルシウムの溶出は、上述した第１の実施形態～第３の実施形態として記載した方法によって行えばよい。 [Step to elute calcium]
In the step of eluting calcium (step S100), calcium is eluted from steelmaking slag. The elution of calcium may be carried out by the methods described as the first to third embodiments described above.
カルシウムを溶出させる工程（工程Ｓ１００）では、製鋼スラグからカルシウムを溶出させる。カルシウムの溶出は、上述した第１の実施形態～第３の実施形態として記載した方法によって行えばよい。 [Step to elute calcium]
In the step of eluting calcium (step S100), calcium is eluted from steelmaking slag. The elution of calcium may be carried out by the methods described as the first to third embodiments described above.
製鋼スラグからカルシウムを溶出させた後のスラリーは、カルシウムの溶出が行われた粉砕・沈降槽とは別の容器に移されて、カルシウムの回収（工程Ｓ２００）が行われるが、回収が顕著に困難とならない限りにおいて、カルシウムの溶出が行われた粉砕・沈降槽でカルシウムの回収（工程Ｓ２００）が行われてもよい。
The slurry after elution of calcium from steelmaking slag is transferred to a separate container from the grinding / settling tank where the elution of calcium was performed, and recovery of calcium (step S200) is performed, but recovery is remarkable. Recovery of calcium (step S200) may be performed in a grinding / settling tank in which elution of calcium has been performed unless it becomes difficult.
［カルシウムを回収する工程］
図９は、カルシウムを回収する工程（工程Ｓ２００）の一例を示すフローチャートである。図９に示されるように、カルシウムを回収する工程（工程Ｓ２００）は、たとえば、製鋼スラグとＣＯ２水溶液とを分離する工程（工程Ｓ２１０：以下、「分離工程」ともいう。）、カルシウムを析出させる工程（工程Ｓ２２０：以下、「析出工程」ともいう。）、および析出した固体成分を回収する工程（工程Ｓ２３０：以下、「回収工程」ともいう。）、などを含むことができる。 [Step of recovering calcium]
FIG. 9 is a flow chart showing an example of the step of recovering calcium (step S200). As shown in FIG. 9, the step of recovering calcium (step S200) is, for example, a step of separating steelmaking slag and a CO 2 aqueous solution (step S210: hereinafter, also referred to as "separation step"), calcium is precipitated. Step S220 (hereinafter, also referred to as "precipitation step"), and a step of recovering the precipitated solid component (step S230: hereinafter, also referred to as "recovery step"), and the like can be included.
図９は、カルシウムを回収する工程（工程Ｓ２００）の一例を示すフローチャートである。図９に示されるように、カルシウムを回収する工程（工程Ｓ２００）は、たとえば、製鋼スラグとＣＯ２水溶液とを分離する工程（工程Ｓ２１０：以下、「分離工程」ともいう。）、カルシウムを析出させる工程（工程Ｓ２２０：以下、「析出工程」ともいう。）、および析出した固体成分を回収する工程（工程Ｓ２３０：以下、「回収工程」ともいう。）、などを含むことができる。 [Step of recovering calcium]
FIG. 9 is a flow chart showing an example of the step of recovering calcium (step S200). As shown in FIG. 9, the step of recovering calcium (step S200) is, for example, a step of separating steelmaking slag and a CO 2 aqueous solution (step S210: hereinafter, also referred to as "separation step"), calcium is precipitated. Step S220 (hereinafter, also referred to as "precipitation step"), and a step of recovering the precipitated solid component (step S230: hereinafter, also referred to as "recovery step"), and the like can be included.
（分離工程：製鋼スラグとＣＯ２水溶液との分離）
本工程では、カルシウムが溶解したＣＯ２水溶液（上澄み液）と、製鋼スラグとを分離する（工程Ｓ２１０）。分離は、公知の方法で行うことができる。分離方法の例には、濾過、およびＣＯ２水溶液を静置して製鋼スラグを沈殿させる方法が含まれる。スラグを沈殿させたときは、さらに上澄み液のみを回収してもよいし、後の工程で析出する固体成分が製鋼スラグと混じらない限りにおいて、上澄み液および沈殿した製鋼スラグを含む２成分系において、上澄み液に対してのみこれ以降の工程を行ってもよい。 (Separation process: Separation of steelmaking slag and CO 2 aqueous solution)
In this step, a CO 2 aqueous solution (supernatant liquid) in which calcium is dissolved is separated from steelmaking slag (step S210). The separation can be carried out by known methods. Examples of separation methods include filtration and methods in which a CO 2 aqueous solution is allowed to settle to precipitate steelmaking slag. When the slag is precipitated, only the supernatant liquid may be further recovered, or in the two-component system including the supernatant liquid and the precipitated steelmaking slag unless the solid component deposited in the later step is mixed with the steelmaking slag. The subsequent steps may be performed only on the supernatant fluid.
本工程では、カルシウムが溶解したＣＯ２水溶液（上澄み液）と、製鋼スラグとを分離する（工程Ｓ２１０）。分離は、公知の方法で行うことができる。分離方法の例には、濾過、およびＣＯ２水溶液を静置して製鋼スラグを沈殿させる方法が含まれる。スラグを沈殿させたときは、さらに上澄み液のみを回収してもよいし、後の工程で析出する固体成分が製鋼スラグと混じらない限りにおいて、上澄み液および沈殿した製鋼スラグを含む２成分系において、上澄み液に対してのみこれ以降の工程を行ってもよい。 (Separation process: Separation of steelmaking slag and CO 2 aqueous solution)
In this step, a CO 2 aqueous solution (supernatant liquid) in which calcium is dissolved is separated from steelmaking slag (step S210). The separation can be carried out by known methods. Examples of separation methods include filtration and methods in which a CO 2 aqueous solution is allowed to settle to precipitate steelmaking slag. When the slag is precipitated, only the supernatant liquid may be further recovered, or in the two-component system including the supernatant liquid and the precipitated steelmaking slag unless the solid component deposited in the later step is mixed with the steelmaking slag. The subsequent steps may be performed only on the supernatant fluid.
（析出工程：カルシウムを含む固体成分の析出）
本工程では、ＣＯ２水溶液に溶出したカルシウムを、カルシウムを含む固体成分として析出させる（工程Ｓ２２０）。ＣＯ２水溶液に溶出したカルシウムは、公知の方法で析出させることができる。ＣＯ２水溶液に溶出したカルシウムを固体成分として析出させる方法の例には、ＣＯ２水溶液から二酸化炭素を除去する方法およびＣＯ２水溶液のｐＨを高くする方法が含まれる。 (Deposition process: precipitation of solid component containing calcium)
In this step, calcium eluted in a CO 2 aqueous solution is precipitated as a solid component containing calcium (step S220). Calcium eluted in a CO 2 aqueous solution can be precipitated by a known method. Examples of the method of precipitating calcium eluted in a CO 2 aqueous solution as a solid component include a method of removing carbon dioxide from a CO 2 aqueous solution and a method of raising the pH of the CO 2 aqueous solution.
本工程では、ＣＯ２水溶液に溶出したカルシウムを、カルシウムを含む固体成分として析出させる（工程Ｓ２２０）。ＣＯ２水溶液に溶出したカルシウムは、公知の方法で析出させることができる。ＣＯ２水溶液に溶出したカルシウムを固体成分として析出させる方法の例には、ＣＯ２水溶液から二酸化炭素を除去する方法およびＣＯ２水溶液のｐＨを高くする方法が含まれる。 (Deposition process: precipitation of solid component containing calcium)
In this step, calcium eluted in a CO 2 aqueous solution is precipitated as a solid component containing calcium (step S220). Calcium eluted in a CO 2 aqueous solution can be precipitated by a known method. Examples of the method of precipitating calcium eluted in a CO 2 aqueous solution as a solid component include a method of removing carbon dioxide from a CO 2 aqueous solution and a method of raising the pH of the CO 2 aqueous solution.
＜二酸化炭素の除去＞
たとえば、分離工程（工程Ｓ２１０）で製鋼スラグと分離したＣＯ２水溶液から二酸化炭素を除去して、カルシウムを溶出させる工程（工程Ｓ１００）でＣＯ２水溶液中に溶出したカルシウムを析出させることができる。このとき析出されるＣａ化合物の例には、炭酸カルシウム、炭酸カルシウム水和物、および水酸化カルシウムが含まれる。 <Removal of carbon dioxide>
For example, carbon dioxide can be removed from the CO 2 aqueous solution separated from the steelmaking slag in the separation step (step S210), and calcium eluted in the CO 2 aqueous solution can be precipitated in the step of eluting calcium (step S100). Examples of the Ca compound precipitated at this time include calcium carbonate, calcium carbonate hydrate and calcium hydroxide.
たとえば、分離工程（工程Ｓ２１０）で製鋼スラグと分離したＣＯ２水溶液から二酸化炭素を除去して、カルシウムを溶出させる工程（工程Ｓ１００）でＣＯ２水溶液中に溶出したカルシウムを析出させることができる。このとき析出されるＣａ化合物の例には、炭酸カルシウム、炭酸カルシウム水和物、および水酸化カルシウムが含まれる。 <Removal of carbon dioxide>
For example, carbon dioxide can be removed from the CO 2 aqueous solution separated from the steelmaking slag in the separation step (step S210), and calcium eluted in the CO 2 aqueous solution can be precipitated in the step of eluting calcium (step S100). Examples of the Ca compound precipitated at this time include calcium carbonate, calcium carbonate hydrate and calcium hydroxide.
ＣＯ２水溶液から二酸化炭素を除去する方法は、特に限定されない。二酸化炭素を除去する方法の例には、（１）ガスの導入、（２）減圧および（３）加熱が含まれる。
The method for removing carbon dioxide from the CO 2 aqueous solution is not particularly limited. Examples of methods of removing carbon dioxide include (1) gas introduction, (2) vacuum and (3) heating.
（１）ガスの導入
ＣＯ２水溶液中の二酸化炭素の平衡圧力よりも低い二酸化炭素分圧を有するガスをカルシウムが溶解したＣＯ２水溶液中に導入することで、溶解している二酸化炭素と導入したガスとを置換または導入したガスのバブル中に二酸化炭素を拡散（移行）させて、二酸化炭素をＣＯ２水溶液から除去することができる。導入するガスは、水と反応するガス（塩素ガス、亜硫酸ガスなど）でもよいが、ＣＯ２水溶液中に導入することによって生成するイオンと水中に溶出したカルシウムとが塩を形成することによる、カルシウムの析出量の減少を抑制する観点からは、水との反応性が低いガスであることが好ましい。ＣＯ２水溶液中に導入するガスは、無機系ガスでもよく、有機系ガスでもよい。これらのうち、外部に漏れても燃焼や爆発の可能性が少ないことから、無機系ガスがより好ましい。水との反応性が低い無機系ガスの例には、空気、窒素、酸素、水素、アルゴンおよびヘリウムならびにこれらの混合ガスが含まれる。混合ガスには、窒素と酸素とをおおよそ４：１の割合で含む、本工程を実施する環境の空気が含まれる。水との反応性が低い有機系ガスの例には、メタン、エタン、エチレン、アセチレン、プロパンおよびフルオロカーボンが含まれる。 (1) By introducing the CO 2 in an aqueous solution of calcium gas is dissolved with a low partial pressure of carbon dioxide than the equilibrium pressure of carbon dioxide introduced CO 2 in an aqueous solution of gas was introduced carbon dioxide dissolved Carbon dioxide can be removed from the aqueous solution of CO 2 by diffusing carbon dioxide into a bubble of a gas that has been replaced or introduced with gas. The gas to be introduced may be a gas that reacts with water (chlorine gas, sulfur dioxide gas, etc.), but the calcium formed by the ions formed by introducing it into the CO 2 aqueous solution and the calcium dissolved in water forms a salt. From the viewpoint of suppressing a decrease in the amount of precipitation, it is preferable that the gas has low reactivity with water. The gas introduced into the CO 2 aqueous solution may be an inorganic gas or an organic gas. Among these, inorganic gases are more preferable because they have less possibility of combustion or explosion even if they leak to the outside. Examples of inorganic gases having low reactivity with water include air, nitrogen, oxygen, hydrogen, argon and helium and mixed gases thereof. The mixed gas includes the air of the environment in which the present process is performed, which contains nitrogen and oxygen in a ratio of approximately 4: 1. Examples of organic gases having low reactivity with water include methane, ethane, ethylene, acetylene, propane and fluorocarbons.
ＣＯ２水溶液中の二酸化炭素の平衡圧力よりも低い二酸化炭素分圧を有するガスをカルシウムが溶解したＣＯ２水溶液中に導入することで、溶解している二酸化炭素と導入したガスとを置換または導入したガスのバブル中に二酸化炭素を拡散（移行）させて、二酸化炭素をＣＯ２水溶液から除去することができる。導入するガスは、水と反応するガス（塩素ガス、亜硫酸ガスなど）でもよいが、ＣＯ２水溶液中に導入することによって生成するイオンと水中に溶出したカルシウムとが塩を形成することによる、カルシウムの析出量の減少を抑制する観点からは、水との反応性が低いガスであることが好ましい。ＣＯ２水溶液中に導入するガスは、無機系ガスでもよく、有機系ガスでもよい。これらのうち、外部に漏れても燃焼や爆発の可能性が少ないことから、無機系ガスがより好ましい。水との反応性が低い無機系ガスの例には、空気、窒素、酸素、水素、アルゴンおよびヘリウムならびにこれらの混合ガスが含まれる。混合ガスには、窒素と酸素とをおおよそ４：１の割合で含む、本工程を実施する環境の空気が含まれる。水との反応性が低い有機系ガスの例には、メタン、エタン、エチレン、アセチレン、プロパンおよびフルオロカーボンが含まれる。 (1) By introducing the CO 2 in an aqueous solution of calcium gas is dissolved with a low partial pressure of carbon dioxide than the equilibrium pressure of carbon dioxide introduced CO 2 in an aqueous solution of gas was introduced carbon dioxide dissolved Carbon dioxide can be removed from the aqueous solution of CO 2 by diffusing carbon dioxide into a bubble of a gas that has been replaced or introduced with gas. The gas to be introduced may be a gas that reacts with water (chlorine gas, sulfur dioxide gas, etc.), but the calcium formed by the ions formed by introducing it into the CO 2 aqueous solution and the calcium dissolved in water forms a salt. From the viewpoint of suppressing a decrease in the amount of precipitation, it is preferable that the gas has low reactivity with water. The gas introduced into the CO 2 aqueous solution may be an inorganic gas or an organic gas. Among these, inorganic gases are more preferable because they have less possibility of combustion or explosion even if they leak to the outside. Examples of inorganic gases having low reactivity with water include air, nitrogen, oxygen, hydrogen, argon and helium and mixed gases thereof. The mixed gas includes the air of the environment in which the present process is performed, which contains nitrogen and oxygen in a ratio of approximately 4: 1. Examples of organic gases having low reactivity with water include methane, ethane, ethylene, acetylene, propane and fluorocarbons.
（２）減圧
１気圧（約１００ｋＰａ）付近およびそれ以下の圧力環境下では、ＣＯ２水溶液にかかる圧力が低くなると、二酸化炭素の溶解度が減少する。そのため、ＣＯ２水溶液を減圧環境下に置くことで、二酸化炭素をＣＯ２水溶液から除去することができる。たとえば、ＣＯ２水溶液を密閉容器に入れて、ポンプなどによって容器内の空気を排出（脱気）して、容器内を減圧雰囲気にすることによって、二酸化炭素を除去することができる。二酸化炭素の除去量をより多くする観点からは、減圧に加えて、ＣＯ２水溶液への超音波の印加、またはＣＯ２水溶液の撹拌を同時に行ってもよい。 (2) Decompression Under a pressure environment near 1 atmospheric pressure (about 100 kPa) and lower pressure, the solubility of carbon dioxide decreases as the pressure applied to the CO 2 aqueous solution decreases. Therefore, carbon dioxide can be removed from the CO 2 aqueous solution by placing the CO 2 aqueous solution under a reduced pressure environment. For example, putting a CO 2 aqueous solution in a sealed container, such as by discharging the air in the container pump (degassed) to, by the pressure in the container was reduced atmosphere, it is possible to remove carbon dioxide. From the viewpoint of increasing the amount of carbon dioxide removed, the application of ultrasonic waves to the aqueous CO 2 solution or the stirring of the aqueous CO 2 solution may be simultaneously performed in addition to the reduced pressure.
１気圧（約１００ｋＰａ）付近およびそれ以下の圧力環境下では、ＣＯ２水溶液にかかる圧力が低くなると、二酸化炭素の溶解度が減少する。そのため、ＣＯ２水溶液を減圧環境下に置くことで、二酸化炭素をＣＯ２水溶液から除去することができる。たとえば、ＣＯ２水溶液を密閉容器に入れて、ポンプなどによって容器内の空気を排出（脱気）して、容器内を減圧雰囲気にすることによって、二酸化炭素を除去することができる。二酸化炭素の除去量をより多くする観点からは、減圧に加えて、ＣＯ２水溶液への超音波の印加、またはＣＯ２水溶液の撹拌を同時に行ってもよい。 (2) Decompression Under a pressure environment near 1 atmospheric pressure (about 100 kPa) and lower pressure, the solubility of carbon dioxide decreases as the pressure applied to the CO 2 aqueous solution decreases. Therefore, carbon dioxide can be removed from the CO 2 aqueous solution by placing the CO 2 aqueous solution under a reduced pressure environment. For example, putting a CO 2 aqueous solution in a sealed container, such as by discharging the air in the container pump (degassed) to, by the pressure in the container was reduced atmosphere, it is possible to remove carbon dioxide. From the viewpoint of increasing the amount of carbon dioxide removed, the application of ultrasonic waves to the aqueous CO 2 solution or the stirring of the aqueous CO 2 solution may be simultaneously performed in addition to the reduced pressure.
（３）加熱
１気圧（約１００ｋＰａ）付近およびそれ以下の圧力環境下では、ＣＯ２水溶液の温度が高くなると、二酸化炭素の溶解度が減少する。そのため、ＣＯ２水溶液を加熱することによって、二酸化炭素をＣＯ２水溶液から除去することができる。このとき、加熱コストを低くする観点から、水の蒸気圧が雰囲気圧力を超えない範囲内の温度に加熱することが好ましい。たとえば、雰囲気圧力が１気圧であるときは、加熱温度は、１００℃未満であることが好ましい。ＣＯ２水溶液を加熱すると、二酸化炭素が除去されるだけでなく、Ｃａ化合物（炭酸カルシウム）の溶解度が低下するため、カルシウムがより析出しやすくなる。 (3) Heating Under a pressure environment near 1 atmospheric pressure (about 100 kPa) and lower pressure, the solubility of carbon dioxide decreases as the temperature of the aqueous solution of CO 2 increases. Therefore, by heating the CO 2 solution, it is possible to remove carbon dioxide from the CO 2 solution. At this time, from the viewpoint of lowering the heating cost, it is preferable to heat to a temperature within the range where the vapor pressure of water does not exceed the atmospheric pressure. For example, when the atmospheric pressure is 1 atm, the heating temperature is preferably less than 100.degree. When the CO 2 aqueous solution is heated, not only carbon dioxide is removed but also the solubility of the Ca compound (calcium carbonate) is reduced, so that calcium is more easily precipitated.
１気圧（約１００ｋＰａ）付近およびそれ以下の圧力環境下では、ＣＯ２水溶液の温度が高くなると、二酸化炭素の溶解度が減少する。そのため、ＣＯ２水溶液を加熱することによって、二酸化炭素をＣＯ２水溶液から除去することができる。このとき、加熱コストを低くする観点から、水の蒸気圧が雰囲気圧力を超えない範囲内の温度に加熱することが好ましい。たとえば、雰囲気圧力が１気圧であるときは、加熱温度は、１００℃未満であることが好ましい。ＣＯ２水溶液を加熱すると、二酸化炭素が除去されるだけでなく、Ｃａ化合物（炭酸カルシウム）の溶解度が低下するため、カルシウムがより析出しやすくなる。 (3) Heating Under a pressure environment near 1 atmospheric pressure (about 100 kPa) and lower pressure, the solubility of carbon dioxide decreases as the temperature of the aqueous solution of CO 2 increases. Therefore, by heating the CO 2 solution, it is possible to remove carbon dioxide from the CO 2 solution. At this time, from the viewpoint of lowering the heating cost, it is preferable to heat to a temperature within the range where the vapor pressure of water does not exceed the atmospheric pressure. For example, when the atmospheric pressure is 1 atm, the heating temperature is preferably less than 100.degree. When the CO 2 aqueous solution is heated, not only carbon dioxide is removed but also the solubility of the Ca compound (calcium carbonate) is reduced, so that calcium is more easily precipitated.
二酸化炭素の除去量をより多くする観点からは、上記（１）～（３）を組み合わせて行ってもよい。なお、これらの組合せは、ガスや熱の供給体制、立地、工場内副生ガスの利用などを考慮して、最適な組合せを選べばよい。
From the viewpoint of increasing the removal amount of carbon dioxide, the above (1) to (3) may be combined. In addition, what is necessary is just to select the optimal combination in consideration of the supply system of gas or heat, a location, utilization of by-product gas in a factory, etc. of these combinations.
たとえば、ガスをＣＯ２水溶液中に導入しながら、ガスの導入量以上に排気して、減圧雰囲気することによって、ガスの導入による二酸化炭素の除去の効果と撹拌効果、およびＣＯ２水溶液の減圧による二酸化炭素の除去の効果が得られ、二酸化炭素を効率的に除去できる。このとき、さらに加熱することによって、二酸化炭素の除去の効果がさらに促進される。また、このとき、ガスのＣＯ２水溶液中への導入の効果とＣＯ２水溶液の減圧との相加効果によって、二酸化炭素を容易に除去することができるため、加熱温度を高くする必要がなく、加熱コストを削減できる。
For example, by introducing the gas into the aqueous solution of CO 2 , exhausting the gas above the introduction amount, and setting the reduced pressure atmosphere, the effect and removal effect of carbon dioxide removal by the introduction of the gas, and the reduced pressure of the aqueous solution of CO 2 The effect of removing carbon dioxide can be obtained, and carbon dioxide can be removed efficiently. At this time, further heating further promotes the effect of removing carbon dioxide. At this time, the additive effect of the decompression effect as CO 2 aqueous solution introduced into the CO 2 aqueous solution of the gas, for the carbon dioxide can be easily removed, it is not necessary to raise the heating temperature, The heating cost can be reduced.
＜ｐＨの上昇＞
製鋼スラグと分離したＣＯ２水溶液のｐＨを上げることで、カルシウムを含む固体成分をＣＯ２水溶液中に析出させることができる。二酸化炭素の水溶液中での存在状態は、（式３）～（式５）で表される。ｐＨ８．５程度までは（式３）～（式４）の平衡関係にあり、ｐＨ８．５以上では（式４）～（式５）の平衡関係にある。各イオンと物質の存在比率を図１０に示す。ここで［Ｈ２ＣＯ３ ＊］は［ＣＯ２］と［Ｈ２ＣＯ３］を合わせた濃度である。これらより、ｐＨを上げると、ｐＨ８．５程度までは（式６）に示すようにカルシウムイオン（Ｃａ２＋）と炭酸水素イオン（ＨＣＯ３ －）と結合して難溶性の炭酸カルシウム（ＣａＣＯ３）となることによって、カルシウムが析出すると考えられる。ｐＨ８．５以上では（式７）に示すようにカルシウムイオンと炭酸イオンとの結合反応により難溶性の炭酸カルシウム（ＣａＣＯ３）となることによって、カルシウムが析出すると考えられる。なお、これらの二酸化炭素の存在状態とｐＨの関係を示す図１０は公知の文献（例えば、「腐食・防食ハンドブック」社団法人腐食・防食協会、２０００年、ｐ．１５５）に記載されている。
ＣＯ２ ＋ Ｈ２Ｏ ⇔ Ｈ２ＣＯ３ （式３）
Ｈ２ＣＯ３ ⇔ Ｈ＋ ＋ ＨＣＯ３ － （式４）
ＨＣＯ３ － ⇔ Ｈ＋ ＋ ＣＯ３ ２－ （式５）
Ｃａ２＋ ＋ ＨＣＯ３ － ⇔ Ｈ＋ ＋ ＣａＣＯ３ （式６）
Ｃａ２＋ ＋ ＣＯ３ ２－ ⇔ ＣａＣＯ３ （式７） <The rise of pH>
By raising the pH of the CO 2 aqueous solution separated from the steelmaking slag, the calcium-containing solid component can be precipitated in the CO 2 aqueous solution. The state of carbon dioxide in an aqueous solution is represented by (Expression 3) to (Expression 5). There is an equilibrium relationship of (equation 3) to (equation 4) up to about pH 8.5, and an equilibrium relationship of (equation 4) to (equation 5) above pH 8.5. The abundance ratio of each ion to the substance is shown in FIG. Here, [H 2 CO 3 * ] is the combined concentration of [CO 2 ] and [H 2 CO 3 ]. From these, raising the pH, up to about pH8.5 calcium as shown in (Equation 6) ions (Ca 2+) and bicarbonate ion (HCO 3 -) and bound to insoluble of calcium carbonate (CaCO 3) It is thought that calcium precipitates by becoming. At a pH of 8.5 or more, as shown in (Equation 7), it is considered that calcium is precipitated by becoming a poorly soluble calcium carbonate (CaCO 3 ) by the binding reaction between calcium ions and carbonate ions. In addition, FIG. 10 showing the relationship between the presence state of carbon dioxide and the pH is described in a known document (for example, "Corrosion and Corrosion Prevention Handbook" Association for Corrosion and Corrosion Protection, 2000, p. 155).
CO 2 + H 2 O ⇔ H 2 CO 3 (Equation 3)
H 2 CO 3 ⇔ H + + HCO 3 - ( Equation 4)
HCO 3 - ⇔ H + + CO 3 2- (Equation 5)
Ca 2+ + HCO 3 - ⇔ H + + CaCO 3 (Equation 6)
Ca 2+ + CO 3 2- ⇔ CaCO 3 (Equation 7)
製鋼スラグと分離したＣＯ２水溶液のｐＨを上げることで、カルシウムを含む固体成分をＣＯ２水溶液中に析出させることができる。二酸化炭素の水溶液中での存在状態は、（式３）～（式５）で表される。ｐＨ８．５程度までは（式３）～（式４）の平衡関係にあり、ｐＨ８．５以上では（式４）～（式５）の平衡関係にある。各イオンと物質の存在比率を図１０に示す。ここで［Ｈ２ＣＯ３ ＊］は［ＣＯ２］と［Ｈ２ＣＯ３］を合わせた濃度である。これらより、ｐＨを上げると、ｐＨ８．５程度までは（式６）に示すようにカルシウムイオン（Ｃａ２＋）と炭酸水素イオン（ＨＣＯ３ －）と結合して難溶性の炭酸カルシウム（ＣａＣＯ３）となることによって、カルシウムが析出すると考えられる。ｐＨ８．５以上では（式７）に示すようにカルシウムイオンと炭酸イオンとの結合反応により難溶性の炭酸カルシウム（ＣａＣＯ３）となることによって、カルシウムが析出すると考えられる。なお、これらの二酸化炭素の存在状態とｐＨの関係を示す図１０は公知の文献（例えば、「腐食・防食ハンドブック」社団法人腐食・防食協会、２０００年、ｐ．１５５）に記載されている。
ＣＯ２ ＋ Ｈ２Ｏ ⇔ Ｈ２ＣＯ３ （式３）
Ｈ２ＣＯ３ ⇔ Ｈ＋ ＋ ＨＣＯ３ － （式４）
ＨＣＯ３ － ⇔ Ｈ＋ ＋ ＣＯ３ ２－ （式５）
Ｃａ２＋ ＋ ＨＣＯ３ － ⇔ Ｈ＋ ＋ ＣａＣＯ３ （式６）
Ｃａ２＋ ＋ ＣＯ３ ２－ ⇔ ＣａＣＯ３ （式７） <The rise of pH>
By raising the pH of the CO 2 aqueous solution separated from the steelmaking slag, the calcium-containing solid component can be precipitated in the CO 2 aqueous solution. The state of carbon dioxide in an aqueous solution is represented by (Expression 3) to (Expression 5). There is an equilibrium relationship of (equation 3) to (equation 4) up to about pH 8.5, and an equilibrium relationship of (equation 4) to (equation 5) above pH 8.5. The abundance ratio of each ion to the substance is shown in FIG. Here, [H 2 CO 3 * ] is the combined concentration of [CO 2 ] and [H 2 CO 3 ]. From these, raising the pH, up to about pH8.5 calcium as shown in (Equation 6) ions (Ca 2+) and bicarbonate ion (HCO 3 -) and bound to insoluble of calcium carbonate (CaCO 3) It is thought that calcium precipitates by becoming. At a pH of 8.5 or more, as shown in (Equation 7), it is considered that calcium is precipitated by becoming a poorly soluble calcium carbonate (CaCO 3 ) by the binding reaction between calcium ions and carbonate ions. In addition, FIG. 10 showing the relationship between the presence state of carbon dioxide and the pH is described in a known document (for example, "Corrosion and Corrosion Prevention Handbook" Association for Corrosion and Corrosion Protection, 2000, p. 155).
CO 2 + H 2 O ⇔ H 2 CO 3 (Equation 3)
H 2 CO 3 ⇔ H + + HCO 3 - ( Equation 4)
HCO 3 - ⇔ H + + CO 3 2- (Equation 5)
Ca 2+ + HCO 3 - ⇔ H + + CaCO 3 (Equation 6)
Ca 2+ + CO 3 2- ⇔ CaCO 3 (Equation 7)
二酸化炭素を含む水溶液に製鋼スラグを接触させてカルシウムを溶出させ、固液分離して得た水溶液のｐＨを上げた場合、ｐＨ８．５までにほとんどのＣａが析出するため、カルシウムイオンと炭酸水素イオンと反応が支配的である。
When the steelmaking slag is brought into contact with an aqueous solution containing carbon dioxide to elute calcium and the pH of the aqueous solution obtained by solid-liquid separation is raised, most of the Ca precipitates by pH 8.5, so calcium ions and hydrogen carbonate Ions and reactions dominate.
カルシウムが析出しはじめると、炭酸カルシウムによる白濁がＣＯ２水溶液中に生じる。ＣＯ２水溶液のｐＨは、目視でこの白濁が確認できる程度に上げれば十分である。カルシウムをより十分に析出させて、カルシウムの回収率をより高める観点からは、分離工程（工程Ｓ２１０）において製鋼スラグと分離したＣＯ２水溶液のｐＨに対して、ｐＨを０．２以上上げることが好ましく、０．３以上上げることがより好ましく、１．０以上上げることがさらに好ましく、１．５以上上げることがさらに好ましく、２．０以上上げることがさらに好ましい。
When calcium starts to precipitate, turbidity due to calcium carbonate is generated in the aqueous solution of CO 2 . It is sufficient if the pH of the aqueous solution of CO 2 is raised to such an extent that this cloudiness can be confirmed visually. From the viewpoint of more fully depositing calcium and increasing the recovery rate of calcium, raising the pH by 0.2 or more with respect to the pH of the CO 2 aqueous solution separated from the steelmaking slag in the separation step (step S210) Preferably, it is more preferably 0.3 or more, more preferably 1.0 or more, still more preferably 1.5 or more, and even more preferably 2.0 or more.
このとき、ＣＯ２水溶液のｐＨを測定しながら行うことが好ましい。ＣＯ２水溶液のｐＨは、公知のガラス電極法で測定することができる。
At this time, it is preferable to carry out while measuring the pH of the CO 2 aqueous solution. The pH of the CO 2 aqueous solution can be measured by a known glass electrode method.
本工程ではカルシウムのみならずリンなどの他の元素も含む固体成分が析出するが、本発明者の知見によれば、ｐＨを上昇させ始めた直後に析出する固体成分（以下、単に「初期析出物」ともいう。）はリンを含む化合物（以下、単に「リン化合物」ともいう。）の含有比がより高く、遅れて析出する固体成分（以下、単に「後期析出物」ともいう。）はリンの含有比がより低い。そのため、ｐＨを上昇させる途中で後述する回収する工程（工程Ｓ２３０）を行い、初期析出物を回収することで、リンの比率がより高い固体成分とリンの比率がより低い固体成分とを分離して回収することができる。
Although solid components containing not only calcium but also other elements such as phosphorus are precipitated in this step, according to the present inventor's knowledge, solid components which precipitate immediately after starting to raise the pH (hereinafter referred to simply as “initial precipitation The content of the phosphorus-containing compound (hereinafter, also simply referred to as "phosphorus compound") is higher, and the later precipitated solid component (hereinafter, also simply referred to as "late precipitate") has a higher content ratio. Lower phosphorus content ratio. Therefore, the step of recovering (step S230) to be described later is performed while raising the pH, and the initial precipitate is recovered to separate the solid component having a higher ratio of phosphorus and the solid component having a lower ratio of phosphorus. Can be collected.
製鋼スラグから回収したリン化合物は、リン資源として再利用できる。よって、リン化合物の含有量が多い固体成分を回収すると、リンの再利用が容易となる。また、製鋼スラグから回収したＣａ化合物は、製鉄原料として再利用できるが、この製鉄原料がリン化合物を含んでいると、鉄が脆くなる。よって、製鉄原料として再利用する固体成分には、リン化合物の含有量が少ないほうがよい。したがって、リンおよびカルシウムを含むＣＯ２水溶液から、リン化合物の含有量が多い固体成分と、リン化合物の含有量が少ない固体成分とを別個に得ると、回収した固体成分の精製が容易または不要になり、かつ、回収した固体成分を用いた製品の品質をより向上させることができる。
Phosphorus compounds recovered from steelmaking slag can be reused as phosphorus resources. Therefore, when the solid component having a high content of phosphorus compound is recovered, reuse of phosphorus is facilitated. Moreover, although Ca compound collect | recovered from steelmaking slag can be recycled as a steelmaking raw material, if this ironmaking raw material contains a phosphorus compound, iron will become brittle. Therefore, it is better for the solid component to be recycled as the iron making material to have a low content of the phosphorus compound. Therefore, if a solid component with a high content of phosphorus compound and a solid component with a low content of phosphorus compound are separately obtained from an aqueous solution of CO 2 containing phosphorus and calcium, purification of the recovered solid component becomes easy or unnecessary. And the quality of the product using the recovered solid component can be further improved.
このとき、リンは、ＣＯ２水溶液のｐＨが１．０上がるまでにその大部分が析出する。そのため、初期析出物中のリンの含有比をより高め、かつ、後期析出物中のカルシウムの含有比をより高める観点からは、初期析出物は、ｐＨが１．０上がる以前に回収することが好ましく、０．６上がる以前に回収することがより好ましく、０．４上がる以前に回収することがさらに好ましい。
At this time, most of phosphorus is deposited until the pH of the aqueous solution of CO 2 rises by 1.0. Therefore, from the viewpoint of further increasing the content ratio of phosphorus in the initial precipitate and further increasing the content ratio of calcium in the late precipitate, the initial precipitate may be recovered before the pH rises by 1.0. Preferably, it is more preferable to recover before rising by 0.6, and more preferable to recover before rising by 0.4.
ＣＯ２水溶液のｐＨは、たとえば、ＣＯ２水溶液にアルカリ性物質を投入することで、上げることができる。ＣＯ２水溶液に投入することができるアルカリ性物質の例には、水酸化カルシウム、アンモニアおよび水酸化ナトリウムが含まれる。水酸化カルシウム、アンモニアまたは水酸化ナトリウムを投入するときは、これらの物質を水に溶解させた溶液を、前記ＣＯ２水溶液に添加するとよい。水酸化カルシウム、アンモニアおよび水酸化ナトリウムは市販のものでもよいし、廃液その他の液体中に含まれるものでもよい。廃液中の水酸化カルシウムを投入する場合、たとえば、炭化カルシウム（カルシウムカーバイド）と水とを反応させてアセチレンを製造する際に生じる廃液をＣＯ２水溶液に添加することができる。また、製鋼スラグを水に浸漬して用意したスラグ浸出水、上述した磁選水または上述した水和処理水を前記ＣＯ２水溶液に投入してもよい。スラグ浸出水、磁選水および水和処理水は、カルシウムを回収しようとしている製鋼スラグについての水への浸漬、磁選または水和処理によって得たものであってもよいし、別の製鋼スラグの水への浸漬、磁選または水和処理によって得たものであってもよい。アルカリ性物質の中では、水酸化カルシウム、水酸化カルシウム主体の廃液、スラグ浸出水、磁選水、水和処理水を使うのがよい。これらは含まれているもののほとんどが水酸化カルシウムであるため、これらを使うことによって、得られるカルシウム化合物にアンモニアやナトリウムなどの不要な物質の混入量が低減される。また、水に残るアンモニアまたは水酸化ナトリウムを使う場合とは異なり、カルシウム化合物の回収後に残った水の再処理が不要になる。
PH of CO 2 aqueous solution, for example, by introducing an alkaline substance into CO 2 aqueous solution, can be increased. Examples of alkaline substances that can be introduced into the aqueous CO 2 solution include calcium hydroxide, ammonia and sodium hydroxide. When calcium hydroxide, ammonia or sodium hydroxide is introduced, a solution of these substances in water may be added to the aqueous CO 2 solution. Calcium hydroxide, ammonia and sodium hydroxide may be commercially available, or may be contained in waste liquid or other liquid. When calcium hydroxide in waste liquid is charged, for example, the waste liquid produced in the reaction of calcium carbide (calcium carbide) with water to produce acetylene can be added to the aqueous CO 2 solution. In addition, slag leaching water prepared by immersing steelmaking slag in water, the above-mentioned magnetic separated water or the above-mentioned hydration treated water may be introduced into the above-mentioned CO 2 aqueous solution. Slag leachate, magnetic separation water and hydration treated water may be obtained by immersion in water, magnetic separation or hydration treatment of steelmaking slag from which calcium is to be recovered, or water of another steelmaking slag. It may be obtained by immersion, magnetic separation or hydration treatment. Among alkaline substances, it is preferable to use calcium hydroxide, calcium hydroxide-based waste solution, slag leachate, magnetic separation water, hydration treated water. Since most of those contained are calcium hydroxide, their use reduces the amount of contamination of unnecessary substances such as ammonia and sodium in the obtained calcium compound. In addition, unlike the case of using ammonia or sodium hydroxide remaining in water, it is not necessary to reprocess the water remaining after recovery of the calcium compound.
ＣＯ２水溶液のｐＨを上げると、ＣＯ２水溶液に含まれる少量のＦｅ、ＭｎおよびＰなども前記固体成分として析出する。そのため、本実施形態に係る方法によってカルシウムを回収した後のＣＯ２水溶液は、排水処理を簡素化するかまたは不要にして、排水処理のコストを抑制することができる。
When the pH of the aqueous solution of CO 2 is increased, small amounts of Fe, Mn, P and the like contained in the aqueous solution of CO 2 are also precipitated as the solid component. Therefore, the CO 2 aqueous solution after calcium recovery by the method according to the present embodiment can simplify or eliminate the waste water treatment, thereby suppressing the cost of the waste water treatment.
カルシウムを回収した後のＣＯ２水溶液は、Ｃａ、Ｆｅ、Ｍｎ、Ａｌ、Ｐなどの金属元素およびＣＯ２をほとんど含んでいないので、工程内で再利用が可能であり、排水レス化を可能とし得る。
Since the aqueous solution of CO 2 after recovery of calcium contains almost no metal element such as Ca, Fe, Mn, Al, P and CO 2 , it can be reused in the process, enabling waste water elimination obtain.
カルシウムの回収率をより高める観点からは、二酸化炭素の除去とｐＨの上昇とを組みあわせて行ってもよい。
From the viewpoint of further increasing the calcium recovery rate, the removal of carbon dioxide and the increase in pH may be performed in combination.
（回収工程：固体成分の回収）
本工程では、析出工程（工程Ｓ２２０）で析出した固体成分を回収する（工程Ｓ２３０）。析出した固体成分は、減圧濾過および加圧濾過を含む公知の方法によって回収することができる。この固体成分には、製鋼スラグ由来のカルシウムが含まれる。 (Recovery process: recovery of solid components)
In this step, the solid component precipitated in the precipitation step (step S220) is recovered (step S230). The precipitated solid component can be recovered by known methods including vacuum filtration and pressure filtration. This solid component includes calcium derived from steelmaking slag.
本工程では、析出工程（工程Ｓ２２０）で析出した固体成分を回収する（工程Ｓ２３０）。析出した固体成分は、減圧濾過および加圧濾過を含む公知の方法によって回収することができる。この固体成分には、製鋼スラグ由来のカルシウムが含まれる。 (Recovery process: recovery of solid components)
In this step, the solid component precipitated in the precipitation step (step S220) is recovered (step S230). The precipitated solid component can be recovered by known methods including vacuum filtration and pressure filtration. This solid component includes calcium derived from steelmaking slag.
以下、本発明について実施例を参照してより具体的に説明する。なお、これらの実施例は、本発明の範囲を以下に記載の具体的方法に限定するものではない。
Hereinafter, the present invention will be more specifically described with reference to examples. Note that these examples do not limit the scope of the present invention to the specific methods described below.
［実験１］
表１に記載の成分比率を有する製鋼スラグを準備した。なお、製鋼スラグの成分は、化学分析法によって測定した。製鋼スラグは、予備破砕した後、目開き１０６μｍの篩を通過させたものを使用した。 [Experiment 1]
The steelmaking slag which has a component ratio of Table 1 was prepared. In addition, the component of steelmaking slag was measured by the chemical analysis method. The steelmaking slag was pre-crushed and then passed through a sieve with an opening of 106 μm.
表１に記載の成分比率を有する製鋼スラグを準備した。なお、製鋼スラグの成分は、化学分析法によって測定した。製鋼スラグは、予備破砕した後、目開き１０６μｍの篩を通過させたものを使用した。 [Experiment 1]
The steelmaking slag which has a component ratio of Table 1 was prepared. In addition, the component of steelmaking slag was measured by the chemical analysis method. The steelmaking slag was pre-crushed and then passed through a sieve with an opening of 106 μm.
表１に示す製鋼スラグの一部を、以下の方法（水和処理－１）で水和処理した。その後、水和処理していない製鋼スラグおよび上記水和処理した製鋼スラグのいずれかを、以下の方法（Ｃａ溶出－１～Ｃａ溶出－３のいずれか）でＣＯ２水溶液と接触させた。その後、ＣＯ２水溶液へのカルシウムの溶出率を測定した。
A part of the steelmaking slag shown in Table 1 was subjected to hydration treatment by the following method (hydration treatment-1). Thereafter, either the non-hydrated steelmaking slag or the above-mentioned hydrated steelmaking slag was brought into contact with the aqueous CO 2 solution by the following method (any of Ca elution-1 to Ca elution-3). Then, the elution rate of calcium to the CO 2 aqueous solution was measured.
（水和処理－１：撹拌による水和）
撹拌インペラを有する内径３５０ｍｍの円筒状の容器に１０Ｌの水および０．１５～０．３ｋｇの上記製鋼スラグを投入し、撹拌インペラを３００ｒｐｍで１時間回転させた。 (Hydration treatment 1: hydration by stirring)
10 L of water and 0.15 to 0.3 kg of the above steelmaking slag were charged into a cylindrical vessel with an inner diameter of 350 mm having a stirring impeller, and the stirring impeller was rotated at 300 rpm for 1 hour.
撹拌インペラを有する内径３５０ｍｍの円筒状の容器に１０Ｌの水および０．１５～０．３ｋｇの上記製鋼スラグを投入し、撹拌インペラを３００ｒｐｍで１時間回転させた。 (Hydration treatment 1: hydration by stirring)
10 L of water and 0.15 to 0.3 kg of the above steelmaking slag were charged into a cylindrical vessel with an inner diameter of 350 mm having a stirring impeller, and the stirring impeller was rotated at 300 rpm for 1 hour.
（Ｃａ溶出－１：ボールによる底部側での粉砕等）
図１に示す構成を有する、粉砕媒体および撹拌スクリューを内部に有する内径３５０ｍｍの円筒状の粉砕・沈降槽を用意した。 (Ca elution 1: Crushing on the bottom side with balls, etc.)
A cylindrical grinding / settling tank having an inner diameter of 350 mm, having a grinding medium and a stirring screw inside, having the configuration shown in FIG. 1 was prepared.
図１に示す構成を有する、粉砕媒体および撹拌スクリューを内部に有する内径３５０ｍｍの円筒状の粉砕・沈降槽を用意した。 (Ca elution 1: Crushing on the bottom side with balls, etc.)
A cylindrical grinding / settling tank having an inner diameter of 350 mm, having a grinding medium and a stirring screw inside, having the configuration shown in FIG. 1 was prepared.
この粉砕・沈降槽に、表２に示す量の、水和処理していない製鋼スラグおよび上記水和処理した製鋼スラグのいずれかを投入し、合計水量が３０Ｌとなるように水を加えた。そこに嵩体積（見かけ体積）が３．７Ｌとなる量のボール（粉砕媒体）を投入した。ボールの直径は１０ｍｍだった。その後、撹拌インペラを７０ｒｐｍで回転させてボールを撹拌し、ボールと製鋼スラグとを接触させて製鋼スラグを粉砕等した。同時に、９Ｌ／ｍｉｎの量の二酸化炭素を、製鋼スラグが水に懸濁したスラリーの中に二酸化炭素導入部の導入口から導入した。
In this crushing and settling tank, either the non-hydrated steelmaking slag or the hydrated steelmaking slag in the amount shown in Table 2 was charged, and water was added so that the total amount of water was 30L. The ball (grind medium) of the quantity from which bulk volume (apparent volume) will be 3.7 L was thrown there. The diameter of the ball was 10 mm. After that, the stirring impeller was rotated at 70 rpm to stir the balls, and the balls and the steelmaking slag were brought into contact to grind the steelmaking slag and the like. At the same time, carbon dioxide in an amount of 9 L / min was introduced into the slurry in which steelmaking slag was suspended in water from the inlet of the carbon dioxide inlet.
（Ｃａ溶出－２：撹拌）
ボール（粉砕媒体）を投入しなかった以外は上記Ｃａ溶出－１と同様の構成とした粉砕・沈降槽に、表２に示す量の、水和処理していない製鋼スラグおよび上記水和処理した製鋼スラグのいずれかを投入し、合計水量が３０Ｌとなるように水を加えた後、製鋼スラグが沈降しないように撹拌インペラを３００ｒｐｍで回転させた。撹拌インペラは、回転により製鋼スラグに接触したが、製鋼スラグを粉砕等はしなかった。同時に、９Ｌ／ｍｉｎの量の二酸化炭素を、製鋼スラグが水に懸濁したスラリーの中に二酸化炭素導入部から導入した。 (Ca elution-2: stirring)
A non-hydrated steelmaking slag and the above-mentioned hydration treatment were added to the grinding / settling tank having the same constitution as the above Ca elution-1 except that the ball (grind medium) was not added. After introducing any of the steelmaking slag and adding water so that the total amount of water is 30 L, the stirring impeller was rotated at 300 rpm so that the steelmaking slag did not settle. The stirring impeller was in contact with the steelmaking slag by rotation, but the steelmaking slag was not crushed or the like. At the same time, carbon dioxide in an amount of 9 L / min was introduced from the carbon dioxide introduction portion into the slurry in which steelmaking slag was suspended in water.
ボール（粉砕媒体）を投入しなかった以外は上記Ｃａ溶出－１と同様の構成とした粉砕・沈降槽に、表２に示す量の、水和処理していない製鋼スラグおよび上記水和処理した製鋼スラグのいずれかを投入し、合計水量が３０Ｌとなるように水を加えた後、製鋼スラグが沈降しないように撹拌インペラを３００ｒｐｍで回転させた。撹拌インペラは、回転により製鋼スラグに接触したが、製鋼スラグを粉砕等はしなかった。同時に、９Ｌ／ｍｉｎの量の二酸化炭素を、製鋼スラグが水に懸濁したスラリーの中に二酸化炭素導入部から導入した。 (Ca elution-2: stirring)
A non-hydrated steelmaking slag and the above-mentioned hydration treatment were added to the grinding / settling tank having the same constitution as the above Ca elution-1 except that the ball (grind medium) was not added. After introducing any of the steelmaking slag and adding water so that the total amount of water is 30 L, the stirring impeller was rotated at 300 rpm so that the steelmaking slag did not settle. The stirring impeller was in contact with the steelmaking slag by rotation, but the steelmaking slag was not crushed or the like. At the same time, carbon dioxide in an amount of 9 L / min was introduced from the carbon dioxide introduction portion into the slurry in which steelmaking slag was suspended in water.
（Ｃａ溶出－３：ボールミルによる容器全体での粉砕等１）
内径３７０ｍｍのボールミルに、嵩体積（見かけ体積）が３．７Ｌとなる量のボール（粉砕媒体）を投入した。ボールの直径は１０ｍｍだった。 (Ca leaching -3: Grinding of the whole container by ball mill etc. 1)
A ball (grind medium) of an amount such that the bulk volume (apparent volume) was 3.7 L was charged into a ball mill having an inner diameter of 370 mm. The diameter of the ball was 10 mm.
内径３７０ｍｍのボールミルに、嵩体積（見かけ体積）が３．７Ｌとなる量のボール（粉砕媒体）を投入した。ボールの直径は１０ｍｍだった。 (Ca leaching -3: Grinding of the whole container by ball mill etc. 1)
A ball (grind medium) of an amount such that the bulk volume (apparent volume) was 3.7 L was charged into a ball mill having an inner diameter of 370 mm. The diameter of the ball was 10 mm.
このボールミルに、表２に示す量の、水和処理していない製鋼スラグおよび上記水和処理した製鋼スラグのいずれかを投入し、合計水量が３０Ｌとなるように水を加えた後、ボールミルを７０ｒｐｍで回転させ、回転するボールと製鋼スラグとを接触させて製鋼スラグを粉砕等した。同時に、９Ｌ／ｍｉｎの量の二酸化炭素を、製鋼スラグが水に懸濁したスラリーの中に導入した。
Into this ball mill, any of the non-hydrated steelmaking slag and the above-mentioned hydrated steelmaking slag in the amounts shown in Table 2 is added, water is added so that the total amount of water is 30 L, and then the ball mill is The steelmaking slag was crushed by rotating the ball at 70 rpm and bringing the rotating ball into contact with the steelmaking slag. At the same time, carbon dioxide in an amount of 9 L / min was introduced into the slurry in which steelmaking slag was suspended in water.
（Ｃａ溶出－４：ボールミルによる容器全体での粉砕等２）
内径２１０ｍｍのボールミルに嵩体積（見かけ体積）が１．３Ｌとなる量のボール（粉砕媒体）を投入した。ボールの直径は１０ｍｍだった。 (Ca leaching -4: Grinding of the whole container by ball mill etc. 2)
A ball (grind medium) of an amount such that the bulk volume (apparent volume) was 1.3 L was introduced into a ball mill having an inner diameter of 210 mm. The diameter of the ball was 10 mm.
内径２１０ｍｍのボールミルに嵩体積（見かけ体積）が１．３Ｌとなる量のボール（粉砕媒体）を投入した。ボールの直径は１０ｍｍだった。 (Ca leaching -4: Grinding of the whole container by ball mill etc. 2)
A ball (grind medium) of an amount such that the bulk volume (apparent volume) was 1.3 L was introduced into a ball mill having an inner diameter of 210 mm. The diameter of the ball was 10 mm.
このボールミルに、表２に示す量の、水和処理していない製鋼スラグを投入し、水量が２または４Ｌになるように水を加えた後、ボールミルを３０ｒｐｍで回転させ、回転するボールと製鋼スラグとを接触させて製鋼スラグを粉砕等した。同時に、１．５Ｌ／ｍｉｎの量の二酸化炭素を、製鋼スラグが水に懸濁したスラリーの中に導入した。
In this ball mill, the amount of steelmaking slag not subjected to hydration treatment shown in Table 2 is charged, water is added so that the amount of water is 2 or 4 L, and then the ball mill is rotated at 30 rpm to rotate the ball and steel making The steelmaking slag was crushed by bringing it into contact with the slag. At the same time, carbon dioxide in an amount of 1.5 L / min was introduced into the slurry in which steelmaking slag was suspended in water.
（カルシウム溶出量の測定）
上記Ｃａ溶出－１～Ｃａ溶出－４のいずれかの処理を６０分行った後、スラリーをろ過してスラリー中のＣＯ２水溶液を分離し、ＣＯ２水溶液中のカルシウム濃度を化学分析法によって測定した。測定されたＣＯ２水溶液中のカルシウム濃度と投入した水の量からＣＯ２水溶液中に溶出したカルシウムの量を計算し、投入した製鋼スラグ中のカルシウム量で除算して、ＣＯ２水溶液へのカルシウムの溶出率を計算した。 (Measurement of calcium elution amount)
After performing any of the above Ca elution-1 to Ca elution-4 treatment for 60 minutes, the slurry is filtered to separate the aqueous solution of CO 2 in the slurry, and the calcium concentration in the aqueous solution of CO 2 is measured by the chemical analysis method did. The amount of calcium eluted in the aqueous solution of CO 2 is calculated from the measured concentration of calcium in the aqueous solution of CO 2 and the amount of water introduced, divided by the amount of calcium in the steelmaking slag introduced, calcium to the aqueous solution of CO 2 The elution rate of was calculated.
上記Ｃａ溶出－１～Ｃａ溶出－４のいずれかの処理を６０分行った後、スラリーをろ過してスラリー中のＣＯ２水溶液を分離し、ＣＯ２水溶液中のカルシウム濃度を化学分析法によって測定した。測定されたＣＯ２水溶液中のカルシウム濃度と投入した水の量からＣＯ２水溶液中に溶出したカルシウムの量を計算し、投入した製鋼スラグ中のカルシウム量で除算して、ＣＯ２水溶液へのカルシウムの溶出率を計算した。 (Measurement of calcium elution amount)
After performing any of the above Ca elution-1 to Ca elution-4 treatment for 60 minutes, the slurry is filtered to separate the aqueous solution of CO 2 in the slurry, and the calcium concentration in the aqueous solution of CO 2 is measured by the chemical analysis method did. The amount of calcium eluted in the aqueous solution of CO 2 is calculated from the measured concentration of calcium in the aqueous solution of CO 2 and the amount of water introduced, divided by the amount of calcium in the steelmaking slag introduced, calcium to the aqueous solution of CO 2 The elution rate of was calculated.
表２に、水和の有無および水和を行った場合の水和の方法、Ｃａ溶出方法（上記Ｃａ溶出－１～Ｃａ溶出－４のいずれか）、粉砕・沈降槽またはボールミルに投入したスラグ量、ならびに上記計算により測定されたカルシウム溶出率（Ｃａ溶出率）を示す。
Table 2 shows the presence or absence of hydration and the method of hydration when hydration is carried out, the Ca elution method (any of the above Ca elution-1 to Ca elution-4), slag put into the grinding / settling tank or ball mill The amount and the calcium elution rate (Ca elution rate) measured by the above calculation are shown.
粉砕・沈降槽の内部に製鋼スラグを粉砕等する底部側の粉砕領域と、粉砕領域よりも液面に近い上部側の溶出領域を設け、粉砕領域で製鋼スラグを粉砕等しながら溶出領域で粉砕等された製鋼スラグとＣＯ２水溶液とを接触させた試験Ｎｏ．１～６および１２～１３は、Ｃａ溶出方法以外の条件（水／スラグ比など）が同一である場合で比較すると、他の方法で製鋼スラグとＣＯ２水溶液とを接触させた試験Ｎｏ．７～１１および１４～１５よりも、Ｃａ溶出率が高かった。なお、Ｃａ溶出率は製鋼スラグに対する水の量に対応する水／スラグ比が高いほど高くなった。
A grinding area on the bottom side for grinding steelmaking slag, etc. and an elution area on the upper side closer to the liquid surface than the grinding area are provided inside the grinding / settling tank, and the steelmaking slag is ground in the elution area while grinding steelmaking slag. No. 1 test in which the steelmaking slag and the CO 2 aqueous solution were brought into contact with each other. 1 to 6 and 12 to 13, when compared with the case Ca than elution method conditions (water / slag ratio, etc.) are the same, test No. is brought into contact with the steel slag and the CO 2 solution in other ways The Ca elution rate was higher than in 7-11 and 14-15. The Ca elution rate was higher as the water / slag ratio corresponding to the amount of water to steelmaking slag was higher.
特に、ＣＯ２水溶液と接触させる前に製鋼スラグに水和処理を行った試験Ｎｏ．１２～１３は、Ｃａ溶出率がより多くなった。
In particular, test No. 1 in which the steelmaking slag was subjected to hydration treatment before being brought into contact with the CO 2 aqueous solution. 12 to 13 had a higher Ca elution rate.
一方で、容器の全体で製鋼スラグを粉砕するボールミルを用いた試験Ｎｏ．７～１１では、製鋼スラグの濃度を高めても、Ｃａ溶出率が高まらなかった。
On the other hand, the test No. 1 using the ball mill which grinds steelmaking slag with the whole container. In 7 to 11, the Ca elution rate did not increase even if the concentration of steelmaking slag was increased.
［実験２］
表１に示す製鋼スラグを、直径が５ｍｍ以下になるように粉砕した。その後、粉砕された製鋼スラグを大気中で７５０℃で４０分間加熱した。加熱された製鋼スラグを冷却後にさらに粉砕した後、目開き１０６μｍの篩を通過させたものを使用した。 [Experiment 2]
The steelmaking slag shown in Table 1 was crushed so that the diameter was 5 mm or less. Thereafter, the crushed steelmaking slag was heated at 750 ° C. for 40 minutes in the atmosphere. The heated steelmaking slag was further crushed after cooling, and then passed through a sieve with an opening of 106 μm.
表１に示す製鋼スラグを、直径が５ｍｍ以下になるように粉砕した。その後、粉砕された製鋼スラグを大気中で７５０℃で４０分間加熱した。加熱された製鋼スラグを冷却後にさらに粉砕した後、目開き１０６μｍの篩を通過させたものを使用した。 [Experiment 2]
The steelmaking slag shown in Table 1 was crushed so that the diameter was 5 mm or less. Thereafter, the crushed steelmaking slag was heated at 750 ° C. for 40 minutes in the atmosphere. The heated steelmaking slag was further crushed after cooling, and then passed through a sieve with an opening of 106 μm.
上記製鋼スラグの一部を、以下の方法（磁選－１）で磁選した。その後、磁選していない製鋼スラグまたは磁選を行った製鋼スラグを、以下の方法（水和処理－２～水和処理－４のいずれか）で水和処理した。その後、水和処理していない製鋼スラグおよび上記水和処理した製鋼スラグを、実験１と同様の方法（Ｃａ溶出－１およびＣａ溶出－３のいずれか）でＣＯ２水溶液と接触させた。なお、水和処理－３または水和処理４の方法で水和処理を行ったときは、水和処理後のスラリーが含まれる同一の粉砕・沈降槽またはボールミルを用いて、さらに製鋼スラグを粉砕等しながらスラリーに二酸化炭素を導入した。その後、ＣＯ２水溶液へのカルシウムの溶出率を測定した。
A part of the steelmaking slag was magnetically separated by the following method (magnetic separation -1). Thereafter, the steelmaking slag not subjected to the magnetic separation or the steelmaking slag subjected to the magnetic separation was subjected to hydration treatment by the following method (any of hydration treatment-2 to hydration treatment-4). Thereafter, the non-hydrated steelmaking slag and the above-mentioned hydrated steelmaking slag were brought into contact with a CO 2 aqueous solution in the same manner as in Experiment 1 (either Ca elution-1 or Ca elution-3). When hydration treatment is carried out by the method of hydration treatment 3 or hydration treatment 4, the steelmaking slag is further crushed using the same grinding / settling tank or ball mill containing the slurry after hydration treatment. Carbon dioxide was introduced into the slurry while equalizing. Then, the elution rate of calcium to the CO 2 aqueous solution was measured.
（磁選）
０．１５ｋｇの上記製鋼スラグを７．５Ｌの水に懸濁させてスラリー化し、ドラム式の磁選機に投入して、ドラム表面の最大磁束密度０．０３Ｔ、ドラム周速３ｍ／ｍｉｎの条件で磁選した。磁選された後の製鋼スラグ中の鉄濃度を化学分析法によって測定したところ、最初の製鋼スラグに含まれていた鉄元素のうち３０質量％が除去されていた。 (Magnetic selection)
0.15 kg of the above steelmaking slag is suspended in 7.5 L of water to form a slurry, which is put into a drum type magnetic separator and charged with a maximum magnetic flux density of 0.03 T on the drum surface and a drum peripheral velocity of 3 m / min. I chose magnetic. The concentration of iron in the steelmaking slag after magnetic separation was measured by chemical analysis, and it was found that 30% by mass of the iron element contained in the first steelmaking slag was removed.
０．１５ｋｇの上記製鋼スラグを７．５Ｌの水に懸濁させてスラリー化し、ドラム式の磁選機に投入して、ドラム表面の最大磁束密度０．０３Ｔ、ドラム周速３ｍ／ｍｉｎの条件で磁選した。磁選された後の製鋼スラグ中の鉄濃度を化学分析法によって測定したところ、最初の製鋼スラグに含まれていた鉄元素のうち３０質量％が除去されていた。 (Magnetic selection)
0.15 kg of the above steelmaking slag is suspended in 7.5 L of water to form a slurry, which is put into a drum type magnetic separator and charged with a maximum magnetic flux density of 0.03 T on the drum surface and a drum peripheral velocity of 3 m / min. I chose magnetic. The concentration of iron in the steelmaking slag after magnetic separation was measured by chemical analysis, and it was found that 30% by mass of the iron element contained in the first steelmaking slag was removed.
（水和処理－２：ボールによる底部側での粉砕等による水和）
図１に示す構成を有する、粉砕媒体および撹拌スクリューを内部に有する内径３５０ｍｍの円筒状の粉砕・沈降槽を用意した。 (Hydration treatment 2: Hydration by grinding on the bottom side with balls, etc.)
A cylindrical grinding / settling tank having an inner diameter of 350 mm, having a grinding medium and a stirring screw inside, having the configuration shown in FIG. 1 was prepared.
図１に示す構成を有する、粉砕媒体および撹拌スクリューを内部に有する内径３５０ｍｍの円筒状の粉砕・沈降槽を用意した。 (Hydration treatment 2: Hydration by grinding on the bottom side with balls, etc.)
A cylindrical grinding / settling tank having an inner diameter of 350 mm, having a grinding medium and a stirring screw inside, having the configuration shown in FIG. 1 was prepared.
この粉砕・沈降槽に、上記磁選後の残ったスラリーおよび０．１５ｋｇの磁選を行っていない製鋼スラグのいずれかを投入し、さらに容器内の合計スラリー量が３０Ｌとなるように水を投入して製鋼スラグをスラリー状とした。その粉砕・沈降槽に、嵩体積（見かけ体積）が３．７Ｌとなる量のボール（粉砕媒体）を投入した。ボールの直径は１０ｍｍだった。その後、撹拌インペラを７０ｒｐｍで０．５時間回転させてボールを撹拌し、ボールと製鋼スラグとを接触させて製鋼スラグを粉砕等した。スラリー中への二酸化炭素の導入は行わなかった。
In the pulverization / settling tank, either the slurry after magnetic separation or 0.15 kg of steelmaking slag not subjected to magnetic separation is charged, and water is further introduced so that the total slurry amount in the container becomes 30 L. Steelmaking slag was made into slurry form. The ball (grind medium) was charged into the grinding / settling tank in an amount such that the bulk volume (apparent volume) was 3.7 L. The diameter of the ball was 10 mm. Thereafter, the stirring impeller was rotated at 70 rpm for 0.5 hour to stir the balls, and the balls and the steelmaking slag were brought into contact to grind the steelmaking slag and the like. There was no introduction of carbon dioxide into the slurry.
（水和処理－３：撹拌による水和）
撹拌インペラを有する内径３５０ｍｍの円筒状の容器に上記磁選後の残ったスラリーを投入し、さらに容器内の合計スラリー量が３０Ｌとなるように水を投入した後、撹拌インペラを３００ｒｐｍで１時間回転させた。スラリー中への二酸化炭素の導入は行わなかった。 (Hydration treatment-3: hydration by stirring)
The remaining slurry after magnetic separation is charged into a cylindrical container with an inner diameter of 350 mm having a stirring impeller, and water is further charged so that the total amount of slurry in the container is 30 L, and then the stirring impeller is rotated at 300 rpm for 1 hour I did. There was no introduction of carbon dioxide into the slurry.
撹拌インペラを有する内径３５０ｍｍの円筒状の容器に上記磁選後の残ったスラリーを投入し、さらに容器内の合計スラリー量が３０Ｌとなるように水を投入した後、撹拌インペラを３００ｒｐｍで１時間回転させた。スラリー中への二酸化炭素の導入は行わなかった。 (Hydration treatment-3: hydration by stirring)
The remaining slurry after magnetic separation is charged into a cylindrical container with an inner diameter of 350 mm having a stirring impeller, and water is further charged so that the total amount of slurry in the container is 30 L, and then the stirring impeller is rotated at 300 rpm for 1 hour I did. There was no introduction of carbon dioxide into the slurry.
（水和処理－４：ボールミルによる水和）
内径３７０ｍｍのボールミルを用意した。 (Hydration treatment 4: Hydration by ball mill)
A ball mill having an inner diameter of 370 mm was prepared.
内径３７０ｍｍのボールミルを用意した。 (Hydration treatment 4: Hydration by ball mill)
A ball mill having an inner diameter of 370 mm was prepared.
このボールミルに、０．１５ｋｇの磁選を行っていない製鋼スラグを投入し、さらに容器内の合計スラリー量が３０Ｌとなるように水を投入して製鋼スラグをスラリー状とした。その粉砕・沈降槽に、嵩体積（見かけ体積）が３．７Ｌとなる量のボール（粉砕媒体）を投入した。ボールの直径は１０ｍｍだった。その後、ボールミルを７０ｒｐｍで回転させ、回転するボールと製鋼スラグとを接触させて製鋼スラグを粉砕等した。スラリー中への二酸化炭素の導入は行わなかった。
Into this ball mill, 0.15 kg of steelmaking slag not subjected to magnetic separation was introduced, and water was further introduced so that the total amount of slurry in the container was 30 L, to make the steelmaking slag into a slurry. The ball (grind medium) was charged into the grinding / settling tank in an amount such that the bulk volume (apparent volume) was 3.7 L. The diameter of the ball was 10 mm. Thereafter, the ball mill was rotated at 70 rpm, and the rotating balls and the steelmaking slag were brought into contact with each other to grind the steelmaking slag and the like. There was no introduction of carbon dioxide into the slurry.
（カルシウム溶出量の測定）
上記Ｃａ溶出－１およびＣａ溶出－３のいずれかの処理を６０分行った後、スラリーをろ過してスラリー中のＣＯ２水溶液を分離し、ＣＯ２水溶液中のカルシウム濃度を化学分析法によって測定した。測定されたＣＯ２水溶液中のカルシウム濃度と投入した水の量からＣＯ２水溶液中に溶出したカルシウムの量を計算し、投入した製鋼スラグ中のカルシウム量で除算して、ＣＯ２水溶液へのカルシウムの溶出率を計算した。なお、磁選を行ったときは、磁選によるカルシウムの除去の影響を排除するため、ＣＯ２水溶液中に溶出したカルシウムの量を磁選後に測定した製鋼スラグ中のカルシウム量で除算して、ＣＯ２水溶液へのカルシウムの溶出率を計算した。 (Measurement of calcium elution amount)
After 60 minutes of treatment with either Ca elution-1 or Ca elution-3, the slurry is filtered to separate the aqueous solution of CO 2 in the slurry, and the calcium concentration in the aqueous solution of CO 2 is measured by chemical analysis. did. The amount of calcium eluted in the aqueous solution of CO 2 is calculated from the measured concentration of calcium in the aqueous solution of CO 2 and the amount of water introduced, divided by the amount of calcium in the steelmaking slag introduced, calcium to the aqueous solution of CO 2 The elution rate of was calculated. When the magnetic separation is performed, the amount of calcium eluted in the aqueous solution of CO 2 is divided by the amount of calcium in the steelmaking slag measured after the magnetic separation to eliminate the influence of the removal of calcium by the magnetic separation to obtain the aqueous solution of CO 2 The elution rate of calcium was calculated.
上記Ｃａ溶出－１およびＣａ溶出－３のいずれかの処理を６０分行った後、スラリーをろ過してスラリー中のＣＯ２水溶液を分離し、ＣＯ２水溶液中のカルシウム濃度を化学分析法によって測定した。測定されたＣＯ２水溶液中のカルシウム濃度と投入した水の量からＣＯ２水溶液中に溶出したカルシウムの量を計算し、投入した製鋼スラグ中のカルシウム量で除算して、ＣＯ２水溶液へのカルシウムの溶出率を計算した。なお、磁選を行ったときは、磁選によるカルシウムの除去の影響を排除するため、ＣＯ２水溶液中に溶出したカルシウムの量を磁選後に測定した製鋼スラグ中のカルシウム量で除算して、ＣＯ２水溶液へのカルシウムの溶出率を計算した。 (Measurement of calcium elution amount)
After 60 minutes of treatment with either Ca elution-1 or Ca elution-3, the slurry is filtered to separate the aqueous solution of CO 2 in the slurry, and the calcium concentration in the aqueous solution of CO 2 is measured by chemical analysis. did. The amount of calcium eluted in the aqueous solution of CO 2 is calculated from the measured concentration of calcium in the aqueous solution of CO 2 and the amount of water introduced, divided by the amount of calcium in the steelmaking slag introduced, calcium to the aqueous solution of CO 2 The elution rate of was calculated. When the magnetic separation is performed, the amount of calcium eluted in the aqueous solution of CO 2 is divided by the amount of calcium in the steelmaking slag measured after the magnetic separation to eliminate the influence of the removal of calcium by the magnetic separation to obtain the aqueous solution of CO 2 The elution rate of calcium was calculated.
表３に、磁選の有無、水和の有無および水和を行った場合の水和の方法（上記水和処理－２～水和処理－４のいずれか）、Ｃａ溶出方法（上記Ｃａ溶出－１およびＣａ溶出－３のいずれか）、ならびに上記計算により測定されたカルシウム溶出率（Ｃａ溶出率）を示す。
Table 3 shows the presence or absence of magnetic separation, the presence or absence of hydration, and the method of hydration when hydration is performed (any of the above hydration treatment-2 to hydration treatment-4), the Ca elution method (the above Ca elution 1 and Ca elution -3), and the calcium elution rate (Ca elution rate) measured by the above calculation are shown.
ＣＯ２水溶液との接触前に水和処理を行った試験Ｎｏ．２１、試験Ｎｏ．２２および試験Ｎｏ．２４は、水和処理を行わない場合よりもＣａ溶出率が高かった（特に、試験Ｎｏ．２２と試験Ｎｏ．２３との比較）。また、ＣＯ２水溶液との接触前に磁選を行った試験Ｎｏ．２２～試験Ｎｏ．２４は、磁選を行わない場合よりもＣａ溶出率が高かった（特に、試験Ｎｏ．２２と試験Ｎｏ．２１との比較）。
Test was carried out hydration treatment prior to contact with the CO 2 solution No. 21, test No. 22 and the test No. No. 24 had a higher Ca elution rate than the case without hydration treatment (in particular, comparison between Test No. 22 and Test No. 23). Furthermore, tests were conducted magnetic separation prior to contact with the CO 2 solution No. Test No. 22 to No. 22 No. 24 had a higher Ca elution rate than the case where magnetic separation was not performed (in particular, comparison between Test No. 22 and Test No. 21).
［実験３］
表１に示す製鋼スラグを、直径が５ｍｍ以下になるように粉砕した。その後、粉砕された製鋼スラグを大気中で７５０℃で４０分間加熱した。加熱された製鋼スラグを冷却後にさらに粉砕した後、目開き１０６μｍの篩を通過させたものを使用した。 [Experiment 3]
The steelmaking slag shown in Table 1 was crushed so that the diameter was 5 mm or less. Thereafter, the crushed steelmaking slag was heated at 750 ° C. for 40 minutes in the atmosphere. The heated steelmaking slag was further crushed after cooling, and then passed through a sieve with an opening of 106 μm.
表１に示す製鋼スラグを、直径が５ｍｍ以下になるように粉砕した。その後、粉砕された製鋼スラグを大気中で７５０℃で４０分間加熱した。加熱された製鋼スラグを冷却後にさらに粉砕した後、目開き１０６μｍの篩を通過させたものを使用した。 [Experiment 3]
The steelmaking slag shown in Table 1 was crushed so that the diameter was 5 mm or less. Thereafter, the crushed steelmaking slag was heated at 750 ° C. for 40 minutes in the atmosphere. The heated steelmaking slag was further crushed after cooling, and then passed through a sieve with an opening of 106 μm.
上記製鋼スラグの一部を、以下の方法（水和－５）で水和した。その後、水和を行った製鋼スラグを、以下の方法（磁選－２～磁選－３のいずれか）で磁選した。その後、磁選後に残ったスラリーを、実験１と同様の方法（Ｃａ溶出－１）でＣＯ２水溶液と接触させた。
A portion of the steelmaking slag was hydrated by the following method (hydration-5). Thereafter, the hydrated steelmaking slag was magnetically selected by the following method (one of magnetic selection-2 to magnetic selection-3). Thereafter, the slurry remaining after magnetic separation was brought into contact with a CO 2 aqueous solution in the same manner as in Experiment 1 (Ca elution-1).
（水和処理－５：ボールミルによる水和）
内径２１０ｍｍのボールミルを用意した。このボールミルに、０．１５ｋｇの磁選を行っていない製鋼スラグを投入し、さらに容器内の合計スラリー量が１Ｌとなるように水を投入して製鋼スラグをスラリー状とした。その粉砕・沈降槽に、嵩体積（見かけ体積）が１．３Ｌとなる量のボール（粉砕媒体）を投入した。ボールの直径は１０ｍｍだった。その後、ボールミルを７０ｒｐｍで回転させ、回転するボールと製鋼スラグとを接触させて製鋼スラグを粉砕等した。スラリー中への二酸化炭素の導入は行わなかった。 (Hydration treatment-5: hydration by ball mill)
A ball mill with an inner diameter of 210 mm was prepared. To this ball mill, 0.15 kg of steelmaking slag not subjected to magnetic separation was introduced, and water was further introduced such that the total amount of slurry in the container was 1 L, to make the steelmaking slag into a slurry. The ball (grind medium) of the quantity from which a bulk volume (apparent volume) will be 1.3 L was thrown into the grinding | pulverization * sedimentation tank. The diameter of the ball was 10 mm. Thereafter, the ball mill was rotated at 70 rpm, and the rotating balls and the steelmaking slag were brought into contact with each other to grind the steelmaking slag and the like. There was no introduction of carbon dioxide into the slurry.
内径２１０ｍｍのボールミルを用意した。このボールミルに、０．１５ｋｇの磁選を行っていない製鋼スラグを投入し、さらに容器内の合計スラリー量が１Ｌとなるように水を投入して製鋼スラグをスラリー状とした。その粉砕・沈降槽に、嵩体積（見かけ体積）が１．３Ｌとなる量のボール（粉砕媒体）を投入した。ボールの直径は１０ｍｍだった。その後、ボールミルを７０ｒｐｍで回転させ、回転するボールと製鋼スラグとを接触させて製鋼スラグを粉砕等した。スラリー中への二酸化炭素の導入は行わなかった。 (Hydration treatment-5: hydration by ball mill)
A ball mill with an inner diameter of 210 mm was prepared. To this ball mill, 0.15 kg of steelmaking slag not subjected to magnetic separation was introduced, and water was further introduced such that the total amount of slurry in the container was 1 L, to make the steelmaking slag into a slurry. The ball (grind medium) of the quantity from which a bulk volume (apparent volume) will be 1.3 L was thrown into the grinding | pulverization * sedimentation tank. The diameter of the ball was 10 mm. Thereafter, the ball mill was rotated at 70 rpm, and the rotating balls and the steelmaking slag were brought into contact with each other to grind the steelmaking slag and the like. There was no introduction of carbon dioxide into the slurry.
（磁選－２）
上記水和処理したスラリーに水を加え合計水量を４Ｌにしたのち、ドラム式の磁選機に投入して、ドラム表面の最大磁束密度０．０３Ｔ、ドラム周速４ｍ／ｍｉｎの条件で磁選した。磁選された後の製鋼スラグ中の鉄濃度を化学分析法によって測定したところ、最初の製鋼スラグに含まれていた鉄元素のうち３５質量％が除去されていた。 (Selection-2)
Water was added to the hydrated slurry to make the total amount of water 4 L, and then it was put into a drum type magnetic separator to conduct magnetic separation under the conditions of a maximum magnetic flux density of 0.03 T on the drum surface and a drum peripheral speed of 4 m / min. When the iron concentration in steelmaking slag after being magnetically separated was measured by a chemical analysis method, 35% by mass of the iron element contained in the first steelmaking slag was removed.
上記水和処理したスラリーに水を加え合計水量を４Ｌにしたのち、ドラム式の磁選機に投入して、ドラム表面の最大磁束密度０．０３Ｔ、ドラム周速４ｍ／ｍｉｎの条件で磁選した。磁選された後の製鋼スラグ中の鉄濃度を化学分析法によって測定したところ、最初の製鋼スラグに含まれていた鉄元素のうち３５質量％が除去されていた。 (Selection-2)
Water was added to the hydrated slurry to make the total amount of water 4 L, and then it was put into a drum type magnetic separator to conduct magnetic separation under the conditions of a maximum magnetic flux density of 0.03 T on the drum surface and a drum peripheral speed of 4 m / min. When the iron concentration in steelmaking slag after being magnetically separated was measured by a chemical analysis method, 35% by mass of the iron element contained in the first steelmaking slag was removed.
（磁選－３）
上記水和処理したスラリーに水を加え合計水量が７．５Ｌにしたのち、ドラム式の磁選機に投入して、ドラム表面の最大磁束密度０．０３Ｔ、ドラム周速４ｍ／ｍｉｎの条件で磁選した。磁選された後の製鋼スラグ中の鉄濃度を化学分析法によって測定したところ、最初の製鋼スラグに含まれていた鉄元素のうち３７質量％が除去されていた。 (Select magnetic-3)
Water is added to the above-mentioned hydrated slurry to make the total water volume 7.5 L, and then it is put into a drum type magnetic separator, and magnetic separation is performed under the conditions of the maximum magnetic flux density of 0.03 T on the drum surface and the drum peripheral speed 4 m / min. did. The concentration of iron in the steelmaking slag after magnetic separation was measured by chemical analysis, and it was found that 37% by mass of the iron element contained in the first steelmaking slag was removed.
上記水和処理したスラリーに水を加え合計水量が７．５Ｌにしたのち、ドラム式の磁選機に投入して、ドラム表面の最大磁束密度０．０３Ｔ、ドラム周速４ｍ／ｍｉｎの条件で磁選した。磁選された後の製鋼スラグ中の鉄濃度を化学分析法によって測定したところ、最初の製鋼スラグに含まれていた鉄元素のうち３７質量％が除去されていた。 (Select magnetic-3)
Water is added to the above-mentioned hydrated slurry to make the total water volume 7.5 L, and then it is put into a drum type magnetic separator, and magnetic separation is performed under the conditions of the maximum magnetic flux density of 0.03 T on the drum surface and the drum peripheral speed 4 m / min. did. The concentration of iron in the steelmaking slag after magnetic separation was measured by chemical analysis, and it was found that 37% by mass of the iron element contained in the first steelmaking slag was removed.
表４に、上記水和、磁選を行った場合のカルシウム溶出率（Ｃａ溶出率）を示す。溶出率の算出方法は、実験１および２と同様とした。
Table 4 shows the calcium elution rate (Ca elution rate) when the above hydration and magnetic separation were performed. The method of calculating the dissolution rate was the same as in Experiments 1 and 2.
水和処理を行った後に磁選を行った試験Ｎｏ．３１～３２は、いずれもＣａ溶出率が高かった。
The test No. 1 which performed magnetic selection after performing a hydration process. All of 31 to 32 had high Ca elution rates.
本出願は、２０１７年１１月３０日出願の日本国出願番号２０１７－２３１０２０号に基づく優先権を主張する出願であり、当該出願の特許請求の範囲、明細書および図面に記載された内容は本出願に援用される。
This application is an application claiming priority based on Japanese Patent Application No. 2017-231020 filed on November 30, 2017, and the contents described in the claims, specification and drawings of the application are the contents of this application. It is incorporated into the application.
本発明に係るカルシウムを溶出させる方法は、二酸化炭素を含有する水溶液への製鋼スラグ中のカルシウムの溶出量を容易に高めることができるため、製鉄におけるカルシウム資源の回収方法として有用である。
The method for eluting calcium according to the present invention is useful as a method for recovering calcium resources in steelmaking because it can easily increase the elution amount of calcium in steelmaking slag to an aqueous solution containing carbon dioxide.
１００、２００、３００、５００ 製鋼スラグからカルシウムを溶出させる装置
１１０、２１０、３１０、５１０ 粉砕・沈降槽
１２０、２２０，３２０ 粉砕機構
１２２、２２２、３２２ 粉砕媒体
１２４、２２４、３２４ 撹拌機構
１２４ａ、２２４ａ 撹拌インペラ
１２４ｂ 撹拌スクリュー
１２４ｃ、２２４ｃ、３２４ｃ 回転軸体
１３０、２３０、３３０、５３０ 二酸化炭素導入部
１３２、２３２、３３２ 流路
１３４、２３４、３３４、５３４ 導入口
３２４ｄ 撹拌棒支持体
３２４ｅ 撹拌棒
５３５ 循環型の流路
５３６ ポンプ 100, 200, 300, 500 Apparatus for eluting calcium from steelmaking slag 110, 210, 310, 510 Grinding and settling tank 120, 220, 320 Grinding mechanism 122, 222, 322 Grinding medium 124, 224, 324 Stirring mechanism 124a, 224a Stir impeller 124b Stir screw 124c, 224c, 324c Rotatable body 130, 230, 330, 530 Carbon dioxide introduction part 132, 232, 332 Flow path 134, 234, 334, 534 Introduction port 324d Stir bar support 324e Stir bar 535 circulation Mold flow path 536 pump
１１０、２１０、３１０、５１０ 粉砕・沈降槽
１２０、２２０，３２０ 粉砕機構
１２２、２２２、３２２ 粉砕媒体
１２４、２２４、３２４ 撹拌機構
１２４ａ、２２４ａ 撹拌インペラ
１２４ｂ 撹拌スクリュー
１２４ｃ、２２４ｃ、３２４ｃ 回転軸体
１３０、２３０、３３０、５３０ 二酸化炭素導入部
１３２、２３２、３３２ 流路
１３４、２３４、３３４、５３４ 導入口
３２４ｄ 撹拌棒支持体
３２４ｅ 撹拌棒
５３５ 循環型の流路
５３６ ポンプ 100, 200, 300, 500 Apparatus for eluting calcium from
Claims (13)
- 粉砕・沈降槽の内部の液面に近い上部側の領域における製鋼スラグを含むスラリーの撹拌を抑制して前記製鋼スラグを沈降させつつ、前記粉砕・沈降槽の内部の底部側の領域で前記スラリーに含まれる製鋼スラグを粉砕または前記製鋼スラグの表面を磨砕する工程と、
前記スラリーに二酸化炭素を導入して、前記粉砕または磨砕された製鋼スラグと前記二酸化炭素が溶解した水溶液とを接触させる工程と、を含む、
製鋼スラグからカルシウムを溶出させる方法。 Stirring of the slurry containing steelmaking slag in the region on the upper side close to the liquid level inside the crushing and settling tank is suppressed to precipitate the steelmaking slag, and the slurry in the region on the bottom side inside the crushing and settling tank Grinding the steelmaking slag contained in the steel or grinding the surface of the steelmaking slag;
Introducing carbon dioxide into the slurry to bring the crushed or ground steelmaking slag into contact with an aqueous solution in which the carbon dioxide is dissolved.
Method to elute calcium from steelmaking slag. - 前記スラリーに含まれる製鋼スラグは、前記粉砕・沈降槽の内部の底部側に配置された撹拌機構により前記上部側の領域への移動が抑制されるように流動された粉砕媒体との接触によって、粉砕または磨砕される、請求項１に記載の製鋼スラグからカルシウムを溶出させる方法。 The steelmaking slag contained in the slurry is brought into contact with the grinding medium which is flowed so as to suppress the movement to the region on the upper side by the stirring mechanism disposed on the bottom side inside the grinding / settling tank, The method of eluting calcium from steelmaking slag according to claim 1, which is crushed or ground.
- 前記撹拌機構は、
回転軸体と、
前記回転軸体から前記粉砕・沈降槽の深さ方向に略直交する方向に延出する撹拌棒支持体と、
前記撹拌棒支持体に支持されて前記粉砕・沈降槽の深さ方向に延出し、前記回転軸体の回転によって回転して前記粉砕媒体を流動させる撹拌棒と、
を有する、請求項２に記載の製鋼スラグからカルシウムを溶出させる方法。 The stirring mechanism is
A rotating shaft,
A stirring rod support extending from the rotating shaft in a direction substantially orthogonal to the depth direction of the crushing / settling tank;
A stirring rod supported by the stirring rod support and extending in the depth direction of the grinding / settling tank, and rotated by rotation of the rotary shaft to flow the grinding medium;
The method for eluting calcium from steelmaking slag according to claim 2, comprising - 前記二酸化炭素は、前記撹拌機構から前記スラリーに導入される、請求項２または３に記載の製鋼スラグからカルシウムを溶出させる方法。 The method for eluting calcium from steelmaking slag according to claim 2 or 3, wherein the carbon dioxide is introduced into the slurry from the stirring mechanism.
- 前記二酸化炭素は、前記粉砕・沈降槽の外部に配置された二酸化炭素導入部により前記スラリーに導入される、請求項２～４のいずれか１項に記載の製鋼スラグからカルシウムを溶出させる方法。 The method for eluting calcium from steelmaking slag according to any one of claims 2 to 4, wherein the carbon dioxide is introduced into the slurry by a carbon dioxide introduction unit disposed outside the crushing / settling tank.
- 前記粉砕・沈降槽における沈降および粉砕または磨砕を経ていない製鋼スラグを含むスラリーを前記粉砕・沈降槽に導入する工程を有し、
前記導入されるスラリーに含まれる製鋼スラグは、水和処理された製鋼スラグである、
請求項１～５のいずれか１項に記載の製鋼スラグからカルシウムを溶出させる方法。 Introducing a slurry containing steelmaking slag which has not been subjected to sedimentation and grinding or grinding in the grinding / settling tank to the grinding / settling tank,
The steelmaking slag contained in the introduced slurry is a hydrated steelmaking slag,
A method of eluting calcium from steelmaking slag according to any one of claims 1 to 5. - 前記粉砕・沈降槽における沈降および粉砕または磨砕を経ていない製鋼スラグを含むスラリーを前記粉砕・沈降槽に導入する工程を有し、
前記導入されるスラリーに含まれる製鋼スラグは、磁選された製鋼スラグである、
請求項１～６のいずれか１項に記載の製鋼スラグからカルシウムを溶出させる方法。 Introducing a slurry containing steelmaking slag which has not been subjected to sedimentation and grinding or grinding in the grinding / settling tank to the grinding / settling tank,
The steelmaking slag contained in the introduced slurry is a magnetically selected steelmaking slag,
A method of eluting calcium from steelmaking slag according to any one of claims 1 to 6. - 請求項１～７のいずれか１項に記載の製鋼スラグからカルシウムを溶出させる方法により製鋼スラグからカルシウムを溶出させる工程と、
前記溶出したカルシウムを回収する工程とを含む、
製鋼スラグからカルシウムを回収する方法。 A process of eluting calcium from steelmaking slag by the method of eluting calcium from steelmaking slag according to any one of claims 1 to 7,
And collecting the eluted calcium.
How to recover calcium from steelmaking slag. - 製鋼スラグを含むスラリーが投入される粉砕・沈降槽と、
前記粉砕・沈降槽の内部の底部側の領域に配置され、前記粉砕・沈降槽の内部の液面に近い上部側の領域における前記スラリーの撹拌が抑制されて前記製鋼スラグが沈降するように、前記底部側の領域で前記スラリーに含まれる製鋼スラグを粉砕または前記製鋼スラグの表面を磨砕する粉砕機構と、
前記粉砕機構による粉砕または磨砕と同時に、前記スラリーに二酸化炭素を導入する二酸化炭素導入部と、を含む、
製鋼スラグからカルシウムを溶出させる装置。 A grinding and settling tank into which a slurry containing steelmaking slag is charged;
The stirring of the slurry in the region on the upper side closer to the liquid surface inside the crushing and settling tank is suppressed so that the steelmaking slag is settled, which is disposed in the region on the bottom side inside the crushing and settling tank, A grinding mechanism for grinding the steelmaking slag contained in the slurry in the region on the bottom side or grinding the surface of the steelmaking slag;
A carbon dioxide introduction unit for introducing carbon dioxide into the slurry simultaneously with grinding or grinding by the grinding mechanism;
Equipment to elute calcium from steelmaking slag. - 前記粉砕機構は、
前記粉砕・沈降槽の内部に配置された撹拌機構と、
前記上部側の領域への移動が抑制されるように前記撹拌機構により流動され、前記スラリーに含まれる製鋼スラグと接触して前記製鋼スラグを粉砕または前記製鋼スラグの表面を磨砕する粉砕媒体と、
を有する、請求項９に記載の製鋼スラグからカルシウムを溶出させる装置。 The crushing mechanism is
A stirring mechanism disposed inside the grinding / settling tank,
Pulverizing medium which is fluidized by the stirring mechanism so as to suppress the movement to the upper side region, and which is in contact with the steelmaking slag contained in the slurry to grind the steelmaking slag or grind the surface of the steelmaking slag ,
The apparatus for eluting calcium from steelmaking slag according to claim 9, comprising: - 前記撹拌機構は、
回転軸体と、
前記回転軸体から前記粉砕・沈降槽の深さ方向に略直交する方向に延出する撹拌棒支持体と、
前記撹拌棒支持体に支持されて前記粉砕・沈降槽の深さ方向に延出し、前記回転軸体の回転によって回転して前記粉砕媒体を流動させる撹拌棒と、
を有する、請求項１０に記載の製鋼スラグからカルシウムを溶出させる装置。 The stirring mechanism is
A rotating shaft,
A stirring rod support extending from the rotating shaft in a direction substantially orthogonal to the depth direction of the crushing / settling tank;
A stirring rod supported by the stirring rod support and extending in the depth direction of the grinding / settling tank, and rotated by rotation of the rotary shaft to flow the grinding medium;
The apparatus for eluting calcium from steelmaking slag according to claim 10, comprising: - 前記二酸化炭素導入部は、前記撹拌機構から前記スラリーに二酸化炭素を導入する構成を有する、請求項１０または１１に記載の製鋼スラグからカルシウムを溶出させる装置。 The apparatus for eluting calcium from steelmaking slag according to claim 10, wherein the carbon dioxide introduction unit has a configuration for introducing carbon dioxide into the slurry from the stirring mechanism.
- 前記二酸化炭素導入部は、前記粉砕・沈降槽の外部に配置された、請求項１０または１１に記載の製鋼スラグからカルシウムを溶出させる装置。 The apparatus for eluting calcium from steelmaking slag according to claim 10, wherein the carbon dioxide introduction unit is disposed outside the crushing and settling tank.
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| WO2010110088A1 (en) * | 2009-03-25 | 2010-09-30 | 国立大学法人東京大学 | Fluorite purification method |
| JP2011016710A (en) * | 2009-06-08 | 2011-01-27 | Kobe Steel Ltd | Carbonation treatment method and apparatus of steel slag powder |
| JP2011093761A (en) * | 2009-10-30 | 2011-05-12 | Jfe Steel Corp | Method for treating slag containing sulfur and calcium |
| JP2011093760A (en) * | 2009-10-30 | 2011-05-12 | Jfe Steel Corp | Method for treating sulfur-containing slag |
| JP2016179909A (en) * | 2015-03-23 | 2016-10-13 | 日新製鋼株式会社 | Method for recovering calcium-containing solid component from steel slag, and recovered solid component |
| WO2017163595A1 (en) * | 2016-03-24 | 2017-09-28 | 日新製鋼株式会社 | Method for eluting calcium from steel slag and method for recovering calcium from steel slag |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2010110088A1 (en) * | 2009-03-25 | 2010-09-30 | 国立大学法人東京大学 | Fluorite purification method |
| JP2011016710A (en) * | 2009-06-08 | 2011-01-27 | Kobe Steel Ltd | Carbonation treatment method and apparatus of steel slag powder |
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| JP2011093760A (en) * | 2009-10-30 | 2011-05-12 | Jfe Steel Corp | Method for treating sulfur-containing slag |
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