WO2022014234A1 - Method for recovering scandium - Google Patents
Method for recovering scandium Download PDFInfo
- Publication number
- WO2022014234A1 WO2022014234A1 PCT/JP2021/022555 JP2021022555W WO2022014234A1 WO 2022014234 A1 WO2022014234 A1 WO 2022014234A1 JP 2021022555 W JP2021022555 W JP 2021022555W WO 2022014234 A1 WO2022014234 A1 WO 2022014234A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- scandium
- solution
- treatment
- oxalate
- oxalic acid
- Prior art date
Links
- 229910052706 scandium Inorganic materials 0.000 title claims abstract description 202
- SIXSYDAISGFNSX-UHFFFAOYSA-N scandium atom Chemical compound [Sc] SIXSYDAISGFNSX-UHFFFAOYSA-N 0.000 title claims abstract description 201
- 238000000034 method Methods 0.000 title claims abstract description 83
- MUBZPKHOEPUJKR-UHFFFAOYSA-N Oxalic acid Chemical compound OC(=O)C(O)=O MUBZPKHOEPUJKR-UHFFFAOYSA-N 0.000 claims abstract description 232
- 239000000243 solution Substances 0.000 claims abstract description 147
- 238000011282 treatment Methods 0.000 claims abstract description 101
- 239000012535 impurity Substances 0.000 claims abstract description 93
- 235000006408 oxalic acid Nutrition 0.000 claims abstract description 71
- 238000006243 chemical reaction Methods 0.000 claims abstract description 53
- OMMFSGNJZPSNEH-UHFFFAOYSA-H oxalate;scandium(3+) Chemical compound [Sc+3].[Sc+3].[O-]C(=O)C([O-])=O.[O-]C(=O)C([O-])=O.[O-]C(=O)C([O-])=O OMMFSGNJZPSNEH-UHFFFAOYSA-H 0.000 claims abstract description 43
- 229910052751 metal Inorganic materials 0.000 claims abstract description 29
- 239000003929 acidic solution Substances 0.000 claims abstract description 12
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 63
- 238000007254 oxidation reaction Methods 0.000 claims description 48
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims description 46
- 230000003647 oxidation Effects 0.000 claims description 43
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 30
- 229910052759 nickel Inorganic materials 0.000 claims description 30
- 229910000480 nickel oxide Inorganic materials 0.000 claims description 20
- GNRSAWUEBMWBQH-UHFFFAOYSA-N oxonickel Chemical compound [Ni]=O GNRSAWUEBMWBQH-UHFFFAOYSA-N 0.000 claims description 20
- 239000002184 metal Substances 0.000 claims description 19
- 238000011084 recovery Methods 0.000 claims description 18
- 238000010306 acid treatment Methods 0.000 claims description 17
- 239000003795 chemical substances by application Substances 0.000 claims description 15
- 229910052742 iron Inorganic materials 0.000 claims description 15
- 238000002386 leaching Methods 0.000 claims description 13
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 claims description 9
- 239000011572 manganese Substances 0.000 claims description 9
- 239000007800 oxidant agent Substances 0.000 claims description 7
- 229910052748 manganese Inorganic materials 0.000 claims description 5
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 claims description 4
- CZMRCDWAGMRECN-UGDNZRGBSA-N Sucrose Chemical compound O[C@H]1[C@H](O)[C@@H](CO)O[C@@]1(CO)O[C@@H]1[C@H](O)[C@@H](O)[C@H](O)[C@@H](CO)O1 CZMRCDWAGMRECN-UGDNZRGBSA-N 0.000 claims description 3
- 229930006000 Sucrose Natural products 0.000 claims description 3
- 239000005720 sucrose Substances 0.000 claims description 3
- MVWDJLOUEUAWIE-UHFFFAOYSA-N O=C=O.O=C=O Chemical compound O=C=O.O=C=O MVWDJLOUEUAWIE-UHFFFAOYSA-N 0.000 abstract 2
- 239000007788 liquid Substances 0.000 description 43
- 238000000605 extraction Methods 0.000 description 34
- 239000011347 resin Substances 0.000 description 25
- 229920005989 resin Polymers 0.000 description 25
- 239000013522 chelant Substances 0.000 description 24
- 238000005342 ion exchange Methods 0.000 description 24
- 239000003960 organic solvent Substances 0.000 description 21
- 238000000638 solvent extraction Methods 0.000 description 21
- 229910052782 aluminium Inorganic materials 0.000 description 16
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 16
- 239000013078 crystal Substances 0.000 description 16
- 238000005987 sulfurization reaction Methods 0.000 description 16
- 239000003480 eluent Substances 0.000 description 15
- 238000006386 neutralization reaction Methods 0.000 description 12
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 11
- 238000005406 washing Methods 0.000 description 11
- 239000011651 chromium Substances 0.000 description 10
- HYXGAEYDKFCVMU-UHFFFAOYSA-N scandium oxide Chemical compound O=[Sc]O[Sc]=O HYXGAEYDKFCVMU-UHFFFAOYSA-N 0.000 description 10
- 238000005201 scrubbing Methods 0.000 description 10
- 239000002002 slurry Substances 0.000 description 10
- 229910052804 chromium Inorganic materials 0.000 description 9
- 238000002425 crystallisation Methods 0.000 description 8
- 230000008025 crystallization Effects 0.000 description 8
- 239000002244 precipitate Substances 0.000 description 8
- 238000000926 separation method Methods 0.000 description 8
- WWNBZGLDODTKEM-UHFFFAOYSA-N sulfanylidenenickel Chemical compound [Ni]=S WWNBZGLDODTKEM-UHFFFAOYSA-N 0.000 description 8
- 150000001412 amines Chemical class 0.000 description 7
- 238000004140 cleaning Methods 0.000 description 7
- 238000009854 hydrometallurgy Methods 0.000 description 7
- OWZIYWAUNZMLRT-UHFFFAOYSA-L iron(2+);oxalate Chemical compound [Fe+2].[O-]C(=O)C([O-])=O OWZIYWAUNZMLRT-UHFFFAOYSA-L 0.000 description 7
- 238000001556 precipitation Methods 0.000 description 7
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 7
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 description 6
- 230000003472 neutralizing effect Effects 0.000 description 6
- 238000001179 sorption measurement Methods 0.000 description 6
- 229920002472 Starch Polymers 0.000 description 5
- 238000010828 elution Methods 0.000 description 5
- 239000008107 starch Substances 0.000 description 5
- 235000019698 starch Nutrition 0.000 description 5
- 238000005486 sulfidation Methods 0.000 description 5
- 239000002562 thickening agent Substances 0.000 description 5
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 4
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 4
- 238000003723 Smelting Methods 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 4
- 229910017052 cobalt Inorganic materials 0.000 description 4
- 239000010941 cobalt Substances 0.000 description 4
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 4
- 239000012141 concentrate Substances 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 4
- -1 nickel salt compounds Chemical class 0.000 description 4
- 238000003756 stirring Methods 0.000 description 4
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 3
- 230000007423 decrease Effects 0.000 description 3
- 238000001914 filtration Methods 0.000 description 3
- 239000011777 magnesium Substances 0.000 description 3
- 150000002739 metals Chemical class 0.000 description 3
- XTAZYLNFDRKIHJ-UHFFFAOYSA-N n,n-dioctyloctan-1-amine Chemical compound CCCCCCCCN(CCCCCCCC)CCCCCCCC XTAZYLNFDRKIHJ-UHFFFAOYSA-N 0.000 description 3
- 239000000047 product Substances 0.000 description 3
- 229910052761 rare earth metal Inorganic materials 0.000 description 3
- 239000007858 starting material Substances 0.000 description 3
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 2
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 2
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 2
- 229910021607 Silver chloride Inorganic materials 0.000 description 2
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 2
- 239000002253 acid Substances 0.000 description 2
- 230000002378 acidificating effect Effects 0.000 description 2
- 239000008346 aqueous phase Substances 0.000 description 2
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 description 2
- 239000000920 calcium hydroxide Substances 0.000 description 2
- 229910001861 calcium hydroxide Inorganic materials 0.000 description 2
- 235000011116 calcium hydroxide Nutrition 0.000 description 2
- 229910052595 hematite Inorganic materials 0.000 description 2
- 239000011019 hematite Substances 0.000 description 2
- 229910052500 inorganic mineral Inorganic materials 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
- 229910001710 laterite Inorganic materials 0.000 description 2
- 239000011504 laterite Substances 0.000 description 2
- 229910052749 magnesium Inorganic materials 0.000 description 2
- 239000012528 membrane Substances 0.000 description 2
- 239000011707 mineral Substances 0.000 description 2
- 235000010755 mineral Nutrition 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 239000012074 organic phase Substances 0.000 description 2
- 230000001376 precipitating effect Effects 0.000 description 2
- LQPWUWOODZHKKW-UHFFFAOYSA-K scandium(3+);trihydroxide Chemical compound [OH-].[OH-].[OH-].[Sc+3] LQPWUWOODZHKKW-UHFFFAOYSA-K 0.000 description 2
- 229910052709 silver Inorganic materials 0.000 description 2
- 239000004332 silver Substances 0.000 description 2
- HKZLPVFGJNLROG-UHFFFAOYSA-M silver monochloride Chemical compound [Cl-].[Ag+] HKZLPVFGJNLROG-UHFFFAOYSA-M 0.000 description 2
- 238000000967 suction filtration Methods 0.000 description 2
- 150000004763 sulfides Chemical class 0.000 description 2
- 229910021653 sulphate ion Inorganic materials 0.000 description 2
- NWUYHJFMYQTDRP-UHFFFAOYSA-N 1,2-bis(ethenyl)benzene;1-ethenyl-2-ethylbenzene;styrene Chemical compound C=CC1=CC=CC=C1.CCC1=CC=CC=C1C=C.C=CC1=CC=CC=C1C=C NWUYHJFMYQTDRP-UHFFFAOYSA-N 0.000 description 1
- RSWGJHLUYNHPMX-UHFFFAOYSA-N 1,4a-dimethyl-7-propan-2-yl-2,3,4,4b,5,6,10,10a-octahydrophenanthrene-1-carboxylic acid Chemical compound C12CCC(C(C)C)=CC2=CCC2C1(C)CCCC2(C)C(O)=O RSWGJHLUYNHPMX-UHFFFAOYSA-N 0.000 description 1
- 229910000838 Al alloy Inorganic materials 0.000 description 1
- UIXOHXMSPVARMA-UHFFFAOYSA-N C(C(=O)O)(=[O+][O-])O Chemical compound C(C(=O)O)(=[O+][O-])O UIXOHXMSPVARMA-UHFFFAOYSA-N 0.000 description 1
- 239000004215 Carbon black (E152) Substances 0.000 description 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- RWSOTUBLDIXVET-UHFFFAOYSA-N Dihydrogen sulfide Chemical compound S RWSOTUBLDIXVET-UHFFFAOYSA-N 0.000 description 1
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 description 1
- 235000019738 Limestone Nutrition 0.000 description 1
- 229910021586 Nickel(II) chloride Inorganic materials 0.000 description 1
- 240000007594 Oryza sativa Species 0.000 description 1
- 235000007164 Oryza sativa Nutrition 0.000 description 1
- 240000007019 Oxalis corniculata Species 0.000 description 1
- 235000016499 Oxalis corniculata Nutrition 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 1
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 1
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 238000010790 dilution Methods 0.000 description 1
- 239000012895 dilution Substances 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000003792 electrolyte Substances 0.000 description 1
- VEPSWGHMGZQCIN-UHFFFAOYSA-H ferric oxalate Chemical compound [Fe+3].[Fe+3].[O-]C(=O)C([O-])=O.[O-]C(=O)C([O-])=O.[O-]C(=O)C([O-])=O VEPSWGHMGZQCIN-UHFFFAOYSA-H 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 125000000524 functional group Chemical group 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 229910000037 hydrogen sulfide Inorganic materials 0.000 description 1
- NBZBKCUXIYYUSX-UHFFFAOYSA-N iminodiacetic acid Chemical compound OC(=O)CNCC(O)=O NBZBKCUXIYYUSX-UHFFFAOYSA-N 0.000 description 1
- 239000003456 ion exchange resin Substances 0.000 description 1
- 229920003303 ion-exchange polymer Polymers 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 239000006028 limestone Substances 0.000 description 1
- HCWCAKKEBCNQJP-UHFFFAOYSA-N magnesium orthosilicate Chemical compound [Mg+2].[Mg+2].[O-][Si]([O-])([O-])[O-] HCWCAKKEBCNQJP-UHFFFAOYSA-N 0.000 description 1
- 239000000391 magnesium silicate Substances 0.000 description 1
- 229910052919 magnesium silicate Inorganic materials 0.000 description 1
- 235000019792 magnesium silicate Nutrition 0.000 description 1
- WPBNNNQJVZRUHP-UHFFFAOYSA-L manganese(2+);methyl n-[[2-(methoxycarbonylcarbamothioylamino)phenyl]carbamothioyl]carbamate;n-[2-(sulfidocarbothioylamino)ethyl]carbamodithioate Chemical compound [Mn+2].[S-]C(=S)NCCNC([S-])=S.COC(=O)NC(=S)NC1=CC=CC=C1NC(=S)NC(=O)OC WPBNNNQJVZRUHP-UHFFFAOYSA-L 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 125000000896 monocarboxylic acid group Chemical group 0.000 description 1
- QMMRZOWCJAIUJA-UHFFFAOYSA-L nickel dichloride Chemical compound Cl[Ni]Cl QMMRZOWCJAIUJA-UHFFFAOYSA-L 0.000 description 1
- LGQLOGILCSXPEA-UHFFFAOYSA-L nickel sulfate Chemical compound [Ni+2].[O-]S([O-])(=O)=O LGQLOGILCSXPEA-UHFFFAOYSA-L 0.000 description 1
- 229910000363 nickel(II) sulfate Inorganic materials 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 239000012071 phase Substances 0.000 description 1
- 238000005191 phase separation Methods 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 150000003141 primary amines Chemical class 0.000 description 1
- 150000002910 rare earth metals Chemical class 0.000 description 1
- 235000009566 rice Nutrition 0.000 description 1
- 150000003325 scandium Chemical class 0.000 description 1
- CAKRPOQJQRDOIT-UHFFFAOYSA-N scandium sulfuric acid Chemical compound [Sc].S(O)(O)(=O)=O CAKRPOQJQRDOIT-UHFFFAOYSA-N 0.000 description 1
- 150000003335 secondary amines Chemical class 0.000 description 1
- 239000013049 sediment Substances 0.000 description 1
- 238000004062 sedimentation Methods 0.000 description 1
- 229910000029 sodium carbonate Inorganic materials 0.000 description 1
- 235000011121 sodium hydroxide Nutrition 0.000 description 1
- HYHCSLBZRBJJCH-UHFFFAOYSA-N sodium polysulfide Chemical compound [Na+].S HYHCSLBZRBJJCH-UHFFFAOYSA-N 0.000 description 1
- 229910052979 sodium sulfide Inorganic materials 0.000 description 1
- GRVFOGOEDUUMBP-UHFFFAOYSA-N sodium sulfide (anhydrous) Chemical compound [Na+].[Na+].[S-2] GRVFOGOEDUUMBP-UHFFFAOYSA-N 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 238000002798 spectrophotometry method Methods 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000011593 sulfur Substances 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
- 239000006228 supernatant Substances 0.000 description 1
- 150000003512 tertiary amines Chemical class 0.000 description 1
- 229910052718 tin Inorganic materials 0.000 description 1
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 239000010937 tungsten Substances 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
- 239000011701 zinc Substances 0.000 description 1
- 229910052726 zirconium Inorganic materials 0.000 description 1
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
- C07C51/42—Separation; Purification; Stabilisation; Use of additives
- C07C51/487—Separation; Purification; Stabilisation; Use of additives by treatment giving rise to chemical modification
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C55/00—Saturated compounds having more than one carboxyl group bound to acyclic carbon atoms
- C07C55/02—Dicarboxylic acids
- C07C55/06—Oxalic acid
- C07C55/07—Salts thereof
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07F—ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM
- C07F5/00—Compounds containing elements of Groups 3 or 13 of the Periodic Table
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B3/00—Extraction of metal compounds from ores or concentrates by wet processes
- C22B3/04—Extraction of metal compounds from ores or concentrates by wet processes by leaching
- C22B3/06—Extraction of metal compounds from ores or concentrates by wet processes by leaching in inorganic acid solutions, e.g. with acids generated in situ; in inorganic salt solutions other than ammonium salt solutions
- C22B3/08—Sulfuric acid, other sulfurated acids or salts thereof
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B3/00—Extraction of metal compounds from ores or concentrates by wet processes
- C22B3/20—Treatment or purification of solutions, e.g. obtained by leaching
- C22B3/44—Treatment or purification of solutions, e.g. obtained by leaching by chemical processes
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B59/00—Obtaining rare earth metals
-
- 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 for recovering scandium. More specifically, the present invention relates to a method for recovering scandium, which selectively recovers scandium from an acidic sulfuric acid solution containing impurities.
- Scandium is known to be extremely useful as an additive element for aluminum alloys and as an electrolyte for fuel cells. However, it has not been widely used because of its low production volume and high cost.
- Scandium has a particularly small ionic radius among rare earth elements, and is rarely present in ordinary rare earth minerals. Instead, it is known to be widely present in trace amounts in oxide ores of aluminum, tin, tungsten, zirconium, iron, nickel and the like.
- the HPAL process has been put into practical use, in which nickel oxide ore is charged into a pressure vessel together with sulfuric acid and heated to a high temperature to solid-liquid separation into a nickel-containing leachate and a leachate residue.
- a neutralizing agent is added to the leachate obtained by the HPAL process to separate impurities, and a sulfurizing agent is further added to recover nickel as nickel sulfide.
- nickel salt compounds such as electric nickel, nickel sulfate, and nickel chloride can be obtained.
- the scandium contained in the nickel oxide ore is leached together with nickel and contained in the leachate, for example, as shown in Patent Document 1.
- a neutralizing agent is added to the leachate to separate impurities and then a sulfide agent is added, nickel is recovered as nickel sulfide, and scandium does not form sulfide and is an acidic solution after addition of the sulfide agent (sulfuric acid). Included in acidic solution).
- the sulfide agent sulfuric acid
- the scandium concentration in the sulfuric acid acidic solution is dilute (several tens of mg / L), and other impurities such as iron and aluminum are contained in a much larger amount.
- a method of selectively recovering and concentrating scandium by an adsorption method using an ion exchange resin or a solvent extraction method is used. After that, in order to further improve the scandium quality, an alkali is added to the concentrated scandium solution to cause a crystallization reaction to form a hydroxide, or oxalic acid is added to crystallize the oxalic acid. It is recovered by processing such as analysis.
- the method of crystallizing scandium as a hydroxide has a problem that it is difficult to selectively separate scandium because various impurity metals are contained in the starting liquid. be. Further, since the obtained hydroxide is in the form of a gel, the solid-liquid separation treatment such as filtration takes time, and the handleability is poor and the productivity is inferior.
- oxalic acid ((COOH) 2 )
- a method of shu oxidation for example, there is a method as shown in Patent Document 2. That is, scandium is extracted from the scandium-containing solution by solvent extraction, and the back extract is crystallized as scandium oxalate using oxalic acid to separate and purify the scandium.
- an oxidizing agent such as hydrogen peroxide is added to an acidic solution containing scandium or iron as an impurity to control the redox potential (ORP) of the acidic solution within a certain range. While suppressing the precipitation formation of iron (II) oxalate, a oxalic acid solution is added to recover scandium in the form of oxalate oxide.
- an oxidizing agent is added to oxidize the ORP of the acidic solution to about 700 mV with a silver / silver chloride electrode as a reference electrode and maintain the divalent value.
- a method of oxidizing the iron ion of the above to trivalent iron ion is used. Since iron (III) oxalate, which is produced by shu oxidation of trivalent iron ions, has high solubility, it is possible to generate scandium oxalate while preventing the precipitation of iron (II) oxalate. ..
- Patent Document 3 is a method of recovering scandium in the form of high-purity scandium oxide from a solution containing scandium and iron.
- Patent Document 3 discloses a method of adding a scandium-sulfuric acid acidic solution to a oxalic acid solution (hereinafter referred to as "reverse addition method") in order to reduce the amount of oxalic acid added and save the space for industrial equipment. There is.
- the back addition method is carried out by oxalic acid oxidation, the pH of the solution containing scandium and iron is adjusted to the range of ⁇ 0.5 or more and less than 1, and then the pH-adjusted scandium-containing solution is prepared. It is also disclosed to obtain scandium oxalate by adding it to a oxalic acid solution. By doing so, it is possible to prevent the precipitation of iron (II) oxalate without adding an oxidizing agent such as hydrogen peroxide, and further, it is possible to prevent the precipitation of impurities even when the concentration of impurities in the solution is high. ..
- the present invention has been proposed in view of such circumstances, and is obtained in a scandium recovery method including a step of obtaining scandium oxalate by a scandium oxidation treatment from a scandium-containing solution containing an impurity metal element. It is an object of the present invention to provide a method capable of recovering high-purity scandium by effectively reducing the impurity grade of Scandium and suppressing the variation of the impurity grade.
- the present inventor performed the sucrose oxidation treatment by a reverse addition method in which a scandium-containing solution is added to the oxalic acid solution in the sucrose oxidation treatment step, and at that time, the reaction temperature of the sulphate oxidation reaction was specified.
- a scandium-containing solution is added to the oxalic acid solution in the sucrose oxidation treatment step, and at that time, the reaction temperature of the sulphate oxidation reaction was specified.
- the first invention of the present invention is a method for recovering scandium from an acidic solution (scandium-containing solution) containing scandium and an impurity metal element, wherein the scandium is contained in the oxalic acid solution contained in the container. It is a scandium recovery method including a step of obtaining scandium oxalate by performing a scandium oxidation treatment by a reverse addition method of adding a solution, and in the step, the reaction temperature in the oxalate oxidation treatment is set to 20 ° C. or higher and 35 ° C. or lower. ..
- the scandium-containing solution contains at least one selected from the group consisting of iron, nickel, and manganese as the impurity metal element. , Scandium recovery method.
- the third invention of the present invention is the first or second invention, wherein the scandium-containing solution is produced by adding a sulfurizing agent to a leachate obtained by leaching nickel oxide ore with sulfuric acid. This is a method for recovering scandium, which is a solution after separating sulfides.
- the pH of the scandium-containing solution is adjusted to a range of ⁇ 0.5 or more and less than 1.0. This is a scandium recovery method for performing the pH oxidation treatment.
- the fifth invention of the present invention is the method for recovering scandium in any one of the first to fourth inventions, in which an oxidizing agent is not added to the scandium-containing solution to be subjected to the shu oxidation treatment.
- the present invention it is possible to provide a method capable of effectively reducing the impurity grade of the obtained scandium oxalate, suppressing the variation in the impurity grade, and recovering high-purity scandium.
- the flow chart of the shu oxidation treatment is shown. It is a graph when the relationship between the reaction temperature and Ni grade in the oxalic acid treatment in Test Example 1 to Test Example 16 is compared with two kinds of oxalic acid equivalents. It is a graph when the relationship between the reaction temperature and Mn grade in the oxalic acid treatment in Test Example 1 to Test Example 16 is compared with two kinds of oxalic acid equivalents. It is a graph when the relationship between the reaction temperature and Fe grade in the oxalic acid treatment in Test Example 1 to Test Example 16 is compared with two kinds of oxalic acid equivalents.
- the present embodiment a specific embodiment of the present invention (hereinafter, referred to as “the present embodiment”) will be described in detail.
- the present invention is not limited to the following embodiments, and various modifications can be made without changing the gist of the present invention.
- the notation "X to Y" (X and Y are arbitrary numerical values) means "X or more and Y or less”.
- the method for recovering scandium according to the present embodiment is a method for recovering scandium from an acidic solution containing scandium and an impurity metal element (hereinafter, also referred to as "scandium-containing solution").
- this scandium recovery method includes a step of subjecting a scandium-containing solution containing scandium and an impurity metal element to a scandium-containing solution that causes a reaction to oxidize scandium using oxalic acid.
- a scandium-containing solution is added to the oxalic acid solution contained in the container, which is a so-called "reverse addition” method to obtain scandium oxalate. ..
- a scandium-containing solution containing an impurity metal element to be subjected to the shu oxidation treatment a solution obtained by sulphurizing the leachate obtained by high-pressure acid leaching (HPAL) treatment on nickel oxide ore to separate nickel (post-sulfurized liquid).
- HPAL high-pressure acid leaching
- the post-sulfurized liquid may be further subjected to an ion exchange treatment and / or a solvent extraction treatment to separate impurities into a concentrated scandium solution, and the concentrated solution may be used.
- nickel is converted to sulfur by sulfurization treatment, while scandium can remain in the solution, and nickel and scandium can be effectively separated.
- the scandium recovery method according to the present embodiment is characterized in that the reaction temperature is adjusted to a specific range to cause a succulent oxidation reaction in the step of performing the sulphate oxidation treatment by the back addition method.
- the shu oxidation reaction is caused by setting the reaction temperature in the shu oxidation treatment to 20 ° C. or higher and 35 ° C. or lower.
- the impurity metal element contained in the scandium-containing solution can be suppressed from becoming a precipitate as oxalate, and the impurity grade contained in the obtained scandium oxalate crystal can be effectively reduced.
- These scandium-containing solutions contain impurity metal elements such as iron (Fe), manganese (Mn), aluminum (Al), chromium (Cr), and magnesium (Mg).
- impurity metal elements such as iron (Fe), manganese (Mn), aluminum (Al), chromium (Cr), and magnesium (Mg).
- nickel (Ni) that has not been separated as a sulfide may also be contained as an impurity.
- FIG. 1 is a flow chart showing the flow of the hydrometallurgical process of nickel oxide ore.
- the hydrometallurgical process of nickel oxide ore consists of a leaching step S11 in which the nickel oxide ore is leached with sulfuric acid under high temperature and high pressure to obtain a leaching slurry, and a solid-liquid separation step S12 in which the leaching slurry is solid-liquid separated into a leachate and a leachate residue.
- a neutralization step S13 in which a neutralizing agent is added to the leachate to obtain a neutralized starch containing impurities and a post-neutralizing liquid, and a sulfurizing agent is added to the post-neutralizing liquid to obtain nickel sulfide and a post-sulfurized liquid. It has a sulfurization step S14 for obtaining the above.
- Leaching step S11 for example, a high-temperature pressure vessel (autoclave) or the like is used to add sulfuric acid to a slurry of nickel oxide ore and supply high-pressure steam and high-pressure air to a temperature of 240 ° C to 260 ° C. It is a step of performing a stirring treatment below to generate a leaching slurry composed of a leaching solution containing nickel and a leaching residue containing hematite. Scandium is contained in the leachate together with nickel.
- autoclave autoclave
- a stirring treatment below to generate a leaching slurry composed of a leaching solution containing nickel and a leaching residue containing hematite. Scandium is contained in the leachate together with nickel.
- examples of nickel oxide ore mainly include so-called laterite ores such as limonite ore and saprolite ore.
- the nickel content of the laterite ore is usually 0.8 to 2.5% by weight, and is contained as a hydroxide or a siliceous earth (magnesium silicate) mineral.
- these nickel oxide ores contain scandium.
- the leachate slurry is mixed with the cleaning liquid, and then the solid-liquid separation treatment is performed using a solid-liquid separation device such as a thickener. Specifically, the slurry is first diluted with a washing liquid, and then the leaching residue in the slurry is concentrated as a thickener sediment. Thereby, the nickel content adhering to the leachate residue can be reduced according to the degree of dilution thereof. In actual operation, thickeners with such functions are used in multiple stages.
- the neutralization step S13 is a step of adding a neutralizing agent to the leachate to adjust the pH to obtain a neutralized starch containing an impurity element and a neutralized liquid.
- a neutralizing agent such as nickel, cobalt, and scandium are contained in the liquid after neutralization, and most of the impurities such as aluminum become neutralized starch.
- a known neutralizing agent can be used, and examples thereof include limestone, slaked lime, and sodium hydroxide. Further, in the neutralization treatment, it is preferable to adjust the pH to the range of 1 to 4 while suppressing the oxidation of the separated leachate, and it is more preferable to adjust the pH to the range of 1.5 to 2.5. preferable. If the pH is less than 1, neutralization may be insufficient and the neutralized starch and the neutralized liquid may not be separated. On the other hand, when the pH exceeds 4, not only impurities such as aluminum but also valuable metals such as scandium and nickel may be contained in the neutralized starch.
- the sulfurization step S14 is a step of adding a sulfurizing agent to the neutralized liquid obtained in the neutralization step S13 to obtain nickel sulfide and a post-sulfurized liquid.
- nickel, cobalt, zinc and the like are recovered as sulfurized substances, and scandium and the like remain in the after sulfidation liquid. Therefore, nickel and scandium can be effectively separated by the sulfurization treatment in such a hydrometallurgical process.
- a sulfurizing agent such as hydrogen sulfide gas, sodium sulfide, and sodium hydride sulfide is supplied to the obtained after-neutralization liquid to provide a sulfide containing nickel having a small impurity component (sulfide).
- Nickel sulfide) and a post-sulfurization liquid containing scandium and the like are produced by stabilizing the nickel concentration at a low level.
- the nickel sulfide slurry is separated and separated using a sedimentation separator such as a thickener, and the nickel sulfide is separated and recovered from the bottom of the thickener, while the after-sulfurization liquid, which is an aqueous solution component, overflows. Let me collect it.
- a sedimentation separator such as a thickener
- the post-sulfidation solution which is an acidic sulfuric acid solution obtained through each step in the hydrometallurgical process of nickel oxide ore as described above, is recovered and used as a starting material.
- the scandium recovery method produces scandium oxide from such a solution.
- the ion exchange treatment and the solvent extraction treatment will be described respectively.
- the solvent extraction treatment is described by taking as an example a mode in which the eluent obtained through the ion exchange treatment is treated, it is possible to perform only the solvent extraction treatment without performing the ion exchange treatment. good.
- the post-sulfidation liquid contains aluminum, chromium and the like as impurities. For this reason, when recovering scandium in the solution as scandium oxide, it is preferable to remove these impurities and concentrate the scandium.
- Examples of the method for concentrating scandium include a method by ion exchange treatment using a chelate resin.
- FIG. 2 is a flow chart showing an example of the flow of an ion exchange process performed by an ion exchange reaction using a chelate resin.
- FIG. 2 also shows the flow until the scandium eluent obtained by the ion exchange treatment is subjected to the solvent extraction treatment.
- the post-sulfurization liquid obtained through the sulfurization step S14 (FIG. 1) in the hydrometallurgical process of nickel oxide ore is brought into contact with the chelate resin, and the scandium in the post-sulfurization liquid is adsorbed on the chelate resin.
- the scandium (Sc) eluent is obtained.
- the mode (each step) of the ion exchange treatment is not particularly limited, but as shown in FIG. 2, for example, an adsorption step S21 in which the post-sulfurized liquid is brought into contact with the chelate resin to adsorb scandium to the chelate resin, and sulfuric acid is added to the chelate resin.
- the aluminum removal step S22 for removing the aluminum adsorbed on the chelate resin by contacting the chelate resin
- the scandium elution step S23 for obtaining the scandium eluent by contacting sulfuric acid with the chelate resin that has undergone the aluminum removal step S22, and the scandium elution step S23.
- An example thereof includes a chrome removing step S24 in which sulfuric acid is brought into contact with the chelate resin and the chrome adsorbed on the chelate resin is removed in the adsorption step S21.
- the post-sulfurized liquid is brought into contact with the chelate resin to adsorb scandium to the chelate resin.
- the type of chelate resin is not particularly limited, and for example, a resin having iminodiacetic acid as a functional group can be used.
- Al removal step S22 sulfuric acid of 0.1 N or less is brought into contact with the chelate resin adsorbed with scandium in the adsorption step S21 to remove the aluminum adsorbed on the chelate resin.
- [Scandium elution process] sulfuric acid of 0.3N or more and less than 3N is brought into contact with the chelate resin that has undergone the aluminum removal step S22 to obtain a scandium eluent.
- the normality of sulfuric acid used in the eluent is preferably maintained in the range of 0.3N or more and less than 3N, and more preferably maintained in the range of 0.5N or more and less than 2N.
- chromium removal process In the chromium removing step S24, sulfuric acid of 3N or more is brought into contact with the chelate resin that has undergone the scandium elution step S23 to remove chromium adsorbed on the chelate resin.
- sulfuric acid of 3N or more When the normality of sulfuric acid used in the eluent is less than 3N when removing chromium, it is not preferable because chromium is not properly removed from the chelate resin.
- the concentration of the scandium eluent can be increased.
- the concentration of recovered scandium increases as the number of repetitions increases, but the degree of increase in the concentration of recovered scandium decreases even if the number of repetitions is too large, so it is industrially about 8 times or less. preferable.
- the extractant used for solvent extraction is not particularly limited, and an amine-based extractant, a phosphoric acid-based extractant, or the like can be used. Further, depending on the type of the extractant, the scandium to be extracted can be extracted in an organic solvent containing the extractant, or the extractant can selectively extract the impurity component and the scandium is contained in the extraction residue. It can be made to remain. For example, when an amine-based extractant is used, since it is an extractant having low selectivity with scandium, impurity components are selectively extracted in an organic solvent, and scandium is concentrated in the extraction residue.
- the mode (each step) of the solvent extraction treatment is not particularly limited, but the extraction step S31 and the extraction step S31 in which the scandium eluent and the extractant are mixed to extract impurities and then separated into an organic solvent and a drawing residue containing scandium.
- the scrubbing step S32 in which a hydrochloric acid solution or a sulfuric acid solution is mixed with the organic solvent after extraction to separate a trace amount of scandium contained in the organic solvent after extraction, and the back extraction starting solution is mixed with the organic solvent after washing, and the organic solvent is used after washing.
- An example thereof includes a back extraction step S33 in which impurities are back-extracted to obtain a back-extract solution.
- extraction process In the extraction step S31, a scandium-containing solution and an organic solvent containing an extractant are mixed, impurities are selectively extracted into the organic solvent, and the organic solvent containing the impurities and the scandium-concentrated extract residue liquid. And get.
- an amine-based extractant for example, an amine-based extractant is used.
- the amine-based extractant products such as PrimeneJM-T, which is a primary amine, LA-1, which is a secondary amine, TNOA (Tri-n-octylamine), which is a tertiary amine, and TIOA (Tri-i-octylamine).
- An amine-based extractant known by the name can be used.
- an extractant such as an amine-based extractant with a hydrocarbon-based organic solvent or the like before use.
- concentration of the extractant in the organic solvent is not particularly limited, but is preferably about 1% by volume or more and 10% by volume or less, particularly 5 volumes, in consideration of phase separation during extraction and back extraction described later. It is more preferably about%.
- the volume ratio of the organic solvent to the scandium-containing solution at the time of extraction is not particularly limited, but the amount of the organic solvent mol is about 0.01 times or more and 0.1 times or less with respect to the amount of metal in the scandium-containing solution. Is preferable.
- a sulfuric acid solution As the solution (washing solution) used for scrubbing, a sulfuric acid solution, a hydrochloric acid solution, or the like can be used. Further, it is also possible to use water to which soluble chloride or sulfate is added. Specifically, when a sulfuric acid solution is used as the cleaning solution, it is preferable to use a solution having a concentration range of 1.0 mol / L or more and 3.0 mol / L or less.
- back extraction step S33 impurities are back extracted from the organic solvent from which the impurities have been extracted in the extraction step S31. Specifically, in the back extraction step S33, a back extraction solution (back extraction starting solution) is added to an organic solvent containing an extractant and mixed to cause a reaction opposite to the extraction process in the extraction step S31. The impurities are back-extracted to obtain a liquid after back-extraction containing the impurities.
- a back extraction solution back extraction starting solution
- the concentration of the solution containing carbonate, which is a back-extraction solution is preferably about 0.5 mol / L or more and 2 mol / L or less from the viewpoint of suppressing excessive use.
- the back-extraction treatment is similarly performed by adding the back-extraction solution to the scrubbing extractant and mixing it. It can be performed.
- the extractant after adding a carbonate solution such as sodium carbonate to the extractant after extraction or the extractant after scrubbing in this way and performing a back-extraction treatment to separate impurities is again in the extraction step S31. It can be repeatedly used as an extractant used in the extraction process.
- the scandium recovery method includes a step of subjecting a scandium-containing solution to an oxalate treatment to convert scandium into an oxalate (scandium oxalate).
- a scandium-containing solution which is a back extract obtained through the above-mentioned solvent extraction treatment, is used to perform a scandium oxidation treatment for forming scandium oxalate crystals.
- the scandium-containing solution obtained through the solvent extraction treatment is a solution in which most of the impurity metal elements have been removed by the above-mentioned ion exchange treatment and the solvent extraction treatment to concentrate the scandium. However, it contains a certain amount of impurity metal elements that were not removed by these treatments (see the composition of the Shu oxidation starting solution shown in Table 1 in Examples described later).
- the impurity metal element include at least iron, nickel, manganese, aluminum, chromium, magnesium and the like.
- the so-called "reverse addition” method is used as the method of shu oxidation treatment. Specifically, the scandium-containing solution is gradually added to the oxalic acid solution contained in a predetermined container to precipitate and generate solid crystals of scandium oxalate.
- iron shu oxidation which is an impurity metal element, is performed without adding an oxidizing agent such as hydrogen peroxide to adjust the redox potential (ORP). Can be suppressed and the formation of iron (II) oxalate precipitates can be prevented.
- the reaction temperature is set to a specific range, specifically, 20 ° C. or higher and 35 ° C. or lower in the shu oxidation treatment by the reverse addition method. Further, it is preferably 20 ° C. or higher and 30 ° C. or lower, and more preferably 23 ° C. or higher and 30 ° C. or lower.
- metal elements other than scandium which is a rare earth element
- oxalic acid reacts with oxalic acid to form a complex
- impurity metal elements with low complex stability are adsorbed on the precipitate of scandium oxalate and co-precipitate. .. It is considered that the stability of such a complex depends not only on the type of the metal element but also on the conditions of the oxalic acid treatment, which causes variations in the impurity grade in the obtained scandium oxalate.
- a scandium-containing solution is added to the oxalic acid solution contained in a predetermined container to cause a oxalic acid reaction, and the oxalic acid treatment is carried out by a "reverse addition" method.
- the reaction temperature at this time is set to 20 ° C. or higher and 35 ° C. or lower.
- scandium oxalate containing scandium with high purity and stable impurity-containing specifications can be obtained, and by roasting the scandium oxalate, high quality can be obtained.
- Scandium oxide can be obtained.
- FIG. 3 shows a flow chart of the shu oxidation treatment.
- the reaction temperature is set to 20 ° C. or higher and 35 ° C. or lower during the oxalate oxidation treatment by the back addition method.
- the temperature adjusting step S41 for adjusting the temperature of the scandium-containing solution and the temperature-adjusted solution starting solution for oxalic acid
- the crystallization step S42 for precipitating The obtained scandium oxalate crystals can be recovered by passing through the filtration / cleaning step S43 in which the filtration / cleaning treatment is performed.
- the pH of the scandium-containing solution may be adjusted before or after the temperature adjustment step S41, or may be performed at the same timing as the temperature adjustment.
- the temperature of the scandium-containing solution to be subjected to the shu oxidation treatment is adjusted to 20 ° C. or higher and 35 ° C. or lower, preferably 20 ° C. or higher and 30 ° C. or lower, and more preferably 23 ° C. or higher and 30 ° C. or lower.
- the temperature of the scandium-containing solution is adjusted to a range of 20 ° C. or higher and 35 ° C. or lower, and the temperature is maintained to cause a reaction in the next crystallization step S42 to obtain scandium oxalate crystals. It is possible to reduce the contained impurity grade and suppress the variation in the impurity grade.
- the temperature adjusting method for the scandium-containing solution is not particularly limited, and can be adjusted by using, for example, a heater or the like.
- the oxalic acid solution used for the oxalic acid treatment is previously prepared. It is preferable to adjust the temperature to a range of 20 ° C. or higher and 35 ° C. or lower, and maintain the temperature for reaction. Thereby, the reaction temperature can be appropriately maintained in the range of 20 ° C. or higher and 35 ° C. or lower, and the variation in the impurity grade in the obtained scandium oxalate can be more effectively suppressed.
- the reaction temperature is set to 20 ° C. or higher and 35 ° C. or lower, and a scandium-containing solution (starting solution for oxalic acid) is added to the oxalic acid solution to perform a oxalic acid treatment to cause a reaction to oxidize scandium.
- a scandium-containing solution starting solution for oxalic acid
- the reaction temperature of the oxalate oxidation reaction if the reaction temperature is higher than 35 ° C., the impurities grade in the obtained scandium oxalate varies. Further, if the reaction temperature is less than 20 ° C., the reaction rate may decrease, and the solubility of the oxalate may decrease, causing a problem that the oxalate precipitates in an unfavorable place such as a supply pipe.
- the oxalic acid solution is contained in the reaction vessel, and the scandium-containing solution is added to the oxalic acid solution to cause a reaction by the "reverse addition" method.
- the amount of the oxalic acid solution is preferably at least 1.05 times or more, more preferably 2.0 times or more the equivalent amount required for precipitating scandium in the scandium-containing solution as an oxalate. preferable. If the amount used is less than 1.05 times the required equivalent, it may not be possible to effectively recover the entire amount of scandium.
- the oxalic acid solution it is preferable to use a solution whose pH is adjusted to the range of -0.5 or more and 1.0 or less.
- the pH of the oxalic acid solution can also be adjusted to further reduce the impurity grade, resulting in a high pH. Pure scandium can be recovered.
- the scandium-containing solution is adjusted to a temperature of 20 ° C. or higher and 35 ° C. or lower in advance, and the reaction temperature in the crystallization step S42 is set to 20 ° C. or higher and 35 ° C. or lower while maintaining the temperature.
- the reaction temperature when the scandium-containing solution is added to the oxalic acid solution to cause a reaction may be maintained in the range of 20 ° C. or higher and 35 ° C. or lower.
- scandium oxide is obtained by roasting the crystals of scandium oxalate obtained by performing the oxalate oxidation treatment as described above.
- the roasting treatment is a treatment in which the scandium oxalate crystals obtained by the oxalate oxidation treatment are washed with water, dried, and then roasted. By undergoing this roasting treatment, scandium can be recovered as scandium oxide.
- the reaction is caused by setting the reaction temperature in the above-mentioned oxalic acid oxidation treatment within a specific range, the impurity grade of the scandium oxalate to be produced is effectively reduced, and the impurity grade is reduced. Variations are also suppressed. Therefore, by roasting such scandium oxalate, it is possible to obtain scandium oxide containing high-purity scandium in which the impurity grade is reduced and the variation in the impurity grade is suppressed.
- the conditions of the roasting treatment are not particularly limited, but for example, it may be placed in a tube furnace and heated at about 900 ° C. for about 2 hours. Industrially, it is preferable to use a continuous furnace such as a rotary kiln because drying and roasting can be performed by the same apparatus.
- Nickel oxide ore was leached with sulfuric acid using an autoclave, and slaked lime was added to the obtained leachate to neutralize it. Then, a sulfurizing agent was added to the obtained neutralized liquid to cause a sulfurization reaction, and nickel, cobalt and the like were separated as sulfides to obtain a scandium-containing post-sulfurized liquid.
- Scandium oxidation starting solution was prepared. 500 ml of Shu oxidation starting solution was prepared for each test under the conditions shown in Tables 1 and 2 below. The pH was adjusted under the same temperature conditions as the reaction temperature (reaction temperature) of each test.
- the redox potential (ORP) of the scandium-containing solution was 500 mV to 560 mV with a silver / silver chloride electrode as a standard electrode.
- oxalic acid solution used for the oxalic acid treatment a solution in which 100 g of oxalic acid was dissolved per 1 L of the liquid volume was prepared.
- a oxalic acid solution in an amount of 183 ml, which is 2.7 equivalents, or 344 ml, which is 5.1 equivalents, with respect to scandium contained in the scandium used in each test is contained in a container.
- An initial solution of shu oxidation (scandium-containing solution) was added to the oxalic acid solution at a flow rate of 2.3 ml / min and reacted.
- the temperature (reaction temperature) at the time of the reaction is set at room temperature (23 ° C.), 30 ° C., 35 ° C., 42 ° C., or 50 ° C. for each test, and the oxalic acid solution is used as the starting solution for oxalic acid.
- the temperature was maintained from the start of addition to the end of stirring for 1 hour.
- Table 1 shows the test conditions for the equivalent of the oxalic acid solution and the reaction temperature in each test, and the analysis results of the concentration of the metal component contained in the scandium-containing solution (starting solution of oxalic acid) used for the oxalic acid treatment. As shown in Table 1, it can be seen that the scandium-containing solution contains various impurity metal elements.
- the whole amount was filtered using a suction filtration device and a membrane filter having a pore size of 0.45 ⁇ m, and scandium oxalate crystals were separated. Further, the separated crystals were put into 140 ml of pure water so as to have a slurry concentration of about 50 g / L, and repulp washing was repeated twice.
- the whole amount was filtered using the same suction filtration device and membrane filter, and scandium oxalate crystals were recovered. Then, the obtained scandium oxalate crystals were dried overnight in an air dryer at a temperature of 105 ° C., and the dried crystals were analyzed by the ICP atomic absorption spectrophotometric method to confirm the impurity grade.
- Table 2 below shows the analysis results of the impurity grade of scandium oxalate obtained in Test Examples 1 to 16.
- Test Examples 11 to 16 in which the reaction temperature was higher than 35 ° C.
- the reaction temperature was higher than 35 ° C.
- Test Examples 11 to 16 not only the effect of reducing the impurity grade was inferior, but also the impurity grade varied due to the difference in the oxalic acid equivalent conditions under the same reaction temperature conditions.
- FIGS. 4 to 6 show two types (2.) of the relationship between the Ni grade (FIG. 4), the Mn grade (FIG. 5), the Fe grade (FIG. 6) and the reaction temperature, respectively, based on Table 3 below. It is a graph figure when comparing with the oxalic acid equivalent of 7 equivalents, 5.1 equivalents).
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Abstract
Provided is a method for recovering high-purity scandium by effectively reducing impurity content of obtained scandium oxalate and reducing variation in impurity content. The present invention is a method that is for recovering scandium from an acidic solution (scandium-containing solution) containing scandium and impurity metal elements, and that comprises a step for performing obtaining scandium oxalate by performing an oxalation treatment by inverse addition in which a scandium-containing solution is added to an oxalic acid solution contained in a container. In the step, the reaction temperature in the oxalation treatment is 20-35°C.
Description
本発明は、スカンジウムの回収方法に関する。より詳しくは、不純物を含んだ硫酸酸性溶液からスカンジウムを選択的に回収するスカンジウムの回収方法に関する。
The present invention relates to a method for recovering scandium. More specifically, the present invention relates to a method for recovering scandium, which selectively recovers scandium from an acidic sulfuric acid solution containing impurities.
スカンジウムは、アルミニウム合金の添加元素としたり、燃料電池の電解質として極めて有用であることが知られている。しかしながら、従来から生産量が少なく、高価であるため、広く用いられるには至っていなかった。
Scandium is known to be extremely useful as an additive element for aluminum alloys and as an electrolyte for fuel cells. However, it has not been widely used because of its low production volume and high cost.
スカンジウムは、希土類元素の中でも特にイオン半径が小さく、通常の希土類鉱物中には殆ど存在しない。その代わり、アルミニウム、スズ、タングステン、ジルコニウム、鉄、ニッケル等の酸化鉱中に広く、微量に存在していることが知られている。
Scandium has a particularly small ionic radius among rare earth elements, and is rarely present in ordinary rare earth minerals. Instead, it is known to be widely present in trace amounts in oxide ores of aluminum, tin, tungsten, zirconium, iron, nickel and the like.
近年、ニッケル酸化鉱石を硫酸と共に加圧容器に装入し、高温に加熱してニッケルを含有する浸出液と浸出残渣とに固液分離するＨＰＡＬプロセスが実用化されてきた。ＨＰＡＬプロセスで得られた浸出液に中和剤を添加して不純物を分離し、さらに硫化剤を添加してニッケルをニッケル硫化物として回収する。そして、回収したニッケル硫化物を既存のニッケル製錬工程で処理することで、電気ニッケルや硫酸ニッケル、塩化ニッケル等のニッケル塩化合物を得ることができる。
In recent years, the HPAL process has been put into practical use, in which nickel oxide ore is charged into a pressure vessel together with sulfuric acid and heated to a high temperature to solid-liquid separation into a nickel-containing leachate and a leachate residue. A neutralizing agent is added to the leachate obtained by the HPAL process to separate impurities, and a sulfurizing agent is further added to recover nickel as nickel sulfide. Then, by treating the recovered nickel sulfide in an existing nickel smelting process, nickel salt compounds such as electric nickel, nickel sulfate, and nickel chloride can be obtained.
上記のようなＨＰＡＬプロセスを用いる場合、ニッケル酸化鉱石に含まれるスカンジウムは、例えば特許文献１に示されるように、ニッケルと共に浸出されて浸出液に含まれる。そして、浸出液に中和剤を添加して不純物を分離し、次いで硫化剤を添加すると、ニッケルはニッケル硫化物として回収され、スカンジウムは硫化物を形成せずに硫化剤添加後の酸性溶液（硫酸酸性溶液）に含まれる。このように、ＨＰＡＬプロセスを使用することで、ニッケルとスカンジウムとを効果的に分離できることも知られている。
When the HPAL process as described above is used, the scandium contained in the nickel oxide ore is leached together with nickel and contained in the leachate, for example, as shown in Patent Document 1. Then, when a neutralizing agent is added to the leachate to separate impurities and then a sulfide agent is added, nickel is recovered as nickel sulfide, and scandium does not form sulfide and is an acidic solution after addition of the sulfide agent (sulfuric acid). Included in acidic solution). Thus, it is also known that nickel and scandium can be effectively separated by using the HPAL process.
しかしながら、硫酸酸性溶液中のスカンジウム濃度は希薄（数十ｍｇ／Ｌ）であり、その他の、特に鉄やアルミニウム等の不純物の方がはるかに多く含まれる。
However, the scandium concentration in the sulfuric acid acidic solution is dilute (several tens of mg / L), and other impurities such as iron and aluminum are contained in a much larger amount.
そこで、スカンジウムを濃縮し精製するために、イオン交換樹脂を用いた吸着法や溶媒抽出法によって選択的にスカンジウムを回収、濃縮する方法が用いられる。その後、さらにスカンジウム品位を向上させるために、濃縮されたスカンジウム溶液に対してアルカリを添加し晶析反応を生じさせることで水酸化物を形成させたり、シュウ酸を添加してシュウ酸化物を晶析させる等の処理を行うことで、回収している。
Therefore, in order to concentrate and purify scandium, a method of selectively recovering and concentrating scandium by an adsorption method using an ion exchange resin or a solvent extraction method is used. After that, in order to further improve the scandium quality, an alkali is added to the concentrated scandium solution to cause a crystallization reaction to form a hydroxide, or oxalic acid is added to crystallize the oxalic acid. It is recovered by processing such as analysis.
例えば、上述した方法の中で、スカンジウムを水酸化物として晶析させる方法については、始液中に様々な不純物金属が含まれているため、選択的にスカンジウムを分離することが難しいという問題がある。また、得られる水酸化物がゲル状であるため、濾過等の固液分離処理に時間が掛かる等、ハンドリング性が悪く生産性が劣る。
For example, among the above-mentioned methods, the method of crystallizing scandium as a hydroxide has a problem that it is difficult to selectively separate scandium because various impurity metals are contained in the starting liquid. be. Further, since the obtained hydroxide is in the form of a gel, the solid-liquid separation treatment such as filtration takes time, and the handleability is poor and the productivity is inferior.
そこで、スカンジウムを選択的に回収する方法として、上述したように、シュウ酸（（ＣＯＯＨ）２）を用いた晶析反応（以下、「シュウ酸化」と称する）が多く用いられる。
Therefore, as a method for selectively recovering scandium, as described above, a crystallization reaction using oxalic acid ((COOH) 2 ) (hereinafter referred to as “oxalic acid”) is often used.
シュウ酸化の方法としては、例えば特許文献２に示すような方法がある。すなわち、スカンジウム含有溶液から溶媒抽出によってスカンジウムを抽出し、逆抽出液からシュウ酸を用いてシュウ酸スカンジウムとして結晶化してスカンジウムを分離精製する。シュウ酸化の処理については、具体的には、スカンジウムや不純物としての鉄を含む酸性溶液に過酸化水素等の酸化剤を添加して酸性溶液の酸化還元電位（ＯＲＰ）を一定範囲に制御し、シュウ酸化鉄（II）の沈澱生成を抑制しながら、シュウ酸溶液を添加してスカンジウムをシュウ酸化物の形態で回収する。
As a method of shu oxidation, for example, there is a method as shown in Patent Document 2. That is, scandium is extracted from the scandium-containing solution by solvent extraction, and the back extract is crystallized as scandium oxalate using oxalic acid to separate and purify the scandium. Regarding the treatment of shu oxidation, specifically, an oxidizing agent such as hydrogen peroxide is added to an acidic solution containing scandium or iron as an impurity to control the redox potential (ORP) of the acidic solution within a certain range. While suppressing the precipitation formation of iron (II) oxalate, a oxalic acid solution is added to recover scandium in the form of oxalate oxide.
上述した処理において、スカンジウムや鉄を含む酸性溶液には、多くが２価イオンの形態の鉄が含まれており、そのままシュウ酸化を行った場合には、生成するシュウ酸化鉄（II）の溶解度が小さい（水への溶解度：０．０２２ｇ／１００ｇ）ことにより、シュウ酸反応によってシュウ酸鉄（II）の沈澱が生じてしまう。
In the above-mentioned treatment, most of the acidic solutions containing scandium and iron contain iron in the form of divalent ions, and when iron oxide is carried out as it is, the solubility of iron (II) oxide produced. Due to its small size (solubility in water: 0.022 g / 100 g), iron (II) oxalate precipitates due to the oxalic acid reaction.
そこで、シュウ酸鉄（II）の沈澱を防止するために、酸化剤を添加して酸性溶液のＯＲＰを銀／塩化銀電極を参照電極とする値で７００ｍＶ程度に酸化して維持し、２価の鉄イオンを３価の鉄イオンに酸化させる方法が用いられる。３価の鉄イオンがシュウ酸化されて生成するシュウ酸化鉄（III）は、溶解度が高いことから、シュウ酸鉄（II）の沈澱を防止しながら、スカンジウムのシュウ酸化物を生成させることができる。
Therefore, in order to prevent the precipitation of iron (II) oxalate, an oxidizing agent is added to oxidize the ORP of the acidic solution to about 700 mV with a silver / silver chloride electrode as a reference electrode and maintain the divalent value. A method of oxidizing the iron ion of the above to trivalent iron ion is used. Since iron (III) oxalate, which is produced by shu oxidation of trivalent iron ions, has high solubility, it is possible to generate scandium oxalate while preventing the precipitation of iron (II) oxalate. ..
また、シュウ酸化工程における更なる方法として、例えば特許文献３には、スカンジウムと鉄とを含んだ溶液から高純度の酸化スカンジウムの形態でスカンジウムを回収する方法である。特許文献３には、シュウ酸添加量の削減や工業設備スペースの節約のために、シュウ酸溶液中にスカンジウム硫酸酸性溶液を添加する手法（以下、「逆添加法」と称する）が開示されている。
Further, as a further method in the shu oxidation step, for example, Patent Document 3 is a method of recovering scandium in the form of high-purity scandium oxide from a solution containing scandium and iron. Patent Document 3 discloses a method of adding a scandium-sulfuric acid acidic solution to a oxalic acid solution (hereinafter referred to as "reverse addition method") in order to reduce the amount of oxalic acid added and save the space for industrial equipment. There is.
この特許文献３では、シュウ酸化で逆添加法を行うとともに、スカンジウムと鉄とを含有する溶液のｐＨを－０．５以上１未満の範囲に調整し、次いで、ｐＨ調整後のスカンジウム含有溶液をシュウ酸溶液の中に添加してシュウ酸スカンジウムを得ることも開示されている。このようにすることで、過酸化水素等の酸化剤を添加しなくとも、シュウ酸鉄（II）の沈澱生成を防止でき、さらに、溶液中の不純物濃度が高い場合でも不純物の沈澱を防止できる。
In this Patent Document 3, the back addition method is carried out by oxalic acid oxidation, the pH of the solution containing scandium and iron is adjusted to the range of −0.5 or more and less than 1, and then the pH-adjusted scandium-containing solution is prepared. It is also disclosed to obtain scandium oxalate by adding it to a oxalic acid solution. By doing so, it is possible to prevent the precipitation of iron (II) oxalate without adding an oxidizing agent such as hydrogen peroxide, and further, it is possible to prevent the precipitation of impurities even when the concentration of impurities in the solution is high. ..
しかしながら、逆添加法によるシュウ酸化を行った際の回収物においては、品位のばらつきが発生することがあり、不純物の品位上昇や最終品位のスペックアウトが生じるという問題がある。
However, there is a problem that the quality of the recovered product obtained by the reverse addition method may vary, resulting in an increase in the quality of impurities and a spec-out of the final quality.
本発明は、このような実情に鑑みて提案されたものであり、不純物金属元素を含むスカンジウム含有溶液からシュウ酸化処理によってシュウ酸化スカンジウムを得る工程を含むスカンジウムの回収方法において、得られるシュウ酸化スカンジウムの不純物品位を効果的に低減し、またその不純物品位のばらつきを抑えて、高純度なスカンジウムを回収することを可能にする方法を提供することを目的とする。
The present invention has been proposed in view of such circumstances, and is obtained in a scandium recovery method including a step of obtaining scandium oxalate by a scandium oxidation treatment from a scandium-containing solution containing an impurity metal element. It is an object of the present invention to provide a method capable of recovering high-purity scandium by effectively reducing the impurity grade of Scandium and suppressing the variation of the impurity grade.
本発明者は、鋭意検討を重ねた結果、シュウ酸化処理の工程において、シュウ酸溶液にスカンジウム含有溶液を添加する逆添加法によりシュウ酸化処理を行い、そのとき、シュウ酸化反応の反応温度を特定の範囲に調整し維持することで、上述した課題を解決できることを見出し、本発明を完成するに至った。
As a result of repeated diligent studies, the present inventor performed the sucrose oxidation treatment by a reverse addition method in which a scandium-containing solution is added to the oxalic acid solution in the sucrose oxidation treatment step, and at that time, the reaction temperature of the sulphate oxidation reaction was specified. We have found that the above-mentioned problems can be solved by adjusting and maintaining the above range, and have completed the present invention.
（１）本発明の第１の発明は、スカンジウムと、不純物金属元素とを含有する酸性溶液（スカンジウム含有溶液）からスカンジウムを回収する方法であって、容器に収容したシュウ酸溶液に前記スカンジウム含有溶液を添加する逆添加法によりシュウ酸化処理を行い、シュウ酸スカンジウムを得る工程を含み、前記工程では、前記シュウ酸化処理における反応温度を２０℃以上３５℃以下とする、スカンジウムの回収方法である。
(1) The first invention of the present invention is a method for recovering scandium from an acidic solution (scandium-containing solution) containing scandium and an impurity metal element, wherein the scandium is contained in the oxalic acid solution contained in the container. It is a scandium recovery method including a step of obtaining scandium oxalate by performing a scandium oxidation treatment by a reverse addition method of adding a solution, and in the step, the reaction temperature in the oxalate oxidation treatment is set to 20 ° C. or higher and 35 ° C. or lower. ..
（２）本発明の第２の発明は、第１の発明において、前記スカンジウム含有溶液は、前記不純物金属元素として、少なくとも、鉄、ニッケル、及びマンガンからなる群から選ばれる１種以上を含有する、スカンジウムの回収方法である。
(2) In the second invention of the present invention, in the first invention, the scandium-containing solution contains at least one selected from the group consisting of iron, nickel, and manganese as the impurity metal element. , Scandium recovery method.
（３）本発明の第３の発明は、第１又は第２の発明おいて、前記スカンジウム含有溶液は、ニッケル酸化鉱石を硫酸により浸出して得られた浸出液に硫化剤を添加して生成する硫化物を分離した後の溶液である、スカンジウムの回収方法である。
(3) The third invention of the present invention is the first or second invention, wherein the scandium-containing solution is produced by adding a sulfurizing agent to a leachate obtained by leaching nickel oxide ore with sulfuric acid. This is a method for recovering scandium, which is a solution after separating sulfides.
（４）本発明の第４の発明は、第１乃至第３のいずれかの発明において、前記工程では、前記スカンジウム含有溶液のｐＨを－０．５以上１．０未満の範囲に調整して前記シュウ酸化処理を行う、スカンジウムの回収方法である。
(4) In the fourth aspect of the present invention, in any one of the first to third inventions, in the step, the pH of the scandium-containing solution is adjusted to a range of −0.5 or more and less than 1.0. This is a scandium recovery method for performing the pH oxidation treatment.
（５）本発明の第５の発明は、第１乃至第４のいずれかの発明において、前記シュウ酸化処理に供する前記スカンジウム含有溶液には、酸化剤を添加しない、スカンジウムの回収方法である。
(5) The fifth invention of the present invention is the method for recovering scandium in any one of the first to fourth inventions, in which an oxidizing agent is not added to the scandium-containing solution to be subjected to the shu oxidation treatment.
本発明によれば、得られるシュウ酸化スカンジウムの不純物品位を有効に低減し、またその不純物品位のばらつきを抑えて、高純度なスカンジウムを回収することを可能にする方法を提供することができる。
According to the present invention, it is possible to provide a method capable of effectively reducing the impurity grade of the obtained scandium oxalate, suppressing the variation in the impurity grade, and recovering high-purity scandium.
以下、本発明の具体的な実施形態（以下、「本実施の形態」という）について詳細に説明する。なお、本発明は以下の実施形態に限定されず、本発明の要旨を変更しない範囲で種々の変更が可能である。また、本明細書において、「Ｘ～Ｙ」（Ｘ、Ｙは任意な数値）との表記は、「Ｘ以上Ｙ以下」の意味である。
Hereinafter, a specific embodiment of the present invention (hereinafter, referred to as “the present embodiment”) will be described in detail. The present invention is not limited to the following embodiments, and various modifications can be made without changing the gist of the present invention. Further, in the present specification, the notation "X to Y" (X and Y are arbitrary numerical values) means "X or more and Y or less".
≪１．概要≫
本実施の形態に係るスカンジウムの回収方法は、スカンジウムと、不純物金属元素とを含有する酸性溶液（以下、「スカンジウム含有溶液」ともいう）からスカンジウムを回収する方法である。 ≪1. Overview ≫
The method for recovering scandium according to the present embodiment is a method for recovering scandium from an acidic solution containing scandium and an impurity metal element (hereinafter, also referred to as "scandium-containing solution").
本実施の形態に係るスカンジウムの回収方法は、スカンジウムと、不純物金属元素とを含有する酸性溶液（以下、「スカンジウム含有溶液」ともいう）からスカンジウムを回収する方法である。 ≪1. Overview ≫
The method for recovering scandium according to the present embodiment is a method for recovering scandium from an acidic solution containing scandium and an impurity metal element (hereinafter, also referred to as "scandium-containing solution").
具体的に、このスカンジウムの回収方法は、スカンジウムと不純物金属元素とを含むスカンジウム含有溶液に対し、シュウ酸を用いてスカンジウムをシュウ酸化する反応を生じさせるシュウ酸化処理を施す工程を含む。特に、本実施の形態に係るスカンジウムの回収方法では、シュウ酸化処理として、容器に収容したシュウ酸溶液にスカンジウム含有溶液を添加する、いわゆる「逆添加」法により処理を行ってシュウ酸スカンジウムを得る。
Specifically, this scandium recovery method includes a step of subjecting a scandium-containing solution containing scandium and an impurity metal element to a scandium-containing solution that causes a reaction to oxidize scandium using oxalic acid. In particular, in the scandium recovery method according to the present embodiment, as the oxalic acid treatment, a scandium-containing solution is added to the oxalic acid solution contained in the container, which is a so-called "reverse addition" method to obtain scandium oxalate. ..
シュウ酸化処理に供する、不純物金属元素を含むスカンジウム含有溶液としては、ニッケル酸化鉱石に対する高圧酸浸出（ＨＰＡＬ）処理により得られた浸出液を硫化処理してニッケルを分離した後の溶液（硫化後液）を用いることができる。また、硫化後液に対してさらにイオン交換処理及び／又は溶媒抽出処理を施すことで不純物を分離してスカンジウムを濃縮させた溶液とし、その濃縮後の溶液を用いることもできる。なお、ＨＰＡＬプロセスでは、硫化処理によりニッケルを硫化物とする一方で、スカンジウムは溶液中に残留させることができ、ニッケルとスカンジウムを効果的に分離することができる。
As a scandium-containing solution containing an impurity metal element to be subjected to the shu oxidation treatment, a solution obtained by sulphurizing the leachate obtained by high-pressure acid leaching (HPAL) treatment on nickel oxide ore to separate nickel (post-sulfurized liquid). Can be used. Further, the post-sulfurized liquid may be further subjected to an ion exchange treatment and / or a solvent extraction treatment to separate impurities into a concentrated scandium solution, and the concentrated solution may be used. In the HPAL process, nickel is converted to sulfur by sulfurization treatment, while scandium can remain in the solution, and nickel and scandium can be effectively separated.
そして、本実施の形態に係るスカンジウムの回収方法では、逆添加法によりシュウ酸化処理を行う工程において、反応温度を特定の範囲に調整してシュウ酸化反応を生じさせることを特徴としている。具体的には、シュウ酸化処理における反応温度を２０℃以上３５℃以下としてシュウ酸化反応を生じさせる。
The scandium recovery method according to the present embodiment is characterized in that the reaction temperature is adjusted to a specific range to cause a succulent oxidation reaction in the step of performing the sulphate oxidation treatment by the back addition method. Specifically, the shu oxidation reaction is caused by setting the reaction temperature in the shu oxidation treatment to 20 ° C. or higher and 35 ° C. or lower.
このような方法によれば、スカンジウム含有溶液に含まれる不純物金属元素がシュウ酸塩として沈澱物化することを抑え、得られるシュウ酸スカンジウムの結晶に含まれる不純物品位を効果的に低減できる。加えて、シュウ酸スカンジウム中の不純物品位のばらつきを抑えることもでき、高純度なシュウ酸スカンジウムを安定的に得ることができる。
According to such a method, the impurity metal element contained in the scandium-containing solution can be suppressed from becoming a precipitate as oxalate, and the impurity grade contained in the obtained scandium oxalate crystal can be effectively reduced. In addition, it is possible to suppress variations in the impurity grade in scandium oxalate, and it is possible to stably obtain high-purity scandium oxalate.
なお、例えば、このようなシュウ酸化処理を施して得られるシュウ酸スカンジウムの結晶を焙焼することによって、酸化スカンジウムの形態として回収することができる。
Note that, for example, by roasting the crystals of scandium oxalate obtained by subjecting such a scandium oxide treatment, it can be recovered in the form of scandium oxide.
≪２．スカンジウムの回収方法≫
以下、本実施の形態に係るスカンジウムの回収方法についてより詳細に説明する。 ≪2. Scandium recovery method ≫
Hereinafter, the scandium recovery method according to the present embodiment will be described in more detail.
以下、本実施の形態に係るスカンジウムの回収方法についてより詳細に説明する。 ≪2. Scandium recovery method ≫
Hereinafter, the scandium recovery method according to the present embodiment will be described in more detail.
＜２－１．ニッケル酸化鉱の湿式製錬プロセス＞
本実施の形態に係るスカンジウムの回収方法では、上述したように、スカンジウムと、不純物金属元素とを含有する溶液（スカンジウム含有溶液）として、ニッケル酸化鉱石を高圧酸浸出処理して得られた浸出液からニッケルを硫化物として分離した後の溶液（硫化後液）を用いることができる。また、硫化後液に対して、イオン交換処理や溶媒抽出処理を行うことによって不純物成分を除去した溶液を用いることもできる。 <2-1. Wet smelting process of nickel oxide ore ＞
In the method for recovering scandium according to the present embodiment, as described above, as a solution containing scandium and an impurity metal element (scandium-containing solution), a leachate obtained by high-pressure acid leaching treatment of nickel oxide ore is used. A solution after separating nickel as a sulfide (post-sulfide solution) can be used. Further, it is also possible to use a solution from which impurity components have been removed by performing an ion exchange treatment or a solvent extraction treatment on the after sulfidation liquid.
本実施の形態に係るスカンジウムの回収方法では、上述したように、スカンジウムと、不純物金属元素とを含有する溶液（スカンジウム含有溶液）として、ニッケル酸化鉱石を高圧酸浸出処理して得られた浸出液からニッケルを硫化物として分離した後の溶液（硫化後液）を用いることができる。また、硫化後液に対して、イオン交換処理や溶媒抽出処理を行うことによって不純物成分を除去した溶液を用いることもできる。 <2-1. Wet smelting process of nickel oxide ore ＞
In the method for recovering scandium according to the present embodiment, as described above, as a solution containing scandium and an impurity metal element (scandium-containing solution), a leachate obtained by high-pressure acid leaching treatment of nickel oxide ore is used. A solution after separating nickel as a sulfide (post-sulfide solution) can be used. Further, it is also possible to use a solution from which impurity components have been removed by performing an ion exchange treatment or a solvent extraction treatment on the after sulfidation liquid.
これらのスカンジウム含有溶液には、鉄（Ｆｅ）、マンガン（Ｍｎ）、アルミニウム（Ａｌ）、クロム（Ｃｒ）、マグネシウム（Ｍｇ）等の不純物金属元素が含まれる。また、硫化物として分離されなかったニッケル（Ｎｉ）も不純物として含まれることがある。
These scandium-containing solutions contain impurity metal elements such as iron (Fe), manganese (Mn), aluminum (Al), chromium (Cr), and magnesium (Mg). In addition, nickel (Ni) that has not been separated as a sulfide may also be contained as an impurity.
以下では先ず、出発原料とするスカンジウム含有溶液を得るための、ニッケル酸化鉱石の湿式製錬プロセスについて説明する。
Below, first, the hydrometallurgical process of nickel oxide ore for obtaining a scandium-containing solution as a starting material will be described.
図１は、ニッケル酸化鉱石の湿式製錬プロセスの流れを示すフロー図である。ニッケル酸化鉱石の湿式製錬プロセスは、ニッケル酸化鉱石を高温高圧下で硫酸により浸出して浸出スラリーを得る浸出工程Ｓ１１と、浸出スラリーを浸出液と浸出残渣とに固液分離する固液分離工程Ｓ１２と、浸出液に中和剤を添加して不純物を含む中和澱物と中和後液とを得る中和工程Ｓ１３と、中和後液に硫化剤を添加してニッケル硫化物と硫化後液とを得る硫化工程Ｓ１４と、を有する。
FIG. 1 is a flow chart showing the flow of the hydrometallurgical process of nickel oxide ore. The hydrometallurgical process of nickel oxide ore consists of a leaching step S11 in which the nickel oxide ore is leached with sulfuric acid under high temperature and high pressure to obtain a leaching slurry, and a solid-liquid separation step S12 in which the leaching slurry is solid-liquid separated into a leachate and a leachate residue. S13, a neutralization step S13 in which a neutralizing agent is added to the leachate to obtain a neutralized starch containing impurities and a post-neutralizing liquid, and a sulfurizing agent is added to the post-neutralizing liquid to obtain nickel sulfide and a post-sulfurized liquid. It has a sulfurization step S14 for obtaining the above.
（１）浸出工程
浸出工程Ｓ１１は、例えば高温加圧容器（オートクレーブ）等を用い、ニッケル酸化鉱石のスラリーに硫酸を添加するとともに高圧蒸気と高圧空気を供給して、２４０℃～２６０℃の温度下で攪拌処理を施し、ニッケルを含有する浸出液とヘマタイトを含む浸出残渣とからなる浸出スラリーを生成させる工程である。なお、スカンジウムは、ニッケルと共に浸出液に含まれる。 (1) Leaching step In the leaching step S11, for example, a high-temperature pressure vessel (autoclave) or the like is used to add sulfuric acid to a slurry of nickel oxide ore and supply high-pressure steam and high-pressure air to a temperature of 240 ° C to 260 ° C. It is a step of performing a stirring treatment below to generate a leaching slurry composed of a leaching solution containing nickel and a leaching residue containing hematite. Scandium is contained in the leachate together with nickel.
浸出工程Ｓ１１は、例えば高温加圧容器（オートクレーブ）等を用い、ニッケル酸化鉱石のスラリーに硫酸を添加するとともに高圧蒸気と高圧空気を供給して、２４０℃～２６０℃の温度下で攪拌処理を施し、ニッケルを含有する浸出液とヘマタイトを含む浸出残渣とからなる浸出スラリーを生成させる工程である。なお、スカンジウムは、ニッケルと共に浸出液に含まれる。 (1) Leaching step In the leaching step S11, for example, a high-temperature pressure vessel (autoclave) or the like is used to add sulfuric acid to a slurry of nickel oxide ore and supply high-pressure steam and high-pressure air to a temperature of 240 ° C to 260 ° C. It is a step of performing a stirring treatment below to generate a leaching slurry composed of a leaching solution containing nickel and a leaching residue containing hematite. Scandium is contained in the leachate together with nickel.
ここで、ニッケル酸化鉱石としては、主としてリモナイト鉱及びサプロライト鉱等のいわゆるラテライト鉱が挙げられる。ラテライト鉱のニッケル含有量は、通常、０．８～２．５重量％であり、水酸化物又はケイ苦土（ケイ酸マグネシウム）鉱物として含有される。また、これらのニッケル酸化鉱石には、スカンジウムが含まれている。
Here, examples of nickel oxide ore mainly include so-called laterite ores such as limonite ore and saprolite ore. The nickel content of the laterite ore is usually 0.8 to 2.5% by weight, and is contained as a hydroxide or a siliceous earth (magnesium silicate) mineral. In addition, these nickel oxide ores contain scandium.
（２）固液分離工程
固液分離工程Ｓ１２は、上述した浸出工程Ｓ１１で生成した浸出スラリーを多段洗浄して、ニッケル及びコバルトを含む浸出液と、ヘマタイトである浸出残渣とを固液分離する工程である。 (2) Solid-Liquid Separation Step In the solid-liquid separation step S12, the leachate slurry generated in the above-mentioned leachation step S11 is washed in multiple stages to separate the leachate containing nickel and cobalt from the leachate residue which is hematite. Is.
固液分離工程Ｓ１２は、上述した浸出工程Ｓ１１で生成した浸出スラリーを多段洗浄して、ニッケル及びコバルトを含む浸出液と、ヘマタイトである浸出残渣とを固液分離する工程である。 (2) Solid-Liquid Separation Step In the solid-liquid separation step S12, the leachate slurry generated in the above-mentioned leachation step S11 is washed in multiple stages to separate the leachate containing nickel and cobalt from the leachate residue which is hematite. Is.
固液分離工程Ｓ１２では、浸出スラリーを洗浄液と混合した後、シックナー等の固液分離装置を用いて固液分離処理を施す。具体的には、先ず、スラリーが洗浄液により希釈され、次に、スラリー中の浸出残渣がシックナーの沈降物として濃縮される。これにより、浸出残渣に付着するニッケル分をその希釈の度合に応じて減少させることができる。実操業では、このような機能を持つシックナーを多段に連結して用いる。
In the solid-liquid separation step S12, the leachate slurry is mixed with the cleaning liquid, and then the solid-liquid separation treatment is performed using a solid-liquid separation device such as a thickener. Specifically, the slurry is first diluted with a washing liquid, and then the leaching residue in the slurry is concentrated as a thickener sediment. Thereby, the nickel content adhering to the leachate residue can be reduced according to the degree of dilution thereof. In actual operation, thickeners with such functions are used in multiple stages.
（３）中和工程
中和工程Ｓ１３は、浸出液に中和剤を添加してｐＨを調整し、不純物元素を含む中和澱物と中和後液とを得る工程である。中和工程Ｓ１３における中和処理により、ニッケルやコバルト、スカンジウム等の有価金属は中和後液に含まれるようになり、アルミニウムをはじめとした不純物の大部分が中和澱物となる。 (3) Neutralization Step The neutralization step S13 is a step of adding a neutralizing agent to the leachate to adjust the pH to obtain a neutralized starch containing an impurity element and a neutralized liquid. By the neutralization treatment in the neutralization step S13, valuable metals such as nickel, cobalt, and scandium are contained in the liquid after neutralization, and most of the impurities such as aluminum become neutralized starch.
中和工程Ｓ１３は、浸出液に中和剤を添加してｐＨを調整し、不純物元素を含む中和澱物と中和後液とを得る工程である。中和工程Ｓ１３における中和処理により、ニッケルやコバルト、スカンジウム等の有価金属は中和後液に含まれるようになり、アルミニウムをはじめとした不純物の大部分が中和澱物となる。 (3) Neutralization Step The neutralization step S13 is a step of adding a neutralizing agent to the leachate to adjust the pH to obtain a neutralized starch containing an impurity element and a neutralized liquid. By the neutralization treatment in the neutralization step S13, valuable metals such as nickel, cobalt, and scandium are contained in the liquid after neutralization, and most of the impurities such as aluminum become neutralized starch.
中和工程Ｓ１３では、中和剤としては公知のもの使用することができ、例えば、石灰石、消石灰、水酸化ナトリウム等が挙げられる。また、中和処理においては、分離された浸出液の酸化を抑制しながら、ｐＨを１～４の範囲に調整することが好ましく、ｐＨを１．５～２．５の範囲に調整することがより好ましい。ｐＨが１未満であると、中和が不十分となり、中和澱物と中和後液とに分離できない可能性がある。一方で、ｐＨが４を超えると、アルミニウムをはじめとした不純物のみならず、スカンジウムやニッケル等の有価金属も中和澱物に含まれる可能性がある。
In the neutralization step S13, a known neutralizing agent can be used, and examples thereof include limestone, slaked lime, and sodium hydroxide. Further, in the neutralization treatment, it is preferable to adjust the pH to the range of 1 to 4 while suppressing the oxidation of the separated leachate, and it is more preferable to adjust the pH to the range of 1.5 to 2.5. preferable. If the pH is less than 1, neutralization may be insufficient and the neutralized starch and the neutralized liquid may not be separated. On the other hand, when the pH exceeds 4, not only impurities such as aluminum but also valuable metals such as scandium and nickel may be contained in the neutralized starch.
（４）硫化工程
硫化工程Ｓ１４は、中和工程Ｓ１３により得られた中和後液に硫化剤を添加してニッケル硫化物と、硫化後液とを得る工程である。硫化工程Ｓ１４における硫化処理により、ニッケル、コバルト、亜鉛等は硫化物となって回収され、スカンジウム等は硫化後液に残留することになる。したがって、このような湿式製錬プロセスにおける硫化処理により、ニッケルとスカンジウムとを効果的に分離することができる。 (4) Sulfurization Step The sulfurization step S14 is a step of adding a sulfurizing agent to the neutralized liquid obtained in the neutralization step S13 to obtain nickel sulfide and a post-sulfurized liquid. By the sulfurization treatment in the sulfurization step S14, nickel, cobalt, zinc and the like are recovered as sulfurized substances, and scandium and the like remain in the after sulfidation liquid. Therefore, nickel and scandium can be effectively separated by the sulfurization treatment in such a hydrometallurgical process.
硫化工程Ｓ１４は、中和工程Ｓ１３により得られた中和後液に硫化剤を添加してニッケル硫化物と、硫化後液とを得る工程である。硫化工程Ｓ１４における硫化処理により、ニッケル、コバルト、亜鉛等は硫化物となって回収され、スカンジウム等は硫化後液に残留することになる。したがって、このような湿式製錬プロセスにおける硫化処理により、ニッケルとスカンジウムとを効果的に分離することができる。 (4) Sulfurization Step The sulfurization step S14 is a step of adding a sulfurizing agent to the neutralized liquid obtained in the neutralization step S13 to obtain nickel sulfide and a post-sulfurized liquid. By the sulfurization treatment in the sulfurization step S14, nickel, cobalt, zinc and the like are recovered as sulfurized substances, and scandium and the like remain in the after sulfidation liquid. Therefore, nickel and scandium can be effectively separated by the sulfurization treatment in such a hydrometallurgical process.
具体的に、硫化工程Ｓ１４では、得られた中和後液に対して、硫化水素ガス、硫化ナトリウム、水素化硫化ナトリウム等の硫化剤を供給して、不純物成分の少ないニッケルを含む硫化物（ニッケル硫化物）と、ニッケル濃度を低い水準で安定させスカンジウム等を含有させた硫化後液とを生成させる。
Specifically, in the sulfurization step S14, a sulfurizing agent such as hydrogen sulfide gas, sodium sulfide, and sodium hydride sulfide is supplied to the obtained after-neutralization liquid to provide a sulfide containing nickel having a small impurity component (sulfide). Nickel sulfide) and a post-sulfurization liquid containing scandium and the like are produced by stabilizing the nickel concentration at a low level.
硫化工程Ｓ１４における硫化処理では、ニッケル硫化物のスラリーをシックナー等の沈降分離装置を用いて分離処理し、ニッケル硫化物をシックナーの底部より分離回収する一方で、水溶液成分である硫化後液はオーバーフローさせて回収する。
In the sulfurization treatment in the sulfurization step S14, the nickel sulfide slurry is separated and separated using a sedimentation separator such as a thickener, and the nickel sulfide is separated and recovered from the bottom of the thickener, while the after-sulfurization liquid, which is an aqueous solution component, overflows. Let me collect it.
本実施の形態に係るスカンジウムの回収方法では、例えば、上述したようなニッケル酸化鉱石の湿式製錬プロセスにおける各工程を経て得られる、硫酸酸性溶液である硫化後液を回収して出発原料として用いることができる。また、その硫化後液に対して後述するイオン交換処理及び溶媒抽出処理を施して得られた溶液を出発原料とすることができる。スカンジウムの回収方法では、このような溶液から酸化スカンジウムを生成させる。
In the scandium recovery method according to the present embodiment, for example, the post-sulfidation solution, which is an acidic sulfuric acid solution obtained through each step in the hydrometallurgical process of nickel oxide ore as described above, is recovered and used as a starting material. be able to. Further, a solution obtained by subjecting the after-sulfurized liquid to an ion exchange treatment and a solvent extraction treatment, which will be described later, can be used as a starting material. The scandium recovery method produces scandium oxide from such a solution.
＜２－２．イオン交換処理、溶媒抽出処理＞
本実施の形態に係るスカンジウムの回収方法においては、上述したように、スカンジウム含有溶液として、ニッケル酸化鉱石の湿式製錬プロセスの硫化工程を経て得られた硫化後液に対してイオン交換処理及び溶媒抽出処理を施して得られた溶液を用いることができる。このように、硫化後液に対してイオン交換処理及び／又は溶媒抽出処理を施すことで、溶液中の不純物を分離除去してスカンジウムを濃縮することができる。 <2-2. Ion exchange treatment, solvent extraction treatment>
In the method for recovering scandium according to the present embodiment, as described above, as a scandium-containing solution, an ion exchange treatment and a solvent are applied to the post-sulfurized liquid obtained through the hydrometallurgical step of the wet smelting process of nickel oxide ore. The solution obtained by subjecting the extraction treatment can be used. By subjecting the post-sulfidation liquid to an ion exchange treatment and / or a solvent extraction treatment in this way, impurities in the solution can be separated and removed to concentrate scandium.
本実施の形態に係るスカンジウムの回収方法においては、上述したように、スカンジウム含有溶液として、ニッケル酸化鉱石の湿式製錬プロセスの硫化工程を経て得られた硫化後液に対してイオン交換処理及び溶媒抽出処理を施して得られた溶液を用いることができる。このように、硫化後液に対してイオン交換処理及び／又は溶媒抽出処理を施すことで、溶液中の不純物を分離除去してスカンジウムを濃縮することができる。 <2-2. Ion exchange treatment, solvent extraction treatment>
In the method for recovering scandium according to the present embodiment, as described above, as a scandium-containing solution, an ion exchange treatment and a solvent are applied to the post-sulfurized liquid obtained through the hydrometallurgical step of the wet smelting process of nickel oxide ore. The solution obtained by subjecting the extraction treatment can be used. By subjecting the post-sulfidation liquid to an ion exchange treatment and / or a solvent extraction treatment in this way, impurities in the solution can be separated and removed to concentrate scandium.
以下では、イオン交換処理、溶媒抽出処理についてそれぞれ説明する。なお、溶媒抽出処理について、イオン交換処理を経て得られた溶離液に対して処理を施す態様を例にして説明しているが、イオン交換処理を行わず溶媒抽出処理のみを行うようにしてもよい。
Below, the ion exchange treatment and the solvent extraction treatment will be described respectively. Although the solvent extraction treatment is described by taking as an example a mode in which the eluent obtained through the ion exchange treatment is treated, it is possible to perform only the solvent extraction treatment without performing the ion exchange treatment. good.
（１）イオン交換処理
硫化後液には、不純物としてアルミニウムやクロム等が含まれている。このことから、溶液中のスカンジウムを酸化スカンジウムとして回収するにあたり、それら不純物を除去してスカンジウムを濃縮させることが好ましい。スカンジウムを濃縮させる方法としては、キレート樹脂を使用したイオン交換処理による方法が挙げられる。 (1) Ion exchange treatment The post-sulfidation liquid contains aluminum, chromium and the like as impurities. For this reason, when recovering scandium in the solution as scandium oxide, it is preferable to remove these impurities and concentrate the scandium. Examples of the method for concentrating scandium include a method by ion exchange treatment using a chelate resin.
硫化後液には、不純物としてアルミニウムやクロム等が含まれている。このことから、溶液中のスカンジウムを酸化スカンジウムとして回収するにあたり、それら不純物を除去してスカンジウムを濃縮させることが好ましい。スカンジウムを濃縮させる方法としては、キレート樹脂を使用したイオン交換処理による方法が挙げられる。 (1) Ion exchange treatment The post-sulfidation liquid contains aluminum, chromium and the like as impurities. For this reason, when recovering scandium in the solution as scandium oxide, it is preferable to remove these impurities and concentrate the scandium. Examples of the method for concentrating scandium include a method by ion exchange treatment using a chelate resin.
図２は、キレート樹脂を使用したイオン交換反応により行うイオン交換処理の流れの一例を示すフロー図である。なお、図２では、イオン交換処理により得られたスカンジウム溶離液を溶媒抽出処理に付すまでの流れを併せて示す。イオン交換処理では、ニッケル酸化鉱石の湿式製錬プロセスにおける硫化工程Ｓ１４（図１）を経て得られた硫化後液を、キレート樹脂に接触させることによってその硫化後液中のスカンジウムをキレート樹脂に吸着させ、スカンジウム（Ｓｃ）溶離液を得るというものである。
FIG. 2 is a flow chart showing an example of the flow of an ion exchange process performed by an ion exchange reaction using a chelate resin. In addition, FIG. 2 also shows the flow until the scandium eluent obtained by the ion exchange treatment is subjected to the solvent extraction treatment. In the ion exchange treatment, the post-sulfurization liquid obtained through the sulfurization step S14 (FIG. 1) in the hydrometallurgical process of nickel oxide ore is brought into contact with the chelate resin, and the scandium in the post-sulfurization liquid is adsorbed on the chelate resin. The scandium (Sc) eluent is obtained.
イオン交換処理の態様（各工程）は、特に限定されないが、例えば図２に示すように、硫化後液をキレート樹脂に接触させてスカンジウムをキレート樹脂に吸着させる吸着工程Ｓ２１と、キレート樹脂に硫酸を接触させてキレート樹脂に吸着したアルミニウムを除去するアルミニウム除去工程Ｓ２２と、アルミニウム除去工程Ｓ２２を経たキレート樹脂に硫酸を接触させてスカンジウム溶離液を得るスカンジウム溶離工程Ｓ２３と、スカンジウム溶離工程Ｓ２３を経たキレート樹脂に硫酸を接触させて吸着工程Ｓ２１にてキレート樹脂に吸着したクロムを除去するクロム除去工程Ｓ２４と、を有するものを例示できる。
The mode (each step) of the ion exchange treatment is not particularly limited, but as shown in FIG. 2, for example, an adsorption step S21 in which the post-sulfurized liquid is brought into contact with the chelate resin to adsorb scandium to the chelate resin, and sulfuric acid is added to the chelate resin. The aluminum removal step S22 for removing the aluminum adsorbed on the chelate resin by contacting the chelate resin, the scandium elution step S23 for obtaining the scandium eluent by contacting sulfuric acid with the chelate resin that has undergone the aluminum removal step S22, and the scandium elution step S23. An example thereof includes a chrome removing step S24 in which sulfuric acid is brought into contact with the chelate resin and the chrome adsorbed on the chelate resin is removed in the adsorption step S21.
［吸着工程］
吸着工程Ｓ２１では、硫化後液をキレート樹脂に接触させてスカンジウムをキレート樹脂に吸着させる。キレート樹脂の種類は特に限定されず、例えばイミノジ酢酸を官能基とする樹脂を用いることができる。 [Adsorption process]
In the adsorption step S21, the post-sulfurized liquid is brought into contact with the chelate resin to adsorb scandium to the chelate resin. The type of chelate resin is not particularly limited, and for example, a resin having iminodiacetic acid as a functional group can be used.
吸着工程Ｓ２１では、硫化後液をキレート樹脂に接触させてスカンジウムをキレート樹脂に吸着させる。キレート樹脂の種類は特に限定されず、例えばイミノジ酢酸を官能基とする樹脂を用いることができる。 [Adsorption process]
In the adsorption step S21, the post-sulfurized liquid is brought into contact with the chelate resin to adsorb scandium to the chelate resin. The type of chelate resin is not particularly limited, and for example, a resin having iminodiacetic acid as a functional group can be used.
［アルミニウム除去工程］
アルミニウム除去工程Ｓ２２では、吸着工程Ｓ２１でスカンジウムを吸着したキレート樹脂に０．１Ｎ以下の硫酸を接触させ、キレート樹脂に吸着したアルミニウムを除去する。なお、アルミニウムを除去する際、ｐＨを１以上２．５以下の範囲に維持することが好ましく、１．５以上２．０以下の範囲に維持することがより好ましい。 [Aluminum removal process]
In the aluminum removal step S22, sulfuric acid of 0.1 N or less is brought into contact with the chelate resin adsorbed with scandium in the adsorption step S21 to remove the aluminum adsorbed on the chelate resin. When removing aluminum, it is preferable to maintain the pH in the range of 1 or more and 2.5 or less, and it is more preferable to maintain the pH in the range of 1.5 or more and 2.0 or less.
アルミニウム除去工程Ｓ２２では、吸着工程Ｓ２１でスカンジウムを吸着したキレート樹脂に０．１Ｎ以下の硫酸を接触させ、キレート樹脂に吸着したアルミニウムを除去する。なお、アルミニウムを除去する際、ｐＨを１以上２．５以下の範囲に維持することが好ましく、１．５以上２．０以下の範囲に維持することがより好ましい。 [Aluminum removal process]
In the aluminum removal step S22, sulfuric acid of 0.1 N or less is brought into contact with the chelate resin adsorbed with scandium in the adsorption step S21 to remove the aluminum adsorbed on the chelate resin. When removing aluminum, it is preferable to maintain the pH in the range of 1 or more and 2.5 or less, and it is more preferable to maintain the pH in the range of 1.5 or more and 2.0 or less.
［スカンジウム溶離工程］
スカンジウム溶離工程Ｓ２３では、アルミニウム除去工程Ｓ２２を経たキレート樹脂に０．３Ｎ以上３Ｎ未満の硫酸を接触させ、スカンジウム溶離液を得る。スカンジウム溶離液を得るに際して、溶離液に用いる硫酸の規定度を０．３Ｎ以上３Ｎ未満の範囲に維持することが好ましく、０．５Ｎ以上２Ｎ未満の範囲に維持することがより好ましい。 [Scandium elution process]
In the scandium elution step S23, sulfuric acid of 0.3N or more and less than 3N is brought into contact with the chelate resin that has undergone the aluminum removal step S22 to obtain a scandium eluent. When obtaining the scandium eluate, the normality of sulfuric acid used in the eluent is preferably maintained in the range of 0.3N or more and less than 3N, and more preferably maintained in the range of 0.5N or more and less than 2N.
スカンジウム溶離工程Ｓ２３では、アルミニウム除去工程Ｓ２２を経たキレート樹脂に０．３Ｎ以上３Ｎ未満の硫酸を接触させ、スカンジウム溶離液を得る。スカンジウム溶離液を得るに際して、溶離液に用いる硫酸の規定度を０．３Ｎ以上３Ｎ未満の範囲に維持することが好ましく、０．５Ｎ以上２Ｎ未満の範囲に維持することがより好ましい。 [Scandium elution process]
In the scandium elution step S23, sulfuric acid of 0.3N or more and less than 3N is brought into contact with the chelate resin that has undergone the aluminum removal step S22 to obtain a scandium eluent. When obtaining the scandium eluate, the normality of sulfuric acid used in the eluent is preferably maintained in the range of 0.3N or more and less than 3N, and more preferably maintained in the range of 0.5N or more and less than 2N.
［クロム除去工程］
クロム除去工程Ｓ２４では、スカンジウム溶離工程Ｓ２３を経たキレート樹脂に３Ｎ以上の硫酸を接触させ、キレート樹脂に吸着したクロムを除去する。クロムを除去する際に、溶離液に用いる硫酸の規定度が３Ｎを下回ると、クロムが適切にキレート樹脂から除去されないため、好ましくない。 [Chromium removal process]
In the chromium removing step S24, sulfuric acid of 3N or more is brought into contact with the chelate resin that has undergone the scandium elution step S23 to remove chromium adsorbed on the chelate resin. When the normality of sulfuric acid used in the eluent is less than 3N when removing chromium, it is not preferable because chromium is not properly removed from the chelate resin.
クロム除去工程Ｓ２４では、スカンジウム溶離工程Ｓ２３を経たキレート樹脂に３Ｎ以上の硫酸を接触させ、キレート樹脂に吸着したクロムを除去する。クロムを除去する際に、溶離液に用いる硫酸の規定度が３Ｎを下回ると、クロムが適切にキレート樹脂から除去されないため、好ましくない。 [Chromium removal process]
In the chromium removing step S24, sulfuric acid of 3N or more is brought into contact with the chelate resin that has undergone the scandium elution step S23 to remove chromium adsorbed on the chelate resin. When the normality of sulfuric acid used in the eluent is less than 3N when removing chromium, it is not preferable because chromium is not properly removed from the chelate resin.
このようなイオン交換処理により、アルミニウムやクロム等の不純物が除去されてスカンジウムが濃縮されたスカンジウム溶離液を得ることができる。なお、得られたスカンジウム溶離液に対して再び同様のイオン交換処理を繰り返すことで、スカンジウム溶離液の濃度を高めることができる。繰り返し回数としては、回数が多いほど回収されるスカンジウムの濃度が高まるが、多く繰り返し過ぎても回収されるスカンジウムの濃度上昇の程度は小さくなるため、工業的には８回以下程度であることが好ましい。
By such an ion exchange treatment, impurities such as aluminum and chromium are removed, and a scandium eluent in which scandium is concentrated can be obtained. By repeating the same ion exchange treatment on the obtained scandium eluate again, the concentration of the scandium eluent can be increased. As for the number of repetitions, the concentration of recovered scandium increases as the number of repetitions increases, but the degree of increase in the concentration of recovered scandium decreases even if the number of repetitions is too large, so it is industrially about 8 times or less. preferable.
（２）溶媒抽出処理
溶媒抽出処理では、上述したイオン交換処理を経て得られたスカンジウム（Ｓｃ）溶離液を所定の抽出剤に接触させて、スカンジウムを抽出する。 (2) Solvent Extraction Treatment In the solvent extraction treatment, the scandium (Sc) eluent obtained through the above-mentioned ion exchange treatment is brought into contact with a predetermined extractant to extract scandium.
溶媒抽出処理では、上述したイオン交換処理を経て得られたスカンジウム（Ｓｃ）溶離液を所定の抽出剤に接触させて、スカンジウムを抽出する。 (2) Solvent Extraction Treatment In the solvent extraction treatment, the scandium (Sc) eluent obtained through the above-mentioned ion exchange treatment is brought into contact with a predetermined extractant to extract scandium.
溶媒抽出に使用する抽出剤としては、特に限定されず、アミン系抽出剤、リン酸系抽出剤等を使用することができる。また、抽出剤の種類に応じて、抽出剤を含む有機溶媒中に抽出対象のスカンジウムを抽出することができ、あるいは、抽出剤に不純物成分を選択的に抽出させ、抽残液中にスカンジウムを残存させるようにすることができる。例えば、アミン系抽出剤を用いた場合には、スカンジウムとの選択性が低い抽出剤であることから、有機溶媒中に不純物成分が選択的に抽出され、抽残液にスカンジウムが濃縮される。
The extractant used for solvent extraction is not particularly limited, and an amine-based extractant, a phosphoric acid-based extractant, or the like can be used. Further, depending on the type of the extractant, the scandium to be extracted can be extracted in an organic solvent containing the extractant, or the extractant can selectively extract the impurity component and the scandium is contained in the extraction residue. It can be made to remain. For example, when an amine-based extractant is used, since it is an extractant having low selectivity with scandium, impurity components are selectively extracted in an organic solvent, and scandium is concentrated in the extraction residue.
溶媒抽出処理の態様（各工程）は、特に限定されないが、スカンジウム溶離液と抽出剤とを混合して不純物を抽出した抽出後有機溶媒とスカンジウムを含む抽残液とに分離する抽出工程Ｓ３１と、抽出後有機溶媒に塩酸溶液又は硫酸溶液を混合して抽出後有機溶媒に微量含まれるスカンジウムを分離するスクラビング工程Ｓ３２と、洗浄後有機溶媒に逆抽出始液を混合して洗浄後有機溶媒から不純物を逆抽出し、逆抽出液を得る逆抽出工程Ｓ３３と、を有するものを例示できる。このように、溶媒抽出処理を行うことで、スカンジウム溶離液に含まれるスカンジウムの純度をより高めることができる。
The mode (each step) of the solvent extraction treatment is not particularly limited, but the extraction step S31 and the extraction step S31 in which the scandium eluent and the extractant are mixed to extract impurities and then separated into an organic solvent and a drawing residue containing scandium. The scrubbing step S32, in which a hydrochloric acid solution or a sulfuric acid solution is mixed with the organic solvent after extraction to separate a trace amount of scandium contained in the organic solvent after extraction, and the back extraction starting solution is mixed with the organic solvent after washing, and the organic solvent is used after washing. An example thereof includes a back extraction step S33 in which impurities are back-extracted to obtain a back-extract solution. By performing the solvent extraction treatment in this way, the purity of scandium contained in the scandium eluent can be further increased.
［抽出工程］
抽出工程Ｓ３１では、スカンジウム含有溶液と、抽出剤を含む有機溶媒とを混合して、有機溶媒中に不純物を選択的に抽出し、不純物を含有する有機溶媒と、スカンジウムを濃縮させた抽残液とを得る。 [Extraction process]
In the extraction step S31, a scandium-containing solution and an organic solvent containing an extractant are mixed, impurities are selectively extracted into the organic solvent, and the organic solvent containing the impurities and the scandium-concentrated extract residue liquid. And get.
抽出工程Ｓ３１では、スカンジウム含有溶液と、抽出剤を含む有機溶媒とを混合して、有機溶媒中に不純物を選択的に抽出し、不純物を含有する有機溶媒と、スカンジウムを濃縮させた抽残液とを得る。 [Extraction process]
In the extraction step S31, a scandium-containing solution and an organic solvent containing an extractant are mixed, impurities are selectively extracted into the organic solvent, and the organic solvent containing the impurities and the scandium-concentrated extract residue liquid. And get.
抽出剤としては、例えばアミン系抽出剤を用いる。アミン系抽出剤としては、１級アミンであるＰｒｉｍｅｎｅＪＭ－Ｔ、２級アミンであるＬＡ－１、３級アミンであるＴＮＯＡ（Ｔｒｉ－ｎ－ｏｃｔｙｌａｍｉｎｅ）、ＴＩＯＡ（Ｔｒｉ－ｉ－ｏｃｔｙｌａｍｉｎｅ）等の商品名で知られるアミン系抽出剤を用いることができる。
As the extractant, for example, an amine-based extractant is used. As the amine-based extractant, products such as PrimeneJM-T, which is a primary amine, LA-1, which is a secondary amine, TNOA (Tri-n-octylamine), which is a tertiary amine, and TIOA (Tri-i-octylamine). An amine-based extractant known by the name can be used.
抽出時においては、アミン系抽出剤等の抽出剤を、例えば炭化水素系の有機溶媒等で希釈して使用することが好ましい。有機溶媒中の抽出剤濃度としては、特に限定されないが、抽出時、後述する逆抽出時における相分離性等を考慮すると、１体積％以上１０体積％以下程度であることが好ましく、特に５体積％程度であることがより好ましい。また、抽出時における、有機溶媒とスカンジウム含有溶液との体積割合としては、特に限定されないが、スカンジウム含有溶液中のメタルモル量に対して有機溶媒モル量を０．０１倍以上０．１倍以下程度にすることが好ましい。
At the time of extraction, it is preferable to dilute an extractant such as an amine-based extractant with a hydrocarbon-based organic solvent or the like before use. The concentration of the extractant in the organic solvent is not particularly limited, but is preferably about 1% by volume or more and 10% by volume or less, particularly 5 volumes, in consideration of phase separation during extraction and back extraction described later. It is more preferably about%. The volume ratio of the organic solvent to the scandium-containing solution at the time of extraction is not particularly limited, but the amount of the organic solvent mol is about 0.01 times or more and 0.1 times or less with respect to the amount of metal in the scandium-containing solution. Is preferable.
［スクラビング（洗浄）工程］
抽出工程Ｓ３１において、スカンジウム含有溶液から不純物を抽出させた有機溶媒中にスカンジウムが僅かに共存する場合には、得られた抽出液を逆抽出する前に、その有機溶媒（有機相）に対してスクラビング（洗浄）処理を施し、スカンジウムを水相に分離させて抽出剤から回収することが好ましい（スクラビング工程Ｓ３２）。スクラビング工程Ｓ３２を設けて有機溶媒を洗浄し、抽出剤により抽出された僅かなスカンジウムを分離させることで、洗浄液中にスカンジウムを分離させることができ、スカンジウムの回収率をより一層に高めることができる。 [Scrubbing (cleaning) process]
In the extraction step S31, when scandium is slightly coexisted in the organic solvent obtained by extracting impurities from the scandium-containing solution, the obtained extract is subjected to the organic solvent (organic phase) before back extraction. It is preferable to perform a scrubbing (washing) treatment to separate the scandium into an aqueous phase and recover it from the extractant (scrubbing step S32). By providing the scrubbing step S32 to wash the organic solvent and separating a small amount of scandium extracted by the extractant, scandium can be separated into the washing liquid, and the scandium recovery rate can be further increased. ..
抽出工程Ｓ３１において、スカンジウム含有溶液から不純物を抽出させた有機溶媒中にスカンジウムが僅かに共存する場合には、得られた抽出液を逆抽出する前に、その有機溶媒（有機相）に対してスクラビング（洗浄）処理を施し、スカンジウムを水相に分離させて抽出剤から回収することが好ましい（スクラビング工程Ｓ３２）。スクラビング工程Ｓ３２を設けて有機溶媒を洗浄し、抽出剤により抽出された僅かなスカンジウムを分離させることで、洗浄液中にスカンジウムを分離させることができ、スカンジウムの回収率をより一層に高めることができる。 [Scrubbing (cleaning) process]
In the extraction step S31, when scandium is slightly coexisted in the organic solvent obtained by extracting impurities from the scandium-containing solution, the obtained extract is subjected to the organic solvent (organic phase) before back extraction. It is preferable to perform a scrubbing (washing) treatment to separate the scandium into an aqueous phase and recover it from the extractant (scrubbing step S32). By providing the scrubbing step S32 to wash the organic solvent and separating a small amount of scandium extracted by the extractant, scandium can be separated into the washing liquid, and the scandium recovery rate can be further increased. ..
スクラビングに用いる溶液（洗浄溶液）としては、硫酸溶液や塩酸溶液等を使用することができる。また、水に可溶性の塩化物や硫酸塩を添加したものを使用することもできる。具体的に、洗浄溶液として硫酸溶液を用いる場合には、１．０ｍｏｌ／Ｌ以上３．０ｍｏｌ／Ｌ以下の濃度範囲のものを使用することが好ましい。
As the solution (washing solution) used for scrubbing, a sulfuric acid solution, a hydrochloric acid solution, or the like can be used. Further, it is also possible to use water to which soluble chloride or sulfate is added. Specifically, when a sulfuric acid solution is used as the cleaning solution, it is preferable to use a solution having a concentration range of 1.0 mol / L or more and 3.0 mol / L or less.
洗浄段数（回数）としては、不純物元素の種類、濃度にも依存することからそれぞれの抽出剤や抽出条件によって適宜変更することができる。例えば、有機相（Ｏ）と水相（Ａ）の相比Ｏ／Ａ＝１とした場合、３～５段程度の段数とすることにより、有機溶媒中に抽出されたスカンジウムを分析装置の検出下限未満まで分離することができる。
Since the number of cleaning stages (number of times) depends on the type and concentration of impurity elements, it can be appropriately changed depending on each extractant and extraction conditions. For example, when the phase ratio O / A of the organic phase (O) and the aqueous phase (A) is O / A = 1, the number of stages is about 3 to 5, and the scandium extracted in the organic solvent is detected by the analyzer. It can be separated to less than the lower limit.
［逆抽出工程］
逆抽出工程Ｓ３３では、抽出工程Ｓ３１にて不純物を抽出した有機溶媒から、不純物を逆抽出する。具体的に、逆抽出工程Ｓ３３では、抽出剤を含む有機溶媒に逆抽出溶液（逆抽出始液）を添加して混合することで、抽出工程Ｓ３１における抽出処理とは逆の反応を生じさせて不純物を逆抽出し、不純物を含む逆抽出後液を得る。 [Reverse extraction process]
In the back extraction step S33, impurities are back extracted from the organic solvent from which the impurities have been extracted in the extraction step S31. Specifically, in the back extraction step S33, a back extraction solution (back extraction starting solution) is added to an organic solvent containing an extractant and mixed to cause a reaction opposite to the extraction process in the extraction step S31. The impurities are back-extracted to obtain a liquid after back-extraction containing the impurities.
逆抽出工程Ｓ３３では、抽出工程Ｓ３１にて不純物を抽出した有機溶媒から、不純物を逆抽出する。具体的に、逆抽出工程Ｓ３３では、抽出剤を含む有機溶媒に逆抽出溶液（逆抽出始液）を添加して混合することで、抽出工程Ｓ３１における抽出処理とは逆の反応を生じさせて不純物を逆抽出し、不純物を含む逆抽出後液を得る。 [Reverse extraction process]
In the back extraction step S33, impurities are back extracted from the organic solvent from which the impurities have been extracted in the extraction step S31. Specifically, in the back extraction step S33, a back extraction solution (back extraction starting solution) is added to an organic solvent containing an extractant and mixed to cause a reaction opposite to the extraction process in the extraction step S31. The impurities are back-extracted to obtain a liquid after back-extraction containing the impurities.
逆抽出溶液である炭酸塩を含有する溶液の濃度としては、過剰な使用を抑制する観点から、例えば０．５ｍｏｌ／Ｌ以上２ｍｏｌ／Ｌ以下程度とすることが好ましい。
The concentration of the solution containing carbonate, which is a back-extraction solution, is preferably about 0.5 mol / L or more and 2 mol / L or less from the viewpoint of suppressing excessive use.
なお、スクラビング工程Ｓ３２にて抽出剤を含む有機溶媒に対してスクラビング処理を施した場合には、同様に、スクラビング後の抽出剤に対して逆抽出溶液を添加して混合することによって逆抽出処理を行うことができる。
When the organic solvent containing the extractant is subjected to the scrubbing treatment in the scrubbing step S32, the back-extraction treatment is similarly performed by adding the back-extraction solution to the scrubbing extractant and mixing it. It can be performed.
このようにして抽出後の抽出剤又はスクラビング後の抽出剤に炭酸ナトリウム等の炭酸塩溶液を添加し、逆抽出処理を行って不純物を分離させた後の抽出剤は、再び、抽出工程Ｓ３１における抽出処理に用いる抽出剤として繰り返して使用することができる。
The extractant after adding a carbonate solution such as sodium carbonate to the extractant after extraction or the extractant after scrubbing in this way and performing a back-extraction treatment to separate impurities is again in the extraction step S31. It can be repeatedly used as an extractant used in the extraction process.
＜２－３．シュウ酸化処理＞
本実施の形態に係るスカンジウムの回収方法では、スカンジウム含有溶液に対してシュウ酸化処理を施してスカンジウムをシュウ酸塩（シュウ酸スカンジウム）とする工程を有する。具体的には、上述した溶媒抽出処理を経て得られた逆抽出物であるスカンジウム含有溶液を用いて、シュウ酸スカンジウムの結晶を生成させるシュウ酸化処理を行う。このように、シュウ酸化処理によってスカンジウムをシュウ酸塩とすることで、濾過性等のハンドリング性を向上させることができ、スカンジウムを効率的に回収することができる。 <2-3. Shu oxidation treatment>
The scandium recovery method according to the present embodiment includes a step of subjecting a scandium-containing solution to an oxalate treatment to convert scandium into an oxalate (scandium oxalate). Specifically, a scandium-containing solution, which is a back extract obtained through the above-mentioned solvent extraction treatment, is used to perform a scandium oxidation treatment for forming scandium oxalate crystals. As described above, by converting scandium into oxalate by the oxalate oxidation treatment, handling properties such as filterability can be improved, and scandium can be efficiently recovered.
本実施の形態に係るスカンジウムの回収方法では、スカンジウム含有溶液に対してシュウ酸化処理を施してスカンジウムをシュウ酸塩（シュウ酸スカンジウム）とする工程を有する。具体的には、上述した溶媒抽出処理を経て得られた逆抽出物であるスカンジウム含有溶液を用いて、シュウ酸スカンジウムの結晶を生成させるシュウ酸化処理を行う。このように、シュウ酸化処理によってスカンジウムをシュウ酸塩とすることで、濾過性等のハンドリング性を向上させることができ、スカンジウムを効率的に回収することができる。 <2-3. Shu oxidation treatment>
The scandium recovery method according to the present embodiment includes a step of subjecting a scandium-containing solution to an oxalate treatment to convert scandium into an oxalate (scandium oxalate). Specifically, a scandium-containing solution, which is a back extract obtained through the above-mentioned solvent extraction treatment, is used to perform a scandium oxidation treatment for forming scandium oxalate crystals. As described above, by converting scandium into oxalate by the oxalate oxidation treatment, handling properties such as filterability can be improved, and scandium can be efficiently recovered.
なお、溶媒抽出処理を経て得られたスカンジウム含有溶液は、上述したイオン交換処理や溶媒抽出処理によって大部分の不純物金属元素が除去されてスカンジウムが濃縮された溶液ではある。ところが、これらの処理によって除去されなかった不純物金属元素が一定量含まれている（後述する実施例における表１に示すシュウ酸化始液の組成を参照）。具体的に、その不純物金属元素としては、少なくとも、鉄、ニッケル、マンガン、アルミニウム、クロム、マグネシウム等が挙げられる。
The scandium-containing solution obtained through the solvent extraction treatment is a solution in which most of the impurity metal elements have been removed by the above-mentioned ion exchange treatment and the solvent extraction treatment to concentrate the scandium. However, it contains a certain amount of impurity metal elements that were not removed by these treatments (see the composition of the Shu oxidation starting solution shown in Table 1 in Examples described later). Specifically, examples of the impurity metal element include at least iron, nickel, manganese, aluminum, chromium, magnesium and the like.
ここで、シュウ酸化処理の方法としては、いわゆる「逆添加」法により行う。具体的には、所定の容器に収容したシュウ酸溶液に、スカンジウム含有溶液を徐々に添加していくことによって、シュウ酸スカンジウムの固体結晶を析出生成させる方法により行う。このような逆添加法に基づくシュウ酸化処理によれば、過酸化水素等の酸化剤を添加して酸化還元電位（ＯＲＰ）を調整する操作を行うことなく、不純物金属元素である鉄のシュウ酸化を抑制し、シュウ酸鉄（II）の沈澱生成を防ぐことができる。
Here, as the method of shu oxidation treatment, the so-called "reverse addition" method is used. Specifically, the scandium-containing solution is gradually added to the oxalic acid solution contained in a predetermined container to precipitate and generate solid crystals of scandium oxalate. According to the shu oxidation treatment based on such a back addition method, iron shu oxidation, which is an impurity metal element, is performed without adding an oxidizing agent such as hydrogen peroxide to adjust the redox potential (ORP). Can be suppressed and the formation of iron (II) oxalate precipitates can be prevented.
そして、逆添加法によるシュウ酸化処理に際しては、反応温度を特定の範囲、具体的には２０℃以上３５℃以下とすることを特徴としている。また、好ましくは、２０℃以上３０℃以下とし、より好ましくは、２３℃以上３０℃以下とする。
The reaction temperature is set to a specific range, specifically, 20 ° C. or higher and 35 ° C. or lower in the shu oxidation treatment by the reverse addition method. Further, it is preferably 20 ° C. or higher and 30 ° C. or lower, and more preferably 23 ° C. or higher and 30 ° C. or lower.
従来のシュウ酸化処理においては、スカンジウム含有溶液にシュウ酸溶液を添加する、いわゆる「正添加」法（標準添加法）により行うことが一般的であり、また、その反応温度も成り行きとしていた。ところが、そのシュウ酸化処理では、スカンジウムのシュウ酸塩を優先的に生じさせて不純物金属元素の沈澱物化を抑制できるものの、処理条件に依存して、得られるシュウ酸スカンジウム中の不純物品位にばらつきが生じやすく、安定的に所定のスペックのシュウ酸スカンジウムを得ることができなかった。
In the conventional oxalic acid treatment, it is common to add an oxalic acid solution to a scandium-containing solution, that is, a so-called "normal addition" method (standard addition method), and the reaction temperature is also a matter of course. However, in the oxalic acid treatment, although scandium oxalate can be preferentially generated to suppress the precipitation of impurity metal elements, the quality of impurities in the obtained scandium oxalate varies depending on the treatment conditions. It was easy to occur, and it was not possible to stably obtain scandium oxalate with the specified specifications.
シュウ酸化処理では、希土類元素であるスカンジウム以外の金属元素もシュウ酸と反応して錯体を形成するが、錯体の安定度が低い不純物金属元素は、シュウ酸スカンジウムの沈澱に吸着して共沈する。そして、このような錯体の安定度は、金属元素の種類のみならずシュウ酸化処理の条件にも依存し、これにより、得られるシュウ酸スカンジウム中の不純物品位にばらつきが生じることになると考えられる。
In the oxalate oxidation treatment, metal elements other than scandium, which is a rare earth element, also react with oxalic acid to form a complex, but impurity metal elements with low complex stability are adsorbed on the precipitate of scandium oxalate and co-precipitate. .. It is considered that the stability of such a complex depends not only on the type of the metal element but also on the conditions of the oxalic acid treatment, which causes variations in the impurity grade in the obtained scandium oxalate.
本実施の形態においては、上述したように、所定の容器に収容したシュウ酸溶液にスカンジウム含有溶液を添加してシュウ酸化反応を生じさせる「逆添加」法によるシュウ酸化処理を行い、かつ、そのときの反応温度を２０℃以上３５℃以下とするようにしている。このことにより、スカンジウム含有溶液に含まれる不純物金属元素のシュウ酸塩化を抑制してシュウ酸スカンジウムの結晶に含まれる不純物品位を有効に低減できる。またそれに加え、シュウ酸化処理の条件に依らず、結晶に含まれる不純物品位のばらつきを抑えることができる。特に、スカンジウム含有溶液に含まれる不純物金属元素のうち、鉄（Ｆｅ）、ニッケル（Ｎｉ）、及びマンガン（Ｍｎ）について品位のばらつきを効果的に抑えることができる。
In the present embodiment, as described above, a scandium-containing solution is added to the oxalic acid solution contained in a predetermined container to cause a oxalic acid reaction, and the oxalic acid treatment is carried out by a "reverse addition" method. The reaction temperature at this time is set to 20 ° C. or higher and 35 ° C. or lower. This makes it possible to suppress the oxalate formation of the impurity metal element contained in the scandium-containing solution and effectively reduce the impurity grade contained in the scandium oxalate crystal. In addition, it is possible to suppress variations in the quality of impurities contained in the crystals regardless of the conditions of the shu oxidation treatment. In particular, among the impurity metal elements contained in the scandium-containing solution, the variation in quality of iron (Fe), nickel (Ni), and manganese (Mn) can be effectively suppressed.
反応温度を特定の範囲とすることでシュウ酸スカンジウム中の不純物品位のばらつきを抑えられるメカニズムは不明であるが、シュウ酸化反応において温度によって水和水の数が変化し、これが不純物の溶解度に影響を与えている可能性が考えられる。
The mechanism by which the variation in impurity grade in scandium oxalate can be suppressed by setting the reaction temperature within a specific range is unknown, but the number of hydrated water changes depending on the temperature in the oxalate oxidation reaction, which affects the solubility of impurities. It is possible that it is giving.
このようなシュウ酸化処理の方法によれば、不純物含有スペックが安定した、スカンジウムを高純度に含有するシュウ酸スカンジウムを得ることができ、またそのシュウ酸スカンジウムを焙焼することで、高品質な酸化スカンジウムを得ることができる。
According to such a method of oxalate oxidation treatment, scandium oxalate containing scandium with high purity and stable impurity-containing specifications can be obtained, and by roasting the scandium oxalate, high quality can be obtained. Scandium oxide can be obtained.
図３に、シュウ酸化処理のフロー図を示す。上述したように、本実施の形態においては、逆添加法によるシュウ酸化処理に際して反応温度を２０℃以上３５℃以下とすることを特徴としている。具体的に、シュウ酸化処理は、スカンジウム含有溶液の温度を調整する温度調整工程Ｓ４１と、温度調整した溶液（シュウ酸化始液）を容器に収容したシュウ酸溶液に添加してシュウ酸スカンジウムの結晶を析出させる晶析工程Ｓ４２と、を有する。なお、得られたシュウ酸スカンジウムの結晶は、濾過・洗浄処理を行う濾過・洗浄工程Ｓ４３を経ることによって回収することができる。
FIG. 3 shows a flow chart of the shu oxidation treatment. As described above, the present embodiment is characterized in that the reaction temperature is set to 20 ° C. or higher and 35 ° C. or lower during the oxalate oxidation treatment by the back addition method. Specifically, in the oxalic acid treatment, the temperature adjusting step S41 for adjusting the temperature of the scandium-containing solution and the temperature-adjusted solution (starting solution for oxalic acid) are added to the oxalic acid solution contained in the container to crystallize scandium oxalate. It has a crystallization step S42 for precipitating. The obtained scandium oxalate crystals can be recovered by passing through the filtration / cleaning step S43 in which the filtration / cleaning treatment is performed.
また、晶析工程Ｓ４２での処理に先立って、スカンジウム含有溶液のｐＨを－０．５以上１．０以下の範囲に調整することが好ましい。すなわち、図３には図示しないがｐＨ調整工程を設けて、晶析工程Ｓ４２での処理に供するスカンジウム含有溶液のｐＨを上記の範囲に予め調整する。これにより、シュウ酸鉄（ＩＩ）等の溶解度を上昇させることができ、高価な酸化剤等を用いることなく、不純物の沈澱生成をより効果的に抑制して、より高純度のスカンジウムを回収することができる。なお、スカンジウム含有溶液のｐＨ調整については、温度調整工程Ｓ４１の前に行っても、あるいはその後に行ってもよく、もしくは温度調整と同じタイミングで行ってもよい。
Further, it is preferable to adjust the pH of the scandium-containing solution to a range of −0.5 or more and 1.0 or less prior to the treatment in the crystallization step S42. That is, although not shown in FIG. 3, a pH adjusting step is provided to adjust the pH of the scandium-containing solution to be treated in the crystallization step S42 in advance within the above range. As a result, the solubility of iron (II) oxalate and the like can be increased, and the precipitation formation of impurities can be more effectively suppressed without using an expensive oxidizing agent or the like, and scandium with higher purity can be recovered. be able to. The pH of the scandium-containing solution may be adjusted before or after the temperature adjustment step S41, or may be performed at the same timing as the temperature adjustment.
（温度調整工程）
温度調整工程Ｓ４１では、シュウ酸化処理に供するスカンジウム含有溶液の温度を、２０℃以上３５℃以下、好ましくは２０℃以上３０℃以下、より好ましくは２３℃以上３０℃以下に調整する。このように、スカンジウム含有溶液の温度を２０℃以上３５℃以下の範囲に調整し、その温度を維持して次の晶析工程Ｓ４２で反応を生じさせることで、得られるシュウ酸スカンジウムの結晶に含まれる不純物品位を低減し、また、その不純物品位のばらつきを抑えることができる。 (Temperature adjustment process)
In the temperature adjusting step S41, the temperature of the scandium-containing solution to be subjected to the shu oxidation treatment is adjusted to 20 ° C. or higher and 35 ° C. or lower, preferably 20 ° C. or higher and 30 ° C. or lower, and more preferably 23 ° C. or higher and 30 ° C. or lower. As described above, the temperature of the scandium-containing solution is adjusted to a range of 20 ° C. or higher and 35 ° C. or lower, and the temperature is maintained to cause a reaction in the next crystallization step S42 to obtain scandium oxalate crystals. It is possible to reduce the contained impurity grade and suppress the variation in the impurity grade.
温度調整工程Ｓ４１では、シュウ酸化処理に供するスカンジウム含有溶液の温度を、２０℃以上３５℃以下、好ましくは２０℃以上３０℃以下、より好ましくは２３℃以上３０℃以下に調整する。このように、スカンジウム含有溶液の温度を２０℃以上３５℃以下の範囲に調整し、その温度を維持して次の晶析工程Ｓ４２で反応を生じさせることで、得られるシュウ酸スカンジウムの結晶に含まれる不純物品位を低減し、また、その不純物品位のばらつきを抑えることができる。 (Temperature adjustment process)
In the temperature adjusting step S41, the temperature of the scandium-containing solution to be subjected to the shu oxidation treatment is adjusted to 20 ° C. or higher and 35 ° C. or lower, preferably 20 ° C. or higher and 30 ° C. or lower, and more preferably 23 ° C. or higher and 30 ° C. or lower. As described above, the temperature of the scandium-containing solution is adjusted to a range of 20 ° C. or higher and 35 ° C. or lower, and the temperature is maintained to cause a reaction in the next crystallization step S42 to obtain scandium oxalate crystals. It is possible to reduce the contained impurity grade and suppress the variation in the impurity grade.
スカンジウム含有溶液の温度調整方法としては、特に限定されず、例えばヒーター等を用いて調整することができる。
The temperature adjusting method for the scandium-containing solution is not particularly limited, and can be adjusted by using, for example, a heater or the like.
また、上述のように、シュウ酸化処理においては、容器に収容したシュウ酸溶液にスカンジウム含有溶液を徐々に添加してシュウ酸化反応を生じさせることから、予め、シュウ酸化処理に用いるシュウ酸溶液の温度も２０℃以上３５℃以下の範囲に調整し、その温度を維持して反応させることが好ましい。これにより、反応温度を２０℃以上３５℃以下の範囲に適切に維持させることができ、得られるシュウ酸スカンジウムにおける不純物品位のばらつきをより効果的に抑えることができる。
Further, as described above, in the oxalic acid treatment, since the scandium-containing solution is gradually added to the oxalic acid solution contained in the container to cause the oxalic acid reaction, the oxalic acid solution used for the oxalic acid treatment is previously prepared. It is preferable to adjust the temperature to a range of 20 ° C. or higher and 35 ° C. or lower, and maintain the temperature for reaction. Thereby, the reaction temperature can be appropriately maintained in the range of 20 ° C. or higher and 35 ° C. or lower, and the variation in the impurity grade in the obtained scandium oxalate can be more effectively suppressed.
（晶析工程）
晶析工程Ｓ４２では、反応温度を２０℃以上３５℃以下として、シュウ酸溶液に対してスカンジウム含有溶液（シュウ酸化始液）を添加してスカンジウムをシュウ酸化する反応を生じさせるシュウ酸化処理を施し、スカンジウムのシュウ酸塩（シュウ酸スカンジウムの結晶）を得る。 (Crystalization process)
In the crystallization step S42, the reaction temperature is set to 20 ° C. or higher and 35 ° C. or lower, and a scandium-containing solution (starting solution for oxalic acid) is added to the oxalic acid solution to perform a oxalic acid treatment to cause a reaction to oxidize scandium. , Obtain scandium oxalate (crystals of scandium oxalate).
晶析工程Ｓ４２では、反応温度を２０℃以上３５℃以下として、シュウ酸溶液に対してスカンジウム含有溶液（シュウ酸化始液）を添加してスカンジウムをシュウ酸化する反応を生じさせるシュウ酸化処理を施し、スカンジウムのシュウ酸塩（シュウ酸スカンジウムの結晶）を得る。 (Crystalization process)
In the crystallization step S42, the reaction temperature is set to 20 ° C. or higher and 35 ° C. or lower, and a scandium-containing solution (starting solution for oxalic acid) is added to the oxalic acid solution to perform a oxalic acid treatment to cause a reaction to oxidize scandium. , Obtain scandium oxalate (crystals of scandium oxalate).
シュウ酸化反応の反応温度に関して、反応温度が３５℃よりも高いと、得られるシュウ酸スカンジウム中の不純物品位のばらつきが生じる。また、反応温度が２０℃未満であると、反応速度が低下するとともに、シュウ酸塩の溶解度が減少して供給配管等の好ましくない場所で析出するといった問題が生じる可能性がある。
Regarding the reaction temperature of the oxalate oxidation reaction, if the reaction temperature is higher than 35 ° C., the impurities grade in the obtained scandium oxalate varies. Further, if the reaction temperature is less than 20 ° C., the reaction rate may decrease, and the solubility of the oxalate may decrease, causing a problem that the oxalate precipitates in an unfavorable place such as a supply pipe.
上述したように、反応容器にシュウ酸溶液を収容し、そのシュウ酸溶液にスカンジウム含有溶液を添加して反応を生じさせる「逆添加」法により行う。シュウ酸溶液の量としては、少なくとも、スカンジウム含有溶液中のスカンジウムをシュウ酸塩として析出させるのに必要な当量の１．０５倍以上とすることが好ましく、２．０倍以上とすることがより好ましい。使用量が必要な当量の１．０５倍未満であると、スカンジウムを有効に全量回収できなくなる可能性がある。
As described above, the oxalic acid solution is contained in the reaction vessel, and the scandium-containing solution is added to the oxalic acid solution to cause a reaction by the "reverse addition" method. The amount of the oxalic acid solution is preferably at least 1.05 times or more, more preferably 2.0 times or more the equivalent amount required for precipitating scandium in the scandium-containing solution as an oxalate. preferable. If the amount used is less than 1.05 times the required equivalent, it may not be possible to effectively recover the entire amount of scandium.
また、シュウ酸溶液としては、そのｐＨを－０．５以上１．０以下の範囲に調整したものを用いることが好ましい。特に、スカンジウム含有溶液のｐＨを－０．５以上１．０以下の範囲に調整する場合には、シュウ酸溶液のｐＨも併せて調整することで、より不純物品位を低減させることができ、高純度のスカンジウムを回収することができる。
Further, as the oxalic acid solution, it is preferable to use a solution whose pH is adjusted to the range of -0.5 or more and 1.0 or less. In particular, when adjusting the pH of the scandium-containing solution to the range of -0.5 or more and 1.0 or less, the pH of the oxalic acid solution can also be adjusted to further reduce the impurity grade, resulting in a high pH. Pure scandium can be recovered.
なお、上述した例では、スカンジウム含有溶液を予め２０℃以上３５℃以下の温度に調整し、その温度を維持しながら、当該晶析工程Ｓ４２における反応温度を２０℃以上３５℃以下とする態様について説明したが、これに限られない。すなわち、シュウ酸溶液にスカンジウム含有溶液を添加して反応を生じさせるときの反応温度が２０℃以上３５℃以下の範囲に維持されていればよい。
In the above-mentioned example, the scandium-containing solution is adjusted to a temperature of 20 ° C. or higher and 35 ° C. or lower in advance, and the reaction temperature in the crystallization step S42 is set to 20 ° C. or higher and 35 ° C. or lower while maintaining the temperature. I explained, but it is not limited to this. That is, the reaction temperature when the scandium-containing solution is added to the oxalic acid solution to cause a reaction may be maintained in the range of 20 ° C. or higher and 35 ° C. or lower.
＜２－４．酸化スカンジウムの生成（焙焼）＞
本実施の形態においては、上述のようにしてシュウ酸化処理を行って得られたシュウ酸スカンジウムの結晶を焙焼することによって酸化スカンジウムとする。 <2-4. Generation of scandium oxide (roasting)>
In the present embodiment, scandium oxide is obtained by roasting the crystals of scandium oxalate obtained by performing the oxalate oxidation treatment as described above.
本実施の形態においては、上述のようにしてシュウ酸化処理を行って得られたシュウ酸スカンジウムの結晶を焙焼することによって酸化スカンジウムとする。 <2-4. Generation of scandium oxide (roasting)>
In the present embodiment, scandium oxide is obtained by roasting the crystals of scandium oxalate obtained by performing the oxalate oxidation treatment as described above.
焙焼処理は、シュウ酸化処理により得られたシュウ酸スカンジウムの結晶を水で洗浄し、また乾燥させた後に焙焼する処理である。この焙焼処理を経ることで、スカンジウムを酸化スカンジウムとして回収することができる。
The roasting treatment is a treatment in which the scandium oxalate crystals obtained by the oxalate oxidation treatment are washed with water, dried, and then roasted. By undergoing this roasting treatment, scandium can be recovered as scandium oxide.
特に、本実施の形態においては、上述したシュウ酸化処理における反応温度を特定の範囲として反応を生じさせているため、生成するシュウ酸スカンジウムの不純物品位が有効に低減されているとともに、その不純物品位のばらつきも抑えられている。したがって、そのようなシュウ酸スカンジウムを焙焼することで、不純物品位が低減され、かつ、不純物品位のばらつきが抑えられた、高純度なスカンジウムを含有する酸化スカンジウムを得ることができる。
In particular, in the present embodiment, since the reaction is caused by setting the reaction temperature in the above-mentioned oxalic acid oxidation treatment within a specific range, the impurity grade of the scandium oxalate to be produced is effectively reduced, and the impurity grade is reduced. Variations are also suppressed. Therefore, by roasting such scandium oxalate, it is possible to obtain scandium oxide containing high-purity scandium in which the impurity grade is reduced and the variation in the impurity grade is suppressed.
焙焼処理の条件としては、特に限定されないが、例えば管状炉に入れて約９００℃で２時間程度加熱すればよい。なお、工業的には、ロータリーキルン等の連続炉を用いることによって、乾燥と焙焼とを同じ装置で行うことができるため好ましい。
The conditions of the roasting treatment are not particularly limited, but for example, it may be placed in a tube furnace and heated at about 900 ° C. for about 2 hours. Industrially, it is preferable to use a continuous furnace such as a rotary kiln because drying and roasting can be performed by the same apparatus.
以下、本発明の実施例及び比較例を示して、本発明についてより具体的に説明する。なお、本発明は以下の実施例に何ら限定されない。
Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples of the present invention. The present invention is not limited to the following examples.
（ニッケル酸化鉱石の湿式製錬プロセス）
オートクレーブを用いてニッケル酸化鉱石を硫酸で浸出し、得られた浸出液に消石灰を添加して中和した。次いで、得られた中和後液に硫化剤を添加して硫化反応を生じさせ、ニッケルやコバルト等を硫化物として分離し、スカンジウムを含有する硫化後液を得た。 (Hydrometallurgy process of nickel oxide ore)
Nickel oxide ore was leached with sulfuric acid using an autoclave, and slaked lime was added to the obtained leachate to neutralize it. Then, a sulfurizing agent was added to the obtained neutralized liquid to cause a sulfurization reaction, and nickel, cobalt and the like were separated as sulfides to obtain a scandium-containing post-sulfurized liquid.
オートクレーブを用いてニッケル酸化鉱石を硫酸で浸出し、得られた浸出液に消石灰を添加して中和した。次いで、得られた中和後液に硫化剤を添加して硫化反応を生じさせ、ニッケルやコバルト等を硫化物として分離し、スカンジウムを含有する硫化後液を得た。 (Hydrometallurgy process of nickel oxide ore)
Nickel oxide ore was leached with sulfuric acid using an autoclave, and slaked lime was added to the obtained leachate to neutralize it. Then, a sulfurizing agent was added to the obtained neutralized liquid to cause a sulfurization reaction, and nickel, cobalt and the like were separated as sulfides to obtain a scandium-containing post-sulfurized liquid.
（イオン交換処理、中和処理）
次に、得られた硫化後液に対してキレート樹脂を用いたイオン交換処理に付し、溶液中の不純物を分離するとともに、キレート樹脂から溶離したスカンジウムを含む溶離液（スカンジウム溶離液）を得た。その後、スカンジウム溶離液に対して中和剤を添加して、水酸化スカンジウムの沈殿物を生成させた。 (Ion exchange treatment, neutralization treatment)
Next, the obtained post-sulfurized solution is subjected to ion exchange treatment using a chelate resin to separate impurities in the solution, and an eluent containing scandium eluted from the chelate resin (scandium eluent) is obtained. rice field. Then, a neutralizing agent was added to the scandium eluent to form a scandium hydroxide precipitate.
次に、得られた硫化後液に対してキレート樹脂を用いたイオン交換処理に付し、溶液中の不純物を分離するとともに、キレート樹脂から溶離したスカンジウムを含む溶離液（スカンジウム溶離液）を得た。その後、スカンジウム溶離液に対して中和剤を添加して、水酸化スカンジウムの沈殿物を生成させた。 (Ion exchange treatment, neutralization treatment)
Next, the obtained post-sulfurized solution is subjected to ion exchange treatment using a chelate resin to separate impurities in the solution, and an eluent containing scandium eluted from the chelate resin (scandium eluent) is obtained. rice field. Then, a neutralizing agent was added to the scandium eluent to form a scandium hydroxide precipitate.
（溶媒抽出処理）
次に、水酸化スカンジウムの沈殿物に硫酸を添加して再度溶解して溶解液（スカンジウム溶解液）とし、このスカンジウム溶解液に対してアミン系抽出剤を用いた溶媒抽出処理に付し、抽残液として、大部分の不純物を除去して精製し並びにスカンジウムを濃縮させたスカンジウム溶液（スカンジウム含有溶液）を得た。 (Solvent extraction treatment)
Next, sulfuric acid is added to the precipitate of scandium hydroxide and dissolved again to obtain a solution (scandium solution), which is then subjected to solvent extraction treatment using an amine-based extractant and extracted. As the residual liquid, most of the impurities were removed and purified, and a scandium solution (scandium-containing solution) in which scandium was concentrated was obtained.
次に、水酸化スカンジウムの沈殿物に硫酸を添加して再度溶解して溶解液（スカンジウム溶解液）とし、このスカンジウム溶解液に対してアミン系抽出剤を用いた溶媒抽出処理に付し、抽残液として、大部分の不純物を除去して精製し並びにスカンジウムを濃縮させたスカンジウム溶液（スカンジウム含有溶液）を得た。 (Solvent extraction treatment)
Next, sulfuric acid is added to the precipitate of scandium hydroxide and dissolved again to obtain a solution (scandium solution), which is then subjected to solvent extraction treatment using an amine-based extractant and extracted. As the residual liquid, most of the impurities were removed and purified, and a scandium solution (scandium-containing solution) in which scandium was concentrated was obtained.
（シュウ酸化処理）
次に、得られたスカンジウム含有溶液を用いて、溶液中のスカンジウムをシュウ酸塩とするシュウ酸化処理を行った。 (Shu oxidation treatment)
Next, using the obtained scandium-containing solution, a oxalate oxidation treatment was performed using scandium in the solution as an oxalate.
次に、得られたスカンジウム含有溶液を用いて、溶液中のスカンジウムをシュウ酸塩とするシュウ酸化処理を行った。 (Shu oxidation treatment)
Next, using the obtained scandium-containing solution, a oxalate oxidation treatment was performed using scandium in the solution as an oxalate.
具体的には、スカンジウム含有溶液に硫酸を添加してｐＨが０．２８となるように調整し、さらに溶液中のスカンジウム濃度が４．５ｇ／Ｌ程度になるまでに水を加えて希釈して、シュウ酸化始液を調製した。下記表１、２に示す条件下での試験１回につき５００ｍｌのシュウ酸化始液を準備した。なお、ｐＨ調整はそれぞれの試験の反応時の温度（反応温度）と同じ温度条件下で行った。当該スカンジウム含有溶液の酸化還元電位（ＯＲＰ）は、銀／塩化銀電極を標準電極とする値で５００ｍＶ～５６０ｍＶであった。
Specifically, sulfuric acid is added to the scandium-containing solution to adjust the pH to 0.28, and water is further added until the scandium concentration in the solution reaches about 4.5 g / L to dilute the solution. , Scandium oxidation starting solution was prepared. 500 ml of Shu oxidation starting solution was prepared for each test under the conditions shown in Tables 1 and 2 below. The pH was adjusted under the same temperature conditions as the reaction temperature (reaction temperature) of each test. The redox potential (ORP) of the scandium-containing solution was 500 mV to 560 mV with a silver / silver chloride electrode as a standard electrode.
また、シュウ酸化処理に用いるシュウ酸溶液として、液量１Ｌあたりシュウ酸１００ｇを溶解した溶液を準備した。
Further, as the oxalic acid solution used for the oxalic acid treatment, a solution in which 100 g of oxalic acid was dissolved per 1 L of the liquid volume was prepared.
シュウ酸化処理においては、各試験で用いるシュウ酸化始液に含まれるスカンジウムに対して２．７当量となる１８３ｍｌ、もしくは５．１当量となる３４４ｍｌの量のシュウ酸溶液を容器に収容し、そのシュウ酸溶液の中に、シュウ酸化始液（スカンジウム含有溶液）を２．３ｍｌ／ｍｉｎの流量で添加して反応させた。また、その反応時における温度（反応温度）は、試験ごとに、室温（２３℃）、３０℃、３５℃、４２℃、及び５０℃のいずれかで設定し、シュウ酸溶液に対するシュウ酸化始液の添加を開始してから１時間の撹拌終了まで、その温度を維持した。
In the oxalic acid treatment, a oxalic acid solution in an amount of 183 ml, which is 2.7 equivalents, or 344 ml, which is 5.1 equivalents, with respect to scandium contained in the scandium used in each test is contained in a container. An initial solution of shu oxidation (scandium-containing solution) was added to the oxalic acid solution at a flow rate of 2.3 ml / min and reacted. The temperature (reaction temperature) at the time of the reaction is set at room temperature (23 ° C.), 30 ° C., 35 ° C., 42 ° C., or 50 ° C. for each test, and the oxalic acid solution is used as the starting solution for oxalic acid. The temperature was maintained from the start of addition to the end of stirring for 1 hour.
下記表１に、各試験におけるシュウ酸溶液の当量及び反応温度の試験条件と、シュウ酸化処理に供したスカンジウム含有溶液（シュウ酸化始液）に含まれる金属成分の濃度の分析結果を示す。表１に示すように、スカンジウム含有溶液には、種々の不純物金属元素が含まれていることがわかる。
Table 1 below shows the test conditions for the equivalent of the oxalic acid solution and the reaction temperature in each test, and the analysis results of the concentration of the metal component contained in the scandium-containing solution (starting solution of oxalic acid) used for the oxalic acid treatment. As shown in Table 1, it can be seen that the scandium-containing solution contains various impurity metal elements.
撹拌終了後、静置して、晶析したシュウ酸スカンジウムを沈澱させた。次いで、容器内の液が残り１５０ｍｌになるまで上澄みを取り、１５０ｍｌの純水を投入して撹拌洗浄する洗浄操作を２回繰り返した。なお、洗浄操作はそれぞれ、シュウ酸添加時の温度（反応温度）と同じ温度条件下で行った。
After the stirring was completed, the mixture was allowed to stand to precipitate the crystallized scandium oxalate. Then, the supernatant was taken until the remaining liquid in the container was 150 ml, and the washing operation of adding 150 ml of pure water and stirring and washing was repeated twice. Each cleaning operation was performed under the same temperature conditions as the temperature at the time of adding oxalic acid (reaction temperature).
次に、洗浄後、吸引濾過装置と孔径０．４５μｍのメンブレンフィルターを使用して全量濾過を行い、シュウ酸スカンジウムの結晶を分離した。さらに、分離した結晶を約５０ｇ／Ｌのスラリー濃度になるように１４０ｍｌの純水中に投入してレパルプ洗浄することを２回繰り返した。
Next, after washing, the whole amount was filtered using a suction filtration device and a membrane filter having a pore size of 0.45 μm, and scandium oxalate crystals were separated. Further, the separated crystals were put into 140 ml of pure water so as to have a slurry concentration of about 50 g / L, and repulp washing was repeated twice.
レパルプ洗浄後、同じ吸引濾過装置とメンブレンフィルターを用いて全量濾過を行い、シュウ酸スカンジウムの結晶を回収した。その後、得られたシュウ酸スカンジウムの結晶を温度１０５℃の大気乾燥機で一晩乾燥させ、乾燥した結晶をＩＣＰ原子吸光光度法により分析し、不純物品位を確認した。
After washing the repulp, the whole amount was filtered using the same suction filtration device and membrane filter, and scandium oxalate crystals were recovered. Then, the obtained scandium oxalate crystals were dried overnight in an air dryer at a temperature of 105 ° C., and the dried crystals were analyzed by the ICP atomic absorption spectrophotometric method to confirm the impurity grade.
下記表２に、試験例１～試験例１６において得られたシュウ酸スカンジウムの不純物品位の分析結果を示す。
Table 2 below shows the analysis results of the impurity grade of scandium oxalate obtained in Test Examples 1 to 16.
表２に示すように、シュウ酸化処理に際しての反応温度を２０℃以上３５℃以下の範囲とした試験例１～試験例１０では、反応温度を３５℃よりも高い条件とした試験例１１～１６と比べて、不純物品位を有効に低減できたとともに、同じ反応温度条件下においてシュウ酸当量等の他の条件で違いがあっても、不純物品位のばらつきを抑えることができた。試験例１１～１６では、不純物品位の低減効果が劣るものであっただけでなく、同じ反応温度条件下においてシュウ酸当量の条件の違いによって、不純物品位のばらつきが生じてしまった。
As shown in Table 2, in Test Examples 1 to 10 in which the reaction temperature during the oxalis oxidation treatment was in the range of 20 ° C. or higher and 35 ° C. or lower, Test Examples 11 to 16 in which the reaction temperature was higher than 35 ° C. In addition to being able to effectively reduce the impurity grade, it was possible to suppress variations in the impurity grade even if there were differences in other conditions such as oxalic acid equivalent under the same reaction temperature conditions. In Test Examples 11 to 16, not only the effect of reducing the impurity grade was inferior, but also the impurity grade varied due to the difference in the oxalic acid equivalent conditions under the same reaction temperature conditions.
得られたシュウ酸スカンジウムに含まれる不純物品位のばらつきを確認するために、下記表３に、試験例１～試験例１６の全１６の例において、不純物金属元素として特に、Ｎｉ、Ｍｎ、Ｆｅ、及びＡｌの品位について着目したときの、反応温度を及びシュウ酸当量と不純物品位とを関係をまとめた。また、図４～図６は、下記表３に基づき、それぞれ、Ｎｉ品位（図４）、Ｍｎ品位（図５）、Ｆｅ品位（図６）と反応温度との関係を、２種類（２．７当量、５．１当量）のシュウ酸当量で比較したときのグラフ図である。
In order to confirm the variation in the impurity grade contained in the obtained scandium oxalate, in Table 3 below, in all 16 examples of Test Examples 1 to 16, the impurity metal elements were particularly Ni, Mn, Fe, and so on. The relationship between the reaction temperature, the oxalic acid equivalent, and the impurity grade when focusing on the grade of Al was summarized. Further, FIGS. 4 to 6 show two types (2.) of the relationship between the Ni grade (FIG. 4), the Mn grade (FIG. 5), the Fe grade (FIG. 6) and the reaction temperature, respectively, based on Table 3 below. It is a graph figure when comparing with the oxalic acid equivalent of 7 equivalents, 5.1 equivalents).
図４～図６のグラフ図からもわかるように、反応温度が２０℃以上３５℃以下の範囲でシュウ酸化処理を行った場合には、シュウ酸当量がいずれの条件であっても不純物品にばらつきは生じず低品位であった。一方で、反応温度が３５℃を超える条件では、シュウ酸当量の違いによって、不純物品位のばらつきが生じていることが明確にわかる。
As can be seen from the graphs of FIGS. 4 to 6, when the oxalic acid treatment is performed in the range of the reaction temperature of 20 ° C. or higher and 35 ° C. or lower, the oxalic acid equivalent becomes an impurity product regardless of the conditions. There was no variation and the quality was low. On the other hand, under the condition that the reaction temperature exceeds 35 ° C., it can be clearly seen that the impurity grade varies due to the difference in oxalic acid equivalent.
Claims (5)
- スカンジウムと、不純物金属元素とを含有する酸性溶液（スカンジウム含有溶液）からスカンジウムを回収する方法であって、
容器に収容したシュウ酸溶液に前記スカンジウム含有溶液を添加する逆添加法によりシュウ酸化処理を行い、シュウ酸スカンジウムを得る工程を含み、
前記工程では、前記シュウ酸化処理における反応温度を２０℃以上３５℃以下とする、
スカンジウムの回収方法。 A method for recovering scandium from an acidic solution (scandium-containing solution) containing scandium and an impurity metal element.
Including a step of obtaining scandium oxalate by performing a oxalic acid treatment by a reverse addition method in which the scandium-containing solution is added to the oxalic acid solution contained in a container.
In the step, the reaction temperature in the sucrose oxidation treatment is set to 20 ° C. or higher and 35 ° C. or lower.
Scandium recovery method. - 前記スカンジウム含有溶液は、前記不純物金属元素として、少なくとも、鉄、ニッケル、及びマンガンからなる群から選ばれる１種以上を含有する、
請求項１に記載のスカンジウムの回収方法。 The scandium-containing solution contains at least one selected from the group consisting of iron, nickel, and manganese as the impurity metal element.
The scandium recovery method according to claim 1. - 前記スカンジウム含有溶液は、ニッケル酸化鉱石を硫酸により浸出して得られた浸出液に硫化剤を添加して生成する硫化物を分離した後の溶液である、
請求項１又は２に記載のスカンジウムの回収方法。 The scandium-containing solution is a solution after separating the sulfide produced by adding a sulfide agent to the leachate obtained by leaching nickel oxide ore with sulfuric acid.
The scandium recovery method according to claim 1 or 2. - 前記工程では、前記スカンジウム含有溶液のｐＨを－０．５以上１．０未満の範囲に調整して前記シュウ酸化処理を行う、
請求項１乃至３のいずれかに記載のスカンジウムの回収方法。 In the step, the pH of the scandium-containing solution is adjusted to a range of −0.5 or more and less than 1.0, and the shu oxidation treatment is performed.
The scandium recovery method according to any one of claims 1 to 3. - 前記シュウ酸化処理に供する前記スカンジウム含有溶液には、酸化剤を添加しない、
請求項１乃至４のいずれかに記載のスカンジウムの回収方法。 No oxidizing agent is added to the scandium-containing solution to be subjected to the shu oxidation treatment.
The scandium recovery method according to any one of claims 1 to 4.
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