NO346383B1 - Method for converting a waste material from sulphide ore based nickel refining into nickel pig iron - Google Patents
Method for converting a waste material from sulphide ore based nickel refining into nickel pig iron Download PDFInfo
- Publication number
- NO346383B1 NO346383B1 NO20170743A NO20170743A NO346383B1 NO 346383 B1 NO346383 B1 NO 346383B1 NO 20170743 A NO20170743 A NO 20170743A NO 20170743 A NO20170743 A NO 20170743A NO 346383 B1 NO346383 B1 NO 346383B1
- Authority
- NO
- Norway
- Prior art keywords
- nickel
- waste material
- mixture
- pellets
- smelting
- Prior art date
Links
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 title claims description 129
- 239000002699 waste material Substances 0.000 title claims description 81
- 229910052759 nickel Inorganic materials 0.000 title claims description 64
- 238000000034 method Methods 0.000 title claims description 53
- 229910001356 Nickel pig iron Inorganic materials 0.000 title claims description 28
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 title claims description 6
- 238000007670 refining Methods 0.000 title claims description 5
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 130
- ODINCKMPIJJUCX-UHFFFAOYSA-N Calcium oxide Chemical compound [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 claims description 85
- 239000000203 mixture Substances 0.000 claims description 74
- 239000008188 pellet Substances 0.000 claims description 64
- 238000003723 Smelting Methods 0.000 claims description 50
- 239000002893 slag Substances 0.000 claims description 49
- 239000000292 calcium oxide Substances 0.000 claims description 43
- 235000012255 calcium oxide Nutrition 0.000 claims description 43
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 38
- 229910052799 carbon Inorganic materials 0.000 claims description 35
- 239000000463 material Substances 0.000 claims description 25
- 238000010438 heat treatment Methods 0.000 claims description 23
- 238000002156 mixing Methods 0.000 claims description 21
- 150000001875 compounds Chemical class 0.000 claims description 18
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 18
- 229910052785 arsenic Inorganic materials 0.000 claims description 17
- 239000000460 chlorine Substances 0.000 claims description 17
- 238000002844 melting Methods 0.000 claims description 16
- 230000008018 melting Effects 0.000 claims description 16
- 239000007787 solid Substances 0.000 claims description 16
- RQNWIZPPADIBDY-UHFFFAOYSA-N arsenic atom Chemical compound [As] RQNWIZPPADIBDY-UHFFFAOYSA-N 0.000 claims description 14
- 229910052801 chlorine Inorganic materials 0.000 claims description 14
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 12
- 229910052751 metal Inorganic materials 0.000 claims description 12
- 239000002184 metal Substances 0.000 claims description 12
- 229910052760 oxygen Inorganic materials 0.000 claims description 12
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 11
- 239000003517 fume Substances 0.000 claims description 11
- 239000001301 oxygen Substances 0.000 claims description 11
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 claims description 10
- 229910021586 Nickel(II) chloride Inorganic materials 0.000 claims description 9
- 239000007789 gas Substances 0.000 claims description 9
- QMMRZOWCJAIUJA-UHFFFAOYSA-L nickel dichloride Chemical compound Cl[Ni]Cl QMMRZOWCJAIUJA-UHFFFAOYSA-L 0.000 claims description 9
- 238000003756 stirring Methods 0.000 claims description 9
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 claims description 8
- 239000005864 Sulphur Substances 0.000 claims description 8
- 229910002588 FeOOH Inorganic materials 0.000 claims description 7
- 238000005453 pelletization Methods 0.000 claims description 7
- KZBUYRJDOAKODT-UHFFFAOYSA-N Chlorine Chemical compound ClCl KZBUYRJDOAKODT-UHFFFAOYSA-N 0.000 claims description 6
- 238000005266 casting Methods 0.000 claims description 6
- 238000001035 drying Methods 0.000 claims description 6
- FLTRNWIFKITPIO-UHFFFAOYSA-N iron;trihydrate Chemical compound O.O.O.[Fe] FLTRNWIFKITPIO-UHFFFAOYSA-N 0.000 claims description 6
- 238000010079 rubber tapping Methods 0.000 claims description 6
- 239000000377 silicon dioxide Substances 0.000 claims description 6
- 229910052681 coesite Inorganic materials 0.000 claims description 5
- 229910052906 cristobalite Inorganic materials 0.000 claims description 5
- 239000010881 fly ash Substances 0.000 claims description 5
- 235000012239 silicon dioxide Nutrition 0.000 claims description 5
- 229910052682 stishovite Inorganic materials 0.000 claims description 5
- 229910052905 tridymite Inorganic materials 0.000 claims description 5
- 238000013022 venting Methods 0.000 claims description 4
- 238000002347 injection Methods 0.000 claims description 3
- 239000007924 injection Substances 0.000 claims description 3
- 229910001338 liquidmetal Inorganic materials 0.000 claims description 2
- 239000011819 refractory material Substances 0.000 claims description 2
- 238000004056 waste incineration Methods 0.000 claims description 2
- 229910052742 iron Inorganic materials 0.000 description 51
- 238000004519 manufacturing process Methods 0.000 description 30
- 239000003638 chemical reducing agent Substances 0.000 description 14
- 239000010802 sludge Substances 0.000 description 14
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N iron oxide Inorganic materials [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 13
- 230000002829 reductive effect Effects 0.000 description 13
- 229940124024 weight reducing agent Drugs 0.000 description 13
- 238000006722 reduction reaction Methods 0.000 description 12
- 229910000863 Ferronickel Inorganic materials 0.000 description 10
- 229910001030 Iron–nickel alloy Inorganic materials 0.000 description 10
- 230000008901 benefit Effects 0.000 description 10
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 10
- 238000001354 calcination Methods 0.000 description 9
- 238000001556 precipitation Methods 0.000 description 9
- 229910045601 alloy Inorganic materials 0.000 description 8
- 239000000956 alloy Substances 0.000 description 8
- 239000000843 powder Substances 0.000 description 8
- 239000000047 product Substances 0.000 description 8
- SZVJSHCCFOBDDC-UHFFFAOYSA-N ferrosoferric oxide Chemical compound O=[Fe]O[Fe]O[Fe]=O SZVJSHCCFOBDDC-UHFFFAOYSA-N 0.000 description 7
- 239000000155 melt Substances 0.000 description 7
- 229910002555 FeNi Inorganic materials 0.000 description 6
- 229910000480 nickel oxide Inorganic materials 0.000 description 6
- GNRSAWUEBMWBQH-UHFFFAOYSA-N oxonickel Chemical compound [Ni]=O GNRSAWUEBMWBQH-UHFFFAOYSA-N 0.000 description 6
- 239000012071 phase Substances 0.000 description 6
- 239000002994 raw material Substances 0.000 description 6
- WWNBZGLDODTKEM-UHFFFAOYSA-N sulfanylidenenickel Chemical compound [Ni]=S WWNBZGLDODTKEM-UHFFFAOYSA-N 0.000 description 6
- 238000006243 chemical reaction Methods 0.000 description 5
- 239000003795 chemical substances by application Substances 0.000 description 5
- 229910052500 inorganic mineral Inorganic materials 0.000 description 5
- QJSRJXPVIMXHBW-UHFFFAOYSA-J iron(2+);nickel(2+);tetrahydroxide Chemical compound [OH-].[OH-].[OH-].[OH-].[Fe+2].[Ni+2] QJSRJXPVIMXHBW-UHFFFAOYSA-J 0.000 description 5
- 239000010808 liquid waste Substances 0.000 description 5
- 235000010755 mineral Nutrition 0.000 description 5
- 239000011707 mineral Substances 0.000 description 5
- 239000002245 particle Substances 0.000 description 5
- 239000000126 substance Substances 0.000 description 5
- YLQBMQCUIZJEEH-UHFFFAOYSA-N Furan Chemical compound C=1C=COC=1 YLQBMQCUIZJEEH-UHFFFAOYSA-N 0.000 description 4
- 229910000413 arsenic oxide Inorganic materials 0.000 description 4
- 229910052804 chromium Inorganic materials 0.000 description 4
- 239000011651 chromium Substances 0.000 description 4
- 229910052802 copper Inorganic materials 0.000 description 4
- 239000010949 copper Substances 0.000 description 4
- 230000007613 environmental effect Effects 0.000 description 4
- 239000012535 impurity Substances 0.000 description 4
- 235000013980 iron oxide Nutrition 0.000 description 4
- 239000010935 stainless steel Substances 0.000 description 4
- 229910001220 stainless steel Inorganic materials 0.000 description 4
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 3
- 229910001021 Ferroalloy Inorganic materials 0.000 description 3
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- 229910000756 V alloy Inorganic materials 0.000 description 3
- 230000002378 acidificating effect Effects 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 3
- 229910052598 goethite Inorganic materials 0.000 description 3
- 239000008187 granular material Substances 0.000 description 3
- 239000010439 graphite Substances 0.000 description 3
- 229910002804 graphite Inorganic materials 0.000 description 3
- AEIXRCIKZIZYPM-UHFFFAOYSA-M hydroxy(oxo)iron Chemical compound [O][Fe]O AEIXRCIKZIZYPM-UHFFFAOYSA-M 0.000 description 3
- 239000007788 liquid Substances 0.000 description 3
- 230000003472 neutralizing effect Effects 0.000 description 3
- 230000003287 optical effect Effects 0.000 description 3
- NDLPOXTZKUMGOV-UHFFFAOYSA-N oxo(oxoferriooxy)iron hydrate Chemical compound O.O=[Fe]O[Fe]=O NDLPOXTZKUMGOV-UHFFFAOYSA-N 0.000 description 3
- 230000001681 protective effect Effects 0.000 description 3
- 229910052717 sulfur Inorganic materials 0.000 description 3
- 229910000640 Fe alloy Inorganic materials 0.000 description 2
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 description 2
- VTLYFUHAOXGGBS-UHFFFAOYSA-N Fe3+ Chemical compound [Fe+3] VTLYFUHAOXGGBS-UHFFFAOYSA-N 0.000 description 2
- CPLXHLVBOLITMK-UHFFFAOYSA-N Magnesium oxide Chemical compound [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 2
- IKWTVSLWAPBBKU-UHFFFAOYSA-N a1010_sial Chemical compound O=[As]O[As]=O IKWTVSLWAPBBKU-UHFFFAOYSA-N 0.000 description 2
- 239000002253 acid Substances 0.000 description 2
- 229960002594 arsenic trioxide Drugs 0.000 description 2
- 239000002956 ash Substances 0.000 description 2
- 239000006227 byproduct 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
- 238000001816 cooling Methods 0.000 description 2
- 230000008021 deposition Effects 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- 229960004887 ferric hydroxide Drugs 0.000 description 2
- 238000001914 filtration Methods 0.000 description 2
- 230000006698 induction Effects 0.000 description 2
- UGKDIUIOSMUOAW-UHFFFAOYSA-N iron nickel Chemical compound [Fe].[Ni] UGKDIUIOSMUOAW-UHFFFAOYSA-N 0.000 description 2
- DMTIXTXDJGWVCO-UHFFFAOYSA-N iron(2+) nickel(2+) oxygen(2-) Chemical compound [O--].[O--].[Fe++].[Ni++] DMTIXTXDJGWVCO-UHFFFAOYSA-N 0.000 description 2
- VBMVTYDPPZVILR-UHFFFAOYSA-N iron(2+);oxygen(2-) Chemical class [O-2].[Fe+2] VBMVTYDPPZVILR-UHFFFAOYSA-N 0.000 description 2
- IEECXTSVVFWGSE-UHFFFAOYSA-M iron(3+);oxygen(2-);hydroxide Chemical compound [OH-].[O-2].[Fe+3] IEECXTSVVFWGSE-UHFFFAOYSA-M 0.000 description 2
- 238000002386 leaching Methods 0.000 description 2
- 238000010907 mechanical stirring Methods 0.000 description 2
- 238000000465 moulding Methods 0.000 description 2
- 229910000008 nickel(II) carbonate Inorganic materials 0.000 description 2
- 229910052954 pentlandite Inorganic materials 0.000 description 2
- 239000002244 precipitate Substances 0.000 description 2
- 238000004064 recycling Methods 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 239000002910 solid waste Substances 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- 238000009628 steelmaking Methods 0.000 description 2
- 238000005406 washing Methods 0.000 description 2
- KVGZZAHHUNAVKZ-UHFFFAOYSA-N 1,4-Dioxin Chemical compound O1C=COC=C1 KVGZZAHHUNAVKZ-UHFFFAOYSA-N 0.000 description 1
- 229910000851 Alloy steel Inorganic materials 0.000 description 1
- 229910000967 As alloy Inorganic materials 0.000 description 1
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 1
- 229910000570 Cupronickel Inorganic materials 0.000 description 1
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 1
- -1 FeO Chemical compound 0.000 description 1
- 229910021577 Iron(II) chloride Inorganic materials 0.000 description 1
- 229910000805 Pig iron Inorganic materials 0.000 description 1
- 235000011941 Tilia x europaea Nutrition 0.000 description 1
- 239000006096 absorbing agent Substances 0.000 description 1
- 150000007513 acids Chemical class 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 239000004566 building material Substances 0.000 description 1
- BRPQOXSCLDDYGP-UHFFFAOYSA-N calcium oxide Chemical compound [O-2].[Ca+2] BRPQOXSCLDDYGP-UHFFFAOYSA-N 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 239000004568 cement Substances 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 239000004035 construction material Substances 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 238000010924 continuous production Methods 0.000 description 1
- BWFPGXWASODCHM-UHFFFAOYSA-N copper monosulfide Chemical class [Cu]=S BWFPGXWASODCHM-UHFFFAOYSA-N 0.000 description 1
- YOCUPQPZWBBYIX-UHFFFAOYSA-N copper nickel Chemical compound [Ni].[Cu] YOCUPQPZWBBYIX-UHFFFAOYSA-N 0.000 description 1
- 239000010432 diamond Substances 0.000 description 1
- 150000002013 dioxins Chemical class 0.000 description 1
- 229910001882 dioxygen Inorganic materials 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 239000000295 fuel oil Substances 0.000 description 1
- 125000002541 furyl group Chemical group 0.000 description 1
- 239000002920 hazardous waste Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 1
- 235000000396 iron Nutrition 0.000 description 1
- NMCUIPGRVMDVDB-UHFFFAOYSA-L iron dichloride Chemical compound Cl[Fe]Cl NMCUIPGRVMDVDB-UHFFFAOYSA-L 0.000 description 1
- ILKIXSABKPWMHU-UHFFFAOYSA-N iron;sulfanylidenenickel Chemical compound [Fe].[Ni]=S ILKIXSABKPWMHU-UHFFFAOYSA-N 0.000 description 1
- 239000004571 lime Substances 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- VASIZKWUTCETSD-UHFFFAOYSA-N manganese(II) oxide Inorganic materials [Mn]=O VASIZKWUTCETSD-UHFFFAOYSA-N 0.000 description 1
- 238000006386 neutralization reaction Methods 0.000 description 1
- ZULUUIKRFGGGTL-UHFFFAOYSA-L nickel(ii) carbonate Chemical compound [Ni+2].[O-]C([O-])=O ZULUUIKRFGGGTL-UHFFFAOYSA-L 0.000 description 1
- 150000002894 organic compounds Chemical class 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 239000011505 plaster Substances 0.000 description 1
- 231100000614 poison Toxicity 0.000 description 1
- 230000007096 poisonous effect Effects 0.000 description 1
- 230000001376 precipitating effect Effects 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000010298 pulverizing process Methods 0.000 description 1
- 238000011946 reduction process Methods 0.000 description 1
- 230000035939 shock Effects 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
- 239000002002 slurry Substances 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 238000012795 verification Methods 0.000 description 1
- 239000002351 wastewater Substances 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
Classifications
-
- 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
- C22B23/00—Obtaining nickel or cobalt
- C22B23/02—Obtaining nickel or cobalt by dry processes
- C22B23/023—Obtaining nickel or cobalt by dry processes with formation of ferro-nickel or ferro-cobalt
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B3/00—General features in the manufacture of pig-iron
- C21B3/04—Recovery of by-products, e.g. slag
-
- 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
- C22B7/00—Working up raw materials other than ores, e.g. scrap, to produce non-ferrous metals and compounds thereof; Methods of a general interest or applied to the winning of more than two metals
- C22B7/04—Working-up slag
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
-
- 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
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
Description
The present invention relates to a method for converting a waste material from sulphide ore based nickel production to a ferroalloy product.
Background
A major nickel source on earth is nickel ores containing pentlandite, an iron-nickel sulphide mineral of chemical formula (Fe, Ni)9S8. Pentlandite containing ores are also known as sulphide nickel ores and is usually being treated by pyrometallurgical techniques to form a nickel matte having an increased nickel content and reduced iron content (and other impurities) before being utilised as raw material in nickel refining. However, the nickel matte still contains a significant residue of iron, making iron the most significant impurity (in tonnage) in nickel sulphide ore based production of nickel.
At the Glencore Nikkelverk As in Kristiansand, Norway, the iron content of the nickel matte is removed by a chlorine leaching process forming a solid residue containing the iron and other hydrometallurgical residues which are sent to deposition halls excavated in the mountain ground. The chlorine leaching process converts the iron content in the nickel matte to an aqueous solution of ferrous iron chloride. By simultaneous addition of chlorine gas and nickel carbonate to the ferrous iron chloride solution, the iron content may be precipitated as ferric hydroxide, the overall chemical reaction is:
2 FeCl2 + Cl2(g) 3 H2O 3 NiCO3(s) ↔ 2 Fe(OH)3(s) 3 NiCl2 + 3 CO2(g)
The solid residues form the precipitation step are presently being treated as an environmental hazardous waste material which need to be deposited in deposits equipped with capability of collecting and treating leakage water from the deposit. At the Xstrata Nikkelverk AS the amount of waste material for deposition is in the order of 20000 tonnes per year – an amount which clearly poses challenges related to costs, environmental issues and safe handling of the waste material and its deposits.
It is thus desirable, both from an environmental and a cost perspective to find a method for recycling the mineral content of the waste material and convert it to a valuable product.
Prior art
From CN 101463 402, it is known a method for producing nickel chilled pig iron by using nickel ore and stainless by-product, the method includes steps of spraying nickel ore of 20 wt% or less, stainless by-product of 50 wt% or more, reductant of 7-13 wt%, slag making material of 7-12 wt% and recycle slag of 10 wt% or less into a SAF electric stove to melt in the SAF stove.
From WO 2008/140265, it is known a method for retrieving iron and nickel content in a waste fraction from acid washing step during manufacturing of diamonds by manufacturing a Fe/Ni-containing material having a low content of sulphur (S) from an Fe/Ni/SO4-containing liquid waste, a ferronickel mass using the Fe/Ni-containing material, and a method of manufacturing the ferronickel mass. The method of manufacturing an Fe/Ni-containing material from an Fe/Ni-containing liquid waste includes: removing SO4 from an Fe/Ni/SO4-containing liquid waste by adding an SO4 neutralizing agent to the liquid waste so that pH of the liquid waste can be maintained to a pH level of 0.5 to 2.5; precipitating Fe and Ni in the form of hydroxide [(Ni,Fe)(OH)] by adding NaOH to the SO4-free solution; washing the precipitate with water; and manufacturing an Ni/Fe-containing material by filtering and drying the washed Ni/Fe-containing sludge. The method of manufacturing a Fe/Ni-containing material may be useful to suitably apply to the field of recycling of waste acids since a Fe/Ni-containing pellet and a high purity plaster are recovered as the stainless steel material from the waste water at the same time.
From WO 2008/075879 it is known a method for manufacturing a raw material for stainless steel using a sludge containing Fe, Ni and Cl. The method comprises: neutralizing a sludge containing Fe, Ni and Cl by adding calcium hydroxide to the sludge at a molar ratio (moles of added calcium hydroxide/ moles of existing Cl) of 0.5-1.5; filtering, drying and pulverizing the sludge prepared in the neutralization operation; mixing 5-15 parts by weight of a reducing agent with pulverized sludge, based on 100 parts by weight of the dried powder; adding 5-15 parts by weight of a cement binder to 100 parts by weight of the mixture powder and forming the mixture powder into mass; and curing the formed mass. The raw material for stainless steel may be used since raw material may be prepared without completely removing Cl from the sludge, and therefore there is no problem about environmental pollutions caused by the Cl evaporation.
From CN 104178 624 it is known a method for preparing ferronickel by using red mud and laterite-nickel ore. According to the method, iron-nickel reduction products in the red mud and the laterite-nickel ore are directly utilized and low-cost ferronickel can be provided for stainless steel smelting production, ferroalloy casting and alloy steel production. The laterite-nickel ore also contains a little of chromium, and in the production method disclosed by the invention, chromium enters the iron-nickel alloy, so that beneficial chemical components of the ironnickel alloy are enriched. The contained iron-nickel alloy produced by the method disclosed by the invention is iron-nickel alloy with low P and S content.
From CN 104120 209 it is known a method for producing nickel-containing molten iron by smelting and reducing liquid-state nickel slag. The method comprises the following steps: feeding liquid-state nickel slag and a reducing agent into a smelting and reducing furnace according to a predetermined mass ratio; enabling the liquidstate nickel slag and the reducing agent to react in the smelting and reducing furnace, and stirring at the same time; and generating nickel-containing molten iron and smelting slag after the reaction is ended, wherein the nickel-containing molten iron is at the lower layer of the smelting and reducing furnace, and the smelting slag is at the upper layer of the nickel-containing molten iron. The nickel-containing molten iron can be directly used for steelmaking, and the obtained smelting slag can be used for producing building materials. The method for producing the nickelcontaining molten iron by smelting and reducing liquid-state nickel slag, which is provided by the invention can realize energy-saving production, comprehensive utilization of resources and good economic benefits.
From CN 101538 631 it is known a process and a device for smelting ferronickel and nickel-containing molten iron by using lower-nickel materials, which belongs to metallurgical industry steel-making raw material. The process comprises the following steps: mixing ferronickel containing raw materials with reducing agent, solvent and catalyst to prepare ultra fine powder, mixing to make pelletizing materials, sending the pelletizing materials into a reducing furnace, obtaining chromium irons pellets after the reduction reaction, and directly adding reduced pellets into an lining electroslag furnace for being smelted into ferronickel alloy or the nickel-containing molten iron.
From RU 2539 884 it is known a method for disposal of metal-containing wastes with iron content 15% and over, such as slags of copper and nickel manufacturing processes, sludge of copper ore floatation and similar materials, and may be used during manufacturing of the construction materials and metal extraction. Ironcontaining wastes are milled to particles size 1-2 mm, mixed with carbonic deoxidant, subjected to reducing roasting at temperature 0.6-0.8 of melting point of most churlish oxide phase of the material. The final stage of the reducing roasting is performed at temperature at least equal to melting point of the less churlish oxide component. The obtained mixture is cooled by thermal shock with rate at least equal to lesser critical cooling rate for the given component, milled to particles size 1 mm and separated by separation method to metal and oxide components.
KR 100 672 089 discloses a method for manufacturing a Fe-Ni alloy mass with excellent strength and high purity more economically by pelletizing FeNi powder in the middle of reduction heat treatment, thereby utilizing FeNi-containing sludge is provided. A method for manufacturing Fe-Ni alloy mass using FeNi-containing sludge comprises the steps of: neutralizing FeNi-containing sludge with a neutralizer to remove chlorine from the FeNi-containing sludge, and drying the chlorine removed FeNi-containing sludge to a moisture content of 5% or less; deagglomerating the dried sludge into powder with an average particle size of 30 to 700 mum; molding the deagglomerated powder into an molded body with a molding density range of 1.7 to 4.7 g/cc; increasing temperature of the molded body at a temperature increasing rate of 100 °C/min or less to sinter the molded body at 500 to 950 °C; performing heat treatment of the sintered material by primarily reducing the sintered material in a temperature range of 500 to 750 °C under a reductive gas atmosphere for 15 to 60 minutes, and secondly reducing the primarily reduced sintered material in a temperature range of 750 to 1000 °C for 15 to 60 minutes such that sintering reaction is occurred during the reduction; and cooling and extracting the reduced and sintered alloy mass.
JPH 11 50162 discloses a recovering method of a valuable metal which can recover it in the form of Fe-Ni alloy or Fe-V alloy and unnecessitate the reseparation at the time of using as alloy additive for iron or steel in a dry type method. Iron component is added to burnt ash obtd. by oxidized-roasting heavy oil ash and removing carbon component, etc., and melted, separated and recovered as a Fe alloy. The melting-separation is executed in two steps of a Fe-Ni alloy recovering step for melting and separating the Fe-Ni alloy and a Fe-V alloy recovering step for melting and separating the Fe-V alloy by adding the iron component and a reducing agent into slag produced in the Fe-Ni alloy recovering step.
WO 2006/089358 discloses a process for producing a ferronickel product from a mixed nickel iron hydroxide product, said process including the steps of : a) providing a mixed nickel iron hydroxide product; b) pelletising the mixed nickel iron hydroxide product to produce nickel iron hydroxide pellets; c) calcining the nickel iron hydroxide pellets to produce mixed nickel iron oxide pellets; and d) reducing the nickel iron oxide pellets with one or more reducing gases at high temperatures to produce ferronickel pellets.
GB 1914/09535 discloses a method for production of nickel-iron alloys from ores containing nickel, iron, and copper sulphides, where the carbonaceous reducingagent is caused to act slowly so as first to reduce iron and subsequently nickel, while copper is left in the slag. For this purpose, the ore is melted down with an excess of lime in an electric furnace lined with carbon; poor ores may first be converted into matte to increase the copper-nickel content.
WO 2016/013356 discloses method for forming pellets from a nickel oxide ore and performing smelting by reducing and heating the pellets in a smelting furnace, wherein it is possible to make the smelting reaction in the reduction step progress effectively while maintaining the strength of the pellets. This method for smelting a nickel oxide ore comprises: a pellet production step S1 for producing pellets from a nickel oxide ore; and a reduction step S2 for reducing and heating the obtained pellets in a smelting furnace at a predetermined reduction temperature. In the pellet production step S1, a mixture is formed by mixing materials including said nickel oxide ore without mixing a carbonaceous reducing agent, and the pellets are formed by agglomerating said mixture. In the reduction step S2, in charging the obtained pellets into the smelting furnace, a carbonaceous reducing agent is spread in advance over the furnace floor of the smelting furnace and the pellets are placed on the carbonaceous reducing agent, and the pellets are reduced and heated in a state where the pellets are covered by the carbonaceous reducing agent.
Objective of the invention
The main objective of the invention is to provide a method for extracting and converting the iron content in the waste material from the iron-precipitation step in nickel sulphide ore based production of nickel to nickel pig iron.
Description of the invention
The invention may be considered as the reduction to practice of the realisation that there is a useful amount of nickel in the solid waste material from the Fe(II)-precipitation step in nickel sulphide ore based production of nickel, such that the iron content may be converted into nickel pig iron.
Thus in a first aspect, the present invention relates to a method for converting waste material from sulphide ore based nickel refining into nickel pig iron, where the waste material comprises NiCl2 and Fe(OH)3 and/or FeOOH,
wherein the method comprises:
- forming a blending mixture comprising the waste material and an amount, adapted to the water content of the waste material, of burnt lime, CaO, which enables converting the blending mixture into solid pellets by mechanically stirring the blending mixture,
- forming a smelting mixture comprising:
i) solid pellets formed by mechanically stirring the blending mixture, ii) elementary carbon in an amount of from 0.07 to 0.21 kg C per kg Fecontent in the solid pellets of the smelting mixture, and
iii) an amount of one or more slag forming compound(s),
- containing the smelting mixture in a melting reactor lined with a carbon free refractory material and heating the smelting mixture under exposure to air and/or other oxygen containing gas from a temperature of around the ambient temperature up to a temperature in the range from about 1400 to about 1600 °C, and
- casting the liquid metal phase formed by the heat treatment of the contained smelting mixture.
The amount of burnt lime to be mixed with the waste material for enabling forming pellets (granules) by mechanically stirring the mixture, depends on the water content of the waste material. Burnt lime reacts strongly exothermically with water in the waste material heating it up and driving off moisture such that too much burnt lime results in a too dry mixture and insufficient formation of pellets, while too less addition of burnt lime makes the mixture into a paste which does not form pellets. Thus, since the water content in the waste material may vary significantly with wherefrom the waste material originates, the required amount of burnt lime to be mixed with the waste material enabling forming the pellets may vary correspondingly wide, making it difficult to define a universally valid upper and lower limit of amount of burnt lime to be added to the waste material in the method of the invention. Thus, the term “an adapted amount of burnt lime, CaO, enabling converting the blending mixture into solid pellets by mechanically stirring the blending mixture” as used herein, means that the present invention encompasses adding any suited amount of burnt lime to the waste material which makes it possible to forming pellets/granules of the mixture by mechanical stirring.
The amount of added burnt lime required to achieve this objective may be determined by a person skilled in the art utilising common general knowledge in straightforward trial and error attempts. Trial and error attempts performed by the inventor indicates that when the waste material has a water content in the range from 35 to 45 weight% water, based on the mass of the waste material, the amount of burnt lime to be mixed with the waste material may advantageously be in the range from 4 to 20 weight%, preferably from 6 to 12 weight%, or most preferably from 7 to 9 weight%, based on the mass of the waste material.
The waste material from the Fe(II)-precipitation step in nickel sulphide ore based production of nickel may contain a substantial amount of water, of 50 weight% or more. One advantage of the present invention is that the pelletizing process, as shown above, requires a substantial amount of water in the pellets-forming mixture to form the pellets such that the need for a dedicated drying process of the waste material may be omitted, or at least made to only removing a relatively small fraction of the water content before processing the waste to nickel pig iron.
In one alternative, the invention according to the invention may further comprise a drying step prior to the pellets formation where the waste material is heated to a temperature of one of the following intervals; from 100 to 300 °C, from 120 to 250 °C, from 120 to 200 °C, or from 120 to 150 °C until the intended water content is obtained, such as e.g. 35 – 45 weight% water, based on the mass of the waste material.
The invention may apply any form of mechanical stirring of the mixture resulting in formation of solid pellets/granules. A suited example embodiment is simply to mechanically stir the mixture comprising the waste material and burnt lime by an impeller in a blender for a period until the dry solid pellets are formed. This may typically be obtained within in a matter of a few minutes with the suited amounts of added burnt lime.
The term “burnt lime” as used herein, means any particulated, preferably fine powdered, calcium oxide of chemical formula CaO. Burnt lime is also known as quicklime in the literature.
In addition to the water, the waste material from the Fe(II)-precipitation step in nickel sulphide ore based production of nickel contains mainly iron present as solid precipitates of ferric hydroxide Fe(OH)3 and/or goethite, FeOOH and about 2 weight% NiCl2. In order to enable reducing the iron and nickel content to elemental iron and nickel, the elements should be transformed to oxides, Fe2O3 and NiO, respectively, which may be reduced to elemental iron and nickel by addition of carbon and heated to a temperature above 1400 °C.
The conversion of the Fe(OH)3 and/or FeOOH and NiCl2 of the waste material to Fe2O3 and NiO, respectively, is according to the invention, obtained by exposing the pellets to air and/or other oxygen containing gas and heating the pellets to a temperature in the range from about 900 °C to about 1400 °C. At this temperature, both FeOOH and NiCl2 present in the pellets will be oxidised to Fe2O3 and NiO, respectively, under exposure to oxygen. This may be achieved by simply heating the pellets under exposure to the ambient atmosphere to these temperatures, or may involve active oxygen supply such as e.g. injection of fresh-air or oxygen gas into the lower part of a bed of the pellets etc.
Another factor which advantageously may be taken into consideration is the content of the impurity compounds in the waste material, such as e.g. As, Cl, and/or S. The chlorine content of the waste material results mainly from the chlorine addition of the Fe(II)-precipitation step in nickel sulphide ore based production of nickel which produces NiCl2 and smaller amounts of other chlorine containing compounds. The NiCl2(s) in the waste material reacts with oxygen during the calcination and forms solid nickel oxide, NiO(s), and the poisonous and chemically aggressive chlorine gas, Cl2(g). Thus, in one alternative embodiment, the invention may further comprise collecting the fumes exiting the smelting mixture during the heating and passing the collected fumes through a chlorine trap or similar measure for removing the chlorine gas in the fumes before venting them into the atmosphere.
Other compounds which may be present in sufficiently high concentrations in the waste material to cause an environmental problem are arsenic and sulphur. Both arsenic (both in elementary form and as oxides) and sulphur have sufficiently high vapour pressures at the temperatures involved in the calcination step to be to more or less driven off with the fumes gassing from the waste material during the calcination, i.e. heating the smelting mixture to a temperature of about 900 °C and up to about 1400 °C. Thus, in one alternative embodiment, the invention may further comprise collecting the fumes exiting the heated smelting mixture and passing the collected fumes through a condenser for condensing the arsenic and/or sulphur content for removing the arsenic and/or sulphur content in the fumes before venting them into the atmosphere.
After the calcining, i.e. the heating to a temperature of from 900 to 1400 °C, the iron and nickel content of the pelletised waste material is mainly present as NiO and Fe2O3, respectively. Both these oxides may be reduced to elementary nickel and iron respectively by heating them with elementary carbon as reducing agent at a temperature in the range of from about 1400 to about 1600 °C. Due to the electronegativity of nickel as compared to iron, the carbon will preferentially reduce the nickel oxide before the ferric iron oxide. This provides an advantage by enabling increasing the nickel concentration in the produced nickel pig iron as compared to the nickel content of the waste material, by simply adding the reduction agent (carbon) in under-stoichiometric amounts (as compared to the total iron content of the calcined waste material) such that not all ferric iron oxide of the waste material becomes reduced to elemental iron. The excess ferric oxide of the calcined waste material will be part of the slag phase above the molten nickel pug iron in the blast furnace.
Experiments made by the inventor indicates that adding carbon to smelting mixture in an amount in the range from 0.07 to 0.21 kg carbon per kg Fe-content in the smelting mixture (i.e. the pellets in the mixture) is a suited under-stoichiometric ratio leading to a nickel content in the iron qualifying to be a commercial grade nickel pig iron. This amount of added carbon to the pellets corresponds to a molar ratio C:Fe in the mixture of approximately 1:3 to 3:3. Thus, the term “carbon in an amount of from 0.07 to 0.21 kg C per kg Fe-content in the solid pellets” as used herein, is to be interpreted in relation to the mass balance of the materials being fed into the smelting reactor such that the reduction process taking place in the smelting reactor is performed with a mass balance between the iron and carbon in the window from 0.07 to 0.21 kg C per kg Fe. For example, if the pelletized waste material inside the smelting reactor contains a total of e.g. 5000 kg ferric oxide, Fe2O3, which corresponds to about 3500 kg Fe, the carbon addition to the smelting mixture is to be in the range from 250 to 750 kg elementary carbon. Alternatively, the method according to the present invention may apply an addition of carbon per kg Fe present in the waste material in one of the following ranges; from 0.09 to 0.19 kg C per kg Fe, preferably from 0.10 to 0.18 kg C per kg Fe, more preferably from 0.11 to 0.17 kg C per kg Fe, more preferably from 0.12 to 0.16 kg C per kg Fe, more preferably from 0.13 to 0.15 kg C per kg Fe, and most preferably from 0.135 to 0.145 kg C per kg Fe present in the waste material.
The molten metal (nickel pig iron) formed at the bottom of the melting reactor may advantageously be protected from oxygen and other reactive constituents of the ambient atmosphere by a protective slag cover. In order to enable forming a protective cover above the molten nickel pig iron, the smelting mixture may advantageously contain at least some amount of at least one slag forming compound which will form a molten slag phase above the molten metal phase. The chemical composition of the melt of molten metal may have an impact on which slag system which should be applied. For instance, if the melt contains acidic minerals it may be advantageous applying an acidic slag composition, and if vice versa, if the melt contains alkaline minerals it may be advantageous applying an alkaline slag composition. The pelletized waste material according to the first aspect of the invention contains mainly iron oxides, i.e. it is very little of other mineral phases in the melt, such that it may optionally be applied either acidic or basic slag compositions. That is, the invention according to the first aspect of the invention may apply any slag forming compound or mixture of compounds in any amount which forms a suited slag cover for liquid iron melts.
Slag protection of liquid iron is well known to the person skilled in the art such that there is no need for a more detailed specification. A person skilled in the art is able from common general knowledge and/or simple trial and error tests to determine the amounts and which slag forming compound(s) to be added into the blast furnace to obtain a satisfactory slag protection and slag refining of the molten nickel pig iron.
However, since the pellets were formed by adding CaO to the waste material, the invention may advantageously apply alkaline slag compositions which are known to be suited for ferronickel melts in combination with a crucible lining of MgO.
Alkaline slag compositions have the advantage of being efficient absorbers of sulphur and chlorine, two contamination elements present in the waste material. Furthermore, alkaline reducing slag systems have the advantage that they typically comprise mainly basic oxides such as CaO, FeO, MgO, MnO, etc. An especially preferred example embodiment of a slag system for use in the present invention is a slag composition comprising 70 – 80 weight% FeO, 10 – 20 weight% CaO and up to 5 weight% SiO2. This example embodiment has the advantage that both CaO and FeO are present in smelting mixture being fed to the melting reactor since the CaO is employed as pelletizing agent in the waste material, and the under-stoichiometric addition of carbon as reducing agent ensures that there is also present an amount of only partly reduced iron, i.e. FeO, in the material in the blast zone. Thus the need for adding slag forming compounds in the smelting mixture becomes substantially reduced, and may even be entirely eliminated if an amount of SiO2 particles are incorporated into the blending mixture (together with the CaO) applied to form the pellets.
This advantage may be further enhanced by also adding the elementary carbon to the blending mixture such that resulting pellets contain the nickel and iron required to form the nickel pig iron, the slag forming compounds required to form the protective slag cover and the elementary carbon required to reduce the intended amount of nickel and iron content of the waste material. In this example embodiment the smelting mixture may simply be only pellets, and the nickel pig iron may be formed by simply placing the pellets in the melting reactor and heating them up to the smelting temperature.
Furthermore, fly ash from municipal waste incineration and other incineration processes have often relatively high contents of both burnt lime, CaO, and silica, SiO2, and may thus advantageously be applied as slag forming addition, either to the blending mixture for being incorporated in the pellets or to the smelting mixture. This example embodiment has the advantage of providing the slag forming compounds at very favourable costs and at the same time solving another problematic waste disposal problem. Fly ash often contains dangerous levels of dioxins and furan, C4H4O, making it necessary to deposit the fly ash in specially secured deposits. However, both dioxin and furan are organic compounds which would be completely destroyed when exposed to molten iron.
The use of carbon as reduction agent has another advantage of being a reducing agent also for eventual remains of arsenic oxides after the calcination step, reducing the arsenic oxides to elementary arsenic which is very volatile at the temperatures of molten nickel pig iron. Thus, as an alternative, it may be added an amount of carbon to the dried waste material to enable removing more arsenic during the calcination by reducing arsenic oxide to elementary arsenic. At the calcining temperatures of the first aspect of the invention, the addition of elementary carbon to the waste material may have the effect of partially reducing the ferric oxide Fe2O3 of the waste material to iron(II, III) oxide, magnetite, Fe3O4. However, both iron oxides, Fe2O3 and Fe3O4, will be reduced to elementary Fe during the subsequent melting step of the method according to the first aspect of the invention. The amount of arsenic in the waste material is usually sufficiently low to ignore the carbon consumption for reducing the arsenic oxide to arsenic, such that the addition of elementary carbon does not need to take the arsenic content into consideration since it is approx. two orders of magnitude lower than the iron content. However, if the arsenic content is significantly higher, the amount of carbon added to the waste material may advantageously take the arsenic content of the waste material into consideration.
One advantage of the present invention is that the heating of the smelting mixture from around the ambient temperature up to the smelting temperature of 1400 to 1600 °C, is that the waste material is successively calcined and then reduced to elementary metal in one process step. There is no need for a dedicated calcining step.
An example embodiment of a suited melting reactor is a blast furnace. A blast furnace enables continuous production of nickel pig iron since feeding the smelting mixture to the upper section of the blast furnace will cause the mixture to gradually sink towards the melting zone and thus be gradually heated from the ambient temperature (typically room temperature) up to the melting temperature of 1400 – 1600 °C as the lower content of smelting mixture is melted, reduced to nickel pig iron and tapped off. The Fe(OH)3 and/or FeOOH and NiCl2 content of the pellets is thus automatically calcined to Fe2O3 and NiO before reaching the temperatures where the oxides are reduced and forms liquid nickel pig iron.
Thus, in an example embodiment, the method of the first aspect of the invention may further comprise:
- applying a blast furnace as the melting reactor, where the blast furnace has:
i) a vertically oriented reactor space being closed in the lower end and open in the upper end and having a carbon free refractory lining,
ii) an inlet for feed material at the upper end of the reactor space,
iii) an outlet for tapping off molten nickel pig iron at the lower section of the reactor space,
iv) heating means adapted to maintaining a temperature of the molten metal at the bottom of the reactor space in the range from 1400 to 1600 °C, v) an outlet for tapping off molten slag formed on top of the molten nickel pig iron, and
vi) an inlet for injecting an oxygen containing blast gas into a blast zone of the reactor space located above the molten slag inside the reactor space, - inserting the smelting mixture through the inlet for feed material,
- optionally, injecting an oxygen containing blast gas into the blast zone through the inlet for injection of blast, and
- tapping off and casting nickel pig iron formed in the blast furnace.
The heating means for maintaining a temperature of 1400 to 1600 °C at the lower section of the reactor space may be any known and conceivable means for obtaining this temperature range in a blast furnace, including but not limited to, induction heating, electric resistance heaters, plasma arc heating etc.
The resulting nickel pig iron from the method according to the invention may have nickel contents up to 5 weight%, and is thus a valuable ferroalloy product for the steel industry. The invention according to the first aspect is thus able to remove the problematic waste disposal from sulphide ore based nickel production, and optionally also the problematic disposal of fly ash from incineration of municipal waste and other solid wastes.
Figures
Figure 1 is an optical photograph of a sample of the waste material from a Fe(II)-precipitation step at a nickel production facility.
Figure 2 is an optical photograph of the waste material after pelletizing the waste material shown in figure 1.
Figure 3 is an optical photograph showing the nickel pig iron formed by reducing the pellets shown in figure 2 according to the invention.
Verification of the invention
The invention will be described in further detail by way of an example embodiment.
In the example embodiment, it is applied waste material from the Fe(II)-precipitation step at Glencore Nikkelverk AS in Kristiansand, Norway. A photograph shown in figure 1 illustrates the consistence of the waste material as a moist slurry. This waste material typically contains about 60 weight% Fe, 1 – 3 weight% Ni, 1 – 3 weight% S, 3 – 5 weight% Cl, and about 1 weight% As. The rest is mainly water and other impurities. The waste material has an orange colour, an indication that the iron of the material is mainly present as goethite, FeOOH.
Two attempts to make pellets were made. In the first attempt, 5 kg waste material (as shown in the photograph of Figure 1) was added 0.5 kg CaO, i.e. a relatively high amount of CaO of 20 weight%. The mixture was stirred for about 3,5 minutes in an Eirich Labormischer R01. The impeller was operated with an impeller speed at 2 m/s the first 30 seconds, then at 15 m/s the next 30 seconds, then at 5 m/s for the 108 seconds and 3 m/s the last 42 seconds. The resulting pellets are shown in the photograph in figure 2.
In the second attempt of making pellets, it was added 300 g CaO to 2.26 kg of the waste material (13.2 weight%), and the mixture was stirred in an Eirich Labormischer R01 operating with an impeller speed of 15 m/s for 30 seconds and then with 3 m/s for 150 seconds. The resulting pellets had a fine integrity and were somewhat larger in particle size as compared to the first example but still relatively small. This indicates that the amount of CaO may be somewhat lowered to obtain larger pellets.
15 kg of pellets (as pictured in the photograph of Figure 2) was made as described above. The amount of dry matter in these pellets was 9 kg, and the dry matter had a composition of 47.3 weight% Fe, 2.4 weight% Ni, and 1 weight% CaO, based on the amount of dry matter. The pellets were mixed with 0.62 kg of activated carbon, 1.86 kg of CaO, and 0.31 kg of particulate SiO2 and divided into two portions. The first portion of the mixture was placed in a graphite crucible. The graphite crucible was then heated in a 75 kW induction furnace from room temperature up to 1500 °C within 45 minutes and maintained at this temperature for a period of 30 minutes. As the mixture melted, the remaining portion of the mixture was added and melted. Then the liquid phase was tapped into a mould and solidified.
The slag was self-disintegrating into a powder having a mass of 2.45 kg and the solidified metal after casting, see photograph in Figure 3, had a mass of 3.37 kg. The chemical composition of the casted metal (nickel pig iron) was: 95 weight% Fe and 3.2 weight% Ni, and further 0.006 weight% Al, 0.25 weight% As, 0.29 weight% Co, 0.01 weight% Cr, 0.022 weight% Cu, 0.34 weight% Mn, 0.76 weight% O, 0.13 weight% S, 0.018 weight% Si, and 0.006 weight% Zn.
The above experiment is proof of concept that the invention enables producing nickel pig iron from waste material from the Fe(II)-precipitation step at Glencore Nikkelverk AS in Kristiansand, Norway. The resulting nickel pig iron has somewhat small amount of Ni. This is due to the use of a graphite crucible which was attacked by the melt (it was partly dissolved) and thus supplied more carbon as reduction agent to the process than the required 0.07 to 0.21 kg C per kg Fe-content in the solid pellets. As a result, a higher portion of the goethite content of the waste was converted to elementary iron than would have been the case with using a carbon free crucible.
Claims (13)
1. A method for converting a waste material from sulphide ore based nickel refining into nickel pig iron, where the waste material comprises NiCl2 and Fe(OH)3 and/or FeOOH,
wherein the method comprises:
- forming a blending mixture comprising the waste material and an amount, adapted to the water content of the waste material, of burnt lime, CaO, which enables converting the blending mixture into solid pellets by mechanically stirring the blending mixture,
- forming a smelting mixture comprising:
i) solid pellets formed by mechanically stirring the blending mixture, ii) elementary carbon in an amount of from 0.07 to 0.21 kg C per kg Fecontent in the solid pellets of the smelting mixture, and
iii) an amount of one or more slag forming compound(s),
- containing the smelting mixture in a melting reactor lined with a carbon free refractory material and heating the smelting mixture under exposure to air and/or other oxygen containing gas from a temperature of around the ambient temperature up to a temperature in the range from about 1400 to about 1600 °C, and
- casting the liquid metal phase formed by the heat treatment of the contained smelting mixture.
2. A method according to claim 1, wherein the solid pellets are formed by mechanically stirring the blending mixture by an impeller in a blender.
3. A method according to claim 1 or 2, wherein, prior to the pelletizing step, the method further comprises a drying step of the waste material by heating the waste material to a temperature of from 100 to 300 °C, preferably from 120 to 250 °C, more preferably from 120 to 200 °C, or most preferably from 120 to 150 °C, and maintaining this temperature until a water content of from 35 to 45 weight%, based on the mass of the waste material, is obtained.
4. A method according to any preceding claim, wherein the amount of burnt lime, CaO, being added to form the blending mixture is in the range from 4 to 20 weight% CaO, preferably from 6 to 12 weight% CaO, or most preferably from 7 to 9 weight% CaO, based on the mass of the waste material.
5. A method according to any preceding claim, wherein the carbon free refractory lining of the melting reactor is MgO.
6. A method according to any preceding claim, wherein the slag forming compounds comprises one or more of: CaO, FeO, MgO, and MnO.
7. A method according to claim 5, wherein the slag forming compounds comprises 70 – 80 weight% FeO, 10 – 20 weight% CaO and up to 5 weight% SiO2, based on the total mass of the slag forming compounds.
8. A method according to claims 6 or 7, wherein the slag forming compounds further comprises fly ash from municipal waste incineration.
9. A method according to claim 7, wherein the slag forming compounds are incorporated into the pellets by adding the slag forming compounds to the blending mixture before forming the pellets.
10. A method according to any preceding claim, wherein the amount of carbon in the smelting mixture is one of the following ranges; from 0.09 to 0.19 kg C per kg Fe, preferably from 0.11 to 0.17 kg C per kg Fe, more preferably 0.11 to 0.17 kg C per kg Fe, more preferably from 0.12 to 0.16 kg C per kg Fe, more preferably from 0.13 to 0.15 kg C per kg Fe, and most preferably from 0.135 to 0.145 kg C per kg Fe present in the smelting mixture.
11. A method according to any preceding claim, wherein the method further comprises:
- applying a blast furnace as the melting reactor, where the blast furnace has:
i) a vertically oriented reactor space being closed in the lower end and open in the upper end and having a carbon free refractory lining,
ii) an inlet for feed material at the upper end of the reactor space,
iii) an outlet for tapping off molten nickel pig iron at the lower section of the reactor space,
iv) heating means adapted to maintaining a temperature of the molten metal at the bottom of the reactor space in the range from 1400 to 1600 °C, v) an outlet for tapping off molten slag formed on top of the molten nickel pig iron, and
vi) an inlet for injecting an oxygen containing blast gas into a blast zone of the reactor space located above the molten slag inside the reactor space, - inserting the smelting mixture through the inlet for feed material,
- optionally, injecting an oxygen containing blast gas into the blast zone through the inlet for injection of blast, and
- tapping off and casting nickel pig iron formed in the blast furnace.
12. A method according to claim 11, wherein the fumes exiting the blast furnace is collected and passed through a chlorine trap or similar measure for removing the chlorine gas in the fumes before venting them into the atmosphere.
13. A method according to claim 11 or 12, wherein the fumes exiting the blast furnace is collected and passed through a condenser for condensing the arsenic and/or sulphur content for removing the arsenic and/or sulphur content in the fumes before venting them into the atmosphere.
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| EP1927667A1 (en) * | 2005-09-16 | 2008-06-04 | Shenjie Liu | A smelting process of ferronickel with nickel oxide ore free of crystal water in a blast furnace |
| WO2016013356A1 (en) * | 2014-07-25 | 2016-01-28 | 住友金属鉱山株式会社 | Method for smelting nickel oxide ore and method for charging pellets |
| WO2016103812A1 (en) * | 2014-12-24 | 2016-06-30 | 住友金属鉱山株式会社 | Method for smelting nickel oxide ore |
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| GB191409535A (en) * | 1913-07-31 | 1915-07-15 | Wilhelm Borchers | Improvements in and relating to the Production of Nickel Iron Alloys. |
| EP1927667A1 (en) * | 2005-09-16 | 2008-06-04 | Shenjie Liu | A smelting process of ferronickel with nickel oxide ore free of crystal water in a blast furnace |
| WO2016013356A1 (en) * | 2014-07-25 | 2016-01-28 | 住友金属鉱山株式会社 | Method for smelting nickel oxide ore and method for charging pellets |
| WO2016103812A1 (en) * | 2014-12-24 | 2016-06-30 | 住友金属鉱山株式会社 | Method for smelting nickel oxide ore |
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| Publication number | Publication date |
|---|---|
| NO20170743A1 (en) | 2018-11-06 |
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