CA3211609C - Method for producing aqueous solution containing nickel or cobalt - Google Patents
Method for producing aqueous solution containing nickel or cobalt Download PDFInfo
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- CA3211609C CA3211609C CA3211609 CA3211609C CA 3211609 C CA3211609 C CA 3211609C CA 3211609 CA3211609 CA 3211609 CA 3211609 C CA3211609 C CA 3211609C
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- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 title claims abstract description 152
- 229910017052 cobalt Inorganic materials 0.000 title claims abstract description 108
- 239000010941 cobalt Substances 0.000 title claims abstract description 108
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 title claims abstract description 108
- 229910052759 nickel Inorganic materials 0.000 title claims abstract description 76
- 239000007864 aqueous solution Substances 0.000 title claims abstract description 47
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 30
- 238000002386 leaching Methods 0.000 claims abstract description 78
- 239000000706 filtrate Substances 0.000 claims abstract description 67
- 239000012535 impurity Substances 0.000 claims abstract description 62
- 239000000243 solution Substances 0.000 claims abstract description 58
- 238000001556 precipitation Methods 0.000 claims abstract description 53
- 238000010438 heat treatment Methods 0.000 claims abstract description 51
- 239000011777 magnesium Substances 0.000 claims abstract description 36
- 229910052749 magnesium Inorganic materials 0.000 claims abstract description 35
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 31
- 239000002904 solvent Substances 0.000 claims abstract description 31
- 238000000605 extraction Methods 0.000 claims abstract description 30
- 239000012044 organic layer Substances 0.000 claims abstract description 29
- 230000001376 precipitating effect Effects 0.000 claims abstract description 27
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 claims abstract description 25
- 239000013077 target material Substances 0.000 claims abstract description 23
- 239000002994 raw material Substances 0.000 claims abstract description 22
- 230000003472 neutralizing effect Effects 0.000 claims abstract description 20
- 229910052791 calcium Inorganic materials 0.000 claims abstract description 19
- 239000011575 calcium Substances 0.000 claims abstract description 19
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 claims abstract description 13
- 239000000203 mixture Substances 0.000 claims abstract description 10
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims description 59
- 239000010949 copper Substances 0.000 claims description 38
- 229910052802 copper Inorganic materials 0.000 claims description 36
- 238000000034 method Methods 0.000 claims description 36
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 35
- 239000011701 zinc Substances 0.000 claims description 32
- 229910052725 zinc Inorganic materials 0.000 claims description 22
- HYHCSLBZRBJJCH-UHFFFAOYSA-M sodium hydrosulfide Chemical group [Na+].[SH-] HYHCSLBZRBJJCH-UHFFFAOYSA-M 0.000 claims description 19
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 claims description 17
- PUZPDOWCWNUUKD-UHFFFAOYSA-M sodium fluoride Chemical group [F-].[Na+] PUZPDOWCWNUUKD-UHFFFAOYSA-M 0.000 claims description 16
- 239000002244 precipitate Substances 0.000 claims description 14
- 238000005406 washing Methods 0.000 claims description 13
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 claims description 12
- 229910052708 sodium Inorganic materials 0.000 claims description 12
- 239000011734 sodium Substances 0.000 claims description 12
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 claims description 11
- 238000000746 purification Methods 0.000 claims description 8
- QUXFOKCUIZCKGS-UHFFFAOYSA-N bis(2,4,4-trimethylpentyl)phosphinic acid Chemical group CC(C)(C)CC(C)CP(O)(=O)CC(C)CC(C)(C)C QUXFOKCUIZCKGS-UHFFFAOYSA-N 0.000 claims description 7
- 239000000463 material Substances 0.000 claims description 7
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 7
- 239000011775 sodium fluoride Substances 0.000 claims description 5
- 235000013024 sodium fluoride Nutrition 0.000 claims description 5
- 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 claims description 4
- SEGLCEQVOFDUPX-UHFFFAOYSA-N di-(2-ethylhexyl)phosphoric acid Chemical compound CCCCC(CC)COP(O)(=O)OCC(CC)CCCC SEGLCEQVOFDUPX-UHFFFAOYSA-N 0.000 claims description 3
- 244000126002 Ziziphus vulgaris Species 0.000 claims 2
- 238000006243 chemical reaction Methods 0.000 description 50
- 238000011068 loading method Methods 0.000 description 20
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 18
- 229910052751 metal Inorganic materials 0.000 description 11
- 239000002184 metal Substances 0.000 description 11
- 229910000029 sodium carbonate Inorganic materials 0.000 description 9
- 235000011149 sulphuric acid Nutrition 0.000 description 9
- 229910052748 manganese Inorganic materials 0.000 description 8
- 239000011572 manganese Substances 0.000 description 8
- 229910017518 Cu Zn Inorganic materials 0.000 description 7
- 238000010586 diagram Methods 0.000 description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 6
- 238000000926 separation method Methods 0.000 description 6
- 229910017709 Ni Co Inorganic materials 0.000 description 5
- OMZSGWSJDCOLKM-UHFFFAOYSA-N copper(II) sulfide Chemical compound [S-2].[Cu+2] OMZSGWSJDCOLKM-UHFFFAOYSA-N 0.000 description 5
- 238000004880 explosion Methods 0.000 description 5
- 150000002739 metals Chemical class 0.000 description 5
- 239000003960 organic solvent Substances 0.000 description 5
- 238000011084 recovery Methods 0.000 description 5
- 239000007787 solid Substances 0.000 description 5
- 238000000638 solvent extraction Methods 0.000 description 5
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 4
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 4
- 239000007832 Na2SO4 Substances 0.000 description 4
- PMZURENOXWZQFD-UHFFFAOYSA-L Sodium Sulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=O PMZURENOXWZQFD-UHFFFAOYSA-L 0.000 description 4
- 229910052938 sodium sulfate Inorganic materials 0.000 description 4
- 235000011152 sodium sulphate Nutrition 0.000 description 4
- 239000002253 acid Substances 0.000 description 3
- 238000005265 energy consumption Methods 0.000 description 3
- -1 (A) a leaching step Chemical compound 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- 239000006182 cathode active material Substances 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 239000012467 final product Substances 0.000 description 2
- 229910052742 iron Inorganic materials 0.000 description 2
- OAOABCKPVCUNKO-UHFFFAOYSA-N 8-methyl Nonanoic acid Chemical compound CC(C)CCCCCCC(O)=O OAOABCKPVCUNKO-UHFFFAOYSA-N 0.000 description 1
- 229910020634 Co Mg Inorganic materials 0.000 description 1
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 1
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 1
- 229910013724 M(OH)2 Inorganic materials 0.000 description 1
- 229910004840 Na2CO3—Na2SO4 Inorganic materials 0.000 description 1
- WUKWITHWXAAZEY-UHFFFAOYSA-L calcium difluoride Chemical compound [F-].[F-].[Ca+2] WUKWITHWXAAZEY-UHFFFAOYSA-L 0.000 description 1
- 229910001634 calcium fluoride Inorganic materials 0.000 description 1
- KTVIXTQDYHMGHF-UHFFFAOYSA-L cobalt(2+) sulfate Chemical compound [Co+2].[O-]S([O-])(=O)=O KTVIXTQDYHMGHF-UHFFFAOYSA-L 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000006378 damage Effects 0.000 description 1
- 230000003628 erosive effect Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 229910052744 lithium Inorganic materials 0.000 description 1
- 229910001416 lithium ion Inorganic materials 0.000 description 1
- ORUIBWPALBXDOA-UHFFFAOYSA-L magnesium fluoride Chemical compound [F-].[F-].[Mg+2] ORUIBWPALBXDOA-UHFFFAOYSA-L 0.000 description 1
- 229910001635 magnesium fluoride Inorganic materials 0.000 description 1
- 238000002156 mixing Methods 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
- 229910000008 nickel(II) carbonate Inorganic materials 0.000 description 1
- 229910000363 nickel(II) sulfate Inorganic materials 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 230000035484 reaction time Effects 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- NWONKYPBYAMBJT-UHFFFAOYSA-L zinc sulfate Chemical compound [Zn+2].[O-]S([O-])(=O)=O NWONKYPBYAMBJT-UHFFFAOYSA-L 0.000 description 1
- 229910000368 zinc sulfate Inorganic materials 0.000 description 1
- 239000011686 zinc sulphate Substances 0.000 description 1
- 235000009529 zinc sulphate Nutrition 0.000 description 1
Abstract
A method for producing an aqueous solution containing nickel or cobalt includes: (A) a leaching step, which includes a first atmospheric pressure heating leaching step and a second atmospheric pressure heating leaching step, in which a raw material is heated and leached under an atmospheric pressure to form a leachate solution containing nickel, cobalt, and impurities; (B) a first extraction step of separating the leachate solution into a first filtrate containing nickel and impurities and a first organic layer containing cobalt and impurities by adding a first solvent extractant to the leachate solution; (C-i) a precipitation removal step of precipitating and removing impurities including magnesium, calcium, or a mixture thereof by adding a precipitating agent to the first filtrate; and (D-i) a target material precipitation step of selectively precipitating a nickel cake containing nickel by adding a neutralizing agent to the first filtrate.
Description
METHOD FOR PRODUCING AQUEOUS SOLUTION CONTAINING NICKEL OR
COBALT
TECHNICAL FIELD
[0001] The present invention relates to a method for producing an aqueous solution containing nickel or cobalt. More specifically, the present invention relates to a method for producing an aqueous solution containing nickel or cobalt for recovering nickel and cobalt from a raw material and then producing an aqueous solution containing nickel or cobalt that can be used for producing a cathode active material of a lithium ion secondary battery.
BACKGROUND
COBALT
TECHNICAL FIELD
[0001] The present invention relates to a method for producing an aqueous solution containing nickel or cobalt. More specifically, the present invention relates to a method for producing an aqueous solution containing nickel or cobalt for recovering nickel and cobalt from a raw material and then producing an aqueous solution containing nickel or cobalt that can be used for producing a cathode active material of a lithium ion secondary battery.
BACKGROUND
[0002] A one-stage atmospheric pressure heating reaction leaching process, or a two-stage leaching process consisting of an atmospheric pressure heating reaction and a pressurizing heating reaction has been mainly used to ionize nickel and cobalt from a mixed hydroxide precipitate (MHP) cake raw material containing nickel/cobalt mixed hydroxide.
[0003] However, in the case of the one-stage atmospheric pressure heating reaction leaching process, a problem occurs in that the recovery rate of Ni and Co decreases. In the case of the two-stage leaching process consisting of an atmospheric pressure heating reaction and a pressurizing heating reaction, a problem is posed in that the range of material selection is reduced due to erosion, corrosion, damage, etc. of pipe and reactor materials, and the competitiveness is lowered due to energy costs.
[0004] In addition, nickel and cobalt were selectively recovered from the ionized aqueous of nickel/cobalt solution using a solvent extractant such as Ion quest 801, Cyanex 272, Versatic Acid 10, or LIX 841. However, there is a risk of fire and explosion due to the use of an organic solvent in a solvent extraction process. The high unit price of the solvent extractant increases the cost of producing high-purity nickel sulfate and cobalt, thereby reducing competitiveness in terms of price.
Date Regue/Date Received 2024-03-06 SUMMARY
Date Regue/Date Received 2024-03-06 SUMMARY
[0005] An object of the present invention is to produce a high-purity aqueous solution by recovering nickel and cobalt from an MHP cake raw material containing nickel/cobalt mixed hydroxide.
[0006] In addition, it is an object of the present invention to improve a nickel/cobalt recovery rate and reduce energy consumption by ionizing nickel and cobalt using a two-stage atmospheric pressure heating leaching step.
[0007] In addition, it is an object of the present invention to separate magnesium and calcium using sodium fluoride (NaF) as a precipitant in an aqueous solution containing high-purity nickel production step, separate magnesium and manganese through a solubility difference using sodium hydrogen sulfide (NaSH) in an aqueous solution containing high-purity cobalt production step, and additionally separate impurities such as copper, magnesium, and manganese through the use of sodium hydrogen sulfide (NaSH) and sodium fluoride (NaF), thereby reducing the solvent extraction step.
[0008] Since the solvent extraction step has a risk of fire and explosion due to the use of an organic solvent, it is an object of the present invention to minimize the solvent extraction step, thereby improving the operating environment and reducing the production cost of a final product.
[0009] According to one aspect of the present invention, there is provided a method for producing an aqueous solution containing nickel or cobalt, including: (A) a leaching step, which includes a first atmospheric pressure heating leaching step and a second atmospheric pressure heating leaching step, in which a raw material is heated and leached under an atmospheric pressure to form a leachate solution containing nickel, cobalt, and impurities; (B) a first extraction step of separating the leachate solution into a first filtrate containing nickel and impurities and a first organic layer containing cobalt and impurities by adding a first solvent extractant to the leachate solution; (C-i) a precipitation removal step of precipitating and removing impurities including magnesium, calcium, or a mixture thereof by adding a precipitating agent to the first filtrate; and (D-i) a target material precipitation step of selectively Date Regue/Date Received 2024-03-06 precipitating a nickel cake containing nickel by adding a neutralizing agent to the first filtrate from which the impurities are precipitated and removed.
[0010] According to another aspect of the present invention, there is provided a method for producing an aqueous solution containing nickel or cobalt, including: (A) a leaching step, which includes a first atmospheric pressure heating leaching step and a second atmospheric pressure heating leaching step, in which a raw material is heated and leached under an atmospheric pressure to fonii a leachate solution containing nickel, cobalt, and impurities; (B) a first extraction step of separating the leachate solution into a first filtrate containing nickel and impurities and a first organic layer containing cobalt and impurities by adding a first solvent extractant to the leachate solution; and (C-ii) a purification step of removing impurities including magnesium, manganese, zinc, copper, or mixtures thereof by adding a sulfuric acid solution to the first organic layer to produce a second filtrate, and adding sulfide to the second filtrate to precipitate and recover a cobalt precipitate.
100111 In an embodiment of the present invention, a pH of the filtrate obtained in the second atmospheric pressure heating leaching step may be lower than a pH of the filtrate obtained in the first atmospheric pressure heating leaching step.
[0012] In an embodiment of the present invention, the filtrate obtained in the second atmospheric pressure heating leaching step may be fed to the first atmospheric pressure heating leaching step.
[0013] In an embodiment of the present invention, the first solvent extractant may be bis (2,4,4-trimethylpentyl) phosphinic acid.
[0014] In an embodiment of the present invention, the first extraction step may be carried out at a temperature of 40 degrees C and a pH of greater than 5.0 and less than 5.4.
[0015] In an embodiment of the present invention, the precipitating agent may be sodium fluoride.
[0016] In an embodiment of the present invention, the precipitating agent may be added in an amount of more than 2.0 equivalents and less than 2.4 equivalents of an amount of the magnesium, calcium, or a mixture thereof.
Date Regue/Date Received 2024-03-06 [0017] In an embodiment of the present invention, the neutralizing agent may be a basic material containing sodium.
[0018] In an embodiment of the present invention, after the neutralizing agent is added, the pH
of the first filtrate may be 8 or more at a temperature of 85 degrees C.
[0019] In an embodiment of the present invention, the method may further include: (E-i) a washing step of washing the nickel cake with pure water.
[0020] In an embodiment of the present invention, the sulfide may be sodium hydrogen sulfide (NaSH).
[0021] In an embodiment of the present invention, the sulfide may be added in an amount of more than 1.0 equivalents and less than 1.6 equivalents of an amount of the cobalt and zinc.
[0022] In an embodiment of the present invention, the method may further include: (D-ii) a copper removal step of dissolving the cobalt precipitate in a sulfuric acid solution and then removing copper.
[0023] In an embodiment of the present invention, the copper removal step may be perfoimed by adding sodium hydrogen sulfide (NaSH) in an amount greater than 4.5 equivalents and less than 5.5 equivalents of copper content.
[0024] In an embodiment of the present invention, the method may further include: (E-ii) a second extraction step of separating the copper-removed aqueous solution into a third filtrate containing cobalt and impurities and a second organic layer containing zinc and impurities by adding a second solvent extractant to the copper-removed aqueous solution.
[0025] In an embodiment of the present invention, the second solvent extractant may be D2EHPA (di-(2-ethylhexyl) phosphoric acid).
[0026] In an embodiment of the present invention, the second extraction step may be carried out at a pH of greater than 2.4 and less than 3.2 at a temperature of 40 degrees C.
[0027] In an embodiment of the present invention, the method may further include: (F) a precipitation removal step of precipitating and removing impurities including magnesium by adding a precipitating agent to the third filtrate.
[0028] In an embodiment of the present invention, the method may further include: (G) a target Date Regue/Date Received 2024-03-06 material precipitation step of selectively precipitating a cobalt cake containing cobalt by adding a neutralizing agent to the third filtrate from which the impurities are precipitated and removed.
[0029] In an embodiment of the present invention, after the neutralizing agent is added, the pH
of the third filtrate may be 8 or more at a temperature of 85 degrees C.
[0030] In an embodiment of the present invention, the method may further include: (H) a washing step of washing the cobalt cake with pure water.
[0031] According to the present invention, it is possible to improve the nickel/cobalt recovery rate and reduce the energy consumption by using a two-stage atmospheric pressure heating step.
[0032] In addition, by minimizing the solvent extraction step having a risk of fire and explosion due to the use of an organic solvent in the impurity removal step, it is possible to improve the operating environment and reduce the production cost of a final product.
BRIEF DESCRIPTION OF THE DRAWINGS
[0033] FIG. 1 is a diagram showing a two-stage leaching step and a first extraction step for producing an aqueous solution containing nickel or cobalt according to one embodiment of the present invention.
[0034] FIG. 2 is a diagram showing a precipitation removal step and a target material precipitation step for producing an aqueous solution containing nickel according to one embodiment of the present invention.
[0035] FIG. 3 is a diagram showing an impurity removal step, a copper removal step, a second extraction step, a precipitation removal step, and a target material precipitation step for producing an aqueous solution containing cobalt according to one embodiment of the present invention.
DETAILED DESCRIPTION
[0036] Embodiments of the present disclosure are illustrated for describing the technical spirit of the present disclosure. The scope of the claims according to the present disclosure is not limited to the embodiments described below or to the detailed descriptions of these Date Regue/Date Received 2024-03-06 embodiments.
[0037] The present invention will now be described with reference to the drawings.
[0038] FIG. 1 is a diagram showing a two-stage leaching step S10 and a first extraction step S20 for producing an aqueous solution containing nickel or cobalt according to one embodiment of the present invention. FIG. 2 is a diagram showing a precipitation removal step S31 and a target material precipitation step S32 for producing an aqueous solution containing nickel according to one embodiment of the present invention. FIG. 3 is a diagram showing an impurity removal step S32 and S42, a copper removal step S62, a second extraction step S72, a precipitation removal step S82, and a target material precipitation step S92 for producing an aqueous solution containing cobalt according to one embodiment of the present invention.
[0039] Referring to FIGS. 1 to 3, there may be provided a method for producing an aqueous solution containing nickel or cobalt that can be used for manufacturing a cathode active material of a lithium secondary battery from a mixed hydroxide precipitate (MHP cake) through a series of steps. According to this method, it is possible to improve the operation stability and the purity, and reduce the production cost. Hereinafter, the respective steps will be described in detail with reference to the drawings.
[0040] Firstly, referring to FIG. 1, a leaching step S10 of forming a leachate by performing two-stage atmospheric pressure heating leaching steps on an MHP cake, and a first extraction step S20 of separating the leachate into a first filtrate containing nickel and impurities and a first organic layer containing cobalt and impurities may be performed.
100411 Leaching Step S10 100421 The leaching step S10 is a step of forming a leachate by dissolving an MHP cake in the Rain of hydroxide in an acid solution such as sulfuric acid to ionize the MHP
cake. The leaching step S10 includes a first atmospheric pressure heating leaching step Si! and a second atmospheric pressure heating leaching step S12. The atmospheric pressure heating leaching step is a step of producing an acid solution in an open reactor at a temperature of 100 degrees C
or less, introducing a raw material into the reactor, and leaching valuable metals by a reaction represented by the following Reaction Formula 1. The raw material introduced here may be an Date Regue/Date Received 2024-03-06 MHP cake in the form of hydroxide containing nickel in an amount of 40% by weight.
[0043] Reaction Foimula 1]
[0044] M(OH)2 + H2SO4 MS04 + 2H20 (M is metal such as Ni, Co, or Mg) [0045] The first atmospheric pressure heating leaching step Sll and the second atmospheric pressure heating leaching step S12 may be separately perfoinied in two-stage apparatuses, or may be performed in one pressurization apparatus by changing only the process conditions (e.g., temperature, pressure, or acidity).
[0046] Valuable metals may be leached from the raw material through the first atmospheric pressure heating leaching step S11. For example, valuable metals such as nickel, cobalt, and manganese in the raw material may be leached. In addition, elements such as iron, copper, aluminum, zinc, magnesium, and the like in the raw material may also be leached. The first atmospheric pressure heating leaching step Sll may be performed for about 2 hours at a temperature in the range of 50 degrees C to 70 degrees C and a pH in the range of 2.7 to 3.3.
By satisfying the temperature and the pH, high leaching efficiency can be obtained under optimal conditions.
[0047] In the first atmospheric pressure heating leaching step S11, the solid density of the raw material introduced into the reactor may be 100 g/L or more. For example, the solid density of the raw material may be in the range of 100 g/L to 200 g/L. As used herein, the term "solid density" is defined as the ratio of the mass of the raw material introduced into the pressurization apparatus to the volume of the acid solution previously introduced into the reactor. In other words, the solid density may be the ratio of the mass of the raw material introduced per unit solvent, and may be the mass of the raw material per 1 L of a solvent.
[0048] The filtrate obtained in the first atmospheric pressure heating leaching step S1 1 may be introduced into the first extraction step S20, and the residue may be subsequently treated in the second atmospheric pressure heating leaching step S12.
[0049] In the second atmospheric pressure heating leaching step S12, the leaching residue obtained in the first atmospheric pressure heating leaching step Sll may be leached at a temperature in the range of 80 degrees C to 100 degrees C for about 3 hours.
Other conditions Date Regue/Date Received 2024-03-06 of the second atmospheric pressure heating leaching step S12 may be the same as those of the first atmospheric pressure heating leaching step S11.
[0050] The pH of the filtrate obtained in the second atmospheric pressure heating leaching step S12 may be lower than the pH of the filtrate obtained in the first atmospheric pressure heating leaching step S11. By controlling the pH, the leaching rate in each atmospheric pressure heating leaching step can be increased. Accordingly, the entire amount of the valuable metals contained in the raw material can be leached out. For example, the entire amounts of nickel, cobalt, manganese, iron, copper, aluminum, zinc, and magnesium contained in the raw material can be leached out.
[0051] In one embodiment, the filtrate formed in the second atmospheric pressure heating leaching step S12 may be fed to the first atmospheric pressure heating leaching step S11 as shown in FIG. 1.
[0052] In the case of a commonly used atmospheric pressure leaching method, the reaction time has to be continued for 18 hours or longer to increase the leaching rate of valuable metals. In this case, additional costs are incurred due to the increased use of fuel and steam. The productivity is low because the amount of raw material processed per day is small. However, according to one embodiment of the present invention, by using the two-stage atmospheric pressure heating leaching method, it is possible to improve the recovery rate of nickel and cobalt and reduce the energy consumption. Thus, it is possible to reduce the production cost and improve the productivity.
[0053] The residue generated in the second atmospheric pressure heating leaching step S12 may be discarded as shown in FIG. 1.
[0054] First Extraction step S20 [0055] The first extraction step S20 is a step of selectively separating or extracting nickel from the aqueous solution containing nickel/cobalt (leachate solution) ionized through the two-stage atmospheric pressure heating leaching step by using a first solvent extractant.
[0056] In this regard, the first solvent extractant is not particularly limited as long as the loading rate of nickel is low, and may be, for example, bis(2,4,4-trimethylpentyl) phosphinic acid Date Regue/Date Received 2024-03-06 (Cyanex272).
[0057] When the first solvent extractant is added to the leachate, nickel may be not loaded into the first solvent extractant and may be distributed to the first filtrate (Raffinate). Cobalt and other impurities (Mg, Mn, Zn, etc.) may be separated or extracted by being distributed to an organic layer together with the first solvent extractant. This separation or extraction can occur according to the reactions represented by Reaction Formulae 2 and 3 below. In this regard, the reaction of Reaction Formula 3 is a reaction for maintaining the pH by neutralizing H2SO4 formed by the reaction of Reaction Formula 2.
[0058] [Reaction Founula 2]
[0059] 2HR(org.) + MS04(aq.) MR2(org.) + H2SO4(aq.) (R is Ni etc., and M is Co, Mg, Mn etc.) [0060] [Reaction Foimula 3]
[0061] H2SO4 + Na2CO3 Na2SO4+ H20 + CO2 [0062] The first extraction step may be perfonned at a temperature of 40 degrees C and a pH of greater than 5.0 and less than 5.4. By satisfying the temperature and the pH, it is possible to increase the loading rate of cobalt and impurities, and efficiently separate nickel into the filtrate.
[0063] In one embodiment, the ratio of the first solvent extractant (0) to the aqueous solution (A) can be controlled according to the concentration of the component to be extracted from the solution. For example, the ratio (0:A) of the first solvent extractant (0) to the aqueous solution (A) may range from 0.5:1 to 2:1. For example, the 0:A may be 1.5:1.
[0064] Referring next to FIG. 2, a precipitation removal step S31 of precipitating and removing impurities from the first filtrate that has passed through the first extraction step S20, a target material precipitation step S41 of selectively precipitating a nickel cake containing high-purity nickel, and a final leaching step of producing an aqueous solution containing high-purity nickel may be performed.
[0065] Precipitation Removal Step S31 [0066] The precipitation removal step S31 may be performed to remove impurities such as magnesium, calcium, or a mixture thereof remaining in the first filtrate.
After the precipitation Date Regue/Date Received 2024-03-06 removal step S31, the first filtrate may be fed to the target material precipitation step S41.
[0067] For example, in the precipitation removal step S31, a removing agent may be introduced into the solution. The removing agent is not particularly limited as long as it can react with magnesium or calcium to form a precipitate. The removing agent may be, for example, sodium fluoride (NaF).
[0068] For example, magnesium and calcium may be precipitated as magnesium fluoride or calcium fluoride through a reaction represented by Reaction Foimula 4 below.
[0069] For example, by performing the precipitation removal step S31 for about 2 hours or more at a reaction temperature in the range of 50 degrees C to 70 degrees C, only magnesium and calcium can be separated through selective precipitation while reducing nickel precipitation in the filtrate.
[0070] [Reaction Foimula 4]
[0071] MS04 + 2NaF = MF2 + Na2SO4 (M is Mg or Ca) [0072] In one embodiment, sodium fluoride may be added in an amount greater than 2.0 equivalents (eq) of magnesium, calcium or a mixture thereof. In another embodiment, sodium fluoride may be added in an amount less than 2.4 equivalents (eq) of magnesium, calcium or a mixture thereof.
[0073] Target Material Precipitation Step S41 [0074] In the target material precipitation step S41, a neutralizing agent may be added to the first filtrate after the precipitation removal step S31.
[0075] For example, the neutralizing agent may be a basic material containing sodium. For example, the neutralizing agent may be sodium carbonate (Na2CO3).
[0076] After removing impurities such as magnesium and calcium, in the target material precipitation step S41, nickel may be precipitated in the form of a cake through a reaction indicated by Reaction Formula 5 below.
[0077] [Reaction Foimula 5]
[0078] 3NiSO4 + 3Na2CO3 +2H20 = NiCO3=2Ni(OH)2 + 3Na2SO4 +3CO2 [0079] The target material precipitation step S41 may be performed for 4 hours or more at a pH
Date Regue/Date Received 2024-03-06 of 8 or higher and a temperature in the range of 80 degrees C to 90 degrees C.
[0080] Since nickel can be recovered through the target material precipitation step S41, it is possible to reduce the use of expensive organic solvents that have a risk of explosion and fire.
Thus, it is possible to improve the operational stability and the productivity, and reduce the production costs.
[0081] Although not specifically shown in the drawings, some sodium components may be present in the precipitated nickel cake. Therefore, the water-soluble sodium components can be removed by a washing step using pure water at the rear stage. In this case, the production cost can be reduced by reusing the removed sodium components in producing sodium carbonate (Na2CO3), which is a neutralizing agent.
[0082] Final Leaching Step S51 [0083] The final leaching step S51 is a step of producing an aqueous solution containing high-purity nickel by removing components such as sodium and the like through washing and dissolving the nickel cake in a sulfuric acid solution.
[0084] In the final leaching step S51, the nickel cake may be added to a solution obtained by mixing pure water with sulfuric acid at an acidity of 150 g/L to 200 g/L.
Nickel, cobalt, and trace impurities contained in the nickel cake can be dissolved in the sulfuric acid solution. The sulfuric acid solution and the nickel cake are reacted until the pH becomes 2Ø According to one embodiment, in the final leaching step S51, the reaction may be performed for 4 hours or more at a pH in the range of 1.0 to 3.0 and a temperature in the range of 50 degrees C to 70 degrees C.
[0085] Referring next to FIG. 3, a second filtrate production step S32 of adding a sulfuric acid solution to the first organic layer that has passed through the first extraction step S20, a purification step S42 of precipitating and recovering a cobalt precipitate from the second filtrate and purifying impurities, a step S52 of dissolving the cobalt precipitate in the sulfuric acid solution again, a copper removal step S62 of removing copper by adding sodium hydrogen sulfide, a second extraction step S72 of separating the aqueous solution from which copper is removed into a third filtrate containing cobalt and impurities and a second organic layer
100111 In an embodiment of the present invention, a pH of the filtrate obtained in the second atmospheric pressure heating leaching step may be lower than a pH of the filtrate obtained in the first atmospheric pressure heating leaching step.
[0012] In an embodiment of the present invention, the filtrate obtained in the second atmospheric pressure heating leaching step may be fed to the first atmospheric pressure heating leaching step.
[0013] In an embodiment of the present invention, the first solvent extractant may be bis (2,4,4-trimethylpentyl) phosphinic acid.
[0014] In an embodiment of the present invention, the first extraction step may be carried out at a temperature of 40 degrees C and a pH of greater than 5.0 and less than 5.4.
[0015] In an embodiment of the present invention, the precipitating agent may be sodium fluoride.
[0016] In an embodiment of the present invention, the precipitating agent may be added in an amount of more than 2.0 equivalents and less than 2.4 equivalents of an amount of the magnesium, calcium, or a mixture thereof.
Date Regue/Date Received 2024-03-06 [0017] In an embodiment of the present invention, the neutralizing agent may be a basic material containing sodium.
[0018] In an embodiment of the present invention, after the neutralizing agent is added, the pH
of the first filtrate may be 8 or more at a temperature of 85 degrees C.
[0019] In an embodiment of the present invention, the method may further include: (E-i) a washing step of washing the nickel cake with pure water.
[0020] In an embodiment of the present invention, the sulfide may be sodium hydrogen sulfide (NaSH).
[0021] In an embodiment of the present invention, the sulfide may be added in an amount of more than 1.0 equivalents and less than 1.6 equivalents of an amount of the cobalt and zinc.
[0022] In an embodiment of the present invention, the method may further include: (D-ii) a copper removal step of dissolving the cobalt precipitate in a sulfuric acid solution and then removing copper.
[0023] In an embodiment of the present invention, the copper removal step may be perfoimed by adding sodium hydrogen sulfide (NaSH) in an amount greater than 4.5 equivalents and less than 5.5 equivalents of copper content.
[0024] In an embodiment of the present invention, the method may further include: (E-ii) a second extraction step of separating the copper-removed aqueous solution into a third filtrate containing cobalt and impurities and a second organic layer containing zinc and impurities by adding a second solvent extractant to the copper-removed aqueous solution.
[0025] In an embodiment of the present invention, the second solvent extractant may be D2EHPA (di-(2-ethylhexyl) phosphoric acid).
[0026] In an embodiment of the present invention, the second extraction step may be carried out at a pH of greater than 2.4 and less than 3.2 at a temperature of 40 degrees C.
[0027] In an embodiment of the present invention, the method may further include: (F) a precipitation removal step of precipitating and removing impurities including magnesium by adding a precipitating agent to the third filtrate.
[0028] In an embodiment of the present invention, the method may further include: (G) a target Date Regue/Date Received 2024-03-06 material precipitation step of selectively precipitating a cobalt cake containing cobalt by adding a neutralizing agent to the third filtrate from which the impurities are precipitated and removed.
[0029] In an embodiment of the present invention, after the neutralizing agent is added, the pH
of the third filtrate may be 8 or more at a temperature of 85 degrees C.
[0030] In an embodiment of the present invention, the method may further include: (H) a washing step of washing the cobalt cake with pure water.
[0031] According to the present invention, it is possible to improve the nickel/cobalt recovery rate and reduce the energy consumption by using a two-stage atmospheric pressure heating step.
[0032] In addition, by minimizing the solvent extraction step having a risk of fire and explosion due to the use of an organic solvent in the impurity removal step, it is possible to improve the operating environment and reduce the production cost of a final product.
BRIEF DESCRIPTION OF THE DRAWINGS
[0033] FIG. 1 is a diagram showing a two-stage leaching step and a first extraction step for producing an aqueous solution containing nickel or cobalt according to one embodiment of the present invention.
[0034] FIG. 2 is a diagram showing a precipitation removal step and a target material precipitation step for producing an aqueous solution containing nickel according to one embodiment of the present invention.
[0035] FIG. 3 is a diagram showing an impurity removal step, a copper removal step, a second extraction step, a precipitation removal step, and a target material precipitation step for producing an aqueous solution containing cobalt according to one embodiment of the present invention.
DETAILED DESCRIPTION
[0036] Embodiments of the present disclosure are illustrated for describing the technical spirit of the present disclosure. The scope of the claims according to the present disclosure is not limited to the embodiments described below or to the detailed descriptions of these Date Regue/Date Received 2024-03-06 embodiments.
[0037] The present invention will now be described with reference to the drawings.
[0038] FIG. 1 is a diagram showing a two-stage leaching step S10 and a first extraction step S20 for producing an aqueous solution containing nickel or cobalt according to one embodiment of the present invention. FIG. 2 is a diagram showing a precipitation removal step S31 and a target material precipitation step S32 for producing an aqueous solution containing nickel according to one embodiment of the present invention. FIG. 3 is a diagram showing an impurity removal step S32 and S42, a copper removal step S62, a second extraction step S72, a precipitation removal step S82, and a target material precipitation step S92 for producing an aqueous solution containing cobalt according to one embodiment of the present invention.
[0039] Referring to FIGS. 1 to 3, there may be provided a method for producing an aqueous solution containing nickel or cobalt that can be used for manufacturing a cathode active material of a lithium secondary battery from a mixed hydroxide precipitate (MHP cake) through a series of steps. According to this method, it is possible to improve the operation stability and the purity, and reduce the production cost. Hereinafter, the respective steps will be described in detail with reference to the drawings.
[0040] Firstly, referring to FIG. 1, a leaching step S10 of forming a leachate by performing two-stage atmospheric pressure heating leaching steps on an MHP cake, and a first extraction step S20 of separating the leachate into a first filtrate containing nickel and impurities and a first organic layer containing cobalt and impurities may be performed.
100411 Leaching Step S10 100421 The leaching step S10 is a step of forming a leachate by dissolving an MHP cake in the Rain of hydroxide in an acid solution such as sulfuric acid to ionize the MHP
cake. The leaching step S10 includes a first atmospheric pressure heating leaching step Si! and a second atmospheric pressure heating leaching step S12. The atmospheric pressure heating leaching step is a step of producing an acid solution in an open reactor at a temperature of 100 degrees C
or less, introducing a raw material into the reactor, and leaching valuable metals by a reaction represented by the following Reaction Formula 1. The raw material introduced here may be an Date Regue/Date Received 2024-03-06 MHP cake in the form of hydroxide containing nickel in an amount of 40% by weight.
[0043] Reaction Foimula 1]
[0044] M(OH)2 + H2SO4 MS04 + 2H20 (M is metal such as Ni, Co, or Mg) [0045] The first atmospheric pressure heating leaching step Sll and the second atmospheric pressure heating leaching step S12 may be separately perfoinied in two-stage apparatuses, or may be performed in one pressurization apparatus by changing only the process conditions (e.g., temperature, pressure, or acidity).
[0046] Valuable metals may be leached from the raw material through the first atmospheric pressure heating leaching step S11. For example, valuable metals such as nickel, cobalt, and manganese in the raw material may be leached. In addition, elements such as iron, copper, aluminum, zinc, magnesium, and the like in the raw material may also be leached. The first atmospheric pressure heating leaching step Sll may be performed for about 2 hours at a temperature in the range of 50 degrees C to 70 degrees C and a pH in the range of 2.7 to 3.3.
By satisfying the temperature and the pH, high leaching efficiency can be obtained under optimal conditions.
[0047] In the first atmospheric pressure heating leaching step S11, the solid density of the raw material introduced into the reactor may be 100 g/L or more. For example, the solid density of the raw material may be in the range of 100 g/L to 200 g/L. As used herein, the term "solid density" is defined as the ratio of the mass of the raw material introduced into the pressurization apparatus to the volume of the acid solution previously introduced into the reactor. In other words, the solid density may be the ratio of the mass of the raw material introduced per unit solvent, and may be the mass of the raw material per 1 L of a solvent.
[0048] The filtrate obtained in the first atmospheric pressure heating leaching step S1 1 may be introduced into the first extraction step S20, and the residue may be subsequently treated in the second atmospheric pressure heating leaching step S12.
[0049] In the second atmospheric pressure heating leaching step S12, the leaching residue obtained in the first atmospheric pressure heating leaching step Sll may be leached at a temperature in the range of 80 degrees C to 100 degrees C for about 3 hours.
Other conditions Date Regue/Date Received 2024-03-06 of the second atmospheric pressure heating leaching step S12 may be the same as those of the first atmospheric pressure heating leaching step S11.
[0050] The pH of the filtrate obtained in the second atmospheric pressure heating leaching step S12 may be lower than the pH of the filtrate obtained in the first atmospheric pressure heating leaching step S11. By controlling the pH, the leaching rate in each atmospheric pressure heating leaching step can be increased. Accordingly, the entire amount of the valuable metals contained in the raw material can be leached out. For example, the entire amounts of nickel, cobalt, manganese, iron, copper, aluminum, zinc, and magnesium contained in the raw material can be leached out.
[0051] In one embodiment, the filtrate formed in the second atmospheric pressure heating leaching step S12 may be fed to the first atmospheric pressure heating leaching step S11 as shown in FIG. 1.
[0052] In the case of a commonly used atmospheric pressure leaching method, the reaction time has to be continued for 18 hours or longer to increase the leaching rate of valuable metals. In this case, additional costs are incurred due to the increased use of fuel and steam. The productivity is low because the amount of raw material processed per day is small. However, according to one embodiment of the present invention, by using the two-stage atmospheric pressure heating leaching method, it is possible to improve the recovery rate of nickel and cobalt and reduce the energy consumption. Thus, it is possible to reduce the production cost and improve the productivity.
[0053] The residue generated in the second atmospheric pressure heating leaching step S12 may be discarded as shown in FIG. 1.
[0054] First Extraction step S20 [0055] The first extraction step S20 is a step of selectively separating or extracting nickel from the aqueous solution containing nickel/cobalt (leachate solution) ionized through the two-stage atmospheric pressure heating leaching step by using a first solvent extractant.
[0056] In this regard, the first solvent extractant is not particularly limited as long as the loading rate of nickel is low, and may be, for example, bis(2,4,4-trimethylpentyl) phosphinic acid Date Regue/Date Received 2024-03-06 (Cyanex272).
[0057] When the first solvent extractant is added to the leachate, nickel may be not loaded into the first solvent extractant and may be distributed to the first filtrate (Raffinate). Cobalt and other impurities (Mg, Mn, Zn, etc.) may be separated or extracted by being distributed to an organic layer together with the first solvent extractant. This separation or extraction can occur according to the reactions represented by Reaction Formulae 2 and 3 below. In this regard, the reaction of Reaction Formula 3 is a reaction for maintaining the pH by neutralizing H2SO4 formed by the reaction of Reaction Formula 2.
[0058] [Reaction Founula 2]
[0059] 2HR(org.) + MS04(aq.) MR2(org.) + H2SO4(aq.) (R is Ni etc., and M is Co, Mg, Mn etc.) [0060] [Reaction Foimula 3]
[0061] H2SO4 + Na2CO3 Na2SO4+ H20 + CO2 [0062] The first extraction step may be perfonned at a temperature of 40 degrees C and a pH of greater than 5.0 and less than 5.4. By satisfying the temperature and the pH, it is possible to increase the loading rate of cobalt and impurities, and efficiently separate nickel into the filtrate.
[0063] In one embodiment, the ratio of the first solvent extractant (0) to the aqueous solution (A) can be controlled according to the concentration of the component to be extracted from the solution. For example, the ratio (0:A) of the first solvent extractant (0) to the aqueous solution (A) may range from 0.5:1 to 2:1. For example, the 0:A may be 1.5:1.
[0064] Referring next to FIG. 2, a precipitation removal step S31 of precipitating and removing impurities from the first filtrate that has passed through the first extraction step S20, a target material precipitation step S41 of selectively precipitating a nickel cake containing high-purity nickel, and a final leaching step of producing an aqueous solution containing high-purity nickel may be performed.
[0065] Precipitation Removal Step S31 [0066] The precipitation removal step S31 may be performed to remove impurities such as magnesium, calcium, or a mixture thereof remaining in the first filtrate.
After the precipitation Date Regue/Date Received 2024-03-06 removal step S31, the first filtrate may be fed to the target material precipitation step S41.
[0067] For example, in the precipitation removal step S31, a removing agent may be introduced into the solution. The removing agent is not particularly limited as long as it can react with magnesium or calcium to form a precipitate. The removing agent may be, for example, sodium fluoride (NaF).
[0068] For example, magnesium and calcium may be precipitated as magnesium fluoride or calcium fluoride through a reaction represented by Reaction Foimula 4 below.
[0069] For example, by performing the precipitation removal step S31 for about 2 hours or more at a reaction temperature in the range of 50 degrees C to 70 degrees C, only magnesium and calcium can be separated through selective precipitation while reducing nickel precipitation in the filtrate.
[0070] [Reaction Foimula 4]
[0071] MS04 + 2NaF = MF2 + Na2SO4 (M is Mg or Ca) [0072] In one embodiment, sodium fluoride may be added in an amount greater than 2.0 equivalents (eq) of magnesium, calcium or a mixture thereof. In another embodiment, sodium fluoride may be added in an amount less than 2.4 equivalents (eq) of magnesium, calcium or a mixture thereof.
[0073] Target Material Precipitation Step S41 [0074] In the target material precipitation step S41, a neutralizing agent may be added to the first filtrate after the precipitation removal step S31.
[0075] For example, the neutralizing agent may be a basic material containing sodium. For example, the neutralizing agent may be sodium carbonate (Na2CO3).
[0076] After removing impurities such as magnesium and calcium, in the target material precipitation step S41, nickel may be precipitated in the form of a cake through a reaction indicated by Reaction Formula 5 below.
[0077] [Reaction Foimula 5]
[0078] 3NiSO4 + 3Na2CO3 +2H20 = NiCO3=2Ni(OH)2 + 3Na2SO4 +3CO2 [0079] The target material precipitation step S41 may be performed for 4 hours or more at a pH
Date Regue/Date Received 2024-03-06 of 8 or higher and a temperature in the range of 80 degrees C to 90 degrees C.
[0080] Since nickel can be recovered through the target material precipitation step S41, it is possible to reduce the use of expensive organic solvents that have a risk of explosion and fire.
Thus, it is possible to improve the operational stability and the productivity, and reduce the production costs.
[0081] Although not specifically shown in the drawings, some sodium components may be present in the precipitated nickel cake. Therefore, the water-soluble sodium components can be removed by a washing step using pure water at the rear stage. In this case, the production cost can be reduced by reusing the removed sodium components in producing sodium carbonate (Na2CO3), which is a neutralizing agent.
[0082] Final Leaching Step S51 [0083] The final leaching step S51 is a step of producing an aqueous solution containing high-purity nickel by removing components such as sodium and the like through washing and dissolving the nickel cake in a sulfuric acid solution.
[0084] In the final leaching step S51, the nickel cake may be added to a solution obtained by mixing pure water with sulfuric acid at an acidity of 150 g/L to 200 g/L.
Nickel, cobalt, and trace impurities contained in the nickel cake can be dissolved in the sulfuric acid solution. The sulfuric acid solution and the nickel cake are reacted until the pH becomes 2Ø According to one embodiment, in the final leaching step S51, the reaction may be performed for 4 hours or more at a pH in the range of 1.0 to 3.0 and a temperature in the range of 50 degrees C to 70 degrees C.
[0085] Referring next to FIG. 3, a second filtrate production step S32 of adding a sulfuric acid solution to the first organic layer that has passed through the first extraction step S20, a purification step S42 of precipitating and recovering a cobalt precipitate from the second filtrate and purifying impurities, a step S52 of dissolving the cobalt precipitate in the sulfuric acid solution again, a copper removal step S62 of removing copper by adding sodium hydrogen sulfide, a second extraction step S72 of separating the aqueous solution from which copper is removed into a third filtrate containing cobalt and impurities and a second organic layer
11 Date Regue/Date Received 2024-03-06 containing zinc and impurities, a precipitation removal step S82 of precipitating and removing impurities from the third filtrate, a target material precipitation step S92 of selectively precipitating a cobalt cake containing high-purity cobalt, and a final leaching step of producing an aqueous solution containing high-purity cobalt S102 may be performed.
[0086] Second Filtrate Production Step S32 [0087] The second filtrate production step S32 is a step of stripping cobalt into the sulfuric acid solution by adding a sulfuric acid solution to the first organic layer containing cobalt and impurities.
[0088] Stripping is a process in which a stripping filtrate containing cobalt is produced by reacting sulfuric acid with loaded cobalt, and loaded impurities are recovered with an aqueous solution.
[0089] Purification Step S42 [0090] The purification step S42 is a step of selectively recovering only cobalt from the stripped second filtrate. What is different from the precipitation removal step S31 is that in the purification step S42, cobalt, which is the target material, may be recovered in the form of a precipitate.
[0091] For example, in the purification step S42, a cobalt precipitate may be generated by adding sulfide into the solution. For example, the sulfide may be sodium hydrogen sulfide (NaSH). Cobalt may be precipitated and recovered in the form of sulfide by the reactions represented by the following Reaction Formulae 6 and 7.
[0092] [Reaction Fonnula 61 [0093] CoSO4 + 2NaSH 2CoS + Na2SO4 + H2SO4 [0094] [Reaction Fonnula 71 [0095] H2SO4 + Na2CO3 ¨> Na2SO4 + H20 + CO2 [0096] For example, while maintaining a pH of 4.5 to 5.0 at a reaction temperature in the range of 70 degrees C to 90 degrees C, the purification step S42 may be performed for about 3 hours or more.
[0097] In the above pH range, the solubility of CoS and ZnS is very low, 0.1 mg/L or less, and
[0086] Second Filtrate Production Step S32 [0087] The second filtrate production step S32 is a step of stripping cobalt into the sulfuric acid solution by adding a sulfuric acid solution to the first organic layer containing cobalt and impurities.
[0088] Stripping is a process in which a stripping filtrate containing cobalt is produced by reacting sulfuric acid with loaded cobalt, and loaded impurities are recovered with an aqueous solution.
[0089] Purification Step S42 [0090] The purification step S42 is a step of selectively recovering only cobalt from the stripped second filtrate. What is different from the precipitation removal step S31 is that in the purification step S42, cobalt, which is the target material, may be recovered in the form of a precipitate.
[0091] For example, in the purification step S42, a cobalt precipitate may be generated by adding sulfide into the solution. For example, the sulfide may be sodium hydrogen sulfide (NaSH). Cobalt may be precipitated and recovered in the form of sulfide by the reactions represented by the following Reaction Formulae 6 and 7.
[0092] [Reaction Fonnula 61 [0093] CoSO4 + 2NaSH 2CoS + Na2SO4 + H2SO4 [0094] [Reaction Fonnula 71 [0095] H2SO4 + Na2CO3 ¨> Na2SO4 + H20 + CO2 [0096] For example, while maintaining a pH of 4.5 to 5.0 at a reaction temperature in the range of 70 degrees C to 90 degrees C, the purification step S42 may be performed for about 3 hours or more.
[0097] In the above pH range, the solubility of CoS and ZnS is very low, 0.1 mg/L or less, and
12 Date Regue/Date Received 2024-03-06 the solubility of MgS and MnS is high. Therefore, only cobalt and zinc can be separated through selective precipitation by controlling the pH range, thereby purifying magnesium and manganese.
[0098] In one embodiment, sulfide may be added in an amount greater than 1.0 equivalents and less than 1.6 equivalents of an amount of the cobalt and zinc.
[0099] Sulfuric Acid Solution Production Step S52 [0100] In the sulfuric acid solution production step S52, an aqueous solution is produced by dissolving a precipitate containing cobalt in a sulfuric acid solution.
[0101] For example, the sulfuric acid solution production step S52 may be performed by a reaction represented by the following Reaction Foimula 8.
[0102] [Reaction Formula 81 [0103] CoS + H2SO4 + 1/202 ¨> CoSat + H20 + S
[0104] For example, in the sulfuric acid solution production step S52, the solid density (S/D) of the precipitate in the sulfuric acid solution during the production of the aqueous solution may be 100 g/L or more.
[0105] For example, the sulfuric acid solution production step S52 may be perfoimed at a reaction temperature in the range of 80 degrees C to 100 degrees C for about 20 hours or more.
[0106] Copper Removal Step S62 [0107] The copper removal step S62 is a step of removing copper (Cu) from the solution by adding sodium hydrogen sulfide (NaSH) to the solution. Copper may be precipitated as a copper sulfide (CuS) compound through a reaction indicated by the following Reaction Formula 9.
[0108] [Reaction Fonnula 91 [0109] 2CuSO4 + 2NaSH = 2CuS + Na2SO4 +H2SO4 [0110] Copper sulfide (CuS) can be precipitated at a pH of 1.0 or more. To this end, in the copper removal step S62, the pH of the solution may be maintained at 1.0 to 2.5. In one embodiment, the pH of the solution in the copper removal step S62 may be maintained at 1.0 to 1.5. When the pH in the solution is less than 1.0, it is difficult to remove copper from the
[0098] In one embodiment, sulfide may be added in an amount greater than 1.0 equivalents and less than 1.6 equivalents of an amount of the cobalt and zinc.
[0099] Sulfuric Acid Solution Production Step S52 [0100] In the sulfuric acid solution production step S52, an aqueous solution is produced by dissolving a precipitate containing cobalt in a sulfuric acid solution.
[0101] For example, the sulfuric acid solution production step S52 may be performed by a reaction represented by the following Reaction Foimula 8.
[0102] [Reaction Formula 81 [0103] CoS + H2SO4 + 1/202 ¨> CoSat + H20 + S
[0104] For example, in the sulfuric acid solution production step S52, the solid density (S/D) of the precipitate in the sulfuric acid solution during the production of the aqueous solution may be 100 g/L or more.
[0105] For example, the sulfuric acid solution production step S52 may be perfoimed at a reaction temperature in the range of 80 degrees C to 100 degrees C for about 20 hours or more.
[0106] Copper Removal Step S62 [0107] The copper removal step S62 is a step of removing copper (Cu) from the solution by adding sodium hydrogen sulfide (NaSH) to the solution. Copper may be precipitated as a copper sulfide (CuS) compound through a reaction indicated by the following Reaction Formula 9.
[0108] [Reaction Fonnula 91 [0109] 2CuSO4 + 2NaSH = 2CuS + Na2SO4 +H2SO4 [0110] Copper sulfide (CuS) can be precipitated at a pH of 1.0 or more. To this end, in the copper removal step S62, the pH of the solution may be maintained at 1.0 to 2.5. In one embodiment, the pH of the solution in the copper removal step S62 may be maintained at 1.0 to 1.5. When the pH in the solution is less than 1.0, it is difficult to remove copper from the
13 Date Regue/Date Received 2024-03-06 solution at 20 mg/L or less. When the pH is greater than 2.5, the solubility of cobalt in sulfuric acid is lowered, and cobalt may be lost.
[0111] On the other hand, sodium hydrogen sulfide (NaSH) may be added slowly so that the pH
in the solution does not change rapidly. For example, sodium hydrogen sulfide (NaSH) may be added over about 3 hours while stirring the leachate. Accordingly, it is possible to prevent an increase in the cobalt loss rate due to a rapid increase in pH in some regions of the solution.
[0112] In one embodiment, sodium hydrogen sulfide (NaSH) may be added in an amount greater than 4.5 equivalents (eq) and less than 5.5 equivalents (eq) of copper content. When the addition amount of sodium hydrogen sulfide (NaSH) is 4.5 equivalents (eq) or less, it is difficult to sufficiently remove copper from the solution because the copper removal rate is 95% or less.
When the addition amount of sodium hydrogen sulfide (NaSH) is 5.5 equivalents (eq) or more, the cobalt recovery rate may decrease because the cobalt removal rate is 0.05%
or more.
[0113] By performing the copper removal step S62 for 3 hours or more at a reaction temperature in the range of 50 degrees C to 70 degrees C, it is possible to reduce cobalt precipitation in the filtrate and separate only copper through selective precipitation. Sodium hydrogen sulfide may be a product having a concentration of 30wt% to 70wt%.
[0114] Second Extraction step S72 [0115] The second extraction step S72 is a step of adding a second solvent extractant to the solution and separating the solution into a third filtrate containing cobalt and impurities and a second organic layer containing zinc and impurities.
[0116] In this regard, the second solvent extractant is not particularly limited as long as the cobalt loading rate thereof is low. For example, the second solvent extractant may be D2EHPA
(di-(2-ethylhexyl)phosphoric acid).
[0117] When the second solvent extractant is added to the solution, cobalt may be not loaded into the second solvent extractant and may be distributed to the third filtrate (Raffinate), and zinc, magnesium, manganese, etc. are distributed and separated or extracted to the organic layer together with the second solvent extractant. This separation or extraction may occur through a reaction represented by the following Reaction Formula 10.
[0111] On the other hand, sodium hydrogen sulfide (NaSH) may be added slowly so that the pH
in the solution does not change rapidly. For example, sodium hydrogen sulfide (NaSH) may be added over about 3 hours while stirring the leachate. Accordingly, it is possible to prevent an increase in the cobalt loss rate due to a rapid increase in pH in some regions of the solution.
[0112] In one embodiment, sodium hydrogen sulfide (NaSH) may be added in an amount greater than 4.5 equivalents (eq) and less than 5.5 equivalents (eq) of copper content. When the addition amount of sodium hydrogen sulfide (NaSH) is 4.5 equivalents (eq) or less, it is difficult to sufficiently remove copper from the solution because the copper removal rate is 95% or less.
When the addition amount of sodium hydrogen sulfide (NaSH) is 5.5 equivalents (eq) or more, the cobalt recovery rate may decrease because the cobalt removal rate is 0.05%
or more.
[0113] By performing the copper removal step S62 for 3 hours or more at a reaction temperature in the range of 50 degrees C to 70 degrees C, it is possible to reduce cobalt precipitation in the filtrate and separate only copper through selective precipitation. Sodium hydrogen sulfide may be a product having a concentration of 30wt% to 70wt%.
[0114] Second Extraction step S72 [0115] The second extraction step S72 is a step of adding a second solvent extractant to the solution and separating the solution into a third filtrate containing cobalt and impurities and a second organic layer containing zinc and impurities.
[0116] In this regard, the second solvent extractant is not particularly limited as long as the cobalt loading rate thereof is low. For example, the second solvent extractant may be D2EHPA
(di-(2-ethylhexyl)phosphoric acid).
[0117] When the second solvent extractant is added to the solution, cobalt may be not loaded into the second solvent extractant and may be distributed to the third filtrate (Raffinate), and zinc, magnesium, manganese, etc. are distributed and separated or extracted to the organic layer together with the second solvent extractant. This separation or extraction may occur through a reaction represented by the following Reaction Formula 10.
14 Date Regue/Date Received 2024-03-06 [0118] [Reaction Formula 10]
[0119] 2HR(org.) + ZnSO4(aq.) ¨> ZnR2(org.) + H2SO4(aq.) (R is Co, etc.) [0120] The second extraction step S72 may be performed for about 10 minutes or longer at a pH
of greater than 2.4 and less than 3.2 and a temperature of 40 degrees C. By satisfying the pH
range under the temperature condition, it is possible to increase the loading rate of impurities such as zinc and the like, lower the loading rate of cobalt, and efficiently separate cobalt into the filtrate.
[0121] In one embodiment, the ratio of the second solvent extractant (0) to the aqueous solution (A) can be controlled according to the concentration of the component to be extracted in the solution. For example, the ratio (0:A) of the second solvent extractant (0) to the aqueous solution (A) may range from 0.5:1 to 2:1. For example, the 0:A can be 1.5:1.
[0122] Precipitation Removal Step S82 [0123] The precipitation removal step S82 may be performed to remove impurities such as magnesium and the like remaining in the third filtrate. After the precipitation removal step S82, the third filtrate may be fed to the target material precipitation step S92.
[0124] Details of the precipitation removal step S82 may be understood by referring to the description of the precipitation removal step S31.
[0125] Target Material Precipitation Step 592 [0126] In the target material precipitation step S92, a neutralizing agent may be added to the third filtrate after the precipitation removal step S82.
[0127] For example, the neutralizing agent may be a basic material containing sodium. For example, the neutralizing agent may be sodium carbonate (Na2CO3).
[0128] After removing impurities such as magnesium and the like, nickel may be precipitated in the form of a cake through a reaction represented by the following Reaction Formula 11 in the target material precipitation step S41.
[0129] [Reaction Foimula 11]
[0130] 3CoSO4 + 3Na2CO3 +2H20 = CoCO3-2Co(OH)2 + 3Na2SO4 +3CO2 [0131] The target material precipitation step S92 may be performed for 4 hours or more at a pH
Date Regue/Date Received 2024-03-06 of 8 or higher and a temperature in the range of 80 degrees C to 90 degrees C.
[0132] Since cobalt can be recovered through the target material precipitation step S92, it is possible to reduce the use of expensive organic solvents that have a risk of explosion and fire.
Thus, it is possible to improve the operational stability and the productivity, and reduce the production costs.
[0133] Although not specifically shown in the drawings, some sodium components may be present in the precipitated cobalt cake. Therefore, the water-soluble sodium components can be removed by a washing step using pure water at the rear stage. In this case, the production cost can be reduced by reusing the removed sodium components in producing sodium carbonate (Na2CO3), which is a neutralizing agent.
[0134] Final Leaching Step S102 [0135] The final leaching step S102 is a step of producing an aqueous solution containing high-purity cobalt by removing components such as sodium and the like through washing and dissolving the cobalt cake in a sulfuric acid solution.
[0136] Details of the final leaching step S102 may be understood by referring to the above description of the final leaching step S51.
[0137] Experimental Example [0138] (1) Quality of the MHP cake raw material used in the experiment [0139] [Table 1]
Ni Co Mg Mn Zn Content (wt%) 38.0 3.80 1.40 6.15 0.90 [0140] * The content not shown in the table is impurities (mostly present with hydroxyl groups attached thereto) (2) Metal content in the leaching filtrate after the leaching step including the two-stage atmospheric pressure heating leaching step [0141] [Table 21 Ni Co Mg Mn Zn Content (g/L) 100.1 10.3 5.11 9.87 2.33 [0142] Comparing Tables 1 and 2, it can be seen that the nickel and cobalt contents in the Date Regue/Date Received 2024-03-06 leaching filtrate subjected to the two-stage atmospheric pressure heating leaching step are increased. (3) Comparison of cobalt contents in the organic layer according to the pH
conditions in the extraction step [0143] Loading rates of the respective components in the organic layer at pH
5.0, 5.2, and 5.4 were compared in order to examine the optimal pH conditions for separating nickel into an aqueous filtrate (Raffinate) by loading cobalt and impurities (Mg, Mn, Zn, etc.) into the organic layer using 30%Cyanex272. The reaction was carried out at 40 degrees C for 10 minutes, and the ratio of the organic layer to the aqueous solution was 1.5: 1. The loading rate was expressed as a relative ratio of the content of each component present in the organic layer based on the content of each component present in the leachate.
[0144] [Table 31 pH 5.0 Ni Co Mg Mn Zn Loading rate (%) 1.18 94.8 68.2 96.3 99.9 pH 5.2 Ni Co Mg Mn Zn Loading rate (%) 1.20 97.5 70.0 99.0 99.9 pH 5.4 Ni Co Mg Mn Zn Loading rate (%) 1.55 97.8 70.5 99.2 99.9 [0145] Referring to Table 3, it can be seen that the difference between the contents of Co and Ni loaded in the organic layer is largest at pH 5.2, and the separation of Co and Ni occurs best at the pH of 5.2.
[0146] In the case of pH 5.0, the content of Ni loaded in the organic layer was small, but the Co loading was relatively poor. In the case of pH 5.4, the Co loading was excellent, but the separation of Ni was relatively poor.
[0147] (4) Comparison of the content of impurities (Mg and Ca) in the filtrate according to the addition amount of sodium fluoride in the precipitation removal step Date Regue/Date Received 2024-03-06 [0148] In order to examine the optimal addition amount of sodium fluoride (NaF) for precipitating and removing impurities (Mg and Ca) in the filtrate, the sodium fluoride (NaF) was added at 2.0, 2.2, and 2.4 equivalents of Mg and Ca contents in the filtrate.
The contents of impurities (Mg and Ca) in the filtrate were compared. The reaction was carried out for 2 hours at a temperature of 60 degrees C.
[0149] [Table 41 Filtrate 2.0 Equivalent 2.2 Equivalent 2.4 Equivalent Added Added Added Mg Ca Mg Ca Mg Ca Mg Ca Content mg/L 1,024 184 252.2 68.2 204.8 55.1 205.0 54.9 [0150] Referring to Table 4, it can be seen that the sum of the contents of Mg and Ca in the filtrate is smallest when sodium fluoride (NaF) is added at 2.2 equivalents.
(5) Comparison of metal contents (Co, Cu, Zn, Mn, and Mg) in the cobalt cake according to the addition amount of sodium hydrogen sulfide (NaSH) in the impurity removal step [0151] In order to examine the optimal conditions for stripping cobalt loaded by Cyanex272 in the organic layer with a sulfuric acid solution and then precipitating and recovering cobalt in the form of sulfide using sodium hydrogen sulfide (NaSH), the sodium hydrogen sulfide (NaSH) was added at 1.0, 1.3, and 1.6 equivalents of cobalt and zinc contents, and the precipitated cake contents were compared. The reaction was carried out for 3 hours at a temperature of 85 degrees C and a pH of 4.5 to 5Ø
[0152] [Table 51 1.0 Equivalent Added Co Cu Zn Mn Mg Content (%) 35.2 0.08 7.76 2.82 0.12 1.3 Equivalent Added Co Cu Zn Mn Mg Content (%) 37.0 0.04 8.76 2.59 0.05 Date Regue/Date Received 2024-03-06 1.6 Equivalent Added Co Cu Zn Mn Mg Content (%) 37.0 0.05 8.72 2.52 0.03 [0153] Referring to Table 5, it can be seen that the cobalt content in the cake is high when NaSH
is added at 1.3 equivalents, and the cobalt content does not increase any more even when NaSH
is added in excess of 1.3 equivalents.
[0154] (6) Comparison of copper removal rates according to the addition amount of sodium hydrogen sulfide (NaSH) in the copper removal step [0155] In order to examine the optimal conditions for precipitating and removing copper in the form of CuS by adding NaSH to the aqueous solution containing cobalt after dissolving the cobalt precipitate in a sulfuric acid solution, NaSH was added at 4.5, 5.0, and 5.5 equivalents of the copper content, and the removal rates of copper were compared. The reaction was carried out for 3 hours at a temperature of 60 degrees C and a pH of 1Ø The removal rates were indicated by comparing the contents of respective components present in the aqueous solution before and after adding NaSH.
[0156] [Table 61 4.5 Equivalent Added Co Cu Zn Mn Mg Removal rate (%) 0.04 94.2 0.03 1.00 1.92 5.0 Equivalent Added Co Cu Zn Mn Mg Removal rate (%) 0.04 96.5 0.01 1.01 2.00 5.5 Equivalent Added Co Cu Zn Mn Mg Removal rate (%) 0.05 96.3 0.02 1.08 2.21 [0157] Referring to Table 6, it can be seen that the removal rate of Cu is highest when NaSH is added at 5.0 equivalents.
Date Regue/Date Received 2024-03-06 [0158] (7) Comparison of cobalt contents in the organic layer according to pH
conditions in the extraction step [0159] In order to examine the optimal pH conditions for loading zinc in the aqueous solution into the organic layer and separating zinc by using 30% D2EHPA as a solvent extractant for the aqueous solution containing cobalt from which cobalt has been precipitated and removed, the loading rates of the respective components at pHs of 2.4, 2.8, and 3.2 were compared. The reaction was carried out at a temperature of 40 degrees C for 10 minutes. The ratio of the organic layer to the aqueous solution was 1.5: 1.
[0160] [Table 71 pH 2.4 Co Zn Mn Mg Loading rate (%) 0.02 99.6 68.2 30.8 pH 2.8 Co Zn Mn Mg Loading rate (%) 0.10 100 75.0 40.0 pH 3.2 Co Zn Mn Mg Loading rate (%) 0.38 100 80.2 43.3 [0161] Referring to Table 7, it can be seen that the difference between the contents of Zn and Co loaded in the organic layer is largest under the pH 2.8 condition, and the separation of Co and Zn occurs best under the pH 2.8 condition.
[0162] In the case of pH 2.4, the content of Co loaded in the organic layer was small, but the Zn loading was relatively poor. In the case of pH 3.2, the a loading was excellent, but the separation of Co was relatively poor.
[0163] (8) Metal contents in the aqueous solution containing nickel/cobalt that have undergone the final washing step to remove impurities [0164] [Table 81 Metal Content in Final Aqueous Solution Containing Nickel After Impurity Removal Date Regue/Date Received 2024-03-06 Ni(g/L) Co Mg Mn Zn Content (mg/L) 131.3 17.9 18.9 2.87 2.88 [0165] [Table 9]
Metal Content in Final Aqueous Solution Containing Cobalt After Impurity Removal Co(g/L) Cu Zn Mn Mg Content (mg/L) 110.6 3.63 3.38 12.0 11.4 [0166] Comparing Table 2 and Tables 8 and 9 together, it can be confirmed that the purity of the aqueous solution containing nickel/cobalt subjected to the steps of the present invention is increased. Although the embodiments of the present disclosure have been described with reference to the accompanying drawings, those skilled in the art to which the present disclosure pertains will be able to understand that the embodiments can be implemented in other specific forms without changing the technical spirit or essential features of the present disclosure.
[0167] Therefore, it should be understood that the embodiments described above are exemplary and not limitative in all respects. The scope of the present disclosure is defined by the claims rather than the detailed description. It should be construed that all changes or modified forms derived from the meaning and scope of the claims and equivalent concepts thereof are included in the scope of the present disclosure.
Date Regue/Date Received 2024-03-06
[0119] 2HR(org.) + ZnSO4(aq.) ¨> ZnR2(org.) + H2SO4(aq.) (R is Co, etc.) [0120] The second extraction step S72 may be performed for about 10 minutes or longer at a pH
of greater than 2.4 and less than 3.2 and a temperature of 40 degrees C. By satisfying the pH
range under the temperature condition, it is possible to increase the loading rate of impurities such as zinc and the like, lower the loading rate of cobalt, and efficiently separate cobalt into the filtrate.
[0121] In one embodiment, the ratio of the second solvent extractant (0) to the aqueous solution (A) can be controlled according to the concentration of the component to be extracted in the solution. For example, the ratio (0:A) of the second solvent extractant (0) to the aqueous solution (A) may range from 0.5:1 to 2:1. For example, the 0:A can be 1.5:1.
[0122] Precipitation Removal Step S82 [0123] The precipitation removal step S82 may be performed to remove impurities such as magnesium and the like remaining in the third filtrate. After the precipitation removal step S82, the third filtrate may be fed to the target material precipitation step S92.
[0124] Details of the precipitation removal step S82 may be understood by referring to the description of the precipitation removal step S31.
[0125] Target Material Precipitation Step 592 [0126] In the target material precipitation step S92, a neutralizing agent may be added to the third filtrate after the precipitation removal step S82.
[0127] For example, the neutralizing agent may be a basic material containing sodium. For example, the neutralizing agent may be sodium carbonate (Na2CO3).
[0128] After removing impurities such as magnesium and the like, nickel may be precipitated in the form of a cake through a reaction represented by the following Reaction Formula 11 in the target material precipitation step S41.
[0129] [Reaction Foimula 11]
[0130] 3CoSO4 + 3Na2CO3 +2H20 = CoCO3-2Co(OH)2 + 3Na2SO4 +3CO2 [0131] The target material precipitation step S92 may be performed for 4 hours or more at a pH
Date Regue/Date Received 2024-03-06 of 8 or higher and a temperature in the range of 80 degrees C to 90 degrees C.
[0132] Since cobalt can be recovered through the target material precipitation step S92, it is possible to reduce the use of expensive organic solvents that have a risk of explosion and fire.
Thus, it is possible to improve the operational stability and the productivity, and reduce the production costs.
[0133] Although not specifically shown in the drawings, some sodium components may be present in the precipitated cobalt cake. Therefore, the water-soluble sodium components can be removed by a washing step using pure water at the rear stage. In this case, the production cost can be reduced by reusing the removed sodium components in producing sodium carbonate (Na2CO3), which is a neutralizing agent.
[0134] Final Leaching Step S102 [0135] The final leaching step S102 is a step of producing an aqueous solution containing high-purity cobalt by removing components such as sodium and the like through washing and dissolving the cobalt cake in a sulfuric acid solution.
[0136] Details of the final leaching step S102 may be understood by referring to the above description of the final leaching step S51.
[0137] Experimental Example [0138] (1) Quality of the MHP cake raw material used in the experiment [0139] [Table 1]
Ni Co Mg Mn Zn Content (wt%) 38.0 3.80 1.40 6.15 0.90 [0140] * The content not shown in the table is impurities (mostly present with hydroxyl groups attached thereto) (2) Metal content in the leaching filtrate after the leaching step including the two-stage atmospheric pressure heating leaching step [0141] [Table 21 Ni Co Mg Mn Zn Content (g/L) 100.1 10.3 5.11 9.87 2.33 [0142] Comparing Tables 1 and 2, it can be seen that the nickel and cobalt contents in the Date Regue/Date Received 2024-03-06 leaching filtrate subjected to the two-stage atmospheric pressure heating leaching step are increased. (3) Comparison of cobalt contents in the organic layer according to the pH
conditions in the extraction step [0143] Loading rates of the respective components in the organic layer at pH
5.0, 5.2, and 5.4 were compared in order to examine the optimal pH conditions for separating nickel into an aqueous filtrate (Raffinate) by loading cobalt and impurities (Mg, Mn, Zn, etc.) into the organic layer using 30%Cyanex272. The reaction was carried out at 40 degrees C for 10 minutes, and the ratio of the organic layer to the aqueous solution was 1.5: 1. The loading rate was expressed as a relative ratio of the content of each component present in the organic layer based on the content of each component present in the leachate.
[0144] [Table 31 pH 5.0 Ni Co Mg Mn Zn Loading rate (%) 1.18 94.8 68.2 96.3 99.9 pH 5.2 Ni Co Mg Mn Zn Loading rate (%) 1.20 97.5 70.0 99.0 99.9 pH 5.4 Ni Co Mg Mn Zn Loading rate (%) 1.55 97.8 70.5 99.2 99.9 [0145] Referring to Table 3, it can be seen that the difference between the contents of Co and Ni loaded in the organic layer is largest at pH 5.2, and the separation of Co and Ni occurs best at the pH of 5.2.
[0146] In the case of pH 5.0, the content of Ni loaded in the organic layer was small, but the Co loading was relatively poor. In the case of pH 5.4, the Co loading was excellent, but the separation of Ni was relatively poor.
[0147] (4) Comparison of the content of impurities (Mg and Ca) in the filtrate according to the addition amount of sodium fluoride in the precipitation removal step Date Regue/Date Received 2024-03-06 [0148] In order to examine the optimal addition amount of sodium fluoride (NaF) for precipitating and removing impurities (Mg and Ca) in the filtrate, the sodium fluoride (NaF) was added at 2.0, 2.2, and 2.4 equivalents of Mg and Ca contents in the filtrate.
The contents of impurities (Mg and Ca) in the filtrate were compared. The reaction was carried out for 2 hours at a temperature of 60 degrees C.
[0149] [Table 41 Filtrate 2.0 Equivalent 2.2 Equivalent 2.4 Equivalent Added Added Added Mg Ca Mg Ca Mg Ca Mg Ca Content mg/L 1,024 184 252.2 68.2 204.8 55.1 205.0 54.9 [0150] Referring to Table 4, it can be seen that the sum of the contents of Mg and Ca in the filtrate is smallest when sodium fluoride (NaF) is added at 2.2 equivalents.
(5) Comparison of metal contents (Co, Cu, Zn, Mn, and Mg) in the cobalt cake according to the addition amount of sodium hydrogen sulfide (NaSH) in the impurity removal step [0151] In order to examine the optimal conditions for stripping cobalt loaded by Cyanex272 in the organic layer with a sulfuric acid solution and then precipitating and recovering cobalt in the form of sulfide using sodium hydrogen sulfide (NaSH), the sodium hydrogen sulfide (NaSH) was added at 1.0, 1.3, and 1.6 equivalents of cobalt and zinc contents, and the precipitated cake contents were compared. The reaction was carried out for 3 hours at a temperature of 85 degrees C and a pH of 4.5 to 5Ø
[0152] [Table 51 1.0 Equivalent Added Co Cu Zn Mn Mg Content (%) 35.2 0.08 7.76 2.82 0.12 1.3 Equivalent Added Co Cu Zn Mn Mg Content (%) 37.0 0.04 8.76 2.59 0.05 Date Regue/Date Received 2024-03-06 1.6 Equivalent Added Co Cu Zn Mn Mg Content (%) 37.0 0.05 8.72 2.52 0.03 [0153] Referring to Table 5, it can be seen that the cobalt content in the cake is high when NaSH
is added at 1.3 equivalents, and the cobalt content does not increase any more even when NaSH
is added in excess of 1.3 equivalents.
[0154] (6) Comparison of copper removal rates according to the addition amount of sodium hydrogen sulfide (NaSH) in the copper removal step [0155] In order to examine the optimal conditions for precipitating and removing copper in the form of CuS by adding NaSH to the aqueous solution containing cobalt after dissolving the cobalt precipitate in a sulfuric acid solution, NaSH was added at 4.5, 5.0, and 5.5 equivalents of the copper content, and the removal rates of copper were compared. The reaction was carried out for 3 hours at a temperature of 60 degrees C and a pH of 1Ø The removal rates were indicated by comparing the contents of respective components present in the aqueous solution before and after adding NaSH.
[0156] [Table 61 4.5 Equivalent Added Co Cu Zn Mn Mg Removal rate (%) 0.04 94.2 0.03 1.00 1.92 5.0 Equivalent Added Co Cu Zn Mn Mg Removal rate (%) 0.04 96.5 0.01 1.01 2.00 5.5 Equivalent Added Co Cu Zn Mn Mg Removal rate (%) 0.05 96.3 0.02 1.08 2.21 [0157] Referring to Table 6, it can be seen that the removal rate of Cu is highest when NaSH is added at 5.0 equivalents.
Date Regue/Date Received 2024-03-06 [0158] (7) Comparison of cobalt contents in the organic layer according to pH
conditions in the extraction step [0159] In order to examine the optimal pH conditions for loading zinc in the aqueous solution into the organic layer and separating zinc by using 30% D2EHPA as a solvent extractant for the aqueous solution containing cobalt from which cobalt has been precipitated and removed, the loading rates of the respective components at pHs of 2.4, 2.8, and 3.2 were compared. The reaction was carried out at a temperature of 40 degrees C for 10 minutes. The ratio of the organic layer to the aqueous solution was 1.5: 1.
[0160] [Table 71 pH 2.4 Co Zn Mn Mg Loading rate (%) 0.02 99.6 68.2 30.8 pH 2.8 Co Zn Mn Mg Loading rate (%) 0.10 100 75.0 40.0 pH 3.2 Co Zn Mn Mg Loading rate (%) 0.38 100 80.2 43.3 [0161] Referring to Table 7, it can be seen that the difference between the contents of Zn and Co loaded in the organic layer is largest under the pH 2.8 condition, and the separation of Co and Zn occurs best under the pH 2.8 condition.
[0162] In the case of pH 2.4, the content of Co loaded in the organic layer was small, but the Zn loading was relatively poor. In the case of pH 3.2, the a loading was excellent, but the separation of Co was relatively poor.
[0163] (8) Metal contents in the aqueous solution containing nickel/cobalt that have undergone the final washing step to remove impurities [0164] [Table 81 Metal Content in Final Aqueous Solution Containing Nickel After Impurity Removal Date Regue/Date Received 2024-03-06 Ni(g/L) Co Mg Mn Zn Content (mg/L) 131.3 17.9 18.9 2.87 2.88 [0165] [Table 9]
Metal Content in Final Aqueous Solution Containing Cobalt After Impurity Removal Co(g/L) Cu Zn Mn Mg Content (mg/L) 110.6 3.63 3.38 12.0 11.4 [0166] Comparing Table 2 and Tables 8 and 9 together, it can be confirmed that the purity of the aqueous solution containing nickel/cobalt subjected to the steps of the present invention is increased. Although the embodiments of the present disclosure have been described with reference to the accompanying drawings, those skilled in the art to which the present disclosure pertains will be able to understand that the embodiments can be implemented in other specific forms without changing the technical spirit or essential features of the present disclosure.
[0167] Therefore, it should be understood that the embodiments described above are exemplary and not limitative in all respects. The scope of the present disclosure is defined by the claims rather than the detailed description. It should be construed that all changes or modified forms derived from the meaning and scope of the claims and equivalent concepts thereof are included in the scope of the present disclosure.
Date Regue/Date Received 2024-03-06
Claims (22)
1. A method for producing an aqueous solution containing nickel or cobalt comprising:
(A) a leaching step, which includes a first atmospheric pressure heating leaching step and a second atmospheric pressure heating leaching step, in which a raw material is heated and leached under an atmospheric pressure to form a leachate solution containing nickel, cobalt, and impurities;
(B) a first extraction step of separating the leachate solution into a first filtrate containing nickel and impurities and a first organic layer containing cobalt and impurities by adding a first solvent extractant to the leachate solution;
(C-i) a precipitation removal step of precipitating and removing impurities including magnesium, calcium, or a mixture thereof by adding a precipitating agent to the first filtrate; and (D-i) a target material precipitation step of selectively precipitating a nickel cake containing nickel by adding a neutralizing agent to the first filtrate from which the impurities are precipitated and removed.
(A) a leaching step, which includes a first atmospheric pressure heating leaching step and a second atmospheric pressure heating leaching step, in which a raw material is heated and leached under an atmospheric pressure to form a leachate solution containing nickel, cobalt, and impurities;
(B) a first extraction step of separating the leachate solution into a first filtrate containing nickel and impurities and a first organic layer containing cobalt and impurities by adding a first solvent extractant to the leachate solution;
(C-i) a precipitation removal step of precipitating and removing impurities including magnesium, calcium, or a mixture thereof by adding a precipitating agent to the first filtrate; and (D-i) a target material precipitation step of selectively precipitating a nickel cake containing nickel by adding a neutralizing agent to the first filtrate from which the impurities are precipitated and removed.
2. A method for producing an aqueous solution containing nickel or cobalt comprising:
(A) a leaching step, which includes a first atmospheric pressure heating leaching step and a second atmospheric pressure heating leaching step, in which a raw material is heated and leached under an atmospheric pressure to form a leachate solution containing nickel, cobalt, and impurities;
(B) a first extraction step of separating the leachate solution into a first filtrate containing nickel and impurities and a first organic layer containing cobalt and impurities by adding a first solvent extractant to the leachate solution; and (C-ii) a purification step of removing impurities including magnesium, manganese, zinc, copper, or mixtures thereof by adding a sulfuric acid solution to the first organic layer to produce a second filtrate, and adding sulfide to the second filtrate to precipitate and recover a cobalt Date Regue/Date Received 2024-03-06 precipitate.
(A) a leaching step, which includes a first atmospheric pressure heating leaching step and a second atmospheric pressure heating leaching step, in which a raw material is heated and leached under an atmospheric pressure to form a leachate solution containing nickel, cobalt, and impurities;
(B) a first extraction step of separating the leachate solution into a first filtrate containing nickel and impurities and a first organic layer containing cobalt and impurities by adding a first solvent extractant to the leachate solution; and (C-ii) a purification step of removing impurities including magnesium, manganese, zinc, copper, or mixtures thereof by adding a sulfuric acid solution to the first organic layer to produce a second filtrate, and adding sulfide to the second filtrate to precipitate and recover a cobalt Date Regue/Date Received 2024-03-06 precipitate.
3. The method of Claim 1 or 2, wherein a pH of a filtrate obtained in the second atmospheric pressure heating leaching step is lower than a pH of the filtrate obtained in the first atmospheric pressure heating leaching step.
4. The method of Claim 1 or 2, wherein a filtrate obtained in the second atmospheric pressure heating leaching step is fed to the first atmospheric pressure heating leaching step.
5. The method of Claim 1 or 2, wherein the first solvent extractant is bis (2,4,4-trimethylpentyl) phosphinic acid.
6. The method of Claim 1 or 2, wherein the first extraction step is carried out at a temperature of 40 degrees C and a pH of greater than 5.0 and less than 5.4.
7. The method of Claim 1, wherein the precipitating agent is sodium fluoride.
8. The method of Claim 1, wherein the precipitating agent is added in an amount of more than 2.0 equivalents and less than 2.4 equivalents of an amount of the magnesium, calcium, or a mixture thereof.
9. The method of Claim 1, wherein the neutralizing agent is a basic material containing sodium.
10. The method of Claim 1, wherein after the neutralizing agent is added, a pH of the first filtrate is 8 or more at a temperature of 85 degrees C.
Date Regue/Date Received 2024-03-06
Date Regue/Date Received 2024-03-06
11. The method of Claim 1, further comprising:
(E-i) a washing step of washing the nickel cake with pure water.
(E-i) a washing step of washing the nickel cake with pure water.
12. The method of Claim 2, wherein the sulfide is sodium hydrogen sulfide (NaSH).
13. The method of Claim 2, wherein the sulfide is added in an amount of more than 1.0 equivalents and less than 1.6 equivalents of an amount of the cobalt and zinc.
14. The method of Claim 2, further comprising:
(D-ii) a copper removal step of dissolving the cobalt precipitate in a sulfuric acid solution and then removing copper.
(D-ii) a copper removal step of dissolving the cobalt precipitate in a sulfuric acid solution and then removing copper.
15. The method of Claim 13, wherein the copper removal step is performed by adding sodium hydrogen sulfide (NaSH) in an amount greater than 4.5 equivalents and less than 5.5 equivalents of an amount of the copper.
16. The method of Claim 14, further comprising:
(E-ii) a second extraction step of separating the copper-removed aqueous solution into a third filtrate containing cobalt and impurities and a second organic layer containing zinc and impurities by adding a second solvent extractant to the copper-removed aqueous solution.
(E-ii) a second extraction step of separating the copper-removed aqueous solution into a third filtrate containing cobalt and impurities and a second organic layer containing zinc and impurities by adding a second solvent extractant to the copper-removed aqueous solution.
17. The method of Claim 16, wherein the second solvent extractant is D2EHPA
(di-(2-ethylhexyl) phosphoric acid).
(di-(2-ethylhexyl) phosphoric acid).
18. The method of Claim 16, wherein the second extraction step is carried out at a pH of greater than 2.4 and less than 3.2 at a temperature of 40 degrees C.
Date Regue/Date Received 2024-03-06
Date Regue/Date Received 2024-03-06
19. The method of Claim 16, further comprising:
(F) a precipitation removal step of precipitating and removing impurities including magnesium by adding a precipitating agent to the third filtrate.
(F) a precipitation removal step of precipitating and removing impurities including magnesium by adding a precipitating agent to the third filtrate.
20. The method of Claim 19, further comprising:
(G) a target material precipitation step of selectively precipitating a cobalt cake containing cobalt by adding a neutralizing agent to the third filtrate from which the impurities are precipitated and removed.
(G) a target material precipitation step of selectively precipitating a cobalt cake containing cobalt by adding a neutralizing agent to the third filtrate from which the impurities are precipitated and removed.
21. The method of Claim 20, wherein after the neutralizing agent is added, a pH of the third filtrate is 8 or more at a temperature of 85 degrees C.
22. The method of Claim 20, further comprising:
(H) a washing step of washing the cobalt cake with pure water.
Date Regue/Date Received 2024-03-06
(H) a washing step of washing the cobalt cake with pure water.
Date Regue/Date Received 2024-03-06
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
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KR10-2023-0010613 | 2023-01-27 |
Publications (1)
Publication Number | Publication Date |
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CA3211609C true CA3211609C (en) | 2024-05-28 |
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