Method for recycling cobalt intermediate product

Abstract

The invention provides a method for recycling a cobalt intermediate product, which comprises the following steps: washing the cobalt intermediate product to obtain the washed cobalt intermediate product; the washed cobalt intermediate product is subjected to reduction leaching, a leaching solution is obtained, and acid adopted for reduction leaching comprises hydrochloric acid and / or nitric acid; sequentially carrying out iron and aluminum removal, calcium and magnesium removal, copper and zinc removal and fluorine removal on the lixivium to obtain fluorine-removed liquid; and adding any one or a combination of at least two of nickel salt, cobalt salt or manganese salt into the fluorine-removed liquid, and finally carrying out spray pyrolysis to obtain the nickel-cobalt-manganese ternary precursor. According to the method, sulfate radicals in a cobalt intermediate product are removed through washing, then a ternary solution is obtained through hydrochloric acid / nitric acid leaching, impurity removal and the like, then corresponding nickel-cobalt-manganese salt is supplemented according to the size of a precursor, finally, the ternary precursor is prepared through direct spray drying, volatile acid generated through pyrolysis is recycled to a leaching section, and the content of the cobalt in the cobalt intermediate product is reduced. And therefore, the cost of recovering and treating the cobalt intermediate product can be greatly reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of hydrometallurgy and relates to a method for recycling and processing cobalt intermediates. Background Art

[0002] Cobalt intermediates are the main raw materials for the production of high-purity cobalt sulfate or cobalt chloride. The mainstream processing process is sulfuric acid leaching - P204 impurity removal - P507 enrichment - finished product liquid purification. This process involves full leaching and extraction of metallic cobalt, which consumes a large amount of liquid alkali and produces a large amount of wastewater. The cost of cobalt processing throughout the entire process is as high as 13,000 to 15,000 yuan per ton of gold.

[0003] For example, CN119430290A discloses a method for preparing a precursor sulfate solution using a nickel hydroxide cobalt intermediate and its application, the method comprising: acid leaching the intermediate and adding a flocculant to obtain a cobalt-nickel-manganese mixed solution and a manganese slag; extracting the cobalt-nickel-manganese mixed solution with P507-C272, and extracting the loaded organic phase to obtain a crude manganese sulfate solution; removing impurities from the raffinate with P204, recovering cobalt with P507 to obtain a cobalt sulfate solution, and then separating nickel and magnesium with C272 to obtain a nickel sulfate solution; and reducing and leaching the manganese slag to obtain a reduced The leachate is then mixed with a sodium carbonate solution to remove iron to obtain a de-ironized solution; the de-ironized solution is mixed with a crude manganese sulfate solution to remove calcium and magnesium to obtain a de-calcified and magnesiumized solution; the de-calcified and magnesiumized solution is mixed with an aluminum source to remove fluoride to obtain a de-fluorinated solution; the de-fluorinated solution is mixed with sulfides to remove copper and zinc, and then an alkaline solution is added to obtain a de-weighted solution, which is treated with a modified resin to obtain a refined manganese sulfate solution. However, in this process, high-valent manganese is not fully extracted, and nickel, cobalt, and low-valent manganese are obtained by using conventional P507 and P204 full extraction processes to obtain corresponding sulfates, respectively, without significantly reducing costs.

[0004] For example, CN117684003A discloses a low-cost method for smelting nickel cobalt hydroxide intermediates, which includes the following steps: (1) sulfuric acid leaching; (2) impurity removal-extraction-evaporation crystallization; (3) reducing agent reduction; (4) iron and aluminum removal; (5) P204 selective extraction of zinc; (6) calcium and magnesium removal; (7) fluorine removal; and (8) preparation of a ternary precursor. The process uses sulfuric acid to leach the nickel cobalt hydroxide intermediate in two stages. The first stage leachate is subjected to a conventional full extraction separation process to obtain the corresponding sulfate. The second stage reduction leachate is subjected to a chemical and extraction impurity removal process to obtain a ternary sulfate solution. The process requires two sets of leaching-impurity removal-extraction systems to implement, and the process is relatively complex.

[0005] Therefore, existing technologies all use sulfuric acid leaching to obtain a leachate, employing a traditional step-by-step extraction process to obtain a single, pure sulfate solution. This solution is then prepared into a ternary solution for precipitation reaction during precursor synthesis. This complex process also produces large amounts of raffinate wastewater and a large amount of sodium sulfate. Furthermore, the current industry-wide semi-extraction process for nickel hydroxide intermediates has been industrialized, significantly reducing production costs. However, cobalt intermediates, due to their nickel and magnesium content, still require a full extraction process, resulting in high process costs. Summary of the Invention

[0006] The object of the present invention is to provide a method for recycling and treating a cobalt intermediate. The method first removes sulfate from the cobalt intermediate by washing, then uses hydrochloric acid / nitric acid for leaching and impurity removal to obtain a ternary liquid, then adds corresponding nickel, cobalt and manganese salts according to the precursor model, and finally directly spray-dries to obtain a ternary precursor. The volatile acid generated by pyrolysis is reused in the leaching stage, thereby significantly reducing the cost of recycling and treating the cobalt intermediate.

[0007] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0008] The present invention provides a method for recovering and processing a cobalt intermediate, the method comprising the following steps:

[0009] (1) washing the cobalt intermediate product to obtain a washed cobalt intermediate product;

[0010] (2) subjecting the washed cobalt intermediate product of step (1) to reduction leaching to obtain a leachate, wherein the acid used in the reduction leaching comprises hydrochloric acid and / or nitric acid;

[0011] (3) removing iron and aluminum, calcium and magnesium, copper and zinc, and fluorine from the leachate in step (2) to obtain a defluorinated solution;

[0012] (4) adding any one or a combination of at least two of nickel salt, cobalt salt or manganese salt to the defluorinated liquid in step (3), and finally performing spray pyrolysis to obtain a nickel-cobalt-manganese ternary precursor.

[0013] The present invention first washes the cobalt intermediate to remove SO4 entrained in the raw material. 2-ions, and then hydrochloric acid / nitric acid reduction leaching is used, and then iron and aluminum, calcium and magnesium, copper and zinc and fluorine are removed in sequence, and nickel, cobalt and manganese in the cobalt intermediate are not extracted. After impurities are removed, any one or a combination of at least two of nickel salts, cobalt salts or manganese salts are added as needed, and finally spray pyrolysis is used to directly prepare a nickel-cobalt-manganese ternary precursor. Therefore, the present invention is not for directly obtaining a sulfate solution or a ternary sulfate solution, so in step (1), washing is performed to remove sulfate, and the acid used for reduction leaching is nitric acid and / or hydrochloric acid, and nickel, cobalt and manganese in the cobalt intermediate are not extracted. Compared with the full extraction process, the present invention does not generate a large amount of extraction wastewater, nor does it generate a large amount of sodium sulfate salt, which not only reduces the generation of waste materials and greatly reduces costs, but also can directly prepare a nickel-cobalt-manganese ternary precursor.

[0014] Since the present invention uses nitric acid and / or hydrochloric acid volatile acid for reduction acid leaching, the volatile acid obtained when preparing the nickel-cobalt-manganese ternary precursor by spray pyrolysis can be reused in the reduction leaching stage.

[0015] The cobalt intermediate product mentioned in the present invention refers to a product in the intermediate stage produced during the mining and refining process of cobalt ore. Its main component is cobalt hydroxide, which mainly includes 20% to 40% Co, 0.2 to 2% Ni, 4 to 6% Mn, 5% to 10% Mg, and other small amounts of impurities such as Ca, Cu, Fe and Cr.

[0016] Preferably, the washing temperature in step (1) is 50-80°C, for example, 50°C, 60°C, 70°C or 80°C, the solid-liquid ratio is 1g:(2-4)mL, for example, 1g:2mL, 1g:3mL or 1g:4mL, and the washing time is 1-4h, for example, 1h, 2h, 3h or 4h, but is not limited to the listed values, and other values not listed within the numerical range are also applicable.

[0017] Preferably, the washing liquid used in step (1) comprises an alkaline solution.

[0018] Preferably, the concentration of the alkaline solution is 0 to 5 wt %, but does not include 0 wt %. For example, it can be 0.1 wt %, 1 wt %, 2 wt %, 3 wt %, 4 wt % or 5 wt %, but is not limited to the listed values. Other values not listed within the numerical range are also applicable.

[0019] Preferably, the alkaline solution comprises sodium hydroxide solution.

[0020] Preferably, the reducing agent used in the reduction leaching in step (2) includes hydrogen peroxide or SO2.

[0021] Preferably, the amount of the reducing agent is 4 to 10 times the molar amount of the cobalt element in the cobalt intermediate, for example, it can be 4 times, 5 times, 6 times, 7 times, 8 times, 9 times or 10 times, but is not limited to the listed values, and other values not listed within the numerical range are also applicable.

[0022] Preferably, the temperature of the reduction leaching in step (2) is 50-80°C, for example, 50°C, 60°C, 70°C or 80°C, the solid-liquid ratio is 1g:(2-4)mL, for example, 1g:2mL, 1g:3mL or 1g:4mL, the time is 1-4h, for example, 1h, 2h, 3h or 4h, and the endpoint pH is 1-2, for example, 1, 1.2, 1.4, 1.6, 1.8 or 2, but is not limited to the listed values, and other values not listed within the numerical range are also applicable.

[0023] Preferably, the oxidant used for removing iron and aluminum in step (3) includes sodium chlorate.

[0024] Preferably, the amount of the oxidant is 0.4 to 0.8 times the mass of the iron element in the cobalt intermediate, for example, it can be 0.4 times, 0.5 times, 0.6 times, 0.7 times or 0.8 times, but is not limited to the listed values. Other values not listed within the numerical range are also applicable.

[0025] Preferably, the precipitant for removing iron and aluminum in step (3) comprises the cobalt intermediate after washing in step (1).

[0026] The present invention uses the washed cobalt intermediate as a precipitant for removing iron and aluminum. Conventional liquid caustic soda or calcium hydroxide is used for neutralization of iron and aluminum. Since the cobalt intermediate is a metal hydroxide, its alkalinity can be used to neutralize the residual acid in the leachate, achieving the purpose of removing iron and aluminum and reducing costs. Furthermore, the use of liquid caustic soda or calcium hydroxide introduces sodium or calcium into the leachate, increasing the difficulty of back-end impurity removal.

[0027] Preferably, the endpoint pH of the iron and aluminum removal in step (3) is 4 to 5.5, for example, 4, 4.5, 5.0 or 5.5, and the temperature is 60 to 80°C, for example, 60°C, 65°C, 70°C, 75°C or 80°C, but is not limited to the listed values, and other unlisted values within the numerical range are also applicable.

[0028] Preferably, the method for removing calcium and magnesium in step (3) comprises adding fluoride to the liquid after iron and aluminum removal to carry out a reaction.

[0029] Preferably, calcium and magnesium are removed according to a molar ratio of calcium + magnesium elements to fluoride in the cobalt intermediate of 1: (1 to 1.5), for example, it can be 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4 or 1:1.5, but is not limited to the listed values, and other values not listed within the numerical range are also applicable.

[0030] Preferably, the time for removing calcium and magnesium in step (3) is 1 to 4 hours, for example, 1 hour, 2 hours, 3 hours or 4 hours, and the temperature is 60 to 80°C, for example, 60°C, 65°C, 70°C, 75°C or 80°C, but is not limited to the listed values, and other values not listed within the numerical range are also applicable.

[0031] Preferably, the method for removing copper and zinc in step (3) comprises extracting and removing copper and zinc using P204 to obtain a liquid after removing copper and zinc.

[0032] Preferably, the ratio of the extraction with P204 is (1 / 3 to 3):1, for example, it can be 1 / 3:1, 1:1, 1.5:1, 2:1, 2.5:1 or 3:1, but is not limited to the listed values, and other unlisted values within the numerical range are also applicable.

[0033] Preferably, the fluorine removal method in step (3) comprises adjusting the pH of the copper-zinc-removed liquid obtained by removing copper and zinc, extracting with an ester extractant, stripping with a sodium hydroxide solution, and finally further removing fluorine with an adsorption material.

[0034] In addition to extracting and removing fluorine, the present invention also uses adsorption materials to carry out deep fluorine removal.

[0035] Preferably, the pH of the solution after copper and zinc removal is adjusted to 1-2, for example, 1, 1.2, 1.4, 1.6, 1.8 or 2, but is not limited to the listed values, and other values not listed within the numerical range are also applicable.

[0036] Preferably, the ratio of extraction using an ester extractant is (1 / 3 to 3):1, for example, it can be 1 / 3:1, 1:1, 1.5:1, 2:1, 2.5:1 or 3:1, but is not limited to the listed values, and other unlisted values within the numerical range are also applicable.

[0037] Preferably, when the fluorine concentration in the stripping liquid obtained by the stripping reaches 30 to 40 g / L, for example, 30 g / L, 35 g / L or 40 g / L, the stripping liquid is returned to the calcium and magnesium removal step for calcium and magnesium removal.

[0038] Since the present invention uses fluoride to remove calcium and magnesium, the stripping solution obtained by defluorination can be enriched with fluorine. When the fluorine reaches a certain concentration, the fluoride obtained by defluorination and enrichment can be returned to the calcium and magnesium removal step to achieve the recycling and reuse of fluoride.

[0039] Preferably, the adsorption material includes an aluminum-based adsorption material and / or a zirconium-based adsorption material.

[0040] Preferably, the fluorine concentration in the defluorinated liquid obtained by defluorination in step (3) is lower than 5 mg / L, for example, it can be 5 mg / L, 4 mg / L, 3 mg / L, 4 mg / L or 1 mg / L, but is not limited to the listed values. Other values not listed within the numerical range are also applicable.

[0041] Preferably, according to the type of the required nickel-cobalt-manganese ternary precursor, any one or a combination of at least two of the corresponding nickel salt, cobalt salt or manganese salt is added to the defluorinated liquid, and finally spray pyrolysis is performed.

[0042] Preferably, the temperature of the spray pyrolysis in step (4) is 600-900°C, for example, 600°C, 700°C, 800°C or 900°C, and the time is 1-15s, for example, 1s, 5s, 10s or 15s, but is not limited to the listed values, and other values not listed within the numerical range are also applicable.

[0043] Preferably, the acid obtained from the spray pyrolysis in step (4) is recycled to the reduction leaching step.

[0044] Compared with the prior art, the present invention has the following beneficial effects:

[0045] The present invention is not intended to directly obtain a metal sulfate solution or a ternary sulfate solution, but to avoid extracting nickel, cobalt, and manganese, thereby reducing costs. Therefore, in step (1), the present invention performs washing to remove sulfate ions, and the acid used for reduction leaching is nitric acid and / or hydrochloric acid, so that nickel, cobalt, and manganese in the cobalt intermediate are not extracted. Compared with the full extraction process, the present invention does not generate a large amount of extraction wastewater or a large amount of sodium sulfate salt, which not only reduces the generation of waste materials and greatly reduces costs, but also can directly prepare a nickel, cobalt, and manganese ternary precursor. Therefore, the method of the present invention is different from the conventional full extraction process in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 This is a flow chart of the method described in Example 1 of the present invention. DETAILED DESCRIPTION

[0047] The technical solution of the present invention is further described below by way of specific embodiments. It should be understood by those skilled in the art that the embodiments are merely to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0048] The composition table of the cobalt intermediates used in the following examples and comparative examples is as follows:

[0049]

[0050] Example 1

[0051] This embodiment provides a method for recycling and processing cobalt intermediates. The flow chart of the method is as follows: Figure 1 As shown, the method specifically includes the following steps:

[0052] (1) washing the cobalt intermediate with a 1 wt % sodium hydroxide solution at a temperature of 60° C., a solid-liquid ratio of 1 g:3 mL, and a washing time of 2 h to obtain a washed cobalt intermediate;

[0053] (2) subjecting the washed cobalt intermediate product of step (1) to reduction leaching using hydrochloric acid and hydrogen peroxide to obtain a leachate; wherein the amount of hydrogen peroxide used is 5 times the molar amount of cobalt element in the cobalt intermediate product, the reduction leaching temperature is 60° C., the solid-liquid ratio is 1 g:3 mL, the time is 2 h, and the endpoint pH is 1.5;

[0054] (3) adding sodium chlorate and the washed cobalt intermediate product of step (1) to the leachate of step (2) to remove iron and aluminum to obtain a solution after iron and aluminum removal, wherein the endpoint pH of the iron and aluminum removal is 5, the temperature is 60° C., and the amount of sodium chlorate used is 0.5 times the mass of the iron element in the cobalt intermediate product;

[0055] (4) adding sodium fluoride to the iron and aluminum-removed solution in step (3) to remove calcium and magnesium to obtain a calcium and magnesium-removed solution, wherein the molar ratio of calcium + magnesium elements to sodium fluoride in the cobalt intermediate product is 1:1.2 for removing calcium and magnesium, and the time for removing calcium and magnesium is 2 hours and the temperature is 60°C;

[0056] (5) extracting the calcium and magnesium-removed solution in step (4) with P204 at a ratio of 1:1 to obtain a copper and zinc-removed solution;

[0057] (6) After the copper and zinc are removed, the pH of the liquid is adjusted to 1.2, and an ester extractant TBP is used to perform an extraction reaction at a ratio of 1:1. Then, a sodium hydroxide solution is used to strip the loaded organic phase. The fluorine concentration of the stripping liquid is enriched to 38.3 g / L and returned to the calcium and magnesium removal process of step (4). Then, an aluminum-based adsorption material (Al2O3) is used for deep fluorine removal to obtain a fluorine concentration of 3.6 mg / L in the defluorinated liquid.

[0058] (7) According to the nickel-cobalt-manganese ternary precursor type of NCM811, nickel chloride, manganese chloride and cobalt chloride are added to the defluorinated liquid in step (6), and finally spray pyrolysis is carried out at 65°C for 8s to obtain a nickel-cobalt-manganese ternary precursor. The acid obtained by the spray pyrolysis is reused in the reduction leaching step in step (2).

[0059] Example 2

[0060] This embodiment provides a method for recycling and processing cobalt intermediates, the method specifically comprising the following steps:

[0061] (1) washing the cobalt intermediate with a 3 wt % sodium hydroxide solution at a temperature of 80° C., a solid-liquid ratio of 1 g:2 mL, and a washing time of 1 h to obtain a washed cobalt intermediate;

[0062] (2) subjecting the washed cobalt intermediate product of step (1) to reduction leaching using hydrochloric acid and hydrogen peroxide to obtain a leachate; wherein the amount of hydrogen peroxide used is 10 times the molar amount of cobalt element in the cobalt intermediate product, the reduction leaching temperature is 50° C., the solid-liquid ratio is 1 g:2 mL, the time is 1 h, and the endpoint pH is 2;

[0063] (3) adding sodium chlorate and the washed cobalt intermediate product of step (1) to the leachate of step (2) to remove iron and aluminum to obtain a solution after iron and aluminum removal, wherein the end point pH of the iron and aluminum removal is 4, the temperature is 70° C., and the amount of sodium chlorate used is 0.6 times the mass of the iron element in the cobalt intermediate product;

[0064] (4) adding sodium fluoride to the iron and aluminum-removed solution in step (3) to remove calcium and magnesium to obtain a calcium and magnesium-removed solution, wherein the molar ratio of calcium + magnesium elements to sodium fluoride in the cobalt intermediate product is 1:1 for removing calcium and magnesium, and the time for removing calcium and magnesium is 4 hours and the temperature is 80°C;

[0065] (5) extracting the calcium and magnesium-removed solution in step (4) with P204 at a ratio of 3:1 to obtain a copper and zinc-removed solution;

[0066] (6) After the copper and zinc are removed, the pH of the liquid is adjusted to 1, and an ester extractant TBP is used to perform an extraction reaction at a ratio of 3:1. Then, a sodium hydroxide solution is used to strip the loaded organic phase. The fluorine concentration of the stripping liquid is enriched to 40 g / L and returned to the calcium and magnesium removal process in step (4). Then, an aluminum-based or zirconium-based adsorption material is used for deep fluorine removal to obtain a fluorine concentration of 3 mg / L in the defluorinated liquid.

[0067] (7) According to the nickel-cobalt-manganese ternary precursor type of NCM811, nickel chloride, manganese chloride and cobalt chloride are added to the defluorinated liquid in step (6), and finally spray pyrolysis is carried out at 900°C for 3s to obtain a nickel-cobalt-manganese ternary precursor. The acid obtained by the spray pyrolysis is reused in the reduction leaching step in step (2).

[0068] Example 3

[0069] This embodiment provides a method for recycling and processing cobalt intermediates, the method specifically comprising the following steps:

[0070] (1) washing the cobalt intermediate with a 5 wt % sodium hydroxide solution at a temperature of 50° C., a solid-liquid ratio of 1 g:4 mL, and a washing time of 4 h to obtain a washed cobalt intermediate;

[0071] (2) subjecting the washed cobalt intermediate product of step (1) to reduction leaching using nitric acid and hydrogen peroxide to obtain a leachate; wherein the amount of hydrogen peroxide used is 4 times the molar amount of cobalt element in the cobalt intermediate product, the reduction leaching temperature is 80° C., the solid-liquid ratio is 1 g:4 mL, the time is 4 h, and the endpoint pH is 1;

[0072] (3) adding sodium chlorate and the washed cobalt intermediate product of step (1) to the leachate of step (2) to remove iron and aluminum to obtain a solution after removing iron and aluminum, wherein the endpoint pH of the de-ironization and aluminum removal is 5.5, the temperature is 80° C., and the amount of sodium chlorate used is 0.8 times the mass of the iron element in the cobalt intermediate product;

[0073] (4) adding sodium fluoride to the iron and aluminum-removed solution in step (3) to remove calcium and magnesium to obtain a calcium and magnesium-removed solution, wherein the molar ratio of calcium + magnesium elements to sodium fluoride in the cobalt intermediate product is 1:1.5 for removing calcium and magnesium, and the time for removing calcium and magnesium is 1 hour and the temperature is 60°C;

[0074] (5) extracting the calcium and magnesium-removed solution in step (4) with P204 at a ratio of 1:1 to obtain a copper and zinc-removed solution;

[0075] (6) After the copper and zinc are removed, the pH of the liquid is adjusted to 2, and an ester extractant TBP is used to perform an extraction reaction in a ratio of 1:1. Then, a sodium hydroxide solution is used to strip the loaded organic phase. The fluorine concentration of the stripping liquid is enriched to 30 g / L and returned to the calcium and magnesium removal process in step (4). Then, an aluminum-based or zirconium-based adsorption material is used for deep fluorine removal to obtain a fluorine concentration of 4.5 mg / L after defluorination.

[0076] (7) According to the nickel-cobalt-manganese ternary precursor type of NCM811, nickel chloride, manganese chloride and cobalt chloride are added to the defluorinated liquid in step (6), and finally spray pyrolysis is carried out at 600°C for 15s to obtain a nickel-cobalt-manganese ternary precursor. The acid obtained by the spray pyrolysis is reused in the reduction leaching step in step (2).

[0077] Example 4

[0078] This embodiment provides a method for recycling and treating a cobalt intermediate. The method is the same as that of Example 1 except that the washed cobalt intermediate to which iron and aluminum are added in step (3) is replaced with sodium hydroxide.

[0079] Comparative Example 1

[0080] This comparative example provides a method for recycling and processing cobalt intermediates, the method comprising the following steps:

[0081] (1) Reduction leaching of the cobalt intermediate using hydrochloric acid and hydrogen peroxide to obtain a leachate; wherein the amount of hydrogen peroxide used is 5 times the molar amount of cobalt element in the cobalt intermediate, the reduction leaching temperature is 60° C., the solid-liquid ratio is 1 g:3 mL, the time is 2 h, and the endpoint pH is 1.5;

[0082] (2) adding sodium chlorate and a cobalt intermediate to the leachate of step (1) to remove iron and aluminum to obtain a solution after the removal of iron and aluminum, wherein the endpoint pH of the de-ironization and the temperature are 5 and 60° C., and the amount of sodium chlorate used is 0.5 times the mass of the iron element in the cobalt intermediate;

[0083] (3) extracting and removing impurities from the liquid after the iron and aluminum removal in step (2) using saponified P204, separating cobalt, nickel and magnesium from the raffinate, and purifying the stripping liquid to obtain a battery-grade manganese sulfate solution;

[0084] (4) extracting cobalt and magnesium from the raffinate of step (3) using saponified P507, and purifying the raffinate for nickel to obtain a battery nickel sulfate solution;

[0085] (5) using saponified P507 to extract cobalt from the stripping solution of step (4), wherein the stripping solution is a battery-grade cobalt sulfate solution;

[0086] (6) According to the molar ratio of nickel, cobalt and manganese as the ternary precursor of NCM811, battery-grade nickel sulfate, cobalt sulfate and manganese sulfate solutions are mixed into a ternary solution, and liquid alkali and ammonia water are added as precipitants and complexing agents, and the precursor is obtained by precipitation reaction.

[0087] Comparative Example 2

[0088] This comparative example provides a method for recycling and treating a cobalt intermediate. The method is the same as Example 1 except that step (1) is not performed.

[0089] Comparative Example 3

[0090] This comparative example provides a method for recovering and treating a cobalt intermediate. The method is the same as Example 1 except that the hydrochloric acid in step (2) is replaced by sulfuric acid for reduction acid leaching.

[0091] As can be seen from Examples 1-4 and Comparative Example 1, Comparative Example 1 performs a multi-step extraction, and the nickel, cobalt, and manganese extraction process requires the consumption of liquid alkali or ammonia to saponify the organic phase. Typically, 2 mol of NaOH or ammonia is required to extract 1 mol of metal ions. Since the main elements of the cobalt intermediate are nickel, cobalt, and manganese, the cost of saponification of the metal ions cannot be omitted during the entire extraction process. The method for recovering and treating the cobalt intermediate of the present invention does not extract the main metals nickel, cobalt and manganese, and its processing cost is 2,000 to 3,000 yuan per ton lower than that of the conventional method, and it also saves the process of preparing the ternary liquid from the unit liquid; as can be seen from Example 1 and Comparative Examples 2-3, the overall process of the present invention cooperates with each other, and the cobalt intermediate needs to be washed first, the purpose of which is to elute and remove the sulfate ions in the cobalt intermediate raw material, and at the same time, nitric acid and / or hydrochloric acid is used instead of sulfuric acid for reduction leaching to ensure that the product liquid is a chlorine system or a nitrate system, which can be directly sprayed and pyrolyzed; as can be seen from Examples 1 and 4, the washed cobalt intermediate that can be used for removing iron and aluminum in the present invention can reduce cost consumption and will not introduce impurities such as Na or Ca. If sodium hydroxide is used as a neutralizing agent for neutralization, it will increase the cost, so the use of the cobalt intermediate as a neutralizing agent saves the cost of sodium hydroxide.

[0092] The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for recycling and treating cobalt intermediates, characterized in that: The method comprises the following steps: (1) washing the cobalt intermediate product to obtain a washed cobalt intermediate product; (2) subjecting the washed cobalt intermediate product of step (1) to reduction leaching to obtain a leachate, wherein the acid used in the reduction leaching comprises hydrochloric acid and / or nitric acid; (3) removing iron and aluminum, calcium and magnesium, copper and zinc, and fluorine from the leachate in step (2) to obtain a defluorinated solution; (4) adding any one or a combination of at least two of nickel salt, cobalt salt or manganese salt to the defluorinated liquid in step (3), and finally performing spray pyrolysis to obtain a nickel-cobalt-manganese ternary precursor.

2. The method according to claim 1, characterized in that The washing temperature in step (1) is 50-80° C., the solid-liquid ratio is 1 g: (2-4) mL, and the washing time is 1-4 h; Preferably, the washing liquid used in step (1) comprises an alkaline solution; Preferably, the concentration of the alkaline solution is 0 to 5 wt %, but excluding 0 wt %; Preferably, the alkaline solution comprises sodium hydroxide solution.

3. The method according to claim 1 or 2, characterized in that The reducing agent used in the reduction leaching in step (2) includes hydrogen peroxide or SO2; Preferably, the amount of the reducing agent is 4 to 10 times the molar amount of the cobalt element in the cobalt intermediate; Preferably, the reduction leaching temperature in step (2) is 50-80° C., the solid-liquid ratio is 1 g:(2-4) mL, the time is 1-4 h, and the endpoint pH is 1-2.

4. The method according to any one of claims 1 to 3, characterized in that The oxidant used in the iron and aluminum removal in step (3) includes sodium chlorate; Preferably, the amount of the oxidant is 0.4 to 0.8 times the mass of the iron element in the cobalt intermediate; Preferably, the precipitant for removing iron and aluminum in step (3) comprises the cobalt intermediate product after washing in step (1); Preferably, the end point pH of the iron and aluminum removal in step (3) is 4 to 5.5, and the temperature is 60 to 80°C.

5. The method according to any one of claims 1 to 4, characterized in that The method for removing calcium and magnesium in step (3) comprises adding fluoride to the liquid after iron and aluminum removal to react; Preferably, calcium and magnesium are removed in a molar ratio of calcium + magnesium elements to fluoride in the cobalt intermediate product of 1: (1 to 1.5); Preferably, the time for removing calcium and magnesium in step (3) is 1 to 4 hours, and the temperature is 60 to 80°C.

6. The method according to any one of claims 1 to 5, characterized in that The method for removing copper and zinc in step (3) comprises extracting and removing copper and zinc using P204 to obtain a copper and zinc-removed liquid; Preferably, the extraction ratio using P204 is (1 / 3 to 3):

1.

7. The method according to any one of claims 1 to 6, characterized in that The defluorination method in step (3) comprises adjusting the pH of the copper-zinc-removed solution obtained by removing copper and zinc, extracting it with an ester extractant, stripping it with a sodium hydroxide solution, and finally further removing the fluorine with an adsorption material.

8. The method according to claim 7, characterized in that After removing copper and zinc, the liquid is adjusted to a pH of 1 to 2; Preferably, the ratio of the extraction using the ester extractant is (1 / 3 to 3):1; Preferably, when the fluorine concentration in the stripping solution obtained by the stripping reaches 30-40 g / L, the stripping solution is returned to the calcium and magnesium removal step for calcium and magnesium removal; Preferably, the adsorption material comprises an aluminum-based adsorption material and / or a zirconium-based adsorption material; Preferably, the fluorine concentration in the defluorinated liquid obtained by defluorination in step (3) is lower than 5 mg / L.

9. The method according to any one of claims 1 to 8, characterized in that According to the type of the required nickel-cobalt-manganese ternary precursor, any one or a combination of at least two of the corresponding nickel salt, cobalt salt or manganese salt is added to the defluorinated liquid, and finally spray pyrolysis is performed.

10. The method according to any one of claims 1 to 9, characterized in that The temperature of the spray pyrolysis in step (4) is 600-900° C. and the time is 1-15 seconds; Preferably, the acid obtained from the spray pyrolysis in step (4) is recycled to the reduction leaching step.

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