A method for preparing a precursor sulfate solution using a nickel cobalt hydroxide intermediate and its application

Abstract

This invention relates to the field of cathode precursor technology, specifically to a method for preparing a sulfate solution for a precursor using a nickel-cobalt hydroxide intermediate and its application. The intermediate is acid-leached and then a flocculant is added to obtain a cobalt-nickel-manganese mixed solution and manganese slag. The cobalt-nickel-manganese mixed solution is extracted with P507-C272, and then back-extracted with a supported organic material to obtain a crude manganese sulfate solution. The raffinate is purified by P204, and cobalt is recovered using P507 to obtain a cobalt sulfate solution, which is then separated into nickel and magnesium by C272 to obtain a nickel sulfate solution. The manganese slag is reduced and leached to obtain a reduced leachate, which is then mixed with a sodium carbonate solution to remove iron, resulting in an iron-removed solution. The iron-removed solution is mixed with the crude manganese sulfate solution to remove calcium and magnesium, resulting in a calcium- and magnesium-removed solution. The calcium- and magnesium-removed solution is mixed with an aluminum source to remove fluorine, resulting in a fluorine-removed solution. The fluorine-removed solution is mixed with sulfides to remove copper and zinc, and then an alkaline solution is added to obtain a heavy-duty solution. This solution is treated with a modified resin to obtain a refined manganese sulfate solution. This method has a high manganese recovery rate and low processing cost.

Description

Technical Field

[0001] This invention relates to the field of cathode precursor technology, and more specifically, to a method for preparing a sulfate solution for a precursor using nickel-cobalt hydroxide intermediate and its application. Background Technology

[0002] Nickel-cobalt hydroxide intermediate (MHP) is a mixed hydroxide containing nickel (Ni) and cobalt (Co). It is an important intermediate raw material with wide applications in battery manufacturing and the synthesis of other nickel-cobalt materials. MHP is typically prepared from laterite nickel ore using high-pressure acid leaching (HPAL) technology. Due to limitations in its production process, MHP contains a significant amount of impurities, such as manganese, iron, copper, and cobalt.

[0003] In existing technologies, manganese recovery using MHP as a raw material suffers from low recovery rates and high processing costs. This is because manganese in MHP primarily exists as oxides, and their small particle size leads to slow slag filtration. Therefore, the nickel-cobalt hydroxide leaching process often employs a complete reduction process, requiring all manganese ions to be separated via a P204 extraction line. However, due to the presence of Ca ions in the solution, hydrochloric acid back-extraction is mainly used to prevent calcium sulfate precipitation during extraction. This necessitates an additional extraction line for manganese sulfate conversion, increasing extraction costs and resulting in poor economic efficiency. Furthermore, some processes utilize a precipitation-dissolution-concentration crystallization process to recover manganese. This process requires controlling the crystallization rate (typically 50%–60%) during concentration, leading to low direct Mn recovery and a large amount of metal circulating within the crystallization system, further increasing costs.

[0004] In view of this, the present invention is hereby proposed. Summary of the Invention

[0005] The primary objective of this invention is to provide a method for preparing a precursor sulfate solution using nickel-cobalt hydroxide intermediates. This method offers high manganese recovery and low processing costs. Specifically, the mixed solution of nickel, cobalt, and manganese sulfate obtained after acid leaching is subjected to a P507-C272 composite extractant, which separates most of the manganese ions. The use of P507 extractant increases the extraction loading, while Ca ions remain in the raffinate, achieving the goal of using sulfuric acid for back-extraction without producing calcium sulfate slag. Furthermore, the synergistic extraction with P507-C272 increases the total extractant concentration. Appropriate enhancement of extractant performance using P507 lowers the reaction temperature, accelerates phase separation, and improves the saponification rate and extractant utilization. This increases the processing capacity (volume) of the extraction line and reduces production costs without affecting the overall extraction process.

[0006] A second objective of this invention is to provide an application of a method for preparing a sulfate solution for a precursor using a nickel-cobalt hydroxide intermediate.

[0007] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted:

[0008] This invention provides a method for preparing a sulfate solution for a precursor using a nickel-cobalt hydroxide intermediate, comprising the following steps:

[0009] (a) The intermediate nickel-cobalt hydroxide was mixed with sulfuric acid solution and acid leached. Then, a flocculant was added to it for sedimentation, followed by solid-liquid separation to obtain a mixed solution of cobalt-nickel-manganese sulfate and manganese slag.

[0010] (b) Adjust the pH of the cobalt-nickel-manganese sulfate mixed solution to ≥5.5, and then perform solid-liquid separation to obtain the post-precipitation liquid and the precipitate residue;

[0011] (c) After adjusting the pH of the precipitated liquid to 2.0–3.5, it is mixed with a composite extractant containing P507 and C272 and subjected to a first extraction to obtain a raffinate and a loaded organic phase; the loaded organic phase is back-extracted to obtain a crude manganese sulfate solution; the raffinate is mixed with P204 extractant for impurity removal to obtain a purified liquid; the purified liquid is subjected to a second extraction using P507 extractant to obtain a refined cobalt sulfate solution and a nickel-magnesium raffinate; the nickel-magnesium raffinate is subjected to a third extraction using C272 extractant to obtain a refined nickel sulfate solution;

[0012] (d) The manganese slag is mixed with sulfuric acid solution and reducing agent and subjected to reduction leaching to obtain reduction leaching solution; the reduction leaching solution is mixed with sodium carbonate solution and subjected to iron removal reaction, followed by solid-liquid separation to obtain yellow sodium iron alum slag and iron-removed liquid;

[0013] (e) After mixing the iron-removed liquid with the crude manganese sulfate solution, manganese fluoride is added to remove calcium and magnesium; then solid-liquid separation is performed to obtain fluoride-removed slag and calcium and magnesium-removed liquid.

[0014] (f) The calcium and magnesium removed liquid is mixed with an aluminum source and subjected to defluorination treatment, and then solid-liquid separation is performed to obtain defluorinated liquid and crude aluminum fluoride.

[0015] (g) The defluorinated liquid is mixed with sulfide and subjected to copper and zinc removal treatment. After solid-liquid separation, a copper and zinc removed liquid is obtained. An alkaline solution is added to the copper and zinc removed liquid to remove Co, Ni, Al, and Sc. Then, solid-liquid separation is performed to obtain a heavy removal liquid.

[0016] (h) After adjusting the pH of the deweighted liquid to acidic, Si, F and P are removed by using a modified resin to obtain a refined manganese sulfate solution.

[0017] Further, in step (a), the step of mixing the nickel-cobalt hydroxide intermediate with sulfuric acid solution and acid leaching specifically includes: first mixing the nickel-cobalt hydroxide intermediate with the water to form a slurry, and then adding concentrated sulfuric acid solution to it; preferably, the liquid-solid ratio of the nickel-cobalt hydroxide intermediate to the water is 1.8 to 2.5 g / ml; preferably, the pH of the acid leaching reaction system and / or the pH of the final pH of the acid leaching reaction is 0.5 to 1.0.

[0018] Furthermore, in step (a), the acid leaching temperature is 80–90°C.

[0019] Furthermore, in step (a), the acid leaching time is 3 to 6 hours.

[0020] Furthermore, in step (a), the mass concentration of nickel in the leachate obtained after acid leaching is ≤100g / L.

[0021] Further, in step (a), the flocculant includes at least one of alkyl quaternary ammonium salt cationic surfactant solution, ester quaternary ammonium salt cationic surfactant solution, and polymeric cationic surfactant solution; preferably, the polymeric cationic surfactant solution includes cationic polyacrylamide solution; preferably, the mass fraction of the polymeric cationic surfactant solution is 0.5‰ to 1.5‰; preferably, the amount of polymeric cationic surfactant solution added is 5 to 10 mg / L.

[0022] Further, in step (a), after adding the flocculant, stir for 10 to 30 minutes, and then let it stand for 30 to 60 minutes to allow the sedimentation to proceed.

[0023] Further, in step (b), the adjustment is carried out using a slurry or alkaline solution containing nickel-cobalt hydroxide intermediate;

[0024] Further, in step (b), after obtaining the precipitate, the precipitate is mixed with a dilute sulfuric acid solution or a concentrated sulfuric acid solution and leached to obtain a leachate. Then, the leachate is mixed with the nickel-cobalt hydroxide intermediate to obtain a slurry of the nickel-cobalt hydroxide intermediate.

[0025] Further, in step (c), the pH of the precipitate is adjusted using concentrated sulfuric acid solution or dilute sulfuric acid solution.

[0026] Further, in step (c), the composite extractant containing P507 and C272 comprises P507 extractant, C272 extractant and solvent in a mass ratio of 10-15:10-15:70-80, wherein the solvent is sulfonated kerosene.

[0027] Furthermore, in step (c), the saponification rate of the first extract is 50% to 55%.

[0028] Further, in step (c), the ratio of O / A in the first extraction is 1.5 to 2:1.

[0029] Further, in step (c), the supported organic phase is back-extracted using a dilute sulfuric acid solution, wherein the molar concentration of the dilute sulfuric acid solution is 2.2–2.5 mol / L.

[0030] Further, in step (d), the sulfuric acid solution includes a dilute sulfuric acid solution or a concentrated sulfuric acid solution.

[0031] Further, in step (d), the reducing agent includes hydrogen peroxide solution; preferably, the hydrogen peroxide solution is added over a period of 3 to 4 hours; preferably, the reaction is continued at a constant temperature for 1 hour after the hydrogen peroxide solution is added.

[0032] Furthermore, in step (d), the temperature of the reduction leaching is 70–90°C.

[0033] Furthermore, in step (d), the temperature of the iron removal reaction is >90°C.

[0034] Further, in step (d), the reducing leachate and the sodium carbonate solution are added simultaneously, and the addition time is controlled to be 3-4 hours; after the addition is completed, the temperature is maintained for another 2-5 hours to carry out the iron removal reaction.

[0035] Further, in step (d), the pH at the endpoint of the iron removal reaction is 4.0 to 5.0.

[0036] Further, in step (e), the amount of manganese fluoride added is 80 to 120 times the theoretical total mass of the reaction with calcium and magnesium ions.

[0037] Further, in step (e), the pH of the reaction endpoint of the calcium and magnesium removal treatment is 5.0 to 6.0.

[0038] Furthermore, in step (e), the temperature for the calcium and magnesium removal treatment is 80–95°C.

[0039] Furthermore, in step (e), the calcium and magnesium removal treatment time is 6 to 8 hours.

[0040] Further, in step (f), the aluminum source includes at least one of anhydrous aluminum sulfate, aluminum sulfate octadechydrate, and polyaluminum sulfate.

[0041] Further, in step (f), the aluminum source is added according to a molar ratio of F to Al of 3.5 to 5.0:1.

[0042] Furthermore, in step (f), the temperature of the defluorination treatment is 75–90°C.

[0043] Furthermore, in step (f), the defluorination treatment takes 4 to 6 hours.

[0044] Further, in step (g), the sulfide includes at least one of manganese sulfide, sodium sulfide, hydrogen sulfide, ammonium sulfide, and ammonium hydrosulfide.

[0045] Further, in step (g), the amount of sulfide added is 10 to 15 times the theoretical total mass of the reaction with copper and zinc ions.

[0046] Furthermore, in step (g), the copper and zinc removal treatment time is 1 to 2 hours.

[0047] Further, in step (g), the alkaline solution includes at least one of sodium hydroxide solution, potassium hydroxide solution, and ammonia solution.

[0048] Further, in step (g), the amount of alkali solution added is such that the pH of the mixed system is 7.5 to 9.0.

[0049] Further, in step (g), the reaction time for the treatment of Co, Ni, Al, and Sc is 2 to 4 hours.

[0050] Further, in step (h), a dilute sulfuric acid solution or a concentrated sulfuric acid solution is added to adjust the pH of the deweighted solution.

[0051] Further, in step (h), the pH of the deweighted solution is adjusted to 5.5–6.5.

[0052] Furthermore, in step (h), the flow rate for impurity removal using the modified resin is 1–3 BV / h.

[0053] The present invention further provides the application of the refined cobalt sulfate solution, refined nickel sulfate solution and refined manganese sulfate solution obtained by the method of preparing precursor sulfate solution using nickel-cobalt hydroxide intermediate in the preparation of positive electrode precursor, positive electrode material, positive electrode sheet and secondary battery.

[0054] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0055] (1) The method for preparing precursor sulfate solution using nickel-cobalt hydroxide intermediate provided by the present invention effectively improves the manganese recovery rate and has low processing cost.

[0056] (2) The method for preparing precursor sulfate solution using nickel-cobalt hydroxide intermediate provided by the present invention adds a flocculant during the acid leaching process of nickel-cobalt hydroxide intermediate, which can promote the flocculation and agglomeration of manganese dioxide in the intermediate. The separation of nickel-cobalt and manganese dioxide (manganese slag) is achieved through the leaching acid dissolution-flocculation sedimentation process.

[0057] (3) The method for preparing precursor sulfate solution using nickel-cobalt hydroxide intermediate provided by the present invention is that the mixed solution of nickel sulfate, cobalt and manganese obtained by acid dissolution is separated by the action of P507-C272 synergistic extractant. The use of P507 extractant can increase the loading of the extraction process. At the same time, Ca ions remain in the raffinate during the process, which can achieve the purpose of using sulfuric acid back-extraction without producing calcium sulfate slag.

[0058] (4) The method for preparing precursor sulfate solution using nickel-cobalt hydroxide intermediate provided by this invention employs P507-C272 synergistic extraction, which can increase the total concentration of the extractant. P507 is used to appropriately enhance the performance of the extractant, lower the reaction temperature, accelerate the phase separation rate, and improve the extractant utilization rate. Without affecting the overall effect of the extraction process, the processing capacity (throughput) of the extraction line is increased, and production costs are reduced.

[0059] (5) The method for preparing precursor sulfate solution using nickel-cobalt hydroxide intermediate provided by the present invention has low impurity content in the prepared cobalt sulfate solution, nickel sulfate solution and manganese sulfate solution, which meet the requirements for the production and use of ternary precursors.

[0060] (6) The method for preparing precursor sulfate solution using nickel-cobalt hydroxide intermediate provided by the present invention has a fast solid-liquid separation rate and high production efficiency. Attached Figure Description

[0061] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0062] Figure 1 This is a schematic flowchart of the method for preparing a precursor sulfate solution using nickel-cobalt hydroxide intermediates provided by the present invention. Detailed Implementation

[0063] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings and specific embodiments. However, those skilled in the art will understand that the embodiments described below are some embodiments of the present invention, but not all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0064] In a first aspect, this invention provides a method for preparing a precursor sulfate solution using a nickel-cobalt hydroxide intermediate. The method mainly involves leaching and purifying the nickel-cobalt hydroxide intermediate. The precursor sulfate solution includes a cobalt sulfate solution, a nickel sulfate solution, and a manganese sulfate solution. The key focus of this invention is manganese recovery, which improves the manganese recovery rate and reduces costs. See [link to previous section]. Figure 1 As shown, the method specifically includes the following steps:

[0065] (a) The intermediate nickel-cobalt hydroxide is mixed with sulfuric acid solution and acid leached. Then, a flocculant is added to the mixture for sedimentation, followed by solid-liquid separation to obtain a mixed solution of cobalt-nickel-manganese sulfate and manganese slag.

[0066] In some specific implementations, the main components of nickel cobalt hydroxide intermediate (MHP) include nickel cobalt hydroxide (chemical formula NiCo(OH)2) and impurity elements such as manganese, copper, calcium, zinc, magnesium, iron, aluminum, scandium, and silicon.

[0067] In some specific embodiments, the nickel-cobalt hydroxide intermediate contains 30%–50% nickel, 2%–6% cobalt, 3%–10% manganese, 1%–5% magnesium, 0.1%–0.5% copper, 0.1%–0.6% calcium, 0.3%–1.5% zinc, and 0.1%–0.5% silicon.

[0068] In some specific embodiments, before mixing the nickel-cobalt hydroxide intermediate with the sulfuric acid solution, the nickel-cobalt hydroxide intermediate is first mixed with water, and then the sulfuric acid solution is added to carry out an acid leaching reaction.

[0069] The main components of the cobalt-nickel-manganese sulfate mixed solution obtained in step (a) above include sulfate ions, cobalt ions, nickel ions, manganese ions, and impurity ions of magnesium, iron, calcium, and magnesium. The main component of the manganese slag is manganese dioxide.

[0070] (b) Adjust the pH of the cobalt-nickel-manganese sulfate mixed solution to ≥5.5, including but not limited to any one of 5.5, 5.6, 5.8, 6.0, 6.2, 6.3, 6.5 or any range between two of them, preferably 5.5 to 6.5; then perform solid-liquid separation to obtain the precipitated liquid and the precipitated residue.

[0071] (c) After adjusting the pH of the precipitated solution to 2.0–3.5 (including but not limited to any one of 2.0, 2.1, 2.3, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.2, 3.3, 3.5, or a range between any two), it is mixed with a composite extractant containing P507 and C272 and subjected to a first extraction to obtain a raffinate and a loaded organic phase. The purpose of this operation is to extract manganese. The loaded organic phase is back-extracted to obtain a crude manganese sulfate solution. The raffinate is mixed with P204 extractant for impurity removal to obtain a purified solution. The purified solution is subjected to a second extraction using P507 extractant to obtain a refined cobalt sulfate solution and a nickel-magnesium raffinate. The nickel-magnesium raffinate is subjected to a third extraction using C272 extractant to obtain a refined nickel sulfate solution.

[0072] In existing technologies, to ensure good phase separation performance of C272 extractant, the extraction process requires numerous conditions. Generally, rapid phase separation is achieved under relatively high temperatures. Furthermore, due to its high price, its concentration needs to be controlled to minimize loss. Additionally, C272 is difficult to separate phases under high saponification rates, therefore its saponification rate must be controlled to ≤40%, and cannot be too high. These conditions result in low extraction efficiency and high costs.

[0073] This invention employs P507-C272 synergistic extraction, which can increase the total concentration of the extractant. P507 is used to appropriately enhance the performance of the extractant, lower the reaction temperature, accelerate phase separation, and increase the saponification rate to 50%–55%, thereby improving the extractant utilization rate. Without affecting the overall extraction process, the processing capacity (volume) of the extraction line is increased, and production costs are reduced.

[0074] (d) The manganese slag is mixed with sulfuric acid solution and a reducing agent and subjected to reduction leaching to obtain a reduction leachate, the main component of which is manganese sulfate solution. The reduction leachate is mixed with sodium carbonate solution and subjected to an iron removal reaction, followed by solid-liquid separation to obtain sodium ferric sulfate slag and iron-removed liquid. The slag mainly consists of sodium ferric sulfate and a small amount of entrained hydroxides.

[0075] (e) The iron-removed liquid is mixed with the crude manganese sulfate solution, and manganese fluoride is added to perform calcium and magnesium removal treatment. After the calcium and magnesium removal reaction is completed, solid and liquid are separated to obtain defluorination slag and calcium and magnesium-removed liquid. The main components of the defluorination slag include calcium fluoride, magnesium fluoride, and manganese fluoride. Therefore, the defluorination slag can be recycled during the defluorination process until the calcium and magnesium content in the slag reaches a certain level.

[0076] (f) The calcium and magnesium removed liquid is mixed with an aluminum source and subjected to defluorination treatment, followed by solid-liquid separation to obtain the defluorinated liquid and crude aluminum fluoride.

[0077] (g) The defluorinated liquid is mixed with sulfides and subjected to copper and zinc removal treatment. After solid-liquid separation, a copper and zinc removed liquid and copper and zinc sulfide solids are obtained. An alkaline solution is added to the copper and zinc removed liquid to remove Co, Ni, Al, and Sc (causing Co, Ni, Al, and Sc impurities to precipitate). Solid-liquid separation is then performed to obtain a heavy metal removed liquid and filter residue. This filter residue can be sold as a by-product or used to recover valuable metals.

[0078] (h) After adjusting the pH of the deweighted solution to acidic, Si, F and P are removed by using modified resin. After removing the remaining trace amounts of Si, F and P ions in the solution, a refined manganese sulfate solution is obtained.

[0079] In some specific embodiments, in step (h), the refined manganese sulfate solution obtained contains manganese ≥100g / L, cobalt ≤0.005g / L, nickel ≤0.005g / L, copper ≤0.002g / L, iron ≤0.002g / L, zinc ≤0.002g / L, calcium ≤0.005g / L, magnesium ≤0.005g / L, aluminum ≤0.002g / L, and scandium ≤0.003g / L.

[0080] The method for preparing cobalt sulfate solution, nickel sulfate solution and manganese sulfate solution using nickel-cobalt hydroxide intermediate provided by the present invention has high recovery rates for nickel, cobalt and manganese, especially significantly improving the recovery rate of manganese and reducing processing costs.

[0081] Specifically, this invention adds a flocculant during the acid leaching of nickel-cobalt hydroxide intermediates to promote the flocculation and agglomeration of manganese dioxide in the intermediates. This achieves the separation of nickel-cobalt from manganese dioxide (manganese slag) through a leaching acid-dissolution-flocculation sedimentation process. The resulting mixed solution of nickel, cobalt, and manganese sulfate is then processed by a P507-C272 synergistic extractant to separate most of the manganese ions. The use of P507 extractant increases the extraction loading, while Ca ions remain in the raffinate, allowing for sulfuric acid back-extraction without producing calcium sulfate slag. The crude manganese sulfate solution is mixed with the iron-removed solution, and manganese fluoride is used to remove calcium and magnesium, effectively reducing their content. Subsequently, aluminum fluoride is generated by adding an aluminum source to remove fluoride, yielding crude aluminum fluoride as a byproduct. A modified resin is used to adsorb the heavy metals from the solution, removing P, F, and Si ions.

[0082] This invention separates most of the manganese from cobalt and nickel in the initial reaction by using flocculants, centrally treats the manganese slag, and removes impurities from the manganese leaching solution using chemical methods. The operation is simple and easy to control, while improving the direct metal recovery rate and reducing production costs, resulting in a manganese sulfate solution that meets the requirements for precursor production.

[0083] Furthermore, this invention employs P507-C272 synergistic extraction, which can increase the total concentration of the extractant, lower the reaction temperature, accelerate the phase separation rate, and improve the saponification rate of the extraction process to 50%–55%, thereby increasing the utilization rate of the extractant. Without affecting the overall effectiveness of the extraction process, it increases the processing capacity (volume) of the extraction line and reduces production costs.

[0084] The products prepared by this invention mainly include cobalt sulfate solution, nickel sulfate solution, and manganese sulfate solution. Each product has a low impurity content, meeting the requirements for the production and use of ternary precursors. Furthermore, it also produces byproducts such as sodium ferric sulfate slag and crude aluminum fluoride, which can improve economic efficiency.

[0085] Furthermore, in this invention, manganese metal is recovered in a centralized manner, which has a shorter process flow and is simpler to operate compared with the full leaching followed by gradual separation and recovery method.

[0086] In some specific embodiments, step (a), the step of mixing and acid-leaching the nickel-cobalt hydroxide intermediate with sulfuric acid solution, specifically includes: first mixing the nickel-cobalt hydroxide intermediate with water to form a slurry, and then adding concentrated sulfuric acid solution to it. This facilitates subsequent solid-liquid separation.

[0087] Preferably, the liquid-to-solid ratio of the nickel-cobalt hydroxide intermediate to the water is 1.8–2.5 g / ml, including but not limited to any one of 1.8 g / ml, 1.9 g / ml, 2.0 g / ml, 2.1 g / ml, 2.2 g / ml, 2.3 g / ml, 2.4 g / ml, and 2.5 g / ml, or a range between any two. By controlling the liquid-to-solid ratio of the nickel-cobalt hydroxide intermediate to the water, the rate of subsequent solid-liquid separation can be controlled. Using this solid-liquid ratio is beneficial for improving the rate of solid-liquid separation.

[0088] Preferably, the pH of the acid leaching reaction system is 0.5–1.0, including but not limited to a value of any one of 0.5, 0.6, 0.7, 0.8, 0.9, or 1.0, or a range between any two. And / or, the pH at the endpoint of the acid leaching reaction is 0.5–1.0, including but not limited to a value of any one of 0.5, 0.6, 0.7, 0.8, 0.9, or 1.0, or a range between any two.

[0089] In some specific embodiments, in step (a), the acid leaching temperature is 80-90°C; including but not limited to any one of 80°C, 82°C, 83°C, 85°C, 88°C, and 90°C, or any range between two of them.

[0090] In some specific implementations, in step (a), the acid leaching time is 3 to 6 hours; including but not limited to the point value of any one of 3 hours, 4 hours, 5 hours, and 6 hours or the range value between any two.

[0091] In some specific embodiments, in step (a), the mass concentration of nickel in the leachate obtained after acid leaching is ≤100 g / L. The mass concentration of nickel directly affects the separation rate (filtration rate) of solid-liquid separation after sedimentation. Studies have found that when the mass concentration of nickel in the leachate is 80–85 g / L, the filtration rate is 30–35 ml / min; when the mass concentration of nickel in the leachate is 95–100 g / L, the filtration rate is 15–22 ml / min; when the mass concentration of nickel in the leachate is 115–125 g / L, the filtration rate is 4–8 ml / min; and when the mass concentration of nickel in the leachate is 130–135 g / L, the filtration rate is 2–4 ml / min.

[0092] In some specific embodiments, in step (a), the flocculant includes at least one of alkyl quaternary ammonium salt cationic surfactant solution, ester quaternary ammonium salt cationic surfactant solution, and polymeric cationic surfactant solution. Adding a flocculant is beneficial for further improving the rate of subsequent solid-liquid separation. Studies have found that when the mass concentration of nickel in the leachate is 98 g / L, the filtration rate is 2.89 ml / min without flocculant; 7.67 ml / min with 2 mg / L flocculant; 18.00 ml / min with 4 mg / L flocculant; 24.50 ml / min with 6 mg / L flocculant; 18.20 ml / min with 8 mg / L flocculant; and 20.65 ml / min with 10 mg / L flocculant.

[0093] Preferably, the polymeric cationic surfactant solution includes a cationic polyacrylamide solution.

[0094] Preferably, the mass fraction of the polymeric cationic surfactant solution is 0.5‰ to 1.5‰, including but not limited to any one of 0.5‰, 0.6‰, 0.8‰, 1‰, 1.2‰, 1.3‰, and 1.5‰, or any range between two of them.

[0095] Preferably, the amount of the polymeric cationic surfactant solution added is 5 to 10 mg / L, including but not limited to any one of 5 mg / L, 6 mg / L, 7 mg / L, 8 mg / L, 9 mg / L, and 10 mg / L, or any range between two of them; that is, the mass of polymeric cationic surfactant solution added to each 1 L of leachate is 5 to 10 mg.

[0096] In some specific embodiments, in step (a), after adding the flocculant, the mixture is stirred for 10 to 30 minutes (including but not limited to the point value of any one of 10 minutes, 15 minutes, 20 minutes, 25 minutes, and 30 minutes or the range between any two), and then allowed to stand for 30 to 60 minutes (including but not limited to the point value of any one of 30 minutes, 35 minutes, 40 minutes, 45 minutes, 50 minutes, and 60 minutes or the range between any two) to allow the sedimentation to proceed.

[0097] In some specific embodiments, in step (b), the conditioning is performed using a slurry containing a nickel-cobalt hydroxide intermediate.

[0098] It is understood that an alkaline solution such as sodium carbonate solution can also be used for the initial adjustment. In some specific embodiments, in step (b), after obtaining the precipitate, the precipitate is mixed with a dilute sulfuric acid solution or a concentrated sulfuric acid solution and leached to obtain a leachate. Then, the leachate is mixed with the nickel-cobalt hydroxide intermediate to obtain a slurry of the nickel-cobalt hydroxide intermediate. The slurry of the nickel-cobalt hydroxide intermediate obtained here can be used to adjust the pH of the cobalt-nickel-manganese sulfate mixed solution in step (b).

[0099] In some specific embodiments, in step (c), the pH of the precipitated liquid is adjusted using a concentrated sulfuric acid solution or a dilute sulfuric acid solution; a dilute sulfuric acid solution is preferred for easy pH control.

[0100] In some specific embodiments, in step (c), the composite extractant containing P507 and C272 comprises P507 extractant, C272 extractant, and solvent in a mass ratio of 10-15 (including but not limited to point values ​​of any one of 10, 11, 12, 13, 14, 15 or a range between any two): 10-15 (including but not limited to point values ​​of any one of 10, 11, 12, 13, 14, 15 or a range between any two): 70-80 (including but not limited to point values ​​of any one of 70, 72, 75, 78, 80 or a range between any two), wherein the solvent is sulfonated kerosene. Using this composite extractant is beneficial for increasing the total concentration of the extractant, lowering the reaction temperature, accelerating the phase separation rate, increasing the saponification rate, improving the extractant utilization rate, increasing the extraction rate, and reducing production costs.

[0101] In some specific embodiments, in step (c), the saponification rate of the first extract is 50% to 55%, and it is converted to nickel soap. The saponification rate includes, but is not limited to, any one of 50%, 51%, 52%, 53%, 54%, and 55%, or any range between two of them.

[0102] With an overall extractant concentration of approximately 25%, this invention increases the saponification rate from 40% to about 55%, and the extractant utilization rate can be increased to 137.5% of the original. At the same time, based on the price difference between P507 and C272, the cost of extractant can be saved.

[0103] In some specific embodiments, in step (c), the O / A ratio of the first extraction is 1.5 to 2:1, including but not limited to point values ​​or ranges between any one of 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1, and 2:1. This extraction ratio is beneficial for the extraction and separation of Mn. Here, O / A represents the volume ratio of the organic phase to the aqueous phase.

[0104] In some specific embodiments, in step (c), the supported organic phase is back-extracted using a dilute sulfuric acid solution, wherein the molar concentration of the dilute sulfuric acid solution is 2.2 to 2.5 mol / L, including but not limited to any one of 2.2 mol / L, 2.3 mol / L, 2.4 mol / L, and 2.5 mol / L, or a range between any two.

[0105] In some specific embodiments, in step (d), the sulfuric acid solution includes a dilute sulfuric acid solution or a concentrated sulfuric acid solution.

[0106] In some specific embodiments, in step (d), the reducing agent includes a hydrogen peroxide solution.

[0107] Preferably, the hydrogen peroxide solution is added over a period of 3 to 4 hours, for example, 3.5 hours.

[0108] Preferably, after the hydrogen peroxide solution is added, the reaction is continued at a constant temperature for 1 hour.

[0109] In some specific embodiments, the amount of hydrogen peroxide solution added is 8 to 10 mL (e.g., 9 mL) of hydrogen peroxide solution with a mass fraction of 27% to 30% (e.g., 28% or 29%) per 1 g of manganese.

[0110] In some specific implementations, in step (d), the temperature of the reduction leaching is 70 to 90°C, including but not limited to any one of 70°C, 75°C, 80°C, 85°C, and 90°C, or any range between two of them.

[0111] Understandably, the amount of sodium carbonate added can be adjusted based on the pH value at the iron removal endpoint.

[0112] In some specific implementations, in step (d), the amount of sodium carbonate added is: 1.5 to 2 ml of sodium carbonate solution with a mass concentration of 220 to 250 g / L for every 1 g of Mn element.

[0113] In some specific implementations, in step (d), the temperature of the iron removal reaction is >90°C; including but not limited to any one of 92°C, 95°C, 98°C, and 100°C, or any range between two of them.

[0114] In some specific embodiments, in step (d), the reducing leachate and the sodium carbonate solution are added simultaneously, and the addition time is controlled to be 3-4 hours, for example, 3.5 hours. After the addition is completed, the temperature is maintained for another 2-5 hours (including but not limited to any one of 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, 4.5 hours, and 5 hours, or any range between two of them) to carry out the iron removal reaction.

[0115] In some specific embodiments, in step (d), the pH of the reaction endpoint of the iron removal reaction is 4.0 to 5.0, including but not limited to any one of 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.8, 5.0 or any range between two of them; preferably 4.0 to 4.5.

[0116] In some specific embodiments, in step (e), the amount of manganese fluoride added is 80 to 120 times the theoretical total mass of manganese fluoride required to react with calcium and magnesium ions; including but not limited to any one of 80 times, 85 times, 90 times, 95 times, 100 times, 110 times, 120 times or any range between two.

[0117] In some specific embodiments, in step (e), the pH of the reaction endpoint of the calcium and magnesium removal treatment is 5.0 to 6.0, including but not limited to any one of 5.0, 5.2, 5.3, 5.5, 5.8, 6.0 or any range between two of them.

[0118] In some specific embodiments, in step (e), the temperature for calcium and magnesium removal treatment is 80–95°C, including but not limited to any one of 80°C, 83°C, 85°C, 88°C, 90°C, 92°C, and 95°C, or a range between any two. Preferably, it is 85–90°C.

[0119] In some specific implementations, in step (e), the calcium and magnesium removal treatment time is 6 to 8 hours, including but not limited to the point value of any one of 6 hours, 7 hours, and 8 hours or the range value between any two.

[0120] In some specific embodiments, in step (e), the mass concentration of Mg in the solution after calcium and magnesium removal is ≤0.005 g / L and the mass concentration of Ca is ≤0.002 g / L.

[0121] In some specific embodiments, in step (f), the aluminum source includes at least one of anhydrous aluminum sulfate, aluminum sulfate octadechydrate, and polyaluminum sulfate.

[0122] In some specific implementations, in step (f), the aluminum source is added according to a molar ratio of F to Al of 3.5 to 5.0:1 (including but not limited to any one of 3.5:1, 4.0:1, 4.5:1, 5.0:1 or any range between the two).

[0123] In some specific embodiments, in step (f), the temperature of the defluorination treatment is 75-90°C, including but not limited to any one of 75°C, 78°C, 80°C, 82°C, 85°C, 88°C, and 90°C, or any range between two of them; preferably 80-85°C.

[0124] In some specific implementations, in step (f), the defluorination treatment time is 4 to 6 hours, for example, 5 hours.

[0125] In some specific embodiments, in step (f), the mass concentration of F element in the defluorinated liquid is 0.3 to 0.4 g / L.

[0126] In some specific embodiments, in step (g), the sulfide includes at least one of manganese sulfide, sodium sulfide, hydrogen sulfide, ammonium sulfide, and ammonium hydrosulfide.

[0127] In some specific embodiments, in step (g), the amount of sulfide added is 10 to 15 times the theoretical total mass of the reaction with copper and zinc ions, for example, 11 times, 12 times, 13 times or 14 times.

[0128] In some specific implementations, in step (g), the copper and zinc removal treatment takes 1 to 2 hours.

[0129] In some specific embodiments, in step (g), the reaction temperature for the copper and zinc removal treatment is room temperature, for example, 10 to 30°C, but the present invention does not limit this.

[0130] In some specific embodiments, in step (g), the alkaline solution includes at least one of sodium hydroxide solution, potassium hydroxide solution, and ammonia solution.

[0131] In some specific embodiments, in step (g), the amount of alkali solution added is such that the pH of the mixed system is 7.5 to 9.0, including but not limited to any one of 7.5, 7.8, 8, 8.3, 8.5, 8.8, 9.0 or any range between two of them.

[0132] In some specific implementations, in step (g), the reaction time for the treatment of removing Co, Ni, Al, and Sc is 2 to 4 hours, for example, 3 hours.

[0133] In some specific embodiments, in step (h), a dilute sulfuric acid solution or a concentrated sulfuric acid solution is added to adjust the pH of the deweighted solution.

[0134] In some specific embodiments, in step (h), the pH of the deweighted solution is adjusted to 5.5 to 6.5, including but not limited to any one of 5.5, 5.6, 5.8, 6, 6.3, 6.5 or any range between two of them; then the modified resin is used for impurity removal.

[0135] In some specific embodiments, in step (h), the modified resin includes any impurity-removing resin commonly used in the art, such as zirconium ion-modified resin, but is not limited thereto.

[0136] In some specific embodiments, in step (h), the flow rate of the modified resin for impurity removal is 1 to 3 BV / h, including but not limited to any one of 1 BV / h, 1.5 BV / h, 2 BV / h, 2.5 BV / h, 3 BV / h, or any range between two of them.

[0137] In some specific embodiments, the removal of Si, F, and P is carried out in an ion exchange column or a resin exchange column.

[0138] In some specific embodiments, in step (h), the mass concentrations of Si, F, and P in the refined manganese sulfate solution are each ≤0.002 g / L.

[0139] Secondly, the present invention provides the application of the refined cobalt sulfate solution, refined nickel sulfate solution, and refined manganese sulfate solution obtained by the method for preparing precursor sulfate solution using nickel-cobalt hydroxide intermediate in the preparation of positive electrode precursors, positive electrode materials, positive electrode sheets, and secondary batteries.

[0140] It is understandable that the refined cobalt sulfate solution, refined nickel sulfate solution, and refined manganese sulfate solution obtained by the above method can be used to synthesize nickel cobalt manganese precursors or other precursor materials, and then sintered to obtain positive electrode materials, which can then be assembled to produce positive electrode sheets and secondary batteries.

[0141] The refined cobalt sulfate solution, refined nickel sulfate solution, and refined manganese sulfate solution obtained by the above method can be used to prepare positive electrode precursors, positive electrode materials, positive electrode sheets, and secondary batteries at a lower cost.

[0142] The embodiments of the present invention will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer are followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0143] Example 1

[0144] The method for preparing precursor sulfate solutions (cobalt sulfate solution, nickel sulfate solution, and manganese sulfate solution) using nickel-cobalt hydroxide intermediates provided in this embodiment includes the following steps:

[0145] (1) Obtain nickel-cobalt hydroxide intermediate, the chemical composition of which is shown in Table 1 below.

[0146] Table 1 Chemical composition of nickel-cobalt hydroxide intermediate

[0147] <![CDATA[H2O]]> Co Ni Cu Mn Si Sc Fe Ca Mg Zn Al F 52.29％ 1.82％ 20.12％ 0.16％ 2.89％ 0.11％ 0.024％ 0.03％ 0.17％ 1.49％ 0.36％ 0.02％ 0.005％

[0148] According to the liquid-to-solid ratio (L / S) of nickel-cobalt hydroxide intermediate and pure water = 2 g / ml, pure water and nickel-cobalt hydroxide intermediate were mixed and slurried. Then, concentrated sulfuric acid solution was added, and the reaction was maintained at 83℃ for 5 hours. During the reaction, the pH of the system was controlled at 0.8. The pH of the acid leaching reaction endpoint was 0.8. The mass concentration of nickel in the leachate obtained after acid leaching was 80.5 g / L. Cationic polyacrylamide solution (mass fraction 1‰) was added to the leachate at an addition rate of 8 mg / L (i.e., 8 mg of polymeric cationic surfactant solution per L of leachate). After stirring for 20 min, the mixture was allowed to stand for 40 min to settle, and then filtered to obtain a cobalt-nickel-manganese sulfate mixed solution and manganese slag. The contents of cobalt, nickel, copper, manganese, silicon, and scandium in the cobalt-nickel-manganese sulfate mixed solution and manganese slag, as well as the leaching rates of cobalt, nickel, copper, manganese, silicon, and scandium, are shown in Table 2.

[0149] Table 2. Main composition and leaching rate of each element in the cobalt-nickel-manganese sulfate mixed solution and manganese slag.

[0150] element Co Ni Cu Mn Si Sc Nickel-cobalt-manganese mixed solution (g / L) 6.89 83.50 0.65 4.18 0.42 0.10 Manganese slag (wt.%) 1.95 2.35 0.11 55.46 0.11 0.01 Leaching rate (%) 97.90 99.86 97.69 34.75 96.31 98.23

[0151] (2) Using a 13% sodium carbonate solution, the pH of the cobalt-nickel-manganese sulfate mixed solution obtained in step (1) was adjusted to 6, and then filtered to obtain a precipitate and a precipitate residue. The precipitate residue was mixed with a dilute sulfuric acid solution and leached to obtain a leachate. The leachate was then mixed with a nickel-cobalt hydroxide intermediate to obtain a slurry of the nickel-cobalt hydroxide intermediate, which was used for pH adjustment of the cobalt-nickel-manganese sulfate mixed solution in step (2) in other embodiments.

[0152] (3) The precipitate obtained in step (2) was adjusted to pH 2.8 with 2.3 mol / L dilute sulfuric acid solution, and then Mn was extracted using a P507-C272 mixed extractant to obtain raffinate and a loaded organic phase. The P507-C272 mixed extractant consisted of 12% P507, 13% C272, and 75% sulfonated kerosene by mass percentage. The saponification rate was controlled at 55%, and nickel soap was transferred. The O / A ratio was controlled at 1.8:1 for extraction to separate Mn. Then, the loaded organic phase was back-extracted using a 2.3 mol / L dilute sulfuric acid solution, and the resulting back-extract was a crude manganese sulfate solution. The raffinate was then purified using a P204 extractant to obtain a purified solution. Cobalt was then recovered using a P507 extractant (i.e., the second extraction) to obtain a refined cobalt sulfate solution and a nickel-magnesium raffinate. Finally, the nickel-magnesium raffinate was subjected to nickel-magnesium separation (i.e., third extraction) using C272 extractant to obtain a purified nickel sulfate solution. The yield of metallic nickel was 99.36%, and the yield of metallic cobalt was 99.74%.

[0153] (4) The manganese slag (mainly manganese dioxide) obtained in step (1) was subjected to reduction leaching at 85°C using concentrated sulfuric acid solution and hydrogen peroxide (mass fraction 27%). The hydrogen peroxide solution was added over a period of 4 hours, with 10 mL of 27% hydrogen peroxide solution added for every 1 g of manganese. After the hydrogen peroxide solution was added, the reaction was continued at this temperature for another 1 hour to obtain the reduction leachate and the leaching residue. The main components of the manganese slag, the main components of the reduction leachate, the main components of the leaching residue, and the leaching rates of each element are shown in Table 3.

[0154] Table 3. Main components of manganese slag, reducing leachate, and leaching residue, and leaching rates of each element.

[0155] element Co Ni Cu Fe Ca Mg Mn Zn Na Al Si Manganese slag (wt.%) 1.95 2.35 0.11 0.86 0.10 0.06 55.46 0.36 0.14 0.60 0.11 Reduced leachate (g / L) 4.33 5.22 0.24 1.83 0.16 0.12 123.07 0.80 0.27 1.31 0.24 Leaching residue (wt.%) 0.03 0.04 0.00 0.35 0.26 0.03 0.76 0.00 0.16 0.08 0.06 Leaching rate (%) 99.85 99.82 99.98 95.69 73.07 95.43 99.86 99.97 87.86 98.59 94.52

[0156] The above-mentioned reducing leachate was mixed with sodium carbonate solution (mass concentration of 250 g / L, the amount added was adjusted according to the pH value at the end of the iron removal reaction) in a parallel flow (i.e., added simultaneously) for iron removal reaction (convective iron removal process). The time for adding the solution in a parallel flow was controlled at 4 h, the temperature of the iron removal reaction was 95℃, and the temperature was maintained for another 3 h after the addition was completed. Then it was filtered to obtain jaundice iron alum residue and iron-removed liquid. The main components of the reducing leachate, the main components of the iron-removed liquid and their pH, and the precipitation rate of each element are shown in Table 4.

[0157] Table 4. Main components of the reducing leachate, main components of the iron-removed solution, pH, and precipitation rate.

[0158] element Co Ni Cu Fe Mn Al Si Sc pH Reduced leachate 4.33 5.22 0.24 1.83 123.07 1.31 0.24 0.03 0.88 Iron-removed liquid (g / L) 4.69 5.54 0.13 0.010 133.68 0.20 0.16 0.023 3.98 Sedimentation rate (%) 0.38 2.43 48.91 99.49 0.07 85.77 40.1 20.57 /

[0159] (5) The iron-removed liquid obtained in step (4) is mixed with the crude manganese sulfate solution obtained in step (3) and then fed into the calcium and magnesium removal process (the mixed solution is referred to as the calcium and magnesium removal pre-liquid). Solid manganese fluoride is added to it, and the amount of manganese fluoride added is 100 times the theoretical total mass of the reaction with calcium and magnesium ions. The final pH of the reaction is 5.5, the system temperature during the reaction is 88℃, and the reaction time is 7h. Then, the mixture is filtered to obtain the defluorinated slag and the calcium and magnesium removal liquid. The main components and pH of the calcium and magnesium removal pre-liquid and the calcium and magnesium removal liquid are shown in Table 5.

[0160] Table 5. Main components and pH values ​​of the pre- and post-calcium and magnesium removal solutions.

[0161] element Co Ni Cu Fe Ca Mg Mn Zn F pH Pre-calcium and magnesium removal solution (g / L) 4.69 5.54 0.13 0.010 0.19 0.13 133.68 0.28 0.005 4.01 Solution after calcium and magnesium removal (g / L) 4.32 5.34 0.075 0.001 0.0021 0.0038 129.96 0.24 9.87 5.52

[0162] (6) Anhydrous aluminum sulfate crystals were added to the calcium and magnesium removal solution obtained in step (5) according to a molar ratio of F to Al of 4.5:1 for defluorination treatment. The defluorination treatment temperature was 82℃ and the reaction time was 5h. After filtration, the defluorinated solution and crude aluminum fluoride were obtained. The main components and pH of the calcium and magnesium removal solution and the defluorination solution are shown in Table 6.

[0163] Table 6. Main components and pH of the solutions after calcium and magnesium removal and fluoride removal.

[0164] element F Al Co Ni Mn pH Solution after calcium and magnesium removal (g / L) 9.87 0.0025 4.32 5.34 129.96 5.52 Defluoridated solution (g / L) 0.26 0.29 3.52 4.43 116.57 6.07

[0165] (7) Add manganese sulfide to the defluorinated liquid obtained in step (6) for copper and zinc removal treatment (room temperature, 25℃). The amount of manganese sulfide added is 13 times the theoretical total mass of manganese sulfide required for reaction with copper and zinc ions. The copper and zinc removal treatment time is 2 hours. After filtration, the copper and zinc removed liquid is obtained. Add 10% sodium hydroxide solution to the copper and zinc removed liquid until the pH of the mixed system is 8.1 for Co, Ni, Al, and Sc removal treatment. After stirring for 2 hours, the solid and liquid are separated to obtain the heavy-duty removed liquid. The main components and their pH values ​​of the defluorinated liquid, the copper and zinc removed liquid, and the heavy-duty removed liquid are shown in Table 7.

[0166] Table 7. Main components and pH values ​​of the defluorination solution, copper-zinc removal solution, and heavy metal removal solution.

[0167] element Cu Zn Co Ni Al Sc pH Defluoridated solution (g / L) 0.05 0.23 3.52 4.43 0.29 0.095 6.07 Copper and zinc removal solution (g / L) 0.0005 0.0044 0.66 1.32 0.031 0.0016 6.5 Liquid after weight removal (g / L) 0.0003 0.001 0.0005 0.002 0.0005 0.0005 8.1

[0168] (8) After adjusting the pH of the deweighted solution obtained in step (7) to 6.0 with 1 mol / L dilute sulfuric acid solution, Si, F, and P were removed using zirconium ion-modified resin (LSC-860). The resin impurity removal flow rate was 2.0 BV / h to obtain a refined manganese sulfate solution. The deweighted solution, its pH, and the main components and pH values ​​of the refined manganese sulfate solution are shown in Table 8. The contents of other elements in the refined manganese sulfate solution are shown in Table 9. The yield of metallic manganese was 95.91%.

[0169] Table 8. Main components and pH values ​​of the de-gravity solution and refined manganese sulfate solution.

[0170] element Cu Zn Co Ni Liquid after weight removal (g / L) 0.05 0.23 3.52 4.43 Refined manganese sulfate solution (g / L) 0.0005 0.0044 0.66 1.32

[0171] Table 9. Content of other elements in refined manganese sulfate solution

[0172] element Mn Co Ni Cu Fe Zn Ca Mg Al Sc Content (g / L) 109.82 0.0005 0.0015 0.0005 0.0002 0.0009 0.0005 0.0021 0.0005 0.0005

[0173] Example 2

[0174] The method for preparing precursor sulfate solutions (cobalt sulfate solution, nickel sulfate solution, and manganese sulfate solution) using nickel-cobalt hydroxide intermediates provided in this embodiment includes the following steps, the flowchart of which can be found here. Figure 1 As shown:

[0175] (1) Obtain nickel-cobalt hydroxide intermediate, the chemical composition of which is shown in Table 10 below.

[0176] Table 10 Chemical composition of nickel-cobalt hydroxide intermediate

[0177] <![CDATA[H2O]]> Ni Co Mn Cu Fe Ca Mg Zn Al Si Sc F 50.34％ 1.59％ 21.98％ 0.19％ 3.49％ 0.08％ 0.032％ 0.02％ 0.07％ 0.80％ 0.10％ 0.10％ 0.005％

[0178] According to the liquid-to-solid ratio (L / S) of nickel-cobalt hydroxide intermediate and pure water = 1.8 g / ml, pure water and nickel-cobalt hydroxide intermediate were mixed and slurried. Then, concentrated sulfuric acid solution was added, and the reaction was maintained at 85℃ for 3 hours. During the reaction, the pH of the system was controlled at 1.0. The pH of the acid leaching reaction endpoint was 1.0. The mass concentration of nickel in the leachate obtained after acid leaching was 96.14 g / L. A cationic polyacrylamide solution (mass fraction 0.5‰) was added to the leachate at an addition rate of 10 mg / L (i.e., 10 mg of polymeric cationic surfactant solution per L of leachate). After stirring for 30 min, the mixture was allowed to stand for 30 min to settle, and then filtered to obtain a cobalt-nickel-manganese sulfate mixed solution and manganese slag. The contents of cobalt, nickel, copper, manganese, silicon, and scandium in the cobalt-nickel-manganese sulfate mixed solution and manganese slag, as well as the leaching rates of cobalt, nickel, copper, manganese, silicon, and scandium, are shown in Table 11.

[0179] Table 11 Main composition and leaching rate of each element in cobalt-nickel-manganese sulfate mixed solution and manganese slag

[0180] element Co Ni Cu Mn Si Sc Nickel-cobalt-manganese mixed solution (g / L) 6.71 94.80 0.80 6.92 0.34 0.13 Manganese slag (wt.%) 1.20％ 4.51％ 0.16％ 48.68％ 0.14％ 0.03％ Leaching rate (%) 97.05％ 99.20％ 96.70％ 45.60％ 93.70％ 96.50％

[0181] (2) Using the slurry of nickel-cobalt hydroxide intermediate obtained in step (2) of Example 1, the pH of the mixed solution of cobalt-nickel-manganese sulfate obtained in step (1) was adjusted to 5.5, and then filtered to obtain the precipitate and the precipitate residue. The precipitate residue was mixed with dilute sulfuric acid solution and leached to obtain a leachate. The leachate was then mixed with the nickel-cobalt hydroxide intermediate to obtain a slurry of nickel-cobalt hydroxide intermediate, which can be reused.

[0182] (3) The precipitate obtained in step (2) was adjusted to pH 2.5 with a 2.2 mol / L dilute sulfuric acid solution, and then Mn was extracted using a P507-C272 mixed extractant to obtain raffinate and a loaded organic phase. The P507-C272 mixed extractant consisted of 10% P507, 10% C272, and 80% sulfonated kerosene by mass percentage. The saponification rate was controlled at 50%, and nickel soap was transferred. The O / A ratio was controlled at 1.5:1 for extraction to separate Mn. Then, the loaded organic phase was back-extracted using a 2.2 mol / L dilute sulfuric acid solution, and the resulting back-extract was a crude manganese sulfate solution. The raffinate was then purified using a P204 extractant to obtain a purified solution. Cobalt was then recovered using a P507 extractant (i.e., the second extraction) to obtain a refined cobalt sulfate solution and a nickel-magnesium raffinate. Finally, the nickel-magnesium raffinate was subjected to nickel-magnesium separation (i.e., third extraction) using C272 extractant to obtain a purified nickel sulfate solution. The yield of metallic nickel was 98.62%, and the yield of metallic cobalt was 98.49%.

[0183] (4) The manganese slag (mainly manganese dioxide) obtained in step (1) was subjected to reduction leaching at 80°C using concentrated sulfuric acid solution and hydrogen peroxide (mass fraction 30%). The hydrogen peroxide solution was added over a period of 3 hours, with 8 mL of 30% hydrogen peroxide solution added for every 1 g of manganese. After the hydrogen peroxide solution was added, the reaction was continued at this temperature for another hour to obtain the reduction leachate and the leaching residue. The main components of the manganese slag, the main components of the reduction leachate, the main components of the leaching residue, and the leaching rates of each element are shown in Table 12.

[0184] Table 12 Main components of manganese slag, reducing leachate, and leaching residue, and leaching rates of each element.

[0185] element Co Ni Cu Fe Ca Mg Mn Zn Na Al Si Manganese slag (wt.%) 1.20 4.51 0.16 0.86 0.10 0.06 48.68 0.10 0.14 0.60 0.14 Reduced leachate (g / L) 2.78 10.19 0.35 1.91 0.15 0.12 113.07 0.20 0.07 1.36 0.23 Leaching residue (wt.%) 0.06 1.38 0.13 0.42 0.38 0.05 0.65 1.42 1.17 0.15 0.38 Leaching rate (%) 99.52 97.14 92.64 95.48 64.71 92.38 99.88 86.66 21.47 97.64 73.72

[0186] The above-mentioned reducing leachate was mixed with sodium carbonate solution (mass concentration of 250 g / L, the amount added was adjusted according to the pH value at the end of the iron removal reaction) in a parallel flow (i.e., added simultaneously) for iron removal reaction (convective iron removal process). The time for adding the solution in a parallel flow was controlled at 3 h, the temperature of the iron removal reaction was 100℃, and the temperature was maintained for another 2 h after the addition was completed. Then it was filtered to obtain jaundice iron alum residue and iron-removed liquid. The main components of the reducing leachate, the main components of the iron-removed liquid and their pH, and the precipitation rate of each element are shown in Table 13.

[0187] Table 13 Main components of reducing leachate, main components of iron-removed solution, pH, and precipitation rate

[0188] element Co Ni Cu Fe Mn Al Si Sc pH Reduced leachate 2.78 10.19 0.35 1.91 113.07 1.36 0.23 0.06 0.76 Iron-removed liquid (g / L) 2.77 8.07 0.12 0.003 116.69 0.01 0.16 0.049 4.32 Sedimentation rate (%) 4.53 23.98 67.12 99.84 0.93 99.43 34.64 27.06 /

[0189] (5) The iron-removed liquid obtained in step (4) is mixed with the crude manganese sulfate solution obtained in step (3) and then fed into the calcium and magnesium removal process (the mixed solution is referred to as the calcium and magnesium removal pre-liquid). Solid manganese fluoride is added to it, and the amount of manganese fluoride added is 110 times the theoretical total mass of the reaction with calcium and magnesium ions. The final pH of the reaction is 5.0, the system temperature during the reaction is 95℃, and the reaction time is 6h. Then, the mixture is filtered to obtain the defluorinated slag and the calcium and magnesium removal liquid. The main components and pH of the calcium and magnesium removal pre-liquid and the calcium and magnesium removal liquid are shown in Table 14.

[0190] Table 14 Main components and pH values ​​of the pre- and post-calcium and magnesium removal solutions.

[0191] element Co Ni Cu Fe Ca Mg Mn Zn F pH Pre-calcium and magnesium removal solution (g / L) 2.77 8.07 0.12 0.003 0.15 0.12 116.69 0.20 0.005 4.32 Solution after calcium and magnesium removal (g / L) 2.12 6.76 0.07 0.003 0.0025 0.0045 109.88 0.18 10.15 5.36

[0192] (6) Polyaluminum sulfate was added to the calcium and magnesium removal solution obtained in step (5) according to a molar ratio of F to Al of 3.5:1 for defluorination treatment. The defluorination treatment temperature was 75℃ and the reaction time was 4h. After filtration, the defluorinated solution and crude aluminum fluoride were obtained. The main components and pH of the calcium and magnesium removal solution and the defluorination solution are shown in Table 15.

[0193] Table 15 Main components and pH of the solutions after calcium and magnesium removal and fluoride removal.

[0194] element F Al Co Ni Mn pH Solution after calcium and magnesium removal (g / L) 10.15 0.0037 2.12 6.76 109.88 5.36 Defluoridated solution (g / L) 0.34 0.13 1.93 4.94 105 5.64

[0195] (7) Add sodium sulfide to the defluorinated liquid obtained in step (6) to remove copper and zinc (room temperature, 25℃). The amount of sodium sulfide added is 15 times the theoretical total mass of manganese sulfide required for reaction with copper and zinc ions. The copper and zinc removal treatment time is 2 hours. After filtration, the copper and zinc removed liquid is obtained. Then, add a 10% sodium hydroxide solution to the copper and zinc removed liquid until the pH of the mixed system is 7.5 to remove Co, Ni, Al, and Sc. After stirring and reacting for 4 hours, the solid and liquid are separated to obtain the heavy-duty removed liquid. The main components and their pH values ​​of the defluorinated liquid, the copper and zinc removed liquid, and the heavy-duty removed liquid are shown in Table 16.

[0196] Table 16 Main components and pH values ​​of the defluorination solution, copper-zinc removal solution, and heavy metal removal solution.

[0197] element Cu Zn Co Ni Al Sc pH Defluoridated solution (g / L) 0.045 0.15 1.93 4.94 0.13 0.095 5.64 Copper and zinc removal solution (g / L) 0.0005 0.0037 0.14 0.96 0.018 0.0023 6.43 Liquid after weight removal (g / L) 0.0005 0.0012 0.0019 0.0013 0.0008 0.0005 7.5

[0198] (8) After adjusting the pH of the deweighted solution obtained in step (7) to 6.5 with a 1.5 mol / L dilute sulfuric acid solution, Si, F, and P were removed using Haipu HP4800 modified resin. The resin impurity removal flow rate was 1.5 BV / h to obtain a refined manganese sulfate solution. The deweighted solution, its pH, and the main components and pH values ​​of the refined manganese sulfate solution are shown in Table 17. The contents of other elements in the refined manganese sulfate solution are shown in Table 18. The yield of metallic manganese was 95.22%.

[0199] Table 17 Main components and pH values ​​of the de-gravity solution and purified manganese sulfate solution

[0200] element Si F P pH Liquid after weight removal (g / L) 0.014 0.01 0.035 6.5 Refined manganese sulfate solution (g / L) 0.0005 0.0005 0.001 6.33

[0201] Table 18 Content of other elements in refined manganese sulfate solution

[0202] element Mn Co Ni Cu Fe Zn Ca Mg Al Sc Content (g / L) 104.18 0.0005 0.0019 0.0004 0.0003 0.0007 0.0005 0.0026 0.0005 0.0005

[0203] Example 3

[0204] The method for preparing precursor sulfate solutions (cobalt sulfate solution, nickel sulfate solution, and manganese sulfate solution) using nickel-cobalt hydroxide intermediates provided in this embodiment includes the following steps:

[0205] (1) Obtain nickel-cobalt hydroxide intermediate, the chemical composition of which is shown in Table 19 below.

[0206] Table 19 Chemical composition of nickel-cobalt hydroxide intermediates

[0207] <![CDATA[H2O]]> Co Ni Cu Mn Si Sc Fe Ca Mg Zn Al F 48.36％ 1.66％ 20.71％ 0.20％ 3.63％ 0.08％ 0.033％ 0.02％ 0.07％ 0.83％ 0.20％ 0.11％ 0.004％

[0208] According to the liquid-to-solid ratio (L / S) of nickel-cobalt hydroxide intermediate and pure water = 2.5 g / ml, pure water and nickel-cobalt hydroxide intermediate were mixed and slurried. Then, concentrated sulfuric acid solution was added, and the reaction was maintained at 80℃ for 6 hours. During the reaction, the pH of the system was controlled at 0.5. The pH of the acid leaching reaction endpoint was 0.5. The mass concentration of nickel in the leachate obtained after acid leaching was 87.3 g / L. A cationic polyacrylamide solution (mass fraction 1.5‰) was added to the leachate at an addition rate of 5 mg / L (i.e., 5 mg of polymeric cationic surfactant solution per L of leachate). After stirring for 10 min, the mixture was allowed to stand for 60 min to settle, and then filtered to obtain a cobalt-nickel-manganese sulfate mixed solution and manganese slag. The contents of cobalt, nickel, copper, manganese, silicon, and scandium in the cobalt-nickel-manganese sulfate mixed solution and manganese slag, as well as the leaching rates of cobalt, nickel, copper, manganese, silicon, and scandium, are shown in Table 20.

[0209] Table 20 Main composition and leaching rate of each element in cobalt-nickel-manganese sulfate mixed solution and manganese slag.

[0210] element Co Ni Cu Mn Si Sc Nickel-cobalt-manganese mixed solution (g / L) 6.52 89.65 0.86 6.52 0.33 0.14 Manganese slag (wt.%) 0.75％ 0.49％ 0.09％ 49.08％ 0.14％ 0.01％ Leaching rate (%) 98.03％ 99.55％ 98.10％ 41.33％ 92.72％ 98.14％

[0211] (2) Using the slurry of nickel-cobalt hydroxide intermediate obtained in step (2) of Example 1, the pH of the mixed solution of cobalt-nickel-manganese sulfate obtained in step (1) was adjusted to 6.5, and then filtered to obtain the precipitate and the precipitate residue. The precipitate residue was mixed with dilute sulfuric acid solution and leached to obtain a leachate. The leachate was then mixed with the nickel-cobalt hydroxide intermediate to obtain a slurry of nickel-cobalt hydroxide intermediate, which can be reused.

[0212] (3) The precipitate obtained in step (2) was adjusted to pH 3.0 with 2.5 mol / L dilute sulfuric acid solution, and then Mn was extracted using a P507-C272 mixed extractant to obtain raffinate and loaded organic phase. The P507-C272 mixed extractant was composed of 15% P507, 15% C272 and 70% sulfonated kerosene by mass percentage. The saponification rate was controlled at 53% to convert to nickel soap. The O / A ratio was controlled at 2:1 for extraction to separate Mn. Then, the loaded organic phase was back-extracted using a 2.5 mol / L dilute sulfuric acid solution to obtain crude manganese sulfate solution. The raffinate was then purified using P204 extractant to obtain purified solution. Cobalt was recovered using P507 extractant (i.e., the second extraction) to obtain refined cobalt sulfate solution and nickel-magnesium raffinate. Finally, the nickel-magnesium raffinate was subjected to nickel-magnesium separation (i.e., third extraction) using C272 extractant to obtain a purified nickel sulfate solution. The yield of metallic nickel was 98.45%, and the yield of metallic cobalt was 98.78%.

[0213] (4) The manganese slag (mainly manganese dioxide) obtained in step (1) was subjected to reduction leaching at 75°C using concentrated sulfuric acid solution and hydrogen peroxide (mass fraction 30%). The hydrogen peroxide solution was added over a period of 3 hours, with 9 mL of 30% hydrogen peroxide solution added for every 1 g of manganese. After the hydrogen peroxide solution was added, the reaction was continued at this temperature for another hour to obtain the reduction leachate and the leaching residue. The main components of the manganese slag, the main components of the reduction leachate, the main components of the leaching residue, and the leaching rates of each element are shown in Table 21.

[0214] Table 21 Main components of manganese slag, reducing leachate, and leaching residue, and leaching rates of each element.

[0215] element Co Ni Cu Fe Ca Mg Mn Zn Na Al Si Manganese slag (wt.%) 0.75 2.15 0.09 0.86 0.10 0.06 49.08 0.10 0.14 0.60 0.14 Reduced leachate (g / L) 2.92 4.82 1.16 1.67 0.05 0.07 119.85 0.23 0.07 1.41 0.12 Leaching residue (wt.%) 0.10 0.04 0.04 0.83 0.13 0.14 5.17 0.01 0.27 0.31 0.37 Leaching rate (%) 99.76 98.06 92.37 91.63 42.77 85.01 99.83 92.59 12.36 94.75 61.39

[0216] The above-mentioned reducing leachate was mixed with sodium carbonate solution (mass concentration of 230 g / L, the amount added was adjusted according to the pH value at the end of the iron removal reaction) in a parallel flow (i.e., added simultaneously) for iron removal reaction (convective iron removal process). The time for adding the solution in a parallel flow was controlled at 3.5 h, the temperature of the iron removal reaction was 98℃, and the temperature was maintained for another 5 h after the addition was completed. Then it was filtered to obtain jaundice iron alum residue and iron-removed liquid. The main components of the reducing leachate, the main components of the iron-removed liquid and their pH, and the precipitation rate of each element are shown in Table 22.

[0217] Table 22 Main components of reducing leachate, main components of iron-removed solution, pH, and precipitation rate

[0218] element Co Ni Cu Fe Mn Al Si Sc pH Reduced leachate 2.92 4.82 1.16 1.67 119.85 1.41 0.12 0.03 0.91 Iron-removed liquid (g / L) 2.78 3.63 0.37 0.007 120.16 0.01 0.07 0.026 4.58 Sedimentation rate (%) 6.83 26.12 68.96 99.59 1.75 99.6 44.07 21.15 /

[0219] (5) The iron-removed liquid obtained in step (4) is mixed with the crude manganese sulfate solution obtained in step (3) and then fed into the calcium and magnesium removal process (the mixed solution is referred to as the calcium and magnesium removal pre-liquid). Solid manganese fluoride is added to it, and the amount of manganese fluoride added is 80 times the theoretical total mass of the reaction with calcium and magnesium ions. The final pH of the reaction is 6.0, the system temperature during the reaction is 80℃, and the reaction time is 8h. Then, the mixture is filtered to obtain the defluorinated slag and the calcium and magnesium removal liquid. The main components and pH of the calcium and magnesium removal pre-liquid and the calcium and magnesium removal liquid are shown in Table 23.

[0220] Table 23 Main components and pH values ​​of the pre- and post-calcium and magnesium removal solutions.

[0221] element Co Ni Cu Fe Ca Mg Mn Zn F pH Pre-calcium and magnesium removal solution (g / L) 2.78 3.63 0.37 0.001 0.05 0.07 120.16 0.23 0.004 4.58 Solution after calcium and magnesium removal (g / L) 2.55 3.13 0.19 0.003 0.0005 0.0034 113.56 0.16 11.82 5.99

[0222] (6) Anhydrous aluminum sulfate crystals were added to the calcium and magnesium removal solution obtained in step (5) according to a molar ratio of F to Al of 5.0:1 for defluorination treatment. The defluorination treatment temperature was 90℃ and the reaction time was 6h. After filtration, the defluorinated solution and crude aluminum fluoride were obtained. The main components and pH of the calcium and magnesium removal solution and the defluorination solution are shown in Table 24.

[0223] Table 24 Main components and pH of the solutions after calcium and magnesium removal and fluoride removal.

[0224] element F Al Co Ni Mn pH Solution after calcium and magnesium removal (g / L) 11.82 0.0055 2.55 3.13 113.56 5.79 Defluoridated solution (g / L) 0.41 0.16 1.93 2.94 105 5.99

[0225] (7) Add ammonium sulfide to the defluorinated liquid obtained in step (6) to perform copper and zinc removal treatment (room temperature, 25℃). The amount of ammonium sulfide added is 12 times the theoretical total mass of manganese sulfide required for reaction with copper and zinc ions. The copper and zinc removal treatment time is 2 hours. After filtration, the copper and zinc removed liquid is obtained. Then, add 10% sodium hydroxide solution to the copper and zinc removed liquid until the pH of the mixed system is 9.0 to perform Co, Ni, Al, and Sc removal treatment. After stirring and reacting for 2 hours, the solid and liquid are separated to obtain the heavy-duty removed liquid. The main components and their pH values ​​of the defluorinated liquid, the copper and zinc removed liquid, and the heavy-duty removed liquid are shown in Table 25.

[0226] Table 25 Main components and pH values ​​of the defluorination solution, copper-zinc removal solution, and heavy metal removal solution.

[0227] element Cu Zn Co Ni Al Sc pH Defluoridated solution (g / L) 0.15 0.13 1.93 2.94 0.16 0.095 5.99 Copper and zinc removal solution (g / L) 0.0005 0.0015 0.49 0.67 0.005 0.001 6.71 Liquid after weight removal (g / L) 0.0001 0.0008 0.0005 0.0005 0.0001 0.0005 9.0

[0228] (8) After adjusting the pH of the deweighted solution obtained in step (7) to 5.5 with a 1.1 mol / L dilute sulfuric acid solution, Si, F, and P were removed using a zirconium ion-modified resin (LSC-860). The resin impurity removal flow rate was 2.5 BV / h to obtain a refined manganese sulfate solution. The deweighted solution, its pH, and the main components and pH values ​​of the refined manganese sulfate solution are shown in Table 26. The contents of other elements in the refined manganese sulfate solution are shown in Table 27. The yield of metallic manganese was 94.62%.

[0229] Table 26 Main components and pH values ​​of the de-gravity solution and refined manganese sulfate solution

[0230] element Si F P pH Liquid after weight removal (g / L) 0.002 0.066 0.042 5.5 Refined manganese sulfate solution (g / L) 0.0006 0.0008 0.0013 5.45

[0231] Table 27 Content of other elements in refined manganese sulfate solution

[0232] element Mn Co Ni Cu Fe Zn Ca Mg Al Sc Content (g / L) 100.21 0.0005 0.0017 0.0005 0.0001 0.0005 0.0005 0.0019 0.0002 0.0005

[0233] Example 4

[0234] The method for preparing precursor sulfate solutions (cobalt sulfate solution, nickel sulfate solution and manganese sulfate solution) using nickel-cobalt hydroxide intermediates provided in this embodiment is basically the same as that in Example 1, except that in step (3), the proportion of P507-C272 mixed extractant by mass percentage is: 12% P507, 15% C272 and 73% sulfonated kerosene.

[0235] Example 5

[0236] The method for preparing precursor sulfate solutions (cobalt sulfate solution, nickel sulfate solution and manganese sulfate solution) using nickel-cobalt hydroxide intermediates provided in this embodiment is basically the same as that in Example 1, except that: in step (3), the saponification rate is controlled at 50% and O / A = 2:1.

[0237] Example 6

[0238] The method for preparing precursor sulfate solutions (cobalt sulfate solution, nickel sulfate solution and manganese sulfate solution) using nickel-cobalt hydroxide intermediates provided in this embodiment is basically the same as that in Example 1, except that in step (1), the cationic polyacrylamide solution is replaced with an equal mass fraction of nonionic polyacrylamide solution.

[0239] Comparative Example 1

[0240] The method provided in this comparative example for preparing precursor sulfate solutions (cobalt sulfate solution, nickel sulfate solution and manganese sulfate solution) using nickel-cobalt hydroxide intermediates is basically the same as that in Example 1, except that in step (3), the P507-C272 mixed extractant is replaced with 13% C272 and 87% sulfonated kerosene by mass percentage.

[0241] Comparative Example 2

[0242] The method provided in this comparative example for preparing precursor sulfate solutions (cobalt sulfate solution, nickel sulfate solution and manganese sulfate solution) using nickel-cobalt hydroxide intermediates is basically the same as that in Example 1, except that in step (3), the P507-C272 mixed extractant is replaced with 12% P507 and 88% sulfonated kerosene by mass percentage.

[0243] Comparative Example 3

[0244] The method provided in this comparative example for preparing precursor sulfate solutions (cobalt sulfate solution, nickel sulfate solution and manganese sulfate solution) using nickel-cobalt hydroxide intermediates is basically the same as that in Example 1, except that in step (3), the P507-C272 mixed extractant is in the following proportions by mass percentage: 20% P507, 20% C272 and 50% sulfonated kerosene.

[0245] The prices are as follows: C272: 150,000 yuan / ton, P507: 35,000 yuan / ton. During the extraction process, high concentrations of C272 used alone are detrimental to phase separation and result in prolonged clarification time. Higher concentrations of C272 in the mixed extractant further hinder phase separation; therefore, C272 used alone requires low concentrations, but low concentrations lead to reduced processing capacity. This invention utilizes a mixed extractant, adding a portion of P507 to increase the overall concentration of the organic phase, thereby improving processing capacity while maintaining a low Ca extraction rate, reducing production costs, and increasing economic benefits.

[0246] The main difference between Comparative Example 1, Comparative Example 2, and Comparative Example 3 is the different proportions of organic content. The higher the C272 content, the lower the Ca content in the manganese liquid, but the cost is too high. On the other hand, using only P507 to extract the Ca content results in too high a content. At the same time, when using sulfuric acid for back-extraction, calcium sulfate slag will be formed in the extraction tank, causing blockage of equipment and pipelines.

[0247] Comparative Example 4

[0248] The method provided in this comparative example for preparing precursor sulfate solutions (cobalt sulfate solution, nickel sulfate solution and manganese sulfate solution) using nickel-cobalt hydroxide intermediates is basically the same as that in Example 1, except that cationic polyacrylamide solution is not added in step (1).

[0249] Example 1 added a flocculant before filtration, increasing the flocculation effect of the slag in the solution and improving the filtration speed. For the same volume of leached slurry, the filtration speed of Example 1 was 20 times that of Comparative Example 4. In Comparative Example 4, no flocculant was added, and the fine MnO2 particles in the slag caused filter penetration and filtration failure, increasing the pressure and sealing requirements on the filtration equipment. This is detrimental to production use. Various limitations also make the acid leaching process for separating nickel-cobalt and manganese slag difficult to operate, hindering process optimization.

[0250] Comparative Example 5

[0251] The method provided in this comparative example for preparing precursor sulfate solutions (cobalt sulfate solution, nickel sulfate solution and manganese sulfate solution) using nickel-cobalt hydroxide intermediates is basically the same as that in Example 1, except that: in step (8), no modified resin is used, that is, no Si, F and P removal treatment is performed.

[0252] This comparative example did not undergo resin treatment to remove Si, F, and P. The resulting manganese solution had high levels of impurities in Si, F, and P, exceeding the acceptable impurity levels. It could not be directly used in precursor production, as Si and P might be introduced into the precursor product, leading to product defects. High F content could also corrode and damage equipment, increasing maintenance costs. The Si, F, and P contents and pH values ​​of the refined manganese sulfate solutions obtained in Example 1 and Comparative Example 5 are shown in Table 28.

[0253] Table 28. Si, F, P content and pH of purified manganese sulfate solution in Example 1 and Comparative Example 5

[0254] Group Si F P pH Comparative Example 5 0.005 0.085 0.054 6 Example 1 0.0005 0.0005 0.001 6.02

[0255] Although the present invention has been illustrated and described with specific embodiments, it should be understood that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; those skilled in the art should understand that modifications can be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein, without departing from the spirit and scope of the present invention; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention; therefore, this means that all such substitutions and modifications that fall within the scope of the present invention are included in the appended claims.

Claims

1. A method for preparing a sulfate solution for a precursor using a nickel-cobalt hydroxide intermediate, characterized in that, Includes the following steps: (a) The intermediate nickel-cobalt hydroxide was mixed with sulfuric acid solution and acid leached. Then, a flocculant was added to it for sedimentation, followed by solid-liquid separation to obtain a mixed solution of cobalt-nickel-manganese sulfate and manganese slag. (b) Adjust the pH of the cobalt-nickel-manganese sulfate mixed solution to ≥5.5, and then perform solid-liquid separation to obtain the post-precipitation liquid and the precipitate residue; (c) After adjusting the pH of the precipitated liquid to 2.0-3.5, it is mixed with a composite extractant containing P507 and C272 and subjected to a first extraction to obtain a raffinate and a loaded organic phase; the loaded organic phase is back-extracted to obtain a crude manganese sulfate solution; the raffinate is mixed with P204 extractant for impurity removal to obtain a purified liquid; the purified liquid is subjected to a second extraction using P507 extractant to obtain a refined cobalt sulfate solution and a nickel-magnesium raffinate; the nickel-magnesium raffinate is subjected to a third extraction using C272 extractant to obtain a refined nickel sulfate solution; (d) The manganese slag is mixed with sulfuric acid solution and reducing agent and subjected to reduction leaching to obtain reduction leaching solution; The reducing leachate was mixed with sodium carbonate solution and subjected to an iron removal reaction, followed by solid-liquid separation to obtain yellow sodium iron alum residue and iron-removed liquid. (e) After mixing the iron-removed liquid with the crude manganese sulfate solution, manganese fluoride is added to remove calcium and magnesium; then solid-liquid separation is performed to obtain fluoride-removed slag and calcium and magnesium-removed liquid. (f) The calcium and magnesium removed liquid is mixed with an aluminum source and subjected to defluorination treatment, followed by solid-liquid separation to obtain the defluorinated liquid and crude aluminum fluoride; (g) The defluorinated liquid is mixed with sulfide and subjected to copper and zinc removal treatment. After solid-liquid separation, a copper and zinc removed liquid is obtained. An alkaline solution is added to the copper and zinc removed liquid to remove Co, Ni, Al, and Sc. Then, solid-liquid separation is performed to obtain a heavy removal liquid. (h) After adjusting the pH of the deweighted solution to acidic, Si, F and P are removed by using a modified resin to obtain a refined manganese sulfate solution.

2. The method for preparing a precursor sulfate solution using a nickel-cobalt hydroxide intermediate according to claim 1, characterized in that, In step (a), at least one of the following conditions must be met: (1) The step of mixing and acid leaching the intermediate nickel-cobalt hydroxide with sulfuric acid solution specifically includes: first mixing the intermediate nickel-cobalt hydroxide with water to form a slurry, and then adding concentrated sulfuric acid solution to it; the liquid-solid ratio of the intermediate nickel-cobalt hydroxide to the water is 1.8~2.5 g / ml; the pH of the acid leaching reaction system and / or the pH of the final reaction point of the acid leaching is 0.5~1.0; (2) The acid leaching temperature is 80~90℃; (3) The acid leaching time is 3~6 hours; (4) The mass concentration of nickel in the leachate obtained after the acid leaching is ≤100g / L; (5) The flocculant includes at least one of alkyl quaternary ammonium salt cationic surfactant solution, ester quaternary ammonium salt cationic surfactant solution and polymeric cationic surfactant solution; the polymeric cationic surfactant solution includes cationic polyacrylamide solution; the mass fraction of the polymeric cationic surfactant solution is 0.5‰~1.5‰; the addition amount of the polymeric cationic surfactant solution is 5~10 mg / L; (6) After adding the flocculant, stir for 10-30 minutes, and then let stand for 30-60 minutes to allow the sedimentation to proceed.

3. The method for preparing a sulfate solution for a precursor using a nickel-cobalt hydroxide intermediate according to claim 1, characterized in that, In step (b), at least one of the following conditions must be met: (1) The adjustment is carried out using a slurry or alkaline solution containing nickel-cobalt hydroxide intermediate; (2) After obtaining the precipitate, the precipitate is mixed with dilute sulfuric acid solution or concentrated sulfuric acid solution and leached to obtain leachate. Then the leachate is mixed with the nickel-cobalt hydroxide intermediate to obtain a slurry of nickel-cobalt hydroxide intermediate.

4. The method for preparing a precursor sulfate solution using a nickel-cobalt hydroxide intermediate according to claim 1, characterized in that, In step (c), at least one of the following conditions must be met: (1) Adjust the pH of the precipitate solution using concentrated or dilute sulfuric acid solution; (2) The composite extractant containing P507 and C272 includes P507 extractant, C272 extractant and solvent in a mass ratio of 10~15:10~15:70~80, wherein the solvent is sulfonated kerosene; (3) The saponification rate of the first extraction is 50%~55%; (4) The ratio of O / A in the first extraction is 1.5~2:1; (5) The supported organic phase is back-extracted using a dilute sulfuric acid solution, wherein the molar concentration of the dilute sulfuric acid solution is 2.2~2.5 mol / L.

5. The method for preparing a precursor sulfate solution using a nickel-cobalt hydroxide intermediate according to claim 1, characterized in that, In step (d), at least one of the following conditions must be met: (1) The sulfuric acid solution includes dilute sulfuric acid solution or concentrated sulfuric acid solution; (2) The reducing agent includes hydrogen peroxide solution; the hydrogen peroxide solution is added over a period of 3-4 hours; after the hydrogen peroxide solution is added, the reaction is continued at a constant temperature for 1 hour. (3) The temperature of the reduction leaching is 70~90℃; (4) The temperature of the iron removal reaction is >90℃; (5) The reducing leachate and the sodium carbonate solution are added simultaneously, and the addition time is controlled to be 3-4 hours; after the addition is completed, the temperature is kept for 2-5 hours to carry out the iron removal reaction; (6) The pH at the end of the iron removal reaction is 4.0~5.

0.

6. The method for preparing a sulfate solution for a precursor using a nickel-cobalt hydroxide intermediate according to claim 1, characterized in that, In step (e), at least one of the following conditions must be met: (1) The amount of manganese fluoride added is 80 to 120 times the theoretical total mass of the reaction with calcium and magnesium ions; (2) The pH at the endpoint of the calcium and magnesium removal treatment is 5.0~6.0; (3) The temperature for the calcium and magnesium removal treatment is 80~95℃; (4) The time for calcium and magnesium removal treatment is 6-8 hours.

7. The method for preparing a sulfate solution for a precursor using a nickel-cobalt hydroxide intermediate according to claim 1, characterized in that, In step (f), at least one of the following conditions must be met: (1) The aluminum source includes at least one of anhydrous aluminum sulfate, aluminum sulfate octadechydrate, and polyaluminum sulfate; (2) Add the aluminum source according to the molar ratio of F to Al of 3.5~5.0:1; (3) The temperature of the defluorination treatment is 75~90℃; (4) The defluorination treatment time is 4~6h.

8. The method for preparing a sulfate solution for a precursor using a nickel-cobalt hydroxide intermediate according to claim 1, characterized in that, In step (g), at least one of the following conditions must be met: (1) The sulfide includes at least one of manganese sulfide, sodium sulfide, hydrogen sulfide, ammonium sulfide and ammonium hydrosulfide; (2) The amount of sulfide added is 10 to 15 times the theoretical total mass of the reaction with copper and zinc ions; (3) The copper and zinc removal treatment time is 1~2 hours; (4) The alkaline solution includes at least one of sodium hydroxide solution, potassium hydroxide solution and ammonia solution; (5) The amount of alkali solution added is such that the pH of the mixed system is 7.5~9.0; (6) The reaction time for the treatment of Co, Ni, Al and Sc is 2 to 4 hours.

9. The method for preparing a sulfate solution for a precursor using a nickel-cobalt hydroxide intermediate according to claim 1, characterized in that, In step (h), at least one of the following conditions must be met: (1) Adjust the pH of the deweighted solution by adding dilute sulfuric acid solution or concentrated sulfuric acid solution; (2) Adjust the pH of the deweighted solution to 5.5-6.5; (3) The flow rate for removing impurities using the modified resin is 1~3 BV / h.

10. The application of the refined cobalt sulfate solution, refined nickel sulfate solution, and refined manganese sulfate solution obtained by the method for preparing precursor sulfate solution using nickel-cobalt hydroxide intermediate as described in any one of claims 1 to 9 in the preparation of positive electrode precursors, positive electrode materials, positive electrode sheets, and secondary batteries.

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