Method for preparing sulfate solution for precursor by using nickel cobalt hydroxide intermediate product and application of sulfate solution

Abstract

The invention relates to the technical field of positive electrode precursors, in particular to a method for preparing a sulfate solution for a precursor by using a cobalt nickel hydroxide intermediate product and application of the sulfate solution. Performing acid leaching on the intermediate product, and then adding a flocculating agent to obtain a cobalt-nickel-manganese mixed solution and manganese slag; extracting the cobalt-nickel-manganese mixed solution and P507-C272, and reversely extracting a loaded organic phase to obtain a crude manganese sulfate solution; performing P204 impurity removal on the raffinate, recovering cobalt by using P507 to obtain a cobalt sulfate solution, and performing C272 nickel-magnesium separation to obtain a nickel sulfate solution; manganese slag is subjected to reduction leaching to obtain reduction leaching liquid, and then the reduction leaching liquid is mixed with a sodium carbonate solution to remove iron to obtain iron-removed liquid; mixing the iron-removed solution with the crude manganese sulfate solution, and removing calcium and magnesium to obtain a calcium-magnesium-removed solution; mixing the calcium and magnesium removed solution with an aluminum source to remove fluorine to obtain a fluorine removed solution; and mixing the fluorine-removed solution with sulfide to remove copper and zinc, adding alkali liquor to obtain a heavy-removed solution, and treating the heavy-removed solution with modified resin to obtain a refined manganese sulfate solution. The method is high in manganese recovery rate and low in treatment cost.

Description

Technical Field

[0001] The present invention relates to the technical field of positive electrode precursors, and in particular to a method for preparing a sulfate solution for a precursor by utilizing a nickel cobalt hydroxide intermediate and an application thereof. Background Art

[0002] Nickel cobalt hydroxide intermediate (MHP) is a mixed hydroxide containing nickel (Ni) and cobalt (Co). It is an important intermediate raw material and is widely used in battery manufacturing and other nickel-cobalt material synthesis fields. MHP is usually prepared from laterite nickel ore through high pressure acid leaching (HPAL). Due to the limitations of its production process and production process, MHP contains more impurities, such as manganese, iron, copper, cobalt, etc.

[0003] In the prior art, manganese is recovered using MHP as raw material, but the recovery rate of manganese is low and the processing cost is high. The reason is that manganese mainly exists in the form of oxides in MHP, and due to its small particle size, the filtration speed of manganese slag is slow. Therefore, in the leaching process of nickel cobalt hydroxide raw materials, most of them adopt the full reduction process, so all manganese ions need to be separated through the P204 extraction line. Due to the presence of Ca ions in the solution, in order to ensure that no calcium sulfate precipitation is produced during the extraction process, the hydrochloric acid stripping process is mainly adopted. In the process of preparing manganese sulfate, an additional extraction line needs to be added to transform it. Therefore, the extraction cost in the manganese recovery process increases. Poor economic efficiency. In addition, some processes use precipitation → dissolution → concentration and crystallization process to recover manganese metal. This process requires a certain crystallization rate (generally 50% to 60%) to be controlled during the concentration process, resulting in a low direct recovery rate of Mn metal, and a large amount of metal circulates in the crystallization system, resulting in increased costs.

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

[0005] The first object of the present invention is to provide a method for preparing a sulfate solution for a precursor using a nickel cobalt hydroxide intermediate, which has a high recovery rate for manganese and low processing cost. Specifically, the nickel sulfate, cobalt, and manganese mixed solution obtained after acid leaching separates most of the manganese ions under the action of the P507-C272 composite extractant. The use of the P507 extractant in this process can increase the load of the extraction process. At the same time, the Ca ions are left in the raffinate during this process, which can achieve the purpose of using sulfuric acid back extraction without producing calcium sulfate slag. In addition, the use of P507-C272 synergistic extraction can increase the total concentration of the extractant, use P507 to appropriately improve the performance of the extractant, reduce the reaction temperature, speed up the phase separation rate, and improve the saponification rate of the extraction process. Improve the utilization rate of the extractant, without affecting the overall effect of the extraction process, improve the extraction line processing capacity (processing capacity), and reduce production costs.

[0006] The second object of the present 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 purpose of the present invention, the following technical solutions are particularly adopted:

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

[0009] (a) mixing the nickel cobalt hydroxide intermediate with a sulfuric acid solution and acid leaching, then adding a flocculant thereto for sedimentation, and then separating the solid from the liquid to obtain a cobalt nickel manganese sulfate mixed solution and a manganese slag;

[0010] (b) adjusting the pH of the cobalt-nickel-manganese sulfate mixed solution to ≥5.5, and then separating the solid and the liquid to obtain a precipitated liquid and a precipitated residue;

[0011] (c) adjusting the pH of the precipitated liquid to 2.0-3.5, mixing it with a composite extractant containing P507 and C272 and performing a first extraction to obtain a raffinate and a loaded organic phase; stripping the loaded organic phase to obtain a crude manganese sulfate solution; mixing the raffinate with a P204 extractant to remove impurities to obtain a de-impurified liquid; performing a second extraction on the de-impurified liquid using a P507 extractant to obtain a refined cobalt sulfate solution and a nickel-magnesium raffinate; performing a third extraction on the nickel-magnesium raffinate using a C272 extractant to obtain a refined nickel sulfate solution;

[0012] (d) mixing the manganese slag with a sulfuric acid solution and a reducing agent and performing reduction leaching to obtain a reduction leaching solution; mixing the reduction leaching solution with a sodium carbonate solution and performing a deironing reaction, followed by solid-liquid separation to obtain yellow sodium ferroaluminate slag and a deironing solution;

[0013] (e) mixing the de-ironized liquid with the crude manganese sulfate solution, adding manganese fluoride thereto to remove calcium and magnesium; then performing solid-liquid separation to obtain de-fluorinated slag and de-calcified and magnesium-removed liquid;

[0014] (f) mixing the decalcified and magnesium-free liquid with an aluminum source and performing a defluorination treatment, and then performing solid-liquid separation to obtain a defluorinated liquid and crude aluminum fluoride;

[0015] (g) mixing the defluorinated liquid with sulfide and performing a copper-zinc removal treatment, and obtaining a copper-zinc removal liquid after solid-liquid separation; adding an alkali solution to the copper-zinc removal liquid to remove Co, Ni, Al, and Sc, and then performing solid-liquid separation to obtain a deweighted liquid;

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

[0017] Furthermore, in step (a), the step of mixing the nickel cobalt hydroxide intermediate with the sulfuric acid solution and acid leaching specifically comprises: first mixing the nickel cobalt hydroxide intermediate and the water to prepare a slurry, and then adding a concentrated sulfuric acid solution thereto; preferably, the liquid-to-solid ratio of the nickel cobalt hydroxide intermediate and the water is 1.8 to 2.5 g / ml; preferably, the pH of the reaction system of the acid leaching and / or the pH of the reaction end point of the acid leaching = 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 leaching solution obtained after the acid leaching is ≤100 g / L.

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

[0022] Furthermore, in step (a), the flocculant is added and stirred for 10 to 30 minutes, and then allowed to stand for 30 to 60 minutes for the sedimentation.

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

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

[0025] Furthermore, in step (c), a concentrated sulfuric acid solution or a dilute sulfuric acid solution is used to adjust the pH of the precipitated liquid.

[0026] Furthermore, in step (c), the composite extractant containing P507 and C272 comprises a P507 extractant, a C272 extractant and a 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 extraction is 50% to 55%.

[0028] Furthermore, in step (c), the first extraction has a phase ratio O / A of 1.5 to 2:1.

[0029] Furthermore, in step (c), the loaded organic phase is stripped using a dilute sulfuric acid solution, wherein the molar concentration of the dilute sulfuric acid solution is 2.2 to 2.5 mol / L.

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

[0031] Furthermore, in step (d), the reducing agent comprises a hydrogen peroxide solution; preferably, the hydrogen peroxide solution is added for 3 to 4 hours; preferably, the heat-insulating reaction is continued for 1 hour after the hydrogen peroxide solution is added.

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

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

[0034] Furthermore, in step (d), the reducing leaching solution and the sodium carbonate solution are added simultaneously, and the adding time is controlled to be 3 to 4 hours; after the adding is completed, the temperature is kept at 2 to 5 hours to carry out the iron removal reaction.

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

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

[0037] Furthermore, in step (e), the pH at the end point of the reaction of the calcium and magnesium removal treatment is 5.0 to 6.0.

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

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

[0040] Furthermore, in step (f), the aluminum source includes at least one of anhydrous aluminum sulfate, aluminum sulfate 18hydrate and polyaluminum sulfate.

[0041] Furthermore, in step (f), the aluminum source is added according to a molar ratio of F element to Al element 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 time is 4 to 6 hours.

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

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

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

[0047] Furthermore, in step (g), the alkali solution includes at least one of a sodium hydroxide solution, a potassium hydroxide solution and an ammonia solution.

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

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

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

[0051] Furthermore, in step (h), the pH of the deweighted liquid is adjusted to 5.5-6.5.

[0052] Furthermore, in step (h), the flow rate of removing impurities using the modified resin is 1 to 3 BV / h.

[0053] The present invention further provides the use of the refined cobalt sulfate solution, refined nickel sulfate solution and refined manganese sulfate solution obtained by the method of preparing a sulfate solution for a precursor using a nickel cobalt hydroxide intermediate in the preparation of positive electrode precursors, positive electrode materials, positive electrode sheets and secondary batteries.

[0054] Compared with the prior art, the present invention has the following beneficial effects:

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

[0056] (2) The present invention provides a method for preparing a sulfate solution for a precursor using a nickel cobalt hydroxide intermediate. In the process of acid leaching the nickel cobalt hydroxide intermediate, a flocculant is added to promote the flocculation and agglomeration of manganese dioxide in the intermediate. The purpose of separating nickel cobalt from manganese dioxide (manganese slag) is achieved through a leaching acid dissolution-flocculation sedimentation process.

[0057] (3) The present invention provides a method for preparing a sulfate solution for a precursor using a nickel cobalt hydroxide intermediate. The mixed solution of nickel sulfate, cobalt and manganese obtained by acid dissolution is separated from most of the manganese ions under the action of a P507-C272 synergistic extractant. The use of the P507 extractant in this process can increase the load of the extraction process. At the same time, in this process, Ca ions are retained in the raffinate, so that the purpose of using sulfuric acid for stripping can be achieved without producing calcium sulfate slag.

[0058] (4) The method for preparing a precursor sulfate solution using a nickel cobalt hydroxide intermediate provided by the present invention uses P507-C272 synergistic extraction to increase the total concentration of the extractant, and uses P507 to appropriately improve the performance of the extractant, reduce the reaction temperature, speed up the phase separation rate, and improve the utilization rate of the extractant. Under the premise of not affecting the overall effect of the extraction process, the processing capacity (processing volume) of the extraction line is improved and the production cost is reduced.

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

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

[0061] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0062] Figure 1 A schematic flow chart of a method for preparing a sulfate solution for a precursor using a nickel cobalt hydroxide intermediate provided by the present invention. DETAILED DESCRIPTION

[0063] The technical scheme of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and specific embodiments, but it will be understood by those skilled in the art that the following described embodiments are part of embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention, and should not be considered as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention. If specific conditions are not specified in the embodiments, they are carried out according to normal conditions or conditions recommended by the manufacturer. If the manufacturer is not specified in the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0064] In the first aspect, the present invention provides a method for preparing a sulfate solution for a precursor using a nickel cobalt hydroxide intermediate, which mainly involves leaching and purifying the nickel cobalt hydroxide intermediate, wherein the sulfate solution for the precursor includes a cobalt sulfate solution, a nickel sulfate solution and a manganese sulfate solution. The present invention focuses on the recovery of manganese, improves the recovery rate of manganese, and has a low cost. Figure 1 As shown, the method specifically comprises the following steps:

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

[0066] In some specific embodiments, the main components of the nickel cobalt hydroxide intermediate (MHP for short) 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 content of the nickel cobalt hydroxide intermediate is 30% to 50%, the cobalt content is 2% to 6%, the manganese content is 3% to 10%, the magnesium content is 1% to 5%, the copper content is 0.1% to 0.5%, the calcium content is 0.1% to 0.6%, the zinc content is 0.3% to 1.5%, and the silicon content is 0.1% to 0.5%.

[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 thereto to perform 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 magnesium, iron, calcium, and magnesium impurity ions. The main components of the manganese slag include manganese dioxide.

[0070] (b) adjusting 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, and 6.5 or a range between any two of them, preferably 5.5 to 6.5; then separating the solid and the liquid to obtain a precipitated liquid and a precipitated residue.

[0071] (c) After adjusting the pH of the precipitated liquid to 2.0-3.5 (including but not limited to any point value 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 any range value between two of them), 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 stripped, and the stripped liquid obtained is a crude manganese sulfate solution. The raffinate is mixed with the P204 extractant for impurity removal to obtain a de-impurified liquid. The de-impurified liquid is subjected to a second extraction with the P507 extractant to obtain a refined cobalt sulfate solution and a nickel-magnesium raffinate. The nickel-magnesium raffinate is subjected to a third extraction with the C272 extractant to obtain a refined nickel sulfate solution.

[0072] In the prior art, in order to ensure that the use of C272 extractant has a good phase separation effect, the extraction process has many requirements. Generally, phase separation can only be achieved quickly under high temperature conditions. In addition, due to its high price, its concentration needs to be controlled at a low level to ensure that its loss rate is low. In addition, C272 is difficult to separate under high saponification rate conditions, so its saponification rate needs to be controlled to be ≤40%, not too high. The above conditions lead to low efficiency and high cost of the extraction process.

[0073] The present invention adopts P507-C272 synergistic extraction, which can increase the total concentration of the extractant, use P507 to appropriately improve the performance of the extractant, reduce the reaction temperature, accelerate the phase separation speed, and increase the saponification rate of the extraction process to 50% to 55%, thereby improving the utilization rate of the extractant. Under the premise of not affecting the overall effect of the extraction process, the processing capacity (processing volume) of the extraction line is improved and the production cost is reduced.

[0074] (d) mixing the manganese slag with a sulfuric acid solution and a reducing agent and performing reduction leaching to obtain a reduction leaching solution, wherein the main component of the reduction leaching solution is a manganese sulfate solution. The reduction leaching solution is mixed with a sodium carbonate solution and subjected to an iron removal reaction, followed by solid-liquid separation to obtain yellow sodium ferroaluminate slag and an iron-removed liquid. The main components of the slag are yellow sodium ferroaluminate and a small amount of hydroxide entrained.

[0075] (e) After the de-iron solution is mixed with the crude manganese sulfate solution, manganese fluoride is added thereto to perform a calcium and magnesium removal treatment. After the calcium and magnesium removal treatment reaction is completed, the solid and liquid are separated to obtain a de-fluorinated slag and a de-calcified and magnesium-removed solution. Among them, the main components of the de-fluorinated slag include calcium fluoride, magnesium fluoride and manganese fluoride, so the de-fluorinated slag can be recycled in the de-fluorination process until the calcium and magnesium content in the slag reaches a certain content.

[0076] (f) mixing the decalcified and magnesium-free liquid with an aluminum source and performing a defluorination treatment, and then performing solid-liquid separation to obtain a defluorinated liquid and crude aluminum fluoride.

[0077] (g) mixing the defluorinated liquid with sulfide and performing a copper-zinc removal treatment, and obtaining a copper-zinc removal liquid and copper-zinc sulfide solid after solid-liquid separation; adding alkali solution to the defluorinated liquid to perform a Co, Ni, Al, and Sc removal treatment (to precipitate Co, Ni, Al, and Sc impurities), and then performing solid-liquid separation to obtain a deweighted liquid and a filter residue. The filter residue can be sold as a by-product residue or used to recover valuable metals.

[0078] (h) After the pH of the deweighted liquid is adjusted to acidic, a modified resin is used to remove Si, F, and P ions, and the remaining trace amounts of Si, F, and P ions in the solution are removed to obtain a refined manganese sulfate solution.

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

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

[0081] Specifically, the present invention adds a flocculant during the acid leaching of nickel cobalt hydroxide intermediates, which can promote the flocculation and agglomeration of manganese dioxide in the intermediates, and achieves the purpose of separating nickel cobalt from manganese dioxide (manganese slag) through the leaching acid dissolution-flocculation sedimentation process. The nickel sulfate, cobalt, and manganese mixed solution obtained by acid dissolution is separated by the action of the P507-C272 synergistic extractant, and the use of the P507 extractant in this process can increase the load of the extraction process. At the same time, the Ca ions are left in the raffinate during this process, and the purpose of using sulfuric acid back extraction without producing calcium sulfate slag can be achieved. After the crude manganese sulfate solution is mixed with the iron removal liquid, manganese fluoride is used to remove calcium and magnesium, which can effectively reduce the calcium and magnesium content. After that, aluminum fluoride is generated by adding an aluminum source, and the purpose of defluorination can be achieved. At the same time, a crude aluminum fluoride byproduct is obtained. The P, F, and Si ions in the solution can be removed by adsorbing the deweighting liquid using a modified resin.

[0082] The present invention uses a flocculant to separate most of manganese from cobalt and nickel in the initial reaction, centrally treats manganese slag, and removes impurities from manganese leaching solution by chemical method. The operation is simple and easy to control, while improving the direct metal recovery rate and reducing the production cost, so as to obtain a manganese sulfate solution that meets the requirements of precursor production.

[0083] In addition, the present invention adopts P507-C272 synergistic extraction, which can increase the total concentration of the extractant, reduce the reaction temperature, accelerate the phase separation speed, and increase the saponification rate of the extraction process to 50% to 55%, thereby improving the utilization rate of the extractant. Under the premise of not affecting the overall effect of the extraction process, the processing capacity (processing volume) of the extraction line is improved and the production cost is reduced.

[0084] The products prepared by the present invention mainly include cobalt sulfate solution, nickel sulfate solution, and manganese sulfate solution, each of which has a low impurity content and meets the production and use requirements of ternary precursors. In addition, byproducts such as yellow sodium iron alum slag and crude aluminum fluoride are also produced, which can improve economic benefits.

[0085] In addition, in the present invention, manganese metal is recovered in a centralized manner, which has a short process flow and is simple to operate compared to a full leaching and then gradual separation and recovery method.

[0086] In some specific embodiments, in step (a), the step of mixing the nickel cobalt hydroxide intermediate with the sulfuric acid solution and acid leaching specifically comprises: firstly mixing the nickel cobalt hydroxide intermediate with the water to prepare a slurry, and then adding the concentrated sulfuric acid solution thereto. This is conducive to subsequent solid-liquid separation.

[0087] Preferably, the liquid-to-solid ratio of the nickel cobalt hydroxide intermediate and the water is 1.8 to 2.5 g / ml, including but not limited to any point value 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 value between any two of them. By controlling the liquid-to-solid ratio of the nickel cobalt hydroxide intermediate and water, the rate of subsequent solid-liquid separation can be regulated. The use of this solid-to-liquid ratio is conducive to 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 any one of 0.5, 0.6, 0.7, 0.8, 0.9, 1.0 or any range between two values. And / or, the pH of the acid leaching reaction endpoint is 0.5-1.0, including but not limited to any one of 0.5, 0.6, 0.7, 0.8, 0.9, 1.0 or any range between two values.

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

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

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

[0092] In some specific embodiments, in step (a), the flocculant includes at least one of an alkyl quaternary ammonium salt cationic surfactant solution, an ester quaternary ammonium salt cationic surfactant solution and a polymeric cationic surfactant solution. Adding a flocculant is beneficial to further improve the rate of subsequent solid-liquid separation. Studies have found that the mass concentration of nickel in the leachate is 98g / L. When no flocculant is added, the filtration rate is 2.89ml / min; when 2mg / L of flocculant is added, the filtration rate is 7.67ml / min; when 4mg / L of flocculant is added, the filtration rate is 18.00ml / min; when 6mg / L of flocculant is added, the filtration rate is 24.50ml / min; when 8mg / L of flocculant is added, the filtration rate is 18.20ml / min; when 10mg / L of flocculant is added, the filtration rate is 20.65ml / min.

[0093] Preferably, the polymeric cationic surfactant solution comprises 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 point value of 0.5‰, 0.6‰, 0.8‰, 1‰, 1.2‰, 1.3‰, 1.5‰ or a range between any two of them.

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

[0096] In some specific embodiments, in step (a), after adding the flocculant, stirring is carried out for 10 to 30 minutes (including but not limited to any one of 10 minutes, 15 minutes, 20 minutes, 25 minutes, and 30 minutes, or a range between any two of them), and then standing for 30 to 60 minutes (including but not limited to any one of 30 minutes, 35 minutes, 40 minutes, 45 minutes, 50 minutes, and 60 minutes, or a range between any two of them) to carry out the sedimentation.

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

[0098] It is understandable that the first adjustment may also be performed using an alkali solution such as a sodium carbonate solution. In some specific embodiments, in step (b), after obtaining the precipitated residue, the precipitated residue is mixed with a dilute sulfuric acid solution or a concentrated sulfuric acid solution and leached to obtain a leachate, and 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 sulfate nickel manganese mixed solution in step (b).

[0099] In some specific embodiments, in step (c), a concentrated sulfuric acid solution or a dilute sulfuric acid solution is used to adjust the pH of the precipitated liquid; preferably a dilute sulfuric acid solution is used to facilitate pH control.

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

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

[0102] Under the condition that the overall concentration of the extractant is about 25%, the present invention increases the saponification rate from 40% to about 55%, and the utilization rate of the extractant can be increased to the original 137.5%. At the same time, according to the price difference between P507 and C272, the cost of the extractant can be saved.

[0103] In some specific embodiments, in step (c), the first extraction has a phase ratio O / A=1.5-2:1, including but not limited to any point value of 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1, 2:1 or a range value between any two of them. This extraction phase ratio is beneficial for extracting and separating Mn. Wherein, O / A represents the volume ratio of the organic phase to the aqueous phase.

[0104] In some specific embodiments, in step (c), the loaded organic phase is stripped with 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 of them.

[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 comprises a hydrogen peroxide solution.

[0107] Preferably, the hydrogen peroxide solution is added for 3 to 4 hours, such as 3.5 hours.

[0108] Preferably, the hydrogen peroxide solution is added and the reaction is continued for 1 hour.

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

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

[0111] It is understood that the amount of sodium carbonate added can be adjusted according to the pH value at the end point of iron removal.

[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 is added for every 1 g of Mn element.

[0113] In some specific embodiments, 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, 100°C or a range between any two of them.

[0114] In some specific embodiments, in step (d), the reducing leaching solution and the sodium carbonate solution are added simultaneously, and the adding time is controlled to be 3 to 4 hours, for example, 3.5 hours. After the adding is completed, the temperature is kept at 2 to 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 4.0-5.0, including but not limited to any point value of 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.8, 5.0 or a range value between any two of them; preferably 4.0-4.5.

[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 ions and magnesium ions; including but not limited to 80 times, 85 times, 90 times, 95 times, 100 times, 110 times, 120 times, any one of the point values ​​or the range value between any two of them.

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

[0118] In some specific embodiments, in step (e), the temperature of the 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, 95°C or any range between two thereof. Preferably, it is 85-90°C.

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

[0120] In some specific implementations, in step (e), in the calcium- and magnesium-removed liquid, the mass concentration of Mg element is ≤0.005 g / L, and the mass concentration of Ca element 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 18hydrate and polyaluminum sulfate.

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

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

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

[0125] In some specific implementations, in step (f), the mass concentration of F element in the defluorinated liquid is 0.3-0.4 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 hydrogen sulfide.

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

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

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

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

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

[0132] In some specific embodiments, in step (g), the reaction time of the treatment for 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 liquid.

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

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

[0136] In some specific embodiments, in step (h), the flow rate of removing impurities using the modified resin is 1 to 3 BV / h, including but not limited to any point value of 1 BV / h, 1.5 BV / h, 2 BV / h, 2.5 BV / h, 3 BV / h or a range value between any two of them.

[0137] In some specific embodiments, the Si, F, and P removal treatment 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 independently ≤0.002 g / L.

[0139] In a second aspect, the present invention provides the use of the refined cobalt sulfate solution, refined nickel sulfate solution and refined manganese sulfate solution obtained by the method of preparing a sulfate solution for a precursor using a 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 prepared by the above method can be used to synthesize nickel-cobalt-manganese precursors or other precursor materials, and then the positive electrode materials can be obtained after sintering, and then the positive electrode sheets and secondary batteries can be obtained after assembly.

[0141] The refined cobalt sulfate solution, refined nickel sulfate solution and refined manganese sulfate solution prepared by the above method are used to prepare positive electrode precursors, positive electrode materials, positive electrode sheets and secondary batteries, with lower costs.

[0142] The embodiments of the present invention will be described in detail below in conjunction with the examples, but it will be appreciated by those skilled in the art that the following examples are only used to illustrate the present invention and should not be considered as limiting the scope of the present invention. If no specific conditions are specified in the examples, the conditions are carried out according to normal conditions or the conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be obtained commercially.

[0143] Example 1

[0144] The method provided in this embodiment for preparing a sulfate solution (cobalt sulfate solution, nickel sulfate solution and manganese sulfate solution) for a precursor using a nickel cobalt hydroxide intermediate comprises the following steps:

[0145] (1) Obtain a 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 ratio of liquid-solid ratio of nickel cobalt hydroxide intermediate and pure water L / S=2g / ml, pure water and nickel cobalt hydroxide intermediate are mixed and slurried, and then concentrated sulfuric acid solution is added thereto, and the reaction is kept at 83°C for 5h. During the reaction, the pH of the system is controlled to be 0.8, and the pH of the acid leaching reaction end point is 0.8. The mass concentration of nickel element in the leaching solution obtained after acid leaching is 80.5g / L. According to the addition amount of 8mg / L (that is, 8mg of polymeric cationic surfactant solution is added to each L of leaching solution), cationic polyacrylamide solution (with a mass fraction of 1‰) is added to the leaching solution, stirred for 20min, and then allowed to stand for 40min for sedimentation, and then filtered to obtain a cobalt sulfate nickel manganese mixed solution and manganese slag. The contents of cobalt, nickel, copper, manganese, silicon and scandium elements in the cobalt sulfate nickel manganese mixed solution and manganese slag, as well as the leaching rates of cobalt, nickel, copper, manganese, silicon and scandium elements are shown in Table 2.

[0149] Table 2 Main composition and leaching rate of each element of 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 sodium carbonate solution with a mass fraction of 13%, the pH of the cobalt-nickel-manganese sulfate mixed solution obtained in step (1) is adjusted to 6, and then filtered to obtain a precipitated liquid and a precipitated residue. The precipitated residue is mixed with a dilute sulfuric acid solution and leached to obtain a leachate, and then the leachate is mixed with the nickel-cobalt hydroxide intermediate to obtain a slurry of the nickel-cobalt hydroxide intermediate, which is used to adjust the pH of the cobalt-nickel-manganese sulfate mixed solution in step (2) in other embodiments.

[0152] (3) The precipitated liquid obtained in step (2) is adjusted to pH=2.8 with a 2.3 mol / L dilute sulfuric acid solution, and then enters into a P507-C272 mixed extractant to extract Mn, thereby obtaining a raffinate and a loaded organic phase, wherein the P507-C272 mixed extractant is composed of 12% P507, 13% C272 and 75% sulfonated kerosene in terms of mass percentage. The saponification rate is controlled to be 55%, and nickel soap is converted. O / A is controlled to be 1.8:1 for extraction, and Mn is extracted and separated. Thereafter, the loaded organic phase is stripped with a dilute sulfuric acid solution having a molar concentration of 2.3 mol / L, and the stripped liquid obtained is a crude manganese sulfate solution. The raffinate is subjected to a P204 extractant for impurity removal to obtain a de-impurity liquid. The P507 extractant is then used to recover cobalt (i.e., the second extraction) to obtain a refined cobalt sulfate solution and a nickel-magnesium raffinate. Finally, the nickel-magnesium raffinate is subjected to nickel-magnesium separation (i.e., the third extraction) using C272 extractant to obtain a refined nickel sulfate solution, wherein the yield of metallic nickel is 99.36%, and the yield of metallic cobalt is 99.74%.

[0153] (4) The manganese slag (mainly composed of manganese dioxide) obtained in step (1) was subjected to reduction leaching at 85° C. using concentrated sulfuric acid solution and hydrogen peroxide (mass fraction of 27%), wherein the addition time of hydrogen peroxide solution was 4 hours, and the addition amount of hydrogen peroxide solution was 10 mL of 27% hydrogen peroxide solution per 1 g of manganese element, and the reaction was continued for 1 hour after the addition of hydrogen peroxide solution, to obtain reduction leaching solution and leaching slag. The main components of manganese slag, the main components of reduction leaching solution, the main components of leaching slag and the leaching rate of each element are shown in Table 3.

[0154] Table 3 Main components of manganese slag, reduction leaching solution, leaching slag, and leaching rate 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 Reduction leaching solution (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 reduction leaching solution and sodium carbonate solution (mass concentration is 250g / L, and the amount added is adjusted according to the pH value of the end point of the iron removal reaction) are mixed in parallel (i.e., added simultaneously) to carry out the iron removal reaction (convection iron removal process), wherein the time for controlling the parallel addition of the feed liquid is 4h, the temperature of the iron removal reaction is 95°C, and the temperature is kept warm for 3h after the addition is completed. Then filter to obtain yellow sodium iron alum slag and iron removal liquid. Among them, the main composition of the reduction leaching solution, the main composition of the iron removal liquid and its pH, and the precipitation rate of each element are shown in Table 4.

[0157] Table 4 Main composition of reduction leaching solution, main composition of iron removal solution and its pH, precipitation rate

[0158] element Co Ni Cu Fe Mn Al Si Sc pH Reduction leachate 4.33 5.22 0.24 1.83 123.07 1.31 0.24 0.03 0.88 Liquid after iron removal (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 removal solution obtained in step (4) is mixed with the crude manganese sulfate solution obtained in step (3) and then enters the calcium and magnesium removal process together (the mixed solution is referred to as the calcium and magnesium removal pre-liquid), and manganese fluoride solid is added thereto, the amount of manganese fluoride added is 100 times the theoretical total mass of the reaction with calcium ions and magnesium ions, the reaction end point pH = 5.5, the system temperature during the reaction is 88°C, and the reaction time is 7h. Then filter to obtain the defluorination slag and the calcium and magnesium removal solution. Among them, the main components and pH of the calcium and magnesium removal pre-liquid, and the main components and pH of the calcium and magnesium removal solution are shown in Table 5.

[0160] Table 5 Main composition and pH value of pre-liquid and post-liquid for calcium and magnesium removal

[0161] element Co Ni Cu Fe Ca Mg Mn Zn F pH Pre-liquid for calcium and magnesium removal (g / L) 4.69 5.54 0.13 0.010 0.19 0.13 133.68 0.28 0.005 4.01 Liquid 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) According to the molar ratio of F element to Al element of 4.5:1, anhydrous aluminum sulfate crystals were added to the decalcified and magnesium-free solution obtained in step (5) to perform defluorination treatment. The defluorination treatment temperature was 82°C and the reaction time was 5 hours. Afterwards, the defluorinated solution and crude aluminum fluoride were obtained by filtration. The main components and pH of the decalcified and magnesium-free solution and the main components and pH of the defluorinated solution are shown in Table 6.

[0163] Table 6 Main composition and pH of the solution after calcium and magnesium removal and the solution after fluorine removal

[0164] element F Al Co Ni Mn pH Liquid after calcium and magnesium removal (g / L) 9.87 0.0025 4.32 5.34 129.96 5.52 Fluoride-free liquid (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) to perform copper and zinc removal treatment (room temperature, 25° C.), wherein the amount of manganese sulfide added is 13 times the theoretical total mass of manganese sulfide required to react with copper ions and zinc ions, and the copper and zinc removal treatment time is 2 hours. After filtering, the copper and zinc removal liquid is obtained. Add a 10% sodium hydroxide solution by mass fraction to the copper and zinc removal liquid until the pH of the mixed system is 8.1, remove Co, Ni, Al, and Sc, stir the reaction for 2 hours, and separate the solid and liquid to obtain a deweighted liquid. Among them, the main components and pH values ​​of the defluorinated liquid, the main components and pH values ​​of the copper and zinc removal liquid, and the main components and pH values ​​of the deweighted liquid are shown in Table 7.

[0166] Table 7 Main composition and pH value of the defluorinated solution, copper and zinc deoxidized solution, and weight deoxidized solution

[0167] element Cu Zn Co Ni Al Sc pH Fluoride-free liquid (g / L) 0.05 0.23 3.52 4.43 0.29 0.095 6.07 Liquid after copper and zinc removal (g / L) 0.0005 0.0044 0.66 1.32 0.031 0.0016 6.5 Liquid after deweighting (g / L) 0.0003 0.001 0.0005 0.002 0.0005 0.0005 8.1

[0168] (8) After adjusting the pH of the de-weighted liquid obtained in step (7) to 6.0 with a 1 mol / L dilute sulfuric acid solution, a zirconium ion modified resin (LSC-860) was used to remove Si, F, and P, wherein the resin impurity removal flow rate was 2.0 BV / h, to obtain a refined manganese sulfate solution. The de-weighted liquid and its pH, the main composition of the refined manganese sulfate solution and its pH value 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 composition and pH value of the deweighted liquid and refined manganese sulfate solution

[0170] element Cu Zn Co Ni Liquid after deweighting (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 provided in this embodiment for preparing a sulfate solution (cobalt sulfate solution, nickel sulfate solution and manganese sulfate solution) for a precursor using a nickel cobalt hydroxide intermediate comprises the following steps, and the flow chart thereof is shown in 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 ratio of liquid-solid ratio of nickel cobalt hydroxide intermediate and pure water L / S = 1.8g / ml, pure water and nickel cobalt hydroxide intermediate are mixed and slurried, and then concentrated sulfuric acid solution is added thereto, and the reaction is kept at 85°C for 3h. During the reaction, the pH of the system is controlled to be 1.0, and the pH of the acid leaching reaction end point is 1.0. The mass concentration of nickel element in the leaching solution obtained after acid leaching is 96.14g / L. According to the addition amount of 10mg / L (that is, 10mg of polymeric cationic surfactant solution is added to each L of leaching solution), cationic polyacrylamide solution (with a mass fraction of 0.5‰) is added to the leaching solution, stirred for 30min, and then allowed to stand for 30min for sedimentation, and then filtered to obtain a cobalt sulfate nickel manganese mixed solution and manganese slag. The contents of cobalt, nickel, copper, manganese, silicon and scandium elements in the cobalt sulfate nickel manganese mixed solution and manganese slag, as well as the leaching rates of cobalt, nickel, copper, manganese, silicon and scandium elements 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 the nickel cobalt hydroxide intermediate obtained in step (2) of Example 1, the pH of the cobalt nickel manganese sulfate mixed solution obtained in step (1) is adjusted to 5.5, and then filtered to obtain a precipitated liquid and a precipitated residue. The precipitated residue is mixed with a dilute sulfuric acid solution and leached to obtain a leachate, and then the leachate is mixed with the nickel cobalt hydroxide intermediate to obtain a slurry of the nickel cobalt hydroxide intermediate, which can be reused.

[0182] (3) The precipitated liquid obtained in step (2) is adjusted to pH=2.5 with a 2.2 mol / L dilute sulfuric acid solution, and then enters into a P507-C272 mixed extractant to extract Mn, thereby obtaining a raffinate and a loaded organic phase, wherein the P507-C272 mixed extractant is composed of 10% P507, 10% C272 and 80% sulfonated kerosene in terms of mass percentage. The saponification rate is controlled to be 50%, and nickel soap is converted. O / A is controlled to be 1.5:1 for extraction, and Mn is extracted and separated. Thereafter, the loaded organic phase is stripped with a dilute sulfuric acid solution having a molar concentration of 2.2 mol / L, and the stripped liquid obtained is a crude manganese sulfate solution. The raffinate is subjected to a P204 extractant for impurity removal to obtain a de-impurity liquid. The P507 extractant is then used to recover cobalt (i.e., the second extraction) to obtain a refined cobalt sulfate solution and a nickel-magnesium raffinate. Finally, the nickel-magnesium raffinate is subjected to nickel-magnesium separation (i.e., the third extraction) using C272 extractant to obtain a refined nickel sulfate solution, wherein the yield of metallic nickel is 98.62%, and the yield of metallic cobalt is 98.49%.

[0183] (4) The manganese slag (mainly composed of manganese dioxide) obtained in step (1) was subjected to reduction leaching at 80° C. using concentrated sulfuric acid solution and hydrogen peroxide (30% by mass), wherein the hydrogen peroxide solution was added for 3 h, and the amount of hydrogen peroxide solution added was 8 mL of 30% by mass hydrogen peroxide solution per 1 g of manganese element. After the hydrogen peroxide solution was added, the reaction was continued for 1 h to obtain a reduction leaching solution and leaching slag. The main components of the manganese slag, the main components of the reduction leaching solution, the main components of the leaching slag, and the leaching rates of each element are shown in Table 12.

[0184] Table 12 Main components of manganese slag, reduction leaching solution, leaching slag, and leaching rate 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 Reduction leaching solution (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 reduction leaching solution and sodium carbonate solution (mass concentration is 250g / L, and the amount added is adjusted according to the pH value of the end point of the iron removal reaction) are mixed in parallel (i.e., added simultaneously) to carry out the iron removal reaction (convection iron removal process), wherein the time for the parallel addition of the feed liquid is controlled to be 3h, the temperature of the iron removal reaction is 100°C, and the temperature is kept warm for 2h after the addition is completed. Then filter to obtain yellow sodium iron alum slag and iron removal liquid. Among them, the main composition of the reduction leaching solution, the main composition of the iron removal liquid and its pH, and the precipitation rate of each element are shown in Table 13.

[0187] Table 13 Main composition of reduction leaching solution, main composition of iron removal solution and its pH and precipitation rate

[0188] element Co Ni Cu Fe Mn Al Si Sc pH Reduction leachate 2.78 10.19 0.35 1.91 113.07 1.36 0.23 0.06 0.76 Liquid after iron removal (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 removal solution obtained in step (4) is mixed with the crude manganese sulfate solution obtained in step (3) and then enters the calcium and magnesium removal process together (the mixed solution is referred to as the calcium and magnesium removal pre-liquid), and manganese fluoride solid is added thereto, the amount of manganese fluoride added is 110 times the theoretical total mass of the reaction with calcium ions and magnesium ions, the reaction end point pH = 5.0, the system temperature during the reaction is 95°C, and the reaction time is 6h. Then filter to obtain the defluorination slag and the calcium and magnesium removal solution. Among them, the main components and pH of the calcium and magnesium removal pre-liquid, and the main components and pH of the calcium and magnesium removal solution are shown in Table 14.

[0190] Table 14 Main composition and pH value of pre-liquid and post-liquid for calcium and magnesium removal

[0191] element Co Ni Cu Fe Ca Mg Mn Zn F pH Pre-liquid for calcium and magnesium removal (g / L) 2.77 8.07 0.12 0.003 0.15 0.12 116.69 0.20 0.005 4.32 Liquid 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) According to the molar ratio of F element to Al element of 3.5:1, polyaluminum sulfate was added to the decalcified and magnesium-free solution obtained in step (5) to carry out defluorination treatment. The defluorination treatment temperature was 75°C and the reaction time was 4 hours. After that, the solution was filtered to obtain defluorinated solution and crude aluminum fluoride. The main components and pH of the decalcified and magnesium-free solution and the main components and pH of the defluorinated solution are shown in Table 15.

[0193] Table 15 Main composition and pH of the solution after calcium and magnesium removal and the solution after fluorine removal

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

[0195] (7) Sodium sulfide is added to the defluorinated liquid obtained in step (6) to perform a copper and zinc removal treatment (room temperature, 25° C.), wherein the amount of sodium sulfide added is 15 times the theoretical total mass of manganese sulfide required to react with copper ions and zinc ions, and the copper and zinc removal treatment time is 2 hours. After filtration, a copper and zinc removal liquid is obtained. Then, a sodium hydroxide solution with a mass fraction of 10% is added to the copper and zinc removal liquid until the pH of the mixed system is 7.5, and a Co, Ni, Al, and Sc removal treatment is performed. After stirring the reaction for 4 hours, the solid and liquid are separated to obtain a deweighted liquid. Among them, the main components and pH values ​​of the defluorinated liquid, the main components and pH values ​​of the copper and zinc removal liquid, and the main components and pH values ​​of the deweighted liquid are shown in Table 16.

[0196] Table 16 Main composition and pH value of the defluorinated liquid, copper and zinc deoxidized liquid, and weight deoxidized liquid

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

[0198] (8) After adjusting the pH of the de-weighted liquid obtained in step (7) to 6.5 with a 1.5 mol / L dilute sulfuric acid solution, a modified resin of Haipu HP4800 was used to remove Si, F, and P, wherein the flow rate of the resin impurity removal was 1.5 BV / h, to obtain a refined manganese sulfate solution. The de-weighted liquid and its pH, the main composition of the refined manganese sulfate solution and its pH value 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 composition and pH value of the deweighted liquid and refined manganese sulfate solution

[0200] element Si F P pH Liquid after deweighting (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 provided in this embodiment for preparing a sulfate solution (cobalt sulfate solution, nickel sulfate solution and manganese sulfate solution) for a precursor using a nickel cobalt hydroxide intermediate comprises 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 ratio of liquid-solid ratio of nickel cobalt hydroxide intermediate and pure water L / S = 2.5g / ml, pure water and nickel cobalt hydroxide intermediate are mixed and slurried, and then concentrated sulfuric acid solution is added thereto, and the reaction is kept at 80°C for 6h. During the reaction, the pH of the system is controlled to be 0.5, and the pH at the end of the acid leaching reaction is 0.5. The mass concentration of nickel element in the leaching solution obtained after acid leaching is 87.3g / L. According to the addition amount of 5mg / L (that is, 5mg of polymeric cationic surfactant solution is added to each L of leaching solution), cationic polyacrylamide solution (with a mass fraction of 1.5‰) is added to the leaching solution, stirred for 10min, and then allowed to stand for 60min for sedimentation, and then filtered to obtain a cobalt sulfate nickel manganese mixed solution and manganese slag. The contents of cobalt, nickel, copper, manganese, silicon and scandium elements in the cobalt sulfate nickel manganese mixed solution and manganese slag, as well as the leaching rates of cobalt, nickel, copper, manganese, silicon and scandium elements 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 the nickel cobalt hydroxide intermediate obtained in step (2) of Example 1, the pH of the cobalt nickel manganese sulfate mixed solution obtained in step (1) is adjusted to 6.5, and then filtered to obtain a precipitated liquid and a precipitated residue. The precipitated residue is mixed with a dilute sulfuric acid solution and leached to obtain a leachate, and then the leachate is mixed with the nickel cobalt hydroxide intermediate to obtain a slurry of the nickel cobalt hydroxide intermediate, which can be reused.

[0212] (3) The precipitated liquid obtained in step (2) is adjusted to pH=3.0 with a 2.5 mol / L dilute sulfuric acid solution, and then enters into a P507-C272 mixed extractant to extract Mn, thereby obtaining a raffinate and a loaded organic phase, wherein the P507-C272 mixed extractant is composed of 15% P507, 15% C272 and 70% sulfonated kerosene in terms of mass percentage. The saponification rate is controlled to be 53%, and nickel soap is converted. O / A is controlled to be 2:1 for extraction, and Mn is extracted and separated. Thereafter, the loaded organic phase is stripped with a dilute sulfuric acid solution having a molar concentration of 2.5 mol / L, and the stripped liquid obtained is a crude manganese sulfate solution. The raffinate is subjected to a P204 extractant for impurity removal to obtain a de-impurity liquid. The P507 extractant is then used to recover cobalt (i.e., the second extraction) to obtain a refined cobalt sulfate solution and a nickel-magnesium raffinate. Finally, the nickel-magnesium raffinate is subjected to nickel-magnesium separation (i.e., the third extraction) using C272 extractant to obtain a refined nickel sulfate solution, wherein the yield of metallic nickel is 98.45%, and the yield of metallic cobalt is 98.78%.

[0213] (4) The manganese slag (mainly composed of manganese dioxide) obtained in step (1) was subjected to reduction leaching at 75° C. using concentrated sulfuric acid solution and hydrogen peroxide (30% by mass), wherein the addition time of hydrogen peroxide solution was 3 h, and the addition amount of hydrogen peroxide solution was 9 mL of 30% by mass hydrogen peroxide solution per 1 g of manganese element. After the addition of hydrogen peroxide solution, the reaction was continued for 1 h to obtain reduction leaching solution and leaching slag. The main components of manganese slag, the main components of reduction leaching solution, the main components of leaching slag and the leaching rate of each element are shown in Table 21.

[0214] Table 21 Main components of manganese slag, reduction leaching solution, leaching slag, and leaching rate 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 Reduction leaching solution (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 reduction leaching solution and sodium carbonate solution (mass concentration is 230g / L, and the amount added is adjusted according to the pH value of the end point of the iron removal reaction) are mixed in parallel (i.e., added simultaneously) to carry out the iron removal reaction (convection iron removal process), wherein the time for the parallel addition of the feed liquid is controlled to be 3.5h, the temperature of the iron removal reaction is 98°C, and the temperature is kept warm for 5h after the addition is completed. Then filter to obtain yellow sodium iron alum slag and iron removal liquid. Among them, the main composition of the reduction leaching solution, the main composition of the iron removal liquid and its pH, and the precipitation rate of each element are shown in Table 22.

[0217] Table 22 Main components of reduction leaching solution, main components of iron removal solution and their pH and precipitation rate

[0218] element Co Ni Cu Fe Mn Al Si Sc pH Reduction leachate 2.92 4.82 1.16 1.67 119.85 1.41 0.12 0.03 0.91 Liquid after iron removal (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 de-iron solution obtained in step (4) is mixed with the crude manganese sulfate solution obtained in step (3) and then enters the calcium and magnesium removal process together (the mixed solution is referred to as the pre-calculation and magnesium removal solution), and manganese fluoride solid is added thereto. The amount of manganese fluoride added is 80 times the theoretical total mass of the reaction with calcium ions and magnesium ions. The pH at the reaction end point is 6.0. The system temperature during the reaction is 80°C and the reaction time is 8 hours. Then filter to obtain de-fluorination slag and the post-calculation and magnesium removal solution. The main components and pH of the pre-calculation and magnesium removal solution and the main components and pH of the post-calculation and magnesium removal solution are shown in Table 23.

[0220] Table 23 Main composition and pH value of pre-liquid and post-liquid for calcium and magnesium removal

[0221] element Co Ni Cu Fe Ca Mg Mn Zn F pH Pre-liquid for calcium and magnesium removal (g / L) 2.78 3.63 0.37 0.001 0.05 0.07 120.16 0.23 0.004 4.58 Liquid 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) According to the molar ratio of F element to Al element of 5.0:1, anhydrous aluminum sulfate crystals were added to the decalcified and magnesium-free solution obtained in step (5) to carry out defluorination treatment. The defluorination treatment temperature was 90°C and the reaction time was 6 hours. After that, the solution was filtered to obtain defluorinated solution and crude aluminum fluoride. The main components and pH of the decalcified and magnesium-free solution and the main components and pH of the defluorinated solution are shown in Table 24.

[0223] Table 24 Main composition and pH of the solution after calcium and magnesium removal and the solution after fluorine removal

[0224] element F Al Co Ni Mn pH Liquid after calcium and magnesium removal (g / L) 11.82 0.0055 2.55 3.13 113.56 5.79 Fluoride-free liquid (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 a copper and zinc removal treatment (room temperature, 25° C.), wherein the amount of ammonium sulfide added is 12 times the theoretical total mass of manganese sulfide required to react with copper ions and zinc ions, and the copper and zinc removal treatment time is 2 hours. After filtration, a copper and zinc removal liquid is obtained. Then, a sodium hydroxide solution with a mass fraction of 10% is added to the copper and zinc removal liquid until the pH of the mixed system is 9.0, and a Co, Ni, Al, and Sc removal treatment is performed. After stirring the reaction for 2 hours, the solid and liquid are separated to obtain a deweighted liquid. Among them, the main components and pH values ​​of the defluorinated liquid, the main components and pH values ​​of the copper and zinc removal liquid, and the main components and pH values ​​of the deweighted liquid are shown in Table 25.

[0226] Table 25 Main composition and pH value of the defluorinated liquid, copper and zinc deoxidized liquid, and weight deoxidized liquid

[0227] element Cu Zn Co Ni Al Sc pH Fluoride-free liquid (g / L) 0.15 0.13 1.93 2.94 0.16 0.095 5.99 Liquid after copper and zinc removal (g / L) 0.0005 0.0015 0.49 0.67 0.005 0.001 6.71 Liquid after deweighting (g / L) 0.0001 0.0008 0.0005 0.0005 0.0001 0.0005 9.0

[0228] (8) After adjusting the pH of the de-weighted solution obtained in step (7) to 5.5 with a 1.1 mol / L dilute sulfuric acid solution, a zirconium ion modified resin (LSC-860) was used to remove Si, F, and P, wherein the resin impurity removal flow rate was 2.5 BV / h, to obtain a refined manganese sulfate solution. The de-weighted solution and its pH, the main composition of the refined manganese sulfate solution and its pH value 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 composition and pH value of the deweighted liquid and refined manganese sulfate solution

[0230] element Si F P pH Liquid after deweighting (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 provided in this embodiment for preparing a sulfate solution (cobalt sulfate solution, nickel sulfate solution and manganese sulfate solution) for a precursor using a nickel cobalt hydroxide intermediate is basically the same as that in Example 1, except that: in step (3), the P507-C272 mixed extractant is composed of 12% P507, 15% C272 and 73% sulfonated kerosene in terms of mass percentage.

[0235] Example 5

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

[0237] Example 6

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

[0239] Comparative Example 1

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

[0241] Comparative Example 2

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

[0243] Comparative Example 3

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

[0245] Among them, C272: 150,000 yuan / ton, P507: 35,000 yuan / ton. During the extraction process, when C272 is used alone, the high concentration is not conducive to phase separation and the clarification time is long. The higher the concentration of C272 in the mixed extractant, the more unfavorable it is for phase separation. Therefore, when C272 is used alone, it needs to be used at a low concentration. However, a low concentration of C272 will lead to a decrease in processing capacity. The present invention adopts a mixed extractant and can increase the overall concentration of the organic phase by adding a portion of P507, thereby ensuring a low extraction rate of Ca while improving the processing capacity, reducing production costs and improving economic benefits.

[0246] The main difference between Comparative Example 1, Comparative Example 2 and Comparative Example 3 is the different proportion of organic content. The higher the C272 content, the lower the Ca content in the manganese solution, but the cost is too high. The Ca content is too high when only P507 is used for extraction. At the same time, calcium sulfate slag will be formed in the extraction tank when sulfuric acid is used for stripping, causing blockage of the equipment pipeline.

[0247] Comparative Example 4

[0248] The method provided in this comparative example for preparing a precursor sulfate solution (cobalt sulfate solution, nickel sulfate solution and manganese sulfate solution) using a nickel cobalt hydroxide intermediate is basically the same as that in Example 1, except that in step (1), no cationic polyacrylamide solution is added.

[0249] In Example 1, flocculants are added before filtration to increase the flocculation effect of the slag in the solution and improve the filtration speed. The filtration speed of the slurry after leaching the same volume is 20 times that of the comparative example 4. The comparative example does not add flocculants. Since the MnO2 particles in the slag are too fine, the phenomenon of filtering and being unable to filter is caused, which increases the pressure and sealing requirements of the filtration equipment. It is not conducive to production and use. Due to various restrictions, the process of acid leaching to separate nickel, cobalt and manganese slag is also difficult to operate. It is not conducive to process optimization.

[0250] Comparative Example 5

[0251] The method provided in this comparative example for preparing a sulfate solution (cobalt sulfate solution, nickel sulfate solution and manganese sulfate solution) for a precursor using a nickel cobalt hydroxide intermediate 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 does not use resin to remove Si, F, and P. The impurity content of Si, F, and P in the obtained manganese solution is high, and the impurity content is unqualified. It cannot be directly used for precursor production. Si and P may be introduced into the precursor product, resulting in unqualified products. The high F content may corrode and damage the equipment, resulting in increased maintenance costs for production equipment. The Si, F, and P contents and pH values ​​in the refined manganese sulfate solutions obtained in Example 1 and this comparative example 5 are shown in Table 28.

[0253] Table 28 Si, F, P content and pH in refined manganese sulfate solution of 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 appreciated that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Those skilled in the art should understand that the technical solutions described in the above embodiments may be modified, or some or all of the technical features thereof may be replaced by equivalents without departing from the spirit and scope of the present invention. However, these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention. Therefore, this means that all such replacements and modifications 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: The steps include: (a) mixing the nickel cobalt hydroxide intermediate with a sulfuric acid solution and acid leaching, then adding a flocculant thereto for sedimentation, and then separating the solid from the liquid to obtain a cobalt nickel manganese sulfate mixed solution and a manganese slag; (b) adjusting the pH of the cobalt-nickel-manganese sulfate mixed solution to ≥5.5, and then separating the solid and the liquid to obtain a precipitated liquid and a precipitated residue; (c) adjusting the pH of the precipitated liquid to 2.0-3.5, mixing it with a composite extractant containing P507 and C272 and performing a first extraction to obtain a raffinate and a loaded organic phase; stripping the loaded organic phase to obtain a crude manganese sulfate solution; mixing the raffinate with a P204 extractant to remove impurities to obtain a de-impurified liquid; performing a second extraction on the de-impurified liquid using a P507 extractant to obtain a refined cobalt sulfate solution and a nickel-magnesium raffinate; performing a third extraction on the nickel-magnesium raffinate using a C272 extractant to obtain a refined nickel sulfate solution; (d) mixing the manganese slag with a sulfuric acid solution and a reducing agent and performing reduction leaching to obtain a reduction leaching solution; The reduction leaching solution is mixed with a sodium carbonate solution and subjected to an iron removal reaction, followed by solid-liquid separation to obtain yellow sodium ferroaluminate slag and an iron-removed liquid; (e) mixing the de-ironized liquid with the crude manganese sulfate solution, adding manganese fluoride thereto to remove calcium and magnesium; then performing solid-liquid separation to obtain de-fluorinated slag and de-calcified and magnesium-removed liquid; (f) mixing the decalcified and magnesium-free liquid with an aluminum source and performing a defluorination treatment, and then performing solid-liquid separation to obtain a defluorinated liquid and crude aluminum fluoride; (g) mixing the defluorinated liquid with sulfide and performing a copper-zinc removal treatment, and obtaining a copper-zinc removal liquid after solid-liquid separation; adding an alkali solution to the copper-zinc removal liquid to remove Co, Ni, Al, and Sc, and then performing solid-liquid separation to obtain a deweighted liquid; (h) After adjusting the pH of the deweighted liquid to acidic, a modified resin is used to remove Si, F, and P 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 is met: (1) The step of mixing the nickel cobalt hydroxide intermediate with a sulfuric acid solution and acid leaching specifically comprises: firstly mixing the nickel cobalt hydroxide intermediate with water to prepare a slurry, and then adding a concentrated sulfuric acid solution thereto; preferably, the liquid-to-solid ratio of the nickel cobalt hydroxide intermediate to the water is 1.8 to 2.5 g / ml; preferably, the pH of the reaction system of the acid leaching and / or the pH at the reaction end of the acid leaching is 0.5 to 1.0; (2) The acid leaching temperature is 80 to 90° C. (3) The acid leaching time is 3 to 6 hours; (4) the mass concentration of nickel in the leaching solution obtained after the acid leaching is ≤100 g / L; (5) The flocculant comprises at least one of an alkyl quaternary ammonium salt cationic surfactant solution, an ester quaternary ammonium salt cationic surfactant solution and a polymeric cationic surfactant solution; preferably, the polymeric cationic surfactant solution comprises a cationic polyacrylamide solution; preferably, the mass fraction of the polymeric cationic surfactant solution is 0.5‰ to 1.5‰; preferably, the addition amount of the polymeric cationic surfactant solution is 5 to 10 mg / L; (6) After adding the flocculant, stirring is performed for 10 to 30 minutes, and then standing for 30 to 60 minutes to carry out the sedimentation.

3. The method for preparing a precursor sulfate solution using a nickel cobalt hydroxide intermediate according to claim 1, characterized in that: In step (b), at least one of the following conditions is met: (1) using a slurry containing a nickel cobalt hydroxide intermediate or an alkaline solution to perform the adjustment; (2) After obtaining the precipitated residue, the precipitated residue is mixed with a dilute sulfuric acid solution or a concentrated sulfuric acid solution and leached to obtain a leachate, and then the leachate is mixed with the nickel cobalt hydroxide intermediate to obtain a slurry of the 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 is met: (1) adjusting the pH of the precipitated liquid by using a concentrated sulfuric acid solution or a dilute sulfuric acid solution; (2) The composite extractant containing P507 and C272 comprises a P507 extractant, a C272 extractant and a solvent in a mass ratio of 10 to 15:10 to 15:70 to 80, wherein the solvent is sulfonated kerosene; (3) the saponification rate of the first extraction is 50% to 55%; (4) the first extraction ratio O / A=1.5-2:1; (5) The loaded organic phase is stripped using a dilute sulfuric acid solution, wherein the molar concentration of the dilute sulfuric acid solution is 2.2 to 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 is met: (1) The sulfuric acid solution includes a dilute sulfuric acid solution or a concentrated sulfuric acid solution; (2) The reducing agent includes a hydrogen peroxide solution; preferably, the hydrogen peroxide solution is added for 3 to 4 hours; preferably, the hydrogen peroxide solution is kept warm for 1 hour after being added; (3) The reduction leaching temperature is 70 to 90° C.; (4) The temperature of the iron removal reaction is greater than 90° C. (5) adding the reducing leaching solution and the sodium carbonate solution simultaneously, and controlling the adding time to be 3 to 4 hours; after the adding is completed, continuing to keep warm for 2 to 5 hours to carry out the iron removal reaction; (6) The pH at the end point of the iron removal reaction is 4.0 to 5.

0.

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

7. The method for preparing a precursor sulfate solution using a nickel cobalt hydroxide intermediate according to claim 1, characterized in that: In step (f), at least one of the following conditions is met: (1) The aluminum source includes at least one of anhydrous aluminum sulfate, aluminum sulfate 18hydrate and polyaluminum sulfate; (2) adding the aluminum source according to a molar ratio of F element to Al element of 3.5 to 5.0:1; (3) The temperature of the defluorination treatment is 75 to 90° C.; (4) The defluorination treatment time is 4 to 6 hours.

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

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

10. Use of the refined cobalt sulfate solution, refined nickel sulfate solution and refined manganese sulfate solution obtained by the method for preparing a sulfate solution for a precursor using a nickel cobalt hydroxide intermediate as claimed 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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