Method for preparing high-purity cobalt chloride by recovering high cobalt hydroxide and high-purity cobalt chloride

Abstract

The invention belongs to the technical field of separation and purification, and particularly relates to a method for preparing high-purity cobalt chloride by recycling high cobalt hydroxide and high-purity cobalt chloride.The method for preparing high-purity cobalt chloride by recycling high cobalt hydroxide comprises the steps that high cobalt hydroxide is ground to obtain high cobalt hydroxide powder; washing the high-cobalt hydroxide powder with high-purity water, and filtering to obtain high-cobalt hydroxide filter residues; carrying out acidolysis treatment on the high cobalt hydroxide filter residue, adding an additive, and then carrying out precision filtration to obtain a cobalt chloride solution; the cobalt chloride solution is subjected to resin impurity removal, and cobalt chloride purified liquid is obtained; the cobalt chloride purified liquid is subjected to evaporative crystallization, centrifugal separation and vacuum drying, and high-purity cobalt chloride is obtained. The method provided by the invention solves the problems of difficult recovery and difficult purification of high cobalt hydroxide.

Description

Technical Field

[0001] The invention belongs to the technical field of separation and purification, and particularly relates to a method for recovering high cobalt hydroxide to prepare high-purity cobalt chloride and the high-purity cobalt chloride. Background Art

[0002] Cobalt hydroxide is a brownish-brown substance with strong oxidizing properties and is insoluble in water. In cobalt material-related industries such as electrolytic cobalt, cobalt hydroxide, and cobalt chloride, cobalt hydroxide mainly exists as a by-product or recycled product. Currently, there is no industry field that directly applies cobalt hydroxide. Cobalt is an important strategic resource in the fields of integrated circuits, magnetic recording, and energy storage, so cobalt hydroxide has a high recycling value.

[0003] Cobalt hydroxide has low purity and is difficult to separate. There is no report on the direct use of cobalt hydroxide to recover and prepare cobalt chloride. According to data, cobalt hydroxide dissolves in reducing acids such as hydrochloric acid to produce divalent cobalt ions, but the direct hydrochloric acid dissolution method cannot purify impurities such as Na, Si, Fe, Ni, Cu, and Zn, which undoubtedly increases the difficulty of subsequent purification; and the hydrochloric acid dissolution of cobalt hydroxide is accompanied by the generation of chlorine gas, which makes it difficult to purify impurities such as Na, Si, Fe, Ni, Cu, and Zn in a saturated chlorine environment.

[0004] Therefore, the recycling and reuse of cobalt hydroxide still needs further development and exploration. Summary of the invention

[0005] The main purpose of the invention is to provide a method for recovering cobalt hydroxide to prepare high-purity cobalt chloride and high-purity cobalt chloride. The method of the invention is to wash the ground cobalt hydroxide, perform acid hydrolysis and resin deep impurity removal to obtain a high-purity cobalt chloride solution, and then perform evaporation crystallization, centrifugal separation and vacuum drying to obtain high-purity cobalt chloride, thereby solving the problem of difficulty in recovering and purifying cobalt hydroxide.

[0006] In order to achieve the above objectives, the present invention provides the following technical solutions.

[0007] In a first aspect, the present invention provides a method for recovering cobalt hydroxide to prepare high-purity cobalt chloride, the method comprising the following steps:

[0008] Grinding cobalt hydroxide to obtain cobalt hydroxide powder;

[0009] Washing the cobalt hydroxide powder with high-purity water, and filtering to obtain cobalt hydroxide residue;

[0010] The cobalt hydroxide filter residue is subjected to acid hydrolysis treatment, and after adding an additive, is subjected to precise filtration to obtain a cobalt chloride solution;

[0011] The cobalt chloride solution is subjected to resin impurity removal to obtain a cobalt chloride purified solution;

[0012] The cobalt chloride purified solution is subjected to evaporation crystallization, centrifugal separation and vacuum drying to obtain high-purity cobalt chloride.

[0013] In some embodiments of the present invention, the particle size of the cobaltous hydroxide powder is 250 μm to 425 μm.

[0014] In some embodiments of the present invention, the cobalt hydroxide powder is washed with high-purity water until the conductivity of the filtrate is ≤1 μs / cm.

[0015] In some embodiments of the present invention, the resistivity of the high-purity water is ≥18 MΩ*cm.

[0016] In some embodiments of the present invention, the acidic solution used in the acid hydrolysis treatment includes hydrochloric acid.

[0017] In some embodiments of the present invention, the temperature of the acid hydrolysis treatment is 50° C. to 70° C., and the time of the acid hydrolysis treatment is 8 h to 12 h.

[0018] In some embodiments of the present invention, the weight ratio of the acidic solution to the cobaltous hydroxide powder is 1.1 to 1.4:1.

[0019] In some embodiments of the present invention, the hydrochloric acid is selected from high-grade pure hydrochloric acid.

[0020] In some embodiments of the present invention, the pore size of the filter medium used in the precision filtration is 1 μm to 2 μm.

[0021] In some embodiments of the present invention, the additive includes at least one of cobalt oxalate, cobalt formate, and cobalt citrate.

[0022] In some embodiments of the present invention, the concentration of the additive is 0.01 mol / L to 0.1 mol / L.

[0023] In some embodiments of the present invention, the additive is stirred after being added, and the stirring time is 1 hour to 2 hours.

[0024] In some embodiments of the present invention, the resin impurity removal uses at least one of a aminoacetic acid resin column and a thiourea resin column.

[0025] In some embodiments of the present invention, the cobalt chloride solution enters the lower end of the resin column at a flow rate of 4 BV / h to 6 BV / h and flows out of the upper end.

[0026] In some embodiments of the present invention, the volume ratio of the cobalt chloride solution to a single resin column is (20-30):1.

[0027] In some embodiments of the present invention, before the evaporation and crystallization, the pH value of the cobalt chloride purification solution is adjusted to 2-4.

[0028] In some embodiments of the present invention, the temperature of the evaporation crystallization is 100°C to 120°C.

[0029] In some embodiments of the present invention, when the volume of the solution is evaporated to 20% to 30% of the initial solution volume, heating is stopped to obtain a cobalt chloride solid-liquid mixture.

[0030] In some embodiments of the present invention, the vacuum drying is carried out at a temperature of 100° C. to 110° C. and for a time of 4 h to 5 h.

[0031] In a second aspect, the present invention provides high-purity cobalt chloride, which is prepared based on the method described in the first aspect.

[0032] In some embodiments of the present invention, the mass percentages of Fe, Ni, Cu, Si, Zn and Na impurities in the high-purity cobalt chloride are all lower than 0.0005%.

[0033] Compared with the prior art, the present invention achieves the following technical effects:

[0034] The key impurities Fe, Ni, Cu, Na, Zn and Si in the high-purity cobalt chloride prepared by the method of the present invention are all less than 0.0005%, thereby solving the problems of difficulty in recovering and purifying high cobalt hydroxide.

[0035] The high-purity cobalt chloride prepared in the present invention can be used as a raw material for high-end fields such as integrated circuits and batteries.

[0036] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented according to the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are listed below. DETAILED DESCRIPTION

[0037] The exemplary embodiments of the present invention will be described in more detail below with reference to specific embodiments. It should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to enable the scope of the present invention to be fully communicated to those skilled in the art.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which the present invention belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention; the terms "including" and "having" in the description and claims of the present invention and any variations thereof are intended to cover non-exclusive inclusions.

[0039] In the description of the embodiments of the present invention, technical terms such as "first" and "second" are only used to distinguish different objects and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features.

[0040] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present invention. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0041] In the description of the embodiments of the present invention, the term "and / or" is only a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may represent: A exists, A and B exist at the same time, and B exists. In addition, the character " / " in this document generally indicates that the associated objects before and after are in an "or" relationship.

[0042] In the description of the embodiments of the present invention, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0043] The invention provides a method for recovering high-cobalt hydroxide to prepare high-purity cobalt chloride. The key lies in washing, acid-lyzing and deeply removing impurities from the ground high-cobalt hydroxide to obtain a high-purity cobalt chloride solution, and then performing evaporation crystallization, centrifugal separation and vacuum drying to obtain the high-purity cobalt chloride.

[0044] Cobalt hydroxide is a recycled material, the main component of which is cobalt, and the impurities mainly include Na (active impurity), SiO2 (inert impurity), Fe, Ni, Cu, Zn (transition metal impurities), etc.

[0045] Since a large amount of soluble sodium chloride impurities are entrained in the cobalt hydroxide powder, it cannot be removed in the subsequent resin deep impurity removal and precision filtration process. By utilizing the insolubility of cobalt hydroxide and the water solubility of sodium chloride, the sodium content can be greatly reduced by washing the cobalt hydroxide with high-purity water.

[0046] After the acid hydrolysis of cobalt hydroxide, cobalt and transition metal impurities with similar properties such as Fe and Ni are dissolved, and the inert impurity silica will be suspended in the solution in the form of insoluble matter. The silica particles are very small and cannot be removed by resin impurity removal. In addition, there is blockage of the resin, which affects its deep impurity removal effect. Traditional filtration separation technology cannot achieve the purpose of removing silica impurities. The use of precision filtration method can effectively remove silica with tiny particles.

[0047] The main purpose of resin impurity removal is to deeply remove transition metal impurities such as Fe, Ni, and Cu. These impurities have similar properties to cobalt chloride, and traditional physical and chemical methods have poor separation effects. If resin deep impurity removal is not performed, transition metal impurities will be mixed in the cobalt chloride crystals, seriously affecting its purity and application. The resin uses its internal specific functional groups to selectively adsorb transition metal impurities to achieve the purpose of deep impurity removal.

[0048] Active impurities Na, inert impurities SiO2, transition metals Fe, Ni, Cu and other impurities are removed respectively through three impurity removal steps of high-purity water washing, precision filtration and resin deep impurity removal. The three steps work together, and any one step alone cannot achieve the purpose of preparing high-purity cobalt chloride crystals.

[0049] The method for recovering cobalt hydroxide to prepare high-purity cobalt chloride in the present invention is carried out according to the following steps.

[0050] (1) Grinding cobalt hydroxide.

[0051] In an embodiment of the present invention, cobalt hydroxide is ground to obtain cobalt hydroxide powder.

[0052] In some embodiments of the present invention, the recovered cobaltous hydroxide is ground into powder, and sieved with a 40-60 mesh sieve to obtain cobaltous hydroxide powder.

[0053] In some embodiments of the present invention, the particle size of the cobalt hydroxide powder is 250 μm to 425 μm, for example, the particle size can be one of 250 μm, 270 μm, 300 μm, 320 μm, 350 μm, 380 μm, 400 μm, 425 μm or any value satisfying the above range.

[0054] (2) Wash with water.

[0055] In the embodiment of the present invention, the cobalt hydroxide powder obtained in step (1) is washed with high-purity water, and the cobalt hydroxide residue is obtained by filtration.

[0056] In some embodiments of the present invention, the high-purity water used for water washing satisfies a resistivity of ≥18 MΩ*cm.

[0057] In some embodiments of the present invention, the cobalt hydroxide powder is washed with high-purity water until the conductivity of the filtrate is ≤1 μs / cm, and the cobalt hydroxide residue is obtained by filtration.

[0058] (3) Acid hydrolysis.

[0059] In an embodiment of the present invention, the cobalt hydroxide residue obtained in step (2) is subjected to acid hydrolysis, and after the acid hydrolysis, a proper amount of additives are added and then finely filtered to obtain a cobalt chloride solution.

[0060] In some embodiments of the present invention, the acid solution used in the acid hydrolysis treatment includes hydrochloric acid, such as using high-grade pure hydrochloric acid for the acid hydrolysis treatment.

[0061] In some embodiments of the present invention, the weight ratio of the acidic solution to the cobaltous hydroxide powder is 1.1 to 1.4:1, for example, it can be one of 1.1:1, 1.2:1, 1.3:1, 1.4:1 or any value satisfying the above range.

[0062] In some embodiments of the present invention, the temperature of the acid hydrolysis treatment can be 50°C to 70°C, for example, the temperature can be one of 50°C, 55°C, 60°C, 65°C, 70°C or any value satisfying the above range.

[0063] In some embodiments of the present invention, the acid hydrolysis time can be 8 h to 12 h. For example, the acid hydrolysis time can be one of 8 h, 9 h, 10 h, 10.5 h, 11 h, 11.5 h, 12 h or any value that satisfies the above range.

[0064] In some embodiments of the present invention, the additive may be at least one of cobalt oxalate, cobalt formate, and cobalt citrate.

[0065] In some embodiments of the present invention, the volume ratio of the additive to the cobalt chloride solution obtained after acid hydrolysis treatment is 1:10 to 80, for example, the volume ratio can be one of 1:10, 1:20, 1:30, 1:40, 1:50, 1:60, 1:70, 1:80 or any value satisfying the above range.

[0066] In some embodiments of the present invention, the concentration of the additive can be 0.01mol / L to 0.1mol / L, for example, the concentration of the additive is one of 0.01mol / L, 0.02mol / L, 0.03mol / L, 0.04mol / L, 0.05mol / L, 0.06mol / L, 0.07mol / L, 0.08mol / L, 0.09mol / L, 0.1mol / L or any value satisfying the above range.

[0067] In some embodiments of the present invention, the additive is stirred after being added, and the stirring time may be 1 hour to 2 hours, for example, stirring for 1 hour, 1.5 hours, 2 hours or any value satisfying the above range.

[0068] In some embodiments of the present invention, the pore size of the filter medium used in precision filtration is 1 μm to 2 μm, for example, the pore size is one of 1 μm, 1.2 μm, 1.5 μm, 1.8 μm, 2 μm or any value that satisfies the above range, thereby obtaining a cobalt chloride solution.

[0069] (4) Deep removal of impurities from resin.

[0070] In an embodiment of the present invention, the cobalt chloride solution is subjected to resin impurity removal to obtain a cobalt chloride purified solution.

[0071] In some embodiments of the present invention, the resin impurity removal uses at least one of a aminoacetic acid resin column and a thiourea resin column.

[0072] In some embodiments of the present invention, aminoacetic acid resin and thiourea resin are used for resin impurity removal. For example, aminoacetic acid resin and thiourea resin are respectively filled in polypropylene (PP) resin columns to obtain aminoacetic acid resin columns and thiourea resin columns. The ratio of aminoacetic acid resin columns to thiourea resin columns can be 1:2 or 2:3. Multiple resin columns are used in series without any order requirement.

[0073] In some embodiments of the present invention, the cobalt chloride solution enters from the lower end of the resin column at a flow rate of 4BV / h to 6BV / h and flows out from the upper end. Exemplarily, the flow rate of the cobalt chloride solution can be one of 4BV / h, 5BV / h, 6BV / h or any value satisfying the above range.

[0074] In some embodiments of the present invention, the volume ratio of the total volume of the cobalt chloride solution used for resin impurity removal to the volume of a single resin column is (20-30): 1. Exemplarily, the volume ratio of the cobalt chloride solution to the single resin column can be one of 20: 1, 21: 1, 22: 1, 23: 1, 24: 1, 25: 1, 26: 1, 27: 1, 28: 1, 29: 1, 30: 1 or any value satisfying the above range.

[0075] (5) Evaporation crystallization.

[0076] In an embodiment of the present invention, the purified cobalt chloride solution obtained in step (4) is evaporated and crystallized.

[0077] It is worth mentioning that before evaporation and crystallization, the pH value of the cobalt chloride purification solution is adjusted to 2-4, for example, the pH value is adjusted to one of 2, 3, 4 or any value satisfying the above range.

[0078] In some embodiments of the present invention, the evaporation crystallization temperature can be 100°C to 120°C, for example, the evaporation crystallization temperature is one of 100°C, 105°C, 110°C, 115°C, 120°C or any value satisfying the above range.

[0079] In some embodiments of the present invention, when the volume of the solution evaporates to 20% to 30% of the initial solution volume, a solid-liquid mixture state is present, and heating is stopped to obtain a cobalt chloride solid-liquid mixture.

[0080] (6) Centrifugal separation.

[0081] In an embodiment of the present invention, the cobalt chloride solid-liquid mixture obtained in step (5) is centrifuged to obtain water-enriched cobalt chloride.

[0082] (7) Vacuum drying.

[0083] In an embodiment of the present invention, the water-rich cobalt chloride is transferred into a vacuum drying oven and dried at 100° C. to 110° C. for 4 to 5 hours to obtain high-purity cobalt chloride.

[0084] Exemplarily, the vacuum drying temperature is one of 100° C., 105° C., 110° C., or any value within the above range. The drying time is one of 4 h, 4.5 h, 5 h, or any value within the above range.

[0085] The present invention also provides high-purity cobalt chloride, which is prepared based on the above method.

[0086] The mass percentages of Fe, Ni, Cu, Si, Zn and Na impurities in the high-purity cobalt chloride of the present invention are all lower than 0.0005%, and the high-purity cobalt chloride can be used as a material in high-end fields such as integrated circuits and batteries.

[0087] Unless otherwise defined, the technical terms used in the following examples have the same meanings as those generally understood by those skilled in the art to which the present invention belongs. The experimental reagents used in the following examples, unless otherwise specified, are all conventional biochemical reagents; the raw materials, instruments and equipment used in the following examples, etc., can all be purchased on the market or can be obtained by existing methods; the amounts of the experimental reagents, unless otherwise specified, are the amounts of reagents used in conventional experimental operations; the experimental methods, unless otherwise specified, are all conventional methods.

[0088] Example 1

[0089] A method for recovering high cobalt hydroxide to prepare high-purity cobalt chloride, the method is as follows:

[0090] 1.5 kg of cobalt hydroxide was ground into powder, and the cobalt hydroxide powder was collected by sieving with a 60-mesh sieve. The cobalt hydroxide powder was rinsed with high-purity water with a resistivity of ≥18MΩ*cm until the conductivity of the filtrate was less than 1μs / cm, and the water was filtered to obtain the cobalt hydroxide residue. The cobalt hydroxide residue and high-grade pure hydrochloric acid were mixed in a weight ratio of 1:1.3 and acid-hydrolyzed for 12 hours. The temperature of the acid hydrolysis process was controlled at 70°C. After acid hydrolysis, 1L of cobalt citrate with a concentration of 0.1mol / L was added, stirred for 2 hours, and then finely filtered to obtain a cobalt chloride solution. The cobalt chloride solution was sequentially passed through an aminoacetic acid resin column (90Na), a thiourea resin column (S9100), and a thiourea resin column (S9100) for resin deep impurity removal. The flow rate of the cobalt chloride solution was 6BV / h, and the volume ratio of the cobalt chloride solution to a single resin column was 20:1 to obtain a cobalt chloride purified solution. The pH value of the cobalt chloride purified solution is adjusted to 3 by using high-grade pure hydrochloric acid, and then evaporated and crystallized at 105° C. When the volume of the solution is 20% of the initial solution volume, heating is stopped to obtain a cobalt chloride solid-liquid mixture, and then the cobalt chloride solid-liquid mixture is centrifuged to obtain water-rich cobalt chloride, and finally the water-rich cobalt chloride is vacuum dried at 110° C. for 4 hours to obtain high-purity cobalt chloride crystals.

[0091] Example 2

[0092] A method for recovering high cobalt hydroxide to prepare high-purity cobalt chloride, the method is as follows:

[0093] 1.5 kg of cobalt hydroxide was ground into powder, and the cobalt hydroxide powder was collected by sieving with a 40-mesh sieve. The cobalt hydroxide powder was rinsed with high-purity water with a resistivity of ≥18MΩ*cm until the conductivity of the filtrate was less than 1μs / cm, and the water was filtered to obtain the cobalt hydroxide residue. The cobalt hydroxide residue and high-grade pure hydrochloric acid were mixed and acid-hydrolyzed for 10 hours in a weight ratio of 1:1.2. The temperature of the acid hydrolysis process was controlled at 60°C. After acid hydrolysis, 10L of cobalt oxalate with a concentration of 0.01mol / L was added, stirred for 1h, and then finely filtered to obtain a cobalt chloride solution. The cobalt chloride solution was sequentially passed through an aminoacetic acid resin column (90Na), a thiourea resin column (S9100), and a thiourea resin column (S9100) for resin deep impurity removal. The flow rate of the cobalt chloride solution was 5BV / h, and the volume ratio of the cobalt chloride solution to a single resin column was 30:1 to obtain a cobalt chloride purified solution. The pH value of the cobalt chloride purification solution is adjusted to 4 by using high-grade pure hydrochloric acid, and then evaporated and crystallized at 105° C. When the volume of the solution is 30% of the initial solution volume, heating is stopped to obtain a cobalt chloride solid-liquid mixture, and then the cobalt chloride solid-liquid mixture is centrifuged to obtain water-rich cobalt chloride, and finally the water-rich cobalt chloride is vacuum dried at 110° C. for 5 hours to obtain high-purity cobalt chloride crystals.

[0094] Comparative Example 1

[0095] The remaining operations are the same as those in Example 1, except that the cobalt hydroxide powder in Comparative Example 1 is not rinsed with high-purity water.

[0096] Comparative Example 2

[0097] The remaining operations are the same as those in Example 1, except that in Comparative Example 2, the cobalt chloride solution is not subjected to resin deep impurity removal.

[0098] Comparative Example 3

[0099] The remaining operations are the same as those in Example 1, except that in Comparative Example 3, the high-cobalt hydroxide residue is not subjected to precision filtration after acid hydrolysis treatment.

[0100] Performance Testing

[0101] Cobalt chloride purity analysis: refer to GB / T 39486-2020 test standard.

[0102] Table 1 Summary of the purity analysis results of the cobalt chloride crystals obtained in the embodiments and comparative examples

[0103]

[0104] It can be seen from Table 1 that the mass percentages of Fe, Ni, Cu, Si, Zn and Na impurities in the high-purity cobalt chloride prepared in the present invention are all lower than 0.0005%. Compared with Example 1, the Na content in Comparative Example 1 is higher, the Fe, Ni, Cu and Zn contents in Comparative Example 2 are higher, and the Si content in Comparative Example 3 is higher. In the present invention, active impurity Na, inert impurity SiO2, transition metal Fe, Ni, Cu and other impurities are removed respectively through three impurity removal steps of high-purity water washing, precision filtration and resin deep impurity removal, and the three steps cooperate with each other, and any one step alone cannot achieve the purpose of preparing high-purity cobalt chloride crystals.

[0105] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A method for recovering cobalt hydroxide to prepare high-purity cobalt chloride, characterized in that: The following steps are involved: Grinding cobalt hydroxide to obtain cobalt hydroxide powder; Washing the cobalt hydroxide powder with high-purity water, and filtering to obtain cobalt hydroxide residue; The cobalt hydroxide residue is subjected to acid hydrolysis treatment, and after adding additives, it is subjected to precision filtration to obtain a cobalt chloride solution; The cobalt chloride solution is subjected to resin impurity removal to obtain a cobalt chloride purified solution; The cobalt chloride purified solution is subjected to evaporation crystallization, centrifugal separation and vacuum drying to obtain high-purity cobalt chloride.

2. The method according to claim 1, characterized in that The particle size of the cobalt hydroxide powder is 250 μm to 425 μm.

3. The method according to claim 1, characterized in that Washing the cobalt hydroxide powder with high-purity water until the conductivity of the filtrate is ≤1 μs / cm; Preferably, the resistivity of the high-purity water is ≥18 MΩ*cm.

4. The method according to claim 1, characterized in that The acid solution used in the acid hydrolysis treatment includes hydrochloric acid; Preferably, the temperature of the acid hydrolysis treatment is 50°C to 70°C, and the time of the acid hydrolysis treatment is 8h to 12h; Preferably, the weight ratio of the acidic solution to the cobalt hydroxide powder is 1.1 to 1.4:1; Preferably, the hydrochloric acid is selected from high-grade pure hydrochloric acid.

5. The method according to claim 1, characterized in that The pore size of the filter medium used in the precision filtration is 1 μm to 2 μm.

6. The method according to claim 1, characterized in that The additive includes at least one of cobalt oxalate, cobalt formate, and cobalt citrate; Preferably, the concentration of the additive is 0.01 mol / L to 0.1 mol / L; Preferably, the additive is stirred after being added, and the stirring time is 1 hour to 2 hours.

7. The method according to claim 1, characterized in that The resin impurity removal adopts at least one of aminoacetic acid resin column and thiourea resin column; Preferably, the cobalt chloride solution enters from the lower end of the resin column at a flow rate of 4BV / h to 6BV / h and flows out from the upper end; Preferably, the volume ratio of the cobalt chloride solution to a single resin column is (20-30):

1.

8. The method according to claim 1, characterized in that Before the evaporation and crystallization, the pH value of the cobalt chloride purification solution is adjusted to 2-4; Preferably, the temperature of the evaporation crystallization is 100° C. to 120° C.; preferably, when the volume of the solution is evaporated to 20% to 30% of the initial solution volume, the heating is stopped to obtain a cobalt chloride solid-liquid mixture; Preferably, the vacuum drying is carried out at a temperature of 100° C. to 110° C. and for a time of 4 to 5 hours.

9. A high-purity cobalt chloride, characterized in that: The high-purity cobalt chloride is prepared based on the method described in any one of claims 1-8.

10. The high-purity cobalt chloride according to claim 9, characterized in that The mass percentages of Fe, Ni, Cu, Si, Zn and Na impurities in the high-purity cobalt chloride are all lower than 0.0005%.

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