Method for removing calcium and magnesium from cobalt-nickel hydroxide raw material

Abstract

The invention discloses a method for removing calcium and magnesium from a cobalt-nickel hydroxide raw material, and relates to the technical field of hydrometallurgy. The method comprises the following steps: slurrying a cobalt-nickel hydroxide raw material and deionized water, and washing the slurry to remove residual water-soluble calcium / magnesium at normal temperature in a carbon dioxide pressurized stirring manner, namely primary impurity removal; then, ferrous sulfate is used as an auxiliary rinsing agent for further washing and removing calcium / magnesium, and secondary impurity removal is achieved; the secondary impurity removal material is mixed and dissolved with sulfuric acid-ammonium phosphate, after the pH value is adjusted through ammonia water, most of residual calcium / magnesium ions are compounded to generate calcium phosphate / magnesium ammonium precipitate to be separated out, and at the moment, the filtered cobalt-nickel material is subjected to tertiary purification and impurity removal. The nickel-cobalt material subjected to three-time calcium / magnesium pre-removal can significantly reduce the impurity concentration of the acid-dissolved liquid, and lays a solid foundation for shortening the extraction stage number, reducing the extraction workload, reducing the extraction input cost and improving the product quality for a subsequent extraction production line.

Description

Technical Field

[0001] The invention relates to the technical field of hydrometallurgy, in particular to a method for pre-removing calcium and magnesium from a cobalt-nickel hydroxide raw material. Background Art

[0002] Mixed nickel-cobalt hydroxide raw materials are important raw materials for the production of battery-grade nickel sulfate and cobalt sulfate. With the rapid development of the new energy industry, the demand for ternary batteries with nickel sulfate and cobalt sulfate as the main components has gradually increased. Therefore, the preparation of high-purity nickel sulfate and cobalt sulfate is a new requirement for the development of the industry.

[0003] At present, in the process of preparing battery-grade nickel sulfate and cobalt sulfate by hydrometallurgy, extraction and chemical precipitation methods are usually used to remove calcium and magnesium; the extraction method uses P204 to extract and separate calcium, and C272 to extract and separate magnesium; this method has obvious disadvantages. When P204 extracts and separates calcium, a large amount of calcium sulfate crystals easily clog the extraction tank, and regular cleaning and slag removal are required, affecting normal production; C272 extracts and separates magnesium and requires a long extraction stage, which is difficult to extract, requires high equipment requirements, and has high production costs. The precipitant used in the chemical precipitation method is generally fluoride, but the toxicity of fluoride can endanger human health and cause environmental pollution. Some researchers also use a mixture of oxalic acid, sodium oxalate, and ammonium oxalate as a precipitant to remove calcium and magnesium. Although the use of toxic fluoride is avoided, new impurities are introduced, and the impurities are not easy to remove. Therefore, it is of great significance to select a non-toxic precipitant that does not introduce new impurities to remove calcium and magnesium impurities. Summary of the invention

[0004] The object of the present invention is to provide a method for removing calcium and magnesium from cobalt nickel hydroxide raw materials to solve the problems existing in the prior art.

[0005] In order to solve the above technical problems, the present invention provides the following technical solution: a method for removing calcium and magnesium from cobalt nickel hydroxide raw materials, comprising the following preparation steps: (1) Take 50g of cobalt nickel hydroxide raw material, add 250-400mL of deionized water, maintain the temperature at 10-50°C, maintain the carbon dioxide pressure at 0.30-0.65MPa, stir at 240-650rpm for 30-60min, filter out the water-soluble calcium and magnesium solution, and send the nickel-cobalt filter residue to the next step of purification; (2) According to the residual calcium and magnesium content in the residue, add 1-2g of solid ferrous sulfate; adjust the pH to 5 with dilute sulfuric acid, react for 2-8h, separate the solid and liquid to obtain filtrate and residue, and wash the residue with water spray; put the washed residue into a drying oven to dry to obtain a secondary impurity-removed residue; (3) Three times of impurity removal: acidify the filter residue from the second impurity removal with sulfuric acid-ammonium phosphate in a volume ratio of 1:0.5-1.5, control the temperature at 65-80°C, and leach for 1-2.5 hours, then add deionized water 2-3 times the weight of the filter residue from the first impurity removal, and leach for 1-2 hours to obtain an intermediate product solution; add ammonia water to adjust the pH to 5.5 and react for 1-4.0 hours. After the reaction is completed, filter out the calcium phosphate / ammonium magnesium precipitate under a negative pressure of -0.075 MPa to obtain a purified nickel-cobalt solution, and filter out the precipitate under negative pressure for 4-6 hours. After the reaction is completed, filter out the precipitate to obtain the final impurity-removed raw material solution.

[0006] Furthermore, in the step (1), the raw material composition ratio of cobalt nickel hydroxide is: 3.13% Co, 37.13% Ni, 0.12% Cu, 0.37% Fe, 5.23% Mn, 0.52% Zn, 0.011% Ca, 6.57% Mg, 0.41% Na, 0.0011% Cd, and 0.0099% Cr.

[0007] Furthermore, the concentration of the dilute sulfuric acid in step (2) is 25-50wt%.

[0008] Furthermore, in step (2), the liquid-to-solid ratio of the spray washing water to the filter residue is 5:1.

[0009] Furthermore, in step (2), the product is dried in a drying oven at 80° C. for 2 hours.

[0010] Furthermore, the concentration of sulfuric acid in step (3) is 85%.

[0011] Furthermore, the concentration of ammonium phosphate in step (3) is 15%.

[0012] Furthermore, the concentration of ammonia water in step (3) is 0.01 mol / L.

[0013] Furthermore, in step (3), the negative pressure filtration pressure is -0.075 MPa.

[0014] Furthermore, the filtration temperature in step (3) is 65-80°C.

[0015] Compared with the prior art, the beneficial effects achieved by the present invention are: First, the present invention slurries cobalt nickel hydroxide raw materials and deionized water at a certain solid-liquid ratio, washes water-soluble calcium / magnesium in the material with a carbon dioxide pressurized stirring device at room temperature, and then uses ferrous sulfate as a calcium and magnesium removal agent to perform secondary impurity removal; the secondary impurity removal has a high calcium and magnesium removal rate, a short reaction time, and is easy to remove the introduced iron element, and has a low pressure on the subsequent extraction stage; ferrous sulfate is used as an auxiliary precipitant to remove calcium and magnesium, thereby avoiding the use of toxic fluoride and oxalate solution that can introduce new impurities as precipitants, reducing pollution to the environment; avoiding the influence of using an extractant to remove calcium and magnesium on the system; and the newly introduced iron element can be hydrolyzed and precipitated into iron slag through the third impurity removal in the subsequent purification process, thereby realizing comprehensive recycling of resources; Secondly, the cobalt-nickel hydroxide after the second impurity removal is purified for a third time using a sulfuric acid / ammonium phosphate / ammonia system to precipitate the remaining calcium / magnesium / iron ions into calcium phosphate / ammonium magnesium and ammonium sulfonate iron alum, etc., which are effectively separated from the cobalt / nickel solution; after the third impurity removal, the calcium concentration in the filtrate is less than 0.001g / L, and the magnesium concentration is less than 1.0g / L; The present invention can achieve a calcium and magnesium removal rate of more than 85% in the cobalt nickel hydroxide raw material after three purification treatments, provides quality assurance for each process from material preparation to acid leaching and then to extraction, and has a significant reference value for optimizing extraction process operation, reducing manual labor intensity and reducing investment cost; the present invention has low production cost and has industrial application prospects. DETAILED DESCRIPTION

[0016] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0017] Example 1; (1) The composition ratio of the cobalt nickel hydroxide raw material is: 3.13% Co, 37.13% Ni, 0.12% Cu, 0.37% Fe, 5.23% Mn, 0.52% Zn, 0.011% Ca, 6.57% Mg, 0.41% Na, 0.0011% Cd, and 0.0099% Cr; 50 g of the cobalt nickel hydroxide raw material was added with 250 mL of deionized water, and the mixture was stirred at 240 rpm for 30 min at room temperature of 11° C. and a carbon dioxide autoclave pressure of 0.3 MPa, and then filtered to obtain a once-purified cobalt nickel slag; (2) After the stirring is completed, the impurities are removed once: 2 g of ferrous sulfate solid is added according to the amount of calcium and magnesium; the pH is adjusted to 5 with 25 wt % dilute sulfuric acid, the reaction is carried out for 8 h, and the filtrate and filter residue are obtained by solid-liquid separation. The filter residue is washed by water spraying, and the liquid-solid ratio of water to the filter residue is 5:1; the washed filter residue is placed in a drying oven and dried at 50 ° C for 2 h to obtain a first impurity-removed filter residue; (3) Three times of impurity removal: The filter residue from the second impurity removal was mixed with sulfuric acid-ammonium phosphate in a volume ratio of 1:0.5, and the concentration of sulfuric acid was 85%. Then, deionized water twice the weight of the filter residue from the first impurity removal was added for stirring and slurrying. The temperature was controlled at 65°C and the leaching reaction was carried out for 1.5 hours to obtain a mixed solution of multiple metal ions. At this time, ammonia water with a concentration of 1 mol / L was used to adjust the pH to 5.5. After continuing the reaction for 1.0 hour, the calcium phosphate / ammonium magnesium precipitate residue formed in the slurry was filtered out at a vacuum negative pressure of -0.075 MPa to obtain a relatively pure cobalt-nickel solution.

[0018] Example 2; (1) The composition ratio of the cobalt nickel hydroxide raw material is: 3.13% Co, 37.13% Ni, 0.12% Cu, 0.37% Fe, 5.23% Mn, 0.52% Zn, 0.011% Ca, 6.57% Mg, 0.41% Na, 0.0011% Cd, and 0.0099% Cr; 50 g of the cobalt nickel hydroxide raw material was added with 350 mL of deionized water, the temperature was raised to 23° C., and the reaction was stirred at 350 rpm for 40 min under a carbon dioxide autoclave pressure of 0.4 MPa, and then filtered to obtain a once purified cobalt nickel slag; (2) After the stirring is completed, the impurities are removed once: 1.5 g of ferrous sulfate solid is added according to the amount of calcium and magnesium; the pH is adjusted to 5 with 35 wt % dilute sulfuric acid, the reaction is carried out for 5 h, and the solid-liquid separation is performed to obtain a filtrate and a filter residue. The filter residue is washed by spraying water, and the liquid-solid ratio of water to the filter residue is 5:1; the washed filter residue is placed in a drying oven and dried at 50° C. for 2 h to obtain a filter residue with impurities removed once; (3) Three times of impurity removal: The filter residue from the second impurity removal was mixed with sulfuric acid-ammonium phosphate in a volume ratio of 1:0.55, and the concentration of sulfuric acid was 85%. Then, deionized water twice the weight of the filter residue from the first impurity removal was added for stirring and slurrying. The temperature was controlled at 69°C and the leaching reaction was carried out for 1.4 hours to obtain a mixed solution of multiple metal ions. At this time, ammonia water with a concentration of 1 mol / L was used to adjust the pH to 5.5. After continuing the reaction for 1.5 hours, the calcium phosphate / ammonium magnesium precipitate residue formed in the slurry was filtered out at a vacuum negative pressure of -0.075 MPa to obtain a relatively pure cobalt-nickel solution.

[0019] Example 3; (1) The composition ratio of the cobalt nickel hydroxide raw material is: 3.13% Co, 37.13% Ni, 0.12% Cu, 0.37% Fe, 5.23% Mn, 0.52% Zn, 0.011% Ca, 6.57% Mg, 0.41% Na, 0.0011% Cd, and 0.0099% Cr; 50 g of the cobalt nickel hydroxide raw material was added with 400 mL of deionized water, and the mixture was stirred at 430 rpm for 30 min under the conditions of heating to 32° C. and carbon dioxide autoclave pressure of 0.5 MPa, and then filtered to obtain a once purified cobalt nickel slag; (2) After the stirring is completed, the impurities are removed once: 1 g of ferrous sulfate solid is added according to the amount of calcium and magnesium; the pH is adjusted to 5 with 50 wt % dilute sulfuric acid, the reaction is carried out for 2 h, and the solid-liquid separation is performed to obtain a filtrate and a filter residue. The filter residue is washed by spraying water, and the liquid-solid ratio of water to the filter residue is 5:1; the washed filter residue is placed in a drying oven and dried at 80 ° C for 2 h to obtain a secondary purification filter residue; (3) Three times of impurity removal: The filter residue from the second impurity removal was mixed with sulfuric acid-ammonium phosphate in a volume ratio of 1:0.6, and the concentration of sulfuric acid was 85%. Then, 2.5 times the weight of the filter residue from the first impurity removal was added with deionized water, stirred and slurried. The temperature was controlled at 72°C and the leaching reaction was carried out for 1.3 hours to obtain a mixed solution of multiple metal ions. At this time, the pH was adjusted to 5.5 with ammonia water at a concentration of 1 mol / L. After continuing the reaction for 2.0 hours, the calcium phosphate / ammonium magnesium precipitate residue formed in the slurry was filtered out at a vacuum pressure of -0.075 MPa to obtain a relatively pure cobalt-nickel solution.

[0020] Example 4; (1) The composition ratio of the cobalt nickel hydroxide raw material is: 3.13% Co, 37.13% Ni, 0.12% Cu, 0.37% Fe, 5.23% Mn, 0.52% Zn, 0.011% Ca, 6.57% Mg, 0.41% Na, 0.0011% Cd, and 0.0099% Cr; 50 g of the cobalt nickel hydroxide raw material was added with 250 mL of deionized water, and the mixture was stirred at 520 rpm for 30 min under the conditions of heating to 41° C. and carbon dioxide autoclave pressure of 0.55 MPa, and then filtered to obtain a once purified cobalt nickel slag; (2) After the stirring is completed, the impurities are removed once: 1.5 g of ferrous sulfate solid is added according to the amount of calcium and magnesium; the pH is adjusted to 5 with 35 wt % dilute sulfuric acid, the reaction is carried out for 6 h, and the solid-liquid separation is performed to obtain a filtrate and a filter residue. The filter residue is washed by spraying water, and the liquid-solid ratio of water to the filter residue is 5:1; the washed filter residue is placed in a drying oven and dried at 50° C. for 2 h to obtain a filter residue with impurities removed once; (3) Three times of impurity removal: The filter residue from the second impurity removal was mixed with sulfuric acid-ammonium phosphate in a volume ratio of 1:0.65, and the concentration of sulfuric acid was 85%. Then, 3.0 times the weight of the filter residue from the first impurity removal was added with deionized water, stirred and slurried. The temperature was controlled at 75°C and the leaching reaction was carried out for 1.2 hours to obtain a mixed solution of multiple metal ions. At this time, the pH was adjusted to 5.5 with ammonia water with a concentration of 1 mol / L. After continuing the reaction for 2.5 hours, the calcium phosphate / ammonium magnesium precipitate residue formed in the slurry was filtered out with a vacuum negative pressure of -0.075 MPa to obtain a relatively pure cobalt-nickel solution.

[0021] Example 5; (1) The composition ratio of the cobalt nickel hydroxide raw material is: 3.13% Co, 37.13% Ni, 0.12% Cu, 0.37% Fe, 5.23% Mn, 0.52% Zn, 0.011% Ca, 6.57% Mg, 0.41% Na, 0.0011% Cd, and 0.0099% Cr; 50 g of the cobalt nickel hydroxide raw material was added with 380 mL of deionized water, and the mixture was stirred at 630 rpm for 30 min under the conditions of the temperature rising to 46° C. and the carbon dioxide autoclave pressure being 0.60 MPa, and then filtered to obtain a once purified cobalt nickel slag; (2) After the stirring is completed, the impurities are removed once: 2 g of ferrous sulfate solid is added according to the amount of calcium and magnesium; the pH is adjusted to 5 with 35 wt % dilute sulfuric acid, the reaction is carried out for 4.5 h, and the solid-liquid separation is performed to obtain a filtrate and a filter residue. The filter residue is washed by spraying water, and the liquid-solid ratio of water to the filter residue is 5:1; the washed filter residue is placed in a drying oven and dried at 50 ° C for 2 h to obtain a filter residue with impurities removed once; (3) Three times of impurity removal: The filter residue from the second impurity removal was mixed with sulfuric acid-ammonium phosphate in a volume ratio of 1:0.70, and the concentration of sulfuric acid was 85%. Then, 3.5 times the weight of the filter residue from the first impurity removal was added with deionized water, stirred and slurried. The temperature was controlled at 80°C and the leaching reaction was carried out for 1.0 h to obtain a mixed solution of multiple metal ions. At this time, the pH was adjusted to 5.5 with ammonia water at a concentration of 1 mol / L. After continuing the reaction for 3.5 h, the calcium phosphate / ammonium magnesium precipitate residue formed in the slurry was filtered out at a vacuum negative pressure of -0.075 MPa to obtain a relatively pure cobalt-nickel solution.

[0022] Comparative Example 1: The difference between Comparative Example 1 and Example 3 is that step (1) is different, and step (1) is changed to: the proportion of the raw material components of cobalt nickel hydroxide is: 3.13% Co, 37.13% Ni, 0.12% Cu, 0.37% Fe, 5.23% Mn, 0.52% Zn, 0.011% Ca, 6.57% Mg, 0.41% Na, 0.0011% Cd, 0.0099% Cr; 50 g of cobalt nickel hydroxide raw material is taken, 400 mL of deionized water is added, the temperature is raised to 32° C. and kept warm for 30 minutes, and then filtered to obtain a once-purified cobalt nickel slag; the remaining steps are the same as those in Example 3.

[0023] Comparative Example 2: The difference between Comparative Example 2 and Example 3 is that step (3) is different. Step (3) is changed to: the secondary impurity removal residue and sulfuric acid-ammonium phosphate are mixed and added in a volume ratio of 1:0.6, the concentration of sulfuric acid is 85%, and then 2.5 times the weight of the primary impurity removal residue is added with deionized water, stirred and slurried, the temperature is controlled at 72°C, and the leaching reaction is carried out for 1h / 20min to obtain a relatively pure cobalt-nickel solution; the remaining steps are the same as those in Example 3.

[0024] Effect example Table 1 below shows the performance analysis results of removing calcium and magnesium using a cobalt nickel hydroxide raw material using Examples 1 to 5 of the present invention and Comparative Examples 1 to 2.

[0025] Table 1

[0026] From the comparison of the experimental data of the embodiment and the comparative example, it can be found that after three pre-purification and impurity removal, the calcium content in the nickel-cobalt filter material residue is less than 0.003%, and the magnesium content is less than 1%. The calcium and magnesium removal rate after treatment by this method can reach more than 85%, and the cobalt and nickel loss rate is controlled within 0.1%. It can achieve the removal of impurities such as calcium and magnesium in the material preparation stage, greatly reducing the impurities such as calcium, magnesium and iron flowing into the extraction line solution, and significantly reducing the load of the extraction equipment and the working pressure of manual operation.

[0027] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations within the meaning and scope of the equivalent elements of the claims be included in the invention. Any marking in a claim should not be considered as limiting the claim to which it relates.

Claims

1. A method for removing calcium and magnesium from cobalt nickel hydroxide raw materials, characterized in that: The method comprises the following preparation steps: (1) Take 50g of cobalt nickel hydroxide raw material, add 250-400mL of deionized water, maintain the temperature at 10-50°C, maintain the carbon dioxide pressure at 0.30-0.65MPa, stir at 240-650rpm for 30-60min, filter out the water-soluble calcium and magnesium solution, and send the nickel-cobalt filter residue to the next step of purification; (2) According to the residual calcium and magnesium content in the residue, add 1-2g of solid ferrous sulfate; adjust the pH to 5 with dilute sulfuric acid, react for 2-8h, separate the solid and liquid to obtain filtrate and residue, and wash the residue with water spray; put the washed residue into a drying oven to dry to obtain a secondary impurity-removed residue; (3) Three times of impurity removal: acidify the filter residue from the second impurity removal with sulfuric acid-ammonium phosphate in a volume ratio of 1:0.5-1.5, control the temperature at 65-80°C, and leach for 1-2.5 hours, then add deionized water 2-3 times the weight of the filter residue from the first impurity removal, and leach for 1-2 hours to obtain an intermediate product solution; add ammonia water to adjust the pH to 5.5 and react for 1-4.0 hours. After the reaction is completed, filter out the calcium phosphate / ammonium magnesium precipitate under a negative pressure of -0.075 MPa to obtain a purified nickel-cobalt solution, and filter out the precipitate under negative pressure for 4-6 hours. After the reaction is completed, filter out the precipitate to obtain the final impurity-removed raw material solution.

2. The method for removing calcium and magnesium from a cobalt nickel hydroxide raw material according to claim 1, characterized in that: The proportion of the raw material components of cobalt nickel hydroxide in step (1) is: 3.13% Co, 37.13% Ni, 0.12% Cu, 0.37% Fe, 5.23% Mn, 0.52% Zn, 0.011% Ca, 6.57% Mg, 0.41% Na, 0.0011% Cd, and 0.0099% Cr.

3. The method for removing calcium and magnesium from a cobalt nickel hydroxide raw material according to claim 1, characterized in that: The concentration of dilute sulfuric acid in step (2) is 25-50wt%.

4. The method for removing calcium and magnesium from a cobalt nickel hydroxide raw material according to claim 1, characterized in that: In the step (2), the liquid-to-solid ratio of the spray washing water to the filter residue is 5:

1.

5. The method for removing calcium and magnesium from a cobalt nickel hydroxide raw material according to claim 1, characterized in that: In step (2), the mixture is dried in a drying oven at 80° C. for 2 h.

6. The method for removing calcium and magnesium from a cobalt-nickel hydroxide raw material according to claim 1, characterized in that: The concentration of sulfuric acid in step (3) is 85%.

7. The method for removing calcium and magnesium from a cobalt nickel hydroxide raw material according to claim 1, characterized in that: The concentration of ammonium phosphate in step (3) is 15%.

8. The method for removing calcium and magnesium from a cobalt-nickel hydroxide raw material according to claim 1, characterized in that: The concentration of ammonia water in step (3) is 0.01 mol / L.

9. The method for removing calcium and magnesium from a cobalt nickel hydroxide raw material according to claim 1, characterized in that: The negative pressure filtration pressure in step (3) is -0.075 MPa.

10. The method for removing calcium and magnesium from a cobalt nickel hydroxide raw material according to claim 1, characterized in that: The filtration temperature in step (3) is 65-80°C.

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