Method for improving filtering performance in leaching process of crude cobalt nickel hydroxide

Abstract

The invention discloses a method for improving the filtering performance in the leaching process of crude cobalt nickel hydroxide. The method comprises the following steps: mixing the crude cobalt nickel hydroxide with water to prepare first ore pulp and second ore pulp, and emulsifying; carrying out first high acid leaching on the emulsified first ore pulp, preserving heat and filtering to obtain first filtrate; adding emulsified second ore pulp into the first filtrate to carry out primary iron and aluminum removal, and carrying out heat preservation and filtration to obtain second filter residues and second filtrate; taking a part of the second filter residue for acid curing leaching, and filtering to obtain a third filter residue and a third filtrate; mixing the third filtrate with the third filter residue to obtain a material B; mixing the residual second filter residue with the second filtrate to obtain a material A; leaching the material A and the material B with a second high acid, preserving heat and filtering to obtain a fourth filtrate and a fourth filter residue; and the emulsified second ore pulp is added into the fourth filtrate for secondary iron and aluminum removal, nickel-cobalt rich liquor is obtained after filtering, the problem that filtering is difficult in the nickel-cobalt valuable metal element leaching process is effectively solved, and efficient liquid-solid separation is achieved.

Description

Technical Field

[0001] This invention belongs to the field of non-ferrous metal hydrometallurgy technology, and specifically relates to a method for improving the filtration performance during the leaching of crude nickel-cobalt hydroxide. Background Technology

[0002] Nickel sulfate is a crucial raw material for battery materials. It can be used to produce precursor materials for ternary batteries such as nickel-cobalt-manganese and nickel-cobalt-aluminum, as well as cathode materials for nickel-metal hydride and nickel-cadmium rechargeable batteries. With the development of aluminum profile surface treatment technology and the upgrading of battery products, the application fields of nickel sulfate are constantly expanding. As one of the main raw materials for ternary batteries, the market demand for nickel sulfate is increasing year by year. In recent years, with the rapid development of the power lithium battery industry, more and more projects are inclined to produce easier-to-process nickel-cobalt hydroxide (MHP) products, whose main products are nickel sulfate and cobalt sulfate. Currently, the mainstream process for preparing battery-grade nickel sulfate from MHP is leaching-iron removal-extraction purification. This method has stable raw materials and a short reaction time, but the leaching process is difficult to filter, resulting in low production efficiency and high energy consumption.

[0003] To improve the filtration performance of the nickel-cobalt hydroxide leaching process, patent CN117083402A discloses a method for desiliconization and silicon reuse during the nickel-cobalt hydroxide leaching process. This method involves leaching nickel-cobalt hydroxide using low acid and high pressure, followed by filtration to obtain a first filter residue and a first filtrate. This invention transforms difficult-to-filter silicic acid into easily filterable silicon dioxide by converting it under high temperature and pressure, significantly improving the filtration performance of silicon impurity precipitation and thus solving the problem of this step causing bottlenecks in the entire production process. However, this method requires leaching under high pressure, placing high demands on production equipment and potentially posing safety hazards. Summary of the Invention

[0004] The main objective of this invention is to provide a method for improving the filtration performance during the leaching process of crude nickel-cobalt hydroxide, thereby solving the technical problems of difficult filtration, low production efficiency, high energy consumption, and poor safety due to the need for high-pressure leaching in the existing crude nickel-cobalt hydroxide leaching process.

[0005] To achieve the above objectives, the present invention provides a method for improving the filtration performance during the leaching process of crude nickel-cobalt hydroxide, comprising the following steps: Step S1: Mix crude nickel-cobalt hydroxide with water to prepare a first slurry and a second slurry, and then emulsify the first slurry and the second slurry. Step S2: The emulsified first slurry is mixed with acid solution for a first high acid leaching, and the material after the first high acid leaching is subjected to a first heat preservation filtration to obtain a first filtrate and a first filter residue. Step S3: Air is introduced into the first filtrate, and the emulsified second slurry is added to carry out the first iron and aluminum removal reaction. Step S4: The material after the reaction in step S3 is subjected to a second heat preservation filtration to obtain a second filter residue and a second filtrate. A portion of the second filter residue is mixed with acid solution for aging and leaching. The remaining second filter residue and the second filtrate are mixed to obtain a solid-liquid mixture A for later use. Step S5: Filter the material after aging and leaching in step S4 to obtain the third filter residue and the third filter liquid. Take the third filter liquid and mix it with the third filter residue in a certain proportion to obtain solid-liquid mixture B for later use. Step S6: Mix the solid-liquid mixture A and the solid-liquid mixture B with acid solution for a second high-acid leaching, and then perform a third heat preservation filtration on the material after the second high-acid leaching to obtain a fourth filtrate and a fourth filter residue. Step S7: Air is introduced into the fourth filtrate, and the emulsified second slurry is added to carry out a second iron and aluminum removal reaction. After the reaction is completed, the solution is filtered to obtain a nickel-cobalt rich solution.

[0006] Furthermore, the mass concentration of the first slurry is 10-40%.

[0007] Furthermore, the mass concentration of the second slurry is 20-50%.

[0008] Furthermore, the reaction temperature for the first high-acid leaching is 80~95℃, and the reaction time is 2~7h.

[0009] Furthermore, the mass ratio of the acid solution from the first high-acid leaching to the first slurry is 1:4~6.

[0010] Furthermore, the first high-acid leaching is carried out under stirring conditions, with a stirring speed of 300~800 r / min.

[0011] Further, in step S3, the mass ratio of the first filtrate to the second slurry is 1:1~3.

[0012] Furthermore, in step S3, the pH value of the first iron and aluminum removal reaction is 4.0~7.0, the reaction temperature is 75~90℃, the reaction time is 3~6h, and the air flow rate is 1~5L / min.

[0013] Furthermore, in step S3, the reaction is carried out under stirring conditions at a speed of 300-600 r / min.

[0014] Further, in step S3, the emulsified second slurry is added to the first iron and aluminum removed liquid within 10 to 90 minutes.

[0015] Furthermore, in step S4, the reaction temperature for the aging leaching is 85~95℃, and the reaction time is 2~7h.

[0016] Further, in step S4, the mass ratio of the acid solution in the aging leaching to the second filter residue is 1:1.5~3.5.

[0017] Furthermore, the aging and leaching process is carried out under stirring conditions, with a stirring speed of 300~800 r / min.

[0018] Furthermore, during the aging and leaching process, the second filter residue is slowly added over a period of 30 to 90 minutes.

[0019] Furthermore, the solid-liquid mixture A has a solid-liquid ratio of 1:2 to 5.

[0020] Furthermore, the solid-liquid mixture B has a solid-liquid ratio of 1:2 to 5.

[0021] Furthermore, in step S6, the reaction temperature of the second high-acid leaching is 80~95℃, and the reaction time is 2~7h.

[0022] Furthermore, in the second high-acid leaching process, the mass ratio of the acid solution to the total of the solid-liquid mixture A and the solid-liquid mixture B is 1:4~6.

[0023] Furthermore, the second high-acid leaching is carried out under stirring conditions, with a stirring speed of 300~800 r / min.

[0024] Furthermore, during the second high-acid leaching process, solid-liquid mixture A and solid-liquid mixture B are slowly added over a period of 30 to 90 minutes.

[0025] Furthermore, the temperature of the first thermal insulation filter is 40~80℃.

[0026] Furthermore, the temperature of the second thermal insulation filter is 40~60℃.

[0027] Furthermore, the temperature of the third heat-insulating filter is 40~80℃.

[0028] Furthermore, in step S7, the pH value of the second iron and aluminum removal reaction is 4.0~7.0, the reaction temperature is 75~90℃, the reaction time is 3~6h, and the air flow rate is 1~5L / min.

[0029] Further, in step S7, the mass ratio of the fourth filtrate to the second slurry is 1:1~3.

[0030] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention mainly includes step-by-step leaching, segmented iron and aluminum removal, and intermediate slag recycling steps. It effectively solves the problem of difficult filtration in the crude nickel-cobalt hydroxide leaching process by aging leaching, segmented iron and aluminum removal, and multi-stage heat preservation filtration. It has excellent filtration performance, does not require high-pressure leaching, has low requirements for production equipment, and is highly safe.

[0031] 2. The method of the present invention can efficiently extract valuable nickel and cobalt metal elements from crude nickel-cobalt hydroxide. Compared with the prior art, it does not require the addition of additional reducing agents or other nickel matte raw materials, avoids the introduction of impurities into the system, greatly reduces production costs, and has simple process conditions and is easy to operate. Attached Figure Description

[0032] Figure 1 A schematic flowchart of the method for improving filtration performance during the leaching of crude nickel-cobalt hydroxide according to the present invention is shown. Detailed Implementation

[0033] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. Furthermore, regarding the numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included within this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range. The invention will now be described in detail with reference to embodiments.

[0034] To achieve the above objectives, embodiments of the present invention provide a method for improving the filtration performance during the leaching process of crude nickel-cobalt hydroxide, such as... Figure 1 As shown, the following steps are included: Step S1: Mix crude nickel-cobalt hydroxide with water to prepare a first slurry and a second slurry, and then emulsify the first slurry and the second slurry respectively; Step S2: The emulsified first slurry is mixed with acid solution for a first high acid leaching, and the material after the first high acid leaching is subjected to a first heat preservation filtration to obtain a first filtrate and a first filter residue. Step S3: After the first filtrate is subjected to the first iron and aluminum removal treatment, the first iron and aluminum removed liquid is obtained. Then, air is introduced into the first iron and aluminum removed liquid, and the emulsified second slurry is added to react. Step S4: The material after the reaction in step S3 is subjected to a second heat preservation filtration to obtain a second filter residue and a second filtrate. A portion of the second filter residue is mixed with acid solution for aging and leaching. The remaining second filter residue and the second filtrate are mixed to obtain a solid-liquid mixture A for later use. Step S5: The material after aging and leaching in step S4 is subjected to a third heat preservation filtration to obtain a third filter residue and a third filter liquid. The third filter liquid is mixed with the third filter residue in a certain proportion to obtain a solid-liquid mixture B for later use. Step S6: Mix the solid-liquid mixture A and the solid-liquid mixture B with acid solution for a second high-acid leaching, and then perform a third heat preservation filtration on the material after the second high-acid leaching to obtain a fourth filtrate and a fourth filter residue. Step S7: Air is introduced into the fourth filtrate, and the emulsified second slurry is added to carry out a second iron and aluminum removal reaction. After the reaction is completed, the solution is filtered to obtain a nickel-cobalt rich solution.

[0035] This invention employs a staged iron and aluminum removal process for crude nickel-cobalt hydroxide. First, a second, emulsified slurry is added to the high-acid leaching solution from a first high-acid leaching process to remove iron and aluminum, generating a second filter residue that is easily filtered. This second filter residue is then graded. A portion of the second filter residue (generally 20%–70% of the total) undergoes aging leaching to further dissolve fine particles, promote the recovery of residual nickel and cobalt metals, and improve filterability. Another portion of the second filter residue is directly mixed with the second filtrate as seed crystals to improve the precipitation of impurities in the subsequent solid-liquid mixture A. This grading process reduces the processing volume while still effectively improving filtration performance. The third filtrate after aging leaching is mixed with the third filter residue in a specific ratio to maintain the ionic strength of the system and promote subsequent precipitation, yielding a solid-liquid mixture B. Then, solid-liquid mixtures A and B undergo a second-stage iron and aluminum removal process to improve the extraction rate of valuable nickel and cobalt metals and the removal rate of iron and aluminum impurities in the crude nickel-cobalt hydroxide. This invention, through the aforementioned segmented iron and aluminum removal process, avoids precipitation load and improves the crystallinity of iron and aluminum precipitates, preventing the formation of colloids such as aluminum hydroxide (Al(OH)3), Fe(OH)3, and silica gel, thereby effectively improving filtration performance. Simultaneously, this invention, through multi-stage heat-insulated filtration, can reduce filtrate viscosity and improve filter cake characteristics. For impurities in the residue that easily form colloids, such as aluminum hydroxide (Al(OH)3), Fe(OH)3, and silica gel, heat-insulated filtration promotes their transformation into a more crystalline and denser structure, helping to improve filtration efficiency and prevent pipe blockage.

[0036] In an embodiment of the present invention, the crude nickel-cobalt hydroxide contains 37-40% nickel, 3-5% cobalt, 4-7% manganese, 0.01-0.05% iron, 0.10-0.30% aluminum, 0.50-0.80% zinc, and 0.15-0.30% copper.

[0037] In a preferred embodiment of the present invention, the mass concentration of the first slurry is 10-40%, for example, 10%, 15%, 20%, 25%, 30%, 35%, or 40%. The mass concentration of the second slurry is 20-50%, for example, 20%, 25%, 30%, 35%, 40%, 45%, or 50%. The present invention, by controlling the concentration of the second slurry, ensures that the second slurry fully reacts with the leaching filtrate during the iron and aluminum removal reaction. The hydroxide ions in the second slurry neutralize, hydrolyze, and precipitate with the iron and aluminum ions in the leaching filtrate, effectively removing impurities such as iron and aluminum from the leaching filtrate. The present invention utilizes the alkaline substances (hydroxides) inherent in the crude nickel-cobalt hydroxide raw material as a neutralizing agent, offering advantages such as low cost, reduced external reagent addition, and resource utilization.

[0038] To further ensure the efficient leaching rate of nickel and cobalt elements in the first slurry and the specific morphology of ions in the filter residue, avoiding the formation of silica colloids, Al(OH)3, Fe(OH)3, etc., and giving the ions a good crystal structure to improve filtration performance, in some preferred embodiments of the present invention, the reaction temperature of the first high-acid leaching is 80~95℃, preferably 85~90℃, and the reaction time is 2~7h, preferably 3~6h. The mass ratio of the acid solution to the first slurry in the first high-acid leaching is 1:4~6. By controlling the mass ratio of the acid solution to the first slurry in the first high-acid leaching, the acidity of the solution after the first high-acid leaching is made to be 30~50g / l, inhibiting the formation of colloids. The acid solution can be, for example, a sulfuric acid solution with a mass fraction of 80~98%. The first high-acid leaching is carried out under stirring conditions, with a stirring speed of 300~800r / min, preferably 400~700r / min.

[0039] To further ensure the efficient leaching rate of nickel and cobalt elements in the first slurry and the specific morphology of ions in the filter residue, avoiding the formation of silica globules, Al(OH)3, Fe(OH)3, etc., and giving the ions a good crystal structure to improve filtration performance, in some preferred embodiments of the present invention, in step S3, the mass ratio of the first filtrate to the second slurry is 1:1~3. The pH value of the reaction is 4.0~7.0, preferably 4.6~5.7, the reaction temperature is 75~90℃, preferably 75~85℃, and the reaction time is 3~6h, preferably 4~5h. The reaction is carried out under stirring conditions, with a stirring speed of 300~600r / min, preferably 350~500r / min. The emulsified second slurry is added to the first filtrate within 10~90min, preferably 30~60min. By controlling the addition rate of the emulsified second slurry, it is slowly and evenly added to the first filtrate to allow for a thorough reaction.

[0040] To further ensure the efficient leaching rate of nickel and cobalt elements in the first slurry and the specific morphology of ions in the filter residue, avoiding the formation of silica colloids, Al(OH)3, Fe(OH)3, etc., and giving the ions a good crystal structure to improve filtration performance, in some preferred embodiments of the present invention, the reaction temperature of the aging leaching is 85~95℃, and the reaction time is 2~7h. The mass ratio of the acid solution to the second filter residue in the aging leaching is 1:1.5~3.5. By controlling the mass ratio of the acid solution to the second filter residue in the aging leaching, the acidity of the solution after aging acid leaching is made to be 30~50g / l, inhibiting the formation of colloids. The acid solution can be, for example, a sulfuric acid solution with a mass fraction of 80~98%. The aging leaching process is carried out under stirring conditions at a stirring speed of 300~800r / min. The second filter residue is slowly added during the aging leaching process over a time of 30~90min.

[0041] In some preferred embodiments of the present invention, in step S4, a portion of the second filter residue is mixed with acid solution for aging and leaching, wherein the portion of the second filter residue accounts for 15-30% of the total mass of the second filter residue. The solid-liquid ratio of the solid-liquid mixture A is 1:2-5. In step S5, the solid-liquid ratio of the solid-liquid mixture B is 1:2-5. By controlling the solid-liquid ratio of solid-liquid mixture A and solid-liquid mixture B, the present invention can reasonably control the amount of the second-stage iron and aluminum removal reaction, maintaining the ion content within a suitable range without affecting appropriate process parameters, thereby improving its filterability.

[0042] In some preferred embodiments of the present invention, in step S6, the reaction temperature of the second high-acid leaching is 80-95°C, preferably 85-90°C, and the reaction time is 2-7 hours, preferably 3-6 hours. The mass ratio of the acid solution to the total of solid-liquid mixture A and solid-liquid mixture B in the second high-acid leaching is 1:4-6. By controlling the mass ratio of the acid solution to the total of solid-liquid mixture A and solid-liquid mixture B in the second high-acid leaching, the acidity of the solution after the second high-acid leaching is made 30-50 g / L, thus inhibiting the formation of colloids. The acid solution can be, for example, a sulfuric acid solution with a mass fraction of 80-98%. The second high-acid leaching is carried out under stirring conditions, with a stirring speed of 300-800 r / min, preferably 400-700 r / min; during the second high-acid leaching process, solid-liquid mixture A and solid-liquid mixture B are slowly added over a time of 30-90 minutes.

[0043] To further optimize the filtration performance during the crude nickel-cobalt hydroxide leaching process, in some preferred embodiments of the present invention, the temperature of the first heat-insulating filter is 40~80℃, preferably 50~75℃; the temperature of the second heat-insulating filter is 40~60℃, preferably 45~60℃; and the temperature of the third heat-insulating filter is 40~80℃, preferably 50~75℃.

[0044] In some preferred embodiments of the present invention, in step S7, the pH value of the second iron-aluminum removal reaction is 4.0~7.0, the reaction temperature is 75~90℃, and the reaction time is 3~6h. The air flow rate is 1~5L / min. By precisely controlling the reaction pH value, the present invention can ensure that Fe(OH)3 and Al(OH)3 are almost completely precipitated, while Ni... 2+ and Co 2+ The iron and aluminum are essentially retained in the solution, and efficient removal and good slag filtration performance are ensured by synergistically controlling the reaction temperature and reaction time. Furthermore, the mass ratio of the fourth filtrate to the second slurry is 1:1~3. By controlling the mass ratio of the fourth filtrate to the second slurry, the fourth filtrate and the second slurry can react fully, effectively removing impurities such as iron and aluminum from the solution.

[0045] The present application will be further described in detail below with reference to specific embodiments, which should not be construed as limiting the scope of protection claimed in the present application.

[0046] Example 1 A method for improving the filtration performance during the leaching of crude nickel-cobalt hydroxide includes the following steps: Step S1: Take 900g of crude nickel cobalt hydroxide (MHP) and mix it with water to prepare a first slurry and a second slurry, both with a mass concentration of 20%. Then, emulsify the first and second slurries. The crude nickel cobalt hydroxide contains 38% nickel, 4% cobalt, 5% manganese, 0.03% iron, 0.23% aluminum, 0.62% zinc, and 0.24% copper.

[0047] Step S2: Weigh a 98% concentrated sulfuric acid solution and place it in a reaction vessel. Under conditions of 90℃ and a stirring speed of 600 r / min, add the emulsified first slurry to the reactor for the first high-acid leaching, and react for 5 hours. After the reaction, filter at 70℃. The time required for complete filtration is 0.5 hours, yielding the first filter residue and the first filtrate. The mass ratio of concentrated sulfuric acid solution to the first slurry is 1:5.

[0048] Step S3: Place the first filtrate obtained in step S2 into a reaction vessel, adjust the temperature to 80℃, and introduce air (2L / min) while stirring at 400r / min. Add the emulsified second slurry over 60 minutes to bring the pH of the reaction system to 5.5, and then continue stirring for 5 hours. The mass ratio of the first filtrate to the second slurry is 1:2.

[0049] Step S4: The material after the reaction in step S3 is completely filtered at 55℃ for 0.1 hours to obtain a second filter residue and a second filtrate. 20% of the second filter residue by mass is used for aging and leaching. The remaining second filter residue and second filtrate are mixed to obtain a solid-liquid mixture A (solid-liquid ratio 1:3) for later use. The specific aging and leaching process is as follows: A 98% concentrated sulfuric acid solution is weighed and placed in a reaction vessel. Under conditions of 90℃ and a stirring speed of 600 r / min, 20% of the second filter residue by mass is slowly added to the reactor (wherein the mass ratio of concentrated sulfuric acid solution to second filter residue is 1:5), completed within 20 minutes, and the reaction is stirred for 6 hours.

[0050] Step S5: The material after aging and leaching in step S4 is completely filtered in 0.05 hours to obtain the third filter residue and the third filter liquid. The third filter liquid and all the third filter residue are mixed in proportion to obtain solid-liquid mixture B (solid-liquid ratio of 1:5) for later use.

[0051] Step S6: Weigh a 98% concentrated sulfuric acid solution and place it in a reaction vessel. Under conditions of 90℃ and a stirring speed of 600 r / min, slowly add the above solid-liquid mixture A and solid-liquid mixture B into the reaction vessel. Complete the addition within 30 minutes, and carry out the second high-acid leaching reaction for 5 hours. Then, filter the material after the second high-acid leaching at 70℃. The time required for complete filtration is 0.3 hours, obtaining the fourth filtrate and the fourth filter residue. The mass ratio of concentrated sulfuric acid solution to the total mass of solid-liquid mixture A and solid-liquid mixture B during the second high-acid leaching process is 1:5.

[0052] Step S7: The fourth filtrate is placed in a reaction vessel, the temperature is adjusted to 80℃, and air is introduced (2L / min) while stirring at 400r / min. The emulsified second slurry is added over 60 minutes to bring the pH of the reaction system to 5.5, and the reaction is continued with stirring for 5 hours. The mass ratio of the fourth filtrate to the second slurry is 1:2. The reactants are then completely filtered for 0.1 hours to obtain a nickel-cobalt rich solution. Further purification of the nickel-cobalt rich solution yields battery-grade nickel sulfate and cobalt sulfate, among other pure materials.

[0053] In this embodiment, the nickel recovery rate of the nickel-cobalt rich solution is 99.6%, and the cobalt recovery rate is 98.3%. The total filtration time used to extract the nickel-cobalt rich solution from the crude nickel-cobalt hydroxide in this embodiment is 1.05 hours.

[0054] Example 2 A method for improving the filtration performance during the leaching of crude nickel-cobalt hydroxide differs from Example 1 in that the material after the first high-acid leaching in step S2 and the material after the second high-acid leaching in step S6 of this example are subjected to heat preservation filtration at 50°C. The total filtration time used to extract nickel-cobalt rich solution from crude nickel-cobalt hydroxide in this example is 2.95 hours.

[0055] Example 3 A method for improving the filtration performance during the leaching of crude nickel-cobalt hydroxide differs from Example 1 in that, in step S4 of this example, the material after the first iron-aluminum removal reaction and the material after the second iron-aluminum removal reaction in step S7 are subjected to heat preservation filtration at 45°C. In this example, the total filtration time used to extract nickel-cobalt rich solution from crude nickel-cobalt hydroxide is 1.45 hours.

[0056] Comparative Example 1 A method for improving the filtration performance during the leaching of crude nickel-cobalt hydroxide differs from Example 1 in that, in step S2, the material after the first high-acid leaching is filtered at room temperature (25°C), and the time required to filter all the material is 4 hours; in step S4, the material after the aging leaching is filtered at room temperature (25°C), and the time required to filter all the material is 2 hours; in step S6, the material after the second high-acid leaching is filtered at room temperature (25°C), and the time required to filter all the material is 3 hours; and in step S7, the material after the second iron-aluminum removal reaction is filtered at room temperature (25°C), and the time required to filter all the material is 2 hours. The total filtration time used in this comparative example to extract nickel-cobalt rich solution from crude nickel-cobalt hydroxide is 11.05 hours.

[0057] Comparative Example 2 A method for improving the filtration performance during the leaching of crude nickel-cobalt hydroxide differs from Example 1 in that the comparative example does not include the aging leaching process in step S4, and all filtration stages are performed at room temperature (25°C). The specific process is as follows: Step S1: Take 900g of crude nickel cobalt hydroxide (MHP) and mix it with water to prepare a first slurry and a second slurry, both with a mass concentration of 20%. Then, emulsify the first and second slurries. The crude nickel cobalt hydroxide contains 38% nickel, 4% cobalt, 5% manganese, 0.03% iron, 0.23% aluminum, 0.62% zinc, and 0.24% copper.

[0058] Step S2: Weigh a 98% concentrated sulfuric acid solution and place it in a reaction vessel. Under conditions of 90℃ and a stirring speed of 600 r / min, add the emulsified first slurry to the reactor for the first high-acid leaching, and react for 5 hours. After the reaction, filter at room temperature. The time required for complete filtration is 4 hours, yielding the first filter residue and the first filtrate. The mass ratio of concentrated sulfuric acid solution to the first slurry is 1:5.

[0059] Step S3: Place the first filtrate obtained in step S2 into a reaction vessel, adjust the temperature to 80℃, and introduce air (2L / min) while stirring at 400r / min. Add the emulsified second slurry over 60 minutes to bring the pH of the reaction system to 5.5, and then continue stirring for 5 hours. The mass ratio of the first filtrate to the second slurry is 1:2.

[0060] Step S4: The material after the reaction in step S3 is filtered at room temperature. The time required for complete filtration is 2 hours, resulting in the second filter residue and the second filtrate.

[0061] Step S5: Weigh a 98% concentrated sulfuric acid solution and place it in a reaction vessel. Under conditions of 90℃ and a stirring speed of 600 r / min, slowly add the second filter residue and the second filtrate from step S4 into the reaction vessel. Complete the addition within 30 minutes, and carry out the second high-acid leaching reaction for 5 hours. Then, filter the material after the second high-acid leaching at room temperature. The time required for complete filtration is 6 hours, yielding the third filtrate. The mass ratio of the concentrated sulfuric acid solution to the total mass of the second filter residue and the second filtrate during the second high-acid leaching process is 1:5.

[0062] Step S6: The third filtrate is placed in a reaction vessel, the temperature is adjusted to 80℃, and air is introduced (2L / min) while stirring at 400r / min. The emulsified second slurry is added over 60 minutes to bring the pH of the reaction system to 5.5, and the reaction is continued with stirring for 5 hours. The mass ratio of the third filtrate to the second slurry is 1:2. The reacted material is then filtered at room temperature, with complete filtration taking 2 hours, yielding a nickel-cobalt rich solution. This solution is further purified to obtain battery-grade nickel sulfate and cobalt sulfate, among other pure materials.

[0063] In this comparative example, the nickel-cobalt rich solution obtained had a nickel recovery rate of 99.7% and a cobalt recovery rate of 98.6%. The total filtration time used in this comparative example to extract the nickel-cobalt rich solution from crude nickel-cobalt hydroxide was 14 hours.

[0064] The embodiments described above are merely illustrative of implementation methods of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. The present invention can also be implemented in other specific ways or forms without departing from its spirit or essential characteristics. Therefore, the described embodiments should be considered illustrative rather than limiting in any respect. The scope of the present invention should be defined by the appended claims, and any variations equivalent to the intent and scope of the claims should also be included within the scope of the present invention.

Claims

1. A method for improving the filtration performance during the leaching of crude nickel-cobalt hydroxide, characterized in that, Includes the following steps: Step S1: Mix crude nickel-cobalt hydroxide with water to prepare a first slurry and a second slurry, and then emulsify the first slurry and the second slurry. Step S2: The emulsified first slurry is mixed with acid solution for a first high acid leaching, and the material after the first high acid leaching is subjected to a first heat preservation filtration to obtain a first filtrate and a first filter residue. Step S3: Air is introduced into the first filtrate, and the emulsified second slurry is added to carry out the first iron and aluminum removal reaction. Step S4: The material after the reaction in step S3 is subjected to a second heat preservation filtration to obtain a second filter residue and a second filtrate. A portion of the second filter residue is mixed with acid solution for aging and leaching. The remaining second filter residue and the second filtrate are mixed to obtain a solid-liquid mixture A for later use. Step S5: Filter the material after aging and leaching in step S4 to obtain the third filter residue and the third filter liquid. Take the third filter liquid and mix it with the third filter residue in a certain proportion to obtain solid-liquid mixture B for later use. Step S6: Mix the solid-liquid mixture A and the solid-liquid mixture B with acid solution for a second high-acid leaching, and then perform a third heat preservation filtration on the material after the second high-acid leaching to obtain a fourth filtrate and a fourth filter residue. Step S7: Air is introduced into the fourth filtrate, and the emulsified second slurry is added to carry out a second iron and aluminum removal reaction. After the reaction is completed, the solution is filtered to obtain a nickel-cobalt rich solution.

2. The method for improving the filtration performance during the leaching process of crude nickel-cobalt hydroxide according to claim 1, characterized in that, In step S1, the mass concentration of the first slurry is 10-40%; and / or, the mass concentration of the second slurry is 20-50%.

3. The method for improving the filtration performance during the leaching process of crude nickel-cobalt hydroxide according to claim 1, characterized in that, In step S2, the reaction temperature of the first high acid leaching is 80~95℃, and the reaction time is 2~7h; And / or, the mass ratio of the acid solution from the first high-acid leaching to the first slurry is 1:4~6.

4. The method for improving the filtration performance during the leaching process of crude nickel-cobalt hydroxide according to claim 1, characterized in that, In step S3, the mass ratio of the first filtrate to the second slurry is 1:1~3; And / or, in step S3, the pH value of the first iron and aluminum removal reaction is 4.0~7.0, the reaction temperature is 75~90℃, the reaction time is 3~6h, and the air flow rate is 1~5L / min; And / or, in step S3, the emulsified second slurry is added to the first filtrate within 10 to 90 minutes.

5. The method for improving the filtration performance during the leaching process of crude nickel-cobalt hydroxide according to claim 1, characterized in that, In step S4, the reaction temperature for the aging leaching is 85~95℃, and the reaction time is 2~7h.

6. The method for improving the filtration performance during the leaching process of crude nickel-cobalt hydroxide according to claim 1, characterized in that, In step S4, the mass ratio of the acid solution in the aging leaching to the second filter residue is 1:1.5~3.5; And / or, during the aging and leaching process, the second filter residue is slowly added over a period of 30 to 90 minutes.

7. The method for improving the filtration performance during the leaching process of crude nickel-cobalt hydroxide according to claim 1, characterized in that, The solid-liquid mixture A has a solid-liquid ratio of 1:2 to 5; and / or, the solid-liquid mixture B has a solid-liquid ratio of 1:2 to 5.

8. The method for improving the filtration performance during the leaching process of crude nickel-cobalt hydroxide according to claim 1, characterized in that, In step S6, the reaction temperature of the second high acid leaching is 80~95℃, and the reaction time is 2~7h; And / or, in the second high-acid leaching, the mass ratio of the acid solution to the total of solid-liquid mixture A and solid-liquid mixture B is 1:4~6; And / or, during the second high-acid leaching process, solid-liquid mixture A and solid-liquid mixture B are slowly added over a period of 30 to 90 minutes.

9. The method for improving the filtration performance during the leaching process of crude nickel-cobalt hydroxide according to claim 1, characterized in that, The temperature of the first thermal insulation filter is 40~80℃; the temperature of the second thermal insulation filter is 40~60℃; and the temperature of the third thermal insulation filter is 40~80℃.

10. The method for improving the filtration performance during the leaching process of crude nickel-cobalt hydroxide according to claim 1, characterized in that, In step S7, the pH value of the second iron and aluminum removal reaction is 4.0~7.0, the reaction temperature is 75~90℃, the reaction time is 3~6h, and the air flow rate is 1~5L / min. And / or, the mass ratio of the fourth filtrate to the second slurry is 1:1~3.

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