A method for improving the filtration performance in the leaching process of crude nickel-cobalt hydroxide

Abstract

The application discloses a method for improving filtering performance in a crude nickel-cobalt hydroxide leaching process, which comprises the following steps: mixing the crude nickel-cobalt hydroxide with water to prepare a first ore pulp, a second ore pulp and emulsification; performing first high-acid leaching on the emulsified first ore pulp, heat preservation and filtration to obtain a first filtrate; adding the emulsified second ore pulp to the first filtrate to perform primary iron and aluminum removal, heat preservation and filtration to obtain second filtration residue and second filtrate; taking part of the second filtration residue to perform acid curing leaching, and after filtration, third filtration residue and third filtrate are obtained; mixing the third filtrate with the third filtration residue to obtain material B; mixing the remaining second filtration residue with the second filtrate to obtain material A; performing second high-acid leaching on the material A and the material B, heat preservation and filtration to obtain fourth filtrate and fourth filtration residue; adding the emulsified second ore pulp to the fourth filtrate to perform secondary iron and aluminum removal, and after filtration, a nickel-cobalt rich solution is obtained, effectively solving the problem of difficult filtration in the nickel-cobalt valuable metal element leaching process, and realizing efficient separation of liquid and solid.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of non-ferrous hydrometallurgy, and particularly relates to a method for improving the filtration performance in the leaching process of crude nickel-cobalt hydroxide. BACKGROUND

[0002] Nickel sulfate is the most important raw material for battery materials, that is, it can be used to produce precursor materials for ternary batteries such as nickel-cobalt-manganese, nickel-cobalt-aluminum, and is also used to produce positive electrode materials for nickel-hydrogen and nickel-cadmium secondary batteries. With the development of surface treatment process of aluminum profiles and the upgrading of battery products, the application field of nickel sulfate is continuously 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 tend to produce nickel-cobalt hydroxide (MHP) products which are easier to handle, and the main products are nickel sulfate and cobalt sulfate. At present, the mainstream process for preparing battery-grade nickel sulfate from MHP is leaching-iron removal-impurity removal by extraction. This method has stable raw materials and short reaction time, but there are problems such as low production efficiency, high energy consumption and the like in the leaching process due to the difficulty in filtration.

[0003] In order to improve the filtration performance in the leaching process of nickel-cobalt hydroxide, patent CN117083402A discloses a method for desiliconization and silicon recycling in the leaching process of nickel-cobalt hydroxide. In this method, nickel-cobalt hydroxide is leached by low-acid high-pressure leaching to obtain first filter residue and first filtrate. In this invention, silicon dioxide is converted from silicic acid at high temperature and high pressure, so that the silicic acid which is difficult to filter is transformed into silicon dioxide which is easy to filter, and the filtration performance of the precipitated impurity silicon is greatly improved, thereby solving the problem that this process causes a jam in the entire production process. However, this method requires leaching under high pressure conditions, which has high requirements for production equipment and is prone to safety hazards. SUMMARY

[0004] The main purpose of the present application is to provide a method for improving the filtration performance in the leaching process of crude nickel-cobalt hydroxide, which solves the technical problems of difficulty in filtration in the leaching process of crude nickel-cobalt hydroxide, low production efficiency, high energy consumption, poor safety due to the use of high-pressure leaching, and the like.

[0005] In order to achieve the above-mentioned purpose, the present application provides a method for improving the filtration performance in the leaching process of crude nickel-cobalt hydroxide, comprising the following steps:

[0006] Step S1, mixing crude nickel-cobalt hydroxide with water to prepare a first ore slurry and a second ore slurry, and then emulsifying the first ore slurry and the second ore slurry;

[0007] Step S2, mixing the emulsified first ore slurry with acid liquor to perform first high-acid leaching, and then performing first heat preservation filtration on the material after the first high-acid leaching to obtain first filtrate and first filter residue;

[0008] Step S3, air is introduced into the first filtrate, and the second ore slurry after emulsification is added to carry out the first iron and aluminum removal reaction;

[0009] Step S4, the material after the reaction in step S3 is subjected to second heat preservation filtration to obtain second filtration residue and second filtrate, part of the second filtration residue is mixed with acid liquid to carry out aging leaching, and the remaining second filtration residue and second filtrate are mixed to obtain solid-liquid mixture A for standby;

[0010] Step S5, the material after the aging leaching in step S4 is subjected to filtration to obtain third filtration residue and third filtrate, and the third filtrate is mixed with the third filtration residue in proportion to obtain solid-liquid mixture B for standby;

[0011] Step S6, the solid-liquid mixture A, the solid-liquid mixture B and acid liquid are mixed to carry out second high-acid leaching, and then the material after the second high-acid leaching is subjected to third heat preservation filtration to obtain fourth filtrate and fourth filtration residue;

[0012] Step S7, air is introduced into the fourth filtrate, and the second ore slurry after emulsification is added to carry out the second iron and aluminum removal reaction, and after the reaction, filtration is carried out to obtain a nickel-cobalt rich liquid.

[0013] Further, the mass concentration of the first ore slurry is 10-40%.

[0014] Further, the mass concentration of the second ore slurry is 20-50%.

[0015] Further, the reaction temperature of the first high-acid leaching is 80-95℃, and the reaction time is 2-7h.

[0016] Further, the mass ratio of the acid liquid to the first ore slurry in the first high-acid leaching is 1:4-6.

[0017] Further, the first high-acid leaching is carried out under stirring, and the stirring speed is 300-800r / min.

[0018] Further, in step S3, the mass ratio of the first filtrate to the second ore slurry is 1:1-3.

[0019] Further, 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 introduction amount is 1-5L / min.

[0020] Further, in step S3, the reaction is carried out under stirring, and the stirring speed is 300-600r / min.

[0021] Further, in step S3, the emulsified second slurry is added to the first iron and aluminum removal solution in 10-90 min.

[0022] Further, in step S4, the reaction temperature of the aging leaching is 85-95℃, and the reaction time is 2-7 h.

[0023] Further, in step S4, the mass ratio of the acid solution to the second filter residue in the aging leaching is 1:1.5-3.5.

[0024] Further, the aging leaching process is carried out under stirring at a stirring speed of 300-800 r / min.

[0025] Further, the second filter residue is slowly added in the aging leaching process, and the feeding time is 30-90 min.

[0026] Further, the solid-liquid ratio of the solid-liquid mixture A is 1:2-5.

[0027] Further, the solid-liquid ratio of the solid-liquid mixture B is 1:2-5.

[0028] Further, in step S6, the reaction temperature of the second high-acid leaching is 80-95℃, and the reaction time is 2-7 h.

[0029] Further, in the second high-acid leaching, the mass ratio of the acid solution to the sum of the solid-liquid mixture A and the solid-liquid mixture B is 1:4-6.

[0030] Further, the second high-acid leaching is carried out under stirring at a stirring speed of 300-800 r / min.

[0031] Further, the solid-liquid mixture A and the solid-liquid mixture B are slowly added in the second high-acid leaching process, and the feeding time is 30-90 min.

[0032] Further, the temperature of the first holding filtration is 40-80℃.

[0033] Further, the temperature of the second holding filtration is 40-60℃.

[0034] Further, the temperature of the third holding filtration is 40-80℃.

[0035] Further, 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 3-6 h, and the air input amount is 1-5 L / min.

[0036] Further, in step S7, the mass ratio of the fourth filtrate to the second ore slurry is 1:1-3.

[0037] Compared with the prior art, the present application has the following beneficial effects:

[0038] 1. The present application mainly includes steps of step-by-step leaching, step-by-step iron and aluminum removal, and intermediate slag recycling, and effectively solves the problem of difficult filtration in the crude nickel-cobalt hydroxide leaching process through ripening leaching, step-by-step iron and aluminum removal, and multi-stage heat preservation filtration, and has excellent filtration performance, does not need to use high-pressure leaching, has low requirements on production equipment, and is high in safety.

[0039] 2. The method of the present application can efficiently extract nickel and cobalt valuable metal elements from crude nickel-cobalt hydroxide, does not need to add additional reducing agents or other nickel matte raw materials compared with the prior art, avoids the introduction of impurities in the system, greatly reduces the production cost, and has simple process conditions and easy operation. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 A method flow diagram for improving the filtration performance in the crude nickel-cobalt hydroxide leaching process of the present application is shown. DETAILED DESCRIPTION

[0041] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. In addition, for the numerical range in the present application, it should be understood that each intermediate value between the upper limit and the lower limit of the range is also specifically disclosed. Each smaller range between any stated value or intermediate value in the range and any other stated value or intermediate value in the range is also included in the present application. The upper limit and the lower limit of these smaller ranges can be independently included or excluded from the range. The present application will be described in detail below with reference to the embodiments.

[0042] In order to achieve the above-mentioned purpose, the embodiments of the present application provide a method for improving the filtration performance in the crude nickel-cobalt hydroxide leaching process, as shown in Figure 1 The method comprises the following steps:

[0043] Step S1, crude nickel-cobalt hydroxide is mixed with water to prepare first ore slurry and second ore slurry, respectively, and then the first ore slurry and the second ore slurry are emulsified, respectively;

[0044] Step S2, the emulsified first ore slurry is mixed with acid liquor for first high-acid leaching, and then the first high-acid leached material is subjected to first heat preservation filtration to obtain first filtrate and first filter residue;

[0045] Step S3, the first filtrate is subjected to first iron and aluminum removal treatment to obtain first iron and aluminum removal liquid, air is introduced into the first iron and aluminum removal liquid, and the emulsified second ore slurry is added for reaction;

[0046] Step S4, the material after the reaction of step S3 is subjected to second heat preservation filtration to obtain second filtration residue and second filtrate, part of the second filtration residue is mixed with acid liquid for maturation leaching, and the remaining second filtration residue and second filtrate are mixed to obtain a solid-liquid mixture A for standby;

[0047] Step S5, the material after maturation leaching in step S4 is subjected to third heat preservation filtration to obtain third filtration residue and third filtrate, and the third filtrate is mixed with the third filtration residue in proportion to obtain a solid-liquid mixture B for standby;

[0048] Step S6, the solid-liquid mixture A, the solid-liquid mixture B and acid liquid are mixed for second high-acid leaching, and then the material after the second high-acid leaching is subjected to third heat preservation filtration to obtain fourth filtrate and fourth filtration residue;

[0049] Step S7, air is introduced into the fourth filtrate, and emulsified second ore slurry is added for second iron and aluminum removal reaction, and after the reaction is completed, filtration is performed to obtain a nickel-cobalt rich solution.

[0050] The present application adopts segmented iron and aluminum removal for crude nickel-cobalt hydroxide, first, the high-acid leaching liquid after first high-acid leaching is mixed with emulsified second ore slurry for one-stage iron and aluminum removal to generate easily filtered residue phase second filtration residue; the second filtration residue is subjected to staged treatment, part of the second filtration residue (generally 20% to 70% of the total second filtration residue) is subjected to maturation leaching to further dissolve fine particles in the residue, promote the recovery of residual nickel-cobalt metal and improve the filterability, the other part of the second filtration residue is directly mixed with the second filtrate as a seed to improve the impurity precipitation of subsequent solid-liquid mixture A, through staged treatment, the treatment amount is reduced while the filterability is still effectively improved; the third filtrate after maturation leaching is mixed with the third filtration residue in proportion to maintain the ionic strength of the system and promote subsequent precipitation to prepare solid-liquid mixture B. Then, the solid-liquid mixture A and the solid-liquid mixture B are subjected to two-stage iron and aluminum removal to improve the extraction rate of nickel-cobalt valuable metals and the removal rate of iron and aluminum impurities of crude nickel-cobalt hydroxide. Through the above segmented iron and aluminum removal treatment, the present application avoids precipitation loading and can improve the crystallinity of iron and aluminum precipitation, avoids the formation of colloids such as aluminum hydroxide Al(OH)3, Fe(OH)3 and silica gel, and further effectively improves the filterability. At the same time, through multi-stage heat preservation filtration, the present application can reduce the viscosity of the filtrate and improve the characteristics of the filter cake. For impurities such as aluminum hydroxide Al(OH)3, Fe(OH)3 and silica gel colloids which are easy to form in the residue, heat preservation filtration promotes their transformation into a form with higher crystallinity and more compact structure, which helps to improve the filtration efficiency and avoid pipeline blockage.

[0051] In the embodiments of the present application, the crude nickel-cobalt hydroxide contains 37-40% of nickel, 3-5% of cobalt, 4-7% of manganese, 0.01-0.05% of iron, 0.10-0.30% of aluminum, 0.50-0.80% of zinc and 0.15-0.30% of copper.

[0052] In a preferred embodiment of the present application, the mass concentration of the first ore slurry is 10-40%, for example, 10%, 15%, 20%, 25%, 30%, 35%, 40%. The mass concentration of the second ore slurry is 20-50%, for example, 20%, 25%, 30%, 35%, 40%, 45%, 50%. The present application controls the concentration of the second ore slurry so that the second ore slurry fully reacts with the leaching filtrate during the iron and aluminum removal reaction, and the hydroxyl ions in the second ore slurry and the iron and aluminum ions in the leaching filtrate undergo neutralization and hydrolysis precipitation reaction, effectively removing the content of impurity elements such as iron and aluminum in the leaching filtrate. The present application uses the alkaline substance (hydroxide) in the crude nickel-cobalt hydroxide itself as a neutralizing agent, which has the advantages of low cost, reduction of external reagent addition and resource utilization.

[0053] In order to further ensure the efficient leaching rate of nickel and cobalt elements in the first ore slurry and the specific form of ions in the filtration residue, avoid the formation of silica gel, Al(OH)3, Fe(OH)3 and other silica gels, and make the ions have good crystal structure to improve the filtration performance. In some preferred embodiments of the present application, the reaction temperature of the first high-acid leaching is 80-95°C, preferably 85-90°C, and the reaction time is 2-7h, preferably 3-6h. The mass ratio of the acid solution to the first ore slurry in the first high-acid leaching is 1:4-6. By controlling the mass ratio of the acid solution to the first ore slurry in the first high-acid leaching, the acidity of the solution after the first high-acid leaching is 30-50g / l, which inhibits the formation of colloids. The acid solution can be selected from sulfuric acid solution, and the mass fraction of the sulfuric acid solution is 80-98%. The first high-acid leaching is carried out under stirring, and the stirring speed is 300-800r / min, preferably 400-700r / min.

[0054] In order to further ensure the high leaching rate of nickel and cobalt elements in the first slurry and the specific form of ions in the filtered residue, avoid the formation of silica gel, Al(OH)3, Fe(OH)3 and other silica gels, and make the ions have a good crystal structure, the filtration performance is improved. In some preferred embodiments of the present application, 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 temperature of the reaction is 75-90℃, preferably 75-85℃, and the time is 3-6h, preferably 4-5h. The reaction is carried out under stirring, and the stirring speed is 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 speed of the emulsified second slurry, it is slowly and uniformly added to the first filtrate for sufficient reaction.

[0055] In order to further ensure the high leaching rate of nickel and cobalt elements in the first slurry and the specific form of ions in the filtered residue, avoid the formation of silica gel, Al(OH)3, Fe(OH)3 and other silica gels, and make the ions have a good crystal structure, the filtration performance is improved. In some preferred embodiments of the present application, 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 filtered residue in the aging leaching is 1:1.5-3.5. By controlling the mass ratio of the acid solution to the second filtered residue in the aging leaching, the acidity of the solution after the aging acid leaching is 30-50g / l, and the formation of colloids is inhibited. The acid solution may, for example, be selected from a sulfuric acid solution with a mass fraction of 80-98%. The aging leaching process is carried out under stirring, and the stirring speed is 300-800r / min. The second filtered residue is slowly added during the aging leaching process, and the feeding time is 30-90min.

[0056] In some preferred embodiments of the present application, in step S4, part of the second filtered residue is mixed with an acid solution for aging leaching, and the part of the second filtered residue accounts for 15-30% of the total mass of the second filtered 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 the solid-liquid mixture A and the solid-liquid mixture B, the amount of the second iron and aluminum removal reaction can be reasonably controlled, the ion content is maintained within an appropriate range without affecting the appropriate process parameters, and the filtration performance is improved.

[0057] In some preferred embodiments of the present application, 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 2-7h, preferably 3-6h. The mass ratio of the acid solution to the total of the solid-liquid mixture A and the 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 the solid-liquid mixture A and the solid-liquid mixture B in the second high-acid leaching, the acidity of the solution after the second high-acid leaching is 30-50g / l, and the formation of colloids is inhibited. The acid solution may, for example, be selected from a sulfuric acid solution with a mass fraction of 80-98%. The second high-acid leaching is carried out under stirring at a stirring speed of 300-800r / min, preferably 400-700r / min; and the solid-liquid mixture A and the solid-liquid mixture B are slowly fed during the second high-acid leaching, and the feeding time is 30-90min.

[0058] In order to further optimize the filtration performance in the process of leaching of the crude nickel-cobalt hydroxide, in some preferred embodiments of the present application, the temperature of the first heat preservation filtration is 40-80°C, preferably 50-75°C; the temperature of the second heat preservation filtration is 40-60°C, preferably 45-60°C; and the temperature of the third heat preservation filtration is 40-80°C, preferably 50-75°C.

[0059] In some preferred embodiments of the present application, 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°C, and the reaction time is 3-6h. The air input amount is 1-5L / min. By precisely controlling the reaction pH value, the present application can ensure that Fe(OH)3 and Al(OH)3 are almost completely precipitated and separated out, while Ni 2+ and Co 2+ are basically retained in the solution, and by synergistically controlling the reaction temperature and the reaction time, efficient removal of iron and aluminum and good slag filtration performance are ensured. Further, the mass ratio of the fourth filtrate to the second ore slurry is 1:1-3. By controlling the mass ratio of the fourth filtrate to the second ore slurry, the fourth filtrate and the second ore slurry can be fully reacted, and the content of impurity elements such as iron and aluminum in the solution can be effectively removed.

[0060] The present application is further described in detail below in conjunction with specific examples, which should not be understood as limiting the scope of the present application.

[0061] Example 1

[0062] A method for improving the filtration performance in the process of leaching of the crude nickel-cobalt hydroxide, comprising the following steps:

[0063] Step S1, take 900g crude nickel-cobalt hydroxide (MHP) and water to prepare a first slurry and a second slurry with a mass concentration of 20%, and then emulsify the first slurry and the second slurry. In the crude nickel-cobalt hydroxide, the content of nickel is 38%, the content of cobalt is 4%, the content of manganese is 5%, the content of iron is 0.03%, the content of aluminum is 0.23%, the content of zinc is 0.62%, and the content of copper is 0.24%.

[0064] Step S2, take a concentrated sulfuric acid solution with a mass fraction of 98% and put it into a reaction container, add the first slurry after emulsification to the reactor under the conditions of a temperature of 90°C and a stirring speed of 600r / min, and carry out first high-acid leaching for 5h; after the reaction is completed, carry out heat preservation and filtration under the condition of 70°C, and the time required for complete filtration of the material is 0.5h, to obtain first filter residue and first filtrate. The mass ratio of the concentrated sulfuric acid solution to the first slurry is 1:5.

[0065] Step S3, put the first filtrate obtained in step S2 into a reaction container, adjust the temperature to 80°C, and under the condition of a stirring speed of 400r / min, pass in air (2L / min) and add the second slurry after emulsification within 60min to make the pH value of the reaction system 5.5, and then continue to stir for 5h. The mass ratio of the first filtrate to the second slurry is 1:2.

[0066] Step S4, the time required for complete filtration of the material after the reaction in step S3 under the condition of 55°C is 0.1h, to obtain second filter residue and second filtrate, take the second filter residue with a mass ratio of 20% for aging leaching, and mix the remaining second filter residue and second filtrate to obtain a solid-liquid mixture A (the solid-liquid ratio is 1:3) for standby use. The specific process of the aging leaching is as follows: take a concentrated sulfuric acid solution with a mass fraction of 98% and put it into a reaction container, slowly add the second filter residue with a mass ratio of 20% to the reactor under the conditions of a temperature of 90°C and a stirring speed of 600r / min (the mass ratio of the concentrated sulfuric acid solution to the second filter residue is 1:5), and complete the addition within 20min, and stir for 6h.

[0067] Step S5, the time required for complete filtration of the material after the aging leaching in step S4 is 0.05h, to obtain third filter residue and third filtrate, mix the third filtrate and all the third filter residue in proportion to obtain a solid-liquid mixture B (the solid-liquid ratio is 1:5) for standby use.

[0068] Step S6, take the mass fraction of 98% concentrated sulfuric acid solution into the reaction vessel, under the condition of temperature 90℃ and stirring speed 600r / min, slowly add the above-mentioned solid-liquid mixture A and solid-liquid mixture B into the reaction vessel, complete the feeding within 30min, carry out the second high-acid leaching reaction for 5h, then carry out the heat preservation filtration of the material after the second high-acid leaching under the condition of 70℃, the time required for complete filtration of the material is 0.3h, and the fourth filtrate and the fourth filter residue are obtained. In the second high-acid leaching process, the mass ratio of the concentrated sulfuric acid solution to the sum of the solid-liquid mixture A and the solid-liquid mixture B is 1:5.

[0069] Step S7, put the fourth filtrate into the reaction vessel, adjust the temperature to 80℃, under the condition of stirring speed 400r / min, pass in air (2L / min), and add the emulsified second ore slurry within 60min to make the pH value of the reaction system 5.5, then continue to stir for 5h. In this embodiment, the mass ratio of the fourth filtrate to the second ore slurry is 1:2. The time required for complete filtration of the material after the reaction is 0.1h, and the nickel-cobalt rich solution is obtained. The nickel-cobalt rich solution is further purified to obtain pure materials such as battery-grade nickel sulfate and cobalt sulfate.

[0070] In the nickel-cobalt rich solution obtained in this embodiment, the recovery rate of nickel is 99.6%, and the recovery rate of cobalt is 98.3%. The total filtration time used in this embodiment for extracting the nickel-cobalt rich solution from the crude nickel-cobalt hydroxide is 1.05h.

[0071] Example 2

[0072] A method for improving the filtration performance in the leaching process of crude nickel-cobalt hydroxide, which is different 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 are subjected to heat preservation filtration under the condition of 50℃. The total filtration time used in this embodiment for extracting the nickel-cobalt rich solution from the crude nickel-cobalt hydroxide is 2.95h.

[0073] Example 3

[0074] A method for improving the filtration performance in the leaching process of crude nickel-cobalt hydroxide, which is different from example 1 in that the material after the first iron and aluminum removal reaction in step S4 and the material after the second iron and aluminum removal reaction in step S7 are subjected to heat preservation filtration under the condition of 45℃. The total filtration time used in this embodiment for extracting the nickel-cobalt rich solution from the crude nickel-cobalt hydroxide is 1.45h.

[0075] Comparative Example 1

[0076] A method for improving the filtration performance in the leaching process of crude nickel-cobalt hydroxide, which is different from example 1 in that the material after the first high-acid leaching in step S2 is filtered at room temperature (25°C), and the time required for completely filtering the above material is 4h, the material after the aging leaching in step S4 is filtered at room temperature (25°C), and the time required for completely filtering the above material is 2h, the material after the second high-acid leaching in step S6 is filtered at room temperature (25°C), and the time required for completely filtering the above material is 3h, and the material after the second iron and aluminum removal reaction in step S7 is filtered at room temperature (25°C), and the time required for completely filtering the above material is 2h. The total filtration time for extracting nickel and cobalt rich liquid from crude nickel-cobalt hydroxide in this comparative example is 11.05h.

[0077] Comparative example 2

[0078] A method for improving the filtration performance in the leaching process of crude nickel-cobalt hydroxide, which is different from example 1 in that the aging leaching process of step S4 is not present in this comparative example, and room temperature (25°C) filtration is used in each filtration stage, and the specific process is as follows:

[0079] Step S1, 900g of crude nickel-cobalt hydroxide (MHP) is mixed with water to prepare a first slurry and a second slurry with a mass concentration of 20%, and then the first slurry and the second slurry are emulsified. The nickel content in the crude nickel-cobalt hydroxide is 38%, the cobalt content is 4%, the manganese content is 5%, the iron content is 0.03%, the aluminum content is 0.23%, the zinc content is 0.62%, and the copper content is 0.24%.

[0080] Step S2, a concentrated sulfuric acid solution with a mass fraction of 98% is weighed and placed into a reaction container, and under the conditions of a temperature of 90°C and a stirring speed of 600r / min, the first emulsified slurry is added to the reactor for first high-acid leaching, and the reaction is carried out for 5h; after the reaction is completed, room temperature filtration is carried out, and the time required for completely filtering the material is 4h, and a first filter residue and a first filtrate are obtained. The mass ratio of the concentrated sulfuric acid solution to the first slurry is 1:5.

[0081] Step S3, the first filtrate obtained in step S2 is placed into a reaction container, the temperature is adjusted to 80°C, air is introduced (2L / min) under the condition of a stirring speed of 400r / min, and the second emulsified slurry is added within 60min to make the pH value of the reaction system 5.5, and then the stirring reaction is continued for 5h. The mass ratio of the first filtrate to the second slurry is 1:2.

[0082] Step S4, the material after the reaction in step S3 is filtered at room temperature, and the time required for completely filtering the material is 2h, and a second filter residue and a second filtrate are obtained.

[0083] Step S5, a 98% mass fraction of concentrated sulfuric acid solution is placed into a reaction container, and the second filter residue and the second filtrate of step S4 are slowly added into the reaction container under the conditions of a temperature of 90°C and a stirring speed of 600 r / min, the feeding is completed within 30 min, a second high-acid leaching reaction is performed for 5 h, and then the material after the second high-acid leaching is filtered at room temperature, the complete filtration of the material requires 6 h, and a third filtrate is obtained. In the second high-acid leaching process, the mass ratio of the concentrated sulfuric acid solution to the sum of the second filter residue and the second filtrate is 1:5.

[0084] Step S6, the third filtrate is placed into a reaction container, the temperature is adjusted to 80°C, air is introduced (2 L / min) under the condition of a stirring speed of 400 r / min, and the emulsified second ore slurry is added within 60 min to make the pH value of the reaction system 5.5, and then the stirring reaction is continued for 5 h. In the process, the mass ratio of the third filtrate to the second ore slurry is 1:2. The material after the reaction is filtered at room temperature, the complete filtration of the material requires 2 h, and a nickel-cobalt rich solution is obtained. The nickel-cobalt rich solution is further purified to obtain pure materials such as battery-grade nickel sulfate and cobalt sulfate.

[0085] In the nickel-cobalt rich solution obtained in the present comparative example, the recovery rate of nickel is 99.7%, and the recovery rate of cobalt is 98.6%. The total filtration time for extracting the nickel-cobalt rich solution from the crude nickel-cobalt hydroxide in the present comparative example is 14 h.

[0086] The above-described embodiments only represent the embodiments of the present application, and the description is relatively specific and detailed, but it should not be understood as the limitation of the scope of the present application, and the present application can also be implemented in other specific ways or other specific forms without deviating from the spirit or essential characteristics of the present application. Therefore, the described embodiments should be regarded as illustrative rather than limiting in any aspect. The scope of the present application should be illustrated by the appended claims, and any changes equivalent to the intent and scope of the claims should also be included in the scope of the present application.

Claims

1. A method for improving filtration performance in the leaching of crude nickel-cobalt hydroxide, characterized by, The method comprises the following steps: Step S1, mixing crude nickel-cobalt hydroxide with water to prepare a first slurry and a second slurry, and then emulsifying the first slurry and the second slurry; Step S2, mixing the emulsified first slurry with acid liquor to perform first high-acid leaching, and then performing first heat preservation filtration on the first high-acid leaching material, wherein the temperature of the first heat preservation filtration is 40-80℃, and first filtrate and first filter residue are obtained; Step S3, introducing air into the first filtrate, and adding the emulsified second slurry to perform first iron and aluminum removal reaction; Step S4, performing second heat preservation filtration on the material after the reaction in step S3, wherein the temperature of the second heat preservation filtration is 40-60℃, and second filter residue and second filtrate are obtained, part of the second filter residue is mixed with acid liquor to perform ripening leaching, and the remaining second filter residue and second filtrate are mixed to obtain a solid-liquid mixture A for standby; Step S5, performing filtration on the material after the ripening leaching in step S4 to obtain third filter residue and third filtrate, and mixing the third filtrate with the third filter residue in proportion to obtain a solid-liquid mixture B for standby; Step S6, mixing the solid-liquid mixture A, the solid-liquid mixture B and acid liquor to perform second high-acid leaching, and then performing third heat preservation filtration on the second high-acid leaching material, wherein the temperature of the third heat preservation filtration is 40-80℃, and fourth filtrate and fourth filter residue are obtained; wherein the solid-liquid ratio of the solid-liquid mixture A is 1:2-5, the solid-liquid ratio of the solid-liquid mixture B is 1:2-5, and the mass ratio of acid liquor to the sum of the solid-liquid mixture A and the solid-liquid mixture B in the second high-acid leaching is 1:4-6; Step S7, introducing air into the fourth filtrate, and adding the emulsified second slurry to perform second iron and aluminum removal reaction, and then performing filtration to obtain nickel-cobalt rich liquor.

2. The method for improving filtration performance in the leaching process of crude nickel-cobalt hydroxide according to claim 1, characterized by, 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 filtration performance in the leaching process of crude nickel-cobalt hydroxide according to claim 1, characterized by, 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 acid liquor to the first slurry in the first high-acid leaching is 1:4-6.

4. The method for improving filtration performance in the leaching process of crude nickel-cobalt hydroxide according to claim 1, characterized by, 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 introduction amount is 1-5L / min; And / or, in step S3, the emulsified second slurry is added to the first filtrate within 10-90min.

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

6. The method for improving filtration performance in the leaching process of crude nickel-cobalt hydroxide according to claim 1, characterized by, In step S4, the mass ratio of acid liquor to the second filter residue in the ripening leaching is 1:1.5-3.5; And / or, the second filter residue is slowly added during the ripening leaching, and the feeding time is 30-90min.

7. The method for improving filtration performance in the leaching process of crude nickel-cobalt hydroxide according to claim 1, characterized by, In step S6, the reaction temperature of the second high-acid leaching is 80-95℃, and the reaction time is 2-7h; And / or, slowly feeding solid-liquid mixture A and solid-liquid mixture B in the second high-acid leaching process, the feeding time is 30-90 min.

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

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