A co-precipitation method of MHP based on the ratio of ternary precursors

Abstract

The invention relates to a co-precipitation method of MHP (Mixed Hydroxide Precipitate) based on the ratio of ternary precursors. The method configures a mixed salt solution required for the precipitation of MHP according to the nickel-cobalt-manganese ratio of the ternary precursor to be prepared. It is divided into two parts, where a small part of the mixed salt solution is mixed with ammonia water and a precipitant to form a pre-precipitation solution. This pre-precipitation solution will generate a preliminary hydroxide of nickel-cobalt-manganese, which serves as a precipitation base for hydroxide of nickel-cobalt-manganese when mixed with another mixed salt solution with a larger content and a precipitant, promoting the subsequent precipitation of hydroxide of nickel-cobalt-manganese. The complexing agent EDTA introduced can use the stability difference of complexes of metals such as nickel, cobalt, and manganese under different pH conditions to improve the co-precipitation effect of nickel-cobalt-manganese and reduce impurity content. At the same time, the co-precipitation reaction process is set with two stages of temperature, which can effectively suppress the moisture content of the hydroxide of nickel-cobalt-manganese product, making the moisture content below 60%.

Description

[0001] Description

[0002] A CO -PRE CI PI TAT I ON METHOD OF MHP BASED ON THE RATIO OF TERNARY

[0003] PRECURSORS

[0004] Field Of The Disclosure

[0005] This invention pertains to the field of hydrometallurgy, speci fically to a co-precipitation method of MHP based on the ratio of ternary precursors .

[0006] Background

[0007] Ternary cathode materials of nickel-cobalt-manganese , commonly referred to as lithium nickel-cobalt-manganese oxide with the chemical formula Li (NixCoyMn ( 1-x-y ) ) 02 , are a key type of electrode material used in lithium-ion batteries . They are widely applied in electric vehicles , mobile devices , energy storage systems , and other fields . In particular, lithium nickel-cobalt-manganese oxide is extensively used in power-type cylindrical lithium-ion batteries due to its high energy density and excellent performance . The current ternary cathode materials ( referred to as NCM) include types such as NCM523 , NCM622 , and NCM811 , where the numbers represent the molar ratios of nickel , cobalt , and manganese .

[0008] The ternary precursors of nickel-cobalt-manganese are primarily synthesi zed from nickel-cobalt-manganese hydroxides and lithium salts through high-temperature sintering, thus the quality of the precursors greatly influences the performance of the resulting cathode materials . The precursors , typically nickel-cobalt-manganese hydroxides with the chemical formula (NixCoyMn ( 1-x-y ) ( OH) 2 ) , are key intermediates in the preparation of ternary cathode materials . With the rapid development of new energy vehicles and energy storage , the market demand for high-performance lithium-ion batteries is continuously increasing, which has driven the market for nickel-cobalt-manganese precursors and intensi fied the demand for raw materials such as nickel , cobalt , and manganese required for their synthesis . At present , lateritic nickel ore is one of the important sources of nickel and contains certain amounts of cobalt and manganese , playing a key role in the production of ternary precursors . Its abundant reserves and mine ability provide a stable raw material supply for the development of the ternary precursor industry . Existing processes commonly use hydrometallurgical processes of lateritic nickel ore to separately extract high-purity nickel , cobalt , and manganese salts required for the preparation of ternary precursors .

[0009] Due to the di f ficulty in controlling the co-precipitation of nickel , cobalt , and manganese in the existing hydrometallurgical process of precipitating MHP ( i . e . , nickel-cobalt hydroxide ) , the resulting nickel-cobalt-manganese hydroxide often does not meet the desired ratio for the precursor . Additionally, the hydroxide obtained from the MHP precipitation process contains higher impurities and water content , which is not conducive to its direct use in the preparation of precursors . This necessitates further separation of nickel , cobalt, and manganese after the MHP precipitation process , such as subsequent extraction processes , making the existing hydrometallurgical process lengthy and costly . To reduce the costs o f the existing hydrometallurgical process of lateritic nickel ore , there is an urgent need for a new process to address the aforementioned shortcomings in the existing MHP precipitation process .

[0010] Summary

[0011] The purpose of this invention is to overcome the above-mentioned technical deficiencies and provide a co-precipitation method of MHP based on the ratio of ternary precursors . It addresses the technical issues in the existing technology where it i s di f ficult to co-precipitate nickel , cobalt , and manganese in the MHP precipitation process , and the resulting nickel-cobalt-manganese hydroxide meets the ratio required for the precursor .

[0012] To achieve the above technical purpose , the technical solution provided by this invention is :

[0013] This invention provides a co-precipitation method of MHP based on the ratio of ternary precursors , including the following steps : S I , adj usting the ratio of nickel , cobalt , and manganese in the liquid after iron-aluminum-chromium removal according to the ratio of the ternary precursor to be prepared, and concentrating it into a first mixed salt solution and a second mixed salt solution after distribution; S2, mixing the first mixed salt solution, water, ammonia water, and precipitant evenly to obtain a pre-precipitation solution; S3, adding the second mixed salt solution, precipitant, and complexing agent synchronously to the pre-precipitation solution for the precipitation reaction, and obtaining the final product of nickel-cobalt-manganese hydroxide after filtration; the complexing agent is EDTA.

[0014] Preferred, in step SI, the chemical formula of the ternary precursor to be prepared is NixCoyMnz(OH) 2, where 0.5<x<l , 0<y<l, 0<z<l, and x+y+z=l; the nickel-cobalt-manganese ratio may include any of 5:2:3, 6:2:2, 8:1:1, 9:0.5:0.5, and the ternary precursor to be prepared can cover the nickel-cobalt-manganese ratio of any ternary precursor in the 5~9 series; specifically, nickel-cobalt post-precipitation liquid, manganese slag, manganese salts, etc., can be reused as manganese regulators, and cobalt salts can be used as cobalt regulators to adjust the ratio of nickel-cobalt-manganese in the liquid after iron-aluminum-chromium removal, so that the ratio is adapted to the nickel-cobalt-manganese ratio of the subsequent ternary precursor.

[0015] Preferred, in step SI, after concentration, the sum of the concentrations of nickel, cobalt, and manganese elements in the first mixed salt solution is 0.7~1.1 mol / L, and the sum of the concentrations of nickel, cobalt, and manganese elements in the second mixed salt solution is 0.7~l.l mol / L.

[0016] Preferred, in step SI, the volume ratio of the first mixed salt solution to the second mixed salt solution is 1 : ( 9~20 ) .

[0017] Preferred, in step S2, the specific steps of step S2 are as follows: water, ammonia water, and precipitant are added to the reaction kettle and mixed, the pH is adjusted to 9~11, the temperature is raised to 60~80°C, and then the first mixed salt solution is added to the reaction kettle for a reaction of 1~2 hours to obtain a pre-precipitation solution. Among them, the concentration of the precipitant solution is 4~10 mol / L, and the concentration of ammonia water is 3~8 mol / L. Preferred, in step S2, the precipitant includes at least one of sodium carbonate and sodium hydroxide.

[0018] Preferred, the specific steps of step S3 are as follows: the second mixed salt solution, precipitant, and complexing agent are added synchronously to the pre-precipitation solution at a preset flow rate for co-precipitation reaction, the pH is maintained at 7.5-8.5 during the reaction process, the temperature is 50-70°C and does not include 70°C, and the time to add the complexing agent is 2-4 hours; then the temperature is quickly raised to 70-90°C, the second mixed salt solution and precipitant continue to be added, the pH value is maintained at 7.5-8.5, the reaction is maintained for 1-2 hours, and the nickel-cobalt-manganese hydroxide product is obtained after filtration .

[0019] Preferred, in step S3, the flow rate ratio of the second mixed salt solution, precipitant, and complexing agent is (2.6-3.0) : 1 : (0.3-0.5) .

[0020] Preferred, in step S3, the precipitant includes at least one of sodium carbonate and sodium hydroxide.

[0021] Preferred, the concentration of the complexing agent is 0.01-0.1 mo 1 / L .

[0022] Compared with the existing technology, the beneficial effects of the present invention include:

[0023] The invention configures the mixed salt solution required for the precipitation of MHP based on the nickel-cobalt-manganese ratio of the ternary precursor to be prepared, and divides it into two parts. A small part of the mixed salt solution is mixed with ammonia water and a precipitant to form a pre-precipitation solution, which will preliminarily generate a hydroxide of nickel-cobalt-manganese. This pre-precipitation solution, when mixed with another mixed salt solution with a larger content and a precipitant, can serve as a precipitation base for hydroxide of nickel-cobalt-manganese, promoting the subsequent precipitation of hydroxide of nickel-cobalt-manganese. The introduced complexing agent EDTA can utilize the stability difference of complexes of metals such as nickel, cobalt, manganese, and magnesium under different pH conditions to enhance the co-precipitation effect of nickel-cobalt-manganese and reduce impurity content. At the same time, the co-precipitation reaction process is set with two stages of temperature , which can ef fectively suppress the moisture content of the final product of nickel-cobalt-manganese hydroxide , keeping the moisture content below 60% .

[0024] Brief Description Of The Drawings

[0025] FIG . l is a flowchart of an embodiment of the MHP co-precipitation method based on the ratio of ternary precursors according to the present invention .

[0026] Detailed Description Of Preferred Embodiments

[0027] To make the obj ectives , technical solutions , and advantages of the present invention clearer, the following further detailed description of the invention is combined with the drawings and examples . It should be understood that the speci fic examples described here are only for the purpose of explaining the invention and do not limit the invention .

[0028] In the description of the embodiment of this application, technical terms such as " first , " " second, " etc . , are used only to distinguish di f ferent obj ects and should not be understood as indicating or implying relative importance or implicitly speci fying the number of technical features , a speci fic order, or a primary / secondary relationship . In the description of the embodiment of this application, "multiple" means more than two unless otherwise speci fically limited .

[0029] The term " embodiment" mentioned in this text means that speci fic features , structures , or characteristics described in conj unction with the embodiment can be included in at least one embodiment of this application . The phrase appearing in various places in the speci fication does not necessarily refer to the same embodiment and is not an independent or alternative embodiment that is exclusive of other embodiments . Those skilled in the art understand both explicitly and implicitly that the examples described herein can be combined with other examples .

[0030] The existing lateritic nickel ore hydrometallurgical process is : ore dressing - high-pressure leaching - CCD countercurrent washing - iron-aluminum-chromium removal - MHP precipitation - tailings treatment. In the MHP precipitation process, sodium hydroxide is usually added to the liquid after iron-aluminum-chromium removal for precipitation, forming nickel-cobalt hydroxide and enriching nickel and cobalt. In the actual MHP precipitation process, the KSP of nickel hydroxide is 2.0xl0~15, the KSP of cobalt hydroxide is 5.92xl0~15, the KSP of manganese hydroxide is 1.9xl0~13, and the KSP of magnesium hydroxide is 1.8X1CM11. According to the solubility products of various metal hydroxides, the KSP of nickel hydroxide and cobalt hydroxide are close, allowing them to co-precipitate preferentially, followed by the precipitation of manganese and magnesium. Since the solubility product of manganese hydroxide differs by two orders of magnitude from that of nickel-cobalt hydroxide, it is difficult to achieve co-precipitation of nickel, cobalt, and manganese. In response to this existing problem, the present invention proposes the following solution .

[0031] The present invention provides a co-precipitation method of MHP based on the ratio of ternary precursors, including the following steps :

[0032] 51, based on the nickel-cobalt-manganese ratio of the ternary precursor to be prepared, the ratio of nickel, cobalt, and manganese in the liquid after the removal of iron, aluminum, and chromium is adjusted, and after concentration, it is distributed into a first mixed salt solution and a second mixed salt solution.

[0033] 52, the first mixed salt solution, water, ammonia water, and precipitant are mixed evenly to obtain a pre-precipi tation solution.

[0034] 53, the second mixed salt solution, precipitant, and complexing agent are added synchronously to the pre-precipitation solution for precipitation reaction, and after filtration, the final product of nickel-cobalt-manganese hydroxide is obtained; the complexing agent is EDTA.

[0035] In some embodiments, in step SI, the chemical formula of the ternary precursor to be prepared is NixCoyMnz(OH) 2, where 0.5<x<l , 0<y<l, 0<z<l, and x+y+z=l; the nickel-cobalt-manganese ratio may include any of 5:2:3, 6:2:2, 8:1:1, 9:0.5:0.5, and the ternary precursor to be prepared can cover the nickel-cobalt-manganese ratio of any ternary precursor in the 5~9 series; specifically, the nickel-cobalt post-precipitation liquid, manganese slag, manganese salts, etc., can be reused as manganese regulators, and cobalt salts can be used as cobalt regulators to adjust the ratio of nickel, cobalt, and manganese in the liquid after the removal of iron, aluminum, and chromium, so that the ratio is adapted to the nickel-cobalt-manganese ratio of the subsequent ternary precursor.

[0036] In some embodiments, in step SI, after concentration, the sum of the concentrations of nickel, cobalt, and manganese elements in the first mixed salt solution is 0.7~l.l mol / L, and the sum of the concentrations of nickel, cobalt, and manganese elements in the second mixed salt solution is 0.7~l.l mol / L; specifically, after concentration, the sum of the concentrations of nickel, cobalt, and manganese elements in the first and second mixed salt solutions is 0.7 mol / L, 0.8 mol / L, 0.9 mol / L, 1.0 mol / L, 1.1 mol / L, or other values within this range.

[0037] In some embodiments, in step SI, the volume ratio of the first mixed salt solution to the second mixed salt solution is 1: (9~20) ; for the distribution of the mixed salt solutions, only a small amount needs to be separated as the first mixed salt solution for preparing the pre-precipitation solution, so that the small amount of pre-formed nickel-cobalt-manganese hydroxide can promote the subsequent reaction precipitation without affecting the subsequent precipitation ratio of nickel-cobalt-manganese hydroxide.

[0038] In some embodiments, in step S2, the specific steps of step S2 are as follows: water, ammonia water, and precipitant are added to the reaction kettle and mixed, the pH is adjusted to 9~11, the temperature is raised to 60~80°C, and then the first mixed salt solution is added to the reaction kettle for a reaction of 1~2 hours to obtain a pre-precipitation solution. Among them, the concentration of the precipitant solution is 4~10 mol / L, and the concentration of ammonia water is 3~8 mol / L. Specifically, in step S2, the pH can be adjusted to 9, 9.5, 10, 10.5, 11, or other values within this range, the reaction temperature can be adjusted to 60°C, 65°C, 70°C, 75°C, 80°C, or other values within this range, and the reaction time can be controlled at 1 hour, 1.5 hours, 2 hours, or other values within this range. In some embodiments, in step S2, the precipitant includes at least one of sodium carbonate and sodium hydroxide.

[0039] In some embodiments, the specific steps of step S3 are as follows: the second mixed salt solution, precipitant, and complexing agent are added synchronously to the pre-precipitation solution at a preset flow rate for co-precipitation reaction, the pH is maintained at 7.5~8.5 during the reaction process, the temperature is maintained at 50~70°C and does not include 70°C, and the time to add the complexing agent is 2~4 hours; then the temperature is quickly raised to 70~90°C, maintained for 1~2 hours, and after filtration, the final product of nickel-cobalt-manganese hydroxide is obtained. Specifically, in step S3, the pH can be adjusted to 7.5, 8, 8.5, or other values within this range, the temperature during the addition of the complexing agent can be adjusted to 50°C, 55°C, 60°C, 65°C, 68°C, or other values within this range, the time to add the complexing agent can be controlled at 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, or other values within this range, after the completion of the addition of the complexing agent, the temperature can be quickly raised to 70°C, 75°C, 80°C, 85°C, 90°C, or other values within this range, and the temperature is maintained for 1 hour, 1.5 hours, 2 hours, or other values within this range.

[0040] The mechanism behind the settings of the aforementioned Step S3 is as follows:

[0041] 1) The introduction of EDTA as a complexing agent serves two purposes. On one hand, considering the stability constants (LgK) of different metal ions with the complexing agent, the LgK for nickel ions is 18.56, for cobalt ions is 16.21, for manganese ions is 13.98, and for magnesium ions is 8.69. The LgK values for nickel, cobalt, and manganese are relatively close to each other but significantly different from that of magnesium. Since the main impurity in the co-precipitation reaction system is magnesium, the stability difference between the complexing agent and nickel, cobalt, manganese, and magnesium allows for preferential complexing of nickel, cobalt, and manganese, thus promoting their co-precipitation. On the other hand, the complexing capacity of different metal ions also has a suitable pH range. It has been experimentally verified that the appropriate pH range for EDTA to complex magnesium ions is 9 to 11, while the co-precipitation reaction in this invention is controlled at a pH of 7.5 to 8.5, making the pH conditions more suitable for the complexing of nickel, cobalt, and manganese and less suitable for magnesium complexing, thereby further promoting the stability of their complexing.

[0042] 2) Temperature significantly affects the complexing activity of EDTA. Maintaining suitable complexing temperature conditions during the addition of the complexing agent allows for better complexing with nickel, cobalt, and manganese. After the complexing agent is added, rapidly increasing the temperature beyond the optimal complexing temperature conditions for EDTA and nickel, cobalt, and manganese ions inhibits their complexing degree, thereby suppressing the crystallization water of their complexes, ensuring that the water content of the final nickel-cobalt-manganese hydroxide product is not too high.

[0043] In some embodiments, in Step S3, the flow rate ratio of the second mixed salt solution, precipitant, and complexing agent is ( 2.6~3.0 ) : 1 : ( 0.3~0.5 ) , controlling the raw material ratio through the flow rates of these three components.

[0044] In some embodiments, in Step S3, the precipitant includes at least one of sodium carbonate and sodium hydroxide.

[0045] In some embodiments, the concentration of the complexing agent is 0.01~0.1 mol / L, with able options of 0.02 mol / L, 0.04 mol / L, 0.06 mol / L, 0.08 mol / L, 0.1 mol / L, or other values within this range.

[0046] Further detailed descriptions of the invention are provided below through specific examples. To avoid redundancy, the liquid from lateritic nickel ore after iron-aluminum removal used in the examples and comparative examples is described as follows:

[0047] The liquid from lateritic nickel ore after iron-aluminum removal used in this invention is the liquid phase obtained after the lateritic nickel ore undergoes high-pressure acid leaching, the first stage of iron-aluminum removal, and the second stage of iron-aluminum removal, with the main components shown in Table 1 below.

[0048] Table 1 : Composition of Liquid from Lateritic Nickel Ore After Second Stage of Iron-aluminum Removal (g / L)

[0049] Ni Co Mn Fe Al Zn Cu Ca Mg 3.32 0.29 1.98 0.0006 0.003 0.0024 0.006 0.48 8.79

[0050] Embodiment 1

[0051] In this Embodiment, the MHP co-precipitation method based on the ternary precursor ratio is as follows:

[0052] (1) Based on the molar ratio of nickel, cobalt, and manganese of 5:2:3 for the ternary precursor to be prepared, the ratio of nickel, cobalt, and manganese in the liquid after iron-aluminum-chrome removal is adjusted. After concentration, it is divided in a 1:20 ratio to form the first mixed salt solution and the second mixed salt solution, with the sum of nickel , cobalt, and manganese concentrations in the first mixed salt solution being 0.8 mol / L, and the same for the second mixed salt solution.

[0053] (2) The first mixed salt solution, water, ammonia water, and sodium hydroxide solution are mixed evenly. The sodium hydroxide solution concentration is 5 mol / L, and the ammonia water concentration is 4 mol / L. The first co-precipitation reaction is carried out for 1 hour at pH 9 and a temperature of 60°C, resulting in a pre-precipitation solution .

[0054] (3) Take an EDTA solution with a concentration of 0.01 mol / L, and add the second mixed salt solution, sodium hydroxide solution, and EDTA synchronously at a flow rate ratio of 2.6: 1:0.3 into the pre-precipitation solution. The co-precipitation reaction is carried out for 4 hours at a pH value of 7.5 and a temperature of 50°C. Then, rapidly increase the temperature to 90°C, continue to add the second mixed salt solution and precipitant, maintain the pH at 7.5, and maintain the reaction for 1 hour. After filtration, obtain the final product of nickel-cobalt-manganese hydroxide.

[0055] Embodiment 2

[0056] In this Embodiment, the MHP co-precipitation method based on the ternary precursor ratio is as follows:

[0057] (1) Based on the molar ratio of nickel, cobalt, and manganese of 6:2:2 for the ternary precursor to be prepared, the ratio of nickel, cobalt, and manganese in the liquid after iron-aluminum-chrome removal is adjusted. After concentration, it is divided in a 1:15 ratio to form the first mixed salt solution and the second mixed salt solution, with the sum of nickel , cobalt, and manganese concentrations in the first mixed salt solution being 0.7 mol / L, and the same for the second mixed salt solution.

[0058] (2) The first mixed salt solution, water, ammonia water, and sodium hydroxide solution are mixed evenly. The sodium hydroxide solution concentration is 4 mol / L, and the ammonia water concentration is 5 mol / L. The first co-precipitation reaction is carried out for 1 hour at pH 10 and a temperature of 70°C, resulting in a pre-precipitation solution .

[0059] (3) Take an EDTA solution with a concentration of 0.05 mol / L, and add the second mixed salt solution, sodium hydroxide solution, and EDTA synchronously at a flow rate ratio of 2.8: 1:0.4 into the pre-precipitation solution. The co-precipitation reaction is carried out for 2 hours at a pH value of 8.0 and a temperature of 60°C. Then, rapidly increase the temperature to 70°C, continue to add the second mixed salt solution and precipitant, maintain the pH at 8.0, and maintain the reaction for 1.5 hours. After filtration, obtain the final product of nickel-cobalt-manganese hydroxide.

[0060] Embodiment 3

[0061] In this Embodiment, the MHP co-precipitation method based on the ternary precursor ratio is as follows:

[0062] (1) Based on the molar ratio of nickel, cobalt, and manganese of 8:1:1 for the ternary precursor to be prepared, the ratio of nickel, cobalt, and manganese in the liquid after iron-aluminum-chrome removal is adjusted. After concentration, it is divided in a 1:12 ratio to form the first mixed salt solution and the second mixed salt solution, with the sum of nickel , cobalt, and manganese concentrations in the first mixed salt solution being 0.8 mol / L, and the same for the second mixed salt solution.

[0063] (2) The first mixed salt solution, water, ammonia water, and sodium hydroxide solution are mixed evenly. The sodium hydroxide solution concentration is 5 mol / L, and the ammonia water concentration is 7 mol / L. The first co-precipitation reaction is carried out for 1 hour at pH 10.5 and a temperature of 70°C, resulting in a pre-precipitation solution .

[0064] (3) Take an EDTA solution with a concentration of 0.05 mol / L, and add the second mixed salt solution, sodium hydroxide solution, and EDTA synchronously at a flow rate ratio of 2.9: 1:0.3 into the pre-precipitation solution. The co-precipitation reaction is carried out for 4 hours at a pH value of 8.0 and a temperature of 60°C. Then, rapidly increase the temperature to 90°C, continue to add the second mixed salt solution and precipitant, maintain the pH at 8.0, and maintain the reaction for 1 hours. After filtration, obtain the final product of nickel-cobalt-manganese hydroxide.

[0065] Embodiment 4

[0066] In this Embodiment, the MHP co-precipitation method based on the ternary precursor ratio is as follows:

[0067] (1) Based on the molar ratio of nickel, cobalt, and manganese of 9 : 0.5 : 0.5 for the ternary precursor to be prepared, the ratio of nickel, cobalt, and manganese in the liquid after iron-aluminum-chrome removal is adjusted. After concentration, it is divided in a 1:9 ratio to form the first mixed salt solution and the second mixed salt solution, with the sum of nickel , cobalt, and manganese concentrations in the first mixed salt solution being 1.1 mol / L, and the same for the second mixed salt solution.

[0068] (2) The first mixed salt solution, water, ammonia water, and sodium hydroxide solution are mixed evenly. The sodium hydroxide solution concentration is 10 mol / L, and the ammonia water concentration is 8 mol / L. The first co-precipitation reaction is carried out for 1 hour at pH 11 and a temperature of 75°C, resulting in a pre-precipitation solution.

[0069] (3) Take an EDTA solution with a concentration of 0.1 mol / L, and add the second mixed salt solution, sodium hydroxide solution, and EDTA synchronously at a flow rate ratio of 3.0:1: 0.5 into the pre-precipitation solution. The co-precipitation reaction is carried out for 3 hours at a pH value of 8.5 and a temperature of 70°C. Then, rapidly increase the temperature to 80°C, continue to add the second mixed salt solution and precipitant, maintain the pH at 8.5, and maintain the reaction for 2 hours. After filtration, obtain the final product of nickel-cobalt-manganese hydroxide.

[0070] Comparative Example 1 (Without Pre-precipitation Liquid Preparation)

[0071] In this comparative example, the specific steps are as follows:

[0072] (1) Based on the molar ratio of nickel, cobalt, and manganese of 8:1:1 for the trivalent precursor to be prepared, the ratio of nickel, cobalt, and manganese in the liquid after iron-aluminum-chromium removal is adjusted. After concentration, it is divided in a 1:12 ratio to form a mixed salt solution, with the sum of nickel, cobalt, and manganese concentrations in the mixed salt solution being 0.8 mo 1 / L .

[0073] (2) Take an EDTA solution with a concentration of 0.05 mol / L, and add the mixed salt solution, sodium hydroxide solution, and EDTA synchronously at a flow rate ratio of 2.9: 1:0.3 into the pre-precipitation solution. The co-precipitation reaction is carried out for 4 hours at a pH value of 8.0 and a temperature of 60°C. Then, rapidly increase the temperature to 90°C, continue to add the second mixed salt solution and precipitant, maintain the pH at 8.0, and maintain the reaction for 1 hour. After filtration, obtain the final product of nickel-cobalt-manganese hydroxide.

[0074] Comparative Example 2 (No Temperature Increase After Complexing Agent Addition)

[0075] This comparative example is based on the steps of Embodiment 3, with only the step (3) adjusted, as follows:

[0076] (3) Take an EDTA solution with a concentration of 0.05 mol / L, and add the second mixed salt solution, sodium hydroxide solution, and EDTA synchronously at a flow rate ratio of 2.9: 1:0.3 into the pre-precipitation solution. The precipitation reaction is carried out for 4 hours at a pH value of 8.0 and a temperature of 60°C. Then, maintain the temperature at 60°C, continue to add the second mixed salt solution and precipitant, maintain the pH at 8.0, and maintain the reaction for 1 hour. After filtration, obtain the final product of nickel-cobalt-manganese hydroxide.

[0077] Comparative Example 3 (Excessive pH During Complexing Reaction)

[0078] This comparative example is based on the steps of Embodiment 3, with only the step (3) adjusted, as follows:

[0079] (3) Take an EDTA solution with a concentration of 0.05 mol / L, and add the second mixed salt solution, sodium hydroxide solution, and EDTA synchronously at a flow rate ratio of 2.9: 1:0.3 into the pre-precipitation solution. The co-precipitation reaction is carried out for 4 hours at a pH value of 9.5 and a temperature of 60°C. Then, rapidly increase the temperature to 90°C, continue to add the second mixed salt solution and precipitant, maintain the pH at 9.5, and maintain the reaction for 1 hour. After filtration, obtain the final product of nickel-cobalt-manganese hydroxide.

[0080] Comparative Example 4 (Excessive Temperature During Complexing Reaction)

[0081] This comparative example is based on the steps of Embodiment 3, with only the step (3) adjusted, as follows:

[0082] (3) Take an EDTA solution with a concentration of 0.05 mol / L, and add the second mixed salt solution, sodium hydroxide solution, and EDTA synchronously at a flow rate ratio of 2.9: 1:0.3 into the pre-precipitation solution. The co-precipitation reaction is carried out for 4 hours at a pH value of 9.5 and a temperature of 90°C. Then, keep the temperature at 90°C, continue to add the second mixed salt solution and precipitant, maintain the pH at 8.0, and maintain the reaction for 1 hour. After filtration, obtain the final product of nickel-cobalt-manganese hydroxide .

[0083] Test Embodiment

[0084] The molar ratios of nickel, cobalt, and manganese, magnesium mass fraction, and moisture content of the nickel-cobalt-manganese hydroxide products prepared in Embodiments 1 to 4 and Comparative Examples 1 to 4 are shown in Table 2.

[0085] Table 2

[0086] It can be seen from Embodiments 1 to 4 that the molar ratios of nickel , cobalt , and manganese in the prepared nickel-cobalt-manganese hydroxide products are very close to the initial molar ratios of the trivalent precursors to be prepared, proving that the MHP co-precipitation method based on the trivalent precursor ratio as described in this invention can achieve good co-precipitation of nickel , cobalt , and manganese . At the same time , the magnesium impurity content is low, and the moisture content is also controlled below 60% .

[0087] Comparing Test Embodiment 3 with Comparative Example 1 , it is evident that without the introduction of a pre-precipitation liquid, the precipitation rate of nickel , cobalt , and manganese is reduced by 8 % for Ni , 5% for Co , and 9% for Mn, respectively .

[0088] Comparing Embodiment 3 with Comparative Example 2 , it is found that not increasing the temperature after the addition of the complexing agent leads to an uncontrolled complexing process of EDTA, resulting in a signi ficantly increased moisture content in the final nickel-cobalt-manganese hydroxide product .

[0089] Comparing Embodiment 3 with Comparative Example 3 , it is observed that raising the pH during the complexing reaction reduces the complexing degree of EDTA with nickel , cobalt , and manganese , while increasing it with magnesium, leading to fluctuations in the molar ratios of nickel , cobalt , and manganese , and a noticeable increase in magnesium impurity content .

[0090] Comparative testing of the nickel-cobalt-manganese hydroxide products prepared from Embodiment 3 and Comparative Example 4 sh owed that, relative to Example 3, the mass percentage of Ni was reduced by 6%, that of Co by 2%, and that of Mn by 8% in Compara five Example 4. This indicates that the reaction temperature was increased in the complexation reaction process of Comparative E xample 4 relative to Example 3, causing the temperature conditio ns to exceed the suitable complexation range for EDTA with nicke 1, cobalt, and manganese. This resulted in a reduced complexatio n degree of EDTA with nickel, cobalt, and manganese, thereby dec reasing the precipitation rate of these metals.

[0091] The specific implementation of the invention described above does not limit the scope of protection of the invention. Any other corresponding changes and modifications made according to the technical concept of the invention should be included in the scope of the claims of the invention.

Claims

What Is Claimed Is1. A co-precipitation method of MHP based on the ratio of ternary precursors, characterized by the following steps:51, adjusting the nickel-cobalt-manganese ratio in the liquid after iron-aluminum-chromium removal according to the nickel-cobalt-manganese ratio of the ternary precursor to be prepared And after concentration, it is divided into the first mixed salt solution and the second mixed salt solution;52, mixing the first mixed salt solution, water, ammonia water, and precipitant evenly to obtain a pre-precipitation solution;53, adding the second mixed salt solution, precipitant, and complexing agent synchronously to the pre-precipitation solution for precipitation reaction, and obtaining the final product of nickel-cobalt-manganese hydroxide after filtration;The complexing agent is EDTA.

2. According to claim 1, the MHP coprecipitation method based on ternary precursor ratio is characterized in that in SI step, the chemical formula of ternary precursor to be prepared is NixCoyMnz(OH) 2, where 0.5<x<l, 0<y<l, 0<z<l, and x+y+z = 1.

3. According to Claim 1, the MHP co-precipitation method based on ternary precursor ratio is characterized in that in the SI step, the concentration of the sum of nickel, cobalt and manganese elements in the first mixed salt solution after concentration is 0.7~l.l mol / L, and the concentration of the sum of nickel, cobalt and manganese elements in the second mixed salt solution is 0.7~l.l mol / L.

4. According to Claim 3, the MHP coprecipitation method based on ternary precursor ratio is characterized in that the volume ratio of the first mixed salt solution to the second mixed salt solution in the SI step is 1: (9~20) .

5. According to Claim 4, the MHP coprecipitation method based on ternary precursor ratio is characterized in that, in the S2 step, the specific steps of the S2 step are as follows: Add water, ammonia andprecipitant to the reaction kettle to mix, adjust the pH to 9~11, heat up to 60~80°C, and then add the first mixed salt solution to the reaction kettle for 1~2 h, get the pre-precipit at ion solution; The concentration of the precipitant solution is 4~10 mol / L, and the concentration of ammonia is 3~8 mol / L.

6. According to claim 4, the MHP co-precipitation method based on ternary precursor ratio is characterized in that in the S2 step, the precipitant includes at least one of sodium carbonate and sodium hydroxide .

7. According to Claim 1, the MHP co-precipitation method based on ternary precursor ratio is characterized in that the specific steps of the S3 step are as follows: The second mixed salt solution, precipitant and complexing agent are added synchronously to the preset flow rate to carry out the co-precipitation reaction. During the reaction, the pH is maintained at 7.5~8.5, the temperature is 50~70°C without 70°C, and the complexing agent is added for 2~4 h. Then rapidly heating to 70~90°C, the second mixed salt solution and precipitant continue to add, pH value to maintain 7.5~8.5, maintain the reaction for 1~2 h, after filtration to obtain nickel cobalt manganese hydroxide products.

8. According to claim 7, the MHP co-precipitation method based on ternary precursor ratio is characterized in that the flow rate ratio of the second mixed salt solution, precipitant and complexing agent in the S3 step is (2.6~3.0) :1: (0.3~0.5) .

9. According to claim 7, the MHP co-precipitation method based on ternary precursor ratio is characterized in that in the S3 step, the precipitant includes at least one of sodium carbonate and sodium hydroxide .

10. According to claim 7, the MHP co-precipitation method based on ternary precursor ratio is characterized in that the concentration of the complexing agent is 0.01~0.1 mol / L.

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