A mhp coprecipitation method based on ternary precursor proportioning

Abstract

The application provides a MHP coprecipitation method based on ternary precursor proportion, and relates to the technical field of hydrometallurgy, and comprises the following steps: S1, based on the nickel-cobalt-manganese ratio of a ternary precursor to be prepared, adjusting the nickel-cobalt-manganese ratio contained in a liquid after iron, aluminum and chromium are removed, and obtaining a concentrated liquid which is distributed into a first mixed salt solution and a second mixed salt solution; S2, uniformly mixing water, ammonia, a precipitant and the first mixed salt solution to obtain a pre-precipitation liquid; S3, synchronously adding the second mixed salt solution, the precipitant and a complexing agent into the pre-precipitation liquid to perform a precipitation reaction, and preparing nickel-cobalt-manganese hydroxide; the complexing agent comprises dimethylamine phosphate and EDTA. The application has excellent synchronous impurity removal and nickel-cobalt-manganese coprecipitation effects for the liquid after iron, aluminum and chromium are removed and prepared from laterite nickel ore, and through a two-stage temperature setting mode in the coprecipitation reaction process, the water content of the nickel-cobalt-manganese hydroxide finished product can be effectively inhibited to be lower than 60%.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hydrometallurgy, and particularly relates to an MHP coprecipitation method based on ternary precursor proportioning. BACKGROUND

[0002] Nickel-cobalt-manganese ternary positive electrode material, commonly referred to as lithium nickel cobalt manganese oxide, has a chemical formula of Li(Ni x Co y Mn (1-x-y) )O2, and is a key electrode material in lithium-ion batteries, widely used in electric vehicles, mobile devices, energy storage systems and other fields, especially in power cylindrical lithium-ion batteries. Nickel-cobalt-manganese lithium is widely used due to its high energy density and good performance. Currently, common nickel-cobalt-manganese ternary positive electrode materials (NCM for short) include NCM523, NCM622 and NCM811, and the numbers represent the molar ratio of nickel, cobalt and manganese.

[0003] Nickel-cobalt-manganese ternary positive electrode material is mainly prepared by high-temperature sintering of nickel-cobalt-manganese ternary precursor and lithium salt, so the performance of nickel-cobalt-manganese ternary precursor largely determines the performance of nickel-cobalt-manganese ternary positive electrode material synthesized therefrom. Nickel-cobalt-manganese ternary precursor, commonly referred to as nickel-cobalt-manganese hydroxide, has a chemical formula of (Ni x Co y Mn (1-x-y) (OH)2, and is a key intermediate product for preparing nickel-cobalt-manganese ternary positive electrode material. With the rapid development of new energy vehicles and energy storage and other fields, the market demand for high-performance lithium-ion batteries is increasing, which has driven the development of the nickel-cobalt-manganese ternary precursor market and intensified the market demand for nickel, cobalt and manganese, the raw materials for synthesizing nickel-cobalt-manganese ternary precursor.

[0004] Currently, laterite nickel ore is one of the important sources of nickel, containing a certain amount of cobalt and manganese, and plays a key role in the production process of nickel-cobalt-manganese ternary precursor. Its rich reserves and mineability provide stable raw material supply for the development of the nickel-cobalt-manganese ternary precursor industry. In the existing process, the laterite nickel ore hydrometallurgy process is usually used to extract high-purity nickel, cobalt and manganese salt raw materials required for preparing nickel-cobalt-manganese ternary precursor.

[0005] Due to the difficulty in controlling the full co-precipitation of nickel, cobalt and manganese in the existing MHP (nickel-cobalt hydroxide) precipitation process section of the existing wet process, the nickel-cobalt-manganese hydroxide obtained by precipitation cannot meet the nickel-cobalt-manganese ratio of the ternary precursor to be prepared; at the same time, the nickel-cobalt-manganese hydroxide obtained by the MHP precipitation process section has high impurity content and high water content, which is not conducive to directly using it to prepare the ternary precursor, so that it is necessary to extract nickel, cobalt and manganese after the MHP precipitation process, such as subsequent extraction process, thereby making the existing hydrometallurgical process line relatively long and high in cost. In order to reduce the cost of the existing laterite nickel ore hydrometallurgical process, it is urgent to propose a new process to solve the above problems existing in the existing MHP precipitation process section. SUMMARY

[0006] In view of the problems existing in the prior art, the purpose of the present application is to provide a MHP co-precipitation method based on ternary precursor ratio, which solves the technical problems that the MHP precipitation process section in the prior art is difficult to co-precipitate nickel, cobalt and manganese, and the nickel-cobalt-manganese hydroxide obtained by precipitation can meet the nickel-cobalt-manganese ratio of the ternary precursor to be prepared and has low impurity content.

[0007] To achieve this purpose, the present application adopts the following technical solutions:

[0008] The present application provides a MHP co-precipitation method based on ternary precursor ratio, comprising the following steps: S1, based on the nickel-cobalt-manganese ratio of the ternary precursor to be prepared, adjusting the nickel-cobalt-manganese ratio contained in the iron-aluminum-chromium-removed solution to obtain a concentrated solution which is divided into a first mixed salt solution and a second mixed salt solution; S2, mixing water, ammonia, a precipitant and the first mixed salt solution uniformly to obtain a pre-precipitation solution; S3, synchronously adding the second mixed salt solution, the precipitant and a complexing agent into the pre-precipitation solution to carry out a precipitation reaction to prepare nickel-cobalt-manganese hydroxide; the complexing agent comprises dimethylamine phosphate and EDTA.

[0009] Preferably, in the S1 step, the chemical formula of the ternary precursor to be prepared is Ni x Co y Mn z (OH)2, wherein 0.5≤x<1, 0<y<1, 0<z<1, and x+y+z=1; the nickel-cobalt-manganese ratio can include any one of 5:2:3, 6:2:2, 8:1:1, 9:0.5:0.5, and the nickel-cobalt-manganese ratio of the ternary precursor to be prepared can cover any one of 5-9 ternary precursors; specifically, the nickel-cobalt-removed solution, manganese slag, manganese salt, etc. can be reused as a manganese adjusting agent, and a cobalt salt can be used as a cobalt adjusting agent to adjust the nickel-cobalt-manganese ratio contained in the iron-aluminum-chromium-removed solution, so that the ratio is adapted to the nickel-cobalt-manganese ratio of the subsequent ternary precursor.

[0010] Preferably, the solution after removing iron, aluminum and chromium is a liquid phase obtained by sequentially subjecting laterite nickel ore to high-pressure acid leaching, one-stage removal of iron and aluminum, and two-stage removal of iron and aluminum.

[0011] Preferably, the solution after removing iron, aluminum and chromium contains nickel, cobalt and manganese elements, and contains impurity elements.

[0012] Preferably, the impurity elements include any one or a combination of at least two of magnesium, aluminum, iron, chromium or calcium.

[0013] Preferably, in the S1 step, the concentration of the sum of nickel, cobalt and manganese elements in the first mixed salt solution after concentration is 0.7-1.1 mol / L, and the concentration of the sum of nickel, cobalt and manganese elements in the second mixed salt solution is 0.7-1.1 mol / L.

[0014] Preferably, in the S1 step, the volume ratio of the first mixed salt solution to the second mixed salt solution is 1:(9-20).

[0015] Preferably, in the S2 step, the specific steps of the S2 step are as follows:

[0016] Water, ammonia, and a precipitating agent are added to a reaction kettle to obtain a mixed solution, the pH is adjusted and the temperature is first raised, and then the first mixed salt solution is added to the reaction kettle for pre-reaction to obtain the pre-precipitation solution.

[0017] Preferably, the concentration of the precipitating agent in the mixed solution is 4-10 mol / L.

[0018] Preferably, the concentration of ammonia in the mixed solution is 3-8 mol / L.

[0019] Preferably, the pH is adjusted to 9-11.

[0020] Preferably, the final temperature of the first temperature raising is 60-80°C.

[0021] Preferably, the pre-reaction time is 1-2 h.

[0022] Preferably, the pre-reaction is carried out at the final temperature of the first temperature raising.

[0023] Preferably, EDTA is further added in the pre-reaction.

[0024] Preferably, the concentration of EDTA added in the pre-reaction is 0.01-0.05 mol / L.

[0025] Preferably, in the S2 step, the precipitating agent includes sodium carbonate and / or sodium hydroxide.

[0026] Preferably, the specific steps of the S3 step are as follows:

[0027] The second mixed salt solution, the solution of the precipitant and the solution of the complexing agent are synchronously added to the pre-precipitation liquid at a preset flow rate to carry out a preliminary co-precipitation reaction, and the pH value is maintained in a preset pH range during the preliminary co-precipitation reaction. Then, the second temperature is raised, and the second mixed salt solution and the precipitant continue to be added while the pH value is maintained in the preset pH range, and the co-precipitation reaction is continued to prepare the nickel-cobalt-manganese hydroxide.

[0028] Preferably, the preset pH range is 7.5-8.0.

[0029] Preferably, the temperature of the preliminary co-precipitation reaction is 50-70℃ and does not exceed 70℃.

[0030] Preferably, the second mixed salt solution, the solution of the precipitant and the solution of the complexing agent are synchronously added for 2-4h.

[0031] Preferably, the final temperature of the second temperature rise is 70-90℃.

[0032] Preferably, the rate of the second temperature rise is 2-5℃ / min.

[0033] Preferably, the time for continuing the co-precipitation reaction is 1-2h.

[0034] Preferably, in the S3 step, the flow rate ratio among the second mixed salt solution, the solution of the precipitant and the solution of the complexing agent is (2.6-3.0):1:(0.3-0.5).

[0035] Preferably, in the S3 step, the precipitant comprises sodium carbonate and / or sodium hydroxide.

[0036] Preferably, the concentration of the complexing agent in the solution of the complexing agent is 0.01-0.2mol / L.

[0037] Preferably, the molar ratio of dimethylamine phosphate to EDTA in the complexing agent is 0.4-0.6:1.

[0038] Compared with the prior art, the present application has at least the following beneficial effects:

[0039] The MHP co-precipitation method based on the proportioning of ternary precursors provided by the application configures the mixed salt solution required for MHP precipitation according to the nickel-cobalt-manganese ratio of the ternary precursor to be prepared, and divides the mixed salt solution into two parts, mixes a small part of the mixed salt solution with ammonia water and a precipitating agent to form a pre-precipitation liquid, and pre-generates nickel-cobalt-manganese hydroxide in the pre-precipitation liquid, so that the pre-precipitation liquid can serve as the precipitation basis of nickel-cobalt-manganese hydroxide and promote the subsequent precipitation of nickel-cobalt-manganese hydroxide after being mixed with another mixed salt solution containing more content and a precipitating agent; the introduced complexing agent EDTA can improve the co-precipitation effect of nickel-cobalt-manganese by using the difference in the stability of the complexes of nickel-cobalt-manganese and magnesium under different pH conditions, and reduce the impurity content; meanwhile, the mutual compounding of dimethylamine phosphate can further reduce the impurity content in the nickel-cobalt-manganese precursor; meanwhile, through the two-stage temperature setting mode in the co-precipitation reaction process, the water content of the nickel-cobalt-manganese hydroxide product can be effectively inhibited, so that the water content is less than 60%, the total precipitation rate of nickel-cobalt-manganese is more than 84%, preferably more than 99%, and the purity of the nickel-cobalt-manganese hydroxide is more than 98wt%, preferably more than 99wt%, wherein the Mg content is less than 1wt%, preferably less than 0.1wt%. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 is a process flow chart of an embodiment of the MHP co-precipitation method based on the proportioning of ternary precursors of the application. DETAILED DESCRIPTION

[0041] For the purpose of clarity, the application is described in the following embodiments. It should be understood by those skilled in the art that the embodiments are only used to help understand the application, and should not be regarded as specific limitations on the application.

[0042] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly and specifically limited.

[0043] Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearance of the phrase in various places in the specification does not necessarily all refer to the same embodiment, nor is it necessarily independent or alternative to other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0044] The existing laterite nickel ore hydrometallurgy process flow is: beneficiation-high pressure leaching-CCD countercurrent washing-iron, aluminum and chromium removal-MHP precipitation-tailing treatment. In the MHP precipitation process section, sodium hydroxide is usually added to the iron, aluminum and chromium removal liquid to precipitate nickel and cobalt hydroxide, thereby realizing the enrichment of nickel and cobalt. In the actual MHP precipitation process, the K SP of nickel hydroxide is 2.0x10 -15 , the K SP of cobalt hydroxide is 5.92x10 -15 , the K SP of manganese hydroxide is 1.9x10 -13 , and the K SP of magnesium hydroxide is 1.8x10 -11 . According to the solubility product of the hydroxides of various metals, the K SP of nickel hydroxide and cobalt hydroxide is close, so that they can be preferentially co-precipitated, and then manganese and magnesium are precipitated in turn. Since the solubility product of manganese hydroxide and nickel-cobalt hydroxide differs by two orders of magnitude, it is difficult to realize the co-precipitation of nickel, cobalt and manganese. In view of the existing problems, the present application provides the following solutions.

[0045] The present application provides a MHP co-precipitation method based on ternary precursor ratio, comprising the following steps: S1, based on the nickel, cobalt and manganese ratio of the ternary precursor to be prepared, adjusting the nickel, cobalt and manganese ratio contained in the liquid after iron, aluminum and chromium removal, and obtaining a concentrated liquid which is divided into a first mixed salt solution and a second mixed salt solution; S2, uniformly mixing water, ammonia, a precipitant and the first mixed salt solution to obtain a pre-precipitation liquid; S3, synchronously adding the second mixed salt solution, a precipitant and a complexing agent to the pre-precipitation liquid for precipitation reaction to prepare nickel, cobalt and manganese hydroxide; and the complexing agent comprises dimethylamine phosphate and EDTA.

[0046] Preferably, in the S1 step, the chemical formula of the ternary precursor to be prepared is Ni x Co y Mn z(OH)2, wherein 0.5≤x<1, 0<y<1, 0<z<1, and x+y+z=1; the ratio of nickel, cobalt and manganese can include any one of 5:2:3, 6:2:2, 8:1:1, 9:0.5:0.5, and the nickel, cobalt and manganese ratio of the ternary precursor to be prepared can cover any one of the nickel, cobalt and manganese ratio of the 5-9 series ternary precursor, the value of x can be, for example, 0.5, 0.6, 0.7, 0.8, 0.9, 0.95 or 0.98, etc.; the value of y can be, for example, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 or 0.95, etc.; the value of z can be, for example, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 0.92 or 0.95, etc.; specifically, the nickel, cobalt and manganese ratio of the post-iron, aluminum and chromium removal solution can be adjusted by using the nickel, cobalt and manganese post-liquid, manganese residue, manganese salt, etc. as manganese adjusting agents, and using cobalt salt as a cobalt adjusting agent, so that the ratio is adapted to the nickel, cobalt and manganese ratio of the subsequent ternary precursor.

[0047] Preferably, the post-iron, aluminum and chromium removal solution is a liquid phase obtained by sequentially subjecting a laterite nickel ore to high-pressure acid leaching and one-stage and two-stage iron and aluminum removal.

[0048] Preferably, the post-iron, aluminum and chromium removal solution contains nickel, cobalt and manganese elements, and contains impurity elements.

[0049] Preferably, the impurity elements include any one or a combination of at least two of magnesium, aluminum, iron, chromium or calcium, wherein a typical but non-limiting combination is a combination of magnesium and aluminum, a combination of iron and aluminum, a combination of magnesium and iron, a combination of chromium and aluminum, and a combination of chromium and calcium.

[0050] Preferably, the magnesium content in the post-iron, aluminum and chromium removal solution is 1-9 g / L, which can be, for example, 1 g / L, 1.3 g / L, 1.5 g / L, 1.7 g / L, 1.9 g / L, 2.2 g / L, 2.4 g / L, 2.6 g / L, 2.8 g / L, 3 g / L, 3.5 g / L, 4 g / L, 5 g / L, 8 g / L or 9 g / L, etc., but is not limited to the listed values, and other unlisted values within the range are also applicable.

[0051] Preferably, the aluminum content in the post-iron, aluminum and chromium removal solution is 0.001-0.01 g / L, which can be, for example, 0.001 g / L, 0.002 g / L, 0.003 g / L, 0.005 g / L, 0.008 g / L, 0.009 g / L or 0.01 g / L, etc., but is not limited to the listed values, and other unlisted values within the range are also applicable.

[0052] Preferably, the iron content in the iron-aluminum-chromium-removed solution is 0.0001-0.001 g / L, for example, it can be 0.0001 g / L, 0.0002 g / L, 0.0003 g / L, 0.0004 g / L, 0.0005 g / L, 0.0006 g / L or 0.001 g / L, etc., but not limited to the listed values, other values not listed in this range are also applicable.

[0053] Preferably, the chromium content in the iron-aluminum-chromium-removed solution is 0.001-0.005 g / L, for example, it can be 0.001 g / L, 0.002 g / L, 0.003 g / L, 0.004 g / L or 0.005 g / L, etc., but not limited to the listed values, other values not listed in this range are also applicable.

[0054] Preferably, the calcium content in the iron-aluminum-chromium-removed solution is 0.1-0.5 g / L, for example, it can be 0.1 g / L, 0.12 g / L, 0.13 g / L, 0.14 g / L, 0.15 g / L, 0.2 g / L, 0.25 g / L, 0.3 g / L, 0.35 g / L, 0.4 g / L, 0.45 g / L or 0.5 g / L, etc., but not limited to the listed values, other values not listed in this range are also applicable.

[0055] Preferably, in the S1 step, the concentration of the sum of nickel, cobalt and manganese elements in the first mixed salt solution after concentration is 0.7-1.1 mol / L, and the concentration of the sum of nickel, cobalt and manganese elements in the second mixed salt solution is 0.7-1.1 mol / L, specifically, the concentration of the sum of nickel, cobalt and manganese elements in the first mixed salt solution and the second mixed salt solution after concentration is independently 0.7 mol / L, 0.8 mol / L, 0.9 mol / L, 1.0 mol / L, 1.1 mol / L or other values in this range.

[0056] Preferably, in the S1 step, the volume ratio of the first mixed salt solution to the second mixed salt solution is 1:(9-20), for example, it can be 1:9, 1:10, 1:11, 1:12, 1:13, 1:14, 1:15, 1:16, 1:17, 1:18, 1:19 or 1:20, etc. For the distribution of mixed salt solution, only a small part of the total amount is taken as the first mixed salt solution and used to prepare the pre-precipitation solution, so that the small amount of pre-formed nickel-cobalt-manganese hydroxide can promote the subsequent reaction settlement without affecting the subsequent nickel-cobalt-manganese hydroxide settlement ratio.

[0057] Preferably, in the S2 step, the specific steps of the S2 step are as follows: water, ammonia water and precipitant are added to the reaction kettle to obtain a mixed solution, the pH is adjusted and the first temperature is raised, then the first mixed salt solution is added to the reaction kettle for pre-reaction to obtain the pre-precipitation solution.

[0058] Preferably, the concentration of the precipitant in the mixed solution is 4-10 mol / L, for example, it can be 4 mol / L, 4.7 mol / L, 5.4 mol / L, 6 mol / L, 6.7 mol / L, 7.4 mol / L, 8 mol / L, 8.7 mol / L, 9.4 mol / L or 10 mol / L, etc., but not limited to the listed values, other values not listed in this range are also applicable.

[0059] Preferably, the concentration of ammonia in the mixed solution is 3-8 mol / L, for example, it can be 3 mol / L, 3.6 mol / L, 4.2 mol / L, 4.7 mol / L, 5.3 mol / L, 5.8 mol / L, 6.4 mol / L, 6.9 mol / L, 7.5 mol / L or 8 mol / L, etc., but not limited to the listed values, other values not listed in this range are also applicable.

[0060] Preferably, the pH is adjusted to 9-11, for example, it can be 9, 9.3, 9.5, 9.7, 9.9, 10.2, 10.4, 10.6, 10.8 or 11, etc., but not limited to the listed values, other values not listed in this range are also applicable.

[0061] Preferably, the final temperature of the first temperature rise is 60-80℃, for example, it can be 60℃, 63℃, 65℃, 67℃, 69℃, 72℃, 74℃, 76℃, 78℃ or 80℃, etc., but not limited to the listed values, other values not listed in this range are also applicable.

[0062] Preferably, the pre-reaction time is 1-2 h, for example, it can be 1 h, 1.2 h, 1.3 h, 1.4 h, 1.5 h, 1.6 h, 1.7 h, 1.8 h, 1.9 h or 2 h, etc., but not limited to the listed values, other values not listed in this range are also applicable.

[0063] Preferably, the pre-reaction is carried out at the final temperature of the first temperature rise.

[0064] Preferably, EDTA is also added in the pre-reaction.

[0065] Preferably, the concentration of EDTA added in the pre-reaction is 0.01-0.05 mol / L, for example, it can be 0.01 mol / L, 0.015 mol / L, 0.02 mol / L, 0.03 mol / L, 0.04 mol / L or 0.05 mol / L, etc.

[0066] Preferably, in the S2 step, the precipitant includes sodium carbonate and / or sodium hydroxide.

[0067] Preferably, the specific steps of the S3 step are as follows:

[0068] The second mixed salt solution, the solution of the precipitant and the solution of the complexing agent are synchronously added to the pre-precipitation liquid at a preset flow rate to carry out a preliminary co-precipitation reaction, and the pH value is maintained in a preset pH range during the preliminary co-precipitation reaction; then the second temperature rising is carried out, and the second mixed salt solution and the precipitant continue to be added while the pH value is maintained in the preset pH range, and the co-precipitation reaction is continued to prepare the nickel-cobalt-manganese hydroxide.

[0069] Preferably, the preset pH range is 7.5-8.0, for example, it can be 7.5, 7.6, 7.7, 7.8, 7.9 or 8.0, etc.

[0070] Preferably, the temperature of the preliminary co-precipitation reaction is 50-70°C and does not contain 70°C, for example, it can be 50°C, 53°C, 55°C, 57°C, 59°C, 62°C, 64°C, 66°C, 68°C or 69°C, etc., but is not limited to the listed values, and other values not listed in this range are also applicable.

[0071] Preferably, the time length of the synchronous addition of the second mixed salt solution, the solution of the precipitant and the solution of the complexing agent is 2-4h, for example, it can be 2h, 2.3h, 2.5h, 2.7h, 2.9h, 3.2h, 3.4h, 3.6h, 3.8h or 4h, etc., but is not limited to the listed values, and other values not listed in this range are also applicable.

[0072] Preferably, the final temperature of the second temperature rising is 70-90°C, for example, it can be 70°C, 73°C, 75°C, 77°C, 79°C, 82°C, 84°C, 86°C, 88°C or 90°C, etc., but is not limited to the listed values, and other values not listed in this range are also applicable.

[0073] Preferably, the rate of the second temperature rising is 2-5°C / min, for example, it can be 2°C / min, 2.2°C / min, 2.3°C / min, 2.4°C / min, 2.5°C / min, 2.6°C / min, 2.7°C / min, 3.0°C / min, 3.2°C / min, 3.5°C / min, 3.8°C / min, 4.0°C / min, 4.2°C / min, 4.5°C / min or 5°C / min, etc., but is not limited to the listed values, and other values not listed in this range are also applicable.

[0074] Preferably, the duration of the continued maintenance of the co-precipitation reaction is 1-2 hours, for example, it can be 1 hour, 1.2 hours, 1.3 hours, 1.4 hours, 1.5 hours, 1.6 hours, 1.7 hours, 1.8 hours, 1.9 hours, or 2 hours, etc., but not limited to the listed values, other values not listed in this range are also applicable.

[0075] Preferably, in the S3 step, the flow rate ratio between the second mixed salt solution, the solution of the precipitant, and the solution of the complexing agent is (2.6-3.0):1:(0.3-0.5). The flow rate of the three controls the ratio of the raw materials. Among them, the proportion of the second mixed salt solution is 2.6, 2.7, 2.8, 2.9, or 3.0, etc.; the proportion of the complexing agent is 0.3, 0.31, 0.32, 0.33, 0.34, 0.35, 0.4, 0.42, 0.45, 0.48, or 0.5, etc.

[0076] Preferably, in the S3 step, the precipitant includes sodium carbonate and / or sodium hydroxide.

[0077] Preferably, in the S3 step, the concentration of the precipitant in the solution of the precipitant is 4-10 mol / L, for example, it can be 4 mol / L, 4.5 mol / L, 5 mol / L, 5.5 mol / L, 6 mol / L, 6.5 mol / L, 7 mol / L, 7.5 mol / L, 8 mol / L, 8.5 mol / L, 9 mol / L, 9.5 mol / L, or 10 mol / L, etc.

[0078] Preferably, the concentration of the complexing agent in the solution of the complexing agent is 0.01-0.2 mol / L, for example, it can be 0.01 mol / L, 0.02 mol / L, 0.03 mol / L, 0.04 mol / L, 0.05 mol / L, 0.06 mol / L, 0.07 mol / L, 0.08 mol / L, 0.09 mol / L, 0.1 mol / L, 0.12 mol / L, 0.13 mol / L, 0.15 mol / L, 0.18 mol / L, or 0.2 mol / L, etc.

[0079] Preferably, the molar ratio of dimethylamine phosphate and EDTA in the complexing agent is 0.4-0.6:1, for example, it can be 0.4:1, 0.42:1, 0.45:1, 0.48:1, 0.50:1, 0.55:1, 0.58:1, or 0.6:1, etc.

[0080] In the present application, MHP co-precipitation refers to Mixed Hydroxide Precipitate co-precipitation, that is, a chemical reaction in which multiple solutes are precipitated from a solution through a co-precipitation process.

[0081] The MHP co-precipitation method based on the proportion of ternary precursors provided by the application has the following mechanism:

[0082] 1) The pre-precipitation is firstly prepared to prepare a pre-precipitation liquid, and then the co-precipitation reaction is performed, which is because the impurity elements are contained in the liquid after removing iron, aluminum and chromium, and the impurity elements are easy to be entrained or synchronously precipitated in the MHP co-precipitation reaction process, thereby reducing the purity of the ternary precursor; by performing the pre-precipitation first, the ternary precursor crystal nucleus is formed first, so that the co-precipitation of nickel, cobalt and manganese is more favorable in the subsequent co-precipitation reaction process, the complexation of EDTA and dimethylamine phosphate to nickel, cobalt and manganese is avoided, not only the precipitation of impurity elements can be avoided, but also the element proportion of the ternary precursor can be effectively controlled.

[0083] 2) The application further preferably adds EDTA in the pre-precipitation step, as described above, the pre-precipitation step is to prepare the ternary precursor crystal nucleus, in order to avoid the impurities entrained in the crystal nucleus, a small amount of EDTA is added in the pre-precipitation process, and the pH is controlled to be slightly high, under the pH condition, the small amount of EDTA is preferentially complexed with Ca and Mg in the system, thereby favoring to ensure the purity of the final ternary precursor.

[0084] 3) In the process of coprecipitation reaction, EDTA and dimethylamine phosphate are introduced as complexing agents. On the one hand, from the stability constant LgK of different metal ions and complexing agents, the LgK of nickel ion is 18.56, the LgK of cobalt ion is 16.21, the LgK of manganese ion is 13.98, and the LgK of magnesium ion is 8.69. The LgK of nickel, cobalt and manganese is relatively close and is quite different from the LgK of magnesium. Since the impurities in the system during the coprecipitation reaction are mainly magnesium, the difference in stability between the complexing agents and nickel, cobalt, manganese and magnesium can be used to realize the preferential complexation of nickel, cobalt and manganese, thereby promoting the coprecipitation of nickel, cobalt and manganese. On the other hand, the complexing capacity of different metal ions also has a pH range suitable therefor. It has been verified through experiments that the suitable pH range for EDTA to complex magnesium ions is 9-11, while the pH of the coprecipitation reaction is controlled to be 7.5-8.0 in the present application, so that the pH condition is more suitable for the complexation of nickel, cobalt and manganese and is not suitable for the complexation of magnesium, thereby further promoting the stability of the complexation of nickel, cobalt and manganese. At the same time, dimethylamine phosphate is synchronously added. Dimethylamine phosphate can be well complexed with Mg and Ca elements in the pH range of 7.0-8.0 and has a weak complexing capacity for nickel, cobalt and manganese. In the process of coprecipitation reaction, dimethylamine phosphate is complexed with impurity elements such as Mg and Ca to avoid the entrainment of impurity elements into the ternary precursor precipitate, thereby significantly improving the purity of the ternary precursor. That is, two different complexing agents are used in the present application to complex nickel, cobalt and manganese and impurity elements, respectively. Moreover, the temperature has a significant effect on the complexing activity of EDTA. During the addition of the complexing agent, the temperature condition suitable for complexation is maintained, so that the complexing agent can be well complexed with nickel, cobalt and manganese. The temperature of the coprecipitation reaction is increased to be higher than the optimal temperature condition for the complexation of EDTA and nickel, cobalt and manganese ions, thereby inhibiting the complexation degree and the crystal water of the complex, so that the water content of the final nickel, cobalt and manganese hydroxide product is not too high.

[0085] 4) Since the complexing capacity of EDTA is different under different pH conditions, EDTA is first complexed with trace impurity elements in the pre-precipitation solution to inhibit the impurities in the crystal nucleus of the ternary precursor. When entering the coprecipitation reaction, the EDTA and impurity elements are released with the change of pH condition. Since the impurity elements have not reached the precipitation solubility product and the pH condition, the impurity elements are released into the solution and are complexed with dimethylamine phosphate, while EDTA is complexed with nickel, cobalt and manganese, thereby realizing the separation of impurity elements and nickel, cobalt and manganese in the coprecipitation reaction and obtaining a ternary precursor with high purity and low water content.

[0086] The present application is further described in detail through specific examples. To avoid redundancy, the liquid after removing iron and aluminum from the laterite nickel ore used in the examples and comparative examples is described as follows:

[0087] The post-iron and aluminum removal liquid of the laterite nickel ore used in the present application is a liquid phase obtained after high-pressure acid leaching-one-stage iron and aluminum removal-two-stage iron and aluminum removal of the laterite nickel ore, wherein the main components are shown in Table 1 in g / L.

[0088] Table 1

[0089] Ni Co Mn Fe Al Cr Cu Ca Mg 3.33 0.32 1.99 0.0004 0.005 0.0025 0.007 0.45 5.32

[0090] Example 1

[0091] The present embodiment provides a MHP co-precipitation method based on the proportioning of ternary precursors, which comprises the following steps: Figure 1

[0092] (1) Based on the mass ratio of nickel, cobalt and manganese of 5:2:3 of the ternary precursor to be prepared, the proportion of nickel, cobalt and manganese contained in the post-iron and aluminum removal liquid is adjusted (additional addition of nickel salt, cobalt salt or manganese salt), and after concentration, it is divided into a first mixed salt solution and a second mixed salt solution in a ratio of 1:20. The concentration of the sum of nickel, cobalt and manganese elements in the first mixed salt solution is 0.8 mol / L, and the concentration of the sum of nickel, cobalt and manganese elements in the second mixed salt solution is 0.8 mol / L.

[0093] (2) Water, ammonia water with a concentration of 4 mol / L and sodium hydroxide solution with a concentration of 5 mol / L are added to the reaction kettle to obtain a mixed solution, the pH is adjusted to 9 and the first temperature is raised to 60℃, then EDTA and the first mixed salt solution are added to the reaction kettle for pre-reaction. The concentration of EDTA in the pre-reaction system is 0.03 mol / L, and the pre-precipitation reaction is carried out at a pH of 9 and a temperature of 60℃ for 1 h to obtain a pre-precipitation liquid.

[0094] (3) A solution containing 0.02 mol / L EDTA and 0.01 mol / L dimethylamine phosphate (solvent is water) is taken as a complexing agent, the second mixed salt solution, the sodium hydroxide solution with a concentration of 5 mol / L and the solution of the complexing agent are synchronously added to the pre-precipitation liquid at a flow rate ratio of 2.6:1:0.3, and a preliminary co-precipitation reaction is carried out at a pH of 7.5 and a temperature of 50℃ for 4 h; then the temperature is rapidly raised to 90℃ at a speed of 5℃ / min, the second mixed salt solution and the sodium hydroxide solution continue to be added at the same speed, the pH is maintained at 7.5, and the co-precipitation reaction is continued for 1 h, and the obtained co-precipitation reaction material is filtered to obtain a nickel-cobalt-manganese hydroxide finished product.

[0095] Example 2

[0096] The present embodiment provides a MHP co-precipitation method based on the proportioning of ternary precursors, which comprises the following steps:

[0097] ​(1) Based on the mass ratio of nickel, cobalt and manganese in the ternary precursor to be prepared 6:2:2, the ratio of nickel, cobalt and manganese in the solution after removing iron, aluminum and chromium is adjusted (additional nickel salt, cobalt salt or manganese salt is added), and after concentration, it is divided into a first mixed salt solution and a second mixed salt solution in a ratio of 1:15, the concentration of the sum of nickel, cobalt and manganese in the first mixed salt solution is 0.7 mol / L, and the concentration of the sum of nickel, cobalt and manganese in the second mixed salt solution is 0.7 mol / L.

[0098] (2) Water, ammonia water with a concentration of 3 mol / L, and sodium hydroxide solution with a concentration of 4 mol / L are added to the reaction kettle to obtain a mixed solution, the pH is adjusted to 10 and the first temperature is raised to 70℃, then EDTA and the first mixed salt solution are added to the reaction kettle for pre-reaction, the concentration of EDTA in the pre-reaction system is 0.04 mol / L, the pre-precipitation reaction is carried out at pH 10 and temperature 70℃ for 50 min, and the pre-precipitation solution is obtained.

[0099] (3) Take a solution (solvent is water) containing 0.01 mol / L EDTA and 0.004 mol / L dimethylamine phosphate as a complexing agent, and the second mixed salt solution, sodium hydroxide solution with a concentration of 4 mol / L and the solution of the complexing agent are synchronously added to the pre-precipitation solution at a flow rate ratio of 2.8:1:0.4, and the preliminary co-precipitation reaction is carried out at pH 8.0 and temperature 60℃ for 2h; then the temperature is raised to 70℃ at a rate of 2℃ / min, the second mixed salt solution and sodium hydroxide solution continue to be added at the same speed, the pH is maintained at 8.0, and the co-precipitation reaction is continued for 1.5h, and the co-precipitation reaction material obtained is filtered to obtain nickel-cobalt-manganese hydroxide finished product.

[0100] Example 3

[0101] The embodiment provides a MHP co-precipitation method based on ternary precursor ratio, and the MHP co-precipitation method comprises the following steps:

[0102] (1) Based on the mass ratio of nickel, cobalt and manganese in the ternary precursor to be prepared 6:2:2, the ratio of nickel, cobalt and manganese in the solution after removing iron, aluminum and chromium is adjusted (additional nickel salt, cobalt salt or manganese salt is added), and after concentration, it is divided into a first mixed salt solution and a second mixed salt solution in a ratio of 1:15, the concentration of the sum of nickel, cobalt and manganese in the first mixed salt solution is 0.7 mol / L, and the concentration of the sum of nickel, cobalt and manganese in the second mixed salt solution is 0.7 mol / L.

[0103] (2) adding water, ammonia water with a concentration of 7 mol / L, and sodium hydroxide solution with a concentration of 5 mol / L into a reaction kettle to obtain a mixed solution, adjusting the pH to 10.5 and first heating to 70°C, then adding EDTA and the first mixed salt solution into the reaction kettle for pre-reaction, the concentration of EDTA in the pre-reaction system being 0.05 mol / L, the pre-precipitation reaction being carried out at a pH of 10.5 and a temperature of 70°C for 1 h to obtain a pre-precipitation solution.

[0104] (3) taking a solution of a complexing agent containing 0.05 mol / L EDTA and 0.025 mol / L dimethylamine phosphate (the solvent being water), synchronously adding the second mixed salt solution, sodium hydroxide solution with a concentration of 5.5 mol / L, and the solution of the complexing agent into the pre-precipitation solution at a flow rate ratio of 2.9:1:0.3, carrying out a preliminary co-precipitation reaction at a pH of 8.0 and a temperature of 60°C for 4 h, then rapidly heating to 90°C at a speed of 3°C / min, continuously adding the second mixed salt solution and the sodium hydroxide solution at the same speed, maintaining the pH at 8.0, and continuing the co-precipitation reaction for 2 h, to obtain a co-precipitation reaction material, which is filtered to obtain a nickel-cobalt-manganese hydroxide product.

[0105] Example 4

[0106] The embodiment provides a MHP co-precipitation method based on a ternary precursor ratio, and the MHP co-precipitation method comprises the following steps:

[0107] (1) based on the mass ratio of nickel-cobalt-manganese in the ternary precursor to be prepared being 9:0.5:0.5, adjusting the nickel-cobalt-manganese ratio contained in the iron-aluminum-chromium-removed liquid (extra adding nickel salt, cobalt salt or manganese salt), and after concentration, being divided into a first mixed salt solution and a second mixed salt solution at a ratio of 1:9, the concentration of the sum of nickel-cobalt-manganese elements in the first mixed salt solution being 1.1 mol / L, and the concentration of the sum of nickel-cobalt-manganese elements in the second mixed salt solution being 1.1 mol / L.

[0108] (2) adding water, ammonia water with a concentration of 8 mol / L, and sodium hydroxide solution with a concentration of 10 mol / L into a reaction kettle to obtain a mixed solution, adjusting the pH to 11 and first heating to 80°C, then adding EDTA and the first mixed salt solution into the reaction kettle for pre-reaction, the concentration of EDTA in the pre-reaction system being 0.01 mol / L, the pre-precipitation reaction being carried out at a pH of 11 and a temperature of 80°C for 1.5 h to obtain a pre-precipitation solution.

[0109] (3) Take the complexing agent solution (solvent is water) with the concentration of 0.1 mol / L EDTA and 0.06 mol / L dimethylamine phosphate, and synchronously add the second mixed salt solution, the sodium hydroxide solution with the concentration of 10 mol / L and the complexing agent solution into the pre-precipitation liquid at the flow rate ratio of 3.0:1:0.5, and carry out the preliminary co-precipitation reaction at the pH value of 8.5 and the temperature of 70℃ for 3h; then rapidly increase the temperature to 80℃ at the speed of 2.5℃ / min, and continuously add the second mixed salt solution and the sodium hydroxide solution at the same speed, maintain the pH value at 8.5, and continue to maintain the co-precipitation reaction for 2h, so as to obtain the nickel-cobalt-manganese hydroxide product after filtration.

[0110] Example 5

[0111] The embodiment provides a MHP co-precipitation method based on ternary precursor proportioning, which is the same as example 1 except that no EDTA is added in step (2), and details are not repeated here.

[0112] Example 6

[0113] The embodiment provides a MHP co-precipitation method based on ternary precursor proportioning, which is the same as example 1 except that 0.02 mol / L dimethylamine phosphate is added in step (3), and details are not repeated here.

[0114] Example 7

[0115] The embodiment provides a MHP co-precipitation method based on ternary precursor proportioning, which is the same as example 1 except that 0.005 mol / L dimethylamine phosphate is added in step (3), and details are not repeated here.

[0116] Example 8

[0117] The embodiment provides a MHP co-precipitation method based on ternary precursor proportioning, which is the same as example 1 except that the temperature of the co-precipitation reaction is maintained at 50℃ in step (3), and details are not repeated here.

[0118] Example 9

[0119] The embodiment provides a MHP co-precipitation method based on ternary precursor proportioning, which is the same as example 1 except that the temperature of the preliminary co-precipitation reaction is 90℃ in step (3), and details are not repeated here.

[0120] Example 10

[0121] The embodiment provides a MHP co-precipitation method based on ternary precursor proportioning, which is the same as the MHP co-precipitation method in the embodiment 1 except that the pH of the initial co-precipitation reaction and the pH of the continued co-precipitation reaction in step (3) are both 9.5.

[0122] Comparative example 1

[0123] The comparative example provides a MHP co-precipitation method based on ternary precursor proportioning, which is the same as the MHP co-precipitation method in the embodiment 1 except that step (2) is not performed, and all the mixed salt solutions are directly subjected to step (3).

[0124] Comparative example 2

[0125] The comparative example provides a MHP co-precipitation method based on ternary precursor proportioning, which is the same as the MHP co-precipitation method in the embodiment 1 except that EDTA is not added in step (3).

[0126] Comparative example 3

[0127] The comparative example provides a MHP co-precipitation method based on ternary precursor proportioning, which is the same as the MHP co-precipitation method in the embodiment 1 except that dimethylamine phosphate is not added in step (3).

[0128] Comparative example 4

[0129] The comparative example provides a MHP co-precipitation method based on ternary precursor proportioning, which is the same as the MHP co-precipitation method in the embodiment 1 except that dimethylamine phosphate is replaced by citric acid in step (3).

[0130] The molar ratio of nickel, cobalt and manganese of the prepared nickel-cobalt-manganese hydroxide finished product in the embodiment 1 to the embodiment 10 and the comparative example 1 to the comparative example 4, the purity of the nickel-cobalt-manganese hydroxide, the mass fraction of magnesium and the water content are tested, and the specific embodiments are shown in Table 2.

[0131] Table 2

[0132]

[0133]

[0134] It can be seen from Table 2 that:

[0135] From Examples 1-4, it can be seen that the prepared nickel-cobalt-manganese hydroxide product is very close to the initial nickel-cobalt-manganese substance molar ratio of the ternary precursor to be prepared, proving that the MHP coprecipitation method based on the ternary precursor ratio described in the present application can well realize the coprecipitation of nickel-cobalt-manganese; at the same time, the magnesium impurity content is low, the water content can be controlled within the level of less than 60%, the total precipitation rate of nickel-cobalt-manganese is above 99%, and the purity of nickel-cobalt-manganese hydroxide is above 99.4wt%, wherein the Mg content is less than 0.1wt%.

[0136] From the comparison of Test Example 1 and Examples 5 and 2, it can be seen that the addition of EDTA in steps (2) and (3) is more conducive to improving the precipitation rate of nickel-cobalt-manganese, and the molar ratio of nickel-cobalt-manganese is closer to the expected value, and the impurity content of Mg in the final product is lower.

[0137] From the comparison of Test Example 1 and Examples 6-7, it can be seen that the present application preferably controls the molar ratio of dimethylamine phosphate to EDTA in step (3) within a reasonable range, which is more conducive to reducing the impurity content of nickel-cobalt-manganese hydroxide and ensuring the precipitation rate of nickel-cobalt-manganese.

[0138] From the comparison of Test Example 1 and Example 8, it can be seen that Example 8 does not set the temperature after adding the complexing agent relative to Example 1, which makes it difficult to inhibit the complexing process of EDTA in the latter stage of the reaction process, resulting in a significant increase in the water content of the final nickel-cobalt-manganese hydroxide product.

[0139] From the comparison of the nickel-cobalt-manganese hydroxide products prepared in Test Example 1 and Example 9, the total precipitation rate of Example 9 is significantly lower than that of Example 1, indicating that the reaction temperature is increased in the preliminary coprecipitation reaction process of Example 9, which makes the temperature condition exceed the suitable complexing range of EDTA for nickel-cobalt-manganese, reducing the degree of complexation of EDTA for nickel-cobalt-manganese, and thus reducing the precipitation rate of nickel-cobalt-manganese.

[0140] From the comparison of Test Example 1 and Example 10, it can be seen that the increase of pH in the complexing reaction process of Example 10 reduces the degree of complexation of EDTA for nickel-cobalt-manganese, while the degree of complexation with magnesium is increased, resulting in fluctuations in the molar ratio of nickel-cobalt-manganese and a significant increase in the magnesium impurity content.

[0141] From the comparison of the nickel-cobalt-manganese hydroxide products prepared in Test Example 1 and Comparative Example 1, the total precipitation rate of Comparative Example 1 is reduced to 78.5% relative to Example 1, proving that the introduction of pre-precipitation liquid in the complexing reaction process will reduce the precipitation rate of nickel-cobalt-manganese.

[0142] As can be seen from Comparative Example 1 and Comparative Examples 3-4, the application selected dimethylamine phosphate and EDTA for compounding use, which can further reduce the Mg impurity content in the nickel-cobalt-manganese hydroxide, and improve the precipitation rate of nickel-cobalt-manganese while ensuring the purity of the nickel-cobalt-manganese hydroxide.

[0143] The application is described in detail by the above examples, but the application is not limited to the above detailed features, that is, it does not mean that the application must rely on the above detailed features to be implemented. It should be understood by those skilled in the art that any improvement of the application, equivalent replacement of the selected technical features of the application, addition of auxiliary technical features, selection of specific modes, etc. fall within the protection scope and disclosure scope of the application.

Claims

1. A method for MHP coprecipitation based on ternary precursor ratios, characterized in that, Includes the following steps: S1, based on the nickel-cobalt-manganese ratio of the ternary precursor to be prepared, the nickel-cobalt-manganese ratio in the solution after removing iron, aluminum, and chromium is adjusted, and the resulting concentrated solution is divided into a first mixed salt solution and a second mixed salt solution. S2, mix water, ammonia, precipitant and the first mixed salt solution evenly to obtain a preprecipitate; S3, the second mixed salt solution, precipitant and complexing agent are simultaneously added to the preprecipitate to carry out a precipitation reaction to prepare nickel cobalt manganese hydroxide; The complexing agent includes dimethylamine phosphate and EDTA; The specific steps of step S3 are as follows: The second mixed salt solution, the precipitant solution, and the complexing agent solution are simultaneously added to the preprecipitate at a preset flow rate to carry out a preliminary coprecipitation reaction, and the pH value is maintained within a preset pH range during the preliminary coprecipitation reaction. Then, the temperature is increased a second time, and the second mixed salt solution and precipitant are continuously added while the pH value is maintained within the preset pH range to continue the co-precipitation reaction and prepare nickel cobalt manganese hydroxide. The preset pH range is 7.5~8.0; the initial coprecipitation reaction temperature is 50~70℃ (excluding 70℃), and the final temperature of the second heating is 70~90℃. The concentration of the complexing agent in the solution is 0.01~0.2 mol / L; the molar ratio of dimethylamine phosphate to EDTA in the complexing agent is 0.4~0.6:1; The liquid after removing iron, aluminum, and chromium contains nickel, cobalt, and manganese, and also contains impurity elements. The impurity elements include magnesium and calcium.

2. The MHP coprecipitation method based on ternary precursor ratio according to claim 1, characterized in that, In the step S1, the chemical formula of the ternary precursor to be prepared is Ni x Co y Mn z (OH)2, where 0.5 ≤ x < 1, 0 < y < 1, 0 < z < 1, and x + y + z = 1.

3. The MHP coprecipitation method based on ternary precursor ratio according to claim 1, characterized in that, The liquid phase obtained after removing iron, aluminum, and chromium is a liquid phase obtained from laterite nickel ore after it has undergone high-pressure acid leaching, a first-stage iron and aluminum removal process, and a second-stage iron and aluminum removal process.

4. The MHP coprecipitation method based on ternary precursor ratio according to claim 1 or 2, characterized in that, In step S1, the concentration of the sum of nickel, cobalt, and manganese elements in the first mixed salt solution after concentration is 0.7~1.1 mol / L, and the concentration of the sum of nickel, cobalt, and manganese elements in the second mixed salt solution is 0.7~1.1 mol / L.

5. The MHP coprecipitation method based on ternary precursor ratio according to claim 4, characterized in that, In step S1, the volume ratio of the first mixed salt solution to the second mixed salt solution is 1:(9~20).

6. The MHP coprecipitation method based on ternary precursor ratio according to claim 1, characterized in that, In step S2, the specific steps are as follows: Water, ammonia, and a precipitant are added to a reaction vessel to obtain a mixed solution. The pH is adjusted and the temperature is raised for the first time. Then, the first mixed salt solution is added to the reaction vessel for pre-reaction to obtain the pre-precipitated solution.

7. The MHP coprecipitation method based on ternary precursor ratio according to claim 6, characterized in that, The concentration of the precipitant in the mixture is 4~10 mol / L.

8. The MHP coprecipitation method based on ternary precursor ratio according to claim 6, characterized in that, The concentration of ammonia in the mixture is 3~8 mol / L.

9. The MHP coprecipitation method based on ternary precursor ratio according to claim 6, characterized in that, The pH is adjusted to 9-11.

10. The MHP coprecipitation method based on ternary precursor ratio according to claim 6, characterized in that, The final temperature of the first heating is 60~80℃.

11. The MHP coprecipitation method based on ternary precursor ratio according to claim 6, characterized in that, The pre-reaction time is 1-2 hours.

12. The MHP coprecipitation method based on ternary precursor ratio according to claim 10, characterized in that, The pre-reaction is carried out at the final temperature condition of the first heating.

13. The MHP coprecipitation method based on ternary precursor ratio according to claim 6, characterized in that, EDTA is also added to the pre-reaction process.

14. The MHP coprecipitation method based on ternary precursor ratio according to claim 13, characterized in that, The concentration of EDTA added in the pre-reaction is 0.01~0.05 mol / L.

15. The MHP coprecipitation method based on ternary precursor ratio according to claim 6, characterized in that, In step S2, the precipitant includes sodium carbonate and / or sodium hydroxide.

16. The MHP coprecipitation method based on ternary precursor ratio according to claim 1, characterized in that, In step S3, the second mixed salt solution, the precipitant solution, and the complexing agent solution are added simultaneously for 2-4 hours.

17. The MHP coprecipitation method based on ternary precursor ratio according to claim 1, characterized in that, The second heating rate is 2~5℃ / min.

18. The MHP coprecipitation method based on ternary precursor ratio according to claim 1, characterized in that, The coprecipitation reaction is maintained for 1-2 hours.

19. The MHP coprecipitation method based on ternary precursor ratio according to claim 1, characterized in that, In step S3, the flow rate ratio between the second mixed salt solution, the precipitant solution, and the complexing agent solution is (2.6~3.0):1:(0.3~0.5).

20. The MHP coprecipitation method based on ternary precursor ratio according to claim 1, characterized in that, In step S3, the precipitant includes sodium carbonate and / or sodium hydroxide.

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