MHP coprecipitation method based on ternary precursor ratio

Abstract

The invention provides an MHP coprecipitation method based on a ternary precursor ratio, and relates to the technical field of hydrometallurgy, and the MHP coprecipitation method 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 an iron-aluminum-chromium-removed solution, and distributing the obtained concentrated solution into a first mixed salt solution and a second mixed salt solution; s2, uniformly mixing water, ammonia water, a precipitator and the first mixed salt solution to obtain a pre-precipitation solution; s3, synchronously adding the second mixed salt solution, a precipitator and a complexing agent into the pre-precipitation solution for precipitation reaction to prepare nickel-cobalt-manganese hydroxide; the complexing agent comprises dimethylamine phosphate and EDTA (ethylene diamine tetraacetic acid). The iron, aluminum and chromium removed liquid prepared for laterite-nickel ore has excellent synchronous impurity removal and nickel-cobalt-manganese co-precipitation effects, and in the co-precipitation reaction process, through a two-stage temperature setting mode, the water content of the nickel-cobalt-manganese hydroxide finished product can be effectively inhibited, and the water content is made to be lower than 60%.

Description

Technical Field

[0001] The invention relates to the technical field of hydrometallurgy, and in particular to a MHP co-precipitation method based on a ternary precursor ratio. Background Art

[0002] Nickel-cobalt-manganese ternary positive electrode material, usually refers to lithium nickel-cobalt-manganese oxide, with a chemical formula of Li(Ni x Co y Mn (1-x-y) ) 2 , 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 oxide is widely used due to its high energy density and good performance. At present, the common nickel cobalt manganese ternary positive electrode materials (abbreviated as NCM) include NCM523, NCM622 and NCM811, and the numbers represent the molar ratio of nickel, cobalt and manganese.

[0003] Nickel-cobalt-manganese ternary cathode material is mainly made by sintering nickel-cobalt-manganese ternary precursor and lithium salt at high temperature. Therefore, the performance of nickel-cobalt-manganese ternary precursor largely determines the performance of the nickel-cobalt-manganese ternary cathode material synthesized from it. Nickel-cobalt-manganese ternary precursor usually refers to nickel-cobalt-manganese hydroxide, and its chemical formula is (Ni x Co y Mn (1-x-y) (OH) 2 ), is a key intermediate product for the preparation of nickel-cobalt-manganese ternary cathode materials. With the rapid development of new energy vehicles and energy storage, the market demand for high-performance lithium-ion batteries continues to increase, which has promoted the development of the nickel-cobalt-manganese ternary precursor market, and also increased the market demand for nickel, cobalt and manganese, the raw materials for the synthesis of nickel-cobalt-manganese ternary precursors.

[0004] At present, laterite nickel ore is one of the important sources of nickel. It contains a certain amount of cobalt and manganese, and plays a key role in the production process of nickel-cobalt-manganese ternary precursors. Its abundant reserves and exploitability provide a stable supply of raw materials for the development of the nickel-cobalt-manganese ternary precursor industry. In the existing process, laterite nickel ore hydrometallurgical process is usually used to extract high-purity nickel, cobalt, and manganese salt raw materials required for the preparation of nickel-cobalt-manganese ternary precursors.

[0005] In the existing wet process of the MHP (nickel cobalt hydroxide) precipitation process section, it is difficult to control the sufficient coprecipitation of nickel, cobalt, and manganese, so that the nickel cobalt manganese hydroxide obtained by precipitation can meet the nickel cobalt manganese ratio of the ternary precursor to be prepared. At the same time, the nickel cobalt manganese hydroxide obtained in the MHP precipitation process section has a high impurity content and a high moisture content. These factors are not conducive to directly using it as the ternary precursor, so it is necessary to separately extract nickel, cobalt, and manganese after the MHP precipitation process, such as performing an extraction process later. As a result, the existing wet metallurgy process line is relatively long and the cost is high. To reduce the cost of the existing laterite nickel ore wet metallurgy process, it is urgent to propose a new process to solve the above deficiencies existing in the existing MHP precipitation process section. Summary of the Invention

[0006] Aiming at the deficiencies of the existing technology, the purpose of the present invention is to provide an MHP coprecipitation method based on the ratio of the ternary precursor, to solve the technical problems that it is difficult to coprecipitate nickel, cobalt, and manganese in the existing MHP precipitation process section, and to make the nickel cobalt manganese hydroxide obtained by precipitation meet the nickel cobalt manganese ratio of the ternary precursor to be prepared and have a low impurity content.

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

[0008] The present invention provides an MHP coprecipitation method based on the ratio of the ternary precursor, including the following steps: S1, based on the nickel cobalt manganese ratio of the ternary precursor to be prepared, adjust the nickel cobalt manganese ratio contained in the solution after removing iron, aluminum, and chromium, and the obtained concentrated solution is divided into a first mixed salt solution and a second mixed salt solution; S2, mix water, ammonia water, a precipitant, and the first mixed salt solution evenly to obtain a pre-precipitation solution; S3, synchronously add the second mixed salt solution, the precipitant, and a complexing agent to the pre-precipitation solution for a precipitation reaction to prepare nickel cobalt manganese hydroxide; the complexing agent includes dimethylamine phosphate and EDTA.

[0009] Preferably, 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; its 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 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 precipitation solution, manganese slag, manganese salt, etc. can be recycled as manganese regulators, and cobalt salt can be used as a cobalt regulator to adjust the nickel cobalt manganese ratio contained in the solution after removing iron, aluminum, and chromium to make its ratio adapt to the nickel cobalt manganese ratio of the subsequent ternary precursor.

[0010] Preferably, the liquid after iron, aluminum and chromium removal is a liquid phase obtained after laterite nickel ore is subjected to high-pressure acid leaching, first-stage iron and aluminum removal, and second-stage iron and aluminum removal in sequence.

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

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

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

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

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

[0016] Water, ammonia water and a precipitant are added into a reactor to obtain a mixed solution, the pH value is adjusted and the temperature is first increased, and then the first mixed salt solution is added into the reactor for pre-reaction to obtain the pre-precipitation solution.

[0017] Preferably, the concentration of the precipitant in the mixed solution is 4 to 10 mol / L.

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

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

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

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

[0022] Preferably, the pre-reaction is carried out under the final temperature condition of the first heating.

[0023] Preferably, EDTA is also 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 step S2, the precipitating agent comprises sodium carbonate and / or sodium hydroxide.

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

[0027] The second mixed salt solution, the solution of the precipitant and the solution of the complexing agent are added to the pre-precipitation solution 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 temperature is raised for a second time, and the second mixed salt solution and the precipitant are continuously added, the pH value is maintained in a preset pH range, and the co-precipitation reaction is continued to prepare nickel-cobalt-manganese hydroxide.

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

[0029] Preferably, the temperature of the preliminary coprecipitation reaction is 50-70°C but not including 70°C.

[0030] Preferably, the second mixed salt solution, the solution of the precipitant and the solution of the complexing agent are added simultaneously for 2 to 4 hours.

[0031] Preferably, the final temperature of the second heating is 70-90°C.

[0032] Preferably, the second heating rate is 2-5°C / min.

[0033] Preferably, the coprecipitation reaction is continued for 1 to 2 hours.

[0034] Preferably, in the step S3, 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).

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

[0036] Preferably, the concentration of the complexing agent in the complexing agent solution is 0.01-0.2 mol / 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 invention has at least the following beneficial effects:

[0039] The MHP co-precipitation method based on the ternary precursor ratio provided by the present invention configures the mixed salt solution required for MHP precipitation according to the ratio of nickel, cobalt and manganese of the ternary precursor to be prepared, and divides the mixed salt solution into two parts, takes a small part of the mixed salt solution and mixes it with ammonia water and a precipitant to form a pre-precipitation liquid, and nickel, cobalt and manganese hydroxides are pre-generated in the pre-precipitation liquid. After the pre-precipitation liquid is mixed with another mixed salt solution with a larger content and a precipitant, it can be used as a precipitation basis for nickel, cobalt and manganese hydroxides, and promotes the subsequent precipitation of nickel, cobalt and manganese hydroxides; the introduced complexing agent EDTA can utilize metals such as nickel, cobalt, manganese and magnesium under different pH conditions. The difference in complex stability can improve the co-precipitation effect on nickel, cobalt and manganese and reduce the impurity content; at the same time, dimethyl phosphate is added to compound with each other, which can further reduce the impurity content in the nickel, cobalt and manganese precursor; at the same time, the water content of the nickel, cobalt and manganese hydroxide product can be effectively suppressed by setting the two-stage temperature during the co-precipitation reaction, so that the water content is lower than 60%, the total precipitation rate of nickel, cobalt and manganese is higher than 84%, preferably higher than 99%, and the purity of nickel, cobalt and manganese hydroxide is higher than 98wt%, preferably higher than 99wt%, wherein the Mg content is lower than 1wt%, preferably lower than 0.1wt%. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a process flow chart of an embodiment of the MHP co-precipitation method based on a ternary precursor ratio of the present invention. DETAILED DESCRIPTION

[0041] For the convenience of understanding the present invention, the present invention lists the following embodiments. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[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 "multiple" is more than two, unless otherwise clearly and specifically defined.

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

[0044] The existing hydrometallurgical process of laterite nickel ore is: ore dressing - high pressure leaching - CCD countercurrent washing - iron, aluminum and chromium removal - MHP precipitation - tailings treatment. In the MHP precipitation process, sodium hydroxide is usually added to the liquid after iron, aluminum and chromium removal for precipitation to generate nickel and cobalt hydroxide to achieve nickel and cobalt enrichment. In the actual MHP precipitation process, the K content of nickel hydroxide is SP 2.0×10 -15 , cobalt hydroxide is K SP 5.92×10 -15 , K of manganese hydroxide SP 1.9×10 -13 , K of magnesium hydroxide SP 1.8×10 -11 According to the solubility product of various metal hydroxides, K SP Close to each other, so that they can be co-precipitated first, followed by manganese and magnesium. Since the solubility product of manganese hydroxide and nickel cobalt hydroxide differs by two orders of magnitude, it is difficult to achieve co-precipitation of nickel, cobalt and manganese. In view of this existing problem, the present invention proposes the following solution.

[0045] The invention provides an MHP co-precipitation method based on a ternary precursor ratio, comprising the following steps: S1, based on the nickel, cobalt and manganese ratio of a ternary precursor to be prepared, adjusting the nickel, cobalt and manganese ratio contained in a liquid after iron, aluminum and chromium are removed, and the obtained concentrated solution is distributed into a first mixed salt solution and a second mixed salt solution; S2, water, ammonia water, a precipitant and the first mixed salt solution are evenly mixed to obtain a pre-precipitation solution; S3, the second mixed salt solution, a precipitant and a complexing agent are simultaneously added to the pre-precipitation solution to carry out a precipitation reaction, so as to prepare nickel, cobalt and manganese hydroxide; the complexing agent comprises dimethylamine phosphate and EDTA.

[0046] Preferably, in 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; the nickel-cobalt-manganese ratio can include any one of 5:2:3, 6:2:2, 8:1:1, 9:0.5:0.5. The nickel-cobalt-manganese ratio of the ternary precursor to be prepared can cover any nickel-cobalt-manganese ratio of the 5-9 series ternary precursors. 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-depleted solution, manganese slag, manganese salt, etc. can be recycled as manganese regulators, and cobalt salt can be used as a cobalt regulator 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.

[0047] Preferably, the iron-aluminum-chromium-removed solution is a liquid phase obtained by subjecting laterite nickel ore to high-pressure acid leaching, first-stage iron-aluminum removal, and second-stage iron-aluminum removal in sequence.

[0048] Preferably, the iron-aluminum-chromium-removed solution contains nickel, cobalt, and manganese elements, and the iron-aluminum-chromium-removed solution 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. Typical but non-limiting combinations are combinations of magnesium and aluminum, iron and aluminum, magnesium and iron, chromium and aluminum, and chromium and calcium.

[0050] Preferably, the magnesium content in the iron-aluminum-chromium-removed solution is 1-9 g / L, for example, it can be 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 not limited to the listed values. Other unlisted values within this range are equally applicable.

[0051] Preferably, the aluminum content in the iron-aluminum-chromium-removed solution is 0.001-0.01 g / L, for example, it can be 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 not limited to the listed values. Other unlisted values within this range are equally applicable.

[0052] Preferably, the iron content in the iron-aluminum-chromium removal liquid 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, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0053] Preferably, the chromium content in the liquid after iron, aluminum and chromium removal 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, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0054] Preferably, the calcium content in the liquid after iron, aluminum and chromium removal 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, but is not limited to the listed values, and other values ​​not listed in this range are also applicable.

[0055] Preferably, in the 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. 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 are each independently 0.7 mol / L, 0.8 mol / L, 0.9 mol / L, 1.0 mol / L, 1.1 mol / L or other values ​​within the range.

[0056] Preferably, in the step S1, 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 the mixed salt solution, only a small amount of the first mixed salt solution is needed to be used for preparing the pre-precipitation solution, so that the pre-generated small amount of nickel cobalt manganese hydroxide can promote the subsequent reaction sedimentation without affecting the subsequent nickel cobalt manganese hydroxide sedimentation ratio.

[0057] Preferably, in the step S2, the specific steps of the step S2 are as follows: adding water, ammonia water and a precipitant into a reactor to obtain a mixed solution, adjusting the pH and first heating the mixture, and then adding the first mixed salt solution into the reactor for pre-reaction to obtain the pre-precipitation solution.

[0058] Preferably, the concentration of the precipitant in the mixed solution is 4 to 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, but is not limited to the listed values, and other values ​​not listed within the range are also applicable.

[0059] Preferably, the concentration of aqueous ammonia in the mixed solution is 3 to 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, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

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

[0061] Preferably, the final temperature of the first heating is 60-80°C, for example, it can be 60°C, 63°C, 65°C, 67°C, 69°C, 72°C, 74°C, 76°C, 78°C or 80°C, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0062] Preferably, the pre-reaction time is 1 to 2 h, for example, 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, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0063] Preferably, the pre-reaction is carried out under the final temperature condition of the first heating.

[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, 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.

[0066] Preferably, in the step S2, the precipitating agent comprises sodium carbonate and / or sodium hydroxide.

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

[0068] The second mixed salt solution, the solution of the precipitant and the solution of the complexing agent are simultaneously 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 temperature is increased for a second time, and the second mixed salt solution and the precipitant are continuously added, the pH value is maintained in the preset pH range, and the co-precipitation reaction is continued to prepare nickel cobalt manganese hydroxide.

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

[0070] Preferably, the temperature of the preliminary coprecipitation reaction is 50-70°C and does not include 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, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0071] Preferably, the time for simultaneously adding the second mixed salt solution, the solution of the precipitant and the solution of the complexing agent is 2 to 4 hours, for example, it can be 2 hours, 2.3 hours, 2.5 hours, 2.7 hours, 2.9 hours, 3.2 hours, 3.4 hours, 3.6 hours, 3.8 hours or 4 hours, but is not limited to the listed values, and other values ​​not listed within this range are also applicable.

[0072] Preferably, the final temperature of the second heating 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, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0073] Preferably, the second heating rate is 2 to 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, but is not limited to the listed values, and other values ​​not listed in this range are also applicable.

[0074] Preferably, the duration of continuing to maintain the coprecipitation reaction is 1 to 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, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0075] Preferably, in the step S3, the flow rate ratio of 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 raw material ratio is controlled by the flow rates of the three. The number of portions of the second mixed salt solution is 2.6, 2.7, 2.8, 2.9 or 3.0, etc.; the number of portions 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 step S3, the precipitant comprises sodium carbonate and / or sodium hydroxide.

[0077] Preferably, in the step S3, the concentration of the precipitant in the precipitant solution is 4 to 10 mol / L, for example, 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 to EDTA in the complexing agent is 0.4 to 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 invention, 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 ternary precursor ratio provided by the present invention has the following mechanism:

[0082] 1) A method of first performing pre-precipitation to prepare a pre-precipitation liquid and then performing a co-precipitation reaction is adopted. This is because the liquid after removing iron, aluminum and chromium contains impurity elements, and these impurity elements are easily entrained or synchronously precipitated during the MHP co-precipitation reaction, thereby reducing the purity of the ternary precursor; by first performing pre-precipitation, a ternary precursor crystal nucleus is formed first, so that in the subsequent co-precipitation reaction, it is more conducive to the co-precipitation of nickel, cobalt and manganese, avoiding the complexation of nickel, cobalt and manganese by EDTA and dimethylamine phosphate, which can not only avoid the precipitation of impurity elements, but also effectively control the element ratio of the ternary precursor.

[0083] 2) The present invention further preferably adds EDTA in the pre-precipitation step. As mentioned above, the pre-precipitation step is to prepare the ternary precursor crystal nucleus. In order to avoid impurities in the crystal nucleus, a trace amount of EDTA is first added during the pre-precipitation process, and the pH is controlled to be high. Under this pH condition, the trace amount of EDTA preferentially complexes with Ca and Mg in the system, which is beneficial to ensure the purity of the final ternary precursor.

[0084] 3) In the coprecipitation reaction process, EDTA and dimethylamine phosphate are introduced as complexing agents. On the one hand, from the perspective of 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 are relatively close and have a large difference from the LgK of magnesium. Since the impurities contained in the system during the coprecipitation reaction are mainly magnesium, the stability difference between the complexing agent and nickel, cobalt, manganese and magnesium can be used to achieve 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 value range that is suitable for it. It has been verified by experiments that the suitable pH range for EDTA complexing magnesium ions is 9-11, and the present invention controls the pH of the coprecipitation reaction to be 7.5-8.0, so that the pH conditions are more suitable for nickel, cobalt and manganese complexation but not for magnesium complexation, thereby further promoting The present invention improves the stability of nickel-cobalt-manganese complex; at the same time, dimethylamine phosphate is added synchronously, and dimethylamine phosphate can achieve good complexation with Mg and Ca elements in the pH range of 7.0 to 8.0, and its complexation ability with nickel-cobalt-manganese is relatively weak. In the coprecipitation reaction process, dimethylamine phosphate is complexed with impurity elements such as Mg and Ca to avoid the impurity elements being entrained in the ternary precursor precipitation, thereby significantly improving the purity of the ternary precursor; that is, the present invention adopts two different complexing agents to respectively complex with nickel-cobalt-manganese and impurity elements, and the temperature has a significant effect on the complexing activity of EDTA. During the addition of the complexing agent, a suitable complexing temperature condition is maintained so that the complexing agent can be well complexed with nickel-cobalt-manganese, and the temperature of the coprecipitation reaction is increased to exceed the optimal temperature condition for the complexation of EDTA and nickel-cobalt-manganese ions, thereby inhibiting the degree of complexation, thereby inhibiting the crystallization water of the complex, so that the water content of the nickel-cobalt-manganese hydroxide product finally obtained will not be too high.

[0085] 4) Since EDTA has different complexing abilities with elements under different pH conditions, first in the pre-precipitation solution EDTA mainly complexes with trace impurity elements to suppress impurities in the ternary precursor crystal nucleus. When entering the co-precipitation reaction, as the pH conditions change, EDTA is released from the impurity elements, and since the precipitation solubility product and pH conditions of the impurity elements are not met, the impurity elements are released into the solution to complex with dimethylamine phosphate, while EDTA is converted to complex with nickel, cobalt and manganese, thereby achieving the separation of impurity elements and nickel, cobalt and manganese in the co-precipitation reaction, and obtaining a high-purity ternary precursor with low water content.

[0086] The present invention is further described in detail by specific examples. To avoid redundant description, the laterite nickel ore liquid after iron and aluminum removal used in the examples and comparative examples is described as follows:

[0087] The laterite nickel ore iron and aluminum removal liquid used in the present invention is the liquid phase obtained after the laterite nickel ore is subjected to high-pressure acid leaching - first stage iron and aluminum removal - second stage iron and aluminum removal, wherein the main components are shown in Table 1 below, measured 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] This embodiment provides a MHP co-precipitation method based on a ternary precursor ratio, see Figure 1 , the MHP co-precipitation method comprises the following steps:

[0092] (1) Based on the molar ratio of 5:2:3 of the nickel, cobalt and manganese substances in the ternary precursor to be prepared, the ratio of nickel, cobalt and manganese contained in the solution after the iron, aluminum and chromium are removed is adjusted (nickel salt, cobalt salt or manganese salt is additionally added), and after concentration, the solution is divided into a first mixed salt solution and a second mixed salt solution in a ratio of 1:20, wherein the concentration of the sum of the nickel, cobalt and manganese elements in the first mixed salt solution is 0.8 mol / L, and the concentration of the sum of the nickel, cobalt and manganese elements in the second mixed salt solution is 0.8 mol / L.

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

[0094] (3) A solution of a complexing agent containing 0.02 mol / L LEDTA and 0.01 mol / L dimethylamine phosphate (the solvent is water) is taken, and the second mixed salt solution, the sodium hydroxide solution with a concentration of 5 mol / L and the complexing agent solution are simultaneously added to the pre-precipitation solution at a flow rate ratio of 2.6:1:0.3, and a preliminary coprecipitation reaction is carried out at a pH value of 7.5 and a temperature of 50° C. for 4 hours; then the temperature is rapidly raised to 90° C. at a rate of 5° C. / min, and the second mixed salt solution and the sodium hydroxide solution are continuously added at the same rate, the pH value is maintained at 7.5, and the coprecipitation reaction is continued for 1 hour. The obtained coprecipitation reaction material is filtered to obtain a nickel-cobalt-manganese hydroxide finished product.

[0095] Example 2

[0096] This embodiment provides a MHP co-precipitation method based on a ternary precursor ratio, and the MHP co-precipitation method comprises the following steps:

[0097] (1) Based on the molar ratio of 6:2:2 of the nickel, cobalt and manganese substances in the ternary precursor to be prepared, the ratio of nickel, cobalt and manganese contained in the solution after the iron, aluminum and chromium are removed is adjusted (nickel salt, cobalt salt or manganese salt is additionally added), and after concentration, the solution is divided into a first mixed salt solution and a second mixed salt solution in a ratio of 1:15, wherein the concentration of the sum of the nickel, cobalt and manganese elements in the first mixed salt solution is 0.7 mol / L, and the concentration of the sum of the nickel, cobalt and manganese elements in the second mixed salt solution is 0.7 mol / L.

[0098] (2) adding water, 3 mol / L ammonia water, and 4 mol / L sodium hydroxide solution into a reactor to obtain a mixed solution, adjusting the pH to 10 and first heating to 70° C., then adding EDTA and the first mixed salt solution into the reactor for pre-reaction, wherein the concentration of EDTA in the pre-reaction system is 0.04 mol / L, and performing a pre-precipitation reaction at a pH of 10 and a temperature of 70° C. for 50 min to obtain a pre-precipitation solution.

[0099] (3) A solution of a complexing agent containing 0.01 mol / L LEDTA and 0.004 mol / L dimethylamine phosphate (the solvent is water) is taken, and the second mixed salt solution, the sodium hydroxide solution with a concentration of 4 mol / L and the complexing agent solution are simultaneously added to the pre-precipitation solution at a flow rate ratio of 2.8:1:0.4, and a preliminary coprecipitation reaction is carried out at a pH value of 8.0 and a temperature of 60° C. for 2 hours; then the temperature is raised to 70° C. at a rate of 2° C. / min, and the second mixed salt solution and the sodium hydroxide solution are continuously added at the same rate, the pH value is maintained at 8.0, and the coprecipitation reaction is continued for 1.5 hours. The obtained coprecipitation reaction material is filtered to obtain a nickel-cobalt-manganese hydroxide finished product.

[0100] Example 3

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

[0102] (1) Based on the molar ratio of 8:1:1 of the nickel, cobalt and manganese substances in the ternary precursor to be prepared, the ratio of nickel, cobalt and manganese contained in the solution after the iron, aluminum and chromium are removed is adjusted (nickel salt, cobalt salt or manganese salt is additionally added), and after concentration, the solution is divided into a first mixed salt solution and a second mixed salt solution in a ratio of 1:12. The concentration of the sum of the nickel, cobalt and manganese elements in the first mixed salt solution is 0.8 mol / L, and the concentration of the sum of the nickel, cobalt and manganese elements in the second mixed salt solution is 0.8 mol / L.

[0103] (2) Water, 7 mol / L ammonia water, and 5 mol / L sodium hydroxide solution are added to a reactor to obtain a mixed solution, the pH is adjusted to 10.5 and the temperature is first raised to 70° C., and then EDTA and the first mixed salt solution are added to the reactor for pre-reaction. The concentration of EDTA in the pre-reaction system is 0.05 mol / L. The sodium hydroxide solution and ammonia water are pre-precipitated at a pH of 10.5 and a temperature of 70° C. for 1 hour to obtain a pre-precipitated solution.

[0104] (3) A solution of a complexing agent containing 0.05 mol / L LEDTA and 0.025 mol / L dimethylamine phosphate (the solvent is water) is taken, and the second mixed salt solution, the sodium hydroxide solution with a concentration of 5.5 mol / L and the complexing agent solution are simultaneously added to the pre-precipitation solution at a flow rate ratio of 2.9:1:0.3, and a preliminary coprecipitation reaction is carried out at a pH value of 8.0 and a temperature of 60° C. for 4 hours; then the temperature is rapidly raised to 90° C. at a rate of 3° C. / min, and the second mixed salt solution and the sodium hydroxide solution are continuously added at the same rate, the pH value is maintained at 8.0, and the coprecipitation reaction is continued for 2 hours. The obtained coprecipitation reaction material is filtered to obtain a nickel-cobalt-manganese hydroxide finished product.

[0105] Example 4

[0106] This 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 molar ratio of 9:0.5:0.5 of the nickel, cobalt and manganese substances in the ternary precursor to be prepared, the ratio of nickel, cobalt and manganese contained in the solution after the iron, aluminum and chromium are removed is adjusted (nickel salt, cobalt salt or manganese salt is additionally added), and after concentration, the solution is divided into a first mixed salt solution and a second mixed salt solution in a ratio of 1:9, wherein the concentration of the sum of the nickel, cobalt and manganese elements in the first mixed salt solution is 1.1 mol / L, and the concentration of the sum of the nickel, cobalt and manganese elements in the second mixed salt solution is 1.1 mol / L.

[0108] (2) Water, 8 mol / L ammonia water, and 10 mol / L sodium hydroxide solution are added to a reactor to obtain a mixed solution, the pH is adjusted to 11, and the temperature is first raised to 80° C. EDTA and the first mixed salt solution are then added to the reactor for a pre-reaction. The concentration of EDTA in the pre-reaction system is 0.01 mol / L. A pre-precipitation reaction is performed at a pH of 11 and a temperature of 80° C. for 1.5 hours to obtain a pre-precipitation solution.

[0109] (3) A solution of a complexing agent having a concentration of 0.1 mol / L LEDTA and 0.06 mol / L dimethylamine phosphate (the solvent is water) is taken, and a second mixed salt solution, a sodium hydroxide solution having a concentration of 10 mol / L and a solution of the complexing agent are simultaneously added to the pre-precipitation solution at a flow rate ratio of 3.0:1:0.5, and a preliminary coprecipitation reaction is carried out at a pH value of 8.5 and a temperature of 70°C for 3 hours; then the temperature is rapidly raised to 80°C at a rate of 2.5°C / min, and the second mixed salt solution and the sodium hydroxide solution are continuously added at the same rate, the pH value is maintained at 8.5, and the coprecipitation reaction is continued for 2 hours. The obtained coprecipitation reaction material is filtered to obtain a nickel-cobalt-manganese hydroxide finished product.

[0110] Example 5

[0111] This embodiment provides a MHP co-precipitation method based on a ternary precursor ratio. The MHP co-precipitation method is the same as that of Embodiment 1 except that EDTA is not added in step (2), and will not be described in detail here.

[0112] Example 6

[0113] This embodiment provides a MHP co-precipitation method based on a ternary precursor ratio. The MHP co-precipitation method is the same as that of Embodiment 1 except that 0.02 mol / L dimethylamine phosphate is added in step (3), and will not be described again.

[0114] Example 7

[0115] This embodiment provides a MHP co-precipitation method based on a ternary precursor ratio. The MHP co-precipitation method is the same as that of Embodiment 1 except that 0.005 mol / L dimethylamine phosphate is added in step (3), and will not be described again.

[0116] Example 8

[0117] This embodiment provides a MHP co-precipitation method based on a ternary precursor ratio. The MHP co-precipitation method is the same as that of Embodiment 1 except that the co-precipitation reaction temperature is maintained at 50° C. in step (3), and will not be described in detail herein.

[0118] Example 9

[0119] This embodiment provides a MHP co-precipitation method based on a ternary precursor ratio. The MHP co-precipitation method is the same as that of Embodiment 1 except that the temperature of the preliminary co-precipitation reaction in step (3) is 90° C., and will not be described in detail here.

[0120] Example 10

[0121] This embodiment provides a MHP co-precipitation method based on a ternary precursor ratio. The MHP co-precipitation method is the same as that of Example 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, and will not be described again.

[0122] Comparative Example 1

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

[0124] Comparative Example 2

[0125] This comparative example provides a MHP co-precipitation method based on a ternary precursor ratio. The MHP co-precipitation method is the same as Example 1 except that EDTA is not added in step (3), and will not be described in detail here.

[0126] Comparative Example 3

[0127] This comparative example provides a MHP co-precipitation method based on a ternary precursor ratio. The MHP co-precipitation method is the same as Example 1 except that dimethylamine phosphate is not added in step (3), and will not be described in detail here.

[0128] Comparative Example 4

[0129] This comparative example provides a MHP co-precipitation method based on a ternary precursor ratio. The MHP co-precipitation method is the same as Example 1 except that dimethylamine phosphate is replaced by citric acid in step (3), and the details are not repeated here.

[0130] The molar ratio of nickel, cobalt and manganese, the purity of nickel, cobalt and manganese hydroxide, the mass fraction of magnesium and the water content of the nickel, cobalt and manganese hydroxide products prepared in Examples 1 to 10 and Comparative Examples 1 to 4 were tested, as shown in Table 2.

[0131] Table 2

[0132]

[0133]

[0134] From Table 2 we can see that:

[0135] It can be seen from Examples 1 to 4 that the amount ratio of the prepared nickel-cobalt-manganese hydroxide product to the nickel-cobalt-manganese substance of the initial ternary precursor to be prepared is very close, which proves that the MHP co-precipitation method based on the ternary precursor ratio described in the present invention can well achieve nickel-cobalt-manganese co-precipitation; at the same time, the magnesium impurity content is low, the water content can also be controlled at a level below 60%, the total precipitation rate of nickel-cobalt-manganese is above 99%, and the purity of nickel-cobalt-manganese hydroxide is above 99.4wt%, of which the Mg content is less than 0.1wt%.

[0136] By comparing the test examples 1 and 5 and comparative example 2, it can be seen that the addition of EDTA in both step (2) and step (3) is more conducive to improving the precipitation rate of nickel, cobalt and manganese. At the same time, the ratio of the amount of nickel, cobalt and manganese substances is closer to the expected value, and the content of impurities such as Mg in the final product is lower.

[0137] By comparing the test results of Example 1 and Examples 6 to 7, it can be seen that the present invention 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 in the nickel-cobalt-manganese hydroxide and ensuring the precipitation rate of nickel-cobalt-manganese.

[0138] By comparing Example 1 with Example 8, it can be seen that Example 8 does not set the temperature to rise after adding the complexing agent, which makes it difficult to inhibit the complexing process of EDTA in the latter stage of the reaction, and the water content of the nickel cobalt manganese hydroxide product obtained is significantly increased.

[0139] Comparative testing of the nickel-cobalt-manganese hydroxide products prepared in Example 1 and Example 9 shows that the total precipitation rate in Example 9 is significantly lower than that in Example 1, indicating that the reaction temperature in Example 9 is higher than that in Example 1 during the preliminary coprecipitation reaction, so that the temperature condition exceeds the suitable complexing range of EDTA for nickel-cobalt-manganese, which reduces the complexing degree of EDTA for nickel-cobalt-manganese, thereby reducing the precipitation rate of nickel-cobalt-manganese.

[0140] By comparing Example 1 with Example 10, it can be seen that in Example 10, the pH is adjusted higher during the complexation reaction relative to Example 1, so that the degree of complexation of EDTA to nickel, cobalt and manganese is reduced, while the degree of complexation with magnesium is increased, thereby causing the molar ratio of nickel, cobalt and manganese to fluctuate, and the magnesium impurity content is significantly increased.

[0141] By comparing the nickel-cobalt-manganese hydroxide products prepared in Example 1 and Comparative Example 1, the total precipitation rate of Comparative Example 1 decreased to 78.5% relative to that of Example 1, proving that if the pre-precipitation solution is not introduced during the complex reaction, the precipitation rate of nickel-cobalt-manganese will be reduced.

[0142] By comparing Example 1 with Comparative Examples 3 to 4, it can be seen that the present invention selects dimethylamine phosphate and EDTA for compound 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 present invention illustrates the detailed features of the present invention through the above embodiments, but the present invention is not limited to the above detailed features, that is, it does not mean that the present invention must rely on the above detailed features to be implemented. Those skilled in the art should understand that any improvement to the present invention, equivalent replacement of the technical features selected by the present invention, addition of auxiliary technical features, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A MHP co-precipitation method based on a ternary precursor ratio, characterized in that: The following steps are involved: 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 solution after iron, aluminum and chromium are removed, and the obtained concentrated solution is distributed into a first mixed salt solution and a second mixed salt solution; S2, mixing water, ammonia water, a precipitant and the first mixed salt solution uniformly to obtain a pre-precipitation solution; S3, adding the second mixed salt solution, the precipitant and the complexing agent to the pre-precipitation solution simultaneously to carry out a precipitation reaction to prepare nickel-cobalt-manganese hydroxide; The complexing agent includes dimethylamine phosphate and EDTA.

2. The MHP co-precipitation method based on a 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; Preferably, the liquid after iron, aluminum and chromium removal is a liquid phase obtained after laterite nickel ore is subjected to high pressure acid leaching, first stage iron and aluminum removal, and second stage iron and aluminum removal in sequence; Preferably, the liquid after iron removal and aluminum chromium removal contains nickel, cobalt and manganese elements, and the liquid after iron removal and aluminum chromium removal contains impurity elements; Preferably, the impurity elements include any one of magnesium, aluminum, iron, chromium or calcium, or a combination of at least two of them.

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

4. The MHP co-precipitation method based on a ternary precursor ratio according to claim 3, characterized in that: In the step S1, the volume ratio of the first mixed salt solution to the second mixed salt solution is 1:(9-20).

5. The MHP co-precipitation method based on a ternary precursor ratio according to claim 4, characterized in that: In the step S2, the specific steps of the step S2 are as follows: Adding water, ammonia water and a precipitant into a reactor to obtain a mixed solution, adjusting the pH and first heating the solution, and then adding the first mixed salt solution into the reactor for pre-reaction to obtain the pre-precipitation solution; Preferably, the concentration of the precipitant in the mixed solution is 4 to 10 mol / L; Preferably, the concentration of aqueous ammonia in the mixed solution is 3 to 8 mol / L; Preferably, the pH is adjusted to 9-11; Preferably, the final temperature of the first heating is 60-80°C; Preferably, the pre-reaction time is 1 to 2 hours; Preferably, the pre-reaction is carried out under the final temperature condition of the first heating; Preferably, EDTA is also added in the pre-reaction; Preferably, the concentration of EDTA added in the pre-reaction is 0.01-0.05 mol / L.

6. The MHP co-precipitation method based on a ternary precursor ratio according to claim 4, characterized in that: In the step S2, the precipitating agent includes sodium carbonate and / or sodium hydroxide.

7. The MHP co-precipitation method based on a ternary precursor ratio according to claim 1, characterized in that: The specific steps of the S3 step are as follows: The second mixed salt solution, the solution of the precipitant and the solution of the complexing agent are simultaneously added to the pre-precipitation solution at a preset flow rate to perform a preliminary co-precipitation reaction, and the pH value is maintained within a preset pH range during the preliminary co-precipitation reaction; Then, the temperature is raised for a second time, and the second mixed salt solution and the precipitant are continuously added, the pH value is maintained within a preset pH range, and the coprecipitation reaction is continued to prepare nickel-cobalt-manganese hydroxide; Preferably, the preset pH range is 7.5 to 8.0; Preferably, the temperature of the preliminary coprecipitation reaction is 50 to 70° C. and does not include 70° C.; Preferably, the second mixed salt solution, the precipitant solution and the complexing agent solution are added simultaneously for 2 to 4 hours; Preferably, the final temperature of the second heating is 70-90°C; Preferably, the second heating rate is 2-5°C / min; Preferably, the coprecipitation reaction is continued for 1 to 2 hours.

8. The MHP co-precipitation method based on a ternary precursor ratio according to claim 7, characterized in that: In the step S3, 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).

9. The MHP co-precipitation method based on a ternary precursor ratio according to claim 7, characterized in that: In the step S3, the precipitating agent includes sodium carbonate and / or sodium hydroxide.

10. The MHP co-precipitation method based on a ternary precursor ratio according to claim 7, characterized in that: The complexing agent concentration in the complexing agent solution is 0.01-0.2 mol / L; Preferably, the molar ratio of dimethylamine phosphate to EDTA in the complexing agent is 0.4-0.6:1.

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