Preparation method of nickel-cobalt-manganese raw material with ion common balance in laterite-nickel ore hydrometallurgy

Abstract

The invention discloses a preparation method of a nickel-cobalt-manganese raw material with ion joint balance in laterite-nickel ore hydrometallurgy. The preparation method comprises the following steps: acquiring initial feed liquid parameters, actual pH of feed liquid at a reaction endpoint and a target precipitation rate of target metal; constructing a first theoretical relationship model of the theoretical pH of the reaction endpoint feed liquid and the target precipitation rate of the target metal, and obtaining the theoretical pH of the reaction endpoint feed liquid based on the initial feed liquid parameters and the first theoretical relationship model; and judging whether the reaction is stopped or not based on the theoretical pH of the reaction endpoint feed liquid and the actual pH of the reaction endpoint feed liquid. According to the invention, from the perspective of ion balance, the MHP sinking process is guided. By means of the method, the theoretical pH of the reaction endpoint feed liquid can be directly obtained on the basis of the initial feed liquid parameters and the target precipitation rate of the target metal, so that whether the reaction is stopped or not is judged according to the theoretical pH of the reaction endpoint feed liquid and the actual pH of the reaction endpoint feed liquid.

Description

Technical Field

[0001] The present application relates to the technical field of hydrometallurgy, and in particular to a method for preparing a nickel-cobalt-manganese raw material with ion co-balance in laterite nickel ore hydrometallurgy. Background Art

[0002] In the context of the new energy era, laterite nickel ore is a key nickel resource that has attracted widespread attention. Compared with pyrometallurgical technology, laterite nickel ore hydrometallurgical technology has obvious advantages in energy consumption, raw material adaptability, cost and environmental protection. In the field of hydrometallurgy, the design of the full-process hydrometallurgical process is closely related to the balance relationship of various ions. The full-process hydrometallurgical process based on laterite nickel ore involves high-pressure leaching, cyclic leaching and neutralization, iron and aluminum removal, and MHP (nickel cobalt hydroxide) precipitation. How to design, evaluate and optimize the process conditions of each process section depends on the balance relationship of various ions in the aqueous solution.

[0003] At present, the quality of MHP products prepared by the hydrometallurgical process of laterite nickel ore varies. As a process segment for the output of products in the full-process hydrometallurgical process of laterite nickel ore, the precipitation of MHP has a crucial impact on the product. In the process of precipitation of MHP from laterite nickel ore, the type of precipitant, the amount of precipitant added, the degree of reaction, etc. have a decisive influence on the quality of MHP. In actual industrial production, the amount of precipitant added and the degree of reaction are generally evaluated manually through experience. However, if the composition of the nickel-cobalt solution changes, it is impossible to accurately judge the amount of precipitant added and the degree of reaction, which ultimately affects the quality of the MHP product. Summary of the invention

[0004] The purpose of this application is to overcome the above-mentioned technical deficiencies, propose a method for preparing nickel-cobalt-manganese raw materials with ion co-balance in laterite nickel ore hydrometallurgy, and solve the technical problem in the prior art that the reaction degree is generally artificially evaluated through experience, resulting in uneven quality of MHP products.

[0005] The present application provides a method for preparing a nickel-cobalt-manganese raw material with ion co-balance in laterite nickel ore hydrometallurgy, comprising the following steps: Obtaining initial feed solution parameters, actual pH of the reaction end point feed solution, and target precipitation rate of the target metal; Constructing a first theoretical relationship model between the theoretical pH of the reaction end point feed solution and the target precipitation rate of the target metal, and obtaining the theoretical pH of the reaction end point feed solution based on the initial feed solution parameters and the first theoretical relationship model; Whether to stop the reaction is determined based on the theoretical pH of the reaction end point feed solution and the actual pH of the reaction end point feed solution.

[0006] Compared with the prior art, the beneficial effects of this application include: The present application establishes the first theoretical relationship model between the theoretical pH of the reaction end point feed solution and the target precipitation rate of the target metal from the perspective of ion balance, and guides the precipitation MHP process. Through the method of the present application, the theoretical pH of the reaction end point feed solution can be directly obtained based on the initial feed solution parameters and the target precipitation rate of the target metal, so as to determine whether to stop the reaction through the theoretical pH of the reaction end point feed solution and the actual pH of the reaction end point feed solution; at the same time, the test method of the actual pH of the reaction end point feed solution is simpler and more intuitive than the test method of the metal concentration in the reaction end point feed solution, and it is easier to directly determine the degree of reaction through pH, ​​so as to regulate the reaction process. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 It is a process flow chart of an embodiment of a method for preparing a nickel-cobalt-manganese raw material with ion co-balance in laterite nickel ore hydrometallurgy provided by the present application; Figure 2 It is a relationship diagram between the target precipitation rates of nickel, cobalt, manganese and magnesium and the theoretical pH of the reaction endpoint solution established based on the first theoretical relationship model in Example 1 of the present application. DETAILED DESCRIPTION

[0008] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0009] See also Figure 1 The present application provides a method for preparing a nickel-cobalt-manganese raw material with ion co-balance in laterite nickel ore hydrometallurgy, comprising the following steps: S1. Obtaining initial feed solution parameters, actual pH of the reaction end point feed solution, and target precipitation rate of the target metal; wherein the initial feed solution parameters include the composition and volume of the initial feed solution; S2, constructing a first theoretical relationship model between the theoretical pH of the reaction end point feed solution and the target precipitation rate of the target metal, and obtaining the theoretical pH of the reaction end point feed solution based on the initial feed solution parameters and the first theoretical relationship model; S3. Determine whether to stop the reaction based on the theoretical pH of the reaction end point feed solution and the actual pH of the reaction end point feed solution.

[0010] The present application establishes the first theoretical relationship model between the theoretical pH of the reaction end point feed solution and the target precipitation rate of the target metal from the perspective of ion balance, and guides the precipitation MHP process. Through the method of the present application, the theoretical pH of the reaction end point feed solution can be directly obtained based on the initial feed solution parameters and the target precipitation rate of the target metal, so as to determine whether to stop the reaction through the theoretical pH of the reaction end point feed solution and the actual pH of the reaction end point feed solution; at the same time, the test method of the actual pH of the reaction end point feed solution is simpler and more intuitive than the test method of the metal concentration in the reaction end point feed solution, and it is easier to directly determine the degree of reaction through pH, ​​so as to regulate the reaction process.

[0011] The present application does not limit the source of the initial feed liquid, and those skilled in the art can select it according to actual conditions. In some specific embodiments of the present application, the initial feed liquid is a laterite nickel ore after iron and aluminum are removed, which is reacted with a precipitant to prepare MHP slurry.

[0012] Since the key target metal element for hydrometallurgical recovery of laterite nickel ore is nickel, and the precipitation rates of cobalt and manganese and the composition of MHP are basically determined after the precipitation rate of nickel is determined, in some specific embodiments of the present application, the target metal is nickel.

[0013] The present application does not limit the type of precipitant, and those skilled in the art can select according to actual conditions. In some specific embodiments of the present application, the precipitant can be sodium hydroxide solution and / or magnesium oxide slurry, etc.

[0014] In this embodiment, the actual pH of the reaction end point feed solution is obtained by detecting the filtrate obtained by solid-liquid separation of the slurry after the initial feed solution reacts with the precipitant. The present application does not limit the method of solid-liquid separation, and those skilled in the art can choose according to actual conditions. For example, solid-liquid separation can be performed by filtration.

[0015] In some specific embodiments of the present application, the reaction end point feed solution is obtained as follows: The initial feed liquid is mixed with a precipitant to react to obtain an MHP slurry; The MHP slurry is thickened to obtain an MHP thick underflow; The MHP dense underflow is filtered to obtain an MHP filter cake and a filtrate, and the obtained filtrate is the reaction end point feed liquid.

[0016] Furthermore, the MHP filter cake is washed with water to obtain wash water, and the filtrate and wash water are sampled and tested to calculate the actual precipitation rate.

[0017] In this implementation, in step S2, the calculation formula corresponding to the first theoretical relationship model is as follows: 0% (1) In the formula, K sp is the solubility product constant, K w is the ionic product of water, C i is the mass concentration of the target metal in the initial feed solution, A is the relative atomic mass of the target metal, R is the target precipitation rate of the target metal, pH is the theoretical pH of the feed solution at the reaction endpoint, and X is the chemical valence state of the target metal.

[0018] Specifically, in step S2, the step of constructing a first theoretical relationship model between the theoretical pH of the reaction end point feed solution and the target precipitation rate of the target metal includes: S21. Construct the solubility product constant model and the water ion product constant model; Among them, the solubility product constant model is constructed based on the hydrolysis equilibrium reaction equation of the target metal, and the hydrolysis equilibrium reaction equation of the target metal is:

[0019] Where X is the chemical valence state of the target metal.

[0020] Among them, the solubility product constant (K sp ), referred to as solubility product, represents the product of the concentration powers of each ion when the precipitate reaches the precipitation-dissolution equilibrium state in the solution. The concentration of the target metal in the reaction end solution and the solubility product constant (K) when it reaches the precipitation-dissolution equilibrium sp ) satisfies the following solubility product constant model: (2) Where A is the relative atomic mass of the target metal, C f is the mass concentration of the target metal in the reaction end solution, C f (OH - ) is the OH in the liquid at the end of the reaction - Molar concentration of ions, K sp It is only related to temperature or pressure. At normal pressure and temperature of 25°C, the K of Ni(OH)2 is sp Take 5.92×10 -16 、K of Co(OH)2 sp Take 1.6×10 -15 、K of Mn(OH)2 sp Take 4×10 -14 , K of Mg(OH)2 sp Take 5.61×10 -12 .

[0021] Among them, the ion product constant of water, referred to as the ion product of water, indicates that when the ionization of water reaches equilibrium, the ionization product H + Concentration and OH - The product of the concentrations, OH in the reaction end solution -The ion concentration and the theoretical pH of the reaction end point solution satisfy the following water ion product constant model: (3) In the formula, the ion product of water K w It is only related to temperature or pressure. At normal pressure and temperature of 25°C, K w Take 1×10 -14 , pH is the theoretical pH of the reaction end point solution.

[0022] S22, constructing a theoretical relationship model between the precipitation rate of the target metal and the initial feed liquid parameters and the reaction end point feed liquid parameters; Among them, the formula corresponding to the theoretical relationship model between the precipitation rate of the target metal and the initial liquid parameters and the reaction end liquid parameters is: (4) Where R is the target precipitation rate of the target metal; C i and C f are the mass concentrations of the metal before and after the metal hydrolysis reaction (i.e., the mass concentration of the target metal in the initial feed solution and the mass concentration of the target metal in the feed solution at the reaction end point); V i and V f are the volumes of the solutions before and after the hydrolysis reaction (i.e., the volume of the initial feed solution and the volume of the reaction end solution). Since the volume of the precipitant added during the MHP precipitation process is very small relative to the initial feed solution, it can be considered that V i ≈V f .

[0023] S23. Based on the solubility product constant model, the ion product constant model of water, and the theoretical relationship model between the precipitation rate of the target metal and the initial slurry parameters and the reaction endpoint slurry parameters, a first theoretical relationship model between the theoretical pH of the reaction endpoint slurry and the target precipitation rate of the target metal is constructed.

[0024] Wherein, step S23 specifically includes: combining (2), (3) and (4), that is, a first theoretical relationship model between the theoretical pH of the reaction end point solution and the target precipitation rate of the target metal.

[0025] In this embodiment, before step S2, it also includes: constructing a second theoretical relationship model between the amount of precipitant and the target precipitation rate of the target metal, and obtaining the amount of precipitant based on the initial slurry parameters and the second theoretical relationship model.

[0026] Specifically, the calculation formula corresponding to the second theoretical relationship model is as follows: (5) In the formula, m is the amount of precipitant; C Ni , C Coare the mass concentrations of nickel ions and cobalt ions in the initial solution, respectively; R is the target precipitation rate of the target metal; B is the molecular weight of the precipitant; P is the mass concentration of the precipitant; and η is the precipitant dosage coefficient obtained by fitting the test results.

[0027] More specifically, the precipitant is sodium hydroxide solution, and the precipitant dosage coefficient η is 2.08; or, the precipitant is magnesium oxide slurry, and the precipitant dosage coefficient η is 0.95.

[0028] In the method of the present application, a second theoretical relationship model between the amount of precipitant and the target precipitation rate of the target metal is also established to guide the MHP precipitation process. Through the method of the present application, the amount of precipitant can be directly obtained based on the initial feed liquid parameters and the target precipitation rate of the target metal.

[0029] In this embodiment, in step S3, the step of judging whether to stop the reaction based on the theoretical pH of the reaction endpoint feed solution and the actual pH of the reaction endpoint feed solution includes: if the ratio of the actual pH of the reaction endpoint feed solution to the theoretical pH of the reaction endpoint feed solution is 99-101%, the reaction is stopped.

[0030] In the method of the present application, when the ratio of the actual pH of the reaction endpoint feed liquid to the theoretical pH of the reaction endpoint feed liquid is less than 99, that is, the reaction has not reached the target reaction degree, the reaction is continued until the ratio of the actual pH of the reaction endpoint feed liquid to the theoretical pH of the reaction endpoint feed liquid reaches 99-101%, and the reaction is stopped.

[0031] This application takes the currently industrialized precipitant sodium hydroxide solution and magnesium oxide slurry as examples, and from the perspective of ion balance, establishes the first theoretical relationship model between the theoretical pH of the reaction end solution and the target precipitation rate of the target metal, and the second theoretical relationship model between the amount of precipitant used in the MHP precipitation process and the target precipitation rate of the target metal, to guide the MHP precipitation process. Based on the ion balance theory and practical experience, the inventor found that when the precipitant is sodium hydroxide solution, the conditions for the establishment of this theory are: the target precipitation rate of nickel ≤93%, the mass concentration of sodium hydroxide solution is 5-15%, the reaction time is 0.5 h ≤ t≤ 3 h, and the reaction temperature is 55℃≤T≤70℃; when the precipitant is magnesium oxide slurry, the conditions for the establishment of this theory are: the target precipitation rate of nickel ≤98%, the mass concentration of magnesium oxide slurry is 3-15%, the reaction time is 4 h ≤ t ≤ 8 h, and the reaction temperature is 55℃≤T≤70℃. The method proposed in this application is established within the above range. In addition, the current MHP precipitation is generally divided into two stages. In order to ensure the quality of MHP products and reduce the cost of subsequent extraction stages, the first MHP stage is the product grade, in which the nickel precipitation rate is generally ≤85%. At the same time, in actual production, the nickel precipitation rate of the MHP product stage is generally around 80%, so the method of this application is sufficient to guide actual production.

[0032] In the examples and comparative examples of the present application, Example 1 is used to illustrate the relationship between the theoretical pH of the reaction end point feed solution and the target precipitation rate of the target metal, and Examples 2-5 and Comparative Examples 1-3 further verify the above method in combination with the specific MHP precipitation process.

[0033] To avoid redundancy, the compositions of the nickel-cobalt solutions used in the following embodiments and comparative examples of the present invention are shown in Table 1.

[0034] Table 1 Composition of nickel-cobalt solution used to prepare MHP after iron and aluminum removal from laterite nickel ore (g / L)

[0035] Example 1 According to the first theoretical model proposed in the present application, it can be inferred that after the MHP reaction is completed, the theoretical pH of the reaction end point liquid has nothing to do with the type of precipitant, but is only related to the target precipitation rate of the target metal, and the target precipitation rate of the target metal and the theoretical pH of the reaction end point liquid both satisfy the relationship of formula (1).

[0036] Taking nickel as an example, when the target precipitation rate of nickel is 80%, 90% and 95%, the theoretical pH of the reaction end point solution can be calculated by substituting each parameter into formula (1). Further, taking the target precipitation rate of nickel as 80% as an example, the relationship between the target precipitation rate of nickel and the theoretical pH of the reaction end point solution is as follows:

[0037] The final pH is 7.35. In formula (1), K w 1×10 -14 , K sp 5.92×10 -16 .

[0038] Similarly, when the target precipitation rate of nickel is 90% and 95%, the theoretical pH of the reaction end point solution is 7.50 and 7.65, respectively.

[0039] The equilibrium constant K of the hydrolysis precipitation reaction of the valuable metal ions nickel, cobalt, manganese and magnesium in the nickel-cobalt solution sp (K sp 5.92×10 -16 , 1.6×10 -15 , 4×10 -14 , 5.61×10 -12 ) are respectively brought into the first theoretical model proposed in this application, it can be obtained that during the MHP reaction, Figure 2 Shown is a graph showing the relationship between the target precipitation rates of nickel, cobalt, manganese and magnesium and the theoretical pH of the reaction endpoint feed solution.

[0040] See also Figure 2 ,pass Figure 2 It can be seen that the hydrolysis order of nickel, cobalt, manganese and magnesium is nickel>cobalt>manganese>magnesium. When the theoretical pH of the reaction end solution is less than 8, magnesium will basically not be hydrolyzed under the same pH conditions, and manganese has little effect on the hydrolysis of nickel and cobalt. Therefore, the amount of alkali used in the MHP preparation process can be calculated according to the concentration of nickel and cobalt in the nickel-cobalt solution. This is the theoretical basis for the construction of the second theoretical model.

[0041] The hydrometallurgy of laterite nickel ore mainly recovers nickel, followed by cobalt. Therefore, the present application focuses on the actual precipitation rate of nickel and the actual reaction endpoint pH to verify the first theoretical model and the second theoretical model proposed in the present application.

[0042] Example 2 (1) Mix 48% liquid alkali with industrial water to obtain an alkali solution with a mass concentration of 5%; (2) The liquid after iron and aluminum removal from laterite nickel ore is mixed with an alkaline solution for precipitation reaction to obtain MHP slurry. The reaction temperature is 65°C and the reaction time is 2 h. The target precipitation rate of nickel in this process section needs to be controlled to 80%. Substituting the mass concentrations of nickel and cobalt in Table 1 into formula (5), the addition amount m of 48% liquid alkali is:

[0043] That is, the mass of 48% liquid caustic soda added per liter of nickel-cobalt solution is m = 9.16 g. In formula (5), the molecular weight of sodium hydroxide is 40 g / mol, and η is 2.08.

[0044] (3) thickening the MHP slurry to obtain an MHP thick underflow; (4) The dense underflow was filtered to obtain MHP filter cake and filtrate. After the filtrate was sampled and tested, it was found that the actual pH of the reaction end point feed liquid was 7.38, which was basically consistent with the theoretical pH of the reaction end point feed liquid. In addition, the MHP filter cake was washed with industrial water to obtain wash water. After the filtrate and wash water were sampled and tested, the actual precipitation rate of nickel was calculated to be 80.79%, which was also very close to the target precipitation rate of nickel, verifying the rationality of the method of this application.

[0045] (5) Part of the concentrated underflow is returned to the MHP precipitation process as seed crystals.

[0046] Example 3 Different from Example 2, 48% liquid caustic soda is mixed with industrial water to obtain a 10% alkaline solution with a mass fraction for precipitation reaction, and the actual precipitation rate of nickel calculated is 79.16%, and the actual pH of the reaction end point feed liquid is 7.31. Due to the increase in liquid caustic soda concentration, local over-alkalinity can be caused, so the precipitation rate of nickel slightly decreases. However, within the scope of alkaline solution concentration commonly used in production as defined in the present application, the relationship between the amount of sodium hydroxide proposed in the present application and the precipitation rate of nickel is applicable.

[0047] Example 4 The difference from Example 2 is that the target precipitation rate of nickel is 90%.

[0048] It can be calculated that the amount of 48% liquid alkali added is:

[0049] That is: the mass of 48% liquid alkali added to each liter of nickel-cobalt solution is m=10.31 g.

[0050] After the filtrate was sampled and tested, it was found that the actual pH of the reaction end point feed solution was 7.45, and the actual precipitation rate of nickel was calculated to be 88.25%. It can be found that there is a difference of 1.75% between the actual precipitation rate and the target precipitation rate, but it has little effect on the quality of the MHP product. However, as the target precipitation rate of nickel continues to increase, the actual precipitation rate of nickel under the calculated sodium hydroxide dosage conditions will deviate a little more than the target precipitation rate. The experiment found that the relationship between the amount of sodium hydroxide and the precipitation rate of nickel proposed in this application should be used as much as possible when the target precipitation rate of nickel is ≤93%.

[0051] Example 5 The composition of the nickel-cobalt solution is the same as that of Example 2, except that magnesium oxide is used as a precipitant.

[0052] (1) Mixing magnesium oxide with a mass fraction of 93% with industrial water to obtain an alkali slurry with a mass concentration of 5%; (2) The liquid after iron and aluminum removal from laterite nickel ore is mixed with alkaline slurry for precipitation reaction to obtain MHP slurry. The reaction temperature is 65°C and the reaction time is 5 h. If the target precipitation rate of nickel needs to be controlled to 80% in this process section, the mass concentrations of nickel and cobalt in Table 1 are substituted into formula (5) to obtain the addition amount m of 93% magnesium oxide:

[0053] That is, the added mass of 93% magnesium oxide in each liter of nickel-cobalt solution is m = 2.17 g. In formula (5), the molecular weight of magnesium oxide is 40.3 g / mol, and η is 0.95.

[0054] (3) thickening the MHP slurry to obtain an MHP thick underflow; (4) The dense underflow was filtered to obtain MHP filter cake and filtrate. After the filtrate was sampled and tested, it was found that the actual pH of the reaction end point feed liquid was 7.40, which was very close to the theoretical pH of the reaction end point feed liquid. In addition, MHP was washed with industrial water to obtain wash water. After the filtrate and wash water were sampled and tested, it was calculated that the actual precipitation rate of nickel was 80.88%, which was also very close to the target precipitation rate of nickel, indicating that the method of the present application can also be well applied to the system where magnesium oxide is used as the precipitant.

[0055] Example 6 The difference from Example 5 is that the target precipitation rate of nickel is 95%. It can be calculated that the addition amount m of 93% magnesium oxide is:

[0056] That is, the added mass of 93% magnesium oxide in each liter of nickel-cobalt solution is m=2.58 g. The actual precipitation rate of nickel was found to be 95.45%, and the actual pH of the reaction end solution was 7.70.

[0057] Comparative Example 1 The difference from Example 2 is that the MHP precipitation reaction time is 0.2 h, and the other reaction conditions are the same.

[0058] The actual pH of the reaction end point solution was found to be 7.48, and the actual precipitation rate of nickel was calculated to be 83.61%. It can be found that the actual reaction end point pH = 7.48 is quite different from the theoretical end point pH of 7.35 calculated by formula (1). At the same time, although nickel is more easily hydrolyzed than cobalt and manganese, the nickel precipitation rate is higher when the reaction time is 0.2 h, but due to the short reaction time, the MHP slurry has a small particle size and is difficult to filter.

[0059] Comparative Example 2 The difference from Example 2 is that the MHP precipitation reaction time is 4 h, and the other reaction conditions are the same.

[0060] The test found that the actual pH of the reaction end point solution was 7.26 (theoretical reaction end point pH = 7.35), and the actual precipitation rate of nickel was only 75.25%. Therefore, the reaction time should not be too long when sodium hydroxide is used as a precipitant. Too long a reaction time will promote the oxidation and hydrolysis of manganese, thereby causing a decrease in the nickel precipitation rate.

[0061] Comparative Example 3 The difference from Example 5 is that the MHP precipitation reaction time is 1.5 h, and the other reaction conditions are the same.

[0062] The test found that the actual pH of the reaction end point solution was 7.24 (theoretical reaction end point pH = 7.35), and the nickel precipitation rate was only 73.46%. Therefore, when magnesium oxide is used as a precipitant, a short reaction time will result in a low nickel precipitation rate.

[0063] Comparative Example 4 The difference from Example 5 is that the MHP precipitation reaction time is 9 h, and the other reaction conditions are the same.

[0064] The actual pH of the reaction end point solution was 7.43 (theoretical reaction end point pH = 7.35), and the nickel precipitation rate was 82.93%. When magnesium oxide is used as a precipitant, the reaction time is too long, the nickel precipitation rate will increase slightly, but the cobalt precipitation rate will drop to 66.83%. In order to reduce transportation costs, the reaction time should be appropriate.

[0065] The specific implementation methods of the present application described above do not constitute a limitation on the protection scope of the present application. Any other corresponding changes and modifications made according to the technical concept of the present application should be included in the protection scope of the claims of the present application.

Claims

1. A method for preparing a nickel-cobalt-manganese raw material with ion co-balance in laterite nickel ore hydrometallurgy, characterized in that: The following steps are involved: Obtaining initial feed solution parameters, actual pH of the reaction end point feed solution, and target precipitation rate of the target metal; Constructing a first theoretical relationship model between the theoretical pH of the reaction end point feed solution and the target precipitation rate of the target metal, and obtaining the theoretical pH of the reaction end point feed solution based on the initial feed solution parameters and the first theoretical relationship model; Whether to stop the reaction is determined based on the theoretical pH of the reaction endpoint feed solution and the actual pH of the reaction endpoint feed solution.

2. The method for preparing a nickel-cobalt-manganese raw material with ion co-balance in laterite nickel ore hydrometallurgy according to claim 1, characterized in that: The initial feed liquid parameters are obtained by detecting the liquid after iron and aluminum removal from laterite nickel ore; the actual pH of the reaction end point feed liquid is obtained by detecting the filtrate obtained by solid-liquid separation of the slurry after the initial feed liquid reacts with the precipitant.

3. The method for preparing nickel-cobalt-manganese raw materials with ion co-balance in laterite nickel ore hydrometallurgy according to claim 1, characterized in that: The calculation formula corresponding to the first theoretical relationship model is as follows: 0%（1） In the formula, K sp is the solubility product constant, K w is the ionic product of water, C i is the mass concentration of the target metal in the initial feed solution, A is the relative atomic mass of the target metal, R is the target precipitation rate of the target metal, pH is the theoretical pH of the feed solution at the reaction endpoint, and X is the chemical valence state of the target metal.

4. The method for preparing a nickel-cobalt-manganese raw material with ion co-balance in laterite nickel ore hydrometallurgy according to claim 1, characterized in that: The step of constructing a first theoretical relationship model between the theoretical pH of the reaction endpoint feed solution and the target precipitation rate of the target metal comprises: Construct the solubility product constant model and the ion product constant model of water; Constructing a theoretical relationship model between the precipitation rate of the target metal and the initial feed liquid parameters and the reaction end point feed liquid parameters; Based on the solubility product constant model, the ion product constant model of water and the theoretical relationship model between the precipitation rate of the target metal and the initial slurry parameters and the reaction endpoint slurry parameters, a first theoretical relationship model between the theoretical pH of the reaction endpoint slurry and the target precipitation rate of the target metal is constructed.

5. The method for preparing nickel-cobalt-manganese raw materials with ion co-balance in laterite nickel ore hydrometallurgy according to claim 4, characterized in that: The calculation formula corresponding to the solubility product constant model is as follows: （2） Where A is the relative atomic mass of the target metal, C f is the mass concentration of the target metal in the reaction end solution, C f (OH - ) is the OH in the reaction end solution - The molar concentration of the ion; The calculation formula corresponding to the ion product constant model is as follows: （3） Wherein, pH is the theoretical pH of the reaction end point solution; The calculation formula corresponding to the theoretical relationship model between the precipitation rate of the target metal and the initial feed liquid parameters and the reaction end point feed liquid parameters is: （4） Where R is the target precipitation rate of the target metal; C i and C f are the mass concentration of the target metal in the initial solution and the mass concentration of the target metal in the solution at the end of the reaction, respectively; V i and V f are the volume of the initial feed solution and the volume of the reaction end solution, V i ≈V f .

6. The method for preparing nickel-cobalt-manganese raw materials with ion co-balance in laterite nickel ore hydrometallurgy according to claim 1, characterized in that: Before constructing the first theoretical relationship model between the theoretical pH of the reaction end point feed solution and the target precipitation rate of the target metal, the method further includes: A second theoretical relationship model between the amount of precipitant and the target precipitation rate of the target metal is constructed, and the amount of precipitant is obtained based on the initial slurry parameters and the second theoretical relationship model.

7. The method for preparing nickel-cobalt-manganese raw materials with ion co-balance in laterite nickel ore hydrometallurgy according to claim 6, characterized in that: The calculation formula corresponding to the second theoretical relationship model is as follows: （5） Where, m is the amount of precipitant; C Ni , C Co are the mass concentrations of nickel ions and cobalt ions in the initial solution, respectively; R is the target precipitation rate of the target metal; B is the molecular weight of the precipitant; P is the mass concentration of the precipitant; η is the precipitant dosage coefficient obtained by fitting the test results.

8. The method for preparing nickel-cobalt-manganese raw materials with ion co-balance in laterite nickel ore hydrometallurgy according to claim 7, characterized in that: The target metal is nickel, the precipitant is sodium hydroxide solution, and the precipitant dosage coefficient is 2.08; or, the target metal is nickel, the precipitant is magnesium oxide slurry, and the precipitant dosage coefficient is 0.

95.

9. The method for preparing nickel-cobalt-manganese raw materials with ion co-balance in laterite nickel ore hydrometallurgy according to claim 1, characterized in that: The target metal is nickel, the precipitant is sodium hydroxide solution, the target precipitation rate of the target metal is ≤93%, the mass concentration of the sodium hydroxide solution is 5-15%, the reaction time is 0.5 h ≤ t ≤ 3 h, and the reaction temperature is 55°C ≤ T ≤ 70°C; or, The target metal is nickel, the precipitant is magnesium oxide slurry, the target precipitation rate of the target metal is ≤98%, the mass concentration of the magnesium oxide slurry is 3-15%, the reaction time is 4 h ≤ t ≤ 8 h, and the reaction temperature is 55°C ≤T≤70°C.

10. The method for preparing nickel-cobalt-manganese raw materials with ion co-balance in laterite nickel ore hydrometallurgy according to claim 1, characterized in that: The step of judging whether to stop the reaction based on the theoretical pH of the reaction endpoint feed solution and the actual pH of the reaction endpoint feed solution comprises: if the ratio of the actual pH of the reaction endpoint feed solution to the theoretical pH of the reaction endpoint feed solution is 99-101%, the reaction is stopped.

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