Method for removing impurities in the process of recycling valuable metals from retired lithium-ion batteries, impurity remover and its aqueous solution, solution

Abstract

The present invention provides a method for removing impurities during the recovery of valuable metals from retired lithium-ion batteries, an impurity remover, and its aqueous solution and solution. The impurity removal method comprises: (a) leaching the positive electrode material of the retired lithium-ion battery with an acid solution to obtain an acid leaching solution; wherein the acid leaching solution contains lithium ions, nickel ions, cobalt ions, manganese ions, and impurity ions; (b) adjusting the pH value of the acid leaching solution to 4 to 5.5; (c) subsequently adding an impurity remover to the acid leaching solution to adjust the pH value to 5.1 to 7, and then performing an impurity removal reaction to remove the impurity ions; wherein the impurity remover comprises NiCO3 and MOH, and optionally, further comprises at least one of ammonia, M2S, MClO3, and hydrogen peroxide, where M is Na or K. The impurity removal method has a simple process, does not introduce environmentally hazardous reagents such as organic solvents, and has the advantages of high selectivity, high efficiency, and rapidity.

Description

Technical Field

[0001] The present invention relates to the technical field of waste battery treatment, and in particular to a method for removing impurities in the process of recovering valuable metals from retired lithium-ion batteries, an impurity remover, and an aqueous solution and solution thereof. Background Art

[0002] Lithium-ion batteries, with their high energy density, long lifespan, low self-discharge rate, and excellent cycle performance, are widely used in electric vehicles and various portable electronic devices. However, due to their limited service life, a large amount of waste lithium-ion batteries is inevitably generated. The cathode material in waste lithium-ion batteries contains 5-7 wt% lithium, 50-56 wt% nickel, cobalt, and manganese, and 3-10 wt% organic matter. Lithium and cobalt are important strategic metals, often present in higher concentrations than in natural ores. Furthermore, the organic electrolytes and metals in waste lithium-ion batteries are toxic and, if not properly handled, can cause significant environmental pollution. Therefore, recycling waste lithium-ion batteries is essential and urgent to address resource scarcity and protect the environment.

[0003] The hydrometallurgical process has a high recovery rate, high product purity, low energy consumption and less waste gas emissions, and is widely used in the recycling of waste LIBs. In the process of wet recycling of waste LIBs, sulfuric acid is often used to leach the valuable metals in the positive electrode materials of waste lithium batteries to obtain a mixed sulfate solution containing Li, Ni, Co, Mn and other impurity metals such as Cu, Al, Fe, Ca, Mg, etc. Therefore, it becomes a key step to remove the impurity metals Cu, Al, Fe, Ca, Mg, etc. from the mixed sulfate solution and achieve separation from the main metals. For example, Chen et al., from a mixture of waste lithium battery positive electrode materials (LiCoO2, LiMn2O4, LiNi 1 / 3 Mn 1 / 3 Co 1 / 3 O2 and LiFePO4 mixed powder) in the sulfuric acid leaching solution, using sodium hydroxide and Iron and copper are selectively separated. Currently, the recovery of valuable metals from waste lithium batteries is primarily achieved by extracting key elements such as Li, Ni, Co, and Mn to achieve metal separation. However, this process is long and complex, and the commonly used extraction agents are mostly organic, which can be harmful to the environment.

[0004] Based on the above reasons, it is necessary to provide a process with simple process and good impurity removal effect to better remove impurities in the valuable metal recovery process of retired lithium-ion batteries. Summary of the Invention

[0005] The main purpose of the present invention is to provide a method for removing impurities, an impurity remover and its aqueous solution and solution in the process of recovering valuable metals from retired lithium-ion batteries, so as to solve the problems of long process, complicated process or the need to introduce organic matter in the prior art.

[0006] To achieve the above-mentioned object, according to one aspect of the present invention, a method for removing impurities in the process of recovering valuable metals from retired lithium-ion batteries is provided, comprising the following steps: (a) leaching the positive electrode of the retired lithium-ion battery with sulfuric acid to obtain an acid leaching solution; wherein the acid leaching solution contains lithium ions, nickel ions, cobalt ions, manganese ions and impurity ions, and the impurity ions include at least one of copper ions, aluminum ions, iron ions, calcium ions, magnesium ions, lead ions, chromium ions, cadmium ions and zinc ions; (b) adjusting the pH value of the acid leaching solution to 4-5.5; (c) secondly adding an impurity remover thereto to adjust the pH value to 5.1-7, and then performing an impurity removal reaction to remove the impurity ions; wherein the impurity remover comprises NiCO3 and MOH, and optionally, the impurity remover further comprises at least one of ammonia water, M2S, MClO3 and hydrogen peroxide, and M is Na or K.

[0007] Further, the mass ratio of NiCO3 and MOH is 1:(0.8-6), more preferably 1:(1-4); preferably, MOH is NaOH; preferably, M2S is Na2S; preferably, MClO3 is NaClO3; more preferably, the mass of NiCO3 is recorded as m1, the mass of MOH is recorded as m2, the total mass of ammonia water, M2S, MClO3 and hydrogen peroxide is recorded as m3, and m1:m2:m3 is 1:(0.8-6):(0.3-8), preferably 1:(1-4):(0.6-5.5); further preferably, the impurity remover includes NiCO3, NaOH and ammonia water, and the mass ratio between the three is 1:(1-4):(0.6-2); or, the impurity remover includes NiCO3, NaOH, ammonia water, Water and hydrogen peroxide, and the mass ratio among them is 1:(1-4):(0.6-2):(0.3-0.6); or, the impurity remover includes NiCO3, NaOH, ammonia water and Na2S, and the mass ratio among them is 1:(1-4):(0.6-2):(0.5-2); or, the impurity remover includes NiCO3, NaOH, ammonia water and NaClO3, and the mass ratio among them is 1:(1-4):(0.6-2):(0.3-0.7); or, the impurity remover includes NiCO3, NaOH, ammonia water, Na2S, NaClO3 and hydrogen peroxide, and the mass ratio among them is 1:(1-4):(0.6-2):(0.5-2):(0.3-0.7):(0.3-0.6).

[0008] Furthermore, in step (b), after adjusting the pH value of the acid leaching solution to 4-5.5, the solution is filtered first, and then an impurity remover is added to the filtrate in the form of an aqueous solution to carry out an impurity removal reaction; preferably, the mass concentration of the impurity remover in the aqueous solution is 10-30%.

[0009] Furthermore, during the impurity removal reaction, the reaction temperature is 70-90° C., and the reaction time is 1-4 h. Preferably, the impurity removal reaction is carried out under stirring, and the stirring speed is 100-300 rpm / min.

[0010] Furthermore, in the step (b) of adjusting the pH value of the acid leaching solution, sodium hydroxide aqueous solution and / or potassium hydroxide aqueous solution are used as pH regulators; the mass concentrations of the sodium hydroxide aqueous solution and the potassium hydroxide aqueous solution are 5-20%, respectively.

[0011] Furthermore, in the acid leaching solution, the mass concentration of lithium ions is 3-16 g / L, the mass concentration of nickel ions is 13-70 g / L, the mass concentration of cobalt ions is 7-27 g / L, the mass concentration of manganese ions is 30-100 g / L, and the mass concentration of each impurity ion is 0.0001-7 g / L; preferably, in the acid leaching solution, the mass concentration of lithium ions is 7-13 g / L, the mass concentration of nickel ions is 14-20 g / L, the mass concentration of cobalt ions is 14-17 g / L, and the mass concentration of manganese ions is 60-98 g / L. / L, the mass concentration of copper ions is 0.2-0.5 g / L, the mass concentration of aluminum ions is 6-8 g / L, the mass concentration of iron ions is 0.2-1.2 g / L, the mass concentration of calcium ions is 0.05-0.5 g / L, and the mass concentration of magnesium ions is 0.02-1.2 g / L; preferably, step (a) uses sulfuric acid to leach the positive electrode of the retired lithium ion battery, more preferably the mass concentration of sulfuric acid is 10-70%, and the ratio of the mole number of H2SO4 in sulfuric acid to the mole number of metal in the positive electrode is (0.7-2):1.

[0012] Furthermore, after step (c), the method further comprises a filtration step, and the treatment temperature in the filtration step is not lower than 60°C.

[0013] Furthermore, the pH value of the pickling solution after step (b) is lower than the pH value after the impurity remover is added in step (c).

[0014] Furthermore, the difference between the pH value after the impurity remover is added in step (c) and the pH value of the acid leaching solution after step (b) is 0.5-2.

[0015] Furthermore, in step (c), an impurity remover is added to raise the pH value to 5.5 to 6.5.

[0016] According to another aspect of the present invention, there is also provided an impurity remover, which comprises NiCO3 and MOH, and optionally, the impurity remover further comprises at least one of ammonia, M2S, MClO3, and hydrogen peroxide, where M is Na or K; preferably, the mass ratio of NiCO3 and MOH is 1:(0.8-6), more preferably 1:(1-4); preferably, MOH is NaOH; preferably, M2S is Na2S; preferably, MClO3 is NaClO3; more preferably, the mass of NiCO3 is recorded as m1, the mass of MOH is recorded as m2, the total mass of ammonia, M2S, MClO3 and hydrogen peroxide is recorded as m3, and m1:m2:m3 is 1:(0.8-6):(0.3-8), more preferably 1:(1-4):(0.6-5.5); further preferably, the impurity remover comprises NiCO3, NaOH and ammonia, and the mass ratio between the three is is 1:(1-4):(0.6-2); or, the impurity remover includes NiCO3, NaOH, ammonia water and hydrogen peroxide, and the mass ratio among the four is 1:(1-4):(0.6-2):(0.3-0.6); or, the impurity remover includes NiCO3, NaOH, ammonia water and Na2S, and the mass ratio among the four is 1:(1-4):(0.6-2):(0.5-2); or, the impurity remover includes NiCO3, NaOH, ammonia water and NaClO3, and the mass ratio among the four is 1:(1-4):(0.6-2):(0.3-0.7); or, the impurity remover includes NiCO3, NaOH, ammonia water, Na2S, NaClO3 and hydrogen peroxide, and the mass ratio among the six is ​​1:(1-4):(0.6-2):(0.5-2):(0.3-0.7):(0.3-0.6).

[0017] According to another aspect of the present invention, there is also provided an aqueous solution of an impurity remover, characterized in that it contains the above-mentioned impurity remover; preferably, the mass concentration of the impurity remover is 10-30%.

[0018] According to another aspect of the present invention, a solution is provided, which is prepared by the above method; preferably, the solution is used as a precursor raw material; preferably, the solution contains lithium ions at a concentration of 7.5 to 9.5 g / L, nickel ions at a concentration of 14.5 to 17 g / L, cobalt ions at a concentration of 11.5 to 15 g / L, manganese ions at a concentration of 65 to 82 g / L, and impurity ions at a concentration of less than 0.2 g / L, and the impurity ions include at least one of copper ions, aluminum ions, iron ions, calcium ions, magnesium ions, lead ions, chromium ions, cadmium ions, and zinc ions.

[0019] The present invention provides a method for removing impurities during the recovery of valuable metals from retired lithium-ion batteries. Following acid leaching of the positive electrode, an impurity remover is added directly to the acid leaching solution to allow for a reaction. This reaction removes impurities such as copper, aluminum, iron, calcium, and magnesium ions, thereby producing a precursor solution suitable for preparing ternary positive electrode materials. This impurity removal method is simple and does not require the introduction of environmentally hazardous reagents such as organic solvents. Furthermore, the impurity removal process is highly selective, efficient, and rapid. DETAILED DESCRIPTION

[0020] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the embodiments.

[0021] In this document, unless otherwise specified, the numerical units are based on mass.

[0022] Herein, at least three means three, four, five, six, seven, eight or more.

[0023] Valuable metals refer to precious metals and rare metals. For example, the valuable metals in the present invention refer to Li, Ni, Co, Mn, etc.

[0024] As described in the background technology section, in the prior art, the process of recovering valuable metals from retired lithium-ion batteries has a long impurity removal process and complex procedures, or requires the introduction of organic matter and other substances that are harmful to the environment.

[0025] In order to solve the above problems, the present invention provides a method for removing impurities in the process of recovering valuable metals from retired lithium-ion batteries, which comprises the following steps: (a) leaching the positive electrode of the retired lithium-ion battery with an acid solution to obtain an acid leaching solution; wherein the acid leaching solution contains lithium ions, nickel ions, cobalt ions, manganese ions and impurity ions, and the impurity ions include at least one of copper ions, aluminum ions, iron ions, calcium ions, magnesium ions, lead ions, chromium ions, cadmium ions and zinc ions; (b) adjusting the pH value of the acid leaching solution to 4-5.5; (c) subsequently adding an impurity remover thereto to adjust the pH value to 5.1-7, and then performing an impurity removal reaction to remove the impurity ions; wherein the impurity remover comprises NiCO3 and MOH, and optionally, the impurity remover further comprises at least one of ammonia water, M2S, MClO3 and hydrogen peroxide, and M is Na or K.

[0026] Unlike existing impurity removal methods, the present invention adds an impurity remover directly to the acid leaching solution after the positive electrode is acid-leached, allowing the reaction to proceed. This achieves the goal of removing impurity ions such as copper, aluminum, iron, calcium, and magnesium all at once, producing a precursor solution suitable for preparing ternary positive electrode materials. This impurity removal method of the present invention simplifies the process and eliminates the need for environmentally hazardous reagents such as organic solvents. Furthermore, the impurity removal process is highly selective, efficient, and rapid.

[0027] It should be noted that after obtaining the acid leaching solution, the present invention first adjusts the pH value to 4-5.5, for example, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5, 5.1, 5.2, 5.3, 5.4. Then, a specific impurity remover is added to the solution until the pH value reaches 5.1-7, preferably 5.5-6.5 (for example, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 6, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9), and then performs an impurity removal reaction. Because the impurity remover used contains NiCO3 and MOH, nickel carbonate acts as a neutralizing agent, reacting with sulfuric acid to release carbon dioxide, achieving the purpose of neutralization. MOH is used to maintain the pH. The addition of at least one of ammonia, M2S, MClO3, and hydrogen peroxide facilitates superior impurity removal. These impurity removers exhibit a high degree of selective precipitation of impurity ions such as copper, aluminum, iron, calcium, and magnesium ions in the acid leaching solution, particularly at the aforementioned pH values.

[0028] In a preferred embodiment, the pH value of the acid leaching solution after step (b) is less than the pH value after the addition of the impurity remover in step (c). Preferably, the difference between the pH value after the addition of the impurity remover in step (c) and the pH value of the acid leaching solution after step (b) is 0.5-2, for example, 0.6, 0.8, 1.0, 1.2, or 1.5. For example, after step (b), the pH of the acid leaching solution increases from 2-3 before adjustment to 5.1, and further increases to 6.5 after the addition of the impurity remover in step (c). The difference between the pH value after the addition of the impurity remover in step (c) and the pH value of the acid leaching solution after step (b) is 1.4.

[0029] After the above treatment, the present invention can directly obtain a relatively pure precursor solution containing lithium ions, nickel ions, cobalt ions, and manganese ions (up to electronic grade), which can be directly used as a raw material for preparing ternary positive electrode materials.

[0030] In order to further improve the impurity removal effect, in a preferred embodiment, the mass ratio of NiCO3 and MOH is 1: (0.8 to 6), preferably 1: (1 to 4), and more preferably 1: (2 to 3). Controlling the ratio of the two within the above range is more conducive to improving the removal effect of impurity ions such as copper ions, aluminum ions, iron ions, calcium ions and magnesium ions. In order to reduce the introduction of impurity ions while ensuring the impurity removal effect, it is preferred that MOH is NaOH, M2S is Na2S, and MClO3 is NaClO3.

[0031] Taking into account the removal effect of each impurity ion, in a preferred embodiment, the mass of NiCO3 is recorded as m1, the mass of MOH is recorded as m2, and the total mass of ammonia, M2S, MClO3 and hydrogen peroxide is recorded as m3, and m1:m2:m3 is 1:(1-4):(0.6-5.5). Further preferably, the impurity remover includes NiCO3, NaOH and ammonia, and the mass ratio between the three is 1:(0.8-6):(0.3-8), preferably 1:(1-4):(0.6-2), more preferably 1:(2-3):(2-3), such as 1:2:3, 1:3:2, 1:4:0.6, 1:1:0.6, etc.; or, the impurity remover includes NiCO3, NaOH, ammonia and hydrogen peroxide, and the mass ratio between the four is 1:(1-4):(0.6-2): (0.3-0.6), preferably 1: (2-3): (0.6-2): (0.3-0.6), such as 1:2:2:0.3, 1:3:0.6:0.6, 1:1:0.6:0.3, etc.; or, the impurity remover includes NiCO3, NaOH, ammonia water and Na2S, and the mass ratio between the four is 1: (1-4): (0.6-2): (0.5-2), preferably 1: (2-3): (0.6-2): (0.5-2), such as 1:3:0.6:2 , 1:2:2:0.5, 1:1:1:2, etc.; or, the impurity remover includes NiCO3, NaOH, ammonia water and NaClO3, and the mass ratio between the four is 1:(1-4):(0.6-2):(0.3-0.7), preferably 1:(2-3):(0.6-2):(0.3-0.7), such as 1:2:2:0.3, 1:3:0.6:0.7, 1:1:1:0.7, etc.; or, the impurity remover includes NiCO3, NaOH, ammonia water, Na2 S, NaClO3 and hydrogen peroxide, and the mass ratio between the six is ​​1:(1-4):(0.6-2):(0.5-2):(0.3-0.7):(0.3-0.6), preferably 1:(2-3):(1-1.5):(0.5-1):(0.3-0.7):(0.4-0.6), such as 1:2:1:0.6:0.5:0.5, 1:3:1.5:0.8:0.5:0.4, 1:1:2:0.3:0.7:0.3, etc. Using the above impurity removers, the components have better synergistic effects and stronger precipitation and separation capabilities for impurity ions.

[0032] The above-mentioned impurity remover can be added to the acid leaching solution alone to react. Of course, in order to make the impurity removal environment more stable and the reaction more complete, in a preferred embodiment, after adjusting the pH value of the acid leaching solution to 4-5.5 (such as 4, 5, 5.5, etc.) in step (b), it is first filtered, and then the impurity remover is added to the filtrate, and the impurity remover is added to the filtrate in the form of an aqueous solution to carry out the impurity removal reaction. More preferably, the mass concentration of the impurity remover in the aqueous solution is 10-30%, such as 10%, 15%, 20%, 25%, 30%, etc. The impurity removal reaction is more complete by controlling the concentration of the impurity remover aqueous solution and the dosage relationship between the impurity remover and the acid leaching solution within the above range.

[0033] In order to further improve the reaction efficiency, in a preferred embodiment, during the impurity removal reaction, the reaction temperature is 70-90°C, such as 70°C, 80°C, and 90°C, and the reaction time is 1-4h, such as 1h, 2h, 3h, and 4h; preferably, the impurity removal reaction is carried out under stirring, and the stirring speed is 100-300rpm / min, such as 100rpm / min, 120rpm / min, 150rpm / min, 180rpm / min, 200rpm / min, 250rpm / min, 280rpm / min, and 300rpm / min.

[0034] The step of adjusting the pH of the acid leaching solution to 4-5.5 is intended to provide a stable acidic and alkaline environment for the subsequent impurity removal reaction, thereby ensuring the selective precipitation of impurity ions by the impurity remover. In a specific implementation, preferably, sodium hydroxide aqueous solution and / or potassium hydroxide aqueous solution are used as pH adjusters, and more preferably, the mass concentrations of sodium hydroxide aqueous solution and potassium hydroxide aqueous solution are 5-20%, for example, 5%, 10%, 15%, or 20%, respectively.

[0035] The impurity removal method provided by the present invention is effective for acid leaching solutions of retired lithium-ion battery cathode materials. To further improve the separation of valuable metals from impurity ions, in a preferred embodiment, the mass concentration of lithium ions in the acid leaching solution is 3-16 g / L, the mass concentration of nickel ions is 13-70 g / L, the mass concentration of cobalt ions is 7-27 g / L, and the mass concentration of manganese ions is 30-100 g / L. The mass concentration of each impurity ion is 0.0001-7 g / L, respectively. Preferably, in the acid leaching solution, the mass concentration of lithium ions is 7-13 g / L, the mass concentration of nickel ions is 14-20 g / L, the mass concentration of cobalt ions is 14-17 g / L, the mass concentration of manganese ions is 60-98 g / L, the mass concentration of copper ions is 0.2-0.5 g / L, the mass concentration of aluminum ions is 6-8 g / L, the mass concentration of iron ions is 0.2-1.2 g / L, the mass concentration of calcium ions is 0.05-0.5 g / L, and the mass concentration of magnesium ions is 0.02-1.2 g / L.

[0036] The above acid leaching process can be carried out using common methods in the art. Of course, in order to further improve the acid leaching effect, in a preferred embodiment, step (a) uses sulfuric acid to leach the positive electrode of the retired lithium-ion battery, and the mass concentration of the sulfuric acid is preferably 10-70%, such as 10%, 20%, 30%, 35%, 40%, 50%, 60%, or 70%; the ratio of the number of moles of H2SO4 in the sulfuric acid to the number of moles of the metal in the positive electrode is (0.7-2):1, such as (0.7-1.5):1, for example 0.7:1, 1:1, 1.2:1, or 1.5:1.

[0037] After the impurity removal reaction, the impurity ions are separated from the valuable metal ions (lithium ions, nickel ions, cobalt ions, manganese ions, etc.) in the solution in the form of a precipitate. In actual operation, the method preferably includes a filtration step after the impurity removal step, and the treatment temperature during the filtration step is not less than 60°C. Hot filtration can more effectively separate the impurity ions.

[0038] The present invention also relates to an impurity remover comprising NiCO3 and MOH. Optionally, the impurity remover further comprises at least one of ammonia water, M2S, MClO3, and hydrogen peroxide, where M is Na or K. Adding the impurity remover to a positive electrode material acid leaching solution and reacting the mixture can achieve the purpose of removing impurity ions such as copper ions, aluminum ions, iron ions, calcium ions, and magnesium ions at one time, thereby producing a precursor solution suitable for preparing a ternary positive electrode material.

[0039] Preferably, the mass ratio of NiCO3 and MOH is 1:(0.8-6), more preferably 1:(1-4); preferably, MOH is NaOH; preferably, M2S is Na2S; preferably, MClO3 is NaClO3; more preferably, the mass of NiCO3 is recorded as m1, the mass of MOH is recorded as m2, the total mass of ammonia water, M2S, MClO3 and hydrogen peroxide is recorded as m3, and m1:m2:m3 is 1:(0.8-6):(0.3-8), more preferably 1:(1-4):(0.6-5.5); further preferably, the impurity remover includes NiCO3, NaOH and ammonia water, and the mass ratio between the three is 1:(1-4):(0.6-2); or, the impurity remover includes NiCO3, NaOH, ammonia water, Water and hydrogen peroxide, and the mass ratio among them is 1:(1-4):(0.6-2):(0.3-0.6); or, the impurity remover includes NiCO3, NaOH, ammonia water and Na2S, and the mass ratio among them is 1:(1-4):(0.6-2):(0.5-2); or, the impurity remover includes NiCO3, NaOH, ammonia water and NaClO3, and the mass ratio among them is 1:(1-4):(0.6-2):(0.3-0.7); or, the impurity remover includes NiCO3, NaOH, ammonia water, Na2S, NaClO3 and hydrogen peroxide, and the mass ratio among them is 1:(1-4):(0.6-2):(0.5-2):(0.3-0.7):(0.3-0.6).

[0040] According to another aspect of the present invention, an aqueous solution of the above-mentioned impurity remover is also provided. Preferably, the mass concentration of the aqueous solution of the impurity remover is 10-30%.

[0041] According to another aspect of the present invention, a solution is also provided, which is prepared by the above method. The solution has a high concentration of lithium ions, nickel ions, cobalt ions and manganese ions, and the content of impurity ions is very low, and can be directly used as a precursor raw material for ternary positive electrode materials. Preferably, the solution contains lithium ions at a concentration of 7.5 to 9.5 g / L, nickel ions at a concentration of 14.5 to 17 g / L, cobalt ions at a concentration of 11.5 to 15 g / L, manganese ions at a concentration of 65 to 82 g / L, and impurity ions at a concentration of less than 0.2 g / L. More preferably, the solution contains lithium ions at a concentration of 7.9 to 9.3 g / L, nickel ions at a concentration of 15.1 to 16.4 g / L, cobalt ions at a concentration of 12.0 to 13.9 g / L, manganese ions at a concentration of 66.5 to 80.1 g / L, and impurity ions at a concentration of less than 0.1 g / L. Even more preferably, the impurity ion concentration is less than 0.05 g / L, 0.02 g / L, or 0.015 g / L. The impurity ions include at least one of copper ions, aluminum ions, iron ions, calcium ions, magnesium ions, lead ions, chromium ions, cadmium ions, and zinc ions.

[0042] The present application is further described in detail below with reference to specific embodiments. These embodiments should not be construed as limiting the scope of protection claimed in this application.

[0043] Unless otherwise specified, the reagents used in this example are all commercially available.

[0044] Example 1

[0045] The metals in the positive electrode (ternary material) of waste lithium batteries were leached using 35% sulfuric acid, with the ratio of the moles of H2SO4 in the sulfuric acid to the moles of the metals in the positive electrode controlled at 1.5:1. This produced a mixed sulfate solution system with a mass concentration of 9.6 g / L lithium ions, 16.3 g / L nickel ions, 15.3 g / L cobalt ions, 97.5 g / L manganese ions, and other impurity metals such as 0.3 g / L Cu, 6.1 g / L Al, 0.5 g / L Fe, 0.07 g / L Ca, and 0.08 g / L Mg. A 20% NaOH solution was slowly added to the sulfate solution system, and the solution was filtered after adjusting the pH to 5.1. An impurity remover was then added to the filtrate to raise the pH to 6.5. The impurity remover is a 10% aqueous solution of NiCO₃, NaOH, and ammonia in a 1:2:3 ratio. After addition, the solution is heated in an 80°C water bath with stirring (150 rpm / min) for 2 hours. After hot filtration, a solution of precursor material for preparing ternary cathode materials is obtained.

[0046] After testing, the removal rates of Cu, Al, Fe, Ca and Mg were 97.6%, 99.9%, 99.8%, 99.6% and 99.4% respectively. In the obtained positive electrode precursor raw material solution, the concentrations of Li, Ni, Co and Mn were 8.7 g / L, 15.8 g / L, 12.4 g / L and 73.2 g / L respectively, and the concentrations of impurity ions Cu, Al, Fe, Ca and Mg were 0.007 g / L, 0.005 g / L, 0.0008 g / L, 0.0003 g / L and 0.0005 g / L respectively.

[0047] Example 2

[0048] The only difference from Example 1 is that the impurity remover is an aqueous solution formed by dissolving NiCO3, NaOH and ammonia in water, and the mass ratio of NiCO3, NaOH and ammonia is 1:3:2.

[0049] After testing, the removal rates of Cu, Al, Fe, Ca, and Mg were 97.0%, 99.9%, 99.9%, 99.3%, and 99.6%, respectively. In the obtained positive electrode precursor raw material solution, the concentrations of Li, Ni, Co, and Mn were 8.9 g / L, 16.1 g / L, 13.5 g / L, and 76.3 g / L, and the concentrations of impurity ions Cu, Al, Fe, Ca, and Mg were 0.009 g / L, 0.006 g / L, 0.0005 g / L, 0.0005 g / L, and 0.0003 g / L. This embodiment also uses the preferred mass ratio of NiCO3, NaOH, and ammonia water of the present invention, and has excellent impurity removal effect.

[0050] Example 3

[0051] The only difference from Example 1 is that the impurity remover is an aqueous solution formed by dissolving NiCO 3 , NaOH and ammonia in water, and the mass ratio of NiCO 3 , NaOH and ammonia is 1:4:0.6.

[0052] Testing showed that the removal rates of Cu, Al, Fe, Ca, and Mg were 96.7%, 99.9%, 99.8%, 98.3%, and 98.8%, respectively. The concentrations of Li, Ni, Co, and Mn in the resulting precursor solution were 8.5g / L, 16.4g / L, 13.2g / L, and 79.4g / L, respectively. The concentrations of impurity ions Cu, Al, Fe, Ca, and Mg were 0.01g / L, 0.009g / L, 0.0011g / L, 0.0012g / L, and 0.001g / L, respectively. This method demonstrates excellent impurity removal performance.

[0053] Example 4

[0054] The only difference from Example 1 is that the impurity remover is an aqueous solution formed by dissolving NiCO 3 , NaOH and ammonia in water, and the mass ratio of NiCO 3 , NaOH and ammonia is 1:1:0.6.

[0055] Testing showed that the removal rates of Cu, Al, Fe, Ca, and Mg were 96.3%, 99.8%, 99.7%, 98.7%, and 98.8%, respectively. The concentrations of Li, Ni, Co, and Mn in the resulting precursor solution were 8.1 g / L, 15.8 g / L, 13.0 g / L, and 79.8 g / L, respectively. The concentrations of impurity ions Cu, Al, Fe, Ca, and Mg were 0.011 g / L, 0.012 g / L, 0.0015 g / L, 0.0009 g / L, and 0.001 g / L, respectively. This method demonstrates excellent impurity removal performance.

[0056] Example 5

[0057] The only difference from Example 1 is that the impurity remover is an aqueous solution formed by dissolving NiCO 3 , NaOH and ammonia in water, and the mass ratio of NiCO 3 , NaOH and ammonia is 1:1:0.3.

[0058] After testing, the removal rates of Cu, Al, Fe, Ca, and Mg were 95.0%, 99.8%, 99.6%, 97.6%, and 97.4%, respectively. In the resulting precursor solution, the concentrations of Li, Ni, Co, and Mn were 8.5 g / L, 16.4 g / L, 13.2 g / L, and 79.4 g / L, and the concentrations of impurity ions Cu, Al, Fe, Ca, and Mg were 0.015 g / L, 0.01 g / L, 0.002 g / L, 0.0017 g / L, and 0.0021 g / L, respectively. This example changed the mass ratio of NiCO3, NaOH, and ammonia water, but the mass ratio was not within the preferred range. The impurity removal effect was good, but slightly worse than that of Examples 1 to 4.

[0059] Example 6

[0060] The only difference from Example 1 is that the impurity remover is an aqueous solution formed by dissolving NiCO 3 and NaOH in water, and the mass ratio of NiCO 3 to NaOH is 1:2.

[0061] After testing, the removal rates of Cu, Al, Fe, Ca, and Mg were 95.7%, 99.7%, 99.6%, 97.9%, and 97.8%, respectively. In the resulting precursor solution, the concentrations of Li, Ni, Co, and Mn were 8.7 g / L, 16.6 g / L, 13.4 g / L, and 79.7 g / L, respectively. The concentrations of the impurity ions Cu, Al, Fe, Ca, and Mg were 0.013 g / L, 0.018 g / L, 0.0021 g / L, 0.0015 g / L, and 0.0018 g / L, respectively. This embodiment uses only a de-impurity agent consisting of NiCO3 and NaOH, and the de-impurity effect is good, but slightly worse than that of Example 1.

[0062] Example 7

[0063] The only difference from Example 1 is that the impurity remover is an aqueous solution formed by dissolving NiCO 3 and NaOH in water, and the mass ratio of NiCO 3 to NaOH is 1:3.

[0064] After testing, the removal rates of Cu, Al, Fe, Ca, and Mg were 95.3%, 99.8%, 99.7%, 98.1%, and 97.9%, respectively. In the resulting precursor solution, the concentrations of Li, Ni, Co, and Mn were 8.4 g / L, 16.3 g / L, 13.1 g / L, and 79.1 g / L, respectively. The concentrations of the impurity ions Cu, Al, Fe, Ca, and Mg were 0.014 g / L, 0.01 g / L, 0.0015 g / L, 0.0013 g / L, and 0.0017 g / L, respectively. This embodiment only uses a de-impurity agent consisting of NiCO3 and NaOH, and the ratio of the two is adjusted. The de-impurity effect is good, but slightly worse than that of Examples 1 and 2.

[0065] Example 8

[0066] The only difference from Example 1 is that the impurity remover is an aqueous solution formed by dissolving NiCO 3 and NaOH in water, and the mass ratio of NiCO 3 to NaOH is 1:1.

[0067] After testing, the removal rates of Cu, Al, Fe, Ca, and Mg were 95.0%, 99.6%, 99.6%, 97.0%, and 97.6%, respectively. In the resulting precursor solution, the concentrations of Li, Ni, Co, and Mn were 8.7 g / L, 16.3 g / L, 13.6 g / L, and 79.5 g / L, and the concentrations of the impurity ions Cu, Al, Fe, Ca, and Mg were 0.015 g / L, 0.023 g / L, 0.0020 g / L, 0.0021 g / L, and 0.0019 g / L, respectively. This embodiment uses only a de-impurity agent consisting of NiCO3 and NaOH, and the ratio of the two is not the most preferred ratio. The de-impurity effect is good, but slightly worse than that of Examples 6 and 7.

[0068] Example 9

[0069] The only difference from Example 1 is that the impurity remover is an aqueous solution formed by dissolving NiCO 3 and NaOH in water, and the mass ratio of NiCO 3 to NaOH is 1:4.

[0070] After testing, the removal rates of Cu, Al, Fe, Ca, and Mg were 94.3%, 99.7%, 99.5%, 97.1%, and 97.5%, respectively. In the resulting precursor solution, the concentrations of Li, Ni, Co, and Mn were 8.2 g / L, 16.2 g / L, 13.4 g / L, and 78.9 g / L, and the concentrations of impurity ions Cu, Al, Fe, Ca, and Mg were 0.017 g / L, 0.021 g / L, 0.0023 g / L, 0.002 g / L, and 0.002 g / L, respectively. This embodiment uses only a de-impurity agent consisting of NiCO3 and NaOH, and the ratio of the two is not the most preferred ratio. The de-impurity effect is good, but slightly worse than that of Examples 6 and 7.

[0071] Example 10

[0072] The only difference from Example 1 is that the impurity remover is an aqueous solution formed by dissolving NiCO3, NaOH, ammonia water, and hydrogen peroxide in water, and the mass ratio of NiCO3, NaOH, ammonia water, and hydrogen peroxide is 1:2:2:0.3.

[0073] After testing, the removal rates of Cu, Al, Fe, Ca, and Mg were 98.0%, 99.9%, 99.9%, 99.4%, and 99.6%, respectively. In the resulting precursor solution, the concentrations of Li, Ni, Co, and Mn were 9.1 g / L, 16.0 g / L, 13.7 g / L, and 80.1 g / L, and the concentrations of impurity ions Cu, Al, Fe, Ca, and Mg were 0.006 g / L, 0.007 g / L, 0.0005 g / L, 0.0004 g / L, and 0.0003 g / L, respectively. This embodiment uses an impurity remover consisting of NiCO3, NaOH, ammonia water, and hydrogen peroxide, and the ratio between them is the preferred ratio, which has excellent impurity removal effect.

[0074] Example 11

[0075] The only difference from Example 1 is that the impurity remover is an aqueous solution formed by dissolving NiCO3, NaOH, ammonia water, and hydrogen peroxide in water, and the mass ratio of NiCO3, NaOH, ammonia water, and hydrogen peroxide is 1:3:0.6:0.6.

[0076] After testing, the removal rates of Cu, Al, Fe, Ca, and Mg were 99%, 99.9%, 99.9%, 99.6%, and 99.9%, respectively. In the obtained precursor solution, the concentrations of Li, Ni, Co, and Mn were 9.2 g / L, 15.7 g / L, 13.9 g / L, and 76.3 g / L, and the concentrations of impurity ions Cu, Al, Fe, Ca, and Mg were 0.003 g / L, 0.002 g / L, 0.0002 g / L, 0.0003 g / L, and 0.0001 g / L, respectively. This embodiment uses an impurity remover consisting of NiCO3, NaOH, ammonia water, and hydrogen peroxide, and the ratio between them is the preferred ratio, which has excellent impurity removal effect.

[0077] Example 12

[0078] The only difference from Example 1 is that the impurity remover is an aqueous solution formed by dissolving NiCO3, NaOH, ammonia water, and hydrogen peroxide in water, and the mass ratio of NiCO3, NaOH, ammonia water, and hydrogen peroxide is 1:1:0.6:0.3.

[0079] After testing, the removal rates of Cu, Al, Fe, Ca, and Mg were 95.7%, 99.7%, 99.7%, 97.7%, and 98.3%, respectively. In the resulting precursor solution, the concentrations of Li, Ni, Co, and Mn were 9.3 g / L, 15.4 g / L, 12.4 g / L, and 77.5 g / L, respectively. The concentrations of the impurity ions Cu, Al, Fe, Ca, and Mg were 0.013 g / L, 0.018 g / L, 0.0013 g / L, 0.0016 g / L, and 0.0014 g / L, respectively. The impurity removal effect was good, but slightly worse than that of Examples 11 and 12.

[0080] Example 13

[0081] The only difference from Example 1 is that the impurity remover is an aqueous solution formed by dissolving NiCO3, NaOH, ammonia water, and Na2S in water, and the mass ratio of NiCO3, NaOH, ammonia water, and Na2S is 1:2:2:0.5.

[0082] After testing, the removal rates of Cu, Al, Fe, Ca, and Mg were 98.3%, 99.9%, 99.9%, 99.4%, and 99.8%, respectively. In the obtained precursor solution, the concentrations of Li, Ni, Co, and Mn were 8.9 g / L, 16.0 g / L, 13.4 g / L, and 68.5 g / L, and the concentrations of impurity ions Cu, Al, Fe, Ca, and Mg were 0.005 g / L, 0.006 g / L, 0.0004 g / L, 0.0004 g / L, and 0.0002 g / L, respectively. This embodiment uses an impurity remover consisting of NiCO3, NaOH, ammonia water, and Na2S, and the ratio between them is the preferred ratio, which has excellent impurity removal effect.

[0083] Example 14

[0084] The only difference from Example 1 is that the impurity remover is an aqueous solution formed by dissolving NiCO3, NaOH, ammonia water, and Na2S in water, and the mass ratio of NiCO3, NaOH, ammonia water, and Na2S is 1:3:0.6:2.

[0085] After testing, the removal rates of Cu, Al, Fe, Ca, and Mg were 98.7%, 99.9%, 99.9%, 99.3%, and 99.8%, respectively. In the obtained precursor solution, the concentrations of Li, Ni, Co, and Mn were 8.8 g / L, 15.6 g / L, 13.1 g / L, and 67.7 g / L, and the concentrations of impurity ions Cu, Al, Fe, Ca, and Mg were 0.004 g / L, 0.005 g / L, 0.0003 g / L, 0.0005 g / L, and 0.0002 g / L, respectively. This embodiment uses an impurity remover consisting of NiCO3, NaOH, ammonia water, and Na2S, and the ratio between them is the preferred ratio, which has excellent impurity removal effect.

[0086] Example 15

[0087] The only difference from Example 1 is that the impurity remover is an aqueous solution formed by dissolving NiCO3, NaOH, ammonia water, and Na2S in water, and the mass ratio of NiCO3, NaOH, ammonia water, and Na2S is 1:1:1:2.

[0088] After testing, the removal rates of Cu, Al, Fe, Ca, and Mg were 97.7%, 99.9%, 99.9%, 99.0%, and 99.4%, respectively. In the obtained precursor solution, the concentrations of Li, Ni, Co, and Mn were 8.3 g / L, 15.3 g / L, 13.4 g / L, and 66.5 g / L, and the concentrations of impurity ions Cu, Al, Fe, Ca, and Mg were 0.007 g / L, 0.009 g / L, 0.0006 g / L, 0.0007 g / L, and 0.0005 g / L, respectively. This embodiment has an excellent impurity removal effect, but is slightly inferior to Examples 13 and 14.

[0089] Example 16

[0090] The only difference from Example 1 is that the impurity remover is an aqueous solution formed by dissolving NiCO3, NaOH, ammonia water, and NaClO3 in water, and the mass ratio of NiCO3, NaOH, ammonia water, and NaClO3 is 1:2:2:0.3.

[0091] After testing, the removal rates of Cu, Al, Fe, Ca, and Mg were 98.3%, 99.9%, 99.9%, 99.4%, and 99.8%, respectively. In the obtained precursor solution, the concentrations of Li, Ni, Co, and Mn were 9.0 g / L, 15.7 g / L, 13.1 g / L, and 70.6 g / L, and the concentrations of impurity ions Cu, Al, Fe, Ca, and Mg were 0.005 g / L, 0.005 g / L, 0.0006 g / L, 0.0004 g / L, and 0.0002 g / L, respectively. This embodiment uses an impurity remover consisting of NiCO3, NaOH, ammonia water, and NaClO3, and the ratio between them is the preferred ratio, which has excellent impurity removal effect.

[0092] Example 17

[0093] The only difference from Example 1 is that the impurity remover is an aqueous solution formed by dissolving NiCO3, NaOH, ammonia water, and NaClO3 in water, and the mass ratio of NiCO3, NaOH, ammonia water, and NaClO3 is 1:3:0.6:0.7.

[0094] After testing, the removal rates of Cu, Al, Fe, Ca, and Mg were 98.0%, 99.9%, 99.9%, 99.3%, and 99.6%, respectively. In the obtained precursor solution, the concentrations of Li, Ni, Co, and Mn were 8.5g / L, 16.1g / L, 13.5g / L, and 75.4g / L, and the concentrations of impurity ions Cu, Al, Fe, Ca, and Mg were 0.006g / L, 0.005g / L, 0.0006g / L, 0.0005g / L, and 0.0003g / L, respectively. This embodiment uses an impurity remover consisting of NiCO3, NaOH, ammonia water, and NaClO3, and the ratio between them is the preferred ratio, which has excellent impurity removal effect.

[0095] Example 18

[0096] The only difference from Example 1 is that the impurity remover is an aqueous solution formed by dissolving NiCO3, NaOH, ammonia water, and NaClO3 in water, and the mass ratio of NiCO3, NaOH, ammonia water, and NaClO3 is 1:1:1:0.7.

[0097] After testing, the removal rates of Cu, Al, Fe, Ca, and Mg were 96.3%, 99.8%, 99.7%, 97.4%, and 98.9%, respectively. In the obtained precursor solution, the concentrations of Li, Ni, Co, and Mn were 8.7 g / L, 15.7 g / L, 13.8 g / L, and 77.1 g / L, and the concentrations of impurity ions Cu, Al, Fe, Ca, and Mg were 0.011 g / L, 0.013 g / L, 0.0017 g / L, 0.0018 g / L, and 0.0009 g / L, respectively. This embodiment has a good impurity removal effect, but is slightly worse than Examples 16 and 17.

[0098] Example 19

[0099] The only difference from Example 1 is that the impurity remover is an aqueous solution formed by dissolving NiCO3, NaOH, ammonia water, Na2S, NaClO3 and hydrogen peroxide in water, and the mass ratio of NiCO3, NaOH, ammonia water, Na2S, NaClO3 and hydrogen peroxide is 1:2:1:0.6:0.5:0.5.

[0100] After testing, the removal rates of Cu, Al, Fe, Ca, and Mg were 98.3%, 99.9%, 99.9%, 99.4%, and 99.8%, respectively. In the resulting precursor solution, the concentrations of Li, Ni, Co, and Mn were 7.9 g / L, 15.4 g / L, 13.1 g / L, and 76.5 g / L, and the concentrations of the impurity ions Cu, Al, Fe, Ca, and Mg were 0.005 g / L, 0.004 g / L, 0.0005 g / L, 0.0004 g / L, and 0.0002 g / L. This embodiment uses an impurity remover consisting of NiCO3, NaOH, ammonia water, Na2S, NaClO3, and hydrogen peroxide, and the ratio between them is the preferred ratio, which has excellent impurity removal effect.

[0101] Example 20

[0102] The only difference from Example 1 is that the impurity remover is an aqueous solution formed by dissolving NiCO3, NaOH, ammonia water, Na2S, NaClO3 and hydrogen peroxide in water, and the mass ratio of NiCO3, NaOH, ammonia water, Na2S, NaClO3 and hydrogen peroxide is 1:3:1.5:0.8:0.5:0.4.

[0103] After testing, the removal rates of Cu, Al, Fe, Ca, and Mg were 99.0%, 99.9%, 99.9%, 99.6%, and 99.8%, respectively. In the resulting precursor solution, the concentrations of Li, Ni, Co, and Mn were 8.3 g / L, 15.8 g / L, 13.7 g / L, and 75.5 g / L, and the concentrations of impurity ions Cu, Al, Fe, Ca, and Mg were 0.003 g / L, 0.004 g / L, 0.0005 g / L, 0.0003 g / L, and 0.0002 g / L, respectively. This embodiment uses an impurity remover consisting of NiCO3, NaOH, ammonia water, Na2S, NaClO3, and hydrogen peroxide, and the ratios between them are optimal, resulting in excellent impurity removal effect.

[0104] Example 21

[0105] The only difference from Example 1 is that the impurity remover is an aqueous solution formed by dissolving NiCO3, NaOH, ammonia water, Na2S, NaClO3 and hydrogen peroxide in water, and the mass ratio of NiCO3, NaOH, ammonia water, Na2S, NaClO3 and hydrogen peroxide is 1:1:2:0.3:0.7:0.3.

[0106] After testing, the removal rates of Cu, Al, Fe, Ca, and Mg were 97.0%, 99.8%, 99.8%, 98.9%, and 98.9%, respectively. In the obtained precursor solution, the concentrations of Li, Ni, Co, and Mn were 8.5 g / L, 16.1 g / L, 12.8 g / L, and 78.3 g / L, and the concentrations of impurity ions Cu, Al, Fe, Ca, and Mg were 0.009 g / L, 0.012 g / L, 0.0011 g / L, 0.0008 g / L, and 0.0009 g / L, respectively. The impurity removal effect of this embodiment is good, but slightly worse than that of Examples 19 and 20.

[0107] Example 22

[0108] The only difference from Example 1 is that a 5% mass concentration of NaOH solution is slowly added to the sulfate solution system, the solution is filtered after adjusting the pH to 4, and then an impurity remover is added to the filtrate to adjust the pH to 5.6. The impurity remover is an aqueous solution formed by dissolving NiCO3, NaOH, and ammonia in water. The mass ratio of NiCO3, NaOH, and ammonia is 1:2:3, and the mass concentration of the aqueous solution is 30%. After addition, heat and stir in a water bath at 90°C (100 rpm / min) for 1 hour. After filtering while hot, a precursor solution for preparing a ternary positive electrode material is obtained.

[0109] After testing, the removal rates of Cu, Al, Fe, Ca, and Mg were 98.0%, 99.9%, 99.9%, 99.4%, and 99.6%, respectively. In the resulting precursor solution, the concentrations of Li, Ni, Co, and Mn were 8.0 g / L, 15.5 g / L, 12.3 g / L, and 76.5 g / L, respectively. The concentrations of the impurity ions Cu, Al, Fe, Ca, and Mg were 0.006 g / L, 0.005 g / L, 0.0006 g / L, 0.0004 g / L, and 0.0003 g / L, respectively. This example, based on Example 1, adjusted the pH of steps (b) and (c) within the scope of the present invention, achieving excellent impurity removal results.

[0110] Example 23

[0111] The only difference from Example 1 is that a 5% mass concentration of NaOH solution is slowly added to the sulfate solution system, the solution is filtered after adjusting the pH to 4, and then an impurity remover is added to the filtrate to adjust the pH to 5.6. The impurity remover is an aqueous solution formed by dissolving NiCO3, NaOH, and ammonia in water. The mass ratio of NiCO3, NaOH, and ammonia is 1:2:3, and the mass concentration of the aqueous solution is 10%. After addition, heat and stir in a water bath at 70°C (300rpm / min) for 4 hours. After filtering while hot, a precursor solution for preparing a ternary positive electrode material is obtained.

[0112] After testing, the removal rates of Cu, Al, Fe, Ca, and Mg were 98.3%, 99.9%, 99.9%, 99.3%, and 99.5%, respectively. In the obtained precursor solution, the concentrations of Li, Ni, Co, and Mn were 8.2 g / L, 15.3 g / L, 12.7 g / L, and 78.2 g / L, and the concentrations of impurity ions Cu, Al, Fe, Ca, and Mg were 0.005 g / L, 0.006 g / L, 0.0004 g / L, 0.0005 g / L, and 0.0004 g / L, respectively. This embodiment has excellent impurity removal effect.

[0113] Example 24

[0114] The only difference from Example 1 is that a 5% mass concentration of NaOH solution is slowly added to the sulfate solution system, the solution is filtered after adjusting the pH to 4, and then an impurity remover is added to the filtrate to adjust the pH to 5.5. The impurity remover is an aqueous solution formed by dissolving NiCO3, NaOH, and ammonia in water. The mass ratio of NiCO3, NaOH, and ammonia is 1:2:3, and the mass concentration of the aqueous solution is 30%. After addition, heat and stir in a water bath at 60°C (300rpm / min) for 4 hours. After filtering while hot, a precursor solution for preparing a ternary positive electrode material is obtained.

[0115] After testing, the removal rates of Cu, Al, Fe, Ca, and Mg were 96.5%, 99.4%, 99.2%, 99.0%, and 99.2%, respectively. In the resulting precursor solution, the concentrations of Li, Ni, Co, and Mn were 7.8 g / L, 15.1 g / L, 12.2 g / L, and 76.2 g / L, respectively. The concentrations of the impurity ions Cu, Al, Fe, Ca, and Mg were 0.098 g / L, 0.009 g / L, 0.0009 g / L, 0.0008 g / L, and 0.0007 g / L, respectively. The reaction temperature in this example was slightly lower, and the impurity removal effect was slightly worse than that of Examples 1 and 23.

[0116] Comparative Example 1

[0117] The difference from Example 1 is that: after adjusting the pH value of the acid leaching solution to 6, an impurity remover is added to remove impurities.

[0118] After testing, the removal rates of Cu, Al, Fe, Ca, and Mg were 73.3%, 85.2%, 98.8%, 74.3%, and 88.6%, respectively. The concentrations of Li, Ni, Co, and Mn in the resulting precursor solution were 8.6 g / L, 13.1 g / L, 10.2 g / L, and 60.8 g / L, respectively. The concentrations of the impurity ions Cu, Al, Fe, Ca, and Mg were 0.08 g / L, 0.9 g / L, 0.06 g / L, 0.018 g / L, and 0.009 g / L, respectively. In this comparative example, the pH value of the acid leaching solution was not adjusted appropriately before impurity removal, resulting in a significant decrease in the impurity removal effect.

[0119] Comparative Example 2

[0120] The difference from Example 1 is that: the pH value is adjusted before filtration, and no impurity removal is performed using an impurity remover.

[0121] Testing revealed that the removal rates for Cu, Al, Fe, Ca, and Mg were 33.3%, 82.0%, 60.0%, 57.1%, and 87.5%, respectively. The resulting precursor solution contained 8.4 g / L, 13.5 g / L, 11.2 g / L, and 68.7 g / L of Li, Ni, Co, and Mn, respectively. The concentrations of the impurity ions Cu, Al, Fe, Ca, and Mg were 0.2 g / L, 1.1 g / L, 0.2 g / L, 0.03 g / L, and 0.01 g / L, respectively. In this comparative example, the pH of the acid leaching solution was adjusted, but no impurity removal was performed. Consequently, the resulting solution contained a very high level of impurities.

[0122] From the above data, it can be seen that the method in the embodiment of the present invention is used to remove impurities from the positive electrode acid leaching solution of retired lithium-ion batteries, which has high selectivity and obtains a relatively pure ternary positive electrode material precursor solution.

[0123] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A method for removing impurities in the recovery process of valuable metals from retired lithium-ion batteries, characterized in that: The method comprises the following steps: (a) leaching the cathode material of the retired lithium-ion battery with an acid solution to obtain an acid leaching solution; wherein the acid leaching solution contains lithium ions, nickel ions, cobalt ions, manganese ions, and impurity ions, wherein the impurity ions include copper ions, aluminum ions, iron ions, calcium ions, and magnesium ions, and optionally other ions, wherein the other ions include lead ions, chromium ions, cadmium ions, or zinc ions; (b) adjusting the pH value of the acid extract to 4-5.5; (c) adding an impurity remover to the mixture until the pH value reaches 5.6 to 7, and performing an impurity removal reaction to remove the impurity ions; during the impurity removal reaction, the reaction temperature is 70 to 90° C., and the reaction time is 1 to 4 hours; the impurity removal reaction is performed under stirring at a stirring speed of 100 to 300 rpm / min; Wherein, the impurity remover comprises NiCO3, NaOH and ammonia water, and the mass ratio of the three is 1: (1-4): (0.6-2); or, The impurity remover comprises NiCO3, NaOH, ammonia water and hydrogen peroxide, and the mass ratio of the four is 1: (1-4): (0.6-2): (0.3-0.6); or, The impurity remover comprises NiCO3, NaOH, ammonia water and Na2S, and the mass ratio of the four is 1: (1-4): (0.6-2): (0.5-2); or, The impurity remover comprises NiCO3, NaOH, ammonia water and NaClO3, and the mass ratio of the four is 1: (1-4): (0.6-2): (0.3-0.7); or, The impurity remover comprises NiCO3, NaOH, ammonia water, Na2S, NaClO3 and hydrogen peroxide, and the mass ratio of the six is ​​1:(1-4):(0.6-2):(0.5-2):(0.3-0.7):(0.3-0.6); Step (b) adjusting the pH value of the acid leaching solution to 4-5.5, filtering the solution, and then adding the impurity remover to the filtrate. The impurity remover is added to the filtrate in the form of an aqueous solution to carry out the impurity removal reaction. The mass concentration of the impurity remover in the aqueous solution is 10-30%. The pH value of the acid leaching solution after step (b) is less than the pH value after the impurity remover is added in step (c), and the difference between the pH value after the impurity remover is added in step (c) and the pH value of the acid leaching solution after step (b) is 0.5-2.

2. The method according to claim 1, characterized in that In the step (b) of adjusting the pH value of the acid leaching solution, a sodium hydroxide aqueous solution and / or a potassium hydroxide aqueous solution are used as pH regulators; the mass concentrations of the sodium hydroxide aqueous solution and the potassium hydroxide aqueous solution are 5-20%, respectively.

3. The method according to claim 1 or 2, characterized in that In the acid leaching solution, the mass concentration of the lithium ions is 3-16 g / L, the mass concentration of the nickel ions is 13-70 g / L, the mass concentration of the cobalt ions is 7-27 g / L, the mass concentration of the manganese ions is 30-100 g / L, and the mass concentration of each impurity ion is 0.0001-7 g / L.

4. The method according to claim 3, characterized in that In the acid leaching solution, the mass concentration of the lithium ions is 7-13 g / L, the mass concentration of the nickel ions is 14-20 g / L, the mass concentration of the cobalt ions is 14-17 g / L, the mass concentration of the manganese ions is 60-98 g / L, the mass concentration of the copper ions is 0.2-0.5 g / L, the mass concentration of the aluminum ions is 6-7 g / L, the mass concentration of the iron ions is 0.2-1.2 g / L, the mass concentration of the calcium ions is 0.05-0.5 g / L, and the mass concentration of the magnesium ions is 0.02-1.2 g / L.

5. The method according to claim 3, characterized in that In step (a), sulfuric acid is used to leach the positive electrode material of the retired lithium-ion battery.

6. The method according to claim 5, characterized in that The mass concentration of the sulfuric acid is 10-70%, and the ratio of the molar number of H2SO4 in the sulfuric acid to the molar number of the metal in the positive electrode is (0.7-2):

1.

7. The method according to claim 1 or 2, characterized in that In step (c), an impurity remover is added to raise the pH to 5.6 to 6.5; and / or After step (c), the method further comprises a filtration step, and the treatment temperature in the filtration step is not lower than 60°C.