Method for preferentially removing manganese and recovering key metal from retired ternary lithium battery black powder

Abstract

The invention discloses a method for preferentially removing manganese and recovering key metals from black powder of a retired ternary lithium battery. According to the method, firstly, manganese-containing filter residues and a leaching solution with lithium, nickel and cobalt as main components are obtained through a secondary normal-temperature ammonia leaching process and solid-liquid separation, manganese in the retired ternary lithium battery black powder is preferentially removed, then cobalt and nickel in the leaching solution are sequentially recovered by adopting solvent extraction and a chemical precipitation method, and the cobalt and nickel in the leaching solution are recycled. And finally, adding a saturated sodium carbonate solution into the residual liquid to recover lithium in the form of lithium carbonate. The method avoids the problems of long separation and purification process and high extraction and separation cost in the prior art, has the advantages of short process, good separation effect, low cost, no secondary pollution and the like, realizes preferential removal of manganese in the retired ternary lithium battery black powder and recovery of lithium, nickel and cobalt key metals, and has a relatively good industrial application prospect.

Description

Technical Field

[0001] The present invention relates to the technical field of recycling retired power batteries, and in particular to a method for recycling key metals. Background Art

[0002] In recent years, in response to global warming and energy crises, countries have gradually controlled the use of traditional fossil fuels and carbon dioxide emissions, prompting lithium-ion batteries and other new energy equipment to gradually receive national and industry attention. Lithium-ion batteries are widely used, covering large electric vehicles and small electronic devices.

[0003] With the increasing demand and production of batteries, a large number of retired lithium batteries will inevitably be produced in the next few years. Efficient recycling of high-value metals in retired lithium batteries can alleviate the shortage of nickel and cobalt resources to a certain extent, and at the same time, it can also achieve a closed loop from production to recycling, and from recycling to production and reuse, which is closer to the requirements of low-carbon and environmental protection.

[0004] Ternary lithium batteries have a good application scenario in reality due to their high energy density and excellent low-temperature performance. The traditional method of using extractants to separate nickel, cobalt and manganese is efficient, but has the disadvantage of high cost. Therefore, the high cost problem still needs to be solved.

[0005] The existing leaching processes mainly include acid leaching, alkaline leaching, ammonia leaching and biological leaching. Since Ni, Co and Mn elements in ternary lithium batteries exist in the form of alkaline oxides and are easily soluble in acid, they can be recovered by acid leaching. This method is mainly based on inorganic acids, such as hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, etc. Acid leaching has the advantages of economic price and high leaching efficiency, but the large amount of waste acid liquid produced after acid leaching has high requirements for subsequent treatment equipment and requires high treatment costs. Alkaline leaching is based on the different pH values ​​of precipitation of different elements in ternary lithium batteries, which is suitable for separating elements with large pH differences. However, for ternary lithium batteries, the pH range of metal element precipitation is relatively close, and it is difficult to achieve efficient separation by simple alkaline leaching. Bioleaching mainly dissolves valuable metal ions through organic or inorganic acids produced during microbial metabolism. Although bioleaching is pollution-free and environmentally friendly, the strains are difficult to culture and survive, and have high requirements for the growth environment. In addition, the leaching time is long, the experimental conditions are relatively harsh, and it is difficult to apply in the industrial production stage.

[0006] The ammonia leaching method uses NH3·H2O, (NH4)2CO3, NH4HCO3 and the like as leaching agents, and H2O2 or Na2SO3 and the like as reducing agents. The principle is that nickel and cobalt have strong complexing ability with ammonia and their ammonia complexes are easily dissolved in ammonia solution, while manganese has poor complexing ability with ammonia and is removed as filter residue in an alkaline environment in the form of hydroxide precipitation. This method can form stable metal-ammine complexes at relatively low temperatures or room temperature, and it is expected to achieve efficient removal of manganese by exploring the optimal ratio.

[0007] Chinese patent CN115520909B uses ammonia water, ammonium bicarbonate and ammonium bisulfite to immerse the retired ternary lithium battery positive electrode material that has been calcined with starch for 4 to 6 hours, and then introduces carbon dioxide to pressurize it. Ammonium bisulfite is weakly acidic and will accelerate the consumption of bisulfite in the ammonia immersion system, reducing the effect of bisulfite as a reducing agent. Secondly, the reaction process has These two reasons indicate that bisulfite may not be the most suitable ammonia leaching system in the presence of ammonium bicarbonate.

[0008] Chinese patent CN115571925A uses sulfur dioxide to pass through ammonia water to obtain a mixed solution of ammonia water and ammonium sulfite, which is a good connection with the first step of passing sulfur dioxide for primary acid leaching pretreatment. However, this method has the disadvantages of redundant steps, high safety risks and no buffer. Ammonia leaching has high requirements for pH value. When the pH value is 9-10.5, manganese begins to precipitate. In order to better adjust the pH and avoid large fluctuations, a buffer is usually required. Secondly, the introduction of sulfur dioxide also requires professional delivery pipelines and strict management systems, which may increase the safety risks of the overall reaction process.

[0009] In summary, the existing ammonia leaching technology may have defects such as high separation cost and complicated steps, and it is urgent to develop an efficient, low-cost and environmentally friendly recovery technology. Summary of the invention

[0010] In view of the above problems, the main purpose of the present invention is to provide a method for preferentially removing manganese and recovering key metals in retired ternary lithium battery black powder containing lithium, nickel, cobalt and manganese. The method combines the secondary room temperature ammonia leaching process, the chemical precipitation method and the solvent extraction method to achieve the preferential removal of manganese in retired ternary lithium battery black powder and the recovery of key metals of lithium, nickel and cobalt, avoiding the problems of long separation and purification process and high extraction and separation cost in the prior art, and has the advantages of short process, good separation effect, low cost and no secondary pollution, and has good prospects for industrial application.

[0011] In the present invention, firstly, a secondary room temperature ammonia leaching process and solid-liquid separation are performed to obtain a manganese-containing filter residue and a leachate containing lithium, nickel and cobalt as main components, so as to achieve preferential removal of manganese in retired ternary lithium battery black powder, and then solvent extraction and chemical precipitation are used to sequentially recover cobalt and nickel in the leachate, and finally a saturated sodium carbonate solution is added to the remaining solution to recover lithium in the form of lithium carbonate. The specific technical scheme of the present invention is as follows.

[0012] A method for preferentially removing manganese from retired ternary lithium battery black powder and recovering key metals comprises the following steps:

[0013] (1) Dismantling retired ternary lithium batteries into battery cells, and obtaining black powder rich in lithium, nickel, cobalt and manganese elements through discharge, crushing and sorting pretreatment;

[0014] (2) adding an ammonia water-ammonium bicarbonate-hydrogen peroxide solution to the black powder obtained in step (1), stirring at room temperature, and performing a primary leaching; after the reaction is completed, performing solid-liquid separation to obtain a primary leaching filtrate containing lithium, nickel and cobalt and a filter residue containing metallic manganese as a main component;

[0015] (2) adding the filter residue obtained in step (2) into an ammonia water-ammonium bicarbonate-hydrogen peroxide solution, stirring at room temperature, and performing secondary leaching. After the reaction is completed, solid-liquid separation is performed to obtain a secondary leaching filtrate and a manganese-containing filter residue; the secondary leaching filtrate and the primary leaching filtrate are combined to obtain a leaching solution containing lithium, nickel and cobalt;

[0016] (4) adjusting the pH value of the leaching solution containing lithium, nickel and cobalt obtained in step (3), mixing it with a certain concentration of P507 extractant solution according to a certain aqueous phase / organic phase ratio, allowing them to fully contact and then stand to obtain an organic phase containing cobalt and an aqueous phase containing lithium and nickel;

[0017] (5) stripping the cobalt-containing organic phase obtained in step (4) to obtain the corresponding cobalt salt;

[0018] (6) adjusting the pH value of the aqueous phase containing lithium and nickel obtained in step (4), and obtaining a nickel hydroxide precipitate and a lithium-containing residual liquid after standing and solid-liquid separation;

[0019] (7) adding a saturated sodium carbonate solution to the lithium-containing residual solution obtained in step (6) for precipitation reaction, so that the lithium element is recovered in the form of lithium carbonate precipitate.

[0020] In the present invention, in step (1), the black powder is produced by using retired ternary lithium batteries with one or more positive electrode active materials containing nickel, cobalt or manganese as raw materials.

[0021] In the present invention, in step (2) and step (3), in the ammonia water-ammonium bicarbonate-hydrogen peroxide solution, the ammonia water concentration is 6.4-7.0 mol / L, the ammonium bicarbonate concentration is 0.8-1.0 mol / L, and the content of hydrogen peroxide with a mass fraction of 30% is 3 vol.%-6 vol.%.

[0022] In the present invention, in step (2) and step (3), the solid-liquid ratio of black powder to ammonia water-ammonium bicarbonate-hydrogen peroxide solution is 15:1-25:1 g / L, and the stirring rate is 300-500 rpm.

[0023] In the present invention, in step (2), the first leaching reaction time is 90 to 180 minutes; in step (3), the second leaching reaction time is 50 to 70 minutes.

[0024] In the present invention, in step (4), the pH value is 4-5, the solvent of the P507 extractant is sulfonated kerosene, the concentration of the P507 extractant is 15vol%-20vol%, and the volume ratio of the aqueous phase to the organic phase is 1:5-1:3.

[0025] In the present invention, in step (5), 1.5-3 mol / L sulfuric acid solution is used for stripping.

[0026] In the present invention, in step (6), the pH value is 9-10.

[0027] As mentioned above, the present invention preferentially removes manganese from retired ternary lithium battery black powder, uses ammonium bicarbonate and hydrogen peroxide as buffer and reductant of the ammonia system respectively, does not introduce additional cations and anions, such as sulfite ions, chloride ions and sulfate ions, and at the same time, ammonium bicarbonate acts as a buffer to prevent excessive changes in pH value from affecting the experimental environment. It has the advantages of high efficiency, low cost, short process, and environmental protection. Then, P507 is used to extract and recover cobalt, adjust the pH value to recover nickel, and finally add saturated sodium carbonate to recover lithium, which has a good prospect for industrial application. Compared with the prior art, the beneficial effects of the present invention are:

[0028] (1) The present invention provides a method for preferentially removing manganese from retired ternary lithium battery black powder and recovering key metals, using an optimized ammonia leaching method, that is, a mixed solution of ammonia water-ammonium bicarbonate-hydrogen peroxide to preferentially remove manganese and perform secondary leaching to improve the leaching rates of lithium, nickel, and cobalt. Under the optimal conditions, the leaching rate of lithium is 98.2%, and the leaching rates of nickel, cobalt, and manganese are 98.9%, 98.65%, and 1.2%, respectively.

[0029] (2) The present invention provides a method for preferentially removing manganese from retired ternary lithium battery black powder and recovering key metals. After the reaction is completed, manganese can be removed by simple filtration, reducing the difficulty and cost of subsequent separation and purification.

[0030] (3) The method provided by the present invention for preferentially removing manganese from retired ternary lithium battery black powder and recovering key metals can be expanded to other recycling fields of manganese-containing batteries, and is particularly suitable for the recycling of batteries with low manganese content, and has good prospects for industrial application.

[0031] (4) The ammonia leaching method of the present invention is carried out at room temperature, the reaction conditions are mild, and the leaching time is short, which can effectively save energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a process flow chart of a method proposed by the present invention for preferentially removing manganese from retired ternary lithium battery black powder and recovering key metals. DETAILED DESCRIPTION

[0033] Preferred embodiments of the present invention are given below in conjunction with the accompanying drawings to illustrate the technical solutions of the present invention in detail.

[0034] Figure 1 The process flow chart of the method for preferentially removing manganese and recovering key metals of the present invention is as follows:

[0035] (1) Dismantling retired ternary lithium batteries into battery cells, and obtaining black powder rich in lithium, nickel, cobalt and manganese through pretreatment such as discharge, crushing and sorting, with a particle size of 10-40 μm;

[0036] (2) adding ammonia water-ammonium bicarbonate and hydrogen peroxide solution to the black powder obtained in step (1), stirring at room temperature, and reacting fully;

[0037] (3) after the reaction in step (2) is completed, solid-liquid separation is performed to obtain a primary leaching filtrate containing lithium, nickel and cobalt and a filter residue containing manganese as the main component;

[0038] (4) returning the filter residue obtained in step (3) to step (2) for secondary leaching, and after the reaction is completed, the secondary leaching filtrate obtained is merged into the primary leaching filtrate through solid-liquid separation to obtain a leaching solution containing lithium, nickel and cobalt as main components and a manganese-containing filter residue;

[0039] (5) adjusting the pH value of the leaching solution containing lithium, nickel and cobalt obtained in step (4), mixing it with a certain concentration of P507 extractant solution according to a certain water / organic ratio, allowing them to fully contact and then standing to obtain an organic phase containing cobalt and an aqueous phase containing lithium and nickel;

[0040] (6) adding sulfuric acid to the organic phase obtained in step (5) for stripping to obtain cobalt sulfate;

[0041] (7) adjusting the pH value of the aqueous phase containing lithium and nickel obtained in step (5), and obtaining a nickel hydroxide precipitate and a lithium-containing residual solution after standing and filtering;

[0042] (8) adding a saturated sodium carbonate solution to the lithium-containing residual solution obtained in step (7) to recover the lithium in the form of lithium carbonate precipitation.

[0043] In step (2), the solid-to-liquid ratio of black powder to ammonia-ammonium bicarbonate-hydrogen peroxide solution is 20 g / L;

[0044] The reaction time in step (2) is 90 to 180 min;

[0045] In step (2), the concentration of ammonium bicarbonate is 0.8 mol / L to 1.0 mol / L, and the concentration of ammonia water is 6.4 to 7.0 mol / L;

[0046] In step (2), the content of hydrogen peroxide (mass fraction is 30%) is 3 vol% to 6 vol%;

[0047] The stirring rate in step (2) is 400 rpm;

[0048] The reaction time in step (4) is 60 min, and the other reaction conditions are the same as those in step (2);

[0049] In step (5), the pH value is 4.5, the P507 concentration is 15 vol.% to 20 vol.%, and the A / O is 1:5 to 1:3;

[0050] In step (6), the concentration of sulfuric acid is 2 mol / L;

[0051] The pH value in step (7) is 9.5.

[0052] Example 1

[0053] A method for preferentially removing manganese from retired ternary lithium battery black powder and recovering key metals

[0054] (1) Determination of metal content in samples

[0055] Take 0.1g of dried retired ternary lithium battery black powder sample and place it in a digestion tank, then add 6mL of concentrated hydrochloric acid, 2mL of concentrated nitric acid and 2mL of deionized water, and then place the digestion tank in a microwave digestion instrument. After digestion, the volume is fixed to 100mL and the solution is diluted 10 times and 100 times respectively. Then, the ICP-OES (iCAP7000) of ThermoFisher Scientific of the United States is used to quantitatively determine the content of metal components, and the results are shown in Table 1.

[0056] Table 1 Main components of retired ternary lithium battery black powder

[0057] element Li Ni Co Mn C Content (wt.%) 5.41 25.03 10.41 13.13 9.73

[0058] (2) Ammonia-ammonium bicarbonate-hydrogen peroxide preferentially removes manganese

[0059] Take 1g of black powder and place it in a beaker, control the solid-liquid ratio of black powder to ammonia-ammonium bicarbonate-hydrogen peroxide solution to 20g / L, wherein the ammonia concentration is 7.0mol / L, the ammonium bicarbonate concentration is 1.0mol / L, and the hydrogen peroxide (mass fraction is 30%) content is 6vol%, and then seal it. Place the beaker containing the mixed sample on an agitator and adjust the stirring rate to 400rpm to react for 180min, then filter with a vacuum filtration device to obtain a primary filtrate with lithium, nickel, and cobalt as the main components and a filter residue with manganese as the main component. Return the filter residue after the primary leaching to the ammonia-ammonium bicarbonate-hydrogen peroxide solution, keep the agitator speed at 400rpm and react for 60min, then filter with a vacuum filtration device, wash the filter residue with ultrapure water, and add the washing liquid to the secondary filtrate. Then, after the two filtrates are mixed evenly, the content of metal ions in the filtrate is measured by ICP-OES.

[0060] The leaching rates of lithium, nickel, cobalt and manganese were calculated using the following formulas.

[0061]

[0062]

[0063] Where, LE M : Leaching rate of metal M, %;

[0064] C L : The concentration of metal in the leachate (measured by ICP), g / L;

[0065] V L : volume of leachate, L;

[0066] m Z : The mass of the filter residue (weighed after drying at 105 ° C for 24 h), g;

[0067] W: mass fraction of metal in the filter residue, %;

[0068] C Z : The concentration of metals in the digestion solution (measured by ICP), g / L;

[0069] m: weight of filter residue, g.

[0070] The leaching rate of lithium in the system using ammonia water-ammonium bicarbonate-hydrogen peroxide solution as the leaching agent was 98.2%, and the leaching rates of nickel, cobalt and manganese were 98.9%, 98.65% and 1.2% respectively.

[0071] The leaching solution with lithium, nickel and cobalt as main components and the manganese-containing filter residue are then filtered out.

[0072] (3) Cobalt recovery

[0073] Sulfuric acid was added to adjust the pH of the lithium, nickel and cobalt leaching solutions to 4.5. Then, 15 mL P507 was mixed with 85 mL sulfonated kerosene to prepare an extractant solution of 15 vol.% P507 + 85 vol.% sulfonated kerosene. Finally, a certain amount of leaching solution was taken, and the extractant solution was added under the condition of A / O volume ratio = 1:3, and the extractant solution was allowed to fully contact and then stand for 30 minutes to obtain an organic phase containing cobalt and an aqueous phase containing lithium and nickel.

[0074] Under the condition of A / O=1:1, the cobalt-containing organic phase is stripped with 2 mol / L sulfuric acid, and the stripping solution obtained is evaporated and crystallized to prepare cobalt sulfate crystals.

[0075] (4) Recovery of nickel and lithium

[0076] Sodium hydroxide solution was added to adjust the pH of the aqueous phase containing lithium and nickel to 9.5. After standing for 30 minutes and filtering, nickel hydroxide precipitate and lithium-containing residual solution were obtained.

[0077] Finally, a saturated sodium carbonate solution is added to the lithium-containing residual solution to obtain lithium carbonate.

[0078] Example 2

[0079] A method for preferentially removing manganese from retired ternary lithium battery black powder and recovering key metals is the same as Example 1 except that: in step (2), the concentration of ammonia water is 6.4 mol / L and the concentration of ammonium bicarbonate is 0.8 mol / L.

[0080] Example 3

[0081] A method for preferentially removing manganese from retired ternary lithium battery black powder and recovering key metals is the same as Example 1 except that: the content of hydrogen peroxide (mass fraction of 30%) in step (2) is 3 vol%.

[0082] Embodiment 4 to Embodiment 5

[0083] A method for preferentially removing manganese from retired ternary lithium battery black powder and recovering key metals is the same as Example 1 except that the reaction times in step (2) are 90 minutes and 150 minutes respectively.

[0084] The leaching rate data of lithium, nickel, cobalt and manganese in Examples 1 to 5 are summarized in Table 2.

[0085] Table 2 Leaching rates of lithium, nickel, cobalt and manganese under different embodiments

[0086]

[0087]

[0088] As shown in Table 2, ammonia-ammonium bicarbonate-hydrogen peroxide solution can preferentially remove manganese from retired ternary lithium battery black powder without introducing other impurity ions during the reaction. Then, by adjusting the pH value of the leaching solution and using solvent extraction and chemical precipitation methods to recover cobalt and nickel in turn, finally adding saturated sodium carbonate solution to the lithium-containing residual liquid to recover lithium. This solves the problems of long traditional process flow, difficulty in separating nickel, cobalt and manganese, and high cost to a certain extent, and can also be expanded to other recycling fields of manganese-containing batteries, with good prospects for industrial application.

[0089] Comparative Example 1

[0090] The method for preferentially removing manganese from retired ternary lithium battery black powder and recovering key metals in this comparative example is the same as Example 1 except that: the concentration of ammonium bicarbonate in step (2) is 0.5 mol / L, and the concentration of ammonia water is 4.9 mol / L, both of which are lower than the concentrations in the example. The leaching rate of lithium was 72.51%, the leaching rate of nickel was 65.00%, the leaching rate of cobalt was 59.99%, and the leaching rate of manganese was 2.68%. Although preferential manganese removal was achieved at this time, the leaching rates of lithium, nickel, and cobalt were relatively low.

[0091] Comparative Example 2

[0092] The method for preferentially removing manganese from retired ternary lithium battery black powder and recovering key metals in this comparative example is the same as Example 1 except that hydrogen peroxide (mass fraction of 30%) is not added in step (2). The leaching rates of lithium, nickel, cobalt and manganese were measured to be 92.12%, 92.58%, 60.54% and 4.23%. Although preferential manganese removal was achieved at this time, the leaching rate of cobalt was low.

[0093] Comparative Example 3

[0094] The method for preferentially removing manganese from retired ternary lithium battery black powder and recovering key metals in this comparative example is the same as Example 1 except that the secondary leaching in step (4) is not performed, and step (5) is performed directly after completing step (3). The leaching rates of lithium, nickel, cobalt, and manganese were measured to be 62.57%, 72.28%, 53.22%, and 4.38%. Although preferential manganese removal was achieved at this time, the leaching rates of lithium, nickel, and cobalt were relatively low.

[0095] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited by the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected, and the scope of the present invention to be protected is defined by the attached claims and their equivalents.

Claims

1. A method for preferentially removing manganese from retired ternary lithium battery black powder and recovering key metals, characterized in that: The steps include: (1) Dismantle retired ternary lithium batteries into battery cells, and obtain black powder rich in lithium, nickel, cobalt and manganese through discharge, crushing and sorting pretreatment; (2) adding an ammonia water-ammonium bicarbonate-hydrogen peroxide solution to the black powder obtained in step (1), stirring at room temperature, and performing a primary leaching; after the reaction is completed, performing solid-liquid separation to obtain a primary leaching filtrate containing lithium, nickel and cobalt and a filter residue containing metallic manganese as the main component; (3) adding the filter residue obtained in step (2) into an ammonia water-ammonium bicarbonate-hydrogen peroxide solution, stirring at room temperature, and performing secondary leaching. After the reaction is completed, solid-liquid separation is performed to obtain a secondary leaching filtrate and a manganese-containing filter residue; the secondary leaching filtrate and the primary leaching filtrate are combined to obtain a leaching solution containing lithium, nickel and cobalt; (4) adjusting the pH value of the leaching solution containing lithium, nickel and cobalt obtained in step (3), mixing it with a certain concentration of P507 extractant solution at a certain aqueous phase / organic phase ratio, allowing them to fully contact and then standing to obtain an organic phase containing cobalt and an aqueous phase containing lithium and nickel; (5) stripping the cobalt-containing organic phase obtained in step (4) to obtain the corresponding cobalt salt; (6) adjusting the pH value of the aqueous phase containing lithium and nickel obtained in step (4), and obtaining a nickel hydroxide precipitate and a lithium-containing residual liquid after standing and solid-liquid separation; (7) Adding a saturated sodium carbonate solution to the lithium-containing residual solution obtained in step (6) to carry out a precipitation reaction, so that the lithium element is recovered in the form of lithium carbonate precipitate.

2. The method for preferentially removing manganese from retired ternary lithium battery black powder and recovering key metals according to claim 1, characterized in that: In step (1), the black powder is produced by using retired ternary lithium batteries with one or more positive electrode active materials containing nickel, cobalt or manganese as raw materials.

3. The method for preferentially removing manganese from retired ternary lithium battery black powder and recovering key metals according to claim 1, characterized in that: In step (2) and step (3), in the ammonia water-ammonium bicarbonate-hydrogen peroxide solution, the ammonia water concentration is 6.4-7.0 mol / L, the ammonium bicarbonate concentration is 0.8-1.0 mol / L, and the content of hydrogen peroxide with a mass fraction of 30% is 3 vol%-6 vol%.

4. The method for preferentially removing manganese from retired ternary lithium battery black powder and recovering key metals according to claim 1, characterized in that: In step (2) and step (3), the solid-liquid ratio of black powder to ammonia water-ammonium bicarbonate-hydrogen peroxide solution is 15:1-25:1 g / L, and the stirring rate is 300-500 rpm.

5. The method for preferentially removing manganese from retired ternary lithium battery black powder and recovering key metals according to claim 1, characterized in that: In step (2), the first leaching reaction time is 90 to 180 minutes; in step (3), the second leaching reaction time is 50 to 70 minutes.

6. The method for preferentially removing manganese from retired ternary lithium battery black powder and recovering key metals according to claim 1, characterized in that: In step (4), the pH value is 4-5, the solvent of the P507 extractant is sulfonated kerosene, the concentration of the P507 extractant is 15 vol.%-20 vol.%, and the volume ratio of the aqueous phase to the organic phase is 1:5-1:

3.

7. The method for preferentially removing manganese from retired ternary lithium battery black powder and recovering key metals according to claim 1, characterized in that: In step (5), stripping is performed using a 1.5-3 mol / L sulfuric acid solution.

8. The method for preferentially removing manganese from retired ternary lithium battery black powder and recovering key metals according to claim 1, characterized in that: In step (6), the pH value is 9-10.

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