Degraded ternary lithium battery positive electrode material extraction process

Abstract

The application provides a degradation ternary lithium battery positive electrode material extraction process, first, in the leaching process, citric acid is used in combination with microwave radiation heating to improve the leaching reaction efficiency, then in the precipitation reaction link, a selective chelating agent is used to carry out chelation reaction separation on nickel and cobalt elements, the whole reaction path is simple, does not need to pass through an extraction step, the use of a large amount of solvent is avoided, the environment is friendly, and the separation efficiency is high.

Description

Technical Field

[0001] This invention belongs to the field of lithium-ion battery recycling technology, specifically relating to an extraction process from degraded ternary lithium battery cathode materials. Background Technology

[0002] As the production of lithium-ion batteries increases and products flood the market, a significant technical problem arises: the need to recycle large quantities of used lithium-ion batteries. The composition and structure of lithium-ion batteries are complex, containing a large amount of valuable metals, typically 5–20% cobalt, 5–20% nickel, 5–7% lithium, 5–10% other metals (such as copper, aluminum, and iron), 15% organic compounds, and 7% plastics.

[0003] There are two main technical routes for the recycling and regeneration of ternary cathode materials: The first is physical repair and regeneration. For ternary cathode materials that have only lost active lithium, a lithium source is directly added, and in-situ reverse lithium replenishment and regeneration are performed through high-temperature sintering. For cathode materials with severe capacity decay and altered surface crystal structure, hydrothermal treatment and brief high-temperature sintering regeneration are used. The second is metallurgical recycling, mainly including pyrometallurgical, hydrometallurgical, and bioleaching methods. Pyrometallurgical processes are relatively simple but energy-intensive and generate a large amount of waste gas. Hydrometallurgical processes are the most researched and applied, with core technologies including pretreatment, leaching, extraction separation, and co-precipitation preparation. Acid leaching typically uses acid to convert metals into corresponding metal ions, which are then transferred to the leachate. Acids usually include inorganic acids, organic acids, or mixtures of organic and inorganic acids. Acid leaching has the advantages of high recycling efficiency, low reaction energy consumption, and fast reaction speed, and has been widely used in the recycling of ternary lithium-ion batteries.

[0004] However, the metal ions obtained after wet leaching still require extraction and precipitation separation to obtain the final metal salt powder. This process is challenging, requiring repeated multi-stage extraction of the raffinate to ensure that the recovered metal salt reaches battery-grade purity. Furthermore, the long and complex process leads to high costs and affects yield. Therefore, based on wet recovery, there is an urgent need to explore a new extraction and separation pathway that can solve the technical problems of incomplete separation of metal elements, high separation difficulty, complex steps, and large consumption of extract in existing technologies. Summary of the Invention

[0005] Based on this, the present invention provides an extraction process for degraded ternary lithium battery cathode materials, which solves the technical problems of complex procedures, incomplete separation, and large consumption of extraction liquid in the extraction of degraded ternary lithium battery cathode materials in the prior art, and can ultimately provide metal salts with battery-grade purity.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] According to one aspect of the present invention, a process for extracting degraded ternary lithium battery cathode material is provided, comprising the following steps:

[0008] S1: Grade the degraded ternary lithium battery to obtain lithium nickel cobalt manganese oxide cathode material for later use;

[0009] S2: The lithium nickel cobalt manganese oxide cathode material obtained in S1 is placed in a citric acid solution and leached by microwave radiation under stirring. The first leachate and the first lithium-containing residue are obtained by filtration.

[0010] S3: The first lithium-containing residue from S2 is placed back into the citric acid solution and leached by microwave radiation under stirring. The second leachate and the final lithium-containing residue are obtained by filtration.

[0011] S4: After mixing the first and second leachates, add alkali to adjust the pH to 3.0-5.0, and filter to obtain Al(OH)3 precipitate;

[0012] S5: Add alkali to the filtrate from S4 to adjust the pH to 8.0-10.0, and filter to obtain Mn(OH)2 precipitate;

[0013] S6: Add a nickel ion precipitating chelating agent to the filtrate in S5, stir mechanically for 30-60 minutes, let stand for 30-60 minutes to precipitate, filter to remove the precipitate, and obtain nickel ion chelate precipitate and cobalt-containing filtrate.

[0014] S7: Add a cobalt ion precipitating chelating agent to the cobalt-containing filtrate of S6, stir mechanically for 30-60 minutes, let stand for 30-60 minutes to precipitate, filter to remove the precipitate, and obtain cobalt ion chelate precipitate and residual liquid.

[0015] S8: Add hydrochloric acid to the nickel ion chelate precipitate in S6 and the cobalt ion chelate precipitate in S7, respectively, and let stand for 30-60 minutes to desorb. Then adjust the pH value to 11-12 and precipitate with Ni(OH)2 and Co(OH)2 respectively.

[0016] In some embodiments of the present invention, the grading process in step S1 is as follows: the degraded ternary lithium battery is immersed in a sodium chloride solution until no more bubbles are generated during immersion; the degraded ternary lithium battery is then removed, dried, and disassembled to separate the positive electrode, negative electrode, and separator; the separated positive electrode is then placed in an ultrasonic solution for low-frequency ultrasonic oscillation to separate the positive electrode material from the current collector, thereby obtaining lithium nickel cobalt manganese oxide positive electrode material.

[0017] In some embodiments of the present invention, the ultrasonic low-frequency oscillation in step S1 has an ultrasonic frequency of 30-120 kHz, an oscillation duration of 20-50 min, an oscillation temperature of 20-50 °C, and the ultrasonic solution is a dimethylformamide solution, a dimethylacetamide solution, or an N-methylpyrrolidone solution.

[0018] In some embodiments of the present invention, the microwave radiation power of step S2 is 100-1000W, and the immersion time is 1h-5h.

[0019] In some embodiments of the present invention, the concentration of citric acid solution in steps S2 and S3 is 40-60 wt%, preferably 50-60 wt%; the ratio of lithium nickel cobalt manganese oxide cathode material to citric acid solution in step S2 is 1 kg: (50-100) L; and the ratio of the first lithium-containing residue to citric acid solution in step S3 is 1 kg: (30-70) L.

[0020] In some embodiments of the present invention, the nickel ion precipitable chelating agent in step S6 is a carboxylated crown ether derivative, preferably 4'-carboxybenzo-18-crown-6, and more preferably the carboxylated crown ether derivative is loaded on the surface and pores of porous magnesium silicate to form a supported nickel ion precipitable chelating agent.

[0021] In some embodiments of the present invention, the cobalt ion precipitable chelating agent in step S7 is preferably a polymer-loaded cobalt ion precipitable chelating agent in which EDTA is linked to a glycidyl methacrylate-divinylbenzene copolymer resin.

[0022] In some embodiments of the present invention, the concentration of hydrochloric acid in step S8 is 5wt%-12wt%.

[0023] Compared with the prior art, the present invention has at least the following beneficial effects:

[0024] 1. Using citric acid in combination with microwave radiation heating can improve the leaching reaction efficiency, and metal citrates are beneficial to promoting the subsequent chelation reaction process, which is conducive to the efficient separation of various metals.

[0025] 2. Selective chelating agents are used to separate nickel and cobalt through chelation reactions. The entire reaction path is simple, does not require an extraction step, and does not have the technical problem of large consumption of extract. Furthermore, supported chelating agents are preferred, and the chelating agents can be eluted and reused multiple times. Attached Figure Description

[0026] Figure 1 This invention provides a process flow diagram for extracting degraded ternary lithium battery cathode materials. Detailed Implementation

[0027] Although the invention has been described to a certain extent, it is apparent that appropriate variations can be made to the various conditions without departing from the spirit and scope of the invention. It is understood that the invention is not limited to the described embodiments, but falls within the scope of the claims, which include equivalent substitutions for each of the elements.

[0028] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0029] According to one aspect of the present invention, a process for extracting degraded ternary lithium battery cathode material is provided, comprising the following steps:

[0030] S1: Grade the degraded ternary lithium battery to obtain lithium nickel cobalt manganese oxide cathode material for later use;

[0031] S2: The lithium nickel cobalt manganese oxide cathode material obtained in S1 is placed in a citric acid solution and leached by microwave radiation under stirring. The first leachate and lithium-containing residue are obtained by filtration.

[0032] S3: The first lithium-containing residue in S2 is placed back into the citric acid solution and leached by microwave radiation under stirring. The second leachate is then obtained by filtration.

[0033] S4: After mixing the first and second leachates, add alkali to adjust the pH to 3.0-5.0, and filter to obtain Al(OH)3 precipitate;

[0034] S5: Add alkali to the filtrate from S4 to adjust the pH to 8.0-10.0, and filter to obtain Mn(OH)2 precipitate;

[0035] S6: Add a nickel ion precipitating chelating agent to the filtrate in S5, stir mechanically for 30-60 minutes, let stand for 30-60 minutes to precipitate, filter to remove the precipitate, and obtain nickel ion chelate precipitate and cobalt-containing filtrate.

[0036] S7: Add a cobalt ion precipitating chelating agent to the cobalt-containing filtrate of S6, stir mechanically for 30-60 minutes, let stand for 30-60 minutes to precipitate, filter to remove the precipitate, and obtain cobalt ion chelate precipitate and residual liquid.

[0037] S8: Add hydrochloric acid to the nickel ion chelate precipitate in S6 and the cobalt ion chelate precipitate in S7, respectively, and let stand for 30-60 minutes to desorb. Then adjust the pH value to 11-12 and precipitate with Ni(OH)2 and Co(OH)2 respectively.

[0038] In some embodiments of the present invention, the grading process in step S1 is as follows: the degraded ternary lithium battery is immersed in a sodium chloride solution until no more bubbles are generated during immersion; the degraded ternary lithium battery is then removed, dried, and disassembled to separate the positive electrode, negative electrode, and separator; the separated positive electrode is then placed in an ultrasonic solution for low-frequency ultrasonic oscillation to separate the positive electrode material from the current collector, thereby obtaining lithium nickel cobalt manganese oxide positive electrode material.

[0039] In some embodiments of the present invention, the ultrasonic low-frequency oscillation in step S1 has an ultrasonic frequency of 30-120 kHz, an oscillation duration of 20-50 min, an oscillation temperature of 20-50 °C, and the ultrasonic solution is a dimethylformamide solution, a dimethylacetamide solution, or an N-methylpyrrolidone solution.

[0040] In some embodiments of the present invention, the microwave radiation power of step S2 is 100-1000W, and the immersion time is 1h-5h.

[0041] In some embodiments of the present invention, the concentration of citric acid solution in steps S2 and S3 is 40-60 wt%, preferably 50-60 wt%; the ratio of lithium nickel cobalt manganese oxide cathode material to citric acid solution in step S2 is 1 kg: (50-100) L; and the ratio of first lithium-containing residue to citric acid solution in step S3 is 1 kg: (30-70) L.

[0042] In some embodiments of the present invention, the nickel ion precipitable chelating agent in step S6 is a carboxylated crown ether derivative, preferably 4'-carboxybenzo-18-crown-6, and more preferably the carboxylated crown ether derivative is loaded on the surface and pores of porous magnesium silicate to form a supported nickel ion precipitable chelating agent.

[0043] In some embodiments of the present invention, the cobalt ion precipitable chelating agent in step S7 is preferably a polymer-loaded cobalt ion precipitable chelating agent in which EDTA is linked to a glycidyl methacrylate-divinylbenzene copolymer resin.

[0044] In some embodiments of the present invention, the concentration of hydrochloric acid in step S8 is 5wt%-12wt%.

[0045] Example 1:

[0046] A process for extracting degraded ternary lithium battery cathode material includes the following steps:

[0047] S1: Immerse the degraded ternary lithium battery in a 2wt% sodium chloride solution until no more bubbles are produced. Remove the degraded ternary lithium battery, dry it, and then disassemble it to separate the positive electrode, negative electrode, and separator. Place the separated positive electrode in an ultrasonic solution for low-frequency ultrasonic oscillation. The ultrasonic frequency is 50KHz, the oscillation temperature is 25℃, and the ultrasonic solution is dimethylformamide solution. After oscillation for 30 minutes, separate the positive electrode material from the current collector to obtain lithium nickel cobalt manganese oxide positive electrode material for later use.

[0048] S2: 1 kg of lithium nickel cobalt manganese oxide cathode material obtained in S1 was placed into 100 L of 50 wt% citric acid solution and leached by microwave radiation at 500 W under stirring for 2 hours. The first leachate and 0.754 kg of lithium-containing residue were obtained by filtration.

[0049] S3: The first lithium-containing residue from S2 was placed back into 50L of citric acid solution and leached by microwave radiation at 500W with stirring for 2 hours. The second leachate and the final lithium-containing residue of 0.689kg were obtained by filtration.

[0050] S4: After mixing the first and second leachates, add NaOH solution to adjust the pH to 4, and filter to obtain 53.2g of Al(OH)3 precipitate;

[0051] S5: Add NaOH solution to the filtrate from S4 to adjust the pH to 9.0, and filter to obtain 127.5g of Mn(OH)2 precipitate;

[0052] S6: Add 500g of porous magnesium silicate-supported 4'-carboxybenzo-18-crown-6 (the weight ratio of magnesium silicate to 4'-carboxybenzo-18-crown-6 is 15:1) to the filtrate in S5, stir mechanically for 30min, let stand to precipitate for 30min, filter to remove the precipitate, and obtain 612.6g of nickel ion chelate precipitate and cobalt-containing filtrate;

[0053] S7: Add 560g of EDTA grafted onto glycidyl methacrylate-divinylbenzene copolymer polymer resin (with EDTA content of 8.2wt%) to the cobalt-containing filtrate of S6, stir mechanically for 30min, let stand to precipitate for 30min, filter to remove the precipitate, and obtain 644.3g of cobalt ion chelate precipitate and residual liquid.

[0054] S8: 5 L of 10 wt% hydrochloric acid was added to the nickel ion chelate precipitate in S6 and the cobalt ion chelate precipitate in S7, respectively, and allowed to stand for 30 min for desorption. Then, NaOH solution was added to adjust the pH to 11, yielding 174.5 g Ni(OH)₂ and 131.2 g Co(OH)₂ precipitates, respectively. 4'-Carboxybenzo-18-crown-6 grafted with porous magnesium silicate and EDTA was acid-washed with glycidyl methacrylate-divinylbenzene copolymer polymer resin, dried at room temperature, and recovered for later use.

[0055] Example 2:

[0056] A process for extracting degraded ternary lithium battery cathode material includes the following steps:

[0057] S1: Immerse the degraded ternary lithium battery in a 2wt% sodium chloride solution until no more bubbles are produced. Remove the degraded ternary lithium battery, dry it, and then disassemble it to separate the positive electrode, negative electrode, and separator. Place the separated positive electrode in an ultrasonic solution for low-frequency ultrasonic oscillation. The ultrasonic frequency is 50KHz, the oscillation temperature is 25℃, and the ultrasonic solution is dimethylformamide solution. After oscillation for 30 minutes, separate the positive electrode material from the current collector to obtain lithium nickel cobalt manganese oxide positive electrode material for later use.

[0058] S2: 1 kg of lithium nickel cobalt manganese oxide cathode material obtained in S1 was placed into 100 L of 60 wt% citric acid solution and leached by microwave radiation at 800 W under stirring for 4 h. The first leachate and 0.738 kg of lithium-containing residue were obtained by filtration.

[0059] S3: The first lithium-containing residue from S2 was placed back into 60L of citric acid solution and leached by microwave radiation at 800W with stirring for 4 hours. The second leachate and the final lithium-containing residue of 0.674kg were obtained by filtration.

[0060] S4: After mixing the first and second leachates, add NaOH solution to adjust the pH to 3.0, and filter to obtain 54.8g of Al(OH)3 precipitate;

[0061] S5: Add NaOH solution to the filtrate from S4 to adjust the pH to 10.0, and filter to obtain 128.6g of Mn(OH)2 precipitate;

[0062] S6: Add 500g of porous magnesium silicate-supported 4'-carboxybenzo-18-crown-6 (the weight ratio of magnesium silicate to 4'-carboxybenzo-18-crown-6 is 15:1) to the filtrate in S5, stir mechanically for 50min, let stand to precipitate for 50min, filter to remove the precipitate, and obtain 615.5g of nickel ion chelate precipitate and cobalt-containing filtrate;

[0063] S7: Add 560g of EDTA grafted onto glycidyl methacrylate-divinylbenzene copolymer polymer resin (with EDTA content of 8.2wt%) to the cobalt-containing filtrate of S6, stir mechanically for 30min, let stand to precipitate for 30min, filter to remove the precipitate, and obtain 644.9g of cobalt ion chelate precipitate and residual liquid.

[0064] S8: 2 L of 10 wt% hydrochloric acid was added to the nickel ion chelate precipitate in S6 and the cobalt ion chelate precipitate in S7, respectively, and allowed to stand for 30 min for desorption. Then, NaOH solution was added to adjust the pH to 11, yielding 175.7 g Ni(OH)₂ and 131.8 g Co(OH)₂ precipitates, respectively. 4'-carboxybenzo-18-crown-6 grafted with porous magnesium silicate and EDTA was acid-washed with glycidyl methacrylate-divinylbenzene copolymer polymer resin, dried at room temperature, and recovered for later use.

[0065] Comparative Example 1: (Oxalic Acid Extract)

[0066] A process for extracting degraded ternary lithium battery cathode material includes the following steps:

[0067] S1: Immerse the degraded ternary lithium battery in a 2wt% sodium chloride solution until no more bubbles are produced. Remove the degraded ternary lithium battery, dry it, and then disassemble it to separate the positive electrode, negative electrode, and separator. Place the separated positive electrode in an ultrasonic solution for low-frequency ultrasonic oscillation. The ultrasonic frequency is 50KHz, the oscillation temperature is 25℃, and the ultrasonic solution is dimethylformamide solution. After oscillation for 30 minutes, separate the positive electrode material from the current collector to obtain lithium nickel cobalt manganese oxide positive electrode material for later use.

[0068] S2: 1 kg of lithium nickel cobalt manganese oxide cathode material obtained in S1 was placed in 100 L of 9 wt% oxalic acid solution and leached by microwave radiation at 500 W under stirring for 2 hours. The first leachate and 0.834 kg of lithium-containing residue were obtained by filtration.

[0069] S3: The first lithium-containing residue from S2 was placed back into 50L of oxalic acid solution and leached by microwave radiation at 500W with stirring for 2 hours. The second leachate and the final lithium-containing residue of 0.746kg were obtained by filtration.

[0070] S4: After mixing the first and second leachates, add NaOH solution to adjust the pH to 4, and filter to obtain 31.5g of Al(OH)3 precipitate;

[0071] S5: Add NaOH solution to the filtrate from S4 to adjust the pH to 9.0, and filter to obtain 83.3g of Mn(OH)2 precipitate;

[0072] S6: Add 500g of porous magnesium silicate-supported 4'-carboxybenzo-18-crown-6 (the weight ratio of magnesium silicate to 4'-carboxybenzo-18-crown-6 is 15:1) to the filtrate in S5, stir mechanically for 30min, let stand to precipitate for 30min, filter to remove the precipitate, and obtain 572.9g of nickel ion chelate precipitate and cobalt-containing filtrate;

[0073] S7: Add 560g of EDTA grafted onto glycidyl methacrylate-divinylbenzene copolymer polymer resin (where the EDTA content is 8.2wt%) to the cobalt-containing filtrate of S6, stir mechanically for 30min, let stand to precipitate for 30min, filter to remove the precipitate, and obtain 607.4g of cobalt ion chelate precipitate and residual liquid.

[0074] S8: Add 5L of 10wt% hydrochloric acid to the nickel ion chelate precipitate in S6 and the cobalt ion chelate precipitate in S7, respectively, let stand for 30min for desorption, and then add NaOH solution to adjust the pH value to 11, to obtain 114.2g Ni(OH)2 and 73.5g Co(OH)2 precipitates respectively.

[0075] Comparative Example 2: (Immersion without microwave radiation heating)

[0076] A process for extracting degraded ternary lithium battery cathode material includes the following steps:

[0077] S1: Immerse the degraded ternary lithium battery in a 2wt% sodium chloride solution until no more bubbles are produced. Remove the degraded ternary lithium battery, dry it, and then disassemble it to separate the positive electrode, negative electrode, and separator. Place the separated positive electrode in an ultrasonic solution for low-frequency ultrasonic oscillation. The ultrasonic frequency is 50KHz, the oscillation temperature is 25℃, and the ultrasonic solution is dimethylformamide solution. After oscillation for 30 minutes, separate the positive electrode material from the current collector to obtain lithium nickel cobalt manganese oxide positive electrode material for later use.

[0078] S2: 1 kg of lithium nickel cobalt manganese oxide cathode material obtained in S1 was placed in 100 L of 50 wt% citric acid solution and heated to 60 °C under stirring for 2 h for leaching. The first leachate and 0.811 kg of lithium-containing residue were obtained by filtration.

[0079] S3: The first lithium-containing residue from S2 was placed back into 50L of citric acid solution and leached by microwave radiation at 500W with stirring for 2 hours. The second leachate and the final lithium-containing residue of 0.727kg were obtained by filtration.

[0080] S4: After mixing the first and second leachates, add NaOH solution to adjust the pH to 4, and filter to obtain 34.4g of Al(OH)3 precipitate;

[0081] S5: Add NaOH solution to the filtrate from S4 to adjust the pH to 9.0, and filter to obtain 86.1g of Mn(OH)2 precipitate;

[0082] S6: Add 500g of porous magnesium silicate-supported 4'-carboxybenzo-18-crown-6 (the weight ratio of magnesium silicate to 4'-carboxybenzo-18-crown-6 is 15:1) to the filtrate in S5, stir mechanically for 30min, let stand to precipitate for 30min, filter to remove the precipitate, and obtain 580.3g of nickel ion chelate precipitate and cobalt-containing filtrate;

[0083] S7: Add 560g of EDTA grafted onto glycidyl methacrylate-divinylbenzene copolymer polymer resin (with EDTA content of 8.2wt%) to the cobalt-containing filtrate of S6, stir mechanically for 30min, let stand to precipitate for 30min, filter to remove the precipitate, and obtain 610.5g of cobalt ion chelate precipitate and residual liquid.

[0084] S8: 5 L of 10 wt% hydrochloric acid was added to the nickel ion chelate precipitate in S6 and the cobalt ion chelate precipitate in S7, respectively, and allowed to stand for 30 min for desorption. Then, NaOH solution was added to adjust the pH to 11, yielding 125.9 g Ni(OH)₂ and 79.0 g Co(OH)₂ precipitates, respectively. 4'-carboxybenzo-18-crown-6 grafted with porous magnesium silicate and EDTA was acid-washed with glycidyl methacrylate-divinylbenzene copolymer polymer resin, dried at room temperature, and recovered for later use.

[0085] Comparative Example 3: (No chelating agent, multi-stage extraction method)

[0086] A process for extracting degraded ternary lithium battery cathode material includes the following steps:

[0087] S1: Immerse the degraded ternary lithium battery in a 2wt% sodium chloride solution until no more bubbles are produced. Remove the degraded ternary lithium battery, dry it, and then disassemble it to separate the positive electrode, negative electrode, and separator. Place the separated positive electrode in an ultrasonic solution for low-frequency ultrasonic oscillation. The ultrasonic frequency is 50KHz, the oscillation temperature is 25℃, and the ultrasonic solution is dimethylformamide solution. After oscillation for 30 minutes, separate the positive electrode material from the current collector to obtain lithium nickel cobalt manganese oxide positive electrode material for later use.

[0088] S2: 1 kg of lithium nickel cobalt manganese oxide cathode material obtained in S1 was placed into 100 L of 50 wt% citric acid solution and leached by microwave radiation at 500 W under stirring for 2 hours. The first leachate and 0.757 kg of lithium-containing residue were obtained by filtration.

[0089] S3: The first lithium-containing residue from S2 was placed back into 50L of citric acid solution and leached by microwave radiation at 500W with stirring for 2 hours. The second leachate and the final lithium-containing residue of 0.693kg were obtained by filtration.

[0090] S4: After mixing the first and second leachates, add NaOH solution to adjust the pH to 4, and filter to obtain 53.5g of Al(OH)3 precipitate;

[0091] S5: Add NaOH solution to the filtrate from S4 to adjust the pH to 9.0, and filter to obtain 127.1g of Mn(OH)2 precipitate;

[0092] S6: The filtrate from S5 is neutralized with sulfuric acid, and then subjected to multi-stage extraction with an extractant of P204 / kerosene (volume ratio 7:3) to obtain a cobalt sulfate solution. Evaporation yields 209.6 g of cobalt sulfate powder.

[0093] S7: The multi-stage raffinate obtained in S6 is subjected to multi-stage extraction with saponified nickel salt / kerosene (weight ratio 7:3) extractant of P507 to obtain nickel sulfate solution, and evaporated to obtain 280.4g of nickel sulfate powder.

[0094] The recovery results based on Examples 1-2 and Comparative Examples 1-3 are shown in Table 1:

[0095] Table 1 shows the recovery amount and recovery rate of each substance in Examples 1-2 and Comparative Examples 1-3.

[0096]

[0097]

[0098] As shown in Table 1, citric acid combined with microwave irradiation heating enables rapid and efficient leaching, achieving higher leaching efficiency compared to oxalic acid or non-microwave irradiation methods. This results in higher recovery rates of nickel, cobalt, manganese, and aluminum impurities. Citric acid as the filtrate medium also enhances the chelation efficiency of nickel and cobalt, leading to higher recovery rates than existing multi-stage extraction methods. Furthermore, the chelating agent with the stationary phase can be reused after purification following elution, avoiding the waste of extractant that cannot be reused after evaporation. Therefore, the extraction process of this invention offers high recovery rates for each element, excellent separation effects, and a simple process that avoids the large-scale use of solvents, making it more environmentally friendly.

[0099] The above embodiments are merely examples of implementation methods of the invention. The scope of protection of the present invention is not limited to the above embodiments. For those skilled in the art, several modifications and improvements can be made without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention.

Claims

1. A process for extracting a degraded ternary lithium battery cathode material, characterized in that, The method comprises the following steps: S1: grading treatment of degraded ternary lithium battery to obtain nickel-cobalt-manganese lithium cathode material, standby; S2: the nickel-cobalt-manganese lithium cathode material obtained in S1 is put into a citric acid solution, and microwave radiation heating leaching is carried out under stirring to obtain a first leaching solution and a first lithium-containing residue after filtration; S3: the first lithium-containing residue in S2 is put into a citric acid solution again, and microwave radiation heating leaching is carried out under stirring to obtain a second leaching solution and a final lithium-containing residue after filtration; S4: after mixing the first leaching solution and the second leaching solution, the pH is adjusted to 3.0-5.0 by adding alkali, and Al(OH)3 precipitate is obtained after filtration; S5: the filtrate in S4 is continuously adjusted to a pH of 8.0-10.0 by adding alkali, and Mn(OH)2 precipitate is obtained after filtration; S6: a nickel ion precipitable chelating agent is added to the filtrate in S5, and after mechanical stirring for 30-60 min, the precipitate is allowed to stand for 30-60 min, and the precipitate is removed by filtration to obtain a nickel ion chelate precipitate and a cobalt-containing filtrate; S7: a cobalt ion precipitable chelating agent is added to the cobalt-containing filtrate in S6, and after mechanical stirring for 30-60 min, the precipitate is allowed to stand for 30-60 min, and the precipitate is removed by filtration to obtain a cobalt ion chelate precipitate and a residual liquid; S8: hydrochloric acid is added to the nickel ion chelate precipitate in S6 and the cobalt ion chelate precipitate in S7, respectively, and desorption is carried out after standing for 30-60 min, and then the pH is adjusted to 11-12 to precipitate Ni(OH)2 and Co(OH)2, respectively; In the step S2, the microwave radiation power is 100-1000W, and the leaching time is 1h-5h; The concentration of the citric acid solution in steps S2 and S3 is 40-60wt%; In the step S2, the ratio of the nickel-cobalt-manganese lithium cathode material to the citric acid solution is 1kg:(50-100)L; In the step S3, the ratio of the first lithium-containing residue to the citric acid solution is 1kg:(30-70)L; In the step S6, the nickel ion precipitable chelating agent is a carboxylated crown ether derivative, specifically 4'-carboxybenzo-18-crown-6, and the carboxylated crown ether derivative is loaded on the surface and pores of porous magnesium silicate to form a supported nickel ion precipitable chelating agent.

2. The process according to claim 1, characterized in that, In the step S1, the grading treatment is to soak the degraded ternary lithium battery in a sodium chloride solution until no bubbles are generated during soaking, take out the degraded ternary lithium battery, dry it, then disassemble it, separate the positive electrode sheet, negative electrode sheet, and separator, put the separated positive electrode sheet into an ultrasonic solution for ultrasonic low-frequency oscillation to separate the positive electrode material from the current collector, and obtain the nickel-cobalt-manganese lithium cathode material.

3. The process of claim 2, wherein, In the step S1, the ultrasonic low-frequency oscillation has an ultrasonic frequency of 30-120KHz, an oscillation time of 20-50min, an oscillation temperature of 20-50℃, and an ultrasonic solution of dimethylformamide solution, dimethylacetamide solution, or N-methyl pyrrolidone solution.

4. The process of claim 1, wherein, In the step S7, the cobalt ion precipitable chelating agent is specifically an EDTA connected to a glycidyl methacrylate-divinylbenzene copolymer high molecular resin polymer supported cobalt ion precipitable chelating agent.

5. The process of claim 1, wherein, The concentration of the hydrochloric acid in step S8 is 5wt%-12wt%.

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