Method for comprehensively recovering lithium and cobalt from waste lithium cobalt oxide battery positive electrode material

Abstract

The invention provides a method for comprehensively recovering lithium and cobalt from a waste lithium cobalt oxide battery positive electrode material, which comprises the following steps: (1) pretreating the waste lithium cobalt oxide battery positive electrode material to obtain a lithium cobalt oxide positive electrode active material; uniformly mixing the lithium cobalt oxide positive active material with a sulfenyl compound and a carbon source to obtain a mixture; the mixture is subjected to inert atmosphere roasting, grinding, leaching and filtering in sequence, and a lithium-containing solution and sulfur-containing filter residues are obtained; (2) carrying out acid leaching impurity removal on the sulfur-containing filter residues, and filtering to obtain cobalt sulfide residues; (3) roasting the cobalt sulfide slag in an oxygen atmosphere to obtain a roasted product; and (4) the roasted product is leached and filtered, and a cobalt sulfate solution and cobaltosic oxide are obtained. According to the method, soluble sulfate and high-purity cobalt oxide can be obtained, and the method is short in process, low in cost and high in lithium selectivity.

Description

Technical Field

[0001] The invention belongs to the technical field of resource utilization of waste lithium-ion batteries, and in particular relates to a method for comprehensively recovering lithium and cobalt from positive electrode materials of waste lithium cobalt oxide batteries. Background Art

[0002] For a long time, fossil fuels have been used as the main energy source, such as coal, oil and natural gas. Such an energy structure has caused serious environmental pollution, and the resulting global warming and ecological environment deterioration have attracted more and more attention. Therefore, the development of renewable energy and new energy has become one of the most decisive influences on the future technology field and the future economic world. As a new secondary clean and renewable energy, lithium-ion batteries have the advantages of high operating voltage, light weight, and high energy density. They have been widely used in power tools, digital cameras, mobile phones, laptops and other fields, and show a strong development trend.

[0003] With the booming development of new energy vehicles and the promotion of policies and markets, a large number of lithium-ion batteries have entered the market, and the recycling and reuse of waste lithium-ion batteries has become a major challenge for the industry. As the use time increases, the capacity, discharge efficiency, safety and other performance of lithium-ion batteries will decline significantly. For lithium batteries that can no longer meet current application needs, recycling can effectively play their "residual value".

[0004] The mainstream processing technology widely used at present is to obtain active substances after pretreatment of waste lithium-ion batteries, and then acid-leach, neutralize and remove impurities, separate solid and liquid, extract, precipitate lithium, wash and dry the positive electrode active substances. It consumes a large amount of acid and alkali and the equipment needs to be acid and alkali resistant. The lithium finally has a high impurity content and a low lithium recovery rate. The subsequent processing technology is cumbersome and more alkaline solution needs to be added for neutralization to remove impurities. It is necessary to develop a method that can separate and recover.

[0005] Patent document CN202110557624.3 discloses a recycling product and recycling method for waste lithium cobalt oxide batteries. The positive electrode material is dissolved by acid leaching, and the leaching is stopped when the cobalt is dissolved by 10-40% and the cobalt dissolution reaches 88-99%. The filter cake is dried and calcined. This method will cause part of the cobalt to enter the lithium-containing leachate, and the cobalt and lithium cannot be effectively separated, which will cause loss of cobalt.

[0006] Patent document CN202110399723.3 discloses a method for recycling waste cobalt oxide lithium battery positive electrode materials, which comprises adding an auxiliary agent and roasting in a reducing atmosphere; the roasting product is water-leached, and a lithium-rich solution is obtained through solid-liquid separation, and the water-leached residue is acid-leached to obtain a transition metal solution. This method has high losses, and the lithium extraction slag needs acid leaching to dissolve, and the removal process of impurities such as aluminum and iron will also produce acid and alkali losses. Summary of the invention

[0007] The technical problem to be solved by the present invention is to overcome the shortcomings and defects mentioned in the above background technology and provide a method for comprehensively recovering lithium cobalt from waste lithium cobalt oxide battery positive electrode materials. Compared with the traditional process, the method is to mix and roast the lithium cobalt oxide positive electrode active material with a sulfur-based compound and a carbon source, and acid-leach the obtained sulfur-containing filter residue to remove impurities, and then oxidize and roast the obtained cobalt sulfide slag to obtain soluble sulfate and high-purity cobalt oxide. The method has a short process, low cost and high lithium selectivity.

[0008] In order to solve the above technical problems, the technical solution proposed by the present invention is: A method for comprehensively recovering lithium cobalt from waste lithium cobalt oxide battery positive electrode materials comprises the following steps: (1) Pre-treating waste lithium cobalt oxide battery positive electrode materials to obtain lithium cobalt oxide positive electrode active materials; uniformly mixing the lithium cobalt oxide positive electrode active materials with a sulfur-based compound and a carbon source to obtain a mixture; and sequentially performing inert atmosphere roasting, grinding, leaching, and filtering on the mixture to obtain a lithium-containing solution and a sulfur-containing filter residue; The sulfur-based compound is one or more of thiourea and mercaptan; the carbon source is one or more of carbon black, lignite, and asphalt; the mass ratio of the lithium cobalt oxide positive electrode active material to the sulfur-based compound and the carbon source is 2-4:1:0.3-0.5; (2) subjecting the sulfur-containing filter residue to acid leaching and impurity removal, and filtering to obtain cobalt sulfide slag; the acid used for the acid leaching and impurity removal is at least one of sulfuric acid and hydrochloric acid; the concentration of the acid is 0.1-0.8 mol / L; the liquid-to-solid ratio of the acid leaching and impurity removal is 8-20:1 mL / g; (3) roasting the cobalt sulfide slag in an oxygen atmosphere at a temperature of 500-850° C. to obtain a roasted product; (4) Leaching and filtering the roasted product to obtain a cobalt sulfate solution and cobalt tetroxide.

[0009] The present invention adopts a sulfur-based compound, a carbon source and a lithium cobalt oxide positive electrode active material for mixed roasting, and utilizes the generated sulfurized atmosphere such as hydrogen sulfide and carbon disulfide to replace the oxygen position in the lithium cobalt oxide with a sulfur position, destroy the layered structure of the lithium cobalt oxide material, and release the lithium confined between the transition metal layers. The cobalt element is converted into a sulfide that is insoluble in water and acid, and the lithium is converted into a soluble lithium compound to achieve the lithium-cobalt separation effect. Without the addition of the sulfur-based compound, the layered structure of the lithium cobalt oxide cannot be destroyed at low temperature, and the reaction cannot proceed; without the addition of the carbon source, the sulfur generated in the reaction cannot be fixed, resulting in excessive consumption of the sulfur-based compound and a reduced reaction rate.

[0010] Preferably, the acid leaching and impurity removal time is 1-3h, the liquid-to-solid ratio is 8-20:1mL / g, and the temperature is room temperature.

[0011] Preferably, in step (3), the heating rate of the calcination is 4-5°C / min; and the calcination time is 2-4h. If the calcination temperature is too low, the reaction cannot be carried out, and if the reaction time is too long, the energy consumption increases.

[0012] Preferably, in step (4), the leaching is carried out by stirring with pure water; the leaching time is 20-60 minutes, the liquid-to-solid ratio during the leaching is 10-12:1 mL / g, and the leaching temperature is room temperature. If the leaching time is too short, the cobalt salt cannot be completely released into the solution.

[0013] The present invention controls the oxidation degree of cobalt sulfide by controlling the temperature and reaction time of oxidation roasting, and transfers the transition metal element to the liquid phase to become a sulfate solution through water immersion. The generated transition metal oxide can also be used as a negative electrode material or a raw material for synthesizing lithium cobalt oxide, thereby realizing the comprehensive recovery of lithium and cobalt from waste lithium cobalt oxide of waste lithium ion battery.

[0014] Preferably, in step (1), the waste lithium cobalt oxide battery positive electrode material is a lithium cobalt oxide battery positive electrode sheet, and the pretreatment comprises the following steps: pyrolyzing the waste lithium cobalt oxide battery positive electrode material to separate the current collector aluminum foil from the positive electrode active material, and ball milling and sieving the separated positive electrode active material to obtain the lithium cobalt oxide positive electrode active material.

[0015] Preferably, in step (1), the calcination temperature is 400-650°C, the calcination time is 5-40min, and the calcination heating rate is 5-7°C / min. In the present invention, if the calcination temperature is too low and the reaction temperature is not reached, the lithium cobalt oxide positive electrode active material cannot be decomposed. If the calcination temperature is too high, energy consumption will increase. At the same time, if the reaction time is too short, it will lead to incomplete decomposition of sulfur-based compounds, while if the reaction time is too long, it will lead to serious agglomeration of the calcined material. In addition, the calcination atmosphere is an inert atmosphere. Roasting in this atmosphere can isolate oxygen and water. Roasting in air may generate sulfate, thereby causing cobalt loss during leaching.

[0016] Preferably, in step (1), the leaching is performed by stirring leaching with water or weak acid, the leaching time is 30-60 min, the liquid-to-solid ratio during the leaching is 10-12:1 mL / g, and the leaching temperature is room temperature.

[0017] The present invention mixes the treated active material with a certain amount of sulfur-based compound and carbon source, controls the sulfidation degree of cobalt by controlling the addition amount of the sulfur-based compound and carbon source and the reaction temperature, converts the cobalt metal oxide in the positive electrode active material into insoluble sulfide, and transfers lithium from the solid phase to the liquid phase through water or weak acid leaching.

[0018] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention can generate a single transition metal sulfide (cobalt sulfide) by mixing and roasting the lithium cobalt oxide positive electrode active material with a sulfur-based compound and a carbon source, and performing acid leaching to remove impurities and filtering the sulfur-containing filter residue, and then control the conversion of the mixture into a cobalt sulfate solution and cobalt tetroxide in different proportions by oxidative roasting and water leaching. The cobalt tetroxide generated by the present invention can still be used as a battery material such as the synthesis of lithium cobalt oxide positive electrode materials or oxide negative electrode materials.

[0019] (2) The method of the present invention for comprehensively recovering lithium and cobalt from the positive electrode material of waste lithium cobalt oxide batteries reduces costs, and the transition metal element cobalt is not lost during lithium leaching, and has a high selectivity for lithium.

[0020] (3) The method of the present invention has simple process, short process time, low raw material cost and is suitable for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 It is a process flow chart of the method of the present invention; Figure 2 is the XRD pattern of the cobalt sulfide slag in Example 3; Figure 3 is the XRD pattern of the calcined product in Example 3. DETAILED DESCRIPTION

[0023] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively and meticulously below in conjunction with the accompanying drawings and preferred embodiments of the present invention, but the protection scope of the present invention is not limited to the following specific embodiments.

[0024] Unless otherwise defined, all professional terms used below have the same meanings as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0025] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0026] Embodiment 1: A method for comprehensive recovery of lithium and cobalt from waste lithium cobalt oxide battery positive electrode materials, the process flow chart is as follows Figure 1 As shown, the specific steps are as follows: (1) The waste lithium cobalt oxide battery is placed in a 130 g / L sodium chloride solution for discharge treatment, the battery shell is disassembled, and the battery is separated into the lithium cobalt oxide battery positive electrode sheet, the lithium cobalt oxide battery negative electrode sheet, the separator, and the electrolyte; the lithium cobalt oxide battery positive electrode sheet is subjected to high-temperature pyrolysis at a temperature of 650°C for 6 hours to separate the current collector aluminum foil from the positive electrode active material, and the separated positive electrode active material is ball-milled and sieved to obtain the lithium cobalt oxide positive electrode active material.

[0027] (2) The lithium cobalt oxide positive electrode active material, thiourea and carbon black are ball-milled in a mass ratio of 2:1:0.3 to ensure that the materials are evenly mixed to obtain a mixture.

[0028] (3) The mixed material obtained in step (2) is placed in a tubular furnace and calcined in an argon atmosphere at a heating rate of 5°C / min, a calcination temperature of 550°C, and a calcination time of 20 min to obtain a calcined material.

[0029] (4) Grinding the roasted material obtained in step (3), and leaching with ultrapure water at a liquid-to-solid ratio of 10:1 mL / g at room temperature for 30 min by stirring. After leaching, filtering is performed to obtain a lithium-containing filtrate with a lithium leaching rate of 99.6% and a sulfur-containing filter residue. The lithium-containing filtrate can be heated and evaporated to prepare lithium sulfide or sodium carbonate can be added to obtain lithium carbonate.

[0030] (5) The sulfur-containing filter residue obtained in step (4) is subjected to acid leaching and impurity removal, and filtered to obtain cobalt sulfide slag. The acid leaching and impurity removal is carried out using 0.5 mol / L sulfuric acid, the liquid-solid ratio is 20:1 mL / g, the acid leaching and impurity removal time is 2 hours, the temperature is room temperature, and the cobalt sulfide slag is obtained by filtering.

[0031] (6) The cobalt sulfide slag obtained in step (5) is placed in a tubular furnace and calcined in an oxygen atmosphere at a heating rate of 5°C / min, a calcination temperature of 850°C, and a calcination time of 180 min to obtain a calcined product.

[0032] (7) The roasted product obtained in step (6) was leached with ultrapure water at room temperature for 20 minutes, with a liquid-to-solid ratio of 10:1 mL / g. After leaching, it was filtered to obtain a cobalt sulfate solution and cobalt tetraoxide, with a cobalt leaching rate of 0.3%; the purity of cobalt tetraoxide reached 99.3%, which can be used as a raw material for synthesizing lithium cobaltate; the total recovery rate of cobalt was 99.3%. In the method of this embodiment, the product after high-temperature oxidation roasting is mainly cobalt tetraoxide, and the soluble cobalt sulfate is almost completely converted into an insoluble oxide, and cobalt is almost not leached.

[0033] Embodiment 2: A method for comprehensive recovery of lithium and cobalt from waste lithium cobalt oxide battery positive electrode materials, the process flow chart is as follows Figure 1 As shown, the specific steps are as follows: (1) The waste lithium cobalt oxide battery is placed in a 130 g / L sodium chloride solution for discharge treatment, the battery shell is disassembled, and the battery is separated into the lithium cobalt oxide battery positive electrode sheet, the lithium cobalt oxide battery negative electrode sheet, the separator, and the electrolyte; the lithium cobalt oxide battery positive electrode sheet is subjected to high-temperature pyrolysis at a temperature of 650°C for 6 hours to separate the current collector aluminum foil from the positive electrode active material, and the separated positive electrode active material is ball-milled and sieved to obtain the lithium cobalt oxide positive electrode active material.

[0034] (2) The lithium cobalt oxide positive electrode active material, thiourea and carbon black are ball-milled in a mass ratio of 3:1:0.5 to ensure that the materials are evenly mixed to obtain a mixture.

[0035] (3) The mixed material obtained in step (2) is placed in a tubular furnace and calcined in an argon atmosphere at a heating rate of 5°C / min, a calcination temperature of 550°C, and a calcination time of 20 min to obtain a calcined material.

[0036] (4) Grinding the roasted material obtained in step (3), and leaching with ultrapure water at a liquid-to-solid ratio of 10:1 mL / g at room temperature for 30 min under stirring. After leaching, filtering is performed to obtain a lithium-containing filtrate with a lithium leaching rate of 90% and a sulfur-containing filter residue. The lithium-containing filtrate can be heated and evaporated to prepare lithium sulfide or sodium carbonate can be added to obtain lithium carbonate.

[0037] (5) The sulfur-containing filter residue obtained in step (4) is subjected to acid leaching and impurity removal, and filtered to obtain cobalt sulfide slag. The acid leaching and impurity removal is carried out using 0.1 mol / L sulfuric acid, the liquid-solid ratio is 10:1 mL / g, the acid leaching and impurity removal time is 2 hours, the temperature is room temperature, and the cobalt sulfide slag is filtered to obtain.

[0038] (6) The cobalt sulfide slag obtained in step (5) is placed in a tubular furnace and calcined in an oxygen atmosphere at a heating rate of 5°C / min, a calcination temperature of 550°C, and a calcination time of 180 min to obtain a calcined product.

[0039] (7) The roasted product obtained in step (6) is leached with ultrapure water at room temperature for 20 minutes with a liquid-to-solid ratio of 10:1 mL / g. After leaching, it is filtered to obtain a cobalt sulfate solution and cobalt tetroxide. The leaching rate of cobalt can reach 43%. The cobalt sulfate solution can be concentrated, evaporated and crystallized to obtain high-purity cobalt sulfate. The purity of cobalt tetroxide reaches 98.0%, which can be used as a raw material for synthesizing lithium cobalt oxide. The total recovery rate of cobalt is 99.2%.

[0040] Embodiment 3: A method for comprehensive recovery of lithium and cobalt from waste lithium cobalt oxide battery positive electrode materials, the process flow chart is as follows Figure 1 As shown, the specific steps are as follows: (1) Place the waste lithium cobalt oxide battery in a 130 g / L sodium chloride solution for discharge treatment, disassemble the battery shell, and separate the battery into the lithium cobalt oxide battery positive electrode sheet, the lithium cobalt oxide battery negative electrode sheet, the separator, and the electrolyte; perform high-temperature pyrolysis on the lithium cobalt oxide battery positive electrode sheet at a temperature of 650°C for 3 h to separate the current collector aluminum foil from the positive electrode active material, and then ball-mill and sieve the separated positive electrode active material to obtain the lithium cobalt oxide positive electrode active material.

[0041] (2) The lithium cobalt oxide positive electrode active material, thiourea and carbon black are ball-milled in a mass ratio of 2:1:0.3 to ensure that the materials are evenly mixed to obtain a mixture.

[0042] (3) The mixed material obtained in step (2) is placed in a tubular furnace and calcined in an argon atmosphere at a heating rate of 5°C / min, a calcination temperature of 550°C, and a calcination time of 20 min to obtain a calcined material.

[0043] (4) Grinding the roasted material obtained in step (3), and leaching with ultrapure water at a liquid-to-solid ratio of 10:1 mL / g at room temperature for 30 min under stirring. After leaching, filtering is performed to obtain a lithium-containing filtrate with a lithium leaching rate of 99.2% and a sulfur-containing filter residue. The lithium-containing filtrate can be heated and evaporated to prepare lithium sulfide or sodium carbonate can be added to obtain lithium carbonate.

[0044] (5) The sulfur-containing filter residue obtained in step (4) is subjected to acid leaching and impurity removal, and filtered to obtain cobalt sulfide slag. The acid leaching and impurity removal is carried out using 0.5 mol / L sulfuric acid, the liquid-to-solid ratio is 10:1 mL / g, the acid leaching and impurity removal time is 2 hours, the temperature is room temperature, and the cobalt sulfide slag is filtered to obtain.

[0045] (6) The cobalt sulfide slag obtained in step (5) is placed in a tubular furnace and calcined in an oxygen atmosphere at a heating rate of 5°C / min, a calcination temperature of 600°C, and a calcination time of 240 min to obtain a calcined product.

[0046] (7) The roasted product obtained in step (6) is leached with ultrapure water at room temperature for 20 minutes with a liquid-to-solid ratio of 10:1 mL / g. After the leaching is completed, it is filtered to obtain a cobalt sulfate solution and cobalt tetroxide. The leaching rate of cobalt can reach 75%. The cobalt sulfate solution can be concentrated, evaporated and crystallized to obtain high-purity cobalt sulfate; the purity of cobalt tetroxide reaches 99.1%, which can be used as a raw material for synthesizing lithium cobalt oxide; the total recovery rate of cobalt is 99.3%.

[0047] The XRD pattern of the cobalt sulfide slag in step (5) of this embodiment is shown in Figure 2. After roasting, cobalt is converted into CoS2. The XRD pattern of the roasted product in step (6) is shown in Figure 2. Figure 3 As shown, after oxidative roasting, cobalt sulfide is converted into cobalt sulfate and cobalt tetroxide.

[0048] Comparative Example 1: Different from Example 1, in step (6) of Comparative Example 1, the calcination temperature is 400°C.

[0049] The final cobalt leaching rate was 8.2%, the purity of cobalt oxide was 15.2%, and the total recovery rate of cobalt was 99.1%. The reason for the decrease in leaching rate and purity was that the oxidation roasting temperature of 400°C did not reach the reaction temperature of CoS2, resulting in incomplete reaction and failure to convert all of it into cobalt sulfate or cobalt oxide. The cobalt oxide product contained many impurities and was difficult to utilize.

[0050] Comparative Example 2: Different from Example 3, in step (5) of Comparative Example 2, 0.05 mol / L sulfuric acid is used for acid leaching and impurity removal; the liquid-to-solid ratio is 15:1.

[0051] The final cobalt leaching rate was 43%, the purity of cobalt oxide was 94.2%, and the total recovery rate of cobalt was 99.2%. The reason for the reduced purity was that the acid concentration during acid leaching was too low, resulting in incomplete impurity removal and excessive impurities entering the cobalt oxide.

[0052] Comparative Example 3: The difference from Example 3 is that step (2) is replaced by the following steps: the lithium cobalt oxide positive electrode active material and thiourea are ball-milled and mixed in a mass ratio of 2:1 to make the materials uniformly mixed to obtain a mixture.

[0053] The final cobalt leaching rate was 51%, the purity of cobalt tetroxide was 82.3%, and the total recovery rate of cobalt was 99.1%. The reason for the decrease in leaching rate and purity was that no carbon source was added, resulting in insufficient sulfidation reaction and inability to fully convert into sulfidation components.

[0054] Comparative Example 4: The difference from Example 3 is that step (2) is replaced by the following steps: the lithium cobalt oxide positive electrode active material and the carbon black are ball-milled and mixed in a mass ratio of 2:0.3 to make the materials uniformly mixed to obtain a mixture.

[0055] The final cobalt leaching rate is 0%, and the purity of cobalt oxide is 13%. Without adding sulfur-based compounds, the waste lithium cobalt oxide cannot be effectively destroyed at low temperatures. Only a small part of the lithium cobalt oxide is decomposed, and most of the products still maintain the complete structure of lithium cobalt oxide.

Claims

1. A method for comprehensive recovery of lithium and cobalt from waste lithium cobalt oxide battery positive electrode materials, characterized in that: The following steps are involved: (1) Pre-treating waste lithium cobalt oxide battery positive electrode materials to obtain lithium cobalt oxide positive electrode active materials; uniformly mixing the lithium cobalt oxide positive electrode active materials with a sulfur-based compound and a carbon source to obtain a mixture; and sequentially performing inert atmosphere roasting, grinding, leaching, and filtering on the mixture to obtain a lithium-containing solution and a sulfur-containing filter residue; The sulfur-based compound is one or more of thiourea and mercaptan; the carbon source is one or more of carbon black, lignite, and asphalt; the mass ratio of the lithium cobalt oxide positive electrode active material to the sulfur-based compound and the carbon source is 2-4:1:0.3-0.5; (2) subjecting the sulfur-containing filter residue to acid leaching and impurity removal, and filtering to obtain cobalt sulfide slag; the acid used for the acid leaching and impurity removal is at least one of sulfuric acid and hydrochloric acid; the concentration of the acid is 0.1-0.8 mol / L; the liquid-to-solid ratio of the acid leaching and impurity removal is 8-20:1 mL / g; (3) roasting the cobalt sulfide slag in an oxygen atmosphere at a temperature of 500-850° C. to obtain a roasted product; (4) Leaching and filtering the roasted product to obtain a cobalt sulfate solution and cobalt tetroxide.

2. The method according to claim 1, characterized in that The acid leaching and impurity removal time is 1-3 hours, and the temperature is room temperature.

3. The method according to claim 1, characterized in that In step (3), the heating rate of the calcination is 4-5°C / min; and the calcination time is 2-4h.

4. The method according to claim 1, characterized in that: In step (4), the leaching is performed by stirring leaching with pure water; the leaching time is 20-60 min, the liquid-to-solid ratio during the leaching is 10-12:1 mL / g, and the leaching temperature is room temperature.

5. The method according to any one of claims 1 to 4, characterized in that In step (1), the waste lithium cobalt oxide battery positive electrode material is a lithium cobalt oxide battery positive electrode sheet, and the pretreatment comprises the following steps: pyrolyzing the waste lithium cobalt oxide battery positive electrode material to separate the current collector aluminum foil from the positive electrode active material, and ball milling and sieving the separated positive electrode active material to obtain the lithium cobalt oxide positive electrode active material.

6. The method according to any one of claims 1 to 4, characterized in that In step (1), the calcination temperature is 400-650°C, the calcination time is 5-40 min, and the calcination heating rate is 5-7°C / min.

7. The method according to any one of claims 1 to 4, characterized in that In step (1), the leaching is performed by stirring leaching with water or weak acid, the leaching time is 30-60 minutes, the liquid-to-solid ratio during the leaching is 10-12:1 mL / g, and the leaching temperature is room temperature.

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