Lithium battery ternary positive electrode material recovery method

Abstract

The invention discloses a lithium battery ternary positive electrode material recovery method, and relates to the technical field of lithium battery positive electrode material recovery, and the lithium battery ternary positive electrode material recovery method comprises the following steps: S1, shredding a positive plate obtained by disassembling a waste lithium battery, placing the shredded positive plate in an alkali liquid, and stripping a positive electrode active material layer from an aluminum foil current collector through a chemical reaction to obtain dealuminated positive electrode material slurry and an aluminum foil; s2, carrying out drying and high-temperature calcination on the dealuminated material, removing the organic binder and the conductive agent to obtain calcined positive electrode material powder, and grinding the calcined positive electrode material powder for later use; s3, collecting positive electrode material powder obtained after calcination through a cyclone separation device to obtain positive electrode material black powder; s4, carrying out acid leaching dissolution on the collected positive electrode material powder under specific conditions to obtain an acid leaching solution; s5, adding a precipitator into the pickle liquor to prepare a positive electrode material precursor, so as to obtain a carbonate or oxalate precursor mixture; and S6, performing high-temperature treatment on the precursor material, and regenerating to obtain the ternary positive electrode material.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium battery positive electrode material recycling, in particular to a method for recycling lithium battery ternary positive electrode materials. Background Art

[0002] Lithium battery cathode material recycling technologies refer to a range of methods and techniques designed to efficiently and environmentally friendly extract and regenerate cathode active materials from spent lithium batteries. These technologies typically include physical pretreatment, chemical treatment, thermal treatment, and electrochemical treatment to recover and reuse the valuable components of the cathode materials. The goal is to reduce reliance on virgin resources, minimize environmental pollution, and ensure that recycled materials meet the quality requirements for new battery production, thereby supporting sustainable development and the circular economy.

[0003] In the field of lithium battery positive electrode material recycling, the existing physical stripping method is difficult to completely remove aluminum foil, resulting in a large amount of aluminum elements remaining in the positive electrode material, affecting the subsequent recycling purity. In addition, most processes do not effectively remove binders and conductive carbon black. Residual organic matter consumes acid during the acid leaching process, reducing the metal dissolution efficiency. At the same time, traditional screening or gravity sedimentation methods cannot effectively grade and collect the calcined positive electrode material black powder. Fine particles are easily dissipated into the air, causing dust pollution. Summary of the Invention

[0004] In view of the above existing problems, the present invention is proposed.

[0005] Therefore, the present invention provides a method for recycling lithium battery ternary positive electrode materials to solve the problem that the existing physical stripping method is difficult to completely remove aluminum foil, resulting in a large amount of residual aluminum elements in the positive electrode material, affecting the subsequent recovery purity, and most processes do not effectively remove the binder and conductive carbon black. The residual organic matter consumes acid during the acid leaching process, reducing the metal dissolution efficiency. At the same time, traditional screening or gravity sedimentation methods cannot effectively grade and collect the calcined positive electrode material black powder, and the fine particles are easily dissipated into the air, causing dust pollution.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions: The present invention provides a method for recycling ternary positive electrode materials of lithium batteries, which comprises: S1, tearing up the positive electrode sheets obtained by disassembling the waste lithium battery and placing them in an alkaline solution, peeling the positive electrode active material layer from the aluminum foil current collector through a chemical reaction, and obtaining a dealuminated positive electrode material slurry and aluminum foil; S2, drying and calcining the dealuminated material at high temperature to remove the organic binder and the conductive agent to obtain the calcined positive electrode material powder, which is then ground for later use; S3, collecting the positive electrode material powder obtained after calcination through a cyclone separation device to obtain positive electrode material black powder; S4, dissolving the collected cathode material powder by acid leaching under specific conditions to obtain an acid leaching solution; S5. Adding a precipitant to the acid leaching solution to prepare a positive electrode material precursor to obtain a carbonate or oxalate precursor mixture; S6. The precursor material is subjected to high-temperature treatment to regenerate the ternary positive electrode material.

[0007] As a preferred embodiment of the method for recycling lithium battery ternary positive electrode materials according to the present invention, in step S1, the alkaline solution is at least one of sodium hydroxide, potassium hydroxide or lithium hydroxide, and the concentration is 1 to 5 mol / L, the reaction temperature is 20 to 80°C, and the reaction time is 10 to 60 minutes, thereby obtaining an alkaline solution containing metaaluminate and hydrogen.

[0008] As a preferred embodiment of the method for recycling ternary positive electrode materials for lithium batteries according to the present invention, the hydrogen generated by the alkaline solution during the reaction is dried and purified and then stored and utilized to obtain dry and pure hydrogen. The chemical reaction equation during the process is:

[0009] ; in, represents two aluminum atoms from the aluminum foil current collector of the positive electrode sheet, is 2 sodium hydroxide molecules, is the direction of chemical reaction, is 2 sodium aluminate molecules, is a hydrogen molecule, is an aluminum oxide molecule, For water molecules.

[0010] As a preferred embodiment of the method for recycling lithium battery ternary cathode materials according to the present invention, in step S2, the drying temperature is 80-120° C., the drying time is 2-4 hours, and a dry dealuminated material is obtained after drying; The calcination temperature is 400-500° C., the calcination time is 1-2 hours, and the calcination is carried out under air or oxygen conditions to obtain positive electrode material powder with organic matter removed.

[0011] As a preferred embodiment of the method for recycling lithium battery ternary positive electrode materials according to the present invention, in step S4, the acid used for acid leaching is hydrochloric acid, and the concentration is 2 to 10 mol / L, the acid leaching time is 1 to 5 hours, the acid leaching temperature is room temperature to 120°C, the acid leaching pressure is negative pressure to normal pressure, and an acidic solution containing metal ions is obtained.

[0012] As a preferred embodiment of the method for recycling lithium battery ternary cathode materials according to the present invention, the chlorine gas generated during the acid leaching process is recycled and utilized through a circulation system to obtain a recyclable chlorine gas resource, and the reaction mechanism is as follows: ; ; in, Represents two ternary cathode material molecules, represents 8 hydrochloric acid molecules, represents 2 lithium chloride molecules, represents a nickel chloride molecule, represents 0.4 cobalt chloride molecules, represents 0.6 manganese chloride molecules, represents a chlorine gas molecule, represents 4 water molecules, represents a chlorine gas molecule, represents water molecules, represents the hypochlorous acid molecule, Represents a hydrochloric acid molecule.

[0013] As a preferred embodiment of the method for recycling lithium battery ternary positive electrode materials according to the present invention, in step S5, the precipitant is at least one of ammonium bicarbonate, ammonium carbonate or ammonium oxalate, the amount added is 1.0-1.2 times the standard stoichiometric ratio, the reaction temperature is 40-80°C, the reaction time is 1-3 hours, and a carbonate precipitate mixture is obtained.

[0014] As a preferred embodiment of the method for recycling ternary positive electrode materials for lithium batteries according to the present invention, the chemical reaction occurring during the preparation of the positive electrode material precursor in step S5 includes: ; ； ； ; in, represents a lithium chloride molecule, represents 2 ammonium bicarbonate molecules, represents a lithium carbonate molecule, represents 2 ammonium chloride molecules, represents water molecules, represents carbon dioxide gas, represents a nickel chloride molecule, represents a nickel carbonate molecule, represents a cobalt chloride molecule, represents a cobalt carbonate molecule, represents a manganese chloride molecule, represents a manganese carbonate molecule; After the chemical reaction process, a carbonate precursor and a by-product ammonium chloride solution are obtained.

[0015] As a preferred embodiment of the method for recycling ternary positive electrode materials for lithium batteries according to the present invention, step S6 further comprises: S6.1. Pre-calcining the carbonate precursor at 300-500° C. for 1-4 hours to obtain a pre-crystallized precursor; S6.2. After grinding, calcining at 900-1200°C for 2-6 hours to obtain a positive electrode material with a complete crystal structure; S6.3. The calcination atmosphere is air or oxygen, and the heating rate is 2-5°C / min to obtain a ternary positive electrode material.

[0016] As a preferred embodiment of the method for recycling lithium battery ternary cathode materials according to the present invention, the high-temperature calcination in step S6.2 is carried out at 1000-1100° C., and the calcination time is 8-12 hours.

[0017] The beneficial effects of the present invention are as follows: through alkaline solution dealumination, high-temperature calcination to remove impurities, cyclone separation and collection, acid leaching to dissolve metals, precipitation to prepare precursors and multi-stage heat treatment regeneration, high-value closed-loop recovery of waste positive electrode materials is achieved. The synergistic effect of each step not only improves the recovery rate of valuable metals and the regeneration performance of materials, but also improves resource utilization through the recycling and utilization of hydrogen and chlorine, reduces environmental pollution, and meets the development needs of green manufacturing and circular economy. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 This is a flow chart of the method for recycling lithium battery ternary positive electrode materials in Example 1. DETAILED DESCRIPTION

[0020] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0021] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0022] Secondly, the term "one embodiment" or "embodiment" herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in various places throughout this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive of other embodiments.

[0023] Example 1, reference Figure 1 , which is the first embodiment of the present invention, provides a method for recycling ternary positive electrode materials for lithium batteries, comprising the following steps: S1, tearing up the positive electrode sheets obtained by disassembling the waste lithium battery and placing them in an alkaline solution, peeling the positive electrode active material layer from the aluminum foil current collector through a chemical reaction, and obtaining a dealuminated positive electrode material slurry and aluminum foil; Furthermore, in step S1, the alkali solution is at least one of sodium hydroxide, potassium hydroxide or lithium hydroxide, and the concentration is 1-5 mol / L, the reaction temperature is 20-80°C, and the reaction time is 10-60 minutes, to obtain an alkaline solution containing metaaluminate and hydrogen; The hydrogen generated by the alkali solution during the reaction is dried and purified and then stored and utilized to obtain dry and pure hydrogen. The chemical reaction equation during the process is:

[0024] ; in, represents two aluminum atoms from the aluminum foil current collector of the positive electrode sheet, is 2 sodium hydroxide molecules, is the direction of chemical reaction, is 2 sodium aluminate molecules, is a hydrogen molecule, is an aluminum oxide molecule, For water molecules; It should be noted that in step S1, the use of alkaline solutions such as sodium hydroxide, potassium hydroxide or lithium hydroxide for dealumination treatment can not only effectively strip the adhesion layer between the positive electrode material and the aluminum foil, but also achieve a mild and controllable chemical stripping process by controlling the reaction concentration, temperature and time. The aluminate generated during the reaction is soluble in water, which is convenient for subsequent separation and recovery; at the same time, the hydrogen generated can be stored and utilized as clean energy after drying and purification, thereby improving the comprehensive utilization rate of resources and reducing the risk of environmental pollution.

[0025] S2, drying and calcining the dealuminated material at high temperature to remove the organic binder and the conductive agent to obtain calcined positive electrode material powder, grinding it for later use; Furthermore, in step S2, the drying temperature is 80-120°C, the drying time is 2-4 hours, and a dry dealuminated material is obtained after drying; The calcination temperature is 400-500° C., the calcination time is 1-2 hours, and the calcination is carried out under air or oxygen conditions, and a positive electrode material powder with organic matter removed is obtained; It should be noted that in step S2, the residual moisture in the material is first removed by low-temperature drying to create favorable conditions for subsequent high-temperature calcination. Calcination is carried out at 400-500°C in an inert atmosphere or vacuum environment, which can effectively remove non-metallic impurities such as organic binders and conductive carbon black remaining on the surface of the positive electrode material, thereby avoiding interference with the subsequent acid leaching process. This process not only improves the purity of the material, but also retains the original crystal structure integrity of the positive electrode material, which is beneficial to improving the subsequent recovery efficiency and the performance of the recycled material.

[0026] S3, collecting the positive electrode material powder obtained after calcination through a cyclone separation device to obtain positive electrode material black powder; Furthermore, the cyclone separation device includes an inlet wind speed control system for controlling the material entry speed; Multi-stage separation structure, including primary separation unit and fine separation unit; Cone angle adjustable mechanism to optimize separation effect; Pressure monitoring system, used to monitor pressure changes during the separation process in real time; When the cyclone separation device is working: By adjusting the inlet wind speed, the material can obtain appropriate centrifugal force, and the multi-stage separation structure is used to achieve graded collection of particles of different particle sizes; Optimize separation efficiency by adjusting the cone angle and ensure stable operation of the separation process through pressure monitoring; The primary separation unit of the cyclone separation device is used to collect cathode material particles with larger particle sizes, and the fine separation unit is used to recover cathode material powder with fine particle sizes; It should be noted that the cyclone separation device used in step S3 is equipped with an inlet wind speed control system, a multi-stage separation structure, an adjustable cone angle mechanism and a pressure monitoring system, which can achieve efficient graded collection according to the particle size distribution characteristics of the material. The primary separation unit is used to capture large particles of black powder, and the fine separation unit ensures the effective recovery of fine powder, thereby improving the overall material recovery rate and reducing dust emission, ensuring the cleanliness and safety of the operating environment, and improving the consistency of the recycled materials and the subsequent processing efficiency.

[0027] S4, dissolving the collected cathode material powder by acid leaching under specific conditions to obtain an acid leaching solution; Furthermore, in step S4, the acid used for acid leaching is hydrochloric acid with a concentration of 2 to 10 mol / L, the acid leaching time is 1 to 5 hours, the acid leaching temperature is room temperature to 120° C., the acid leaching pressure is negative pressure to normal pressure, and an acidic solution containing metal ions is obtained; The chlorine gas generated during the acid leaching process is recycled through the circulation system to obtain recyclable chlorine gas resources. The reaction mechanism is as follows: ; ; in, Represents two ternary cathode material molecules, represents 8 hydrochloric acid molecules, represents 2 lithium chloride molecules, represents a nickel chloride molecule, represents 0.4 cobalt chloride molecules, represents 0.6 manganese chloride molecules, represents a chlorine gas molecule, represents 4 water molecules, represents a chlorine gas molecule, represents water molecules, represents the hypochlorous acid molecule, represents a hydrochloric acid molecule; It should be noted that the use of high-concentration hydrochloric acid for acid leaching in step S4 can achieve efficient dissolution of valuable metals such as lithium, nickel, cobalt, and manganese in the ternary positive electrode material in a relatively short period of time, forming an acid leaching solution containing metal ions. The chlorine gas generated during the acid leaching process is condensed and absorbed by the recycling system and converted into hypochlorous acid or re-participates in the reaction, thereby realizing the closed-loop utilization of the chlorine element, avoiding the emission of toxic gases, improving the process safety and environmental protection, and reducing the acid consumption cost.

[0028] S5. Adding a precipitant to the acid leaching solution to prepare a positive electrode material precursor to obtain a carbonate or oxalate precursor mixture; Furthermore, in step S5, the precipitant is at least one of ammonium bicarbonate, ammonium carbonate or ammonium oxalate, the amount added is 1.0-1.2 times the standard stoichiometric ratio, the reaction temperature is 40-80° C., the reaction time is 1-3 hours, and a carbonate precipitation mixture is obtained; In step S5, the chemical reactions occurring during the preparation of the positive electrode material precursor include: ; ； ； ; in, represents a lithium chloride molecule, represents 2 ammonium bicarbonate molecules, represents a lithium carbonate molecule, represents 2 ammonium chloride molecules, represents water molecules, represents carbon dioxide gas, represents a nickel chloride molecule, represents a nickel carbonate molecule, represents a cobalt chloride molecule, represents a cobalt carbonate molecule, represents a manganese chloride molecule, represents a manganese carbonate molecule; After the chemical reaction process, a carbonate precursor and a by-product ammonium chloride solution are obtained; It should be noted that in step S5, by precisely controlling the type of precipitant and its addition ratio, the Li + 、Ni 2+ 、Co 3+ 、Mn 4+ The metal ions are co-precipitated according to the stoichiometric ratio of the target material to form carbonate or oxalate precursors, thereby ensuring the composition uniformity and structural consistency of the recycled material. The by-product ammonium chloride generated during the reaction can be recovered by evaporation and crystallization, realizing resource reuse, reducing wastewater discharge, and improving the green sustainability of the entire process.

[0029] S6. subjecting the precursor material to high-temperature treatment to regenerate a ternary cathode material; Furthermore, S6.1, pre-calcining the carbonate precursor at 300-500° C. for 1-4 hours to obtain a preliminarily crystallized precursor; S6.2. After grinding, calcining at 900-1200°C for 2-6 hours to obtain a positive electrode material with a complete crystal structure; S6.3. Calcination in air or oxygen atmosphere at a heating rate of 2-5°C / min to obtain a ternary cathode material; In step S6.2, the high-temperature calcination is performed at 1000-1100° C. and the calcination time is 8-12 hours; It should be noted that in step S6, a staged heat treatment method is used, first pre-calcining is carried out at a lower temperature to remove volatile substances in the precursor and initially crystallize it, and then it is fully calcined in air or oxygen atmosphere at a high temperature to enable the material to complete lattice reconstruction and form a ternary positive electrode material with excellent electrochemical properties. Controlling the heating rate helps to avoid material cracking or structural damage caused by thermal stress, and finally a regenerated positive electrode material with complete crystal form and excellent performance is obtained, which meets the high quality requirements of battery materials.

[0030] In summary, the present invention realizes high-value closed-loop recovery of waste positive electrode materials through alkaline solution dealumination, high-temperature calcination to remove impurities, cyclone separation and collection, acid leaching to dissolve metals, precipitation to prepare precursors and multi-stage heat treatment regeneration. The synergistic effect of each step not only improves the recovery rate of valuable metals and the regeneration performance of materials, but also improves resource utilization through the recycling and utilization of hydrogen and chlorine, reduces environmental pollution, and meets the development needs of green manufacturing and circular economy.

[0031] Example 2, referring to Table 1, is the second embodiment of the present invention. In order to further verify the technical solution of the present invention, experimental simulation data of the lithium battery ternary positive electrode material recycling method are provided.

[0032] This example selected five sets of used NCM523 ternary lithium battery positive plates as experimental materials, and conducted comparative tests using the traditional acid leaching method (control groups AC) and the method of the present invention (experimental groups DE). All samples were first mechanically disassembled to obtain the positive plates, and then processed according to the following process: In the alkaline solution dealumination step, the experimental group used a 3 mol / L lithium hydroxide solution and reacted at 60°C for 30 minutes. The reaction vessel was equipped with a hydrogen recovery device. Compared with the mechanical stripping method used in the control group, the experimental group achieved complete separation of the aluminum foil and significantly reduced the loss rate of the positive electrode material. ICP-MS detection showed that the residual aluminum content in the experimental group was controlled below 0.3%.

[0033] During the calcination process, the experimental group adopted a two-stage temperature control: first drying at 100°C for 3 hours, and then calcining at 450°C in an air atmosphere for 1.5 hours. Thermogravimetric analysis showed that this condition could remove 98.7% of the PVDF binder and conductive carbon black.

[0034] The cyclone separation system adopts a two-stage design, with the first-stage separator cone angle of 25° and the second-stage cone angle of 20°. The inlet wind speed is controlled at 18m / s. Laser particle size analysis shows that the D50 of the black powder collected in the experimental group is 15μm, and the particle size distribution (1-45μm) is significantly better than the mechanical screening effect of the control group.

[0035] The acid leaching process used 6 mol / L hydrochloric acid at 80°C and -0.05 MPa for 3 hours, and was equipped with a chlorine absorption circulation system. Atomic absorption spectrometry was used to determine the metal leaching rate. The results showed that the leaching rates of Li, Ni, Co, and Mn in the experimental group reached 99.2%, 98.7%, 98.5%, and 98.3%, respectively, which were approximately 8% to 12% higher than those in the control group.

[0036] During the precipitation stage, the pH was controlled at 8.5, 1.05 times the stoichiometric amount of ammonium bicarbonate was added, and the reaction was carried out at 60°C for 2 hours. XRD analysis confirmed that the obtained precursor was a pure-phase carbonate, and the relative standard deviation of the distribution uniformity of Ni, Co, and Mn (as shown by EDX mapping) was <3%.

[0037] High-temperature regeneration uses gradient calcination: first, the temperature is raised to 400°C at 3°C / min and pre-calcined for 3 hours. After grinding, the temperature is raised to 1050°C at 4°C / min and calcined for 2.5 hours. Electrochemical tests show that the first discharge specific capacity of the recycled material reaches 158.4mAh / g (0.1C), which is comparable to commercial NCM523 material (162.3mAh / g).

[0038] The details are shown in Table 1 below:

[0039] Table 1: Performance comparison data table Data Analysis and Conclusions It can be seen from the experimental data that the method of the present invention shows significant advantages in many aspects. In terms of material purity, through the optimized alkaline solution dealumination process, the residual aluminum content is reduced to 0.2%, which is much lower than the 0.9% to 2.8% of the traditional method. Thanks to the selective dissolution effect of lithium hydroxide, the complete peeling of the aluminum foil is achieved under mild conditions, while avoiding the loss of active substances caused by mechanical peeling.

[0040] Data from the calcination process showed that gradient calcination under an inert atmosphere achieved an organic matter removal rate of 99.1%, an increase of 6 to 14 percentage points over traditional methods. More importantly, this condition effectively prevented metal oxidation, creating favorable conditions for subsequent acid leaching. The grading efficiency of the cyclone separation system enabled a powder collection rate of 97.5%, and a more uniform particle size distribution, which was crucial to ensuring the uniformity of subsequent reactions.

[0041] The breakthrough in the acid leaching process is reflected in multiple dimensions: first, the negative pressure condition reduces the reaction temperature by 20°C while increasing the metal leaching rate to 99.0%; second, the chlorine circulation system increases the medium utilization rate to 94.8%, an increase of nearly 30% compared with conventional methods, greatly reducing the cost of waste acid treatment. The improvement has reduced the total energy consumption of the process to 11.5kWh / kg, with a significant energy-saving effect.

[0042] The carbonate precursor obtained in the precipitation process has excellent component uniformity, with an element distribution deviation of <3%, which lays the foundation for the structural stability of the recycled material. The high-temperature calcination process is precisely controlled by the temperature rising program, so that the recycled material obtains a discharge specific capacity of 158.4mAh / g, which is close to the level of commercial new materials. The cycle performance test shows that the capacity retention rate reaches 92.3% after 100 cycles.

[0043] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for recycling ternary cathode materials for lithium batteries, characterized by: include: S1, tearing up the positive electrode sheets obtained by disassembling the waste lithium battery and placing them in an alkaline solution, peeling the positive electrode active material layer from the aluminum foil current collector through a chemical reaction, and obtaining a dealuminated positive electrode material slurry and aluminum foil; S2, drying and calcining the dealuminated material at high temperature to remove the organic binder and the conductive agent to obtain the calcined positive electrode material powder, which is ground and set aside; S3, collecting the positive electrode material powder obtained after calcination through a cyclone separation device to obtain positive electrode material black powder; S4, dissolving the collected cathode material powder by acid leaching under specific conditions to obtain an acid leaching solution; S5. Adding a precipitant to the acid leaching solution to prepare a positive electrode material precursor to obtain a carbonate or oxalate precursor mixture; S6. The precursor material is subjected to high-temperature treatment to regenerate the ternary positive electrode material.

2. The method for recycling lithium battery ternary cathode materials according to claim 1, wherein: In step S1, the alkaline solution is at least one of sodium hydroxide, potassium hydroxide or lithium hydroxide, and the concentration is 1-5 mol / L, the reaction temperature is 20-80° C., and the reaction time is 10-60 minutes, to obtain an alkaline solution containing metaaluminate and hydrogen.

3. The method for recycling lithium battery ternary cathode materials according to claim 2, wherein: The hydrogen generated by the alkali solution during the reaction is dried and purified and then stored and utilized to obtain dry and pure hydrogen. The chemical reaction equation during the process is:

4. ； in, represents two aluminum atoms from the aluminum foil current collector of the positive electrode sheet, is 2 sodium hydroxide molecules, is the direction of the chemical reaction, is 2 sodium aluminate molecules, is a hydrogen molecule, is an aluminum oxide molecule, For water molecules.

5. The method for recycling lithium battery ternary cathode materials according to claim 3, wherein: In step S2, the drying temperature is 80-120° C., the drying time is 2-4 hours, and a dry dealuminated material is obtained after drying; The calcination temperature is 400-500° C., the calcination time is 1-2 hours, and the calcination is carried out under air or oxygen conditions to obtain positive electrode material powder with organic matter removed.

6. The method for recycling lithium battery ternary cathode materials according to claim 4, characterized in that: In step S4, the acid used for acid leaching is hydrochloric acid with a concentration of 2 to 10 mol / L, the acid leaching time is 1 to 5 hours, the acid leaching temperature is room temperature to 120° C., the acid leaching pressure is negative pressure to normal pressure, and an acidic solution containing metal ions is obtained.

7. The method for recycling lithium battery ternary cathode materials according to claim 5, characterized in that: The chlorine gas generated during the acid leaching process is recycled through a circulation system to obtain a recyclable chlorine gas resource. The reaction mechanism is as follows: ； ； in, Represents two ternary cathode material molecules, represents 8 hydrochloric acid molecules, represents 2 lithium chloride molecules, represents a nickel chloride molecule, represents 0.4 cobalt chloride molecules, represents 0.6 manganese chloride molecules, represents a chlorine gas molecule, represents 4 water molecules; represents a chlorine gas molecule, represents water molecules, represents the hypochlorous acid molecule, Represents a hydrochloric acid molecule.

8. The method for recycling lithium battery ternary cathode materials according to claim 6, wherein: In step S5, the precipitant is at least one of ammonium bicarbonate, ammonium carbonate or ammonium oxalate, the added amount is 1.0-1.2 times the standard stoichiometric ratio, the reaction temperature is 40-80° C., the reaction time is 1-3 hours, and a carbonate precipitation mixture is obtained.

9. The method for recycling lithium battery ternary cathode materials according to claim 7, wherein: In step S5, the chemical reactions occurring during the preparation of the positive electrode material precursor include: ； ； ； ； in, represents a lithium chloride molecule, represents 2 ammonium bicarbonate molecules, represents a lithium carbonate molecule, represents 2 ammonium chloride molecules, represents water molecules, represents carbon dioxide gas, represents a nickel chloride molecule, represents a nickel carbonate molecule, represents a cobalt chloride molecule, represents a cobalt carbonate molecule, represents a manganese chloride molecule, represents a manganese carbonate molecule; After the chemical reaction process, a carbonate precursor and a by-product ammonium chloride solution are obtained.

10. The method for recycling lithium battery ternary cathode materials according to claim 8, wherein: The step S6 further includes: S6.

1. Pre-calcining the carbonate precursor at 300-500° C. for 1-4 hours to obtain a pre-crystallized precursor; S6.

2. After grinding, calcining at 900-1200°C for 2-6 hours to obtain a positive electrode material with a complete crystal structure; S6.

3. The calcination atmosphere is air or oxygen, and the heating rate is 2-5°C / min to obtain a ternary positive electrode material.

11. The method for recycling lithium battery ternary cathode materials according to claim 9, wherein: In step S6.2, the high-temperature calcination is performed at 1000-1100° C., and the calcination time is 8-12 hours.

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