Method for regenerating lithium iron phosphate cathode material waste

Abstract

The application discloses a kind of lithium iron phosphate anode material waste regeneration method, comprising the following steps: S1.dismantling is crushed, then calcination is carried out under inert gas, and pretreatment powder is obtained;S2.pretreatment powder is placed into leaching tank, and organic acid and ATMP compound leaching agent are added, and stirring reaction is carried out;S3.leaching liquid is cooled to room temperature, and lithium hydroxide is added to adjust pH, and after stirring, it is placed, and filter residue and filtrate are obtained by filtering;S4.anhydrous sodium carbonate is added to filtrate, and after stirring reaction, lithium carbonate precipitate is obtained by filtering separation, and high-purity lithium carbonate is obtained after washing precipitate;S5.filter residue is mixed with lithium carbonate, and acetylene black is added, then placed into ball mill and added dispersing agent to carry out ball milling, and mixed powder is obtained after spray drying;S6.mixed powder is calcined under inert gas protection, and regenerated lithium iron phosphate anode material is obtained after cooling to room temperature.The method disclosed by the application has low pollution, high recovery rate, low energy consumption and excellent performance of regenerated material.

Description

Technical Field

[0001] This invention relates to the field of electronic waste resource utilization technology, and in particular to a method for regenerating lithium iron phosphate cathode material waste. Background Technology

[0002] Lithium-ion batteries, especially lithium iron phosphate batteries, are widely used in new energy vehicles and energy storage systems. However, with their gradual obsolescence, the waste and scrap from lithium iron phosphate batteries are constantly increasing. If these wastes are not effectively recycled, they will not only waste valuable resources such as lithium, iron, and phosphorus, but may also cause environmental pollution problems. Therefore, recycling and reusing lithium iron phosphate cathode material waste is not only conducive to the efficient use of resources, but also of great significance for reducing environmental burden and promoting sustainable development.

[0003] Currently, there are some technologies for recycling waste from lithium iron phosphate cathode materials, but many methods still suffer from high energy consumption, severe pollution, and high costs. For example, the most common traditional recycling technology is hydrometallurgy, which recovers and reuses lithium and iron from lithium iron phosphate. However, hydrometallurgy usually requires the use of strong acid solvents, such as sulfuric acid or hydrochloric acid, which may lead to environmental pollution and increased costs for wastewater treatment. Furthermore, the dissolution and precipitation steps in the hydrometallurgical process are relatively complex, and the recovery efficiency is greatly affected by factors such as temperature and acid concentration, which may lead to the loss of metal elements. At the same time, the process requires a large amount of chemical reagents, resulting in high energy consumption and increased production costs. In addition, the waste and secondary pollution problems generated by hydrometallurgy still need to be further addressed, which limits its large-scale application.

[0004] Therefore, there is an urgent need to develop a method for regenerating lithium iron phosphate cathode waste that is low in pollution, has a high recovery rate, low energy consumption, and produces recycled materials with excellent performance. Summary of the Invention

[0005] The purpose of this invention is to provide a method for regenerating lithium iron phosphate cathode material waste, so as to solve the problems of high energy consumption, serious pollution and high cost of the regeneration methods of lithium iron phosphate cathode material waste mentioned in the background art.

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

[0007] A method for regenerating waste lithium iron phosphate cathode material includes the following steps: S1. Crush the cathode sheets disassembled from waste lithium iron phosphate batteries to a particle size of 50-100 μm, and calcine them at 300-400℃ for 1-2 hours under inert gas protection to remove the surface binder and obtain pretreated powder; S2. Place the pretreated powder into a leaching tank, add an organic acid and ATMP composite leaching agent at a solid-liquid ratio of 1:9-11, and stir and react at 50-70℃ for 2-3 hours to obtain a leachate; S3. Cool the leachate to room temperature, add a 5% (w / w) lithium hydroxide aqueous solution to adjust the pH of the solution to 4.5-5.0, stir for 30 minutes, let stand for 1 hour, and then... S4. Add anhydrous sodium carbonate to the filtrate obtained above, stir and react at 65~75℃ for 1~2h, then filter to separate lithium carbonate precipitate, wash the precipitate with deionized water and dry to obtain high-purity lithium carbonate; S5. Mix the filter residue with the lithium carbonate obtained in step S4 at a molar ratio of 1:1.5 to obtain a mixture, add MgSO4 and acetylene black to it, then put it into a ball mill and add a dispersant to it for wet ball milling, and spray dry after ball milling to obtain mixed powder; S6. Under inert gas protection, calcine the mixed powder at 650~750℃ for 4~4.5h, cool to room temperature to obtain regenerated lithium iron phosphate cathode material.

[0008] As a preferred embodiment of the present invention, the inert gas is either nitrogen or argon.

[0009] As a preferred embodiment of the present invention, the organic acid and ATMP composite leaching agent in S2, wherein the organic acid is any one of 0.5~1.0 mol / L citric acid and oxalic acid, and the amount of ATMP added is 5~8% of the mass of the organic acid.

[0010] As a preferred embodiment of the present invention, the stirring rate in S2 is 200~300 rpm; the stirring rate in S3 is 200~300 rpm.

[0011] As a preferred embodiment of the present invention, the amount of anhydrous sodium carbonate added in step S4 is 1.5 times the mass of the filtrate; the precipitate is washed three times with deionized water, and the amount of deionized water used each time is 5 times the mass of the precipitate; the drying temperature is 120~130℃, and the drying time is 2~2.5h.

[0012] As a preferred embodiment of the present invention, the amount of MgSO4 added in S5 is 1% to 2% of the mass of the mixture, and the amount of acetylene black added is 1% to 3% of the mass of the mixture.

[0013] As a preferred embodiment of the present invention, the dispersant in S5 is anhydrous ethanol, the solid content of the mixture is controlled to be 45-50%, the ball milling speed is 300-500 rpm, and the ball milling time is 3-4 h.

[0014] As a preferred embodiment of the present invention, the inlet air temperature of the dryer in S5 is 180~200℃ and the outlet air temperature is 80~90℃.

[0015] Compared with the prior art, the beneficial effects of the present invention are:

[0016] 1. In this invention, an organic acid is used to provide a mild acidic environment, promoting the dissolution of the LiFePO4 lattice while avoiding equipment corrosion. Aminotrimethylenephosphonic acid (ATMP) reacts with Fe through its phosphonic acid groups. 3+ Formation of stable complexes, thereby inhibiting Fe 3+ The addition of organic acids significantly reduces the impurity content of the leachate, eliminating the need for additional impurity removal processes. The wastewater also meets environmental standards. Furthermore, the use of organic acids not only reduces wastewater treatment costs but also allows for recovery through vacuum distillation, minimizing reagent waste. In addition, the elimination of high-temperature and high-pressure operations significantly reduces energy consumption and production costs. The stability of ATMP and the low toxicity of the organic acids ensure the safety of the production process, reducing the risk of organic solvent leakage and substantially lowering equipment maintenance and safety management costs.

[0017] 2. In this invention, Mg is added. 2+ Co-doping modification of Mg with similar ionic radii 2+ Embedd Fe 2+ Lattice sites fill vacancies caused by lattice breakage during the regeneration process, reducing lattice distortion and increasing crystal order. This creates stable channels for lithium-ion diffusion and significantly improves electronic conductivity. Furthermore, the doped ions form stronger ionic bonds with O²⁻, reducing the lattice volume expansion rate during charge and discharge, minimizing structural collapse, and simultaneously forming a protective film on the surface to inhibit electrolyte corrosion of Fe. 2+ This significantly enhances cycle stability. The modification does not require high-temperature sintering. Through a low-temperature regeneration process, it avoids excessive grain growth, ensures uniform grain size, and significantly reduces energy consumption, thus balancing performance and economy.

[0018] 3. This invention constructs an integrated continuous process of pretreatment, leaching, separation, and regeneration, eliminating the need for intermediate material transfer, shortening the process cycle, and significantly improving efficiency compared to traditional processes. Furthermore, the pretreated and recovered binder can be reused, and the leaching agent can be recycled through distillation. The entire process generates no waste residue, achieving a resource recycling rate of over 90%. At the same time, it reduces wastewater treatment costs and energy consumption, and the overall product cost is significantly lower than that of traditional methods. It complies with the "dual carbon" policy, is ready for industrial mass production, and achieves a win-win situation for both environmental and economic benefits. Attached Figure Description

[0019] Figure 1 This is a flowchart illustrating the regeneration process of lithium iron phosphate cathode material waste according to the present invention. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] By using organic acids to provide a mild acidic environment, the dissolution of the LiFePO4 lattice is promoted, while corrosion of the equipment is avoided. Meanwhile, aminotrimethylenephosphonic acid reacts with Fe through the phosphonic acid groups in its molecule. 3+ Formation of stable complexes, thereby inhibiting Fe 3+ The addition of organic acids significantly reduces the impurity content of the leachate, eliminating the need for additional impurity removal processes. The wastewater also meets environmental standards. Furthermore, the use of organic acids not only reduces wastewater treatment costs but also allows for recovery through vacuum distillation, minimizing reagent waste. In addition, the elimination of high-temperature and high-pressure operations significantly reduces energy consumption and production costs. The stability of aminotrimethylenephosphonic acid and the low toxicity of the organic acids ensure the safety of the production process, reducing the risk of organic solvent leakage and substantially lowering equipment maintenance and safety management costs.

[0022] By adding Mg 2+ Co-doping modification of Mg with similar ionic radii 2+ Embedd Fe 3+ Lattice sites fill vacancies caused by lattice breakage during the regeneration process, reducing lattice distortion rate, improving crystal order, and creating stable channels for lithium-ion diffusion. This also significantly improves electronic conductivity. Furthermore, the doped ions interact with O... 2- The formation of stronger ionic bonds reduces the lattice volume expansion rate during charge and discharge, minimizing structural collapse. Simultaneously, a protective film forms on the surface to inhibit electrolyte corrosion of Fe. 3+ This significantly enhances cycle stability. The modification does not require high-temperature sintering. Through a low-temperature regeneration process, it avoids excessive grain growth, ensures uniform grain size, and significantly reduces energy consumption, thus balancing performance and economy.

[0023] By constructing an integrated continuous process of pretreatment, leaching, separation, and regeneration, the process cycle is shortened without the need for intermediate material transfer. The efficiency is significantly improved compared to traditional processes. Furthermore, the binder recovered from pretreatment can be reused, and the leaching agent can be recycled through distillation. No waste residue is generated throughout the process, and the resource recycling rate exceeds 90%. At the same time, wastewater treatment costs and energy consumption are reduced, and the overall product cost is significantly lower than that of traditional methods. By controlling the solid content of the mixed slurry during wet ball milling, that is, ensuring the proportion of solids in the solid-liquid mixture after the addition of dispersant, the material is further dispersed evenly during ball milling and high ball milling efficiency is guaranteed. This complies with the "dual carbon" policy, is ready for industrial mass production, and achieves a win-win situation for both environmental and economic benefits.

[0024] like Figure 1 As shown, a method for regenerating waste lithium iron phosphate cathode material includes the following steps:

[0025] S1. The positive electrode sheets dismantled from waste lithium iron phosphate batteries are crushed to a particle size of 50-100 μm, and calcined at 300-400℃ for 1-2 hours under inert gas protection to remove the surface binder, obtaining pretreated powder; S2. The pretreated powder is placed in a leaching tank, and an organic acid and ATMP composite leaching agent are added at a solid-liquid ratio of 1:9-11. The mixture is stirred and reacted at 50-70℃ for 2-3 hours to obtain a leachate; S3. The leachate is cooled to room temperature, and a 5% (w / w) lithium hydroxide aqueous solution is added to adjust the pH to 4.5-5.0. After stirring for 30 minutes, the mixture is allowed to stand for 1 hour, and then filtered to obtain filter residue and filtrate; S4. Anhydrous sodium carbonate is added to the filtrate obtained above, and the mixture is stirred at 65~75℃ for 1~2h. Then, the precipitate of lithium carbonate is obtained by filtration. The precipitate is washed with deionized water and dried to obtain high-purity lithium carbonate. S5. The filter residue is mixed with the lithium carbonate obtained in step S4 at a molar ratio of 1:1.5 to obtain a mixture. MgSO4 and acetylene black are added to the mixture, and then it is placed in a ball mill with a dispersant added for wet ball milling. After ball milling, the mixture is spray-dried to obtain a mixed powder. S6. Under inert gas protection, the mixed powder is calcined at 650~750℃ for 4~4.5h and cooled to room temperature to obtain regenerated lithium iron phosphate cathode material.

[0026] All raw materials used in this invention are commercially available.

[0027] Example 1:

[0028] A method for regenerating waste lithium iron phosphate cathode material includes the following steps:

[0029] S1. The positive electrode sheet dismantled from the waste lithium iron phosphate battery is crushed to a particle size of 100μm, and then calcined at 400℃ for 2h under nitrogen protection to remove the surface binder and obtain pretreated powder.

[0030] S2. Place the pretreated powder into a leaching tank, add organic acid and ATMP composite leaching agent at a solid-liquid ratio of 1:11, wherein the organic acid is 1.0 mol / L citric acid, and the amount of ATMP added is 8% of the mass of citric acid. Stir and react at 70°C for 3 hours, wherein the stirring rate is 300 rpm.

[0031] S3. Cool the leachate to room temperature, add 5% lithium hydroxide aqueous solution to adjust the pH of the solution to 5.0, stir at 300 rpm for 30 min, let stand for 1 h, and filter to obtain filter residue and filtrate;

[0032] S4. Add anhydrous sodium carbonate to the filtrate obtained above, wherein the amount of anhydrous sodium carbonate added is 1.5 times the mass of the filtrate, stir and react at 75°C for 2 hours, then filter to separate and obtain lithium carbonate precipitate, wash the precipitate three times with deionized water, wherein the amount of deionized water used each time is 5 times the mass of the precipitate, and then dry it at 130°C for 2.5 hours to obtain high-purity lithium carbonate;

[0033] S5. The filter residue is mixed with the lithium carbonate obtained in step S4 at a molar ratio of 1:1.5 to obtain a mixture. 2% MgSO4 and 3% acetylene black by mass of the mixture are added to the mixture. Then, the mixture is placed in a ball mill and anhydrous ethanol is added as a dispersant. The solid content of the mixture is controlled to be 50%. Wet ball milling is performed at a speed of 500 rpm for 4 hours. After ball milling, the mixture is spray-dried to obtain a mixed powder. The inlet air temperature of the dryer is 200℃ and the outlet air temperature is 90℃.

[0034] S6. Under nitrogen protection, the mixed powder was calcined at 750°C for 4.5 hours and then cooled to room temperature to obtain the regenerated lithium iron phosphate cathode material.

[0035] Example 2:

[0036] A method for regenerating waste lithium iron phosphate cathode material includes the following steps:

[0037] S1. The positive electrode sheet dismantled from the waste lithium iron phosphate battery is crushed to a particle size of 50μm, and then calcined at 300℃ for 1h under nitrogen protection to remove the surface binder and obtain pretreated powder.

[0038] S2. Place the pretreated powder into a leaching tank, add organic acid and ATMP composite leaching agent at a solid-liquid ratio of 1:9, wherein the organic acid is 0.5 mol / L citric acid, and the amount of ATMP added is 5% of the mass of citric acid. Stir and react at 50°C for 2 hours, wherein the stirring rate is 200 rpm.

[0039] S3. Cool the leachate to room temperature, add 5% lithium hydroxide aqueous solution to adjust the pH of the solution to 4.5, stir at 200 rpm for 30 min, let stand for 1 h, and filter to obtain filter residue and filtrate;

[0040] S4. Add anhydrous sodium carbonate to the filtrate obtained above, wherein the amount of anhydrous sodium carbonate added is 1.5 times the mass of the filtrate, stir and react at 65°C for 1 hour, then filter to separate and obtain lithium carbonate precipitate, wash the precipitate three times with deionized water, wherein the amount of deionized water used each time is 5 times the mass of the precipitate, and then dry it at 120°C for 2 hours to obtain high-purity lithium carbonate.

[0041] S5. The filter residue is mixed with the lithium carbonate obtained in step S4 at a molar ratio of 1:1.5 to obtain a mixture. 1% MgSO4 and 1% acetylene black by mass of the mixture are added to the mixture. Then, the mixture is placed in a ball mill and anhydrous ethanol is added as a dispersant. The solid content of the mixture is controlled to be 45%. Wet ball milling is performed at a speed of 300 rpm for 3 hours. After ball milling, the mixture is spray-dried to obtain a mixed powder. The inlet air temperature of the dryer is 180℃ and the outlet air temperature is 80℃.

[0042] S6. Under nitrogen protection, the mixed powder was calcined at 650°C for 4 hours and then cooled to room temperature to obtain the regenerated lithium iron phosphate cathode material.

[0043] Example 3:

[0044] A method for regenerating waste lithium iron phosphate cathode material includes the following steps:

[0045] S1. The positive electrode sheet dismantled from the waste lithium iron phosphate battery is crushed to a particle size of 75μm, and then calcined at 350℃ for 1.5h under nitrogen protection to remove the surface binder and obtain pretreated powder.

[0046] S2. Place the pretreated powder into a leaching tank, add organic acid and ATMP composite leaching agent at a solid-liquid ratio of 1:10, wherein the organic acid is 0.7 mol / L citric acid, and the amount of ATMP added is 6% of the mass of citric acid. Stir and react at 60°C for 2.5 h, wherein the stirring rate is 250 rpm.

[0047] S3. Cool the leachate to room temperature, add 5% lithium hydroxide aqueous solution to adjust the pH of the solution to 4.7, stir at 250 rpm for 30 min, let stand for 1 h, and filter to obtain filter residue and filtrate;

[0048] S4. Add anhydrous sodium carbonate to the filtrate obtained above, wherein the amount of anhydrous sodium carbonate added is 1.5 times the mass of the filtrate, stir and react at 70°C for 1.5 hours, then filter to separate and obtain lithium carbonate precipitate, wash the precipitate three times with deionized water, wherein the amount of deionized water used each time is 5 times the mass of the precipitate, and then dry it at 125°C for 2.3 hours to obtain high-purity lithium carbonate;

[0049] S5. The filter residue is mixed with the lithium carbonate obtained in step S4 at a molar ratio of 1:1.5 to obtain a mixture. 1.5% MgSO4 and 2% acetylene black by mass of the mixture are added to the mixture. Then, the mixture is placed in a ball mill and anhydrous ethanol is added as a dispersant. The solid content of the mixture is controlled to be 47%. Wet ball milling is performed at a speed of 400 rpm for 3.5 h. After ball milling, the mixture is spray-dried to obtain a mixed powder. The inlet air temperature of the dryer is 190℃ and the outlet air temperature is 85℃.

[0050] S6. Under nitrogen protection, the mixed powder was calcined at 700°C for 4.2 hours and then cooled to room temperature to obtain the regenerated lithium iron phosphate cathode material.

[0051] Comparative Example 1:

[0052] The difference from Example 1 is that the dopant MgSO4 is removed.

[0053] Comparative Example 2:

[0054] The difference from Example 1 is that the organic acid and ATMP composite leaching agent is replaced with sulfuric acid.

[0055] Comparative Example 3:

[0056] The difference from Example 1 is that ATMP is removed from the organic acid and ATMP composite leaching agent.

[0057] The lithium iron phosphate cathode materials prepared in Examples 1, 2, and 3, and Comparative Examples 1, 2, and 3 were mixed at room temperature and pressure according to a mass ratio of lithium iron phosphate cathode material: acetylene black: PVDF binder of 90:5:5 to form a slurry. This slurry was then uniformly coated onto a substrate with aluminum foil as the current collector to form an electrode sheet. The resulting film thickness was 30 μm, which served as the cathode. Using lithium metal as the anode, 1 mol of LiPF6 was dissolved in 1 L of a mixed solvent of EC and DEC (where the volume ratio of EC to DEC was 1:1) to form the electrolyte. The cathode and anode sheets, separator, and electrolyte were then prepared in a nitrogen-protected glove box to create a C2032 type battery.

[0058] The electrochemical performance of the prepared battery was tested. At room temperature, the C2032 battery was charged and discharged at 0.1C to measure its charge and discharge capacity. The charging cutoff voltage was 3.8V and the discharging cutoff voltage was 2.5V. The initial charge and discharge capacity was recorded, and the charge and discharge efficiency was calculated (charge and discharge efficiency (%) = discharge capacity ÷ charge capacity × 100%). The C2032 battery was also charged and discharged at 0.1C to measure its charge and discharge capacity. The charging cutoff voltage was 3.8V and the discharging cutoff voltage was 2.5V. This was repeated 100 times, and the capacity retention rate after 100 cycles was calculated. The results are shown in Table 1.

[0059] Table 1: Chemical performance tests of the examples and comparative examples

[0060]

[0061] As shown in Table 1, Examples 1, 2, and 3 all exhibit high capacity retention and charge / discharge capacity. By using this method to regenerate waste lithium iron phosphate cathode materials, the effective components in lithium iron phosphate are fully recovered, resulting in excellent electrochemical charge / discharge performance and cycle performance.

[0062] In terms of synergistic leaching, traditional strong acids are abandoned in favor of mild organic acids to provide an acidic environment, avoiding equipment corrosion and the introduction of impurities. Meanwhile, ATMP inhibits Fe through complexation. 3+ Excessive dissolution of impurity ions significantly reduces the impurity content of the leachate, laying the foundation for the subsequent preparation of high-purity FePO4·2H2O filter residue. This reduces lattice defects caused by impurities, ensuring the performance stability of the recycled material from the source. After adding MgSO4 dopant, Mg... 2+ Due to the ionic radius and Fe 2+ Similarly, Mg can be uniformly embedded in the lithium iron phosphate lattice, filling lattice vacancies easily generated in traditional regeneration processes, optimizing crystal structure integrity, reducing lattice distortion rate, providing a smoother channel for lithium-ion diffusion, thereby improving ion transport efficiency during charging and discharging, and enhancing the material's rate charge and discharge performance; at the same time, Mg 2+ It can also adjust the distribution of electron clouds in the crystal, enhance electron delocalization, improve the electronic conductivity of the material, reduce polarization during charging and discharging, and further improve the stability of charge and discharge performance. The synergistic effect of high-purity raw materials and optimized crystal structure can enhance the lattice rigidity of the material, reduce the lattice volume expansion and contraction caused by lithium ion insertion or extraction during charge and discharge cycles, suppress structural collapse, and at the same time reduce Fe 2+ Reduce oxidation probability, decrease loss of active materials, thereby significantly improving material cycle life and ensuring good capacity retention after long-term cycling, enabling recycled materials to meet the stringent electrochemical performance requirements of power batteries.

[0063] In summary, the present invention provides a low-pollution, high-recovery-rate, and low-energy-consumption method for the regeneration of lithium iron phosphate cathode material waste. The regenerated material not only possesses excellent electrochemical charge-discharge performance but also cycle performance, meeting the stringent requirements of power batteries for electrochemical performance.

[0064] The above are merely specific embodiments of the present invention, but the technical features of the present invention are not limited thereto. Any simple changes, equivalent substitutions, or modifications made based on the present invention to solve essentially the same technical problems and achieve essentially the same technical effects are all covered within the protection scope of the present invention.

Claims

1. A method for regenerating waste lithium iron phosphate cathode material, characterized in that, Includes the following steps: S1. The positive electrode sheet dismantled from the waste lithium iron phosphate battery is crushed to a particle size of 50~100μm, and then calcined at 300~400℃ for 1~2h under inert gas protection to remove the surface binder and obtain pretreated powder. S2. Place the pretreated powder into a leaching tank, add organic acid and ATMP composite leaching agent at a solid-liquid ratio of 1:9~11, stir and react at 50~70℃ for 2~3 hours to obtain leaching solution; S3. Cool the leachate to room temperature, add 5% lithium hydroxide aqueous solution to adjust the pH of the solution to 4.5~5.0, stir for 30 min, let stand for 1 h, and filter to obtain filter residue and filtrate; S4. Add anhydrous sodium carbonate to the filtrate obtained above, stir and react at 65~75℃ for 1~2h, then filter to separate lithium carbonate precipitate, wash the precipitate with deionized water and dry to obtain high-purity lithium carbonate. S5. Mix the filter residue with the lithium carbonate obtained in step S4 at a molar ratio of 1:1.5 to obtain a mixture. Add MgSO4 and acetylene black to the mixture, then place it in a ball mill and add a dispersant. Perform wet ball milling, and spray dry the mixture after ball milling to obtain a mixed powder. S6. Under inert gas protection, the mixed powder is calcined at 650~750℃ for 4~4.5h, and then cooled to room temperature to obtain regenerated lithium iron phosphate cathode material; The organic acid and ATMP composite leaching agent in S2 is wherein the organic acid is any one of 0.5~1.0 mol / L citric acid or oxalic acid, and the amount of ATMP added is 5~8% of the mass of the organic acid; The amount of MgSO4 added in S5 is 1-2% of the mass of the mixture, and the amount of acetylene black added is 1-3% of the mass of the mixture.

2. The method for regenerating waste lithium iron phosphate cathode material according to claim 1, characterized in that, The inert gas is either nitrogen or argon.

3. The method of claim 1, wherein the lithium iron phosphate cathode material waste is a lithium iron phosphate cathode material waste from a lithium ion battery. The stirring rate in S2 is 200~300 rpm; the stirring rate in S3 is 200~300 rpm.

4. The method of claim 1, wherein the lithium iron phosphate cathode material waste is a lithium iron phosphate cathode material waste from a lithium ion battery. The amount of anhydrous sodium carbonate added in S4 is 1.5 times the mass of the filtrate; the precipitate is washed three times with deionized water, and the amount of deionized water used each time is 5 times the mass of the precipitate; the drying temperature is 120~130℃, and the drying time is 2~2.5h.

5. The method of claim 1, wherein the lithium iron phosphate cathode material waste is a lithium iron phosphate cathode material waste from a lithium ion battery. The dispersant in S5 is anhydrous ethanol, the solid content is controlled at 45-50%, the ball milling speed is 300-500 rpm, and the ball milling time is 3-4 h.

6. The method of claim 1, wherein the lithium iron phosphate cathode material waste is a cathode material waste from a lithium ion battery. The inlet air temperature of the dryer in S5 is 180~200℃, and the outlet air temperature is 80~90℃.

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