Method for selectively recovering valuable metal from waste ternary lithium battery and synthesizing regenerated positive electrode material

Abstract

The invention discloses a method for selectively recovering valuable metals from a waste ternary lithium battery and synthesizing a regenerated positive electrode material, which comprises the following steps: (1) pretreating the waste ternary lithium battery, and separating to obtain a carbon powder material of a negative electrode and the positive electrode material; (2) mixing the positive electrode material with carbon powder, and reacting in a nitrogen atmosphere at a certain temperature; (3) adding the carbon thermal reduction product into water for leaching reaction, and then filtering to obtain carbon thermal reduction product leachate and water leaching residues; (4) evaporating and crystallizing the carbon thermal reduction product leachate to obtain Li2CO3, and oxidizing and roasting water leaching residues to obtain a ternary precursor; and (5) fully grinding and mixing Li2CO3 and the ternary precursor, and then carrying out two-step heat treatment reaction to obtain the regenerated positive electrode material. According to the method disclosed by the invention, Li remained in the waste positive electrode material is removed and relatively uniform particles are obtained through carbon thermal reduction-water leaching selective extraction, so that a homogeneous reaction in a regeneration synthesis process is promoted, and an effect of waste utilization of the negative electrode carbon powder is also achieved.

Description

Technical Field

[0001] The invention relates to the technical field of battery recycling, and in particular to a method for selectively recovering valuable metals from waste ternary lithium batteries and synthesizing regenerated positive electrode materials. Background Art

[0002] Lithium-ion batteries are widely used in storage devices such as mobile phones, laptops, and new energy vehicles due to their high energy density and long cycle life. However, the life of lithium-ion batteries is limited. Generally speaking, the life of lithium-ion batteries is usually around 3 to 5 years. If they are not properly disposed of, they will cause serious problems to the environment. On the other hand, the relative content of lithium, cobalt and other elements in waste positive electrode materials is higher than that of natural ores, and has a higher economic value. Therefore, whether from the perspective of environmental protection or economic development, recycling and utilizing the valuable metals in waste lithium batteries is of great significance.

[0003] At present, the research on the recycling methods of waste ternary positive electrode materials mainly includes wet recycling, pyrometallurgical recycling and regeneration recycling. Due to the advantages of high metal ion recovery rate, short recycling process route and considerable economic value of recycling process, the method of directly regenerating new materials using valuable metals such as Ni, Co and Mn in positive electrode materials has attracted widespread attention. However, waste positive electrode materials are prone to various types of degradation, which must be considered in the recycling process, such as intergranular cracks in secondary particles caused by the shrinkage / expansion of primary particles, uneven distribution of residual elements (especially Li) and different particle sizes. Therefore, it is of great significance to find a method that can selectively recover Li and resynthesize positive electrode materials to achieve the recycling of lithium batteries.

[0004] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention and should not be regarded as an acknowledgment or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art. Summary of the invention

[0005] The purpose of the present invention is to provide a method for selectively recovering valuable metals from waste ternary lithium batteries and synthesizing regenerated positive electrode materials, thereby overcoming the shortcomings of uneven distribution of residual elements, long recovery process, secondary pollution, etc.

[0006] To achieve the above object, the present invention provides a method for selectively recovering valuable metals from waste ternary lithium batteries and synthesizing regenerated positive electrode materials, comprising the following steps:

[0007] (1) Pre-treating the waste ternary lithium battery to separate the negative electrode carbon powder material and the positive electrode material;

[0008] (2) mixing the positive electrode material and carbon powder, reacting them in a nitrogen atmosphere at a certain temperature to obtain a carbon thermal reduction product;

[0009] (3) adding the carbon thermal reduction product into water for leaching reaction, and then filtering to obtain a carbon thermal reduction product leaching solution and water leaching residue;

[0010] (4) evaporating and crystallizing the carbon thermal reduction product leaching solution to obtain Li2CO3, and oxidizing and roasting the water leached residue to obtain a ternary precursor;

[0011] (5) Li2CO3 and the ternary precursor are fully ground and mixed, and then subjected to a two-step heat treatment reaction to obtain a regenerated positive electrode material.

[0012] Preferably, in the above technical solution, the pretreatment in step (1) includes:

[0013] 1) Discharge the waste ternary lithium battery and separate the positive electrode sheet and the negative electrode sheet;

[0014] 2) The carbon powder of the negative electrode plate is ground and sieved to obtain a carbon powder sample, and the positive electrode plate is alkali-leached, ground and sieved to obtain a positive electrode material.

[0015] Preferably, in the above technical solution, the discharging in step 1) is: placing the waste ternary lithium-ion battery in a 10-30wt% NaCl solution for discharging for 24-48h.

[0016] Preferably, in the above technical solution, step 2) alkali leaching treatment is to place in an alkaline solution with a solid-liquid ratio of 20-25 g / L, a reaction temperature of 50-70°C, and a reaction time of 30-120 min; wherein the alkali solution is a NaOH solution or a KOH solution, and the concentration of the alkali solution is 0.5-3 mol / L.

[0017] Preferably, in the above technical solution, the temperature of the mixed reaction of the positive electrode material and the carbon powder in step (2) is 550-750° C., and the reaction time is 30-180 min; the mass proportion of the carbon powder in the mixed powder is 5-25%.

[0018] Preferably, in the above technical solution, the solid-to-liquid ratio of the mixture of the carbon thermal reduction product and water in step (3) is 10-60 g / L, and the reaction is carried out at room temperature for 30-150 min; preferably, the water is ultrapure water.

[0019] Preferably, in the above technical solution, in step (4), the carbon thermal reduction product leaching solution is first boiled and then evaporated and crystallized, the evaporation and crystallization temperature is 80-95° C., and the evaporation and crystallization time is 1-10 h.

[0020] Preferably, in the above technical solution, the calcination conditions of the water-leached slag in step (4) are as follows: calcination temperature of 700-800° C. and calcination time of 60-120 min in an oxygen atmosphere.

[0021] Preferably, in the above technical solution, the molar ratio of Li2CO3 and the ternary precursor ground and mixed in step (5) is Li / Me=1.02-1.08.

[0022] Preferably, in the above technical solution, the two-step heat treatment reaction in step (5) includes: preheating at 500-600°C for 2-8h under an oxygen atmosphere and then heating to 750-950°C for 8-12h to obtain a regenerated positive electrode material.

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

[0024] (1) The method of the present invention for selectively recovering valuable metals from waste ternary lithium batteries and synthesizing regenerated positive electrode materials adopts a combined process of carbon thermal reduction-water immersion-high temperature solid phase. Carbon thermal reduction converts Li into Li2CO3 that is easily soluble in water, while other substances are converted into insoluble metal elements and metal oxides. Li2CO3 in the carbon thermal reduction product can be leached out by simple water immersion at room temperature, and other substances remain in the leached residue. As a selective extraction method, carbon thermal reduction-water immersion can remove Li remaining in waste positive electrode materials and obtain relatively uniform particles, thereby promoting homogeneous reactions in the regeneration synthesis process, and at the same time, it also has the effect of waste utilization of carbon powder on the negative electrode of lithium batteries.

[0025] (2) The method of the present invention prepares the recovered Li2CO3 and precursor into regenerated ternary materials through high-temperature solid phase, which can realize the true recycling of lithium-ion batteries. At the same time, no additional acid, alkali or other substances are added in the entire recycling and regeneration process, no waste liquid is generated, and no complicated metal separation steps are involved. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a process flow chart of the method for selectively recovering valuable metals from waste ternary lithium batteries and synthesizing regenerated positive electrode materials according to the present invention;

[0027] Figure 2 is an XRD diagram of the Li2CO3 product and the regenerated ternary material prepared according to method Example 1 of the present invention;

[0028] Figure 3 is a SEM image of the Li2CO3 product prepared according to method Example 1 of the present invention;

[0029] Figure 4 This is a SEM-EDS image of the regenerated ternary material prepared according to method example 1 of the present invention. DETAILED DESCRIPTION

[0030] The specific implementation modes of the present invention are described in detail below in conjunction with the accompanying drawings, but it should be understood that the protection scope of the present invention is not limited by the specific implementation modes.

[0031] Unless explicitly stated otherwise, throughout the specification and claims, the term “comprise” or variations such as “include” or “comprising”, etc., will be understood to include the stated elements or components but not to exclude other elements or components.

[0032] Raw material preparation

[0033] Use waste ternary lithium batteries as raw materials to pretreat waste lithium batteries. The pretreatment includes soaking the waste lithium-ion batteries in 20wt% NaCl for discharge, disassembling and removing the battery shell, and separating the positive and negative electrodes. The positive electrode is treated with alkaline leaching using NaOH solution to selectively dissolve the aluminum foil. The alkaline leaching conditions are: NaOH solution concentration 1mol / L, solid-liquid ratio 25g / L, reaction temperature 60°C, reaction time 60min, vacuum filtration after alkaline leaching and repeated washing several times, drying and manual grinding and passing through a 100-mesh standard sieve to obtain a positive electrode material experimental sample. Peel off the carbon powder on the negative electrode and grind through a 100-mesh sieve to obtain a carbon powder experimental sample.

[0034] In the positive electrode material, the Li content is 3.10wt%, the Ni content is 34.19wt%, the Co content is 13.32wt%, the Mn content is 18.28wt%, the Al content is 0.28wt%, and the Cu content is 0.09wt%.

[0035] Example 1

[0036] A method for selectively recovering valuable metals from waste ternary lithium batteries and synthesizing regenerated positive electrode materials, the process flow chart of which is as follows: Figure 1 As shown, it includes four parts: pretreatment of waste lithium-ion batteries, carbon thermal reduction roasting of positive electrode materials, selective leaching of Li from carbon thermal reduction products, and synthesis of regenerated ternary materials. Specifically, it includes the following steps:

[0037] (1) Carbothermal reduction: 4.5 g of the pretreated positive electrode material and 0.5 g of carbon powder (carbon powder accounts for 10%) were mixed evenly and placed in a corundum boat, and the corundum boat was placed in a tube furnace, and the tube furnace was heated at a rate of 10°C / min in a nitrogen atmosphere, and the calcination temperature was 650°C for 1.5 h. After cooling to room temperature, the mixture was taken out and ground through a 100-mesh sieve to obtain a carbothermal reduction product.

[0038] (2) Ultrapure water leaching: 3 g of the carbon thermal reduction product, 300 mL of ultrapure water and a stirring bar were placed in a 500 mL beaker. After stirring and leaching for 1 h at room temperature, the carbon thermal reduction product leaching solution and water leaching residue were obtained by filtration.

[0039] (3) Evaporation crystallization: Take 300 mL of the carbon thermal reduction product leaching solution and place it in a beaker. Heat and boil until about 15 mL of solution remains in the beaker. Place it in an electric constant temperature blast drying oven at 85°C and dry it for 12 hours to ensure that the liquid in the beaker is completely evaporated. Collect the Li2CO3 product.

[0040] (4) Preparation of ternary precursor: 2 g of water-leached slag was placed in an alumina crucible, the crucible was placed in a tubular furnace, and O2 was introduced for calcination at a temperature of 750 °C for 2 h.

[0041] (5) High-temperature solid phase: 2 g of the ternary precursor was mixed with Li2CO3 at a molar ratio of Li / Me = 1.05:1 for 15 min. The uniformly mixed powder was placed in a tube furnace and calcined by passing O2 at a heating rate of 10 °C / min. The material was first pre-calcined at 500 °C for 5 h, then heated to 850 °C for 10 h, manually ground and sieved through a 200-mesh sieve to obtain a regenerated positive electrode material.

[0042] (6) Testing of regenerated positive electrode materials: The regenerated positive electrode materials were prepared into CR2032 type coin cells and the charge / discharge tests were performed between 3.00-4.50V using a battery tester.

[0043] The Li leaching efficiency of this embodiment is 93.1%, the purity of Li2CO3 is 99.7%, and the initial discharge capacity of the regenerated positive electrode material at a current density of 0.1C is 134.4 mAh·g -1 , the capacity retention rate after 50 cycles is 93.4%.

[0044] Example 2

[0045] A method for selectively recovering valuable metals from waste ternary lithium batteries and synthesizing regenerated positive electrode materials, the process flow chart of which is as follows: Figure 1 As shown, it includes four parts: pretreatment of waste lithium-ion batteries, carbon thermal reduction roasting of positive electrode materials, selective leaching of Li from carbon thermal reduction products, and synthesis of regenerated ternary materials, specifically including the following steps:

[0046] (1) Carbothermal reduction: 4.5 g of the pretreated positive electrode material and 0.5 g of carbon powder (carbon powder accounts for 10%) were mixed evenly and placed in a corundum boat, which was placed in a tube furnace. The tube furnace was heated at a rate of 10°C / min in a nitrogen atmosphere, and the calcination temperature was 600°C for 1.5 h. After cooling to room temperature, the mixture was taken out and ground through a 100-mesh sieve to obtain a carbothermal reduction product.

[0047] (2) Ultrapure water leaching: 3 g of the carbon thermal reduction product, 300 mL of ultrapure water and a stirring bar were placed in a 500 mL beaker. After stirring and leaching for 1 h at room temperature, the carbon thermal reduction product leaching solution and water leaching residue were obtained by filtration.

[0048] (3) Evaporation crystallization: Take 300 mL of the carbon thermal reduction product leaching solution and place it in a beaker. Heat and boil until about 15 mL of solution remains in the beaker. Place it in an electric constant temperature blast drying oven at 85°C and dry it for 12 hours to ensure that the liquid in the beaker is completely evaporated. Collect the Li2CO3 product.

[0049] (4) Preparation of ternary precursor: 2 g of water-leached slag was placed in an alumina crucible, the crucible was placed in a tubular furnace, and O2 was introduced for calcination at a temperature of 750 °C for 2 h.

[0050] (5) High-temperature solid phase: 2 g of the ternary precursor was mixed with Li2CO3 at a molar ratio of Li / Me = 1.05:1 for 15 min. The uniformly mixed powder was placed in a tube furnace and calcined by passing O2 at a heating rate of 10 °C / min. The material was first pre-calcined at 500 °C for 5 h, then heated to 850 °C for 10 h, manually ground and sieved through a 200-mesh sieve to obtain a regenerated positive electrode material.

[0051] (6) Testing of regenerated positive electrode materials: The regenerated positive electrode materials were prepared into CR2032 type coin cells and the charge / discharge tests were performed between 3.00-4.50V using a battery tester.

[0052] The Li leaching efficiency of this embodiment is 83.7%, the purity of Li2CO3 is 99.5%, and the initial discharge capacity of the regenerated positive electrode material at a current density of 0.1C is 124.8 mAh·g -1 After 50 cycles, the capacity retention rate was 91.2%.

[0053] Example 3

[0054] A method for selectively recovering valuable metals from waste ternary lithium batteries and synthesizing regenerated positive electrode materials, the process flow chart of which is as follows: Figure 1 As shown, it includes four parts: pretreatment of waste lithium-ion batteries, carbon thermal reduction roasting of positive electrode materials, selective leaching of Li from carbon thermal reduction products, and synthesis of regenerated ternary materials, specifically including the following steps:

[0055] (1) Carbothermal reduction: 4.5 g of the pretreated positive electrode material and 0.5 g of carbon powder (carbon powder accounts for 10%) were mixed evenly and placed in a corundum boat, and the corundum boat was placed in a tube furnace, and the tube furnace was heated at a rate of 10°C / min in a nitrogen atmosphere, and the calcination temperature was 650°C for 1.5 h. After cooling to room temperature, the mixture was taken out and ground through a 100-mesh sieve to obtain a carbothermal reduction product.

[0056] (2) Ultrapure water leaching: 3 g of the carbon thermal reduction product, 300 mL of ultrapure water and a stirring bar were placed in a 500 mL beaker. After stirring and leaching for 1 h at room temperature, the carbon thermal reduction product leaching solution and water leaching residue were obtained by filtration.

[0057] (3) Evaporation crystallization: Take 300 mL of the carbon thermal reduction product leaching solution and place it in a beaker. Heat and boil until about 15 mL of solution remains in the beaker. Place it in an electric constant temperature blast drying oven at 85°C and dry it for 12 hours to ensure that the liquid in the beaker is completely evaporated. Collect the Li2CO3 product.

[0058] (4) Preparation of ternary precursor: 2 g of water-leached slag was placed in an alumina crucible, the crucible was placed in a tubular furnace, and O2 was introduced for calcination at a temperature of 750 °C for 2 h.

[0059] (5) High-temperature solid phase: 2 g of the ternary precursor was mixed with Li2CO3 at a molar ratio of Li / Me = 1.05:1 for 15 min, and the uniformly mixed powder was placed in a tube furnace and calcined by passing O2 at a heating rate of 10 °C / min. The material was first pre-calcined at 500 °C for 5 h, then heated to 800 °C for 10 h, manually ground and sieved through a 200-mesh sieve to obtain a regenerated positive electrode material.

[0060] (6) Testing of regenerated positive electrode materials: The regenerated positive electrode materials were prepared into CR2032 type coin cells and the charge / discharge tests were performed between 3.00-4.50V using a battery tester.

[0061] The Li leaching efficiency of this embodiment is 93.5%, the purity of Li2CO3 is 99.6%, and the initial discharge capacity of the regenerated positive electrode material at a current density of 0.1C is 130.2mAh·g -1 After 50 cycles, the capacity retention rate was 92.3%.

[0062] Example 4

[0063] A method for selectively recovering valuable metals from waste ternary lithium batteries and synthesizing regenerated positive electrode materials, the process flow chart of which is as follows: Figure 1 As shown, it includes four parts: pretreatment of waste lithium-ion batteries, carbon thermal reduction roasting of positive electrode materials, selective leaching of Li from carbon thermal reduction products, and synthesis of regenerated ternary materials, specifically including the following steps:

[0064] (1) Carbothermal reduction: 4.5 g of the pretreated positive electrode material and 0.5 g of carbon powder (carbon powder accounts for 10%) were mixed evenly and placed in a corundum boat, and the corundum boat was placed in a tube furnace, and the tube furnace was heated at a rate of 10°C / min in a nitrogen atmosphere, and the calcination temperature was 650°C for 1.5 h. After cooling to room temperature, the mixture was taken out and ground through a 100-mesh sieve to obtain a carbothermal reduction product.

[0065] (2) Ultrapure water leaching: 3 g of the carbon thermal reduction product, 300 mL of ultrapure water and a stirring bar were placed in a 500 mL beaker. After stirring and leaching for 1 h at room temperature, the carbon thermal reduction product leaching solution and water leaching residue were obtained by filtration.

[0066] (3) Evaporation crystallization: Take 300 mL of the carbon thermal reduction product leaching solution and place it in a beaker. Heat and boil until about 15 mL of solution remains in the beaker. Place it in an electric constant temperature blast drying oven at 85°C and dry it for 12 hours to ensure that the liquid in the beaker is completely evaporated. Collect the Li2CO3 product.

[0067] (4) Preparation of ternary precursor: 2 g of water-leached slag was placed in an alumina crucible, the crucible was placed in a tubular furnace, and O2 was introduced for calcination at a temperature of 750 °C for 2 h.

[0068] (5) High-temperature solid phase: 2 g of the ternary precursor was mixed with Li2CO3 at a molar ratio of Li / Me = 1.05:1 for 15 min, and the uniformly mixed powder was placed in a tube furnace and calcined by passing O2 at a heating rate of 10 °C / min. The material was first pre-calcined at 500 °C for 5 h, then heated to 850 °C for 8 h, manually ground and sieved through a 200-mesh sieve to obtain a regenerated positive electrode material.

[0069] (6) Testing of regenerated positive electrode materials: The regenerated positive electrode materials were prepared into CR2032 type coin cells and the charge / discharge tests were performed between 3.00-4.50V using a battery tester.

[0070] The Li leaching efficiency of this embodiment is 92.3%, the purity of Li2CO3 is 99.7%, and the initial discharge capacity of the regenerated positive electrode material at a current density of 0.1C is 125.9 mAh·g -1 , the capacity retention rate after 50 cycles is 90.4%.

[0071] Example 5

[0072] A method for selectively recovering valuable metals from waste ternary lithium batteries and synthesizing regenerated positive electrode materials, the process flow chart of which is as follows: Figure 1As shown, it includes four parts: pretreatment of waste lithium-ion batteries, carbon thermal reduction roasting of positive electrode materials, selective leaching of Li from carbon thermal reduction products, and synthesis of regenerated ternary materials, specifically including the following steps:

[0073] (1) Carbothermal reduction: 4.5 g of the pretreated positive electrode material and 0.5 g of carbon powder (carbon powder accounts for 10%) were mixed evenly and placed in a corundum boat, and the corundum boat was placed in a tube furnace, and the tube furnace was heated at a rate of 10°C / min in a nitrogen atmosphere, and the calcination temperature was 650°C for 1.5 h. After cooling to room temperature, the mixture was taken out and ground through a 100-mesh sieve to obtain a carbothermal reduction product.

[0074] (2) Ultrapure water leaching: 3 g of the carbon thermal reduction product, 300 mL of ultrapure water and a stirring bar were placed in a 500 mL beaker. After stirring and leaching for 1 h at room temperature, the carbon thermal reduction product leaching solution and water leaching residue were obtained by filtration.

[0075] (3) Evaporation crystallization: Take 300 mL of the carbon thermal reduction product leaching solution and place it in a beaker. Heat and boil until about 15 mL of solution remains in the beaker. Place it in an electric constant temperature blast drying oven at 85°C and dry it for 12 hours to ensure that the liquid in the beaker is completely evaporated. Collect the Li2CO3 product.

[0076] (4) Preparation of ternary precursor: 2 g of water-leached slag was placed in an alumina crucible, the crucible was placed in a tubular furnace, and O2 was introduced for calcination at a temperature of 750 °C for 2 h.

[0077] (5) High-temperature solid phase: 2 g of the ternary precursor was mixed with Li2CO3 at a molar ratio of Li / Me = 1.08:1 for 15 min, and the uniformly mixed powder was placed in a tube furnace and calcined by passing O2 at a heating rate of 10 °C / min. The material was first pre-calcined at 500 °C for 5 h, then heated to 850 °C for 10 h, manually ground and sieved through a 200-mesh sieve to obtain a regenerated positive electrode material.

[0078] (6) Testing of regenerated positive electrode materials: The regenerated positive electrode materials were prepared into CR2032 type coin cells and the charge / discharge tests were performed between 3.00-4.50V using a battery tester.

[0079] The Li leaching efficiency of this embodiment is 92.7%, the purity of Li2CO3 is 99.6%, and the initial discharge capacity of the regenerated positive electrode material at a current density of 0.1C is 132.4 mAh·g -1 After 50 cycles, the capacity retention rate was 91.7%.

[0080] The foregoing description of specific exemplary embodiments of the present invention is for the purpose of illustration and demonstration. These descriptions are not intended to limit the present invention to the precise form disclosed, and it is clear that many changes and variations can be made based on the above teachings. The purpose of selecting and describing the exemplary embodiments is to explain the specific principles of the present invention and its practical application, so that those skilled in the art can realize and utilize various different exemplary embodiments of the present invention and various different selections and changes. The scope of the present invention is intended to be limited by the claims and their equivalents.

Claims

1. A method for selectively recovering valuable metals from waste ternary lithium batteries and synthesizing regenerated positive electrode materials, characterized in that: The following steps are involved: (1) Pre-treating the waste ternary lithium battery to separate the negative electrode carbon powder material and the positive electrode material; (2) mixing the positive electrode material and the carbon powder, reacting them in a nitrogen atmosphere at a certain temperature to obtain a carbon thermal reduction product; (3) adding the carbon thermal reduction product into water for leaching reaction, and then filtering to obtain a carbon thermal reduction product leaching solution and water leaching residue; (4) evaporating and crystallizing the carbon thermal reduction product leaching solution to obtain Li2CO3, and oxidizing and roasting the water leached residue to obtain a ternary precursor; (5) Li2CO3 and the ternary precursor are fully ground and mixed, and then subjected to a two-step heat treatment reaction to obtain a regenerated positive electrode material.

2. The method for selectively recovering valuable metals from waste ternary lithium batteries and synthesizing regenerated positive electrode materials according to claim 1, characterized in that: The pretreatment of step (1) includes: 1) Discharge the waste ternary lithium battery and separate the positive electrode sheet and the negative electrode sheet; 2) The carbon powder of the negative electrode plate is ground and sieved to obtain a carbon powder sample, and the positive electrode plate is alkali-leached, ground and sieved to obtain a positive electrode material.

3. The method for selectively recovering valuable metals from waste ternary lithium batteries and synthesizing regenerated positive electrode materials according to claim 1, characterized in that: The discharge in step 1) is as follows: placing the waste ternary lithium-ion battery in a 10-30wt% NaCl solution for discharge for 24-48h.

4. The method for selectively recovering valuable metals from waste ternary lithium batteries and synthesizing regenerated positive electrode materials according to claim 1, characterized in that: Step 2) alkali leaching treatment is to place in an alkaline solution with a solid-liquid ratio of 20-25 g / L, a reaction temperature of 50-70° C., and a reaction time of 30-120 min; wherein the alkali solution is a NaOH solution or a KOH solution, and the concentration of the alkali solution is 0.5-3 mol / L.

5. The method for selectively recovering valuable metals from waste ternary lithium batteries and synthesizing regenerated positive electrode materials according to claim 1, characterized in that: In step (2), the temperature for the mixed reaction of the positive electrode material and the carbon powder is 550-750° C., and the reaction time is 30-180 min. The carbon powder accounts for 5-25% of the mass of the mixed powder.

6. The method for selectively recovering valuable metals from waste ternary lithium batteries and synthesizing regenerated positive electrode materials according to claim 1, characterized in that: In step (3), the solid-to-liquid ratio of the carbon thermal reduction product and water is 10-60 g / L, and the reaction is carried out at room temperature for 30-150 min; preferably, the water is ultrapure water.

7. The method for selectively recovering valuable metals from waste ternary lithium batteries and synthesizing regenerated positive electrode materials according to claim 1, characterized in that: In step (4), the carbon thermal reduction product leaching solution is first boiled and then evaporated and crystallized. The evaporation and crystallization temperature is 80-95° C. and the evaporation and crystallization time is 1-10 hours.

8. The method for selectively recovering valuable metals from waste ternary lithium batteries and synthesizing regenerated positive electrode materials according to claim 1, characterized in that: The calcination conditions of the water-leached slag in step (4) are as follows: a calcination temperature of 700-800° C. and a calcination time of 60-120 min in an oxygen atmosphere.

9. The method for selectively recovering valuable metals from waste ternary lithium batteries and synthesizing regenerated positive electrode materials according to claim 1, characterized in that: In step (5), the molar ratio of Li2CO3 and the ternary precursor to be ground and mixed is Li / Me=1.02-1.

08.

10. The method for selectively recovering valuable metals from waste ternary lithium batteries and synthesizing regenerated positive electrode materials according to claim 1, characterized in that: The two-step heat treatment reaction in step (5) includes: preheating at 500-600°C for 2-8h and then heating to 750-950°C under an oxygen atmosphere for 8-12h to obtain a regenerated positive electrode material.

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