CN115679103A - A recycling process for positive electrode materials of decommissioned ternary lithium batteries - Google Patents

Abstract

The invention provides a recycling process for positive electrode materials of decommissioned ternary lithium batteries, comprising the following steps: A) treating the positive electrode sheets of waste ternary lithium batteries to obtain positive electrode active materials; The positive active material is filtered after treatment to obtain a filtrate and a filtered product, and the eluent is selected from a persulfate solution; C) the filtered product is subjected to hydrothermal resulfurization and then annealed to obtain a positive active material; D) The pH of the filtrate is adjusted to recover lithium metal. The eluent used in the invention can effectively separate the valuable metals in the active material of the positive electrode material, and can be reused, reducing the recovery cost. In addition, hydrothermal resulfurization is used to treat the eluted products, which avoids the extraction of valuable metals one by one, optimizes the recovery process, and prevents the use of extractants from polluting the environment. The materials used are more efficient than existing methods. It is cheap and easy to get, and it also achieves energy saving and environmental protection.

Description

A recycling process for positive electrode materials of decommissioned ternary lithium batteries

technical field

The invention belongs to the technical field of lithium ion batteries, and in particular relates to a process for recycling positive electrode materials of decommissioned ternary lithium batteries.

Background technique

Lithium-ion batteries are widely used in mobile phones, cameras, electric vehicles and other fields due to their small size, light weight, and high specific capacity. After lithium batteries are used in large quantities, the recycling of retired lithium batteries has become a problem we need to solve question. Effective recycling of decommissioned lithium batteries reduces the pollution of nickel, cobalt, manganese and other valuable metals to the environment, and can also alleviate the problem of resource shortage. Nowadays, the recycling of decommissioned lithium batteries is mainly divided into pyrometallurgy and hydrometallurgy. Pyrometallurgy consumes a lot of energy and the recycling cost is high; hydrometallurgy has a long operation process and needs to separate valuable metals one by one. Excessive use will pollute the environment and increase the cost of recycling. Energy-saving and environment-friendly recycling of decommissioned lithium batteries has become the focus of current research.

Contents of the invention

In view of this, the technical problem to be solved by the present invention is to provide a recycling process for positive electrode materials of decommissioned ternary lithium batteries. The process flow provided by the present invention is simple, and active materials can be effectively recovered and regenerated.

The present invention provides a recycling process for positive electrode materials of decommissioned ternary lithium batteries, comprising the following steps:

A) After treating the positive electrode sheet of the waste ternary lithium battery, the positive electrode active material is obtained;

B) filtering the positive active material after treatment with an eluent to obtain a filtrate and a filtered product, the eluent being selected from a persulfate solution;

C) annealing the filtered product after hydrothermal resulfurization to obtain a positive active material;

D) adjusting the pH of the filtrate to recover lithium metal.

Preferably, step A) comprises the following steps:

A1) Soak the waste ternary lithium battery in saturated salt water for discharge treatment;

Clean the discharged waste ternary lithium battery with clean water and dry it;

Cut and break the dried battery into battery slices;

Separation of battery positive electrode, negative electrode, casing and separator by flotation;

A2) placing the positive electrode sheet in the treatment solution for heating and stirring, and then filtering to obtain a filtered product;

The filtered product is sieved to obtain a positive electrode active material.

Preferably, the treatment liquid includes a solvent and a solute, the solvent is selected from one or more of ethylene glycol, glycerol, butanediol, and the solute is selected from xylitol, glucose, urea, cholerin One or more of alkalis;

The molar ratio of the solute to the solvent in the treatment solution is (1.5-2.5):1, and the solid-to-liquid mass-volume ratio of the positive electrode sheet to the treatment solution is 1g:(20-25)ml.

Preferably, in step A2), the temperature of the heating and stirring is 150-200° C., and the time is 3-5 hours.

Preferably, the persulfate is selected from sodium persulfate or potassium persulfate;

The solvent in the solution of the persulfate is selected from one or more of methanol, ethylene glycol, distilled water;

The concentration of the persulfate solution is 0.2˜1 mol/L.

Preferably, the solid-to-liquid mass-volume ratio of the positive electrode active material to the eluent is 1g:(20-100)ml.

Preferably, in step B), the temperature of the treatment is 30-90° C., and the treatment time is 2-8 hours.

Preferably, the solid-to-liquid mass volume ratio of the filtered product and the additive for hydrothermal resulfurization is 1 g: (5-20) ml, and the additive for hydrothermal resulfurization is selected from one of NaOH, LiOH, KOH or Various, the concentration of ^OH- in the additive for hydrothermal resulfurization is 2-4.5mol/L;

The temperature of the hydrothermal resulfurization is 150-250° C., and the time is 1-6 hours.

Preferably, a lithium-containing compound is added in the annealing operation, the annealing temperature is 500-900° C., and the annealing time is 2-10 h.

Preferably, the method for reclaiming metal lithium:

Adjust the pH to 10-12, and add water-soluble carbonate, so that lithium ions are precipitated as lithium carbonate.

Compared with the prior art, the present invention provides a recycling process for the cathode material of a decommissioned ternary lithium battery, comprising the following steps: A) treating the positive electrode sheet of the waste ternary lithium battery to obtain the positive electrode active material; B) treating the positive active material with an eluent and then filtering to obtain a filtrate and a filtered product, the eluent being selected from a persulfate solution; C) annealing the filtered product after hydrothermal resulfurization, Obtaining the positive electrode active material; D) adjusting the pH of the filtrate to reclaim metal lithium. The eluent used in the invention can effectively separate the valuable metals in the active material of the positive electrode material, and can be reused, reducing the recovery cost. In addition, hydrothermal resulfurization is used to treat the eluted products, which avoids the extraction of valuable metals one by one, optimizes the recovery process, and prevents the use of extractants from polluting the environment. The materials used are more efficient than existing methods. It is cheap and easy to obtain, which further reduces the recycling cost, and also achieves energy saving and environmental protection.

Description of drawings

Fig. 1 is the process flow diagram of recycling and regeneration of positive electrode material of decommissioned ternary lithium battery provided by the present invention;

Fig. 2 is the battery cycle efficiency figure of embodiment 1;

Fig. 3 is the battery cycle efficiency figure of embodiment 2;

Fig. 4 is the battery cycle efficiency figure of embodiment 3;

FIG. 5 is a graph of battery cycle efficiency of Example 4. FIG.

Detailed ways

The present invention provides a recycling process for positive electrode materials of decommissioned ternary lithium batteries, comprising the following steps:

A) After treating the positive electrode sheet of the waste ternary lithium battery, the positive electrode active material is obtained;

B) filtering the positive active material after treatment with an eluent to obtain a filtrate and a filtered product, the eluent being selected from a persulfate solution;

C) annealing the filtered product after hydrothermal resulfurization to obtain a positive active material;

D) adjusting the pH of the filtrate to recover lithium metal.

The present invention first separates the positive active material from the waste ternary lithium battery, specifically comprising the following steps:

A1) Soak the waste ternary lithium battery in saturated salt water for discharge treatment;

Clean the discharged waste ternary lithium battery with clean water and dry it;

Cut and break the dried battery into battery slices;

Separation of battery positive electrode, negative electrode, casing and separator by flotation;

A2) placing the positive electrode sheet in the treatment solution for heating and stirring, and then filtering to obtain a filtered product;

The filtered product is sieved to obtain a positive electrode active material.

Wherein, the size of the battery slice is 1-2 cm;

The present invention has no special limitation on the specific method of the flotation method, and any method known to those skilled in the art will suffice.

Described treatment liquid comprises solvent and solute, and described solvent is selected from one or more in ethylene glycol, glycerol, butanediol, and described solute is selected from xylitol, glucose, urea, choline chloride One or more; In some specific embodiments of the present invention, the treatment solution is a mixed solution of choline chloride and butanediol.

The molar ratio of solute and solvent in the treatment liquid is (1.5～2.5):1, preferably 1.5:1, 2.0:1, 2.5:1, or any value between (1.5～2.5):1. The solid-to-liquid mass-volume ratio of the positive electrode sheet to the treatment solution is 1g: (20-25)ml, preferably 1g: 20ml, 1g: 22.5ml, 1g: 25ml, or any value between 1g: (20-25)ml .

In the present invention, the mass-to-volume ratio of solid to liquid is expressed in units of g:ml.

The heating and stirring temperature is 150-200°C, preferably 150, 160, 175, 190, 200, or any value between 150-200°C, and the time is 3-5h, preferably 3, 3.5, 4, 4.5 , 5, or any value between 3 and 5h.

After the heating and stirring treatment is completed, filter is performed, and after filtering, the filter residue is sieved to separate the larger aluminum foil from the positive electrode active material.

After the positive electrode active material is obtained, the positive electrode active material is treated with an eluent and then filtered to obtain a filtrate and a filtered product, and the eluent is selected from a persulfate solution.

Described eluent comprises solvent and solute, and described solvent is selected from one or more in methanol, ethylene glycol, distilled water, and described solute is selected from one or more in persulfate, preferably, described The persulfate is selected from sodium persulfate or potassium persulfate;

The solid-to-liquid mass volume ratio of the positive electrode active material to the eluent is 1g:(20-100)ml, preferably 1g:20ml, 1g:40ml, 1g:60ml, 1g:80ml, 1g:100ml, or 1g: Any value between (20～100)ml, the concentration of eluent is 0.2～1mol/L, preferably 0.2mol/L, 0.4mol/L, 0.6mol/L, 0.8mol/L, 1.0mol /L, or any value between 0.2 and 1mol/L.

In the present invention, the positive electrode active material is soaked in an eluent and filtered to obtain a soaking solution and a filtered product. Wherein, the temperature of the soaking treatment is 30-90°C, preferably 30, 50, 60, 80, 90, or any value between 30-90°C, and the time is 2-8 hours, preferably 2, 4, 6 hours , 8, or any value between 2 and 8h.

After the filtered product is dried, hydrothermal resulfurization is carried out. The drying temperature is 80-150°C, preferably 80, 100, 120, 150, or any value between 80-150°C.

In the present invention, the solid-to-liquid mass volume ratio of the filtered product and the hydrothermal resulfurization additive is 1g: (5-20) ml, preferably 1g: 5ml, 1g: 10ml, 1g: 15ml, 1g: 20ml, Or 1g: any value between (5-20)ml.

The additive for hydrothermal resulfurization is selected from one or more of NaOH, LiOH, and KOH, and the concentration of ^OH- in the additive for hydrothermal resulfurization is 2 to 4.5 mol/L, preferably 2, 2.5, 3, 3.5, 4, 4.5, or any value between 2 and 4.5mol/L;

The temperature of the hydrothermal resulfurization is 150-250°C, preferably 150, 170, 200, 230, 250, or any value between 150-250°C, and the time is 1-6 hours, preferably 1, 2, 3 hours , 5, 6, or any value between 1 and 6h.

After the hydrothermal resulfurization product is dried, it is annealed to obtain the positive electrode material active material.

A lithium-containing compound is added in the annealing operation, the annealing temperature is 500-1000°C, preferably 500, 600, 700, 800, 900, 1000, or any value between 500-1000°C, and the annealing time is 2 ~10h, preferably 2, 4, 6, 8, 10, or any value between 2-10. The lithium-containing compound is selected from _Li2CO3 or _LiOH , and the amount of the lithium-containing compound added is excessive compared to the filtered product. In the present invention, the added amount of the lithium-containing compound accounts for the molar percentage of the filtered product 3% to 5%, preferably 3%.

Adjust the pH of the reaction solution after the elution treatment to 10-12, preferably 10, 11, 12, or any value between 10-12, and add a water-soluble carbonate, preferably sodium carbonate or potassium carbonate, so that lithium ions Precipitate with lithium carbonate, recover metal lithium.

Referring to Fig. 1, Fig. 1 is a flow chart of the process flow chart of recycling the anode material of decommissioned ternary lithium battery provided by the present invention.

For the separation of active substances, the present invention uses a binder solution, which reduces energy consumption and environmental pollution compared with high-temperature burning and NMP and DMF solvent dissolution. After the active material of the positive electrode material is extracted, it is treated with an eluent to separate the complex transition metal oxides, and then directly regenerated by hydrothermal resulfurization to obtain the active material. It simplifies the recovery without using strong acid and extractant. The process reduces the pollution to the environment. At the same time, the hydrothermal additive used is cheaper than the existing method, which also reduces the cost of recycling, making the entire recycling process energy-saving and environmentally friendly.

In order to further understand the present invention, the recycling process of the positive electrode material of the decommissioned ternary lithium battery provided by the present invention will be described below in conjunction with the examples, and the scope of protection of the present invention is not limited by the following examples.

Example 1.

1. Soak the waste ternary lithium battery NCM523 in saturated salt water for 12 hours;

2. Wash the discharged waste ternary lithium battery NCM523 repeatedly with clean water several times and dry it;

3. Cut and break the dried battery into battery slices with a diameter of 1 cm;

4. Separation of pole piece, shell and diaphragm by flotation method;

5. Soak the positive electrode sheet in a solvent that is uniformly mixed with choline chloride and butanediol. The molar ratio of choline chloride and butanediol is 2:1, and the heating temperature is 180°C. Soak and stir for 5 hours. Liquid mass volume ratio (g:ml) is 1:20;

6. After soaking and filtering, the filter residue is screened to separate the larger aluminum foil from the active substance;

7. Soak the active substance in K ₂ S ₂ O ₈ solution, the K ₂ S ₂ O ₈ concentration is 0.2mol/L, the elution temperature is 60°C, the time is 4h, and the solid-liquid mass volume ratio is (g: ml) is 1:50;

8. After elution and filtration, the filtrate and the filtered product are separated;

9. Put the filtered product and LiOH solution into the reactor together for hydrothermal reaction, wherein the concentration of LiOH solution is 4mol/L, the temperature of the hydrothermal reaction is 220°C, the time is 3h, the mass-volume ratio of solid to liquid (g:ml) is 1:20;

10. Rinse the hydrothermal product repeatedly with deionized water and dry it in a vacuum oven at 60°C, then mix it with 3% excess Li ₂ CO ₃ for annealing, the annealing temperature is 850°C, and the time is 4h ;

11. Adjust the pH of the filtrate to be 11, add sodium carbonate to precipitate lithium in the form of lithium carbonate, rinse with deionized water repeatedly and then dry.

Example 2.

1. Soak the waste ternary lithium battery NCM523 in saturated salt water for 12 hours;

2. Wash the discharged waste ternary lithium battery NCM523 repeatedly with clean water several times and dry it;

3. Cut and break the dried battery into battery slices with a diameter of 1 cm;

4. Separation of pole piece, shell and diaphragm by flotation method;

5. Soak the positive electrode sheet in a solvent that is uniformly mixed with choline chloride and butanediol. The molar ratio of choline chloride and butanediol is 2:1, and the heating temperature is 180°C. Soak and stir for 5 hours. Liquid mass volume ratio (g:ml) is 1:20;

6. After soaking and filtering, the filter residue is screened to separate the larger aluminum foil from the active substance;

7. Soak the active substance in K ₂ S ₂ O ₈ solution, the K ₂ S ₂ O ₈ concentration is 0.2mol/L, the elution temperature is 70°C, the time is 4h, and the solid-liquid mass volume ratio is (g: ml) is 1:50;

8. After elution and filtration, the filtrate and the filtered product are separated;

9. Put the filtered product and the mixed solution of LiOH and KOH into the reactor together for hydrothermal reaction. In the mixed solution, the concentration of LiOH solution is 0.1mol/L, the concentration of KOH solution is 3.9mol/L, water The temperature of the thermal reaction is 220°C, the time is 3 hours, and the solid-liquid mass-volume ratio (g:ml) is 1:20;

10. Rinse the hydrothermal product repeatedly with deionized water and dry it in a vacuum oven at 60°C, then mix it with 3% excess Li ₂ CO ₃ for annealing, the annealing temperature is 850°C, and the time is 5h ;

11. Adjust the pH of the filtrate to be 11, add sodium carbonate to precipitate lithium in the form of lithium carbonate, rinse with deionized water repeatedly and then dry.

Example 3.

1. Soak the waste ternary lithium battery NCM523 in saturated salt water for 12 hours;

2. Wash the discharged waste ternary lithium battery NCM523 repeatedly with clean water several times and dry it;

3. Cut and break the dried battery into battery slices with a diameter of 1 cm;

4. Separation of pole piece, shell and diaphragm by flotation method;

5. Soak the positive electrode sheet in a solvent that is uniformly mixed with choline chloride and butanediol. The molar ratio of choline chloride and butanediol is 2:1, and the heating temperature is 180°C. Soak and stir for 5 hours. Liquid mass volume ratio (g:ml) is 1:20;

6. After soaking and filtering, the filter residue is screened to separate the larger aluminum foil from the active substance;

7. Soak the active substance in K ₂ S ₂ O ₈ solution, the K ₂ S ₂ O ₈ concentration is 0.2mol/L, the elution temperature is 70°C, the time is 5h, and the solid-liquid mass volume ratio is (g: ml) is 1:50;

8. After elution and filtration, the filtrate and the filtered product are separated;

9. Put the filtered product and the mixed solution of LiOH and KOH into the reactor together for hydrothermal reaction. In the mixed solution, the concentration of LiOH solution is 0.1mol/L, the concentration of KOH solution is 3.9mol/L, water The temperature of the thermal reaction is 220°C, the time is 4 hours, and the solid-liquid mass-volume ratio (g:ml) is 1:20;

10. Rinse the hydrothermal product repeatedly with deionized water and dry it in a vacuum oven at 60°C, then mix it with 3% excess Li ₂ CO ₃ for annealing, the annealing temperature is 850°C, and the time is 5h ;

11. Adjust the pH of the filtrate to be 11, add sodium carbonate to precipitate lithium in the form of lithium carbonate, rinse with deionized water repeatedly and then dry.

Example 4.

1. Soak the waste ternary lithium battery NCM523 in saturated salt water for 12 hours;

2. Wash the discharged waste ternary lithium battery NCM523 repeatedly with clean water several times and dry it;

3. Cut and break the dried battery into battery slices with a diameter of 1 cm;

4. Separation of pole piece, shell and diaphragm by flotation method;

5. Soak the positive electrode sheet in a solvent that is uniformly mixed with choline chloride and butanediol. The molar ratio of choline chloride and butanediol is 2:1, and the heating temperature is 180°C. Soak and stir for 5 hours. Liquid mass volume ratio (g:ml) is 1:20;

6. After soaking and filtering, the filter residue is screened to separate the larger aluminum foil from the active substance;

7. Soak the active substance in Na ₂ S ₂ O ₈ solution, the concentration of Na ₂ S ₂ O ₈ is 0.2mol/L, the elution temperature is 70°C, the time is 5h, and the solid-liquid mass volume ratio is (g: ml) is 1:50;

8. After elution and filtration, the filtrate and the filtered product are separated;

9. Put the filtered product and the mixed solution of LiOH and KOH into the reactor together for hydrothermal reaction. In the mixed solution, the concentration of LiOH solution is 0.1mol/L, the concentration of KOH solution is 3.9mol/L, water The temperature of the thermal reaction is 220°C, the time is 4 hours, and the solid-liquid mass-volume ratio (g:ml) is 1:20;

10. Rinse the hydrothermal product repeatedly with deionized water and dry it in a vacuum oven at 60°C, then mix it with 3% excess Li ₂ CO ₃ for annealing, the annealing temperature is 850°C, and the time is 5h ;

11. Adjust the pH of the filtrate to be 11, add sodium carbonate to precipitate lithium in the form of lithium carbonate, rinse with deionized water repeatedly and then dry.

To assemble the battery from the above recycled materials, the specific steps are:

The material was prepared as a slurry with 80wt% recycled material, 10wt% Super P and 10wt% PVDF, coated on aluminum foil and dried in a vacuum oven at 110°C for 12h, where PVDF was added in the form of dissolving NMP. The dried aluminum foil was punched into a disc with a diameter of 12 mm, and a CR2032 coin half cell was used for assembly in a glove box.

Result is referring to Fig. 2～Fig. 5, and Fig. 2 is the battery cycle efficiency figure of embodiment 1; Fig. 3 is the battery cycle efficiency figure of embodiment 2; Fig. 4 is the battery cycle efficiency figure of embodiment 3; Fig. 5 is embodiment 4 The battery cycle efficiency diagram. It can be seen from Figure 4 that when the charge-discharge cycle is performed at a rate of 1C, the first-cycle discharge specific capacity of the battery assembled with recycled electrode materials can reach 170mAh/g, and the discharge specific capacity can still reach 168mAh/g after 50 cycles. It can reach 98.8%; the first-time efficiency is 92.96%, and the efficiency can reach more than 99% after the cycle.

Comparative example 1.

1. Soak the waste ternary lithium battery NCM523 in saturated salt water for 12 hours;

2. Wash the discharged waste ternary lithium battery NCM523 repeatedly with clean water several times and dry it;

3. Cut and break the dried battery into battery slices with a diameter of 1 cm;

4. Separation of pole piece, shell and diaphragm by flotation method;

5. Soak the positive electrode sheet in a solvent that is uniformly mixed with choline chloride and butanediol. The molar ratio of choline chloride and butanediol is 2:1, and the heating temperature is 180°C. Soak and stir for 5 hours. Liquid mass volume ratio (g:ml) is 1:20;

6. After soaking and filtering, the filter residue is screened to separate the larger aluminum foil from the active substance;

7. Soak the active substance in H ₂ C ₂ O ₄ solution, the concentration of H ₂ C ₂ O ₄ is 0.2mol/L, the elution temperature is 70°C, the time is 4h, and the solid-liquid mass volume ratio is (g: ml) is 1:50;

8. After elution and filtration, the filtrate and the filtered product are separated;

The elution effect of lithium is lacking, which affects the subsequent regeneration process.

Comparative example 2.

1. Soak the waste ternary lithium battery NCM523 in saturated salt water for 12 hours;

2. Wash the discharged waste ternary lithium battery NCM523 repeatedly with clean water several times and dry it;

3. Cut and break the dried battery into battery slices with a diameter of 1 cm;

4. Separation of pole piece, shell and diaphragm by flotation method;

5. Soak the positive electrode piece in a solvent that is uniformly mixed with choline chloride and butanediol. The molar ratio of choline chloride and butanediol is 2:1, and the heating temperature is 180°C. Soak and stir for 5 hours. Liquid mass volume ratio (g:ml) is 1:20;

6. After soaking and filtering, the filter residue is screened to separate the larger aluminum foil from the active substance;

7. Soak the active substance in (NH ₄ ) ₂ S ₂ O ₈ solution, the concentration of (NH ₄ ) ₂ S ₂ O ₈ is 0.2mol/L, the elution temperature is 70°C, the time is 5h, the solid-liquid mass The volume ratio (g:ml) is 1:50;

8. After elution and filtration, the filtrate and the filtered product are separated;

During the elution process, the transition metal dissolves seriously, which affects the subsequent regeneration process.

Comparative example 3

1. Soak the waste ternary lithium battery NCM523 in saturated salt water for 12 hours;

2. Wash the discharged waste ternary lithium battery NCM523 repeatedly with clean water several times and dry it;

3. Cut and break the dried battery into battery slices with a diameter of 1 cm;

4. Separation of pole piece, shell and diaphragm by flotation method;

5. Soak the positive electrode piece in a solvent that is uniformly mixed with choline chloride and butanediol. The molar ratio of choline chloride and butanediol is 2:1, and the heating temperature is 180°C. Soak and stir for 5 hours. Liquid mass volume ratio (g:ml) is 1:20;

6. After soaking and filtering, the filter residue is screened to separate the larger aluminum foil from the active substance;

7. Soak the active substance in 100ml of K ₂ S ₂ O ₈ solution, the concentration of K ₂ S ₂ O ₈ is 0.2mol/L, add 10ml of methanol, the elution temperature is 60°C, the time is 4h, the solid-liquid mass The volume ratio (g:ml) is 1:50;

8. After elution and filtration, the filtrate and the filtered product are separated;

During the elution process, the transition metal dissolves seriously, which affects the subsequent regeneration process.

The ICP test was carried out on the filtered product, the ion concentration was measured, and the elution effect was calculated. The results are shown in Table 1.

Table 1 The elution effect of the filtered product

Elution rate Li Ni co mn Example 1 94.53% 0.35% 0.30% 0.52% Example 2 95.31% 0.32% 0.28% 0.47% Example 3 97.42% 0.3% 0.25% 0.45% Example 4 96.89% 0.32% 0.27% 0.45% Comparative example 1 86.41% 1.30% 1.27% 1.32% Comparative example 2 95.32% 6.32% 3.28% 9.45% Comparative example 3 96.75% 7.4% 5.46% 11.25%

It can be seen from Table 1 that Na ₂ S ₂ O ₈ , Na ₂ S ₂ O ₈ and (NH ₄ ) ₂ S ₂ O ₈ all have good elution effects on lithium in ternary materials, but (NH ₄ ) ₂ S ₂ O ₈ also elutes other transition metals. Adding a small amount of methanol to the persulfate solution improves the elution rate of lithium, but at the same time it increases the elution rate of transition metals. The H ₂ C ₂ O ₄ solution for lithium The elution effect is not as good as the above-mentioned persulfates, and the elution rate of transition metals is also higher.

The above is only a preferred embodiment of the present invention, it should be pointed out that for those skilled in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, and these improvements and modifications are also It should be regarded as the protection scope of the present invention.

Claims (10)

1. A recycling process of a retired ternary lithium battery positive electrode material is characterized by comprising the following steps:

a) Processing a positive plate of a waste ternary lithium battery to obtain a positive active substance;

b) Treating the positive active substance with an eluent, and filtering to obtain a filtrate and a filtered product, wherein the eluent is selected from a persulfate solution;

c) Carrying out hydrothermal resulfurization and annealing treatment on the filtered product to obtain a positive active substance;

d) And adjusting the pH value of the filtrate, and recovering the lithium metal.

2. Regeneration process according to claim 1, characterized in that step a) comprises the following steps:

a1 Soaking the waste ternary lithium battery in saturated salt water for discharging treatment;

cleaning and drying the discharged waste ternary lithium battery by using clear water;

shearing and crushing the dried battery into battery slices;

separating a positive plate, a negative plate, a shell and a diaphragm of the battery by a flotation method;

a2 Placing the positive plate in a treatment solution, heating and stirring, and then filtering to obtain a filtered product;

and screening the filtered product to obtain the positive active substance.

3. The regeneration process of claim 2, wherein the treatment fluid comprises a solvent selected from one or more of ethylene glycol, glycerol, butylene glycol, and a solute selected from one or more of xylitol, glucose, urea, choline chloride;

the molar ratio of solute to solvent in the treatment solution is (1.5-2.5) to 1, and the solid-liquid mass volume ratio of the positive plate to the treatment solution is 1g: (20-25) ml.

4. The regeneration process according to claim 2, wherein in step A2), the heating and stirring temperature is 150 to 200 ℃ and the time is 3 to 5 hours.

5. The regeneration process according to claim 1, wherein the persulfate is selected from sodium persulfate or potassium persulfate;

the solvent in the persulfate solution is selected from one or more of methanol, glycol and distilled water;

the concentration of the persulfate solution is 0.2-1 mol/L.

6. The regeneration process according to claim 1, wherein the solid-liquid mass volume ratio of the positive electrode active material to the eluent is 1g (20-100) ml.

7. The regeneration process according to claim 1, wherein in step B), the temperature of the treatment is 30 to 90 ℃ and the time is 2 to 8 hours.

8. The regeneration process according to claim 1, wherein the solid-liquid mass-to-volume ratio of the filtered product to the hydrothermal revulcanization additive is 1g: (5-20) ml, the additive for hydrothermal revulcanization is selected from one or more of NaOH, liOH and KOH, and OH in the additive for hydrothermal revulcanization ^- The concentration of (A) is 2-4.5 mol/L;

the temperature of the hydrothermal re-sulfurization is 150-250 ℃, and the time is 1-6 h.

9. The regeneration process according to claim 1, wherein a lithium-containing compound is added in the annealing operation, the annealing temperature is 500-900 ℃, and the annealing time is 2-10 h.

10. The regeneration process according to claim 1, characterized in that the method of recovering metallic lithium:

adjusting the pH value to 10-12, and adding water-soluble carbonate to precipitate lithium ions as lithium carbonate.

Images