WO2024021290A1

WO2024021290A1 - Waste lithium battery leachate treatment method and waste lithium battery recovery method

Info

Publication number: WO2024021290A1
Application number: PCT/CN2022/121885
Authority: WO
Inventors: 张金超; 刘少葵; 刘勇奇; 巩勤学; 李长东
Original assignee: 广东邦普循环科技有限公司; 湖南邦普循环科技有限公司
Priority date: 2022-07-28
Filing date: 2022-09-27
Publication date: 2024-02-01
Also published as: CN115028295A

Abstract

The present invention relates to relates to the technical field of lithium battery recovery. Disclosed are a waste lithium battery leachate treatment method and a waste lithium battery recovery method. Iron-aluminum slag generated in the leachate treatment process is subjected to high-temperature calcination, and a high-temperature calcination product is recycled as a Fenton-like catalyst; the pH value of a leachate is adjusted and then the leachate reacts with hydrogen peroxide and the Fenton-like catalyst, so that ferrous ions are converted into ferric ions, and organic matter is also reacted; at the same time, fluorine ions in the leachate can be adsorbed by utilizing the porous characteristics of the Fenton-like catalyst. In the present invention, the waste iron-aluminum slag is recycled, the COD and fluorine content in the leaching process can also be reduced, and the waste slag generated in waste lithium battery recovery is calcinated and then used as a catalyst to catalyze waste liquid generated from the waste slag, thereby achieving use of waste to treat waste; moreover, the original production process is not changed, no other purities are introduced, and the present invention has relatively wide engineering application prospects.

Description

Methods for treating waste lithium battery leachate and recycling methods for waste lithium batteries

Technical field

The present invention relates to the technical field of lithium battery recycling, and specifically to a method for treating waste lithium battery leachate and a method for recycling waste lithium batteries.

Background technique

In the current wet recycling process of used lithium batteries, electrode powder is selectively leached of precious metals through acid leaching. The iron and aluminum ions in the leach solution are often removed by adjusting the pH to generate hydroxide precipitation, thus producing a large amount of solid waste that is difficult to separate. Iron and aluminum slag. In addition, due to the leakage of electrolyte caused by front-end discharge treatment, some COD and fluoride ions exist in the leachate, which affects the service life of equipment and instruments and the quality of back-end products.

In view of this, the present invention is proposed.

Contents of the invention

The purpose of the present invention is to provide a method for treating waste lithium battery leachate and a method for recycling waste lithium battery, aiming to effectively remove COD and fluoride ions in the leachate while recycling iron and aluminum slag.

The present invention is implemented as follows:

In a first aspect, the present invention provides a method for treating waste lithium battery leachate, including:

The leachate is subjected to a primary pH adjustment and then reacts with an oxidant and a Fenton-like catalyst. After the reaction, a secondary pH adjustment is performed, and the iron-aluminum slag and purified leachate are obtained after filtration;

Among them, the preparation process of Fenton-like catalyst includes: calcining iron-aluminum slag at high temperature.

In an optional embodiment, the high-temperature calcination controls the calcination temperature to 800-1000°C and the calcination time to 4-6 hours; and the calcination process is performed in an inert atmosphere;

Preferably, the calcination temperature is 900-1000°C and the calcination time is 4.5-5.5h.

In an optional embodiment, the product calcined at high temperature is pulverized and passed through a 100-200 mesh sieve, and the residue obtained from the sieve is added to the leachate as a Fenton-like catalyst;

Preferably, the oversize material continues to be returned for crushing.

In an optional embodiment, the primary pH adjustment is to adjust the pH value to 2-4, and the secondary pH adjustment is to control the pH value to be 4-6.

In an optional embodiment, both the primary pH value adjustment and the secondary pH value adjustment are adjusted using a sodium carbonate solution with a mass fraction of 10%-30%.

In an optional embodiment, the reaction with the oxidant and Fenton-like catalyst is controlled by controlling the reaction temperature to 60-90°C and the reaction time to 60-120 min;

Preferably, the oxidizing agent is selected from at least one of hydrogen peroxide and manganese dioxide; more preferably, it is hydrogen peroxide;

Preferably, the stirring rate is controlled to 400-600 r/min during the reaction.

In an optional embodiment, the molar ratio of the amount of hydrogen peroxide to the ferrous ions in the leach solution is 1:1-2, and the amount of Fenton-like catalyst added per liter of leach solution is 10-40g;

Preferably, hydrogen peroxide is added at a flow rate of 0.5-1.5 mL/min.

In an optional embodiment, part of the iron-aluminum slag is calcined at high temperature, and the calcined product is used as a Fenton-like catalyst; the remaining iron-aluminum slag is recycled as building materials;

Preferably, the fluorine-containing tail gas generated during the high-temperature calcination process is treated by an absorption device and then discharged.

In a second aspect, the present invention provides a method for recycling waste lithium batteries, including the method for treating waste lithium battery leachate in any one of the aforementioned embodiments;

Among them, the leachate is obtained from waste lithium batteries after acid leaching.

In an optional embodiment, the acid leaching process includes: mixing and leaching used lithium batteries with sulfuric acid, and controlling the pH value of the leaching to be 0.5-1.

The invention has the following beneficial effects: by calcining the iron-aluminum slag produced during the leachate treatment process at high temperature, the high-temperature calcined product is recycled as a Fenton-like catalyst; the pH value of the leachate is adjusted and reacted with hydrogen peroxide and Fenton-like catalyst to make When ferrous ions are converted into ferric ions, organic matter can be reacted. At the same time, the porous characteristics of Fenton-like catalysts can be used to adsorb fluoride ions in the leachate. While recycling scrap iron and aluminum slag, the present invention can also reduce the COD and fluorine content in the leaching process, and can use the waste slag generated in the recycling of used lithium batteries to act as a catalyst after being calcined to catalytically treat the waste liquid produced by itself, achieving It uses waste to treat waste without changing the original production process and without introducing other impurities, so it has great engineering application prospects.

Description of drawings

In order to explain the technical solutions of the embodiments of the present invention more clearly, the drawings required to be used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and therefore do not It should be regarded as a limitation of the scope. For those of ordinary skill in the art, other relevant drawings can be obtained based on these drawings without exerting creative efforts.

Figure 1 is a process flow chart of a method for treating waste lithium battery leachate provided in an embodiment of the present invention;

Figure 2 is a process flow chart of a method for treating waste lithium battery leachate provided in the comparative example of the present invention.

Detailed ways

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. If the specific conditions are not specified in the examples, the conditions should be carried out according to the conventional conditions or the conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not indicated, they are all conventional products that can be purchased commercially.

In view of the problems existing in the existing technology, for example, after the leachate treatment, a large amount of solid waste iron and aluminum slag will be produced that is difficult to separate, and some COD and fluoride ions will still exist after the leachate is treated. The inventor creatively calcined the iron-aluminum slag, and used the obtained magnetic black product as a Fenton-like catalyst. The leachate was treated in the presence of an oxidant, and while ferrous ions were oxidized, Fenton reaction was performed to oxidize and decompose some organic matter; Since the product calcined at high temperature has a large specific surface area, it can also absorb fluoride ions in the leachate. The concept of using waste to treat waste provided by the present invention can effectively remove organic matter and fluoride ions in the leachate without introducing other impurities, and has great engineering application prospects.

Specifically, a method for treating waste lithium battery leachate provided by an embodiment of the present invention, with reference to Figure 1, includes the following steps:

S1. Oxidation and adsorption reaction

The leachate is adjusted to a pH value and then reacted with an oxidant and a Fenton-like catalyst. The Fenton-like catalyst is obtained by calcining the iron-aluminum slag deposited in subsequent steps at high temperature. This step mainly involves the following reactions:

It should be noted that the leachate targeted by the embodiments of the present invention is obtained by acid leaching of waste lithium batteries. The acid leaching process includes: mixing waste lithium batteries with sulfuric acid for leaching, and controlling the pH value of the leaching to 0.5-1. Through acid leaching, metals such as iron and aluminum are dissolved in acid.

Furthermore, the primary pH value adjustment is to adjust the pH value to 2-4. The reaction in this pH value range can make the reaction more complete. If the pH value is too small, the Fenton reaction will not proceed. In some embodiments, the primary pH adjustment is performed using a sodium carbonate solution with a mass fraction of 10%-30%. Since the pH value of the leach solution is small, it is necessary to use an alkaline solution to adjust the pH value before performing the reaction. This may be but is not limited to Sodium carbonate solution, the mass fraction of sodium carbonate solution can be 10%, 15%, 20%, 25%, 30%, etc.

Further, when reacting with the oxidant and Fenton-like catalyst, the reaction temperature is controlled to be 60-90°C, the reaction time is 60-120 min, and the stirring rate is controlled to be 400-600 r/min during the reaction process. Within this temperature range, each reaction can be carried out more fully. If the reaction temperature is too low, it is not conducive to the Fenton reaction to fully proceed; if the reaction temperature is too high, fluoride ions cannot be fully adsorbed.

Specifically, the reaction temperature can be 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, etc., or any value between the above adjacent values; the reaction time can be 60min, 70min , 80min, 90min, 100min, 110min, 120min, etc. It can also be any value between the above adjacent values.

Further, the oxidant is selected from at least one of hydrogen peroxide and manganese dioxide, and may be one or more, which is not limited here. In a preferred embodiment, the oxidizing agent is hydrogen peroxide, which is easily available as a raw material and can effectively oxidize and decompose organic matter.

In some embodiments, the molar ratio of the amount of hydrogen peroxide to the ferrous ions in the leach solution is 1:1-2, and the amount of Fenton-like catalyst added per liter of leach solution is 10-40g; the amount of hydrogen peroxide is 0.5-1.5 mL. /min flow rate was added. In actual operation, the hydrogen peroxide is controlled to be slowly added to the leachate at the above flow rate, and the calcined product powder is slowly added at the same time, and then the reaction is stirred at a constant temperature at the reaction temperature.

Specifically, the molar ratio of the amount of hydrogen peroxide added to the ferrous ions in the leach solution can be 1:1, 1:1.5, 1:2, etc., or can be any value between the above adjacent values; each liter of leach solution corresponds to The amount of Fenton catalyst added can be 10g, 20g, 30g, 40g, etc., or any value between the above adjacent values.

S2, deposited iron and aluminum slag

After the reaction of S1, a secondary pH adjustment is performed. After filtration, the iron-aluminum slag and the purified leachate are obtained. The secondary pH adjustment is to control the pH value to 4-6 to ensure that the iron ions and aluminum ions in the solution are fully contained. precipitation.

Specifically, the secondary pH value adjustment is to control the pH value to 4.0, 4.5, 5.0, 5.5, 6.0, etc., or it can be any value between the above adjacent values.

In some embodiments, both the primary pH value adjustment and the secondary pH value adjustment are adjusted using a sodium carbonate solution with a mass fraction of 10%-30%; in other embodiments, other alkaline solutions can also be used to adjust the pH value. .

S3, high temperature calcination

The obtained iron-aluminum slag is calcined at high temperature. The high-temperature calcination controls the calcination temperature to 800-1000°C and the calcination time to 4-6 hours; and the calcination process is carried out in an inert atmosphere. Preferably, the calcination temperature is 900-1000°C and the calcination time is 4.5-5.5h. The main components of iron-aluminum slag are iron hydroxide, aluminum hydroxide, and nickel hydroxide. The products calcined under oxygen-free conditions are ferric oxide, aluminum oxide, and nickel oxide.

Specifically, the calcination temperature can be 800°C, 850°C, 900°C, 950°C, 1000°C, etc., or any value between the above adjacent values; the calcination time can be 4.0h, 4.5h, 5.0h, 5.5h, 60h, etc., or any value between the above adjacent values.

In some embodiments, the product calcined at high temperature is pulverized, passed through a 100-200 mesh screen, and the product below the screen is taken as a Fenton-like catalyst and added to the leachate; the product above the screen continues to be crushed. Use powders with smaller particle sizes as Fenton-like catalysts to better promote the oxidation reaction and better adsorb fluoride ions.

In actual operations, according to the demand for Fenton-like catalysts, part of the iron-aluminum slag is calcined at high temperature, and the calcined product is used as a Fenton-like catalyst; the remaining iron-aluminum slag is recycled as building materials, and the high-temperature calcination process The fluorine-containing tail gas produced in the wastewater treatment plant is treated by the absorption device and then discharged.

Embodiments of the present invention also provide a method for recycling waste lithium batteries, which includes the above method for treating waste lithium battery leachate; wherein the leachate is obtained by acid leaching of waste lithium batteries. That is, the recycling method of used lithium batteries is to add an initial acid leaching step based on the treatment method of used lithium battery leachate.

The features and performance of the present invention will be described in further detail below with reference to examples.

The leachate treated in the following examples and comparative examples is obtained by acid leaching of waste lithium batteries. The specific process includes: mixing waste lithium batteries with sulfuric acid, stirring at 60°C for 1 hour, and the amount of sulfuric acid used is such that the solution pH=0.6 .

Example 1

This embodiment provides a method for treating waste lithium battery leachate, as shown in Figure 1, including the following steps:

(1) Calculate the iron-aluminum slag generated during the leaching process without oxygen for 4 hours at 800°C to obtain a black calcined product, which is crushed and ground through a 100-mesh screen, and the residue is collected.

(2) Take 1L of leach solution, detect the COD, ferrous ion and fluorine content in the solution, and add 10% sodium carbonate solution to adjust the pH of the leach solution to 3.

(3) Add hydrogen peroxide at a molar ratio of hydrogen peroxide to ferrous ions of 1:2. The hydrogen peroxide is added to the ferrous oxide ions in the leach solution through a peristaltic pump at a flow rate of 1.0 mL/min. Take 20g of the sieved material and add it to the solution. Stir the reaction at 400r/min at 60°C for 60min.

(4) Add a sodium carbonate solution with a mass fraction of 10% to raise the pH of the solution to 4.5 after the reaction, precipitate the iron ions and aluminum ions in the solution, and filter to obtain iron-aluminum slag and qualified leachate;

(5) Return the iron and aluminum slag to (1) for calcination, and detect the COD and fluorine content in the qualified leach solution.

The results show that in Example 1, the COD removal rate is 63.3% and the fluoride ion removal rate is 36.1%; among them, the COD removal rate and the fluoride ion removal rate are calculated according to the following formula:

Example 2

This embodiment provides a method for treating waste lithium battery leachate, which includes the following steps:

(1) Calculate the iron and aluminum slag generated during the leaching process at 900°C for 4 hours without oxygen to obtain a black calcined product. After crushing and grinding, pass through a 200-mesh screen and take the residue.

(3) Add hydrogen peroxide according to the molar ratio of hydrogen peroxide to ferrous ions of 1:2. The hydrogen peroxide is added to the ferrous oxide ions in the leach solution through a peristaltic pump at a flow rate of 1.0 mL/min. Take 20g of the sieved material and add it to the solution at 60°C. Stir the reaction at 400r/min for 120min.

(4) Add 10% mass fraction of sodium carbonate solution to raise the pH of the reacted solution to 4.5 to precipitate the iron ions and aluminum ions in the solution, and filter to obtain iron-aluminum slag and qualified leachate.

The results show that in Example 2, the COD removal rate is 62.2% and the fluoride ion removal rate is 45.5%.

Example 3

(1) Calculate the iron and aluminum slag generated during the leaching process at 900°C for 4 hours without oxygen to obtain a black calcined product, which is crushed and ground through a 200-mesh screen, and the residue is collected.

(3) Add hydrogen peroxide according to the molar ratio of hydrogen peroxide to ferrous ions of 1:2. The hydrogen peroxide is added to the ferrous oxide ions in the leach solution through a peristaltic pump at a flow rate of 1.0 mL/min. Take 20g of the sieved material and add it to the solution at 60°C. Stir the reaction at 400r/min for 240min.

(4) Add 10% mass fraction of sodium carbonate solution to raise the pH of the reacted solution to 4.5 to fully precipitate the iron ions and aluminum ions in the solution, and filter to obtain iron-aluminum slag and qualified leachate.

(5) Return the iron and aluminum slag to (1) for calcination, detect the COD and fluorine content in the qualified leach solution, and calculate the removal rate.

The results show that in Example 3, the COD removal rate is 63.6% and the fluoride ion removal rate is 45.2%.

Example 4

(1) Calculate the iron-aluminum slag produced during the leaching process without oxygen for 6 hours at 800°C to obtain a black calcined product, which is crushed and ground through a 100-mesh screen and the residue is taken out.

(2) Take 1L of the leach solution, detect the COD, ferrous ion and fluorine content in the solution, and add 10% sodium carbonate solution to adjust the pH of the leach solution to 2.

(3) Add hydrogen peroxide at a molar ratio of hydrogen peroxide to ferrous ions of 1:1. The hydrogen peroxide is added to the ferrous oxide ions in the leach solution through a peristaltic pump at a flow rate of 0.5 mL/min. Take 10g of the sieved material and add it to the solution. Stir the reaction at 400r/min at 60°C for 120min.

(4) Add a sodium carbonate solution with a mass fraction of 10% to raise the pH of the solution to 4.0 after the reaction, precipitate the iron ions and aluminum ions in the solution, and filter to obtain iron-aluminum slag and qualified leachate;

The results show that in Example 4, the COD removal rate is 31.3% and the fluoride ion removal rate is 32.5%;

Example 5

(1) Calculate the iron-aluminum slag generated during the leaching process without oxygen for 6 hours at 1000°C to obtain a black calcined product, which is crushed and ground through a 200-mesh screen and the residue is taken out.

(2) Take 1L of the leach solution, detect the COD, ferrous ions and fluorine content in the solution, and add 30% sodium carbonate solution to adjust the pH of the leach solution to 4.

(3) Add hydrogen peroxide at a molar ratio of hydrogen peroxide to ferrous ions of 1:2. The hydrogen peroxide is added to the ferrous oxide ions in the leach solution through a peristaltic pump at a flow rate of 1.5 mL/min. Take 40g of the sieved material and add it to the solution. Stir the reaction at 600r/min at 90°C for 60min.

(4) Add a sodium carbonate solution with a mass fraction of 30% to raise the pH of the solution to 6.0 after the reaction, precipitate the iron ions and aluminum ions in the solution, and filter to obtain iron-aluminum slag and qualified leachate;

The results show that in Example 5, the COD removal rate is 62.5% and the fluoride ion removal rate is 48.7%;

Example 6

This embodiment provides a method for treating waste lithium battery leachate. The only difference from Embodiment 1 is that the pH value is adjusted to 3.5 in step (2).

The results showed that in Example 6, the COD removal rate was 65.1% and the fluoride ion removal rate was 46.8%.

Example 7

This embodiment provides a method for treating waste lithium battery leachate. The only difference from Embodiment 1 is that the pH value is adjusted to 2.0 in step (2).

The results show that in Example 7, the COD removal rate is 32.4% and the fluoride ion removal rate is 30.8%.

Example 8

This embodiment provides a method for treating waste lithium battery leachate. The only difference from Embodiment 1 is that the pH value is adjusted to 4.0 in step (2).

The results showed that in Example 8, the COD removal rate was 64.2% and the fluoride ion removal rate was 45.7%.

Example 9

This embodiment provides a method for treating waste lithium battery leachate. The only difference from Example 1 is that the reaction temperature in step (3) is 70°C.

The results showed that in Example 9, the COD removal rate was 66.8% and the fluoride ion removal rate was 45.2%.

Example 10

This embodiment provides a method for treating waste lithium battery leachate. The only difference from Example 1 is that the reaction temperature in step (3) is 80°C.

The results showed that in Example 10, the COD removal rate was 65.9% and the fluoride ion removal rate was 41.1%.

Example 11

This embodiment provides a method for treating waste lithium battery leachate. The only difference from Example 1 is that the reaction temperature in step (3) is 90°C.

The results showed that in Example 11, the COD removal rate was 52.3% and the fluoride ion removal rate was 37.2%.

Comparative example 1

This comparative example provides a method for treating waste lithium battery leachate, as shown in Figure 2, including the following steps:

(1) Take 1L of leach solution, detect the COD, ferrous ion and fluorine content in the solution, and add 10% mass fraction of sodium carbonate solution to adjust the pH of the leach solution to 3.

(2) Add hydrogen peroxide according to the molar ratio of hydrogen peroxide to ferrous ions of 1:2. The hydrogen peroxide is added to the ferrous oxide ions in the leach solution through a peristaltic pump at a flow rate of 1.0 mL/min. Stir and react at 60°C for 60 minutes. The reaction principle is as follows:

Fe ²⁺ +H ₂ O ₂ →Fe ³⁺ +H ₂ O (organic matter and fluorine are not removed)

(3) Add 10% mass fraction of sodium carbonate solution to raise the pH of the reacted solution to 4.5 to precipitate the iron ions and aluminum ions in the solution, and filter to obtain iron-aluminum slag and qualified leachate.

(4) Detect COD and fluorine content in qualified leachate.

The results show that the COD removal rate in the leaching process of Comparative Example 1 is 31.2%, and the fluorine content is almost unchanged.

Comparative example 2

The only difference from Example 1 is that the pH value is adjusted to 1.5 in step (2).

The results show that the COD removal rate in the leaching process of Comparative Example 1 is 15.2%, and the fluoride ion removal rate is 5.3%.

Comparative example 3

The only difference from Example 1 is that the pH value is adjusted to 5 in step (2).

The results showed that the COD removal rate in the leaching process of Comparative Example 1 was 46.8%, and the fluoride ion removal rate was 40.6%.

In summary: the present invention provides a method for treating waste lithium battery leachate and a method for recycling waste lithium battery. By calcining the iron and aluminum slag generated during the leachate treatment process at high temperature, the high-temperature calcined product is recycled as a Fenton-like catalyst. ; After adjusting the pH value of the leachate, it reacts with hydrogen peroxide and a Fenton-like catalyst to convert ferrous ions into ferric ions while allowing organic matter to react. At the same time, the porous characteristics of the Fenton-like catalyst can be used to adsorb fluoride ions in the leachate. Has the following advantages:

(1) Compared with the existing process, the present invention recycles iron and aluminum slag, greatly reducing the generation of solid waste and reducing environmental protection costs.

(2) Compared with the existing process, the product obtained by calcining iron-aluminum slag in the present invention has a high specific surface area, can also serve as a Fenton-like catalyst, and can be returned to the leaching process to remove COD and fluorine, reducing back-end impurity removal costs. , and no other waste is produced.

(3) Compared with the existing process, the present invention oxidizes ferrous ions with hydrogen peroxide and simultaneously undergoes Fenton catalytic reaction and adsorption of fluoride ions. There is no need to add other auxiliary materials and change reaction conditions. The three reactions are performed simultaneously, greatly shortening the time. process.

(4) Compared with the existing process, the present invention is based on an upgrade, retaining its original leaching function while improving the COD removal rate, adding a new fluorine removal function, and no other impurities are introduced.

The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims

A method for treating waste lithium battery leachate, which is characterized by including:

The leachate is subjected to a primary pH adjustment and then reacts with an oxidant and a Fenton-like catalyst. After the reaction, a secondary pH adjustment is performed, and the iron-aluminum slag and purified leachate are obtained after filtration;

Wherein, the preparation process of the Fenton-like catalyst includes: calcining the iron-aluminum slag at high temperature.
The method for treating waste lithium battery leachate according to claim 1, characterized in that the high-temperature calcination controls the calcination temperature to 800-1000°C and the calcination time to 4-6 hours; and the calcination process is carried out in an inert atmosphere;

Preferably, the calcination temperature is 900-1000°C and the calcination time is 4.5-5.5h.
The waste lithium battery leachate treatment method according to claim 2, characterized in that the product calcined at high temperature is pulverized, passed through a 100-200 mesh screen, and the sieved material is taken as the Fenton-like catalyst and added to the leachate;

Preferably, the oversize material continues to be returned for crushing.
The method for treating waste lithium battery leachate according to any one of claims 1-3, characterized in that the primary pH adjustment is to adjust the pH value to 2-4, and the secondary pH adjustment is to control the pH value. for 4-6.
The method for treating waste lithium battery leachate according to claim 4, characterized in that both the primary pH value adjustment and the secondary pH value adjustment are adjusted using a sodium carbonate solution with a mass fraction of 10%-30%.
The method for treating waste lithium battery leachate according to claim 4, wherein the reaction with the oxidant and the Fenton-like catalyst is to control the reaction temperature to be 60-90°C and the reaction time to be 60-120 min;

Preferably, the oxidizing agent is selected from at least one of hydrogen peroxide and manganese dioxide; more preferably, it is hydrogen peroxide;

Preferably, the stirring rate is controlled to 400-600 r/min during the reaction.
The method for treating waste lithium battery leachate according to claim 6, wherein the molar ratio of the added amount of hydrogen peroxide to the ferrous ions in the leachate is 1:1-2, and each liter of leachate corresponds to the Fenton-like catalyst. The added amount is 10-40g;

Preferably, the hydrogen peroxide is added at a flow rate of 0.5-1.5 mL/min.
The method for treating waste lithium battery leachate according to claim 7, characterized in that part of the iron-aluminum slag is calcined at high temperature, and the calcined product is used as the Fenton-like catalyst; and the remaining iron-aluminum slag is used as the Fenton-like catalyst; Recycled as building materials;

Preferably, the fluorine-containing tail gas generated during the high-temperature calcination process is treated by an absorption device and then discharged.
A method for recycling waste lithium batteries, which is characterized in that it includes the waste lithium battery leachate treatment method described in any one of claims 1-8;

Wherein, the leachate is obtained by acid leaching from waste lithium batteries.
The recycling method of used lithium batteries according to claim 9, characterized in that the acid leaching process includes: mixing used lithium batteries and sulfuric acid for leaching, and controlling the pH value of leaching to 0.5-1.