CN117089705B

CN117089705B - A method for recycling waste lithium battery materials

Info

Publication number: CN117089705B
Application number: CN202310948316.2A
Authority: CN
Inventors: 甄爱钢; 凌怊; 刘元龙; 付贤家; 周新胜; 崔星星; 郝茂德; 赵美平; 吴心平; 祝俊健; 李娜; 朱美玲
Original assignee: Jiangsu Tianneng New Material Co ltd; Zhejiang Tianneng New Material Co ltd
Current assignee: Jiangsu Tianneng New Material Co ltd; Zhejiang Tianneng New Material Co ltd
Priority date: 2023-07-31
Filing date: 2023-07-31
Publication date: 2025-07-08
Anticipated expiration: 2043-07-31
Also published as: CN117089705A

Abstract

本发明公开一种废旧锂电池材料的回收方法，包括如下步骤：S1.将电池黑粉料采用酸浸提；S2.加入铁粉除铜；S3.加入氧化剂；S4.加入萃取剂A，萃取钙、锌后得到萃余液；S5.向S4所得的萃余液中加入萃取剂P507，萃取钴、镍，得到含有锰、镁、锂的萃余液；S6.向S5所得的萃余液中加入萃取剂Cy‑272，萃取镍、镁，得到含有锂的萃余液；S7.向S6所得的萃余液中加入液碱，压滤，浓缩、结晶，离心分离出无水硫酸钠和离心母液；离心母液降温、过滤，向滤液中加入纯碱，得到粗制碳酸锂，经过水洗、浆化，注入二氧化碳，生成碳酸氢锂溶液，最终形成碳酸锂。本发明能够平衡金属锂的回收率和回收纯度，在回收率达到90%以上，纯度可以达到98%以上。The invention discloses a method for recycling waste lithium battery materials, comprising the following steps: S1. acid leaching the battery black powder; S2. adding iron powder to remove copper; S3. adding an oxidant; S4. adding an extractant A to extract calcium and zinc to obtain a raffinate; S5. adding an extractant P507 to the raffinate obtained by S4, extracting cobalt and nickel, and obtaining a raffinate containing manganese, magnesium and lithium; S6. adding an extractant Cy-272 to the raffinate obtained by S5, extracting nickel and magnesium, and obtaining a raffinate containing lithium; S7. adding liquid alkali to the raffinate obtained by S6, filter pressing, concentrating, crystallizing, and centrifuging to separate anhydrous sodium sulfate and centrifugal mother liquor; cooling and filtering the centrifugal mother liquor, adding soda ash to the filtrate, obtaining crude lithium carbonate, washing, pulping, injecting carbon dioxide, generating lithium bicarbonate solution, and finally forming lithium carbonate. The present invention can balance the recovery rate and recovery purity of metallic lithium, and the purity can reach more than 98% when the recovery rate reaches more than 90%.

Description

Recovery method of waste lithium battery material

Technical Field

The invention relates to the technical field of lithium ion batteries, in particular to a method for recycling waste lithium battery materials.

Background

The lithium battery is a battery using lithium metal or lithium alloy as a positive electrode material and nonaqueous electrolyte solution, and has the advantages of high voltage, light weight, large specific energy, small self discharge, long cycle life, no memory effect, wide working temperature range, less environmental pollution and the like, thus rapidly occupying the secondary battery market and gradually replacing the traditional rechargeable battery. With the rapid development of mobile portable devices, especially the rapid development of new energy automobiles in recent years, the application range of lithium ion batteries is becoming more and more common, and the use amount is increasing year by year.

In the use process of the lithium battery, when the battery capacity is reduced to 80% of the initial capacity, the service life is reached, and the battery is scrapped. In order to reduce resource waste, waste lithium batteries are recycled, and the lithium batteries mainly comprise anode materials, cathode materials, electrolyte, diaphragms and the like, and precious metal resources in the lithium batteries are mainly concentrated on the anode materials. The positive electrode material mainly contains metal resources such as cobalt, nickel, copper, lithium and the like. At present, the recovery flow of the waste lithium battery anode material is generally to mechanically treat the battery monomer first and then to treat the anode plate by a wet method to obtain valuable metals.

The current recovery process firstly extracts metal resources such as nickel, cobalt, manganese and the like, then finally extracts lithium metal resources in a carbonate precipitation mode, the last lithium extraction process inevitably causes loss of the metal lithium resources in the recovery process, the recovery rate of lithium is obviously reduced, and on the other hand, the purity of nickel and cobalt salts obtained by extraction cannot reach the standard of battery level because a large amount of lithium ions exist in the leaching, extraction and back extraction processes, and the nickel and cobalt salts are difficult to recycle to the remanufacturing of lithium ion batteries.

Thus, many researches focus on the preferential extraction of lithium, such as a method for preferentially extracting metallic lithium from waste ternary lithium ion batteries and simultaneously obtaining battery-grade metallic salts disclosed in the applicant's prior invention patent CN113444885A, by roasting and reducing waste battery black powder in a hydrogen atmosphere and then leaching with pure water, the goal of preferentially extracting metallic lithium resources is achieved, and the recovery rate of metallic lithium is effectively improved.

However, the metal elements in the positive plate are more in variety, and different metal elements are mutually interfered, so that the recovery purity of lithium is limited.

Disclosure of Invention

The invention aims to provide a recovery method of waste lithium battery materials, which can balance the recovery rate and recovery purity of metal lithium, wherein the recovery rate is more than 90%, and the purity is more than 98%.

The invention provides a method for recycling waste lithium battery materials, which comprises the following steps:

S1, adding water into black powder of a battery to form slurry, adding low-concentration sulfuric acid and a first reducing agent, regulating the pH to 1.0-2.5, controlling the temperature to be 45-55 ℃, adding high-concentration sulfuric acid and a second reducing agent after reacting for a period of time, controlling the reaction temperature to be more than 80 ℃, obtaining reaction solution A after reacting for a period of time, press-filtering the reaction solution A, and collecting filtrate A;

S2, adding iron powder into the filtrate A obtained in the step S1, and filtering to remove copper in the filtrate to obtain filtrate B;

s3, adding an oxidant into the filtrate B obtained in the step S2, heating to above 85 ℃, adjusting the pH to 4.0-4.5, reacting to obtain a reaction liquid B, press-filtering the reaction liquid B, and collecting a filtrate C;

S4, adding an extractant A into the filtrate C to extract calcium and zinc to obtain raffinate containing manganese, cobalt, nickel, magnesium and lithium, wherein the extractant A is a mixture of Cy-302 and P204, and the extraction condition is pH1.5-2.5 and the temperature is 25-35 ℃;

S5, adding an extractant P507 into the raffinate obtained in the step S4 to extract cobalt and nickel to obtain raffinate containing manganese, magnesium and lithium, wherein the extraction conditions are that the pH value is 2.0-3.5;

s6, adding an extractant Cy-272 into the raffinate obtained in the step S5 to extract nickel and magnesium to obtain a raffinate containing lithium, wherein the extraction conditions are that the pH is 9.0-9.5 and the extraction temperature is 20-40 ℃;

s7, adding liquid alkali into the raffinate obtained in the step S6, maintaining the pH value to 9.0-10.0, and performing filter pressing to obtain filtrate D;

s8, concentrating and crystallizing the filtrate D obtained in the step S7, and centrifugally separating anhydrous sodium sulfate and centrifugal mother liquor;

s9, cooling and filtering the centrifugal mother liquor obtained in the step S8, and adding sodium carbonate into the filtrate to obtain crude lithium carbonate;

S10, washing and slurrying the crude lithium carbonate obtained in the step S9, injecting carbon dioxide to generate a lithium bicarbonate solution, filtering and separating insoluble substances, and performing impurity removal on the lithium bicarbonate solution, and heating the solution to form lithium carbonate.

Preferably, the first reducing agent is ascorbic acid and the second reducing agent is sodium thiosulfate.

Preferably, the second reducing agent is added in an amount greater than the first reducing agent.

Preferably, in step S1, the concentration of the low concentration sulfuric acid is 70% to 85%, and the concentration of the high concentration sulfuric acid is 95% to 98%.

Preferably, in step S1, after the filter residue after press filtration is pulped, sulfuric acid and a reducing agent are added, the pH is adjusted to 1.0-2.5, the reaction temperature is controlled to be higher than 80 ℃, a reaction solution A1 is obtained, and the reaction solution A1 is subjected to operations S2 to S10.

Preferably, in step S4, the mass ratio of Cy-302 to P204 is 3:1-1.5.

Preferably, in step S1, after the addition of the second reducing agent, the leaching temperature is controlled between 85 ℃ and 90 ℃.

Preferably, in step S1, the reaction time of adding the first reducing agent is 0.5h to 1.2h.

Preferably, in step S1, the reaction time for adding the second reducing agent is 1h to 1.5h.

Preferably, the extractants Cy-302, P204, P507, and Cy-272 are subjected to saponification treatment prior to use.

By implementing the technical scheme, the invention has the following beneficial effects:

1. The invention optimizes the ion separation process, recovers copper, (calcium, zinc), cobalt, nickel, magnesium and lithium successively, can reduce the mutual interference among metal ions, and overcomes the influence of the mutual interference on the ion recovery rate and the recovery purity.

2. When the battery slurry is leached, two reducing agents are sequentially added, metal ions are reduced in sections, the first reducing agent has strong reducibility, the metal ions are rapidly reduced at a lower temperature, the second reducing agent has weak reducibility, the metal ions are fully reduced at a higher temperature, and the leaching rate of the metal ions can be remarkably improved by matching the first reducing agent with the second reducing agent.

3. The invention optimizes the sulfuric acid concentration and the reducing agent used for leaching, so that various advantages of the reducing agent of the sulfuric acid concentration and the reducing agent are fully exerted, and the leaching rate of metal ions is improved.

4. The invention optimizes the extractant, in particular to the extractant A for extracting calcium and zinc, adopts a composite extractant and optimizes the extraction condition, can improve the relative specificity of extraction, can realize high extraction rate, improve extraction efficiency and reduce the loss of other ions under a smaller extraction stage number.

Detailed Description

The technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with specific embodiments, and it is apparent that the described embodiments are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

Along with the rapid development of new energy automobiles in recent years, the application range of lithium ion batteries is becoming more and more common, the use amount is increasing year by year, and the recycling of waste lithium batteries is the most effective means for recycling the waste lithium batteries.

The method for recycling the waste lithium batteries mainly comprises two parts, wherein the first part is finished in a dry workshop and comprises the steps of sorting, discharging, disassembling, crushing and the like of raw materials of the waste lithium batteries, and the second part is finished in a wet workshop and comprises the working procedures of batching, leaching, extracting and the like.

First part

1. Cascade utilization of waste lithium batteries

Sorting batteries in a waste lithium battery raw material echelon utilization workshop, recharging and selling the batteries which meet the echelon utilization requirement after detection, and enabling the waste batteries which do not meet the echelon utilization requirement to enter a subsequent discharging process.

2. Discharge of electric power

Before the disassembly and separation of the waste lithium ion batteries, discharge pretreatment is generally performed based on safety requirements, and a common method is to place the waste lithium ion batteries in a salt solution (such as Na ₂SO₄ solution) for about one week.

3. Disassembling, mechanical crushing and sorting

The discharged lithium ion battery enters a mechanical crushing procedure through a Z-type belt conveyor, the lithium ion battery is crushed through multi-stage crushing equipment, the crushing granularity is 5-10 mm, materials are screened into different granularities through vibration screening, the materials with different granularities are respectively subjected to a combined sorting procedure, plastics and battery shells are sorted out, and the rest materials enter the next procedure. Dust generated in the process is collected intensively and treated.

4. Pyrolysis of

The materials subjected to the mechanical crushing and sorting process enter a pyrolysis furnace through a full-automatic feeding system to be pyrolyzed, and the pyrolyzed materials enter the next process.

5. Multistage sorting

And the pyrolyzed material is easy to fall off due to the removal of the binder, the current collector and the anode powder and the cathode powder can be separated out by vibration separation, copper and aluminum are separated by specific gravity separation, and the black powder of the battery is obtained and enters a wet workshop for subsequent treatment.

The second part will be described in detail in the following examples.

Example 1

A method for recycling waste lithium battery materials comprises the following steps:

S1, adding 7L of water into 2kg of the battery black powder obtained by the first part treatment to form slurry, adding 15mol of sulfuric acid with the mass concentration of 70% and 1kg of ascorbic acid, regulating the pH value to 2.0, controlling the temperature to 50 ℃, reacting for 1h, adding 1.5kg of sodium thiosulfate and 15mol of sulfuric acid with the mass concentration of 95%, controlling the reaction temperature to 85 ℃, reacting for 1.5h to obtain a reaction solution A, press-filtering the reaction solution A, and collecting filtrate A;

S2, adding iron powder into the filtrate A obtained in the step S1, and filtering to remove copper in the filtrate, wherein the copper element removal rate is about 94% to obtain filtrate B;

S3, adding hydrogen peroxide into the filtrate B obtained in the step S2, oxidizing Fe ²⁺ in the solution into Fe ³⁺, heating to 90 ℃, adding sodium carbonate to adjust the pH to 4.0, reacting to obtain a reaction solution B, hydrolyzing Fe ³⁺ and Al ³⁺ in the solution into slag, press-filtering the reaction solution B, and collecting filtrate C;

S4, adding an extractant A subjected to 32% liquid alkali saponification treatment into filtrate C, carrying out 2-stage serial countercurrent extraction on the filtrate C, extracting calcium and zinc to obtain raffinate containing manganese, cobalt, nickel, magnesium and lithium, wherein the extractant A is a mixture of Cy-302 and P204 (the mass ratio is 3:1), the extraction condition is pH1.5 and the temperature is 25 ℃, and carrying out back extraction on an organic phase by adopting sulfuric acid with the concentration of 1mol/L to obtain calcium and zinc solution, so that the recovery of the calcium and the zinc is realized (the recovery rate reaches 96 percent);

S5, concentrating the raffinate obtained in the step S4, adding an extractant P507 subjected to 32% liquid alkali saponification treatment, carrying out 2-stage serial countercurrent extraction on the raffinate, and extracting cobalt and nickel to obtain raffinate containing manganese, magnesium and lithium, wherein the extraction condition is that pH is 2.0;

s6, adding an extractant Cy-272 subjected to 32% liquid alkali saponification treatment into the raffinate obtained in the step S5, carrying out 2-stage serial countercurrent extraction on the raffinate, extracting nickel and magnesium to obtain a raffinate containing lithium, wherein the extraction condition is that the pH value is 9.0, the extraction temperature is 25 ℃, and the organic phase is subjected to back extraction by adopting sulfuric acid with the concentration of 1mol/L to obtain cobalt and nickel solution, so that nickel and magnesium are recovered (the recovery rate of cobalt, nickel and magnesium reaches 95 percent);

s7, adding liquid alkali into the raffinate obtained in the step S6, maintaining the pH value to 9.0, and performing filter pressing to obtain filtrate D;

S10, washing and slurrying the crude lithium carbonate obtained in the step S9, injecting carbon dioxide to generate a lithium bicarbonate solution, filtering and separating insoluble substances, and performing impurity removal on the lithium bicarbonate solution, and heating the solution to form lithium carbonate. The recovery rate of lithium reaches 92%, and the purity can reach 98.6%.

Example 2

S1, adding 15L of water into 4kg of the battery black powder obtained by the first part treatment to form slurry, adding 15mol of sulfuric acid with the mass concentration of 75% and 2kg of ascorbic acid, regulating the pH to 2.0, controlling the temperature to 55 ℃, reacting for 1.5h, adding 3kg of sodium thiosulfate and 15mol of sulfuric acid with the mass concentration of 98%, controlling the reaction temperature to 90 ℃, reacting for 2h to obtain a reaction solution A, press-filtering the reaction solution A, and collecting filtrate A;

s2, adding iron powder into the filtrate A obtained in the step S1, and filtering to remove copper in the filtrate, wherein the copper element removal rate is about 96% to obtain filtrate B;

S3, adding hydrogen peroxide into the filtrate B obtained in the step S2, oxidizing Fe ²⁺ in the solution into Fe ³⁺, heating to 90 ℃, adding sodium carbonate to adjust the pH to 4.2, reacting to obtain a reaction solution B, hydrolyzing Fe ³⁺ and Al ³⁺ in the solution into slag, press-filtering the reaction solution B, and collecting filtrate C;

S4, adding an extractant A into the filtrate C, carrying out 2-stage serial countercurrent extraction on the solution, extracting calcium and zinc to obtain raffinate containing manganese, cobalt, nickel, magnesium and lithium, wherein the extractant A is a mixture of Cy-302 and P204 (the mass ratio is 3:1.5), the extraction condition is pH2.0, the temperature is 25 ℃, and the organic phase is subjected to back extraction by sulfuric acid with the concentration of 1mol/L to obtain calcium and zinc solution, so that the recovery of the calcium and the zinc is realized (the recovery rate reaches 96 percent);

s5, concentrating the raffinate obtained in the step S4, adding an extractant P507, carrying out 3-stage serial countercurrent extraction on the raffinate, and extracting cobalt and nickel to obtain raffinate containing manganese, magnesium and lithium, wherein the extraction condition is that the pH value is 2.0;

S6, adding an extractant Cy-272 into the raffinate obtained in the step S5, carrying out 3-stage serial countercurrent extraction on the raffinate, extracting nickel and magnesium to obtain a raffinate containing lithium, wherein the extraction conditions are that the pH value is 9.0, the extraction temperature is 25 ℃, and the organic phase is subjected to back extraction by adopting sulfuric acid with the concentration of 1mol/L to obtain cobalt and nickel solution, so that the recovery of nickel and magnesium is realized (the recovery rate of cobalt, nickel and magnesium reaches 94 percent);

s10, washing and slurrying the crude lithium carbonate obtained in the step S9, injecting carbon dioxide to generate a lithium bicarbonate solution, filtering and separating insoluble substances, and performing impurity removal on the lithium bicarbonate solution, and heating the solution to form lithium carbonate. The recovery rate of lithium reaches 93%, and the purity can reach 98.2%.

Example 3

In the present example, in step S1, the filter residue after press filtration was slurried, 98% sulfuric acid and sodium thiosulfate as a reducing agent were added, the pH was adjusted to 15, the reaction temperature was controlled to 90 ℃ to obtain a reaction solution A1, and the reaction solution A1 was mixed with the reaction solution a to perform the operations of S2 to S10.

The recovery rate of the obtained lithium reaches 93 percent, and the purity can reach 98.4 percent.

Example 4

Unlike example 1, in step S4, the extractant A is a mixture of Cy-302, P204 and ethylene oxide (mass ratio of 3:1:0.1). The recovery rate of the finally obtained lithium reaches 95%, and the purity can reach 99.2%.

Comparative example 1:

Unlike example 1, the operation of step S1 is different, in this comparative example S1, 2kg of the battery black powder obtained by the first partial treatment is slurried by adding 7L of water, 30mol of sulfuric acid with a mass concentration of 95% and 2.5kg of sodium thiosulfate are added, the reaction temperature is controlled at 85 ℃, the reaction is carried out for 1.5 hours, a reaction solution A is obtained, the reaction solution A is press-filtered, and the filtrate A is collected.

The recovery rate of the finally obtained lithium reaches 90%, and the purity can reach 97.1%.

Comparative example 2:

the difference from example 1 is that in this comparative example S1, sodium thiosulfate was used for both the first reducing agent and the second reducing agent.

The recovery rate of the finally obtained lithium reaches 82 percent, and the purity can reach 97.2 percent.

Comparative example 3:

the difference from example 1 is that in this comparative example S1, ascorbic acid was used for both the first reducing agent and the second reducing agent.

The recovery rate of the finally obtained lithium reaches 78%, and the purity can reach 97.2%.

Comparative example 4:

The difference from example 1 is that S1, 2kg of the battery black powder obtained by the first part treatment is added with 7L of water to form slurry, 15mol of sulfuric acid with the mass concentration of 95% and 1kg of ascorbic acid are added, the pH is regulated to 2.0, the temperature is controlled to be 85 ℃, after 1h of reaction, 15mol of sulfuric acid with the mass concentration of 95% and 1.5kg of sodium thiosulfate are added, the reaction temperature is controlled to be 85 ℃, after 1.5h of reaction, a reaction solution A is obtained, the reaction solution A is subjected to pressure filtration, and the filtrate A is collected.

The recovery rate of the finally obtained lithium reaches 75%, and the purity can reach 96.6%.

Comparative example 5:

The difference from example 1 is that in step S4, extractant A is Cy-302. The recovery rate of lithium reaches 88%, and the purity can reach 92.4%.

Comparative example 6:

Unlike example 1, in step S4, the extractant a is P204. The recovery rate of lithium reaches 86%, and the purity can reach 90.1%.

Comparative example 7:

Unlike example 1, in step S4, the extraction agent A was a mixture of Cy-302 and P204 (mass ratio of 1:3), the recovery rate of lithium was 82%, and the purity was 91.4%.

Claims

1. The method for recycling the waste lithium battery material is characterized by comprising the following steps of:

S1, adding water into black powder of a battery to form slurry, adding low-concentration sulfuric acid and a first reducing agent, regulating the pH to 1.0-2.5, controlling the temperature to 45-55 ℃, adding high-concentration sulfuric acid and a second reducing agent after a period of reaction, controlling the reaction temperature to be more than 80 ℃, and obtaining a reaction solution A after a period of reaction, and performing filter pressing on the reaction solution A to collect filtrate A;

S4, adding an extractant A into the filtrate C to extract calcium and zinc to obtain raffinate containing manganese, cobalt, nickel, magnesium and lithium, wherein the extractant A is a mixture of Cy-302 and P204, the extraction condition is pH1.5-2.5, and the temperature is 25-35 ℃, and in the step S4, the configuration mass ratio of Cy-302 to P204 is 3:1-1.5;

S10, washing and slurrying the crude lithium carbonate obtained in the step S9 with water, injecting carbon dioxide into the slurry to generate a lithium bicarbonate solution, filtering and separating insoluble substances, and enabling the lithium bicarbonate solution after impurity removal to enter a pyrolysis process, and heating the solution to form lithium carbonate.

2. The method for recycling waste lithium battery materials according to claim 1, wherein the addition amount of the second reducing agent is larger than the addition amount of the first reducing agent.

3. The method for recycling waste lithium battery materials according to claim 1, wherein in the step S1, the concentration of the low concentration sulfuric acid is 70% to 85%, and the concentration of the high concentration sulfuric acid is 95% to 98%.

4. The method for recycling waste lithium battery materials according to claim 1, wherein in the step S1, sulfuric acid and a reducing agent are added after filter residues are pulpified, the pH is adjusted to 1.0-2.5, the reaction temperature is controlled to be higher than 80 ℃, a reaction solution A1 is obtained, and the reaction solution A1 is subjected to operations from S2 to S10.

5. The method for recycling waste lithium battery materials according to claim 1, wherein in step S1, after adding the second reducing agent, the leaching temperature is controlled to be 85 ℃ to 90 ℃.

6. The method for recycling waste lithium battery materials according to claim 1, wherein in the step S1, the reaction time of adding the first reducing agent is 0.5h to 1.2h.

7. The method for recycling waste lithium battery materials according to claim 1, wherein in the step S1, the reaction time of adding the second reducing agent is 1h to 1.5h.

8. The method for recycling waste lithium battery materials according to claim 1, wherein the extracting agents Cy-302, P204, P507, cy-272 are subjected to saponification treatment before use.