CN117303455A - A method for synthesizing cobalt blue using cobalt-aluminum solid-phase method in waste lithium batteries - Google Patents

Abstract

The invention provides a method for synthesizing cobalt blue by using a cobalt-aluminum solid phase method in waste lithium batteries, which comprises the steps of disassembling and crushing positive plates of the waste lithium batteries to obtain positive powder, then carrying out reduction acid leaching on the positive powder to obtain cobalt-aluminum mixed leaching solution, removing impurities and precipitating the cobalt-aluminum mixed leaching solution to obtain aluminum hydroxide and cobalt hydroxide, and finally carrying out mixed ball milling on the aluminum hydroxide and the cobalt hydroxide to obtain the cobalt blue. The invention recovers cobalt-aluminum metal resources from waste lithium ion batteries, synthesizes the cobalt-aluminum metal resources into cobalt blue products by adopting a solid phase method, and has the advantages of simple technical process and low production cost.

Description

A method for synthesizing cobalt blue using cobalt-aluminum solid-phase method in waste lithium batteries

Technical field

The invention belongs to the field of chemical engineering technology and relates to a method for synthesizing cobalt blue by utilizing cobalt-aluminum solid-phase method in waste lithium batteries.

Background technique

As the penetration rate of new energy vehicles accelerates, the demand for nickel and cobalt resources will further increase. By then, the main supply source of nickel and cobalt in the new energy industry will gradually shift from traditional mines to secondary resource recycling.

After a large number of power batteries are decommissioned, without proper disposal and maximum value utilization, they will threaten public safety, cause irreversible environmental pollution, and waste precious valuable metal resources. Wasted power batteries contain electrolytes, positive and negative current collectors, separators, casings, etc. Among them, the metal nickel, cobalt, copper, iron, aluminum, and lithium on the current collectors are all primary resources and are of great recycling value. Efficient recycling and reuse of cobalt, aluminum and other metals in used lithium batteries is an inevitable requirement for the healthy and sustainable development of the new energy industry.

Cobalt blue is a pigment with a spinel crystal structure, mainly composed of cobalt oxide (CoO) and aluminum oxide (Al2O3), also known as cobalt aluminate (CoAl2O4). The excellent performance of cobalt blue pigment is mainly reflected in two aspects: high thermal stability and high chemical stability. It is currently the most weather-resistant, light-resistant, heat-resistant, and chemical-resistant blue pigment in the world. It is suitable for applications where other blue pigments cannot meet the requirements. For harsh uses, such as ultra-durable engineering plastic products such as exterior ultra-durable coatings and building wall panels, it is mainly used as a colorant. Cobalt aluminum is recovered from used lithium batteries and recycled into the preparation of cobalt blue. It not only realizes the recycling and reuse of resources such as cobalt and aluminum in used lithium batteries, but also solves the problem of secondary pollution caused by used lithium batteries to the environment.

Contents of the invention

The object of the present invention is to provide a method for synthesizing cobalt blue using the cobalt-aluminum solid-phase method in waste lithium batteries in order to solve the problems existing in the prior art.

To this end, the present invention adopts the following technical solutions:

A method for synthesizing cobalt blue using cobalt-aluminum solid-phase method in waste lithium batteries, including the following steps:

(1) Disassemble and crush the used lithium battery cathode sheets to obtain cathode powder;

(2) Perform reducing acid leaching on the cathode powder to obtain a cobalt-aluminum mixed leachate;

(3) Adjust the pH value of the cobalt-aluminum mixed leachate and then precipitate in stages to obtain aluminum hydroxide and cobalt hydroxide;

(4) Dry and mix aluminum hydroxide and cobalt hydroxide to obtain a mixture. The molar ratio of cobalt ions and aluminum ions in the mixture is 2:1;

(5) Add mineralizer to the mixture and perform high-energy ball milling;

(6) The ball-milled mixture is calcined at high temperature, washed, dried and air-flow crushed to obtain cobalt blue.

Further, the waste lithium battery in step (1) is a waste lithium cobalt oxide battery.

Further, the cobalt content of the cathode powder in step (1) is 45-55%, and the aluminum content is 10-15%.

Further, the reducing agent for acid leaching in step (2) is hydrogen peroxide or sodium sulfite, and the leaching agent for acid leaching is any one of sulfuric acid, nitric acid or hydrochloric acid.

Further, sodium hydroxide or lithium hydroxide is used to adjust the pH value in step (3).

Further, in step (3), the pH of the cobalt-aluminum leach solution is first adjusted to 3.5-4.5, solid-liquid separation is performed to obtain aluminum hydroxide, and then the pH is adjusted to 10-11, and solid-liquid separation is performed to obtain cobalt hydroxide.

Further, in step (4), the aluminum hydroxide and cobalt hydroxide are dried at a temperature of 80-100°C.

Further, the mineralizing agent in step (5) is a NaCl--KCl system mineralizing agent.

Further, in step (6), the temperature is 1100-1300°C and the temperature is kept for 30-180 minutes.

The beneficial effects of the present invention are:

(1) Recover cobalt and aluminum metal resources from used lithium-ion batteries and synthesize them into cobalt blue products using the solid-phase method. It only needs to be calcined, washed, dried and crushed. It has the advantages of simple process and low production cost. .

(2) Recycling the cobalt and aluminum valuable metals in used lithium-ion batteries not only solves the problem of environmental pollution and waste of valuable metal resources after used lithium-ion batteries are scrapped and discarded, but also removes cobalt and aluminum from used lithium-ion batteries. The recycling and reuse of metal resources realizes the sustainable development of the new energy automobile industry.

Description of drawings

Figure 1 is a process flow diagram of the present invention.

Detailed ways

The present invention will be described in detail below in conjunction with the examples:

Example 1

The positive electrode sheets of the waste lithium battery are disassembled and crushed to obtain positive electrode powder. In this embodiment, the waste lithium battery is a waste lithium cobalt oxide battery. The cobalt content in the positive electrode powder is 52% and the aluminum content is 13%.

(2) The positive electrode powder is subjected to reducing acid leaching. The reducing agent is hydrogen peroxide or sodium sulfite. In this embodiment, hydrogen peroxide is used, and the leaching acid is sulfuric acid to obtain a cobalt-aluminum mixed leachate. The cobalt concentration in the cobalt-aluminum mixed leachate is 39g/L, and the aluminum The concentration is 7g/L, and the pH of the leach solution is 2.0.

(3) Adjust the pH value of the cobalt-aluminum mixed leachate and then precipitate in stages to obtain aluminum hydroxide and cobalt hydroxide. Specifically, add a 20-30% sodium hydroxide solution to the cobalt-aluminum mixed leachate to adjust the pH value. In the embodiment, a 25% sodium hydroxide solution is added to adjust the pH value to 4.5, and then solid-liquid separation is performed to obtain aluminum hydroxide solid. Then a 25% sodium hydroxide solution is added to the solution again to adjust the pH value to 10.8. Solid-liquid separation yields cobalt hydroxide solid.

(4) Dry aluminum hydroxide and cobalt hydroxide at a temperature of 100°C and then mix them to obtain a mixture. The molar ratio of cobalt ions and aluminum ions in the mixture is 2:1.

(5) Add a NaCl--KCl system mineralizer to the mixture, and then perform high-energy ball milling. Adding the mineralizer can reduce the degree of agglomeration of crystal grains in the mixture during the solid-phase synthesis process and improve the ball milling effect.

(6) The ball-milled mixture is calcined at high temperature at a temperature of 1200°C, and then kept for 120 minutes. The calcined mixture is washed with pure water at a solid-to-liquid ratio of 1:3. After washing, the temperature is 95°C. Drying in an environment, and finally using airflow crushing to obtain cobalt blue.

Example 2

The positive electrode sheets of the waste lithium battery are disassembled and crushed to obtain positive electrode powder. In this embodiment, the waste lithium battery is a waste lithium cobalt oxide battery. The cobalt content in the positive electrode powder is 49% and the aluminum content is 12%.

(2) The positive electrode powder is subjected to reducing acid leaching. The reducing agent is hydrogen peroxide or sodium sulfite. In this embodiment, hydrogen peroxide is used, and the leaching acid is sulfuric acid to obtain a cobalt-aluminum mixed leachate. The cobalt concentration in the cobalt-aluminum mixed leachate is 42g/L, and the aluminum The concentration is 8.3g/L, and the pH of the leach solution is 1.2.

(3) Adjust the pH value of the cobalt-aluminum mixed leachate and then precipitate in stages to obtain aluminum hydroxide and cobalt hydroxide. Specifically, add a 20-30% sodium hydroxide solution to the cobalt-aluminum mixed leachate to adjust the pH value. In the embodiment, a sodium hydroxide solution with a concentration of 30% is added to adjust the pH value to 4.0, and then solid-liquid separation is performed to obtain an aluminum hydroxide solid. Then a sodium hydroxide solution with a concentration of 25% is added to the solution again to adjust the pH value to 11. , solid-liquid separation yields cobalt hydroxide solid.

(4) Dry aluminum hydroxide and cobalt hydroxide at a temperature of 90°C and then mix them to obtain a mixture. The molar ratio of cobalt ions and aluminum ions in the mixture is 2:1.

(5) Add a NaCl--KCl system mineralizer to the mixture, and then perform high-energy ball milling. Adding the mineralizer can reduce the degree of agglomeration of crystal grains in the mixture during the solid-phase synthesis process and improve the ball milling effect.

(6) The ball-milled mixture is calcined at high temperature at a temperature of 1300°C, and then kept for 60 minutes. The calcined mixture is washed with pure water at a solid-to-liquid ratio of 1:4. After washing, the temperature is 100 It is dried in an environment of ℃, and finally crushed by airflow to obtain cobalt blue.

Claims (9)

1. The method for synthesizing cobalt blue by using the cobalt-aluminum solid phase method in the waste lithium battery is characterized by comprising the following steps of:

(1) Disassembling and crushing the waste lithium battery positive plate to obtain positive electrode powder;

(2) Reducing and acid leaching is carried out on the anode powder to obtain cobalt-aluminum mixed leaching liquid;

(3) Regulating the pH value of the cobalt-aluminum mixed leaching solution, and then carrying out fractional precipitation to obtain aluminum hydroxide and cobalt hydroxide;

(4) Drying and mixing aluminum hydroxide and cobalt hydroxide to obtain a mixture, wherein the molar ratio of cobalt ions to aluminum ions in the mixture is 2:1;

(5) Adding mineralizer into the mixture and performing high-energy ball milling;

(6) And (3) performing high-temperature calcination, washing, drying and air flow crushing on the mixture after ball milling to obtain cobalt blue.

2. The method for synthesizing cobalt blue by using cobalt aluminum solid phase method in waste lithium battery as claimed in claim 1, wherein the waste lithium battery in the step (1) is a waste lithium cobaltate battery.

3. The method for synthesizing cobalt blue by using the cobalt-aluminum solid phase method in the waste lithium battery as claimed in claim 1, wherein the cobalt content of the positive electrode powder in the step (1) is 45-55%, and the aluminum content is 10-15%.

4. The method for synthesizing cobalt blue by using the cobalt-aluminum solid phase method in the waste lithium battery as claimed in claim 1, wherein the reducing agent for reducing acid leaching in the step (2) is hydrogen peroxide or sodium sulfite, and the leaching agent for acid leaching is any one of sulfuric acid, nitric acid or hydrochloric acid.

5. The method for synthesizing cobalt blue by using cobalt aluminum solid phase method in waste lithium battery as claimed in claim 1, wherein sodium hydroxide or lithium hydroxide is adopted to adjust pH value in the step (3).

6. The method for synthesizing cobalt blue by utilizing the cobalt-aluminum solid phase method in the waste lithium battery as claimed in claim 1, wherein in the step (3), the pH of the cobalt-aluminum leaching solution is firstly adjusted to 3.5-4.5, aluminum hydroxide is obtained by solid-liquid separation, then the pH is adjusted to 10-11, and cobalt hydroxide is obtained by solid-liquid separation.

7. The method for synthesizing cobalt blue by using cobalt aluminum solid phase method in waste lithium battery as claimed in claim 1, wherein in the step (4), aluminum hydroxide and cobalt hydroxide are dried at 80-100 ℃.

8. The method for synthesizing cobalt blue by using a cobalt aluminum solid phase method in a waste lithium battery as claimed in claim 1, wherein the mineralizer in the step (5) is a NaCl-KCl system mineralizer.

9. The method for synthesizing cobalt blue by using the cobalt-aluminum solid phase method in the waste lithium battery as claimed in claim 1, wherein in the step (6), the cobalt blue is calcined at the temperature of 1100-1300 ℃ and the heat preservation time is 30-180min.