CN111115712A

CN111115712A - Method for decomposing lithium cobaltate

Info

Publication number: CN111115712A
Application number: CN201911348285.7A
Authority: CN
Inventors: 赵世福; 顾三奎; 刘怀意
Original assignee: Individual
Current assignee: Individual
Priority date: 2019-12-24
Filing date: 2019-12-24
Publication date: 2020-05-08

Abstract

The invention belongs to the technical field of lithium battery recycling, and particularly relates to a method for decomposing lithium cobaltate. A method of decomposing lithium cobaltate, comprising the steps of: (1) adding lithium cobaltate and urea into water, stirring uniformly, and slowly adding concentrated H₂SO₄Stirring at 80-90 deg.C for 4-5 hr, and filtering to obtain red filtrate and black residue; (2) adding solid sodium carbonate into the red filtrate obtained in the step (1), adjusting the pH value to 3.5-4.0, heating at 95-100 ℃ for 10-15min, filtering to obtain red filtrate and filter residue, and adding solid sodium carbonate into the red filtrate to adjust the pH value to 7.0-8.0 to obtain red cobalt carbonate precipitate and colorless filtrate; (3) and (3) adding solid sodium carbonate into the colorless filtrate obtained in the step (2) to adjust the pH value to 10.0-11.0, and obtaining white lithium carbonate precipitate. The method for decomposing lithium cobaltate provided by the invention is simple and convenient to operateEnvironment-friendly, and high recovery rate of cobalt and lithium.

Description

Method for decomposing lithium cobaltate

Technical Field

The invention belongs to the technical field of lithium battery recycling, and particularly relates to a method for decomposing lithium cobaltate.

Background

At present, more and more waste lithium batteries are available on the market, and the method for efficiently recovering lithium and cobalt in the waste lithium batteries has good environmental protection benefit and economic benefit. The lithium and cobalt in the waste lithium battery is lithium cobaltate (LiCoO)₂) In the form of (1), wherein the cobalt is trivalent cobalt, a suitable reducing agent must be added in the decomposition of the lithium cobaltate. Chinese patent application No. 201710569042.0 discloses the use of citric acid and thio-substituted carboxylic acidsThe method for recovering valuable metals from the anode materials of the waste lithium cobalt oxide batteries by using the sodium sulfate selects the sodium thiosulfate as the reducing agent, and the sodium thiosulfate as the reducing agent has the advantages of high reaction speed and high decomposition rate of lithium cobalt oxide, but has great defects: firstly, elemental sulfur and sulfur dioxide gas are generated in the reaction, so that the physical health is harmed, the production equipment is corroded, and the serious environmental protection problem is caused; second is cation Na of sodium thiosulfate⁺Sodium salt is generated after the reaction, and the separation and removal of the sodium salt need to generate corresponding cost and can influence the purity and recovery rate of lithium and cobalt products. Therefore, the existing method of decomposing lithium cobaltate needs further improvement.

Disclosure of Invention

The invention aims to provide a method for decomposing lithium cobaltate, which is simple and convenient to operate, environment-friendly and high in recovery rate.

Based on the purpose, the invention adopts the following technical scheme:

a method of decomposing lithium cobaltate, comprising the steps of:

(1) adding lithium cobaltate and urea into water, stirring uniformly, and slowly adding concentrated H₂SO₄Stirring at 80-90 deg.C for 4-5 hr, and filtering to obtain red filtrate and black residue;

(2) adding solid sodium carbonate into the red filtrate obtained in the step (1), adjusting the pH value to 3.5-4.0, heating at 95-100 ℃ for 10-15min, filtering to obtain red filtrate and filter residue, and adding solid sodium carbonate into the red filtrate to adjust the pH value to 7.0-8.0 to obtain red cobalt carbonate precipitate and colorless filtrate;

(3) and (3) adding solid sodium carbonate into the colorless filtrate obtained in the step (2) to adjust the pH value to 10.0-11.0, and obtaining white lithium carbonate precipitate.

Further, in the step (1), lithium cobaltate, urea, water and concentrated H₂SO₄The mass-volume ratio of the (B) is 20-90 g: 1-6 g: 100-800 ml: 10-80 ml.

Compared with the prior art, the invention has the following beneficial effects:

the method for decomposing lithium cobaltate provided by the invention uses urea as a reducing agent, and the reaction equation is as follows:

6LiCoO₂+ CO（NH₂）₂+ 9H₂SO₄= 6CoSO₄+ 3Li₂SO₄+ N₂+ 11H₂O + CO₂

as can be seen from the reaction equation, the redox reaction of urea, lithium cobaltate and sulfuric acid generates cobalt sulfate and lithium sulfate, and simultaneously generates nontoxic and harmless nitrogen gas, carbon dioxide gas and water. The method is simple and easy to implement, does not generate sulfur simple substance, sulfur dioxide gas and other harmful substances, is environment-friendly, reduces the addition amount of sodium salt in the production process, and saves the cost of subsequent sodium salt treatment.

According to the invention, the black residue in the step (1) is mainly carbon impurity, the pH of the red filtrate in the step (1) is adjusted to 3.5-4.0 by adding solid sodium carbonate, so that impurities such as iron, manganese, aluminum and the like can be removed, the pH of the red filtrate in the step (2) is adjusted to 7.0-8.0 by adding solid sodium carbonate again, red cobalt carbonate precipitate can be separated, finally, the pH of the colorless filtrate is adjusted to 10.0-11.0 by adding solid sodium carbonate, white lithium carbonate precipitate can be obtained, the difference of the pH values adjusted for three times is large, the cross precipitation phenomenon of two metals of cobalt and lithium can not occur, and the purity of cobalt carbonate and lithium carbonate is ensured. Through detection and calculation of an inductively coupled plasma spectrometer (ICP), the purity of the red cobalt carbonate precipitate is greater than 99%, the recovery rate of cobalt is greater than 98%, the purity of the white lithium carbonate precipitate is greater than 99%, and the recovery rate of lithium is greater than 98%.

Detailed Description

The technical solution of the present invention is described in further detail with reference to specific examples, but the present invention is not limited thereto.

Example 1

A method of decomposing lithium cobaltate, comprising the steps of:

(1) adding lithium cobaltate and urea into water, stirring uniformly, and slowly adding concentrated H₂SO₄Wherein lithium cobaltate, urea, water and concentrate are addedH₂SO₄The mass volume ratio of the red pigment to the black pigment is 20 g: 1 g: 100 ml: 10ml, and the red pigment is stirred for 4 hours at the temperature of 80 ℃ and then filtered to obtain red filtrate and black residue;

(2) adding solid sodium carbonate into the red filtrate obtained in the step (1), adjusting the pH value to 3.5, heating at 95 ℃ for 10min, filtering to obtain red filtrate and filter residue, and adding solid sodium carbonate into the red filtrate to adjust the pH value to 7.0 to obtain red cobalt carbonate precipitate and colorless filtrate;

(3) adding solid sodium carbonate into the colorless filtrate obtained in the step (2) to adjust the pH value to 10.0, and obtaining white lithium carbonate precipitate.

The purity of the cobalt carbonate detected by ICP was 99.18%, and the recovery of cobalt was 98.3%.

The purity of lithium carbonate detected by ICP was 99.13%, and the recovery of lithium was 98.5%.

Example 2

A method of decomposing lithium cobaltate, comprising the steps of:

(1) adding lithium cobaltate and urea into water, stirring uniformly, and slowly adding concentrated H₂SO₄Wherein lithium cobaltate, urea, water and concentrated H₂SO₄The mass volume ratio of the red pigment to the black pigment is 55g to 3.5g to 450ml to 45ml, and the mixture is stirred for 4.5 hours at the temperature of 85 ℃ and then filtered to obtain red filtrate and black residue;

(2) adding solid sodium carbonate into the red filtrate obtained in the step (1), adjusting the pH value to 3.8, heating at 98 ℃ for 13min, filtering to obtain red filtrate and filter residue, and adding solid sodium carbonate into the red filtrate to adjust the pH value to 7.5 to obtain red cobalt carbonate precipitate and colorless filtrate;

(3) and (3) adding solid sodium carbonate into the colorless filtrate obtained in the step (2) to adjust the pH to 10.5, and obtaining white lithium carbonate precipitate.

The purity of the cobalt carbonate is 99.26 percent by adopting ICP detection, and the recovery rate of the cobalt is 98.6 percent.

The purity of lithium carbonate detected by ICP was 99.14%, and the recovery of lithium was 98.8%.

Example 3

A method of decomposing lithium cobaltate, comprising the steps of:

(1) adding lithium cobaltate and urea into water, stirring uniformly, and slowly adding concentrated H₂SO₄Wherein lithium cobaltate, urea, water and concentrated H₂SO₄The mass volume ratio of the red pigment to the black pigment is 90g to 6g to 800ml to 80ml, and the red pigment is stirred for 5 hours at the temperature of 90 ℃ and then filtered to obtain red filtrate and black residue;

(2) adding solid sodium carbonate into the red filtrate obtained in the step (1), adjusting the pH value to 4.0, heating for 15min at 100 ℃, filtering to obtain red filtrate and filter residue, and adding solid sodium carbonate into the red filtrate to adjust the pH value to 8.0 to obtain red cobalt carbonate precipitate and colorless filtrate;

(3) adding solid sodium carbonate into the colorless filtrate obtained in the step (2) to adjust the pH value to 11.0, and obtaining white lithium carbonate precipitate.

The purity of the cobalt carbonate detected by ICP was 99.31%, and the recovery rate of cobalt was 98.8%.

The purity of lithium carbonate was 99.43% by ICP analysis, and the recovery of lithium was 98.3%.

Claims

1. A method of decomposing lithium cobaltate, comprising the steps of:

2. The method of decomposing lithium cobaltate according to claim 1, wherein the lithium cobaltate, urea, water and concentrated H in the step (1)₂SO₄The mass-volume ratio of the components is 20-90 g: 1-6 g: 100-800ml∶10-80ml。