Method for recovering active metal of lithium secondary battery

Patent metadata

Field	Value
Publication number	US-2023250507-A1
Application number	US-202118010576-A
Country	US
Kind code	A1
Filing date	May 31, 2021
Priority date	Jun 18, 2020
Publication date	Aug 10, 2023
Grant date	—

Abstract

In a method for recovering an active metal of a lithium secondary battery, a sulfuric acid solution is added to a lithium metal composite oxide so as to prepare a sulfated active material solution. A transition metal is extracted from the sulfated active material solution. A lithium precursor is recovered by adding a lithium extracting agent to the solution remaining after the transition metal has been extracted from the sulfated active material solution. In the method, the amount of impurities is reduced, and sulfuric acid and the neutralizing agent can be recycled so that a high-yield lithium precursor recovery is enabled.

First claim

1 . A method for recovering an active metal of a lithium secondary battery, the method comprising:
adding sulfuric acid to a lithium metal composite oxide to prepare a sulfated active material solution; extracting a transition metal from the sulfated active material solution; and adding a lithium extracting agent to a residual solution in which the transition metal is extracted from the sulfated active material solution to recover a lithium precursor.

2 . The method according to claim 1 , wherein the extracting the transition metal comprises adding a transition metal extracting agent that includes an alkyl phosphate-based compound, an alkyl phosphonic acid-based compound, an alkyl phosphinic acid-based compound or a carboxylic acid-based compound into the sulfated active material solution.

3 . The method according to claim 2 , wherein the lithium metal composite oxide contains nickel, cobalt and manganese; and
the extracting the transition metal comprises sequentially increasing a pH of the sulfated active material solution and sequentially extracting manganese, cobalt and nickel.

4 . The method of claim 2 , wherein the lithium metal composite oxide contains nickel, cobalt, and manganese; and
the extracting the transition metal comprises simultaneously extracting nickel, cobalt, and manganese.

5 . The method of claim 2 , wherein the lithium extracting agent includes an alkyl phosphinic acid-based compound, an alkyl phosphonic acid-based compound or a carboxylic acid-based compound.

6 . The method of claim 5 , wherein the transition metal extracting agent and the lithium extracting agent are added in a saponified state by an alkali metal hydroxide.

7 . The method of claim 6 , wherein an alkali metal sulfate and lithium sulfate are generated from the residual solution by adding the lithium extracting agent.

8 . The method of claim 7 , further comprising converting the alkali metal sulfate generated from the residual solution into a sulfuric acid solution and an alkali metal hydroxide.

9 . The method according to claim 8 , further comprising recycling the converted alkali metal hydroxide to a saponification of the transition metal extracting agent and the lithium extracting agent.

10 . The method of claim 8 , further comprising recycling the converted sulfuric acid solution to preparing the sulfated active material solution or extracting the transition metal from the sulfated active material solution.

11 . The method of claim 8 , wherein converting the alkali metal sulfate generated from the residual solution into the sulfuric acid solution and the alkali metal hydroxide comprises an electrodialysis.

12 . The method according to claim 1 , wherein the lithium extracting agent is added to the residual solution to generate lithium sulfate; and
the recovering the lithium precursor comprises converting the generated lithium sulfate into lithium hydroxide by an electrodialysis.

13 . The method of claim 12 , wherein a sulfuric acid solution is generated together with lithium hydroxide by the electrodialysis.

14 . The method of claim 13 , further comprising recycling the sulfuric acid solution to preparing the sulfated active material solution or extracting the transition metal from the sulfated active material solution.

15 . A method for recovering an active metal of a lithium secondary battery, comprising:
adding sulfuric acid to a lithium metal composite oxide to prepare a sulfated active material solution; extracting a transition metal from the sulfated active material solution; and recovering lithium hydroxide directly from a residual solution from which the transition metal is extracted from the sulfated active material solution by an electrodialysis.

16 . The method of claim 15 , wherein the recovering lithium hydroxide comprises converting lithium sulfate contained in the residual solution into lithium hydroxide by the electrodialysis.

17 . The method according to claim 16 , further comprising recycling a sulfuric acid solution to preparing the sulfated active material solution or extracting the transition metal from the sulfated active material solution; and
the sulfuric acid solution is generated from lithium sulfate by the electrodialysis.

18 . The method of claim 15 , the extracting the transition metal comprises adding a transition metal extracting agent that includes an alkyl phosphate-based compound, an alkyl phosphonic acid-based compound, an alkyl phosphinic acid-based compound or a carboxylic acid-based compound into the sulfated active material solution.

19 . The method of claim 18 , wherein the lithium metal composite oxide contains nickel, cobalt and manganese; and
the extracting the transition metal comprises sequentially increasing a pH of the sulfated active material solution and sequentially extracting manganese, cobalt and nickel.

20 . The method of claim 18 , wherein the lithium metal composite oxide contains nickel, cobalt, and manganese; and
the extracting the transition metal comprises simultaneously extracting nickel, cobalt, and manganese.

21 . The method of claim 18 , further comprising recycling a portion of the recovered lithium hydroxide for a saponification of the transition metal extracting agent.

22 . (canceled)

Assignees

• Sk Innovation Co Ltd

Inventors

• Lee Hyeon Hui
• Park Ji Yun
• Seo Young Bin
• Lee Seung Ok
• Son Sung Real

Classifications

• B01D61/423

  comprising multiple electrodialysis steps · CPC title

• C22B26/12 Primary

  Obtaining lithium · CPC title

• C22B3/045

  Leaching using electrochemical processes · CPC title

• C22B3/08 Primary

  Sulfuric acid {, other sulfurated acids or salts thereof} · CPC title

• C22B3/22

  by physical processes, e.g. by filtration, by magnetic means {, or by thermal decomposition} (treatment or purification of solutions by liquid-liquid extraction C22B3/26) · CPC title