US-20260125776-A1 - METHOD FOR RECOVERING ACTIVE METAL OF LITHIUM SECONDARY BATTERY

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.

Inventors

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

Assignees

• SK INNOVATION CO., LTD.

Dates

Publication Date

20260507

Application Date

20260106

Priority Date

20200618

Claims (20)

1. 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 comprising lithium and a transition metal comprising nickel, cobalt, and manganese to prepare a sulfated active material solution; extracting the 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, wherein the residual solution is free from a divalent ion.
2. 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. 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. 4 . The method of claim 2 , wherein the extracting the transition metal comprises simultaneously extracting nickel, cobalt, and manganese in a single extraction process.
5. 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. 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. 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. 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. 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. 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. 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. 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. 13 . The method of claim 12 , wherein a sulfuric acid solution is generated together with lithium hydroxide by the electrodialysis.
14. 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. 15 . A method for recovering an active metal of a lithium secondary battery, comprising: adding sulfuric acid to a lithium metal composite oxide comprising lithium and a transition metal comprising nickel, cobalt and manganese to prepare a sulfated active material solution; extracting a transition metal from the sulfated active material solution, wherein the extracting comprising (i) sequentially increasing a pH of the sulfated active material solution and sequentially extracting the manganese, the cobalt and the nickel in this order, or (ii) extracting simultaneously the nickel, the cobalt, and the manganese in a single extraction process; 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. 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. 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. 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. 19 . The method of claim 18 , wherein the extracting the transition metal comprises sequentially increasing a pH of the sulfated active material solution and sequentially extracting the manganese, the cobalt and the nickel in this order.
20. 20 . The method of claim 18 , wherein the lithium metal composite oxide contains nickel, cobalt, and manganese; and the extracting of the transition metal comprises simultaneously extracting the nickel, the cobalt, and the manganese in the single extraction process.

Description

CROSS REFERENCE TO RELATED APPLICATIONS AND CLAIM OF PRIORITY This application is a continuation application of U.S. application Ser. No. 18/010,576 filed on Dec. 15, 2022, which is a National Phase application under 35 U.S.C. § 371 of International Application No. PCT/KR2021/006733, filed on May 31, 2021, which claims priority to the benefit of Korean Patent Application No. 10-2020-0074235 filed in the Korean Intellectual Property Office on Jun. 18, 2020, the entire contents of which are incorporated herein by reference. BACKGROUND 1. Technical Field The present invention relates to a method for recovering an active metal of a lithium secondary battery. More particularly, the present invention relates to a method for recovering an active metal of a lithium secondary battery utilizing an acidic solution and a basic solution. 2. Background Art Recently, a secondary battery has been widely employed as a power source of a mobile electronic device such as a camcorder, a mobile phone, a laptop computer, etc., and a vehicle such as an electric vehicle, a hybrid vehicle, etc. A lithium secondary battery is highlighted among the secondary battery due to advantages such as high operational voltage and energy density per unit weight, a high charging rate, a compact dimension, etc. A lithium metal oxide may be used as an active material for a cathode of the lithium secondary battery. The lithium metal oxide may further contain a transition metal such as nickel, cobalt, manganese, etc. As the above-mentioned high-cost valuable metals are used for the cathode active material, 20% or more of a production manufacturing cost is required for manufacturing the cathode material. Additionally, as environment protection issues have recently been highlighted, a recycling method of the cathode active material is being researched. For example, a method of sequentially recovering the valuable metals by leaching a waste cathode active material in a strong acid has been used. However, the wet process may be disadvantageous in aspect of a regeneration selectivity due to by-products caused by a solution-based reaction. Further, a large amount of the solution is used to degrade a process efficiency and a lithium recovery ratio, and thus sufficient recycle properties may not be provided. For example, Korean Registered Patent Publication No. 10-0709268 discloses an apparatus and a method for recycling a waste manganese battery and an alkaline battery. SUMMARY According to an aspect of the present invention, there is provided a method of recovering an active metal of a lithium secondary battery with improved reaction efficiency and process reliability. In a method for recovering an active metal of a lithium secondary battery according to embodiments of the present invention, sulfuric acid is added to a lithium metal composite oxide to prepare a sulfated active material solution. A transition metal is extracted from the sulfated active material solution. A lithium extracting agent is added to a residual solution in which the transition metal is extracted from the sulfated active material solution to recover a lithium precursor. In some embodiments, 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 may be added into the sulfated active material solution to extract the transition metal. In some embodiments, the lithium metal composite oxide may contain nickel, cobalt and manganese. A pH of the sulfated active material solution may be sequentially increased to sequentially extract manganese, cobalt and nickel. In some embodiments, the lithium metal composite oxide may contain nickel, cobalt, and manganese, and nickel, cobalt, and manganese may be simultaneously extracted. In some embodiments, the lithium extracting agent may include an alkyl phosphinic acid-based compound, an alkyl phosphonic acid-based compound or a carboxylic acid-based compound. In some embodiments, the transition metal extracting agent and the lithium extracting agent may be added in a saponified state by an alkali metal hydroxide. In some embodiments, an alkali metal sulfate and lithium sulfate may be generated from the residual solution by adding the lithium extracting agent. In some embodiments, the alkali metal sulfate generated from the residual solution may be converted into a sulfuric acid solution and an alkali metal hydroxide. In some embodiments, the converted alkali metal hydroxide may be recycled to a saponification of the transition metal extracting agent and the lithium extracting agent. In some embodiments, the converted sulfuric acid solution may be recycled to the preparation of the sulfated active material solution or the extraction of the transition metal from the sulfated active material solution. In some embodiments, the conversion of the alkali metal sulfate generated from the residual solution into th