US 12,304,826 B2
Method for producing lithium iron phosphate precursor by using retired lithium iron phosphate battery as raw material
Yongshou Lin, Ningde (CN); Guobao Wang, Ningde (CN); Ke Wang, Ningde (CN); Jiang Liu, Ningde (CN); and Bin Yao, Ningde (CN)
Assigned to CONTEMPORARY AMPEREX TECHNOLOGY (HONG KONG) LIMITED, Hong Kong (CN)
Filed by CONTEMPORARY AMPEREX TECHNOLOGY (HONG KONG) LIMITED, Hong Kong (CN)
Filed on Mar. 16, 2022, as Appl. No. 17/655,092.
Application 17/655,092 is a continuation of application No. PCT/CN2019/121728, filed on Nov. 28, 2019.
Prior Publication US 2022/0204355 A1, Jun. 30, 2022
Int. Cl. C01D 15/08 (2006.01); C01B 25/37 (2006.01); C25C 1/12 (2006.01); H01M 4/58 (2010.01); H01M 10/0525 (2010.01); H01M 10/54 (2006.01)
CPC C01D 15/08 (2013.01) [C01B 25/375 (2013.01); C25C 1/12 (2013.01); H01M 4/5825 (2013.01); H01M 10/0525 (2013.01); H01M 10/54 (2013.01); C01P 2006/80 (2013.01)] 20 Claims
 
1. A method for producing a lithium iron phosphate precursor by using a retired lithium iron phosphate battery as a raw material, wherein the retired lithium iron phosphate battery comprises a positive electrode, the positive electrode comprises lithium iron phosphate, an aluminum foil, and copper foil, and the method comprises the steps of:
(1) soaking a battery cell in acid, comprising: crushing a battery cell of a retired lithium iron phosphate battery, soaking the battery cell in acid, and performing filtering to obtain a filtered solution, wherein the filtered solution comprises copper ions;
(2) performing electrolysis to reclaim copper from the filtered solution, comprising: adding a copper cathode and a carbon anode into the filtered solution, and performing electrolysis on the filtered solution to obtain an electrolyzed solution;
(3) oxidizing ferrous iron, comprising: adding an oxidant into the electrolyzed solution, and performing oxidation reaction to obtain a post-oxidization solution;
(4) precipitating iron phosphate, comprising: performing a process of gradually adjusting pH of the post-oxidization solution to greater than 14 to obtain an iron phosphate precipitate and a post-reaction solution; and
(5) precipitating lithium carbonate, comprising: continuously adding a carbonate solution to the post-reaction solution to obtain a lithium carbonate precipitate, keeping adding the carbonate solution into the post-reaction solution until the lithium carbonate precipitate no longer increases, and performing filtering to obtain a precipitate mixture of the iron phosphate and the lithium carbonate, wherein the precipitate mixture is a lithium iron phosphate precursor.