US Patent 11821056 Lithium extraction method

The lithium extraction method includes providing lithium phosphate containing impurities of an alkaline earth metal; dissolving the lithium phosphate and the impurities in an acid; and preparing a lithium-containing solution by adding an additive to a solution prepared by dissolving the lithium phosphate and the impurities in the acid. The additive is a substance capable of simultaneously precipitating phosphate anions and the impurities, and the lithium-containing solution prepared through addition of the additive is basic.