Method for extracting lithium from waste lithium battery

Abstract

The present disclosure discloses a method for extracting lithium from waste lithium batteries, which comprises: leaching positive electrode powder of the waste lithium battery in hydrochloric acid, and obtaining leaching solution by filtering; removing copper and iron from the leaching solution, and then introducing hydrogen sulfide gas for reaction, and performing solid-liquid separation to obtain first filter residue and first filtrate; adding potassium permanganate to the first filtrate, and performing solid-liquid separation to obtain second filter residue and second filtrate; performing spray pyrolysis on the second filtrate to obtain solid particles and tail gas, washing the solid particles with water to obtain a lotion, washing and collecting the tail gas and then mixing the tail gas with the lotion to obtain lithium salt solution. In the present disclosure, the positive electrode powder is leached with hydrochloric acid to obtain the hydrochloric acid leaching solution, and hydrogen sulfide is used to precipitate nickel and cobalt after removing the copper and iron impurities in the leaching solution in turn, and potassium permanganate is added to precipitate manganese ions to generate manganese dioxide. Spray pyrolysis converts the aluminum and magnesium in the solution into oxides and lithium salt is separated. The entire reaction process does not require organic solvent extraction and reduces the loss of lithium.