Method for recovering lithium from waste

Abstract

A method for recovering lithium from waste, according to the present invention, comprises the steps of: preparing lithium carbonate; converting the lithium carbonate into a slurry containing lithium hydroxide and calcium carbonate by using calcium hydroxide; solid-liquid separating the slurry; firstly purifying the solid-liquid separated aqueous lithium hydroxide solution to obtain solid waste and a purified aqueous lithium hydroxide solution; secondly purifying the purified aqueous lithium hydroxide solution through an ion exchange resin; and crystallizing the aqueous lithium hydroxide solution having passed through the second purifying step to obtain lithium hydroxide, wherein: in the second purifying step, in order to regenerate the ion exchange resin, an acid regeneration method is used, and thus acid regeneration wastewater is generated therefrom; in the step of crystallizing the aqueous lithium hydroxide solution, a lithium hydroxide purge solution is generated; through a step of carbonating the lithium hydroxide purge solution, lithium carbonate and lithium carbonate purge wastewater are obtained; and part of the lithium hydroxide purge solution is directly input to the carbonating step, and the remaining part of the lithium hydroxide purge solution is mixed with mixed wastewater of the acid regeneration wastewater and the lithium carbonate purge wastewater to be input to the carbonating step.

Images