Lithium recovery from slags

Abstract

A Li recovery process comprises the steps of powdering the metallurgical slag to a particle size distribution having a D50 of less than 100 μm; contacting, in an aqueous medium, the Li-containing metallurgical slag, and an alkaline Ca-compound, provided in amounts selected to obtain a molar ratio of the Ca in the Ca-compound to Li in the slag of at least 0.75, thereby obtaining a suspension; heating the suspension to a temperature of more than 80° C. for at least 30 min, thereby obtaining a leached suspension; and, separating solids from liquids in the leached suspension, thereby obtaining a leach solution containing a major part of the Li, and a solid residue containing Ca. This alkaline leaching process allows for a straightforward recovery of battery-grade LiOH from the leach solution, while consuming fewer reagents than known acidic leaching processes.

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