Abstract
An experimental study of the recovery and purification of lithium from spent lithium batteries was carried out, taking advantage of the characteristics of lithium ion and its carbonate. More than 75 % of the lithium contained in the whole battery or its anode component can be leached with sulfuric acid where the pH of the final pregnant liquor is 7.7 or higher, the other metals being left in the residue as their hydroxides.
The liquor is concentrated by evaporation to 15 g/l in lithium content, followed by the addition of saturated sodium carbonate solution to precipitate lithium carbonate. Sodium contained in the lithium precipitate is removed by washing with a small amount of hot water. The processes must be carried out at around 96-98°C, and the recovery of lithium from the pregnant liquor is 80 %, the purity (the ratio of lithium to sodium) being 99 %. The barren liquor contains the remaining lithium and seven times as much sodium. Lithium is recovered by solvent extraction with a kerosene solution of LIX 51 (α-perfluoro-alkanoyl-m-dodecylacetophenone) and TOPO (tri-n-octylphosphine oxide). Lithium of 99% purity was obtained by single extraction followed by single scrubbing with hydrochloric acid.
