Combined recovery of valuable metals from LiFePO4–LiCoO2 system without adding oxidant and reductant

Abstract

AbstractBased on the oxidation of ferrous ions in lithium iron phosphate and reduction of trivalent cobalt ions in lithium cobaltate, an innovative combined recovery process of lithium iron phosphate and lithium cobaltate powders is proposed. The effects of leaching conditions on leaching performance are studied and the optimal leaching conditions are obtained. Under these conditions, the leaching efficiencies of lithium and cobalt ions reach up to 99.92% and 81.11%, respectively. After removing ferric ions from leachate, the cobalt and lithium ions are separately recovered from the leaching solution. The final precipitation rate of cobalt ions is up to 97.71% with the purity of cobalt oxalate as 99.94%. In addition, the precipitation rate of lithium ions is 78.54% and the purity of lithium carbonate reaches up to 99.94%. Finally, the reaction path and mechanism for the combined recovery of lithium iron phosphate–lithium cobaltate system are preliminary investigated.