Recovery of valuable metal ions from the spent lithium-ion battery using aqueous mixture of mild organic acids as alternative to mineral acids

A well characterized cathode material (LiCoO2) recovered from spent lithium-ion battery is dissolved in aqueous mixture of citric acid (chelating agent) and ascorbic acid (reductant) at 80 degrees C. The dissolution proceeds with a reductive-complexing mechanism, and complete dissolution occurs in about 6 h when stoichiometric amount of C/A is used. The dissolution rate constants (k) are 3.1 x 10(-3) min(-1) for Li and 0.8 x 10(-3) min(-1) for Co ions as determined by 'cubic rate law' plots. The formation of Co(III)- to Co(II)-citrate during the dissolution is confirmed from the UV-Vis spectra. The dissolved solution was subjected for selective precipitation of cobalt as Co-oxalate and lithium as LiF using oxalic acid and NH4F, respectively. The present study has a merit when compared to literature reports as we make use of mild organic acids as alternatives to mineral acids. (C) 2014 Elsevier B.V. All rights reserved.