Proposal of novel physical concentration flow for the recovery of cathode materials from spent mobile phone LIBs

Considerable amount of minor rare metals, such as Co, Ni, Mn, Li are contained in spe nt lithi um ion bat teries (LIBs) and these me tals should be recov ered. Recently hydrometallurgical processes were developed to treat the defective cathode materials gener at ed from their ma nuf acturi ng pla nts, but the effective pr ocess of conc entrati ng cathode materials from spent LIBs has not been developed yet. This paper proposed a proper flowchart for concentrating the cathode materials, especially Co, from the spent LIBs by combining roasting, selective crushing, screening, flotation and magnetic separation. Two kinds of roasting processes, single stage and two-stage, have been proposed. In the two-stage roasting; the conditions of the first stage were set at relatively lower temperature and in shorter time in order to depress the oxidation of Al and Cu sheets and keep the sheet structure in non-destructive form in order to remove them into coarse fraction by screening after adequate crushing; and the conditions of the second stage were at relatively higher temperature and in longer time in order to improve the transformation of LiCoO₂ into CoO and/or metal Co and to facilitate the subsequence magnetic separation. It was found that the selective crushing and screening after the two-stage roasting could concentrate cathode materials into fine fractions and Al and Cu components could be removed into coarse fractions and that flotation could remove C component effectively as a froth and magnetic separation could remove Al components. Finally, we could produce the concentrate of 59.4 wt% Co with the recovery of 85.0 % by the above flowchart.