Author(s)

H. Itoh, H. Miyanaga, M. Kamiya & R. Sasai

Abstract

A novel cobalt recovering process from a cobalt-based cathode electrode in a lithium secondary cell was developed using a hydrothermal treatment combined with a pyrometallurgical technique. A cobalt-based cathode electrode was prepared by casting the mixture of LiCoO2, poly(vinylidene fluoride) and conductive carbon black onto an Al foil, and this model electrode was used as a test sample. A hydrothermal treatment of the cathode sample was carried out using pure water as a solvent in the temperature range of 423–473 K for the duration of 0–40 h. The hydrothermal treatment at 473 K for more than 15 h led the cathode sample to the disintegration into powdery particles. By the hydrothermal treatment under the optimum condition at 473 K for 20 h, more than 99.9 mass% of Co and 98 mass% of Al in the cathode sample was reclaimed as a form of spinel type Co(CoxAl2-x)O4 (0Keywords

spent lithium ion cell, hydrothermal treatment, cobalt recovery,pyrometallurgical treatment.