Lithium ion batteries (LIB) have been widely applied as power sources for electric devices owing to their light weight and high energy densities. A large amount of cobalt (Co) was used as cathode materials in the LIB, so establishment of Co recycling from spent LIB is demanded. Optimization of heating and grinding process on classification for Co recycling before physical separation from spent LIB was investigated in this study. Lithium cobalt oxide (LiCoO2) in spent LIB was transformed to CoO, which was more easily decomposed than LiCoO2 by heating process. Coexisting materials of carbon as an anode in the LIB promoted LiCoO2 decomposition at a lower temperature than the theoretical value for LiCoO2. Furthermore, slow heating rate was effective for grain growth of Co oxide and Co metal. In the grinding process, iron ball as high density media was more effective grinding media than wooden ball as low density media. It was suggested that heating process at low temperature with slow heating rate and grinding process by using high density media could promote the separation of Co and Al by screening process.
