抄録
Li-ion batteries (LIBs) are widely used as power source for mobile devices because they are comparatively lighter, smaller and higher energy density than other batteries. As the use of LIBs has rapidly increased, the recycling of spent LIBs becomes very important for the sustainable development.
A hydrometallurgical route including reductive leaching and selective precipitation steps was used to recover cobalt from spent LIBs. Furthermore, cobalt oxide powder was obtained by thermal treating the cobalt oxalate.
The cobalt rich powder (-16 mesh) obtained by several physical treatments, i.e., roll pressing, discharging, magnetic separation, and screening etc [1], were leached with aqueous 2 M sulfuric acid solution containing 6 vol% hydrogen peroxide. The leaching efficiency of cobalt was more than 99%. Then cobalt was selectively precipitated as cobalt oxalate (CoC2O4.2H2O) by adding 1.5 M oxalic acid (H2C2O4) to the solution. Overall 98% cobalt was recovered through this process from the cobalt rich powder. Finally, crystalline cobalt oxide (Co3O4) powder was obtained by thermal treating the cobalt oxalate in muffle furnace for 2 hr. The average particle diameter of cobalt oxide powder was 340 nm obtained by BET method.
