Roasting and Leaching of the Positive Electrode Active Materials from Spent Lithium-ion Batteries

Roasting process and leaching behavior of lithium cobalt oxide was studied via several steps,including wet crushing and separation,pre-roasting the mixture of lithium cobalt oxide and carbon powder,followed by further roasting in the presence of sodium sulfate and concentrated sulfuric acid.The results showed that more than 97wt% copper and 98wt% lithium cobalt oxide powders can be recovered after wet crushing and separation process.Moreover,97wt% of the cobalt can be recovered by pre-roasting at 700 ℃ for 2 h,then further roasting in the presence of sodium sulfate and concentrated sulfuric acid at 200 ℃ for 4 h,and final leaching of the roasted mixture at 70 ℃ for 30 min with hot water.Also,the result of X-ray Diffraction(XRD) test indicated that Na2Co(SO4)2and Na6Co(SO4)4were produced during roasting process.