Process study of chloride roasting and water leaching for the extraction of valuable metals from spent lithium-ion batteries

A chlorination roasting-water leaching process to recover Li, Ni, Co, and Mn from spent Li-ion batteries is introduced in this paper. The key parameters were studied and optimized, over 98% of Li, Ni, and Co, and 97% of Mn can be leached out under the most suitable condition of 350 °C roasting temperature, 30 min roasting time, and a 2:1 mass ratio of NH4Cl to cathode powder. During the roasting process, NH4Cl is first sublimated and transformed into H3N···HCl(g) complex, and then reacts with LiNi0.5Co0.2Mn0.3O2 to produce the intermediate products (NH4)2MCl4·2H2O (M = Ni, Co, Mn), which further decomposed to water soluble NH4MCl3 (M = Ni, Co, Mn) at higher roasting temperatures. The results show that the chlorination roasting-water leaching process can be efficient in extracting valuable metals from spent lithium-ion batteries, providing a new recycling route for spent lithium-ion batteries.