A clean and efficient process for simultaneous extraction of Li, Co, Ni and Mn from spent Lithium-ion batteries by low-temperature NH4Cl roasting and water leaching

The recycling of valuable metals from spent lithium-ion batteries (LIBs) has great significance for environmental protection and resource conservation. In this paper, a low-temperature clean chlorination roasting-water leaching process was proposed to simultaneously extract Li, Ni, Co and Mn from cathode material (NCM) of spent LIBs. The temperature range of chlorination roasting was determined by thermodynamic analysis to be 250-600 °C. The effect of some factors on the conversion of valuable metals in the process of chlorination roasting and water leaching was systematically studied. The results showed that more than 98 % of Li, Co, Ni and Mn could be extracted under optimized chlorination roasting and water leaching conditions. The chlorination roasting mechanism and phase transformation evolution was determined by means of thermodynamic analysis, TG-DTA, XRD, SEM and EDS. The extraction of valuable metals was realized by the reaction of the metal oxides produced by the decomposition of NCM with NH4Cl or its evolved HCl to form water-soluble metal chlorides or chlorinated metal-ammonium complexes. The chlorination technique using NH4Cl provided an effective and clean approach for the simultaneous extraction of Li, Co, Ni and Mn from spent LIBs.