Novel targeted extraction of lithium: An environment-friendly controlled sulfidation roasting technology and mechanism for recovering spent lithium-ion batteries

Due to the needs of protecting the environment and recycling resources, the extraction of lithium from spent lithium-ion batteries has become increasingly important. Different from the traditional roasting process, a novel approach for the selective recovery of lithium from spent LiCoO2 (SLCO) through low-temperature sulfidation roasting was proposed in the present work. The thermodynamics of the sulfidation roasting was investigated and phase transformation was detected. The results showed that the S2 gas generated from the decomposition of pyrite converted LiCoO2 into Li2SO4 and cobalt sulfides. Under optimal experimental conditions, lithium can be selectively leached with a yield of more than 99% through water immersion treatment, resulting in around 20% improvement in the overall recovery rate of the metal compared to current industrial practices. The thermochemical process did not produce toxic SOx gases, whereas the selective leaching process for lithium did not require additional reagents, resulting in good environmental and economic benefits.