Selective recovery of lithium from spent lithium-ion battery by an emission-free sulfation roasting strategy

Abstract

As the economy recovered from the COVID-19 epidemic, the price of Li2CO3 skyrocketed to the highest. Recovery of lithium from spent lithium-ion batteries (LIBs) is significant for addressing lithium shortage and environmental issues. Sulfation roasting is often accused of being unsustainable and not environmentally friendly due to the consumption of expensive sulfation reagents and emission of SO2. Herein, a novel and green recycling process for selective separation of lithium from spent LiMn2O4 (LMO) batteries was proposed based on a SO2 emission free sulfation roasting with waste copperas. Lithium in the cathode power were selectively sulfated into soluble Li2SO4 with a conversion of 99.50%, while manganese was riched as insoluble oxides. At low temperature (e.g. 400 °C), LMO were difficult to be sulfated due to the limited sulfation ability of SO42- and mass transfer. When the roasting temperature reached 700 °C, SO2 was produced and the generated SO2 reacted in situ with the LMO to form Li2SO4 and MnSO4, preventing SO2 emissions into the atmosphere. As temperature continued to increase, the MnSO4 acted as a sulfation reagent and sulfated the unreacted LMO. All the sulfur was immigrated in Li2SO4, rather than being emitted as SO2.