Recycled Lithium from Simulated Pyrometallurgical Slag by Chlorination Roasting

When the spent lithium ion battery is processed pyrometallurgically, lithium is generally fixed as slag with a high melting/boiling point which is difficult to be treated further. In this research, an innovative method to recycle lithium from pyro-slag by evaporation during chlorination roasting was proposed. Different chlorine donors, namely NaCl, AlCl3, and CaCl2 were evaluated by HSC software and experiments, among which CaCl2 possessed a stronger ability of chlorine donation in the chlorination roasting process. Experiments proved that 97.45% lithium was evaporated with the Cl/Li molar ratio of 1.8:1 when the mixture of a simulated slag and CaCl2 was roasted at 1000 °C for 90 min. XRD results demonstrated that the majority of LiAl(SiO3)2 in the slag was transformed into LiCl. All results implied that chlorination roasting should be a promising strategy for lithium recovery from the pyrometallurgical slag after pyro-treatment of the spent lithium ion battery.