Enhancing Li+ exchange efficiency of lithium slag via alkaline adjustment: Investigation into the multi-cation systems and insights for waste recycling

The growing demand for lithium batteries promotes the generation of a large amount of spodumene leached residue (SLR) in the lithium extraction industry, which leads to potential environmental challenges. To seek a proper treatment strategy for SLR, its ion-exchange behaviors were investigated systematically in solutions containing Li + , Na + , K + , Ca 2+ , and Mg 2+ . The results indicated that the SLR exhibited a pronounced positive selective response toward Li + , resulting in a Li 2 O content of 0.74%-1.86% after ion-exchange in the mixed-cation system. Moreover, a proper adjustment of solution alkalinity can further enhance H + /Li + ion-exchange, significantly improving the exchange efficiency to a maximum Li 2 O content of 8.44%. Repeated experiments as well as industrial SLR indicated good re-utilization potential. The present work provides a novel pathway for the resource utilization of SLR and offers a feasible new approach for lithium recovery from complex ion systems.