Dual-stream valorization of spent LFP black mass via microwave-assisted NaHCO3 treatment: lithium phosphate-rich leachate and reusable iron-rich residue

The recycling of valuable elements and compounds from lithium iron phosphate (LFP) batteries remains challenging due to the low economic value of Fe-P components and the limitations of conventional pyrometallurgical, hydrometallurgical, and alkaline-based processes, which are often energy-intensive or reagent-demanding. In this work, a novel and sustainable treatment for LFP black mass is proposed, based on the synergistic combination of microwave irradiation in the presence of sodium bicarbonate. This approach promotes the controlled decomposition of the LFP structure under relatively mild conditions, inducing the simultaneous formation of water-leachable lithium and phosphorus species and the transformation of iron into stable oxide phases. NaHCO3 decomposition (CO2 release) further contributes to structural modification and enhanced reactivity.