Aluminum removal from LiFePO4/C leachates and sequential recovery of battery-grade FePO4 and Li2CO3.

The removal of Al impurities and the regeneration of valuable Fe/P/Li resources from spent lithium iron phosphate (LFP) battery are critical steps in advancing the circular economy within the battery industry. In this work, we propose a simple, clean, and cost-effective method based on selective phosphate precipitation for the removal of Al(III) from the acid leachate of spent LFP, followed by the sequential recovery of battery-grade FePO4 and Li2CO3. The results demonstrate that 95.7 % of Al(III) precipitated as AlPO4·xH2O and Fe1.77Al0.23PO4SO4OH·6H2O, and the residual Al(III) concentration in the purified liquid kept around 80 mg/L under the optimal condition. The selective precipitation of Al(III) from spent LFP leachates followed the Johnson-Mehl-Avrami kinetic model and was chemically controlled with an activation energy of 60.12 kJ/mol. The recovered FePO4 and Li2CO3 products both met the battery-grade standards, and the regenerated LFP/C exhibited excellent electrochemical performance. Pilot-scale experiments and economic evaluations further confirmed the feasibility of this scalable process. This work provides guidance for the recovery of precursor materials from spent LFP and is expected to promote sustainable recycling strategies within the LFP battery industry.