Recovery of valuable metals in spent lithium iron phosphate (LiFePO4) batteries by hydrometallurgical method

Due to their advantages, lithium iron phosphate (LFP) batteries are widely preferred in the electric vehicle market and their use is increasing day by day. With the rising the utilization of these batteries, it is expected that a significant amount of waste LFP batteries will be generated. Given the global lithium (Li) reserves will not be able to meet the demand and raw material requirements due to increased production, it is essential to efficiently recover valuable metals, especially Li, from waste LFP batteries. As a solution to this problem, this thesis aims to recover valuable metals such as Li, Fe (iron) and Al (aluminium) in waste LFPs by using inorganic acids, organic acids, and organic reductants. For this purpose, hydrometallurgical methods were conducted with two different reductants (hydrogen peroxide and glucose) and three different acids (sodium persulfate, acetic acid, and formic acid) resulting in the recovery of valuable metals. Al recovery performance ranged from 81-98%, Fe recovery performance ranged from 88-99% and Li recovery performance ranged from 87-97% when three different methods were applied to waste LFP batteries. The highest Li recovery performance (97%) was obtained by applying the method using formic acid and glucose. Accordingly, it was observed that high recovery efficiencies can be achieved by using organic acid and green reductant. Furthermore, it is predicted that strong inorganic acids can be shifted to using glucose instead of hydrogen peroxide as a reductant. It is also expected that by using glucose instead of hydrogen peroxide as a reductant, strong inorganic acids will not be needed, providing a more sustainable pathway, especially for Li recovery.