Hydrometallurgical recycling of waste lithium iron phosphate batteries using different organic acids and reductants

Abstract This study aimed to examine lithium (Li) leaching efficiency and Li recovery yield from waste lithium iron phosphate batteries using various organic acid medias and reductants. To achieve this goal, a hydrometallurgical recycling process was employed, involving the use of reductants-hydrogen peroxide (H 2 O 2 ) and glucose—in conjunction with organic acids of acetic acid and formic acid. The leaching experiments were conducted under varying conditions of acid concentration, reaction time, and reductant type to determine their influence on Li leaching performance. According to experiment results, Li leaching efficiencies obtained ranged from 54–97%. The highest achieved leaching efficiency was obtained by using formic acid as the leaching reagent in combination with glucose as the organic reductant. This study contributes to literature as the first to investigate the combination of formic acid and glucose for the recovery of valuable metals from waste LFPs, offering a green and sustainable alternative to traditional reducing agents. These findings demonstrate that the use of organic acid and a glucose reducing agent leads to high leaching yields can be achieved. Following leaching, a precipitation process was applied to the leachate, through which Li was recovered in the form of salts as lithium carbonate or lithium phosphate. Li recovery efficiency was found to be approximately 90% across all experiments, regardless of the leaching conditions. The use of glucose instead of H 2 O 2 in the leaching process is expected to eliminate, the need for strong inorganic acids, offering a more sustainable route for Li recovery following the precipitation step.