Total Lithium Extraction from Lithium Iron Phosphate Batteries Using Tartaric and Formic Acids: Comparative and Kinetic Study

Artikel i vetenskaplig tidskrift, 2025

The rapid expansion of the battery market also increases the demand for raw materials, particularly metals. Recently, new technologies have been implemented to recover valuable materials from secondary resources. In this investigation, a hydrometallurgical method for lithium iron phosphate (LiFePO4, LFP) battery recycling is proposed. The effectiveness of tartaric (C4H6O6) and formic (CH2O2) acids for lithium extraction was evaluated and compared. The effect of organic acid concentration, temperature, oxidant addition, and solid–liquid ratio were the parameters analyzed. This study demonstrated that both agents extract 100% of lithium. Kinetics analysis showed that lithium leaching was controlled by chemical reaction, estimated the apparent activation energies ((Formula presented.)) of 42.4 kJ/mol and 38 kJ/mol for CH2O2 and C4H6O6 systems, respectively. Moreover, the effect of oxidants in preventing the co-dissolution of specific impurities like iron and phosphorus, especially in formic acid solutions, has been demonstrated. The experimental conditions, 100 g/L, 0.5 M CH2O2, 2.5 vol% H2O2, 25°C, and 250 rpm, suppressed the iron and phosphorus leaching by >90%. This work presented an alternative method that operates at room temperature and employs nontoxic substances to improve recycling techniques for LFP batteries via complete lithium extraction.