Optimization of the recycling process of spent LFP-batteries using the DEHPA/menthol deep eutectic solvent

The previously developed resource efficient technological scheme of the hydrometallurgical process of metal separation from leaching solutions of lithium-iron-phosphate batteries is optimized. The approach used in this work is based on integrating the method of liquid pseudomembranes and hydrophobic deep eutectic solvents into the process scheme, combining environmental safety (biodegradability, low toxicity) with high efficiency. A step-by-step approach to optimizing the technological scheme is presented in order to reduce the number of devices, the degree of concentration, the efficiency of extraction, and the purity of the final products. The liquid pseudomembrane method is shown to allow reducing the number of device units from 10 to 8 as compared to the countercurrent scheme. A significant concentration of iron(III) ions by 25 times and copper(II) and aluminum(III) by 5 times in the re-extract phase is achieved when the purity of the products reached 100% (Cu), 99.8% (Fe), 99.8% (Al), and 99.5% (Li). As a result of, an optimized closed-loop scheme is proposed. The proposed methodology demonstrates that the combination of the LPM method and "green" solvents opens the way to resource efficient and environmentally balanced hydrometallurgy.

hydrometallurgy, liquid pseudomembranes, deep eutectic solvents, LFP batteries, resource conservation, metal extraction