Leaching of valuable metals from spent batteries of electric vehicles using disodium ethylenediaminetetraacetic acid.

This study investigates the efficient extraction of metals, particularly cobalt, from NMC black mass using NaEDTA as a leaching agent without the need for a reducing agent. Response Surface Methodology (RSM) optimized NaEDTA concentration, liquid-solid ratio, and initial pH, identifying optimal conditions as 0.5 M NaEDTA, a liquid-solid ratio of 30 mL g, and an initial pH of 4.00. Under these conditions at 80 °C and 300 rpm for 30 min, the highest cobalt leaching efficiency of 71 % was achieved Moreover, nickel (69 %), manganese (70 %), lithium (78 %), copper (63 %), aluminum (42 %), and iron (64 %) were also co-leached. Initial pH was found to significantly influence elemental leaching, with X-ray diffraction (XRD) confirming metal precipitation under high alkalinity. Leaching kinetics demonstrated rapid dissolution of cobalt, nickel, manganese, and lithium within 45 min, reaching the highest efficiencies of approximately 96 %. The highest leaching yields of both aluminum (93 %) and copper (99 %) was attained at 60 min and 90 min, respectively, while iron (70 %) was partially leached throughout the experiment, due to its role as a reducing agent. Residual traces were minimal (<1 % wt) after 45 min. This study provides the first comprehensive assessment of copper, aluminum, and iron leaching efficiencies using EDTA as chelator under weakly acidic conditions and first introduces NaEDTA as an effective, cost-efficient, and environmentally friendly agent for metal extraction from NMC black mass. These findings advance hydrometallurgical strategies for hazardous battery recycling, offering valuable insights for sustainable resource recovery and environmental stewardship.