The recovery of metallic values from spent cathode active powders in lithium-ion battery was investigated in a deep eutectic solvent (DES) based on choline chloride (ChCl) and ethylene glycol (EG). The recovery yields of Li, Co, Mn and Ni metals were 97.2%, 99.2%, 97.6% and 100%, respectively, in the leaching process carried out at 180 °C, under 375 r/min magnetic stirring speed and at 10 g/L pulp density for 24 h using CC:EG 1:2 as solvent. Leaching yields very close to these results were also obtained after 12 h leaching using 200 W ultrasonic support (US) instead of magnetic stirring under the same conditions. 2 mol/L Na 2 CO 3 was used for co-precipitation of metals from metal loaded solutions. The precipitation efficiencies for Li, Co, Mn and Ni after co-precipitation at pH (11.6±0.05), 40 °C for 3 h are 85.7%, 95.8%, 99.8% and 89.9%, respectively. Furthermore, multiple utilization of DES was investigated, and three cycles were completed without loss of yield in both extraction and stripping stages. The precipitation product was calcined and characterized by XRD and SEM techniques.
Güloğlu et al. (Wed,) studied this question.