With development in high-tech industry and electronic products have made recycling electronic waste one of the most important issues worldwides. Many researches focus on the recovery of waste battery using the phosphorus extractant for selective separation of valuable metals. This study aims to develop the amine-based extractant for recycling Co in lithium-ion batteries. In this study, the cathode materials after NaOH soaking and calcination were dissolved within 2 M sulfuric acid under 20 g/L solid loading, 2 vol% of H2O2 as reducing agent at 60 °C for 60 min. The acid dissolution rate of cobalt assisted with ultrasound attained 70.67%. Then, the extraction of metals from the acid liquid were conducted using TOA and Aliquat 336 amine-based extractants. The extracting parameters include pH, extraction time and molar ratio of extractant. The extracting efficiency of cobalt using TOA as extractant from 8M HCl and 2M H2SO4 reaches 97.24% at pH 4, molar ratio = 1 in 20 min. Results of electrolysis showed that the current efficiency of recovering Co metal on the cathode attained around 30% under a constant current 15 mA/cm2 within 2 hours. Further, removal efficiencies of Co, Mn and Ni reached 100% in 6 h. Since the reduction rate of Co is greater than that of Ni, the electrodeposition time was suggested to be 150 min, at which the recovery of Co and Ni were 85% and 60%, respectively, to increase the purity of Co metal. Almost 100% of Mn was removed as manganese dioxide over the anode surface. Under the low current density of 5 mA/cm2 the purity of cathodic Co metal was 99.7%; as increasing the current density to 15 mA/cm2, Co metal coule be still properly recovered with a purity as high as 98% .

Amine extractant, Electrochemistry, Waste lithium batteries, Cobalt