Recovery of cobalt from spent lithium ion batteries by using acidic and basic extractants in solvent extraction process

Abstract

Solvent extraction studies of cobalt from aqueous chloride solution have been focused on using three acidic (Cyanex301, D2EHPA, Cyanex272) and two basic (Alamine336, TOA) extractants. The effects of operating variables, such as time, chloride or sulfate ions, aqueous phase acidity, concentration of the extractant, temperature and various acid solutions in the metal stripping from the loaded organic phase were studied. The values of the stoichiometric coefficients for reactive extraction of cobalt from aqueous chloride solution were calculated by using the relationship between log D and equilibrium concentration of the five extractants. According to the results, Cyanex301 extraction system led to an increase in extraction efficiency of cobalt from aqueous solution in the low concentration range (0.1 M) from the diluted chloride solution (pH = 6–7), while, TOA extractant was an appropriate extractant for cobalt extraction in chloride acidic aqueous solution (6 M HCl). The results illustrate that the increase in temperature was favorable for the extraction cobalt with the five extractants. In addition, the useful data for recovery of cobalt from the synthetic leach liquor of the spent lithium ion batteries were obtained from the experimental data.