Development of process flow sheet for recovery of high pure cobalt from sulfate leach liquor of LIB industry waste: A mathematical model correlation to predict optimum operational conditions

The paper contains a new hydrometallurgical process flow sheet for the recovery of high pure cobalt sulfate solution/salt from waste LiCoO2 cathodic active material generated from lithium ion battery (LIB) industry waste. Cobalt was recovered as cobalt sulfate from sulfate leach liquor by solvent extraction process using Cyanex 272 as an extractant. For quantitative extraction of pure cobalt from waste LiCoO2 different process parameters such as concentration of Cyanex 272, O/A volume ratio, McCabe–Thiele extraction isotherm, scrubbing isotherm required were optimized. A mathematical model was developed to correlate metal extractability and Cyanex 272 concentrations and volume content. Optimum conditions required for quantitative extraction of pure cobalt sulfate/salt using Cyanex 272 were estimated by a proposed model. From predicted model, the mechanism for extraction and McCabe–Thiele isotherm for extraction were derived and compared with obtained results. A good agreement between proposed model and observed results was indicated. The cobalt loaded Cyanex 272 was stripped with sulfuric acid and 99.99% pure cobalt sulfate was obtained.