Separation of cobalt/lithium in spent NCM-based lithium ion battery leaching solution via reactive extraction-reextraction with microdispersed (G1/L1+G2)/L2 emulsion

Separation of Co and Li in hydrometallurgy for the recovery of valuable metals from waste NCM-based lithium ion battery leaching solution is realized by extraction, with P507/TBP/sulfonated kerosene as extractant. Process intensification is realized via emulsion structure design and novel equipment development, aiming in overcoming operation limitations in traditional equipment caused by increased viscosity and phase ratio. Effects of emulsion structure and operating conditions on extraction are investigated. A multiphase emulsion, (G1/L1+G2)/L2, is designed and prepared by a micro-dispersion module. Efficient extraction is realized with (G1/O+G2)/W emulsion, with which Murphree efficiency of Co²⁺ reaches 99.1 % within a contacting volume of 7.35 mL, when reverse extraction is realized applying (G1/W+G2)/O emulsion. With (G1/L1+G2)/L2 emulsions, a single-stage extraction and reverse extraction process is realized in 9.11 s, with which Co²⁺/Li ⁺ solution with initial Co²⁺ concentration of 27.60 mol.% is separated into raffinate of 0.12 mol.% and strip liquor of 81.08 mol.%. The intensification fundamentals are studied, by calculating mass transfer coefficients in formation and flowing stages of varied heterogeneous systems and establishing mathematical models. This study presents simple and effective methods for intensifying extraction and reverse extraction processes with viscous extractants in spent lithium ion battery recycling.