Process intensification in the extraction of Mn from spent Li-ion battery simulated leachate via (G1/W+G2)/O microdispersion system with phase inversion

Recycling valuable metals from spent Li-ion batteries effectively alleviates the shortage of metal resources as well as avoids harm to human health and ecological environment. In this study, D2EHPA/TBP/sulfonated kerosene was selected as the extractant to conduct the process intensification in the reactive extraction of Mn. Five different methods with stepwise intensified mass transfer were designed to prepare liquid/liquid, gas/liquid/liquid and gas/liquid/gas/liquid systems, respectively. Effects of the dispersion method, fluid flow rates and residence time on the mass transfer performance were systematically investigated. The optimal structure and its efficient operating interval for process intensification were recommended, in which the Murphree efficiency of Mn reached 95.3% at the outlet of the dispersion module and reached 99.2% within a contacting volume of 2.12 mL, while was only 35–45% within 21.36 mL in the millimeter-dispersed emulsion system. The intensification fundamentals were discussed, via calculating the mass transfer coefficients and establishing corresponding mathematical models. This study provided simple and effective methods for process intensification of reactive extraction with viscous extractants in recycling valuable metals from spent Li-ion batteries.