Solvent extraction for zinc and manganese ion recovery

The feasibility of recovering zinc and manganese ions from spent batteries using the solvent extraction method was investigated. The tests suggested that Di (2 ethylhexyl) phosphoric acid (P204) is a suitable extractant according to the experimental results for equilibrium of zinc and manganese in organophosphate extractants. The effect of operating conditions on the extraction behavior was studied. The results showed higher solution pH, inert diluents and lower metal ion concentrations resulted in larger distribution coefficients. Zinc was extracted first into the organic phase for a zinc and manganese solution since the selectivity of zinc is larger than that of manganese. Simulated cross flow extraction results showed that almost all the metal ions can be recovered with suitable operating conditions and that the amount of residual metal in the water was lower than that required by the Integrated Wastewater Discharge Standard GB 8978 1988. The solvent is easily regenerated, and can be reused so a feasible solvent extraction process can be developed to recover zinc and manganese from spent batteries.