Modeling of solvent extraction of zinc from sulphate solutions with D2EHPA

Abstract

A thermodynamic model based on chemical equilibria with mass and charge balance equations has been developed for the solvent extraction system consisting of ZnSO4-H2SO4-H2O-D2EHPA-kerosene. The activity coefficients of all solutes in the aqueous phase were calculated by Pitzer's equation. By applying this model, the equilibrium concentrations of solutes were calculated from the concentration of zinc and pH. The extracted metal species was ZnHA3 and extraction equilibrium constant was found to have a value of 9.77 × 10-2 from the slope of the equilibrium extraction data. The predicted distribution coefficients of zinc were in good agreement with experimental results.