Solvent Extraction Equilibria of FeCl_3 with TBP

摘要

Solvent extraction equilibria of FeCl_3 with TPB from chloride solutions were analyzed by considering chemical equilibria, extraction reaction, mass and charge balance equations. The activity coefficients of solutes in aqueous phase were calculated by Bromley equation while ideal behavior was assumed for species in organic phase. Extraction reaction of FeCl_3 with TBP in the experimental range of this study was determined from the dependence of the distribution coefficient of iron on the concentration of chloride ions. By applying ionic equilibria to the results of solvent extraction experiments, equilbrium constant of the extraction reaction was estimated to be 4.5 x 10~2. The equilibrium concentrations of solutes in both phases after extraction could be calculated with the ionic equilibria developed in this study. The predicted distribution coefficients of iron agreed well with those measured.