Thermodynamics of Solvent Extraction of Rhenium with Trioctyl Amine

Abstract

The equilibrium molalities of ReO4− in the system {TOA + (NH4)ReO4 + n-C7H16 + HCl + H2O} were measured at ionic strengths from (0.1 to 2.0) mol·kg−1 in an aqueous phase containing NH4Cl as the supporting electrolyte and at a constant initial molality of extractant in the organic phase, at temperatures from (278.15 to 303.15) K. The standard extraction constants K0 at various temperatures were obtained by the methods of Debye−Huckel extrapolation and Pitzer polynomial approximation. Thermodynamic properties for the extraction process were calculated.