Solvent Extraction of Perrhenate from Sulfuric Acid Medium by Triisooctylamine

Abstract

In sulfuric acid medium, triisooctylamine was used as extractant to separate perrhenate from the aqueous phase. Molalites of perrhenate in the aqueous phase were measured from 278.15 K to 303.15 K at impurity ionic strength from 0.2 to 2.0 mol·kg–1. Standard extraction equilibrium constants K0 at different temperatures were calculated by polynomial approximation method. Some microcosmic property values in the process were investigated and obtained by Pitzer’s theory, which indicated enthalpy and entropy were both dominant thermodynamic factors.