Vapor–Liquid Equilibria for the ZnSO4–H2SO4–H2O and MgSO4–H2SO4–H2O Systems at (30, 60, 90, and 101.3) kPa

Abstract

Vapor-liquid equilibria (boiling points) data for the ZnSO4H2SO4H2O and the MgSO4H2SO4H2O systems were determined by the quasi-static ebulliometric method at (30, 60, 90, and 101.3) kPa. The boiling points of the ZnSO4H2O and the ZnSO4H2SO4H2O systems were used to regress new chemical model parameters with the average absolute deviation of only 0.08 K. The model was verified by comparing its predictions of the solubility of zinc sulfate in water from (273.15 to 310.15) K and the activity of water in zinc sulfate solution at 298.15 K with literature data. Furthermore, the distributions of the ZnSO4(aq) (ZnSO4 neutral species), Zn2+, MgSO44(aq) (MgSO4 neutral species) and Mg2+ species were predicted. The ZnSOO4-H2SO4-H2O system speciation provided a thermodynamic basis for the empirically optimized zinc sulfate concentrations currently employed in the Zn electrowinning industry.