Thermodynamic Simulation on Rb2SO4-Cs2SO4-MgSO4-H2O System at 25 ºC

Abstract

The Pitzer ion-interaction was applied to calculate the solubility isotherms of quaternary system Rb₂SO₄-Cs₂SO₄-MgSO₄-H₂O at 25 ºC in which the mixing crystals were formed. Theoretical phase equilibrium of Rb₂SO₄-Cs₂SO₄-MgSO₄-H₂O has been obtained assuming that no new solid phases crystallize in them. The calculated phase diagram consists of five crystallization fields, three invariant points and seven univariant curves. The five crystallization fields correspond to Rb₂SO₄, Cs₂SO₄, MgSO₄·7H₂O, Cs₂SO₄·MgSO₄·6H₂O and Rb₂SO₄·MgSO₄·6H₂O. The results of calculation can be used to model salt crystallization during the concentration of brines.