(54c) Chemical Modeling of Calcium Sulphate Phase Equilibria in Multicomponent Electrolyte Solutions

A new database was developed to successfully model the solid and aqueous phase equilibria in a number of hydrometallurgical processes using the Mixed Solvent Electrolyte (MSE) model of the OLI Systems software. In order to validate the predictability of the model developed, a number of experimental measurements were conducted in multicomponent solutions containing NiSO₄, H₂SO₄, MnSO₄, HCl, etc. from 25 to 90°C. The developed model accurately predicts the chemistry of calcium sulphate solid formation in the systems studied in this work as well as in multicomponent sulphate-chloride solutions in nickel hydrometallurgical processes. Since it is not practical to measure solubility data under all possible conditions, because of the large number of components involved, the developed model is a valuable tool for assessing calcium sulphate process chemistry for a wide variety of complex aqueous processing solutions.