Thermodynamics of phase equilibria in aqueous strong electrolyte systems

The middle range (MR) parameters of the LIQUAC model were improved as a function of temperature to allow the calculation of the activities of all the species in the solution over a wide temperature and concentration range. New parameters were recorrelated by using the experimental data of osmotic coefficients, vapor-liquid equilibria (VLE), mean ion activity coefficients and salt solubilities from the Dortmund Data Bank (DDB). The coordinates of the eutectics, the peritectics, and the ice-water equilibria of the aqueous electrolyte systems were represented with the model. Standard Gibbs energies of formation, standard enthalpies of formation, and heat capacities of various solids were retrieved from the fitting of their solubility products with respect to temperature or estimated using the group contribution method. The schematic phase diagrams for the salts in aqueous systems are presented in this work. A good agreement of calculated results with the published measurements is observed.