Estimation of salt solubilities in hydrothermal systems

In this work we analyze the calculation of tlie solubility of salts at high tem- peratures and ~)ressiires. The prediction of so1ul)ility constants relies on the knowledge of the stantlard properties of the ions in water, while the calculation of ion concentration and speciation in solution at saturation requires a niethotl to estimate activity coeffi- cients and association constants. We discuss the achievements and 1iniita.tions of the ion-specific intermtion antl the 1iiea.n spherical iiiodels to estimate activity coefficients in pure and iiiixetl electrolyte systems. We emphasizes the importance of simple models depending on few molecular pa.ranieters and having a reasonable physical behaviour as it function of pressure and temperature.