Isopiestic measurement and solubility evaluation of the ternary system (CaCl2 + SrCl2 + H2O) at T = 298.15 K

Water activity in the ternary system LiCl–SrCl2–H2O and its sub-binary systems has been elaborately measured by the isopiestic method. The measured water activities were used to justify the reliability of solubility isotherms reported in literature by correlating them with two thermodynamic models, that is, the extended Pitzer model and the Pitzer–Simonson–Clegg model. It was found that the extended Pitzer model cannot correlate consistently the water activities measured and either set of the solubility isotherms reported in literature for this concerned system, no matter how its parameters were adjusted. However, the Pitzer–Simonson–Clegg model can correlate consistently our measured water activities and the solubility isotherms reported by the literature (Kydynov et al. Issled. Obl. Khim. Tekhnol. Miner. Solei Okislov1965, 146–150), which should be more reliable than solubility data reported in other references.