Measurements and calculations of solid-liquid equilibria in two quaternary systems: LiCl-NaCl-SrCl2-H2O and LiCl-KCl-SrCl2-H2O at 298 K

Using the method of isothermal dissolution equilibrium, stable phase equilibria of unreported strontium-containing systems LiCl-NaCl-SrCl2-H2O and LiCl-KCl-SrCl2-H2O at 298 K have been studied in accordance with the compositions of the underground brine in western Sichuan Basin. The experimental results show that there are no solid solution and complex salt in two quaternary systems. The phase diagram of quaternary system LiCl-NaCl-SrCl2-H2O consists of two invariant points, five isothermal dissolution curves and four crystallization regions. The quaternary system LiCl-KCl-SrCl2-H2O belongs to a simple type and the phase diagram consists of two invariant points, five isothermal dissolution curves and four crystallization regions. The solubilities of salts in the above systems were accurately calculated with Pitzer electrolyte solution theory. It was found that the calculated phase diagrams coincided basically with the experimental phase diagrams by evaluated the accuracy through the experimental results. Meanwhile, the applicability of Pitzer parameters selected in this paper was validated. (C) 2020 Published by Elsevier B.V.