Solid-Liquid Metastable Equilibria in the Quaternary System (NaCl plus LiCl + CaCl2 + H2O) at 288.15 K

The solubility and the physicochemical properties (densities, viscosities, refractive indices, conductivities, and pH) of the liquid-solid metastable system (NaCl + LiCl + CaCl2 + H2O) at 288.15 K have been studied using the isothermal evaporation method. On the basis of the experimental data, the dry-salt phase diagram, water phase diagram, and the diagram of physicochemical properties versus composition in the system were plotted. The dry-salt phase diagram of the system includes two three-salt cosaturated points of (CaCl2 center dot 6H(2)O + NaCl + CaCl2 center dot LiCl center dot 5H(2)O) and (LiCl center dot H2O + NaCl + CaCl2 center dot LiCl center dot 5H(2)O), five metastable solubility isotherm curves, and four crystallization regions corresponding to sodium chloride (NaCl), lithium chloride monohydrate (LiCl center dot H2O), calcium chloride hexahydrate (CaCl2 center dot 6H(2)O), and the double salt LiCl center dot CaCl2 center dot 5H(2)O. No solid solution was found. It was found that the physicochemical properties in the metastable equilibrium solution change regularly with increasing CaCl2 concentration.