Measurement of Mineral Solubilities in the Ternary Systems CaCl2–ZnCl2–H2O and KCl–ZnCl2–H2O at 373 K

Abstract

In this work, the solubilities of the salt minerals and the densities of solutions in two ternary systems, calcium chloride–zinc chloride–water and potassium chloride–zinc chloride–water, were measured at 373 K using an isothermal dissolution equilibrium method. Based on the determined equilibrium solubility data and the corresponding equilibrium solid phases, the phase diagrams and density diagrams of the two systems were plotted. The results show that the two ternary systems are complex. The invariant points, the univariant solubility curves and the solid crystalline phase regions are reported and discussed. The phase diagram of the ternary CaCl2–ZnCl2–H2O system at 373 K includes two invariant points, three univariant solubility curves and three solid crystalline phase regions corresponding to CaCl2·2H2O, CaCl2·ZnCl2·2H2O and ZnCl2. Also, the phase diagram of the ternary KCl–ZnCl2–H2O system at 373 K is constituted of two invariant points, three univariant solubility curves and three solid crystalline phase regions corresponding to KCl, 2KCl·ZnCl2 and ZnCl2. The influence of one of solute on the solubility of the ternary systems is also discussed in this work.