This
paper describes the results of the solid–liquid equilibria
phase diagram in the two ternary systems sodium chloride–zinc
chloride–water and calcium chloride–zinc chloride–water
at 323 K using the method of isothermal dissolution equilibrium. Integrated
with the determined equilibrated liquid phase and humid residue composition,
the phase diagrams of the two systems were generated. At the same
time, the invariant points, the univariant solubility curves, and
the solid crystalline phase regions are displayed and discussed. The
results of the experiment testify that the types of two ternary systems
are classified as complex owing to the formation of a double salt.
The phase diagram of the ternary system NaCl–ZnCl2–H2O at 323 K is constituted of two eutectic points,
three univariant solubility curves, and three solid crystalline phase
regions corresponding to NaCl, ZnCl2, and 2NaCl·ZnCl2. The phase diagram of the ternary system CaCl2–ZnCl2–H2O at 323 K includes
two eutectic points, three univariant solubility curves, and three
solid crystalline phase regions corresponding to CaCl2·2H2O, CaCl2·ZnCl2·2H2O, and ZnCl2. The experimental densities of the equilibrium
solution were measured using a density bottle method. Based on the
Laliberte model, the theoretical density of each saturated solution
was calculated. The results show that the model gives worse prediction
for two ternary systems with stronger interactions between components.