Experiment and Calculation of Solid Liquid Phase Equilibria in the Ternary System KCl−KBr−H2O at T = 273 K

In this work, the solid-liquid phase equilibrium in the ternary system KCl−KBr−H 2 O at T = 273 K has been investigated by using the isothermal dissolution equilibrium method. Based on determined solubility data of saturated liquid phase and corresponding humid residue composition, the experimental phase diagram has been constructed. The result shows that the type of the system is classified as completely solid solution type due to the existence of solid solution K(Cl, Br). The phase diagram of the ternary system KCl−KBr−H 2 O at 273 K is divided into an unsaturated liquid phase filed and one solid crystalline phase region corresponding to K(Cl, Br) by an univariant solubility curve on which there is without any invariant point. The function which described the relationship between the composition of solid solution and the solubility of two salts in saturated liquid phase was constructed by multiple regression. The Pitzer equation has been selected to calculate the solubility data in the ternary system KCl−KBr−H 2 O at T = 273 K. The solubility modelling approach agrees with experimental solubility data.