(Solid + Liquid) Phase Equilibria in the Quaternary System (NaBr + MgBr2 + CaBr2 + H2O) at 298.15 K

Abstract

The solubilities of salts in the (NaBr + MgBr2 + CaBr2 + H2O) system and its two ternary subsystems (NaBr + MgBr2 + H2O) and (NaBr + CaBr2 + H2O) are investigated at 298.15 K by the isothermal dissolution equilibrium method. The equilibrium phase diagrams of the three systems were obtained using the experimental results. In the three systems, neither solid solution nor double salt was found. In the two ternary phase diagrams, there are two invariant points, three dissolution equilibrium curves and three crystallization fields. The equilibrium solid phases in the (NaBr + MgBr2 + H2O) system are NaBr, NaBr·2H2O and MgBr2·6H2O, and those in the (NaBr + CaBr2 + H2O) system are NaBr, NaBr·2H2O and CaBr2·6H2O. The phase diagram of the quaternary system at 298.15 K consists of one invariant point, four solubility curves and four regions (corresponding to NaBr, NaBr·2H2O, MgBr2·6H2O, and CaBr2·6H2O). The solubilities of salts in the quaternary system and its two subsystems were calculated at 298.15 K by Pizter eq...