Measurements and Predictions of Phase Equilibria in Quinary System NaBr–KBr–MgBr₂–SrBr₂–H₂O at 273.15 K

In order to efficiently exploit and utilize bromine-rich underground brine resources of China, the quinary system NaBr–KBr–MgBr2–SrBr2–H2O at 273.15 K was studied in detail by the isothermal dissolution equilibrium method. According to phase equilibrium data in the quinary system, the three-dimensional space phase diagram of the quinary system was constructed, and there were two invariant points, seven univariate curves, and five solid-phase crystallization regions NaBr·2H2O, KBr, SrBr2·6H2O, MgBr2·6H2O, and KBr·MgBr2·6H2O. And three simplified dry salt phase diagrams were drawn for the quinary system under saturation conditions of NaBr·2H2O, KBr and SrBr2·6H2O. Furthermore, the solubilities of salts in the quinary systems NaBr–KBr–MgBr2–SrBr2–H2O at 273.15 K (saturated with NaBr·2H2O, KBr, and SrBr2·6H2O) were theoretically predicted by using the Pitzer model, and the calculated solubilities were in good agreement with the experimental values on the whole.