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

Abstract

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.