Thermodynamics Research Center / ThermoML | Journal of Chemical and Engineering Data

ABSTRACT

The solid liquid equilibria in the ternary system CaBr2 MgBr2 H2O and quaternary system NaBr KBr SrBr2 H2O at 348 K were determined with the method of isothermal solution saturation. Also determined are the densities of saturated solutions. The phase diagram of the ternary system CaBr2 MgBr2 H2O has two invariant points, three univariant curves and three crystallization fields (which are saturated with MgBr2*6H2O, 2CaBr2*MgBr2*12H2O, and CaBr2*2H2O, respectively). The phase diagram of the quaternary system NaBr KBr SrBr2 H2O includes one invariant point, three univariant curves and three crystallization fields (which are saturated with SrBr2*6H2O, NaBr, and KBr, respectively). On the basis of the extended Harvie Weare (HW) model and its temperature-dependent equation, the mixing ion interaction parameters ?Mg,Ca, ?Mg,Ca,Br and the dissolution equilibrium constant K for MgBr2*6H2O, CaBr2*2H2O, and 2CaBr2*MgBr2*12H2O in the ternary system at 348 K were fitted by using the Pitzer equations and the multiple linear regression method. A chemical model was constructed to calculate the solubility curves by using the Pitzer equations in the ternary systems MgBr2 CaBr2 H2O at 348 K. The calculated solubilities are in agreement with experimental data.