THERMODYNAMIC PROPERTIES OF THE NA-K-CA-BA-CL-H2O SYSTEM TO 473.15 K AND SOLUBILITY OF BARIUM-CHLORIDE HYDRATES

Pitzer's ion interaction parameters for aqueous barium chloride are de rived as a function of temperature from published parameter values for the activity coefficient and for the enthalpy at 298.15 K, and by fit ting osmotic coefficients measured by Holmes and Mesmer (J. Chen. Ther modyn. 1981, 13, 1025) to 473.61 K. This allows the calculation of the thermodynamic properties of barium chloride solutions including the B aCl2(aq) activity coefficient and the activity of water. Barium chlori de mono- and dihydrate solubilities in pure water are used to calculat e their solubility products at various temperatures. Solubility, data of barium chloride dihydrate in the Na-K-Ca-Ba-Cl-H2O system are used to calculate Fitter's mixing parameters. It is shown that the solubili ty of BaCl2 . 2H(2)O(s) in this system can be accurately predicted to high concentration using the resulting parameters.