Phase equilibriums in BaO–BaCl2–KCl–NaCl system

E. V. Nikolaeva, А. L. Bovet, I. V. Коrzun


solubility, thermal analysis, liquidus temperature, barium oxide.


Thermal analysis was applied to determine the liquidus temperatures in the NaCl–KCl–BaCl2–BaO system. The results are adduced as the dependence of liquidus temperatures on the added barium oxide concentration. At first, the BaO additions decrease the temperature of initial crystallization and then increase it.
The BaO solubility was defined as a temperature function; the thermodynamic solubility parameters were calculated. The value of the abundant changes in Gibbs energy of mixing of liquid overcooled oxide and a solvent-melt is slightly negative, which denotes the exothermic interaction between barium oxide and solvent particles at their mixing. The performed studies of caloric effects at melting of chloride eutectic with barium oxide additions testified our thermodynamic calculations and proved the chemical mechanism of barium oxide dissolution in molten chloride eutectic. The X-ray patterns of frozen fusion after the experiment illustrate that Ba4OCl6 is present in the solid phase.
The obtained data may be used to choose reaction media for high temperature technological processes.