Solubility of TiO2 in NaF-CaF2-BaF2 Melts

The solubility of TiO2 in NaF-CaF2-BaF2 ternary eutectic melts was investigated at the temperature range of 1025–1150 °C. The least-squares equation was obtained from the relationship between the reciprocal temperature and the natural logarithm of the titanium concentration in the melts saturated with TiO2. The corresponding partial molar enthalpy of dissolution of TiO2 was found to be 188 kJ/mol. The titanium saturation concentration was 3.73 wt% at 1100 °C. From the titanium concentration change with the added amount of TiO2 at different holding time after a final stirring, it was found that not only complete dissolution of TiO2 but also enough sedimentation of excessive TiO2 should be guaranteed to obtain more reliable solubility data. The holding time of 10 h was found to be enough for the excessive TiO2 particles to settle down in our experimental conditions. It is noteworthy that in case of adding TiO2 in excess of its solubility, the Ba1.12(Ti8O16) phase was observed at the lower and bottom of the solidified salt ingots.