Solubility of Al2O3 in some chloride-fluoride melts.

Alumina solubility in chloride-fluoride melts of KCl-NaCl-NaF mixtures with ratios of 0.425:0.425:0.15 (I), 0.38:0.38:0.24 (II), and 0.35:0.35:0.30 (III) (molar fractions) was investigated in the 973-1123 K temperature range using the isothermal saturation method. Al2O3 solubility in the ionic melts studied was shown to be on the order of 0.06 g kg(-1) for system I, 0.12 g kg(-1) for system II, and 0.14 g kg(-1) for system III at 1073 K. All the "Al2O3 + melt" systems were found to demonstrate negative deviations from the ideal solutions. The solubility of Al2O3 in all the melts increases with the temperature increase; however, the dependences of -log N(Al2O3) versus T(-1) were characterized by the slopes (2.6 +/- 0.4) x 10(3) K (I and II) and (2.4 +/- 0.6) x 10(3) K (III), which were considerably less than the slope predicted by the Shreder-Le Chatelier equation (approximately 5.8 x 10(3)).