THE SOLUBILITY OF SNO2 IN NAF-ALF3-AL2O3 MELTS

NaF-AlF3-Al2O3 melts were saturated with SnO2 and analyzed for tin by X-ray fluorescence. The solubility of SnO2 increased with decreasing A l2O3 concentration and increased with increasing temperature, and it s howed a maximum at a NaF/AlF3 molar ratio (CR) of 3. Model fitting sho wed that the most likely dissolved species was SnO2AlF63-, and below c a. 1 wt% A1(2)O(3) the oxyfluorides SnOF42- and Sn2O2F84- were predomi nant. It was also found that the solubility of SnO2 increased with dec reasing oxygen partial pressure over the melts, indicating the formati on of divalent tin species.