LAUSR

The form and concentration distribution of anions in a molten KF-AlF3 system with different molar ratios (1.5–8) at different temperatures were analyzed with Raman spectroscopy. The results indicate that for molar ratios in the range of 1.5–5, AlF63−, AlF52−, AlF4−, and F−, were all present in the system, while for molar ratios in the range of 6–8, only AlF63−, AlF52−, and F−, were present. For molar ratios in the range of 1.5–2.5, the AlF52− ion content was the most sensitive to temperature among all the complex ions in the system, whereas for molar ratios in the range of 4–8, minor variations in the constituent anion contents were observed as a function of temperature. The Al3+ ions in the system with the molar ratios of 1.5–5, 6, and 7 or 8 tended to form AlF4−, AlF52−, and AlF63−, respectively, as the temperature increased.