| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1638898 | Transactions of Nonferrous Metals Society of China | 2011 | 5 Pages |
Raman spectrum of molten cryolite was recorded. Based on the new understanding of the scattering coefficients, contents of various structural entities in acidic NaF-AlF3 melts at 942-1 024 °C in previous research were reanalyzed. The new quantitative analysis results show that when cryolite ratio(CR) is less than 2, AlF4− is the dominant anion in the melts, and its mole fraction is about 0.70 for melts with CR=1.5 and 0.50 for melts with CR=2. When CR is more than 2.5, the mole fraction of AlF63− is relatively large, which is around 0.45 for melts with CR=2.5. Ionic structure of Na3AlF6-Al2O3 melts was investigated by UV-Raman spectroscopy. Octahedral AlF63− and tetrahedral AlF4− are proved to exist with possible partial replacement of F− by O2−. Al2O2F42− with a large scattering coefficient also exists in the melts in which alumina concentration is more than 4% (mass fraction). The increase of temperature causes blue-shift of the bands in the Raman spectra.
