Experimental in situ Raman spectra are presented for potassium, sodium and mixed fluoroaluminate melts. More acidic melts with cryolite ratio (CR) below 2 are accented. The cation-dependent ratio of integral band intensities is assigned to specific interactions of potassium cations with low coordinated fluoroaluminates. For alumina containing melts, the effect of potassium on the stoichiometry of predominating oxofluoroaluminate anion is observed indirectly. Density functional theory is employed to investigate the behavior of different fluoroaluminates (including dimers) and their associates formed by alkali metal cations.
- Modelling of ionic species
- Raman spectroscopy
- Sodium and Potassium cryolite