Investigation of physicochemical and technological properties of sodium tetrafluoroaluminate

Physicochemical properties of condensed sodium tetrafluoroaluminate are investigated by methods of thermogravimetry, high-temperature X-ray phase analysis, and thermodynamic calculations of the phase diagram of the NaF-AlF₃ system. It is shown that it is possible to use this compound as a correcting additive to electrolyte in aluminum electrolyzers instead of the mixture of cryolite and aluminum trifluoride. This replacement allows one to reduce the consumption of fluorine salts, to optimize the balance of production components, and to make aluminum production more environmentally friendly.