Electrical Conductivities of Solid and Liquid Cryolite Systems

The electrical conductivities of the NaF–AlF3 cryolite systems with a cryolite ratio 2.4–3.0 containing 3.0–7.0 wt % CaF2, 1.2–2.0 wt % MgF2 and 0–8.0 wt % Al2O3 in the temperature range 700–1050°C are studied by impedance spectroscopy. The addition of CaF2 or MgF2 to molten sodium cryolite decreases the electrical conductivity. However, below the liquidus temperature in the two-phase solid–liquid region the electrical conductivity increases with the fluoride salt concentration. The electrical conductivities of the cryolite systems decrease with increasing Al2O3 concentration over the entire temperature range.