Density, Viscosity and Electrical Conductivity of the Molten Cryolite Electrolytes (Na 3 AlF 6 –SiO 2 ) for Solar Grade Silicon (Si–SoG) Electrowinning

Density, viscosity and electrical conductivity of the molten system Na 3AlF 6–SiO 2 have been investigated in the concentration range up to 50 mole % of SiO 2. Density was measured by means of a computerized Archimedean method, viscosity of the melt by computerized torsion pendulum method and the electrical conductivity by means of the tube–cell (pyrolytic boron nitride) with stationary electrodes. It was found that the density, viscosity and conductivity vary linearly with the temperature in all investigated mixtures. On the basis of the density data, the molar volume of the melts and the partial molar volume have been calculated.