Low-Melting CaCl2-NaCl-Al2O3 Electrolyte for Direct Electrochemical Reduction Solid Al2O3

The electrical conductivity and density of the low-melting CaCl2-NaCl-Al2O3 systems at 550°C~800°C ranges were respectively measured by the Continuously Varying Cell Constant Technique, ac-techniques and Archimedes method. The materials were applied as the electrolyte for the direct electrochemical reduction solid Al2O3 at 550°C ~800°C. The materials were composed of 71wt.%~87wt.%CaCl2 (corresponding NaCl), NaCl and Al2O3(without and saturated). The results showed that additive Al2O3 decreased the electrical conductivity of the materials, and resulted in the increase of activation energy of conductance. The functional relationship between the electrical conductivity and temperature was linear, and conformed to the Arrhenius equation. Increasing the CaCl2 content decreased the electrical conductivity of the materials, but the density was increased. Increasing the CaCl2, the decrease scope of the electrical conductivity was small and the increase trend of the density was slowed down, the influence of increasing the content of CaCl2 in systems on the direct electrochemical reduction solid Al2O3 process is smaller. The temperature was a decisive factor on the electrical conductivity of the electrolytes and electrolysis process.