Electric Conductivity of TiO₂-Ti₂O₃-FeO-CaO-SiO₂-MgO-Al₂O₃ for High-Titania Slag Smelting Process

The electric conductivity of high-titania slag of TiO₂-Ti₂O₃-FeO-CaO-SiO₂-Al₂O₃-MgO slag system was measured by means of four-electrode alternating current (AC) impedance method. The results show that high-titania slag exhibits a good electric conductivity, around 45 to 141 S cm⁻¹ with slight dependence on the temperature, which is of several orders of magnitude higher than that of the silicate slags. Further, electric conductivity of high-titania slag decreased with the increasing FeO content, whereas, the increasing Ti³⁺/Ti⁴⁺ and TiO₂ contents caused a significant increase in the electric conductivity. Based on the experimental results and the calculated results, the conductive mechanism of high-titania slag was discussed in detail. It can be concluded that the high-titania slag exhibits a characteristic of electronic–ionic mixed conductivity, but the effect of electronic conduction dominates above the liquidus temperature; however, with the decreasing temperature, the electronic conductivity was gradually weakened. The mechanism was postulated to be a random walk of electrons between tetravalent titanium and trivalent titanium dispersed in the melt.