Abstract
The following concentration cell: Fe-Si|CaO-SiO-(Al2O3) (I)|O2|CaO-SiO2-Al2O3 (II)|Fe-Si with ferrosilicon electrodes containing 42%Si was studied at 1,630° Plotting the e.m.f. obtained on the CaO-SiO system against the wt%SiO2, to the reference slag: CaO 45.2 wt%, SiO2 2.2 wt%. Al2O3 53.7 wt%, the curve was characterized by a break which corresponds to CaO. SiO2 composition. The activity of SiO2 on the system CaO-SiO2 was calculated from the e.m.f. by the following equation: −E=RT⁄4FlnSiO2, and the value was compared with the data reported in literatures. Further, iso-activity lines that correspond to the iso-baritic ones observed in the system CaO-SiO-AlO showed considerably complicated figures which might be responsible for the behaviors of Al2O3 in the slags. From this investigaten, it is supposed that the most probable anion species of silica in the studied slags would be SiO44− and SO32−.
