Thermodynamics of Fe_tO-TiO₂-SiO₂ melts in equilibrium with solid iron

The activities of Fe_tO in a Fe_tO-TiO₂-SiO₂ system in equilibrium with solid iron at 1 623 and 1 673 K were measured by equilibrating molten slag with a H₂-CO₂ gas mixture. The iso-activity contour of Fe_tO for this system was calculated and influence of slag composition on the activity coefficient of Fe_tO and the Fe³⁺/Fe²⁺ ratio was determined. On the assumption that the Fe_tO-TiO₂-SiO₂ system is based on an ideal mixture of the pseudo-binary components, the activities of SiO₂ and TiO₂ were estimated using Richardson's method.