Viscosity Measurements of “FeO”-SiO₂ Slag in Equilibrium with Metallic Fe

The current study delivered the measurements of viscosities in the system “FeO”-SiO₂ in equilibrium with metallic Fe in the composition range between 15 and 40 wt pct SiO₂. The experiments were carried out in the temperature range of 1473 K to 1773 K (1200 °C to 1500 °C) using a rotational spindle technique. An analysis of the quenched sample by electron probe X-ray microanalysis (EPMA) after the viscosity measurement enables the composition and microstructure of the slag to be directly linked with the viscosity. The current results are compared with available literature data. The significant discrepancies of the viscosity measurements in this system have been clarified. The possible reasons affecting the accuracy of the viscosity measurement have been discussed. The activation energies derived from the experimental data have a sharp increase at about 33 wt pct SiO₂, which corresponds to the composition of fayalite (Fe₂SiO₄). The modified quasi-chemical model was constructed in the system “FeO”-SiO₂ to describe the current viscosity data.