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

Viscosities of the synthetic slags have been measured at the temperature range of 1423 K to 1773 K (1150 °C to 1500 °C) in the SiO₂-“FeO”-CaO system in equilibrium with Fe. The rotational spindle technique was employed in the measurements using molybdenum crucibles and spindles. Analysis of the quenched sample by electron probe X-ray microanalysis after the viscosity measurement enables the composition and microstructure of the slag to be directly linked with the viscosity. Effects of CaO and “FeO” on viscosity have been compared at different SiO₂ concentrations. It was found that at low SiO₂ concentration, the viscosities increase with the increasing CaO/“FeO” ratio. At high SiO₂ concentration, the viscosities first decrease and then increase with the increasing CaO/“FeO” ratio. The activation energies increase with the increasing CaO/“FeO” ratio. The modified Quasi-chemical viscosity model has been further optimized in this system using the new viscosity measurements.