Experimental Investigation of the Viscosities in CaO-SiO₂-MgO-Al₂O₃ and CaO-SiO₂-MgO-Al₂O₃-TiO₂ Slags

The viscosities of high alumina blast furnace slags were experimentally determined by the rotating cylinder method using the Brookfield digital viscometer model LVDV-II+ pro. Two different slag systems were considered for the current study, the CaO-SiO₂-MgO-Al₂O₃ quaternary and the CaO-SiO₂-MgO-Al₂O₃-TiO₂ quinary system. Experiments were conducted in the temperature range of 1650 to 1873 K. The effects of temperature, basicity, TiO₂, and silica activity of slags on viscosity were studied. The viscosity decreases with basicity for high alumina blast furnace slags with basicity in the range of 0.46 to 0.8. At high basicity (∼0.8), slag viscosity decreases even with a small amount of TiO₂ (∼2 pct) addition in the slag. With an increase in silica activity in the range of 0.1 to 0.4, the slag viscosity increases, the increases being steeper below the liquidus temperature.