Viscosity of low silica CaO–5MgO–Al 2 O 3 –SiO 2 slags

The viscosity of CaO–5MgO–Al2O3–SiO2 slag with low silica was measured by rotating cylinder method up to 1823 K. Slag compositions were chosen based on five different levels of SiO2 content between 0 and 11·80%. The MgO content was 5·0%. The mass ratio of CaO/Al2O3 was varied from 0·66 to 1·95. It was shown that viscosity decreased with increasing temperature and decreased with increasing the mass ratio of CaO/Al2O3, following by an increase with further increasing the mass ratio of CaO/Al2O3. The viscosity decreased with the NBO/T ratio increasing, and the trend that flow activation energy changes with the NBO/T ratio of slag was the same as the trend that viscosity changes with the NBO/T ratio. Based on the experimental data as the boundary of the homogenous phase region, the mass triangle model was used to calculate the viscosity of low silica region.