2017 Volume 57 Issue 6 Pages 983-988
Operational smoothly of ironmaking process is determined to a great extent by its slag performance especially for the large blast furnace. Operation characteristic of super-large blast furnace slag in China was summarized and the appropriate adjustment measures for better performance of BF were analyzed based on the operation characteristic by using the MPE. The results show that MgO content ranges from 6.5–9.5 wt% and Al2O3 ranges in 11–16 wt% of the super-large blast furnaces. The hot metal temperature ranges between 1490–1520°C and C/S is controlled within 1.12 to 1.24. A slag operation concept is built for reference by the operation viscosity and the superheat temperature. The operation viscosity is 0.34±0.02 Pa·s and the superheat temperature is 80±10°C. Based on this, Mg/Al ratio can be reduced with the increasing C/S in the production. Mg/Al ratio of 15 wt% Al2O3 slag can be reduced to 0.4 in the high basicity of 1.3 and should be increased to 0.67 in the low basicity of 1.1. Mg/Al ratio of 0.53 (8 wt% MgO) is ideal if the basicity of slag changes in a wide range near 1.2. The rational Mg/Al ratio of the slag (C/S=1.2) can be reduced to 0.33, 0.47 and 0.58 when the Al2O3 in the slag are 12 wt%, 15 wt% and 18 wt%, respectively.