Dissolution behavior of SiO2 in the molten blast furnace slags

Abstract

AbstractThe kinetics of SiO2 dissolving in the molten blast furnace slags at 1743‐1803 K was studied using a High Temperature Confocal Scanning Laser Microscopy (HT‐CSLM), and then the effects of temperature, MgO and Al2O3 on the SiO2 dissolution were clarified in this study. The experiment results showed that the dissolution process is controlled by the solute diffusion in the slag. The SiO2 dissolution rate could be accelerated by increasing the temperature. Moreover, the SiO2 dissolution rate is the fastest in the slag with 11.0 pct MgO when the MgO varies between 7.0 and 13.0 pct. The SiO2 dissolution rate is the fastest in the slag with 18.0 pct Al2O3 when the Al2O3 varies between 14.0 and 20.0 pct. The effects of temperature, MgO and Al2O3 on the SiO2 dissolution rate could be indicated by a simple expression (csat−cb)/η that a larger of (csat−cb)/η is associated with the faster SiO2 dissolution rate, where (csat−cb) is the difference between the concentration of SiO2 in the saturated slag and in the bulk of slag, and η is the slag viscosity.