Dissolution behavior of SiO 2 in the molten blast furnace slags

The kinetics of SiO 2 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 Al 2 O 3 on the SiO 2 dissolution were clarified in this study. The experiment results showed that the dissolution process is controlled by the solute diffusion in the slag. The SiO 2 dissolution rate could be accelerated by increasing the temperature. Moreover, the SiO 2 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 SiO 2 dissolution rate is the fastest in the slag with 18.0 pct Al 2 O 3 when the Al 2 O 3 varies between 14.0 and 20.0 pct. The effects of temperature, MgO and Al 2 O 3 on the SiO 2 dissolution rate could be indicated by a simple expression ( c sat −c b )/ η that a larger of ( c sat −c b )/ η is associated with the faster SiO 2 dissolution rate, where ( c sat −c b ) is the difference between the concentration of SiO 2 in the saturated slag and in the bulk of slag, and η is the slag viscosity.