Comparative study of oxide inclusion dissolution in CaO-SiO2-Al2O3 slag

The dissolution of alumina, spinel and zirconia inclusions in a liquid CaO-SiO2-Al2O3 slag has been investigated using laser scanning confocal microscopy. Over the experimental temperature range 1477-1577 degrees C it is found that alumina inclusions have a slower dissolution rate than that of spinel, and that zirconia inclusions form gas bubbles at the inclusion surface during dissolution. The results have been analysed assuming mass transfer control in the slag phase, and the slower rate of dissolution of the alumina inclusions is explained by the observation that they have a greater mass of aluminium oxide, the rate controlling species, than that of spinel.