Dissolution rate of sintered alumina in molten CaO-SiO2-Al2O3 slags

Dissolution rates of sintered alumina in molten CaO-SiO2-Al2O3 slags at 1793, 1828 and 1863 K were measured by the rotating disk method. The alumina contents of the slag were 10, 20, and 30%, and the CaO/SiO2 ratio was 1. The dissolution rate of alumina was linearly related to the square root of the specimen rotation rate. This result suggested that the dissolution process was controlled by mass transfer in the boundary layer of molten slag. The dissolution rate decreased with increasing alumina content of the slag, and the diffusion coefficient of alumina was almost unchanged. The decrease of the dissolution rate was due mainly to a decrease of the driving force. The dissolution rate and the diffusion coefficient of alumina increased with rising temperature. The increase of the dissolution rate was due mainly to the increased alumina diffusion coefficient.