IN SITU OBSERVATION OF MgO DISSOLUTION IN CaO-Al_2O_3-SiO_2 BASED SLAGS

摘要

The dissolution of magnesia particles in synthetic CaO-Al_2O_3-SiO_2 (CAS) slags with and without MgO addition has been investigated in situ with a Confocal Scanning Laser Microscope (CSLM). The dissolution process was recorded. The effects of slag composition and temperature on the dissolution process and the time dependency of the MgO particle size during dissolution are obtained. Increasing the temperature accelerates the dissolution rate. However, MgO addition to the slag retards the dissolution rate significantly. The rate determining steps are discussed. It is shown that boundary layer diffusion is responsible for the dissolution. Finally, it is revealed that, depending on the experimental conditions, magnesia-alumina spinel can be formed.