A study of the dissolution of Al2O3, MgO and MgAl2O4 particles in a CaO-Al2O3-SiO2 slag

The dissolution behaviour of alumina, MgO and MgAl 2 O 4 particles in a 36%CaO-21%Al 2 O 3 -42%SiO 2 (mass contents in %) slag has been studied using a confocal scanning laser microscope in the temperature range of 1470- 1550 °C. The double hot thermocouple technique and metallographic examination was also used to characterize the reaction product between the particles and the slag. The total dissolution times for MgO and MgAl 2 O 4 particles decreased with increased temperature and were almost identical (approximately 200 s for a 150 μm diameter particle at 1500 °C.). This phenomenon can be explained by the formation of MgAl 2 O 4 layer on the surface of the MgO particle during dissolution. Alumina dissolution times were slightly longer (approximately 250 s for a 150 μm diameter particle at 1500 °C) than that of MgO and MgAl 2 O 4 particles and no reaction layer was observed on the surface of the particles.