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

The dissolution behaviour of alumina, MgO and MgAl2O4 particles in a 36%CaO -21%Al2O3-42%SiO2 (mass contents in %) slag has been studied using a confoc al scanning laser microscope in the temperature range of 1470-1550 degreesC . The double hot thermocouple technique and metallographic examination was also used to characterize the reaction product between the particles and th e slag. The total dissolution times for MgO and MgAl2O4 particles decreased with increased temperature and were almost identical (approximately 200 s for a 150 pm diameter particle at 1500 degreesC.). This phenomenon can be e xplained by the formation of MgAl2O4 layer on the surface of the MgO partic le during dissolution. Alumina dissolution times were slightly longer (appr oximately 250 s for a 150 mum diameter particle at 1500 degreesC) than that of MgO and MgAl2O4 particles and no reaction layer was observed on the sur face of the particles.