The Effect of Alumina Activity on Dissolution Behavior of Alumina Particles in CaO-Al2O3-SiO2 Slags

This study investigated the dissolution of Al2O3 particles in CaO-Al2O3-SiO2 slag by the single hot thermocouple technique (SHTT) in the temperature range between 1550 degrees C and 1650 degrees C. The Al2O3 content in slags with basicity (CaO/SiO2 ratio) fixed at 1 varied from 5 to 35 pct. The evolution of the particle radius over time was obtained by image analysis. In the results of our experiments, the dissolution rate of the Al2O3 particles was increased with increasing Al2O3 activity in the slag. The rotation of the particle was observed during the dissolution experiment. We used a kinetic model that considered the fluid flow to understand the dissolution phenomenon. We calculated the diffusion coefficient of Al2O3 from 10(-13) to 10(-10) m(2)/s and in a similar manner as in a previous study. The activation energy of Al2O3 was 323 kJ/mole at 5 wt pct Al2O3, 343 kJ/mole at 20 wt pct Al2O3, and to 486 kJ/mole at 35 wt pct Al2O3.