Separation and dissolution of Al2O3 inclusions at slag/metal interfaces

To achieve better process control and product quality in clean steel manufa cturing, it is necessary to understand the underlying processes behind (i) separation of inclusions across slag/metal interfaces and (ii) dissolution of the inclusions in the slag. This paper presents results on both these pr ocesses obtained through in situ observations with a confocal scanning lase r microscope (CSLM) at steelmaking temperatures. In the case of inclusion s eparation, it was found that liquid inclusions could be observed to separat e across the slag/metal interface and dissolve. Solid Al2O3 inclusions, how ever, were observed at the slag side of the interface and could be seen to agglomerate. The dissolution rate of slag particles was found to be a funct ion of slag chemistry and temperature and to be controlled by diffusion in the liquid slag. (C) 2001 Published by Elsevier Science B.V.