Influence of slag mineralogy on apparent viscosity in secondary steelmaking

The mineralogy of secondary steelmaking slags contributes in a large part t o the theological characteristics of the melt and, thus, a knowledge of the contribution of slag practice to mineralogy can assist in understanding th e variations in slag theology often encountered between ladle and tundish, Therefore, to evaluate the influence of slag practice on the theological na ture and chemical. mineralogical composition of the various slags used duri ng the life of a heat of steel, ladle and tundish slags were drawn from a t ypical minimill and simulated on a laboratory scale. The rheological and mi neralogical nature of these slags was determined, and related to slag pract ice. Results suggest that slag composition in the tundish, as influenced by carryover from the ladle, the presence of oxygen, and the use of thermal b lanket materials, may contribute to the formation of refractory minerals. T he use of alternative fluxes in place of fluorspar may assist in postponing the formation of such minerals, thereby preventing the onset of unpredicte d rapid solidification either in the ladle or during casting. (C) 2001 loM Communications Ltd.