Influence of slag mineralogy on apparent viscosity in secondary steelmaking

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