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A glimpse into the mystery of slags — by physicochemical measurements
Seshadri Seetharaman and Lijun Wang
Measurements of the physicochemical properties of slags such as thermodynamic activities and viscosities have been very useful, not only from a process metallurgical view point, but also towards understanding of slag structure, which still remains a mystery. This paper presents some measurements of the slag properties carried out at the Royal Institute of Technology, Stockholm as well as at TU-Bergakademie, Freiberg, Germany that provide a unique insight into the structure of slags. The measurements include sulphide capacities of slags in the region between ortho– and meta– silicate compositions, which could be explained on the basis of the polymerization of silicates. Density measurements of aluminosilicate slags provide an insight into the relative bond strengths. Measurements of the chemical diffusivities have been carried out. This enables an understanding of the affinity of sulphide ions in the molten silicate. The surface velocity and viscosity measurements provide an understanding of the surface bondings between sulphur/ oxygen and Fe atoms. The latest experimental technique developed jointly in Germany and Sweden provides a glimpse into the evaporation phenomena on thin slag films. The need for the application of newer experimental methods in the study of slag properties is emphasized in the present paper.
Keywords: Slags, properties, measurements, structure, phenomena