INTERFACIAL TENSION BETWEEN MOLTEN IRON AND SLAGS
Kazumi Mori, Tadato Fujimura
A method for determining the interfacial tension between the molten iron and the slag was established. It consists of photographing the sessile drop of the molten iron by X-ray, measurement of the dimensions of the drop by means of a microcomparater and calculating the interfacial tension using the Bashforth-Adams table. The drop was placed on the horizontal bottom of an alundum crucible, in which the slag was melted. Values of the interfacial tension of the Hg-H2O and Hg-benzene systems calculated by this "Sessile drop method" were in agreement with those reported in literatures. Interfacial tensions between liquid Fe-Si alloy(Si 14·34%)and the slag systems Na2O-SiO2 and Li2O-SiO2 were measured at 1370°C. The values of the interfacial tension were of the order of 1000-1150 dyne/cm, and decreased with increase of the alkali-metal oxide. It was suggested that Na+ and Li+ had the tendency to be adsorbed more easily at the meta1-slag interface than silicate anions.
Assuming the surface tension of the Fe-Si(Si 14·34%)alloy, it was presumed that the values of the work of adhesion of the present systems were of the order of 500-700 erg/cm2, which were approximately in agreement with those of the systems consisting of metals (Ni Fe, Si)and oxide(Al2O3), determined by Humenik and Kingery. Furthermore, it was indicated that the work of adhesion increased with enhancement of Na2O and Li2O.