DENSITY AND SURFACE-TENSION OF FE2O3-FEO- CAO-ZNO OXIDIC MELTS

The influence of up to 35 mol. % ZnO at 1573 K on the density and surf ace tension of Fe2O3-FeO-CaO-ZnO slag melt was studied by the method o f maximum bubble pressure. The higher is the ZnO concentration in the system, the higher is the melt density and surface tension when calciu m and ferric oxides are substituted. Molar volume and average size of ions in the melt decrease. The theory that the physicochemical propert ies of ferritic-calcium slag systems are affected mainly by the charac ter of iron oxide anion complexes has been proved by the present exper imental results. The Fe3+ cation can create a complex with oxygen anio ns, like FexOyz-, in ferritic-calcium melts and also the coordination of Fe ions with oxygen gradually changes from octahedral to tetrahedra l. We assume that the Zn atoms are dissociated to Zn2+ and O-2(2-) in ferritic-calcium slags.