DENSITY AND SURFACE-TENSION OF SLAG MELTS OF THE SYSTEM FE2O3-FEO-CAO-SIO2

The effect of SiO2 on the density and surface tension of Fe2O3-FeO-CaO -SiO2 slag melts was studied at concentrations of up to 10 wt. % SiO2. The maximum gas bubble pressure method was employed in the measuremen ts. Silica reduces density and surface tension, while increasing the m olar volume and statistically mean she of ions present in the ferritic -lime melt. The results showed that the physical properties of slag sy stems are for the most part influenced by the character of anionic fer ric oxide complex compounds. The Fe3+ cation can form FeO+, FeO2-Fe2O5 4- and FeO45- complex compounds with oxygen while possibly also changi ng oxygen coordination of the iron ions. At the concentrations in ques tion, SiO2 occurs mostly in the form of SiO44- tetrahedrons.