SURFACE TENSION AND DENSITY OF FeO-CaO-SiO2 MELTS.

Abstract

The surface tension and density of FeO-CaO, FeO-SiO//2, and FeO-CaO-SiO//2 melts, with CaO contents up to 40 mol% and SiO//2 up to 50 mol%, in contact with solid iron were measured at temperatures from melting points to 1430 degree C by the maximum bubble pressure method. Surface tension values of these melts range from 350 to 530 dyn/cm. Surface tension values of these melts ranged from 350 to 530 dyn/cm. Surface tension and density of liquid iron oxides show an abnormal behavior, that is, a positive dependence on temperature. The additon of CaO or SiO//2 to iron oxide lead to monotonous decreases of surface tension and density of melts, but the maximum of surface tension is observed in the isothermal curve of surface tension of FeO-CaO-SiO//2 ternary melts of constant CaO content of 1400 degree C. It is found that surface tension values of melts calculated from the equation containing terms of surface tension coefficients and the effect of ferric oxide agree well with the experimental results in the composition range investigated. Molar volumes of FeO-CaO and FeO-30CaO-SiO//2 melts show negative deviations from ideal mixture of components.