The Surface Tensions and Foaming Behavior of Melts in the System CaO-FeO-SiO2

The surface tensions of melts in the system CaO-FeO-SiO2 have been measured in the temperature range 1573 to 1708 K using the hollow cylinder technique. The iron oxide content was maintained constant at 30 wt pct and the CaO/SiO2 wt pct ratio was varied in the range 0.43 to 1.5. Surface tension increases with increasing basicity and with decreasing temperature. The data were used to test published correlations of slag foaming indexes with surface tension and viscosity. Foam life increases with increasing viscosity and with decreasing surface tension.