2004 Volume 44 Issue 12 Pages 2052-2056
Effects of adding SiO2 or Al2O3 on the wetting and penetration characteristics of calcium ferrite melts, CaO·Fe2O3 (CF) and CaO·2Fe2O3(CF2), to sintered hematite substrate have been examined. And the wetting and penetration characteristics were discussed from the viewpoints of the relation to the viscosity and surface tension of calcium ferrite melts. The effects of the addition of calcium ferrite slag with SiO2 or Al2O3 on the strength of sintered hematite pellets were also examined.
The slag tablets of CF2-based slag neither melt completely nor spread uniformly on the hematite substrate at the experimental temperature at 1300°C in this study. The wettability of CF-based slag melts on sintered hematite substrate was improved by the addition of SiO2 or Al2O3, and the spreading rate was increased with increasing the value of η/γ (viscosity/surface tension of slag melts). The penetration of CF-based slag melts into sintered hematite substrate was depressed by the addition of SiO2 or Al2O3, and the penetration depth was increased with increasing the value of η/γ surface tension/ viscosity of slag melts). The sintered hematite pellet with CF-5 mass%Al2O3 slag sintered at 1200°C had the highest compressive strength in this study. Because the liquidus temperature of CF slag is decreased to about 1200 °C by adding 5 mass% Al2O3, and the sufficient amount of liquid phase, which has the appropriate wetting and penetrating characteristics controlled by the surface tension and the viscosity, as a binder was formed.