Phase-Diagram Study for the Al2O3-CaF2-SiO2 System

Phase relations for the Al2O3-SiO2 system were investigated from 1673 to 1723 K. The hotfilament technique was applied to observe a two-liquid region and liquidus for the ternary system. The liquidus saturated with SiO2 was investigated at 1673 K by using the hot-filament technique and the chemical equilibrium technique. In this system, the addition of Al2O3 to the CaF2-SiO2 system reduces the congruent temperature. A small substitution of Al2O3 for CaF2 increases the solubility of SiO2, namely, if the region of liquid phase could be enlarged. These results suggest that Al2O3 would be an effective substitute of CaF2 in slag for steelmaking.