DENSITIES OF MELTS IN THE FEO-FE2O3-CAO AND FEO-FE2O3-2CAO.SIO2 SYSTEMS

The densities of melts in the systems FeO-Fe2O3-CaO and FeO-Fe2O3-2CaO&middotSiO2 have been measured under controlled oxygen partial pressures from the liquidus temperature to 1873 K by using the Archimedean method. The molar volumes of melts in the ternary system FeO-Fe2O3-CaO satisfy the additive rule. The molar volume of hypothetical liquid lime in iron oxide melts shows good agreement with that estimated from CaF2-CaO melts and from SiO2-CaO melts. The densities of the FeO-Fe2O3-CaO melts, ρ (kgm-3) can be reproduced to within ±0.5% by equations. For the melts in the system FeO-Fe2O3-2CaO&middotSiO2, the molar volumes do not satisfy the simple additive rule. Increase of dicalcium silicate content and ferrite ions in the melt may contribute to polymerization of silicate ions, and results in a positive deviation from the additive rule in volume. A liquid miscibility gap was observed in the system FeO-Fe2O3-2CaO&middotSiO2.