Experimental Phase Equilibria Studies in the FeO-Fe2O3-CaO-SiO2 System in Air: Results for the Iron-Rich Region

New experimental data are reported on the liquidus and sub-liquidus phase equilibria in the FeO-Fe2O3-CaO-SiO2 system in air. The study was undertaken using equilibration/quenching and microanalysis techniques enabling the compositions of the liquid and solid phases in equilibrium at temperature to be accurately measured. The limits of stability and associations of the primary phase fields of hematite (Fe2O3), dicalcium silicate (Ca2SiO4), silico-ferrite of calcium solid solution (SFC), dicalcium ferrite (Ca2Fe2O5), calcium ferrite (CaFe2O4), calcium diferrite (CaFe4O7) have been characterized in the high iron, high CaO/SiO2, low melting temperature region of the system. The full extent of the primary phase field of SFC has been determined, as have the conjugate lines joining the SFC and the corresponding liquid phase over the range of SFC compositions at sub-liquidus temperatures.