Liquidus temperatures, obtained by quenching technique, were measured for mixtures in the system CaO-SiO2-Al2O3-Fe3O4in 10-7 atm atmosphered PO2. Analysis of final silicate slag of sintered are by use of EPMA revealed that chemical compositions lay in the field near the pseudowollastonite-dicalcium eutectic line between 1 250°C and 1 300°C in the phase diagram.
An interrupted sintering pot test and sintering simulation experiments of the mixture of raw materials showed that there were two kinds of primary melts, which were liquid silicate and liquid calcium ferrite. Liquid calcium ferrite generated two kinds of structures; one consisted of quarternary calcium ferrite and silicate slag, and the other was mainly composed of dicalcium silicate and dicalcium ferrite or magnetite.
With increasing temperature, primary silicate melt of low basicity dissolves dicalcium silicate and becomes final slag of higher basicity.
