Effects of Ilmenite Ore on Phase Development of Hematite Ore Sinter

The effects of adding 5 to 25 wt pct of ilmenite ore to hematite ore sinter were investigated employing a horizontal tube furnace to clarify the phase development. The temperature was raised nonisothermally at 10 degrees C/min to 1150 degrees C in an Ar atmosphere. When the target temperature was reached, 1 L/min of air was injected to allow combustion of the carbon in the pellets. The development of the phases in the sinters was studied using X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), and electron probe microanalysis (EPMA). The tumbler index (TI) decreased with the increase in ilmenite addition up to 20 wt pct, which increases TiO2 (s) and Fe3O4 (s) content in the sinter blends. Addition of more than 2 wt pct TiO2 (s) to the sinter blends resulted in the formation of perovskite (CaO center dot TiO2), which affected the development of bonding phases. These changes deteriorated the reduction degradation index (RDI). The estimated melt formation temperature of the sinter blends increased with ilmenite addition up to 15 wt pct and decreased thereafter. An attempt was made to predict the development of phases in the ternary phase diagram of CaO-Fe2O3-TiO2. The reduction behavior of the sinter blends was affected by the type of the bonding phase.