INFLUENCES OF MGO ON ROASTING PROPERTIES OF OXIDIZED IRON ORE PELLETS

The roasting properties of oxidized iron ore pellets, such as mechanical strength, roasting temperature and remnant of FeO, are affected by adding MgO. As the content of MgO was increased, the strength of roasted pellets was decreased, the zone of suitable roasting temperature was narrowed, and the FeO content of pellets roasted at high temperature was increased. Through analysis of microstructure and spectrum characteristics, two primary mechanisms were observed explaining the effects of MgO on the roasting behavior of iron ore pellets. In the case of magnetite, MgO forms a solution, while in hematite, MgO reacts to form magnesioferrite. Both of these observations are in agreement with solid state reaction theory and predictions from phase diagrams.