Kinetics and mechanism of reoxidation behavior of solid reductant based direct reduced iron

Abstract

Direct Reduced Iron (DRI), a product of solid state reduction of iron ore lump or pellets, has large inner surface or extended surface and is highly pyrophoric. Unless suitable antiactivation or passivation treatment is given, under unfavourable chemical condition, it undergoes accelerated corrosionloxidation both at room as well as elevated temperature. In addition to losses in metallization which result in rendering the DRI unsuitable for its end use, the accom-panying evolution of heat due to oxidation, can cause significant increase in temperature resulting in faster oxidation and even producing true ignition leading to fire hazards. The work envisages the study of kinetics of reoxidation of DRI by basically two different processes of reoxida-tion : (1) Corrosion with participation of outdoor pollu-ted atmospheric oxygen and indoor atmospheric oxygen. (2) Elevated temperature oxidation with participation or pure oxygen and atmospheric oxygen. The mechanism of reoxidation of DRI is discussed.