Effect of Heating Rate on Carbothermic Reduction and Melting Behavior of Iron Ore-Coal Composite Pellets

In the ironmaking processes via carbothermic reduction with tall-bed reactor, composite pellets are rapidly reduced to highly metallized direct iron (DRI) high productivity under temperature. Without coke making and ore sintering process, not only help broaden selection of raw materials but an environmentally friendly approach for process. this study, experiments were conducted ore-coal four heating rates. During reduction, reaction was quenched at different temperatures by quickly moving specimens room After experiments, we performed phase analysis X-ray diffraction, chemical composition wet method, microstructure observation element distribution scanning electron microscopy energy dispersive spectrum. The pellet morphology during also recorded. fast rates (80°C/min 40°C/min) collapsed over 1300°C. slow rate (20°C/min) maintained their spherical until 1400°C. We found that formation melting fayalite (2FeO–SiO2 or Fe2SiO4) played a key role in collapsing behavior pellets, which can be classified into three stages, (a) between 1000°C 1200°C, large amount compound (melting point 1178°C) formed. (b) above 1178°C, started melt became liquid phase. (c) 1178°C 1400°C, lost strength, due excess present.