8th International Congress on Science and Technology of Ironmaking - ICSTI 2018

Ironsand is a potential cheap source of iron with possible other values such as titania and vanadium oxide. Direct reduction is regarded as one of the promising processes to deal with ironsand in both an economically and environmentally sustainable manner. In this study, the reduction characteristics of pelletised ironsand ore by hydrogen gas were investigated. The pelletising and sintering of the ore is an oxidation process and results in the ironsand transforming to titanohematite (TTH). A thermogravimetric technique has been used to evaluate the kinetics and X-ray diffraction used to establish the phase distribution before and after the reduction experiments. The experiments were carried out isothermally between 800-1200°C under pure hydrogen. As expected the reduction rate increased with temperature and metallic iron and ilmenite were found in the reduced pellets at all temperatures. At 900°C and below Ti was also present as rutile, while at temperatures >900°C the second Ti bearing phase was pseudobrookite. Attempts to use a simple single interface shrinking core model (SCM) to represent the kinetics proved problematic and did not represent the experimental results well. It is likely that this is a result of the reduction process being more complex than this single interface model. Future work is focused developing a more rigorous approach to the kinetics and establishing the reaction interfaces and composition gradients within the pellet.