Determination of Relationship between Autoignition of Sponge Iron and Specification of the Iron Ores

Sponge iron (DRI) due to the high surface area, often shows a high tendency to re-oxidation and at some cases spontaneous combustion (autoignition). In this work, re-oxidation behavior and autoignition of sponge iron, produced from different types of iron ore has been investigated. Isothermal and non-isothermal re-oxidation experiments were carried out on each type of DRI and their autoignition temperature was determined. Microscopic examination and porosimetric measurements also were used to elucidate the relationship between the DRI specification and its re-oxidation behavior. The type and chemical analysis of the iron ore, used for the production of DRI, had a strong influence on the microstructure of sponge iron and, in turn, on its sensitivity to re-oxidation and autoignition.