Oxidation of Flash Reduced Iron Particles in Various Gas Mixtures Under the Conditions of a Novel Flash Ironmaking Process

A novel flash ironmaking process that directly reduces iron oxide concentrate particles by gas is under development. The goal of this work was to study the possibility of reoxidation of iron particles in various gas mixtures. As the product iron cools down in the lower part of the flash reactor, conditions may become favorable for reoxidation because of equilibrium and high reactivity of iron particles. The effects of temperature (823 – 973 K) and H₂O partial pressure (40 – 100 pct., P_total = 86.1 kPa) on the reoxidation rate were examined. The pressure dependence was first order with respect to water vapor, and the activation energy was 146 kJ/mol. A complete rate equation that adequately represents the experimental data was developed. For oxidation in O₂-N₂ mixtures, the effects of temperature (673 – 873 K) and O₂ partial pressure (5–21 pct., P_total = 86.1 kPa) were determined. Reoxidation in pure CO₂ was also investigated at 873 – 1073 K for comparison.