Analysis of Retardation Phenomenon in Iron Ore Reduction by Three-Interface Model with Solid-State Diffusion Step

Abstract

In order to investigate the retardation phenomenon in iron ore reduction, fine ore particles were reduced with Hydrogen gas in the temperature range from 650°C to 850°C by microbalance technique. Many unreacted wüstite particles, of which diameter is 0.58 μm-0.76 μm, surrounded by dense iron were micrographically observed in a sponge iron. Three-interface model combined in series with solid-state diffusion step can simulate very well reduction curve involving retardation period. Permeability of oxygen obtained by parameter-fitting method is in the range of 5.3×10^-14g/cm s-1.6×10^-12 g/cm s at 650°C-850°C, which results coincide with previously reported data within a range of one order.