Abstract
Green, porous and dense Fe2O3 compacts having 54, 35 and 8% porosity respectively were obtained at different temperatures. The structure of these compacts was examined and correlated to their thermal history. These compacts were isothermally reduced with carbon monoxide at 500-1100°C using weight-loss technique. The structural changes accompanying the reduction process were examined with mercury pressure porosimeter and with optical and scanning electron microscopes while the different phases formed during reduction was identified by X-ray diffraction technique. At the initial stages of reduction, the rate was increased with temperature and with increase in original porosity of compacts. With progress of reduction, a reduction rate minimum was observed at 950-975°C and was attributed to sintering and densification of γ-iron. The retardation in the rate was not detected during the reduction of dense compacts due to the disintegration of iron grains resulting from carbon deposition and subsequent reactions. The values of apparent activation energy were calculated and correlated with both the original structure of compacts and the reduction mechanisms.
