Influence of original structure on the kinetics and mechanisms of carbon monoxide reduction of hematite compacts.

Abstract

Green, porous and dense Fe203compactshaving 54, 35 and 8 / porosity respectively were obtained at different tem- peratures. Thestructure of these compacts was examinedand correlated to their thermal history. Thesecompacts were isothermally reduced with carbon monoxide at 500-1 100'C using weight-loss technique. The structural changes accompanyingthe reduction process were examinedwith mercury pressure porosimeter and with optical and scanning electron microscopes while the different phasesformed during reduction was identified by X-ray ditfraction 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 Y-iron.