Studies on kinetics of iron oxide reduction

Abstract

AbstractThis paper is a review of the iron-oxide reduction research that has been in progress for some years at the University of Toronto. Emphasis has been directed toward the kinetics of hydrogen reduction of sintered briquettes made from reagent-grade iron oxide with and without small additions of impurities. For simulation of hematite ores, the ferric oxide was used directly while the same material, reduced to magnetite, was used to simulate magnetite ores.It was found that hematite reduced in a topochemical manner, and that the reduction rate increased with temperature. For magnetite, a pronounced rate minimum was observed around 700°C at which the briquettes reduced uniformly throughout, leaving grains of unreacted wustite in the iron product. A topochemical pattern of reduction was observed at higher and lower temperatures. Some impurities eliminated the rate minimum.The rate mmimum has been singled out for special study and it has been established that it is controlled by solid-state diffusion in ...