The reactions of powdery ferric oxide mixed with graphite particles in the stream of nitrogen were carried out at 1O5O-115O°C. The overall reduction process of ferric oxide to metallic iron proceeded through two stages.
In the first stage, ferric oxide was reduced to magnetite and then to ferrous oxide by carbon monoxide, yielding carbon dioxide. Carbon monoxide is produced by reaction between graphite and carbon dioxide (carbon solution reaction), which seems to control the rate of overall reaction.
In the second stage occur the reduction of ferrous oxide to iron and the carbon solution reaction. This stage of the reaction can be assumed to proceed autccatalytically and is greatly influenced by the size of ferric oxide and addition of bentonite.
Effects of the particle size, addition of bentonite and contact condition of particles on the rate of overall reduction are discussed.