The reduction of magnetite and lean magnetite sinters.

The problems encountered in at tempt.ing to determine the rate controlling step in the reduction of magnetite end sinters to iron are revealed by a survey of the pertinent literature. On the basis of previous work supplemented by the investigations reported in this thesis the probable sequence of rate controlling steps has been determined. Exhaustive metallographic and mathematical studies have been carried out on the hydrogen reduction of magnetite and lean magnetite sinter samples reduced in thermal balances.The existence of rate minima at 650°C and 900°C in the reduction of magnetite has been shown by metallographic techniques. Additionally the extent of chemical reaction and mass transport control has been shown by mathematical studies. Similarly the extent of chemical and transport control in sinter reduction has been shown metallographically and mathematically. The effect of thermal treatment in oxidising and inert atmosphere has been shown. The improvement in reaction rates as a result of particular thermal treatments has been displayed.