Rate Enhancement of the Gaseous Reduction of Iron Oxide Pellets by Pressure Cycling

Abstract

The effect of carrying out gaseous reduction of iron oxide under external pressure cycling has been investigated. When the reduction is carried out at 800°C with pellets of 30% porosity, relatively moderate pressure cycling with an amplitude of 0.5atm and frequency of 0.5cps can lead to about 25% higher reduction within 20min from the start of reaction. A threefold improvement in initial conversion rate can be obtained if higher amplitude and frequency of cycling are used. Computation shows that, for pellets and naturally occurring hematite ore, viscous flow effects can be neglected.
The results of the investigation provide justification for further research in the use of external pressure cycling to overcome diffusional resistances in gas-solid reaction systems.