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Sponge iron (DRI) as a virgin raw material is of great interest due to developments in producing high quality flat products with low tramp elements content in scrap-based steel making. Sponge iron may react with water and air to produce hydrogen and heat. The heat produced may cause ignition. Precautions are necessary to avoid hazards in transport and storing.

At RWTH Aachen, fine ore was used as a model substance investigating the influence of the gas composition and reduction temperature on the ignition of DRI (Direct Reduced Iron). At the MPIE, the kinetics of reoxidation of direct reduced iron was investigated by thermogravimetry in dependence on temperature and partial pressures of oxygen, water vapour and carbon dioxide. The effects of vapour phase inhibitors were also studied.

Trials carried out in a test-rig showed that a low porosity of the DRI and a high reduction temperature are the main factors for limiting the risk during the transportation of the DRI. Corrosion trials carried out on small DRI samples in a programmable climatic chamber did not assess correctly the reoxidation behaviour of DRI. The reoxidation rate at low temperature <200°C is enhanced by water, and at higher temperatures by oxygen.

Additional information

Authors: GRABKE H J, VDEh, Düsseldorf (DE);STEFFEN R, VDEh, Düsseldorf (DE);JESS A, c/o VDEh, Düsseldorf (DE);STEYLS D, CRM, Liège (BE)
Bibliographic Reference: EUR 20632 EN (2003), 132 pp. Euro: 25.00
Availability: EUR-OP reference: KI-NA-20632-EN-S Available from EUR-OP sales agents URL:
ISBN: ISBN: 92-894-5217-X
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