1. Quantitative analysis of iron ore processing J.M. Cadogan Department of Physics and Astronomy University of Manitoba Winnipeg, Manitoba, R3T 2N2 Canada E-mail: cadogan@physics.umanitoba.ca

2. There are a number of promising emerging technologies in the World’s steel production industry. Their advantages over traditional blast-furnace production are: Lower overall investment and production costs The avoidance of certain processing steps Iron ore ‘fines’ can be used Reducing environmental impact One such alternative is Direct Reduction whereby iron ore is reduced to metallic iron below the melting temperatures of the constituent materials. (DR was actually known in ancient times !) We have studied the Direct Reduction of Australian iron ore by heating the ore in hydrogen at either 600 o C or 800 o C. 57 Fe Mössbauer Spectroscopy allows one to follow the evolution of the Fe- bearing phases as a function of such parameters as reduction time. Direct Reduction

3. Starting material (mainly Haematite Fe 2 O 3 with traces of non-magnetic Wüstite Fe ~0.95 O) Finished product (mainly  -Fe with a trace of Magnetite Fe 3 O 4 ) All 57 Fe Mössbauer spectra shown here were obtained at RT

4. Transformation of iron ore to iron at 600 o C: Processing time 57 Fe Mössbauer spectroscopy allows us to follow the kinetics of the transformation from iron ore (Haematite [Fe 2 O 3 ], Magnetite [Fe 3 O 4 ] and non-magnetic Wüstite ([Fe ~0.95 O]) to iron (α-Fe).

5. Mössbauer spectroscopy is ideally suited to monitoring the transformation of iron ore to iron Quantitative analysis of the various Fe-bearing phases present can be obtained, although assumptions with regard to parameters such as the f-factors of the various phases involved may be needed. Reduction of Fe 2 O 3 is quite rapid compared to that of Fe 3 O 4 and FeO (Fe 2 O 3 has virtually disappeared from the iron ore sample reduced in hydrogen at 800 o C for 30 seconds !) The extrapolation of the  -Fe content to zero wt% does not pass through the origin (t = 0). This may reflect an activation time for the full transformation of Fe 2 O 3 into Fe 3 O 4 and FeO, prior to the gradual final transformation to  -Fe. References A. Zhou, M.Sc. Thesis, University of NSW, Sydney, Australia (1998) V. Sahajwalla, J.M. Cadogan and A. Zhou, AusIMM Annual Conf. (1996) pp 267-272 A. Zhou, K. Suzuki, V. Sahajwalla and J.M. Cadogan, Scand. J. Metallurgy 28, 65-9 (1999)