Mechanism of swelling of iron oxide pellets

Nakiboglu, Filiz (1981). Mechanism of swelling of iron oxide pellets PhD Thesis, School of Engineering, The University of Queensland. doi:10.14264/uql.2014.525

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Author Nakiboglu, Filiz
Thesis Title Mechanism of swelling of iron oxide pellets
School, Centre or Institute School of Engineering
Institution The University of Queensland
DOI 10.14264/uql.2014.525
Publication date 1981
Thesis type PhD Thesis
Supervisor Unknown
Total pages 198
Language eng
Subjects 03 Chemical Sciences
091207 Metals and Alloy Materials
Formatted abstract
The reduction behaviour of single crystals of wüstites containing Ca++, Li+, Na+, K+, Be++, Mg++, Sr++, Ba++, Al+3 and Si+4 has been examined in controlled CO-CO2 gas mixtures at 800°C, 960°C and 1200°C. The catastrophic swelling of wüstites on gaseous reduction coincides with the formation of an unusually open iron structure in which the iron appears as whiskers or needles as previously reported. However, the present investigations have also demonstrated that the whiskers do not necessarily constitute the only product form of the iron and under the certain conditions there is a transition from needle growth to porous growth of iron.

Metallographic examination has revealed that the exact shape of the reaction interface between wüstite and iron phases can vary considerably and is dependent on the rates of chemical reactions, rates of iron ion diffusion ( surface diffusion and bulk diffusion), the oxygen potential in the reducing gas and composition of wüstite. A number of previously unreported product morphologies have been observed which are shown to have significant effects on the macrostructural changes on reduction. A general theory of the decomposition of inorganic solids, consistent with the present observations, is proposed.
Additional Notes Other Title: Swelling of iron oxide pellets.

Document type: Thesis
Collection: UQ Theses (RHD) - UQ staff and students only
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Created: Wed, 26 Nov 2014, 11:01:50 EST by Mary-Anne Marrington on behalf of Scholarly Communication and Digitisation Service