Year

2018

Degree Name

Doctor of Philosophy

Department

School of Mechanical, Materials, Mechatronic and Biomedical Engineering

Abstract

Steelmakers are becoming more motivated to use iron ore resources with a wider range of grades and mineral types that were previously considered unsuitable or uneconomical for sintering. In this respect, specific issues which now require further investigation and understanding include the sintering of ores with a) overall higher gangue content, b) elements that cause problems in the steel manufacturing operations, and/or c) distinctive sintering performance compared with traditional hematite-rich iron ores. Laboratory-based investigation of the sintering performance and the behaviour of gangue impurities during sintering is an important step towards the successful utilisation of these resources in steelmaking.

To explore the feasibility of small-scale sintering pot testing, a ‘millipot’ facility (diameter of 53 mm and height of 400 mm) was established and used to examine the sintering performance of iron ores and other non-traditional ferrous materials. The sintering performance of a millipot was examined across a range of operational conditions (coke rate and suction pressure) and compared with an industrial sinter strand operation. Tablet tests were also performed to assist in the design of the millipot experiments and identify conditions for achieving mineral composition similar to the industrial sinter. For the millipot experiments, the materials used need to be compacted to increase the bulk density, and a higher coke rate is required to compensate the high heat loss caused by wall effects. A higher suction pressure is also necessary to maintain an oxidising atmosphere in the sinter bed. As expected, it was not possible to completely eliminate the wall effect, which results in more primary hematite at edges of the sintered column. Heavier compacting at the periphery of the column can minimise the wall effect. The sintered material from the centre of column simulates industrial sinter reasonably well. As such, millipot provides a practical technique to evaluate the sintering process and material performance at laboratory scale, helping to bridge the gap between tablet sintering and large scale pot sintering, or full scale plant trials. The results of millipot testing can be used for designing larger scale experiments or commercial sintering trials...

This thesis is unavailable until Thursday, September 05, 2019

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