Effect of varied oxygen levels on the oxidation of a magnetite pellet bed during pot furnace indurationShow others and affiliations
2021 (English)In: ISIJ International, ISSN 0915-1559, E-ISSN 1347-5460, Vol. 61, no 5, p. 1439-1449Article in journal (Refereed) Published
Abstract [en]
An excess amount of oxygen originating from hydrogen production is likely to be available as part of the HYBRIT (Hydrogen Breakthrough Ironmaking Technology) initiative, aimed at producing fossil-free steel by replacing coking coal with hydrogen. Oxygen enrichment during magnetite pellet induration can lead to reduced fuel amounts and increased productivity. Induration of magnetite iron ore pellets liberates considerable amounts of heat when magnetite is oxidised to hematite. Elevated oxygen levels in the process gas are expected to promote the oxidation reaction, resulting in increased process efficiency. However, more information is required to enable the transition towards a higher oxygen level process and improved production rate, while maintaining the metallurgical properties of the pellet bed. In this study, interrupted pot furnace experiments were conducted on a magnetite pellet bed (approximately 100 kg) at Luossavaara-Kiirunavaara Aktiebolag to investigate the effect of oxygen levels at approximately 6%, 13%, and 30% O2. Temperature profiles are measured and pellet properties (compression strength, porosity, oxidation degree, microstructures) are analysed at different bed heights. The higher oxygen level (approximately 30% O2) intensifies the oxidation reaction, resulting in increased temperature, oxidation rate and compression strength across the vertical bed height. Three different pellet oxidation profiles are identified, namely, homogenous oxidation across the pellet, complete oxidation of the pellet shell and an unreacted core with a sharp/distinct interface, and partial oxidation of the pellet shell and an unreacted core. A higher oxygen level results in an increased oxidation rate, while the temperature controls the pellet oxidation profile. © 2021 Iron and Steel Institute of Japan. All rights reserved.
Place, publisher, year, edition, pages
Iron and Steel Institute of Japan , 2021. Vol. 61, no 5, p. 1439-1449
Keywords [en]
Coal industry, Coking, Compressive strength, Hematite, Hydrogen production, Iron ore pellets, Iron ores, Magnetite, Oxygen, Pelletizing, Temperature control, Compression strength, Increased productivity, Increased temperature, Ironmaking technology, Metallurgical properties, Oxidation reactions, Process efficiency, Temperature profiles, Oxidation
National Category
Metallurgy and Metallic Materials
Research subject
Process Metallurgy
Identifiers
URN: urn:nbn:se:ltu:diva-85021DOI: 10.2355/ISIJINTERNATIONAL.ISIJINT-2020-469ISI: 000661550700013Scopus ID: 2-s2.0-85106668117OAI: oai:DiVA.org:ltu-85021DiVA, id: diva2:1564056
Note
Validerad;2021;Nivå 2;2021-06-11 (johcin)
2021-06-112021-06-112021-12-13Bibliographically approved