University of Oulu

Iljana, M., Kemppainen, A., Paananen, T., Mattila, O., Heikkinen, E., Fabritius, T. (2016) Evaluating the Reduction-Softening Behaviour of Blast Furnace Burden with an Advanced Test. ISIJ Internationa, 56 (10), 1705-1714.

Evaluating the reduction-softening behaviour of blast furnace burden with an advanced test

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Author: Iljana, Mikko1; Kemppainen, Antti1; Paananen, Timo2;
Organizations: 1Process Metallurgy Research Unit, University of Oulu, PO Box 4300, FI-90014 University of Oulu, Finland
2SSAB Europe Oy, Rautaruukintie 155, FI-92100 Raahe, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 3 MB)
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Language: English
Published: Iron and Steel Institute of Japan, 2016
Publish Date: 2021-01-25


A ferrous burden loses its permeability in the cohesive zone of a Blast Furnace (BF), where the iron burden materials soften and melt. A tailor-made, high-temperature furnace named ARUL (Advanced Reduction under Load) was used here to study the reduction-softening behaviour of acid and olivine pellets and basic sinter under simulated BF gas, temperature and pressure conditions. The ARUL test showed the best reduction-softening properties for the basic sinter. The sinter sample resisted up to 1329°C and achieved a reduction degree of 90.2% until a gas-impermeable structure was formed in a packed bed, whereas the acid pellet lost its permeability at 1160°C and only reduced to a reduction degree of 48.7%. The olivine pellet had intermediate reduction-softening properties with a final temperature of 1252°C and a final reduction degree of 68.7%. The differences between the test materials were assessed as being caused mainly by different chemistry, but it was also revealed that the sinter sample remained its macro-porosity markedly better in relation to the pellets, providing routes for reducing gases.

The experimental results were compared to the phase diagrams calculated with the computational thermodynamic software FactSage. Phase diagrams for the 5-component FeO–SiO₂–CaO–MgO–Al2O₃ systems with constant CaO, MgO and Al₂O₃ contents were used to estimate the formation of liquid phases in the test materials. The computed phase diagrams gave an estimate of the liquid formation; however, some limitations were also found in the utilization of the computations because of the need to define the system in certain simplicity.

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Series: ISIJ international
ISSN: 0915-1559
ISSN-E: 1347-5460
ISSN-L: 0915-1559
Volume: 56
Issue: 10
Pages: 1705 - 1714
DOI: 10.2355/isijinternational.ISIJINT-2016-117
Type of Publication: A1 Journal article – refereed
Field of Science: 216 Materials engineering
Funding: SSAB Europe, the Finnish Funding Agency for Technology and Innovation (TEKES) and the Association of Finnish Steel and Metal Producers are acknowledged for funding this work.
Copyright information: © 2016 by The Iron and Steel Institute of Japan.