University of Oulu

Kemppainen, A., Iljana, M., Heikkinen, E., Paananen, T., Mattila, O., Fabritius, T. (2014) Reduction Behavior of Cold-bonded Briquettes under Simulated Blast Furnace Conditions. ISIJ International, 54 (7), 1539-1545.

Reduction behavior of cold-bonded briquettes under simulated blast furnace conditions

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Author: Kemppainen, Antti1; Iljana, Mikko1; Heikkinen, Eetu-Pekka1;
Organizations: 1Laboratory of Process Metallurgy, University of Oulu, P.O Box 4300 FI-90014, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 0.9 MB)
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Language: English
Published: Iron and Steel Institute of Japan, 2014
Publish Date: 2021-01-20


Recycling of fine sized iron-rich by-products back to blast furnace (BF) process in the form of cement-bonded briquettes has become a common procedure in steel plants. Replacing part of the cement by Ground Granulated Blast Furnace Slag (GGBFS) is also a common method to reduce cement consumption. When the briquettes are subjected to high temperature and reducing atmosphere in the BF, the cement phases decompose and the iron oxides undergo a series of phase transformations. To avoid early disintegration and to improve the performance of the briquettes, it is necessary to study these reactions during the reduction. In the present study the reduction behavior of the BF briquette samples was studied by experimental methods in a laboratory scale furnace, which simulates the conditions of the BF shaft in a CO–CO₂–N₂ atmosphere. With interrupted experiments the composition of the briquette was studied in different reduction stages of the BF shaft. The effect of GGBFS as a binder material on the reduction was studied with GGBFS containing briquette samples. The reduction of briquettes was compared to an olivine pellet which was used as a reference sample. Considerably higher reduction rate was detected with the briquettes compared to the pellet at 1100°C when reduced to metallic iron. 25–50 vol-% swelling in the briquette samples was detected during the wüstite-iron reduction step at 900–1000°C. X-ray diffraction (XRD) was used to observe the phase transformations in the Fe–Fe₂O₃–CaO system of the briquette and the results are in agreement with the theory.

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Series: ISIJ international
ISSN: 0915-1559
ISSN-E: 1347-5460
ISSN-L: 0915-1559
Volume: 54
Issue: 7
Pages: 1539 - 1545
DOI: 10.2355/isijinternational.54.1539
Type of Publication: A1 Journal article – refereed
Field of Science: 216 Materials engineering
Funding: This research is a part of the Energy Efficiency & Lifecycle Efficient Metal Processes (ELEMET) research program coordinated by the Finnish Metals and Engineering Competence Cluster (FIMECC). Ruukki Metals Oy and the Finnish Funding Agency for Technology and Innovation (TEKES) are acknowledged for funding this work.
Copyright information: © 2014 by The Iron and Steel Institute of Japan.