University of Oulu

Matti Aula, Thorsten Demus, Thomas Echterhof, Marko Huttula, Herbert Pfeifer, Timo Fabritius, On-line Analysis of Cr2O3 Content of the Slag in Pilot Scale EAF by Measuring Optical Emission Spectrum of Electric Arc, ISIJ International, Released March 23, 2017, Online ISSN 1347-5460, Print ISSN 0915-1559,,

On-line analysis of Cr₂O₃ content of the slag in pilot scale EAF by measuring optical emission spectrum of electric arc

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Author: Aula, Matti1; Demus, Thorsten2; Echterhof, Thomas2;
Organizations: 1Process Metallurgy Research Group, University of Oulu, P.O. Box 4300, FI-90014 Finland
2RWTH Aachen University, Department of Industrial Furnaces and Heat Engineering, Kopernikusstrasse 10. 52074 Aachen, Germany
3Electron Spectroscopy Group, University of Oulu, P.O. Box 3000, FI-90014 Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 0.5 MB)
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Language: English
Published: Iron and Steel Institute of Japan, 2017
Publish Date: 2018-04-05


Control of slag Cr₂O₃ content is essential in stainless steelmaking electric arc furnace (EAF). Excessive Cr₂O₃ content of slag lead to high Cr₂O₃ content after the EAF tapping, since the solid precipitates forming in high Cr₂O₃ contents are not reduced significantly during the tapping procedure. In this work the slag Cr₂O3 content during the EAF process was analysed by measuring the optical emission spectrum of the electric arc. The measurements were conducted in a pilot EAF situated in Aachen, Germany. Cr₂O₃ content of the slag was increased with periodical additions of Cr₂O₃ powder. The line ratios calculated from the optical emission spectra were compared to the results of the X-ray fluorescence (XRF) analysis of the slag samples taken from the furnace. The results indicate that best accuracy in a pilot scale can be obtained by using Ca I, Fe I or Mn I lines as reference for Cr I lines. By combining the most accurate line ratios of these three components, the Cr₂O₃ composition of the slag could be measured with an average absolute error of 0.62%-points and a standard deviation of 0.49%-points. The results suggest that Fe I and Mn I lines are the most promising reference lines for analysing Cr₂O₃ content of industrial EAF slag.

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Series: ISIJ international
ISSN: 0915-1559
ISSN-E: 1347-5460
ISSN-L: 0915-1559
Volume: 57
Issue: 3
Pages: 478 - 486
DOI: 10.2355/isijinternational.ISIJINT-2015-677
Type of Publication: A1 Journal article – refereed
Field of Science: 216 Materials engineering
114 Physical sciences
116 Chemical sciences
Funding: The Finnish Funding agency for Technology and innovation (TEKES) and Technology Industries of Finland Centennial Foundation Fund for the Association of Finnish Steel and Metal Producers are acknowledged for funding of this work.
Copyright information: © 2017 ISIJ. Published in this repository with the kind permission of the publisher.