Physical modelling of the effect of slag and top-blowing on mixing in the AOD process

Tim Haas, Ville Valtteri Visuri, Aki Kärnä, Erik Isohookana, Petri Sulasalmi, Rauf Hürman Eriç, Herbert Pfeifer, Timo Fabritius

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

6 Citations (Scopus)

Abstract

The argon-oxygen decarburization (AOD) process is the most common process for refining stainless steel. High blowing rates and the resulting efficient mixing of the steel bath are characteristic of the AOD process. In this work, a 1:9-scale physical model was used to study mixing in a 150 t AOD vessel. Water, air and rapeseed oil were used to represent steel, argon and slag, respectively, while the dynamic similarity with the actual converter was maintained using the modified Froude number and the momentum number. Employing sulfuric acid as a tracer, the mixing times were determined on the basis of pH measurements according to the 97.5% criterion. The gas blowing rate and slag-steel volume ratio were varied in order to study their effect on the mixing time. The effect of top-blowing was also investigated. The results suggest that mixing time decreases as the modified Froude number of the tuyeres increases and that the presence of a slag layer increases the mixing time. Furthermore, top-blowing was found to increase the mixing time both with and without the slag layer.

Original languageEnglish
Title of host publicationAdvances in Molten Slags, Fluxes, and Salts
Subtitle of host publicationProceedings of the 10th International Conference on Molten Slags, Fluxes and Salts 2016
PublisherSpringer International Publishing AG
Pages999-1008
Number of pages10
ISBN (Print)9783319486253
Publication statusPublished - 2016
MoE publication typeA4 Article in a conference publication
EventInternational Conference on Molten Slags, Fluxes and Salts - Seattle Grand Hyatt, Seattle, United States
Duration: 22 May 201625 May 2016
Conference number: 10

Conference

ConferenceInternational Conference on Molten Slags, Fluxes and Salts
Abbreviated titleMOLTEN
CountryUnited States
CitySeattle
Period22/05/201625/05/2016

Keywords

  • AOD
  • Mixing time
  • Slag
  • Top-blowing

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