Improvement of inclusion flotation during RH treatment
This project involving Arcelor Research, CSM, BFI and RWTH was aimed at improving the inclusion removal during RH treatments. Activities were managed in accordance with the project planning. The metal throughput in the RH legs is known to increase with the lift argon flow rate injected in the up-leg. We have shown some benefits of having enough tuyères for the gas injection in the up-leg. Moreover, the RH is a gas pump, whose functioning is down-graded if the lift gas flow rate exceeds a limit. The simple model supposes an exponential time-decrease of the inclusion content. This model is based upon a characteristic constant k. We confirmed the applicability of such a model during in-plant experimentations. Direct numerical simulation, without aggregation, gave the same trend. The aggregation of inclusions was introduced so as to describe in more details what happens and it gave a good agreement with measurements. A key factor is the compactness of fractal dimension of cluster. The recommendations are as follows: use killed liquid ladle slag; maximise the metal throughput in the RH, if necessary increase the number of tuyères and the lift gas flow rate but without exceeding a critical value; begin the treatment with more than 300 ppm of oxygen to maximise the aggregation of inclusions; apply a five-minute minimum metal circulation, for some configuration up to 10 minutes; decrease the argon flow rate for another three to five minutes circulation in order to maximise the floatation of inclusions.
Bibliographic Reference: EUR 22388 EN (2006), 116 pp. Euro: 25
Availability: Katalogue Number: KI-NA-22388-EN-S The paper version can be ordered online and the PDF version downloaded at: http://bookshop.europa.eu
ISBN: ISBN: 92-79-03054-X
Record Number: 200719298 / Last updated on: 2007-07-10
Original language: en
Available languages: en