Slag foaming phenomena and its suppression techniques in BOF steelmaking process

Some basic studies using the X-ray fluoroscopy technique were carried out to understand slag foaming phenomena in BOF process. The BOF slag in contact with hot metal showed a generation of very fine size CO bubbles at the slag-metal interface, and formed a stable foam. The lump iron ore added into BOF slag decomposed faster, but showed less foaming than sinter ore did. The anti-foaming agent and coke were added into foamed BOF slag to compare their effectiveness of foam suppression. At the same time, various attempts were made to control the excessive slag foaming during BOF operation. Practice modifications such as oxygen blowing pattern and ore addition, and the installation of the slopping control button were effective and significantly reduced slopping. The slopping detection system involving oxygen lance vibration measurements were on-line installed for prompt and accurate control of slag foaming in BOF converter.