Marienhütte GmbH, Graz:

H.-J. Krassnig, Dr. Eng., krassnig@marienhuette.at

H. Sommerauer, Eng.

H. Fohringer, Eng., Managing Director

vatron GmbH, Linz, Austria:

Ch. Koubek, Eng.

R. Krump., Eng.

In the electric steel production a foaming slag is very important to achieve a high productivity as well as low wear. Formation mechanism of carbon monoxide for slag foaming is explained. Share of different CO₂ sources in the electric steelmaking at Stahl- und Walzwerk Marienhütte GmbH is presented (it includes coal, natural gas, scrap, electrodes and other elements) as well as position of CCD camera in front of the electric arc furnace slag door. Visualization of the Optical Foaming Slag Manager and its control cycle including 5 phases is described. Slag indexes and carbon feeding rates for a "good" and "bad" foamed slag are comparatively shown. Measured slag index versus calculated slag index are displayed and average carbon consumption during 2010 and 2011 are displayed. To achieve a high degree of efficiency, the use of a fully automated system of fine coal injection control is inevitablebased on a precise detection of the slag level. Hence, in collaboration with vatron GmbH, Marienhütte developed ahighly reliable and efficient method to control the fine carbon supply based on the optical detection of the slag level.

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