The characterization of electric arc furnace (EAF) dust shows that bubble burst at the liquid steel surface is the principal source of dust emission. We have therefore developed an experimental device for studying this phenomenon. As in the case of the air-water system, the bubble-burst gives birth to two types of droplets: film drops and jet drops. The jet drop formation is observed with high-speed video. The film drop aerosol is collected on filters and, then, characterized by means of SEM, granulometric and gravimetric analyses. Results are presented and discussed. The quantification of both types of projections leads to the conclusion that the film drop projections represent the major source of dust. The amount of film drops greatly decreases with the parent bubble size. Under 4.5 mm in bubble diameter, no film drops are formed. Decreasing enough the bubble size would therefore represent an effective solution for reducing drastically the EAF dust emission. Published in Powder Technology, 2005, 157, 1-3, 2-11.

We have developed an experimental device for studying the main mechanism of dust formation in electric arc furnace steelmaking: the burst of gas bubbles at the liquid steel surface. As in the case of the air-water system, the bubble-burst process takes place in three steps: breaking of the film cap, projection of film drops, and projection of jet drops. The film break and the jet drop formation are observed with a high-speed video camera. The film drop aerosol enters a particle counter, which characterizes the drops in size and number. Results are presented and discussed. The quantification of both types of projections leads to the conclusion that the film drop projections represent the major source of dust. The amount of film drops greatly decreases with the parent bubble size. Bubbles with diameter under 4 mm theoretically do not produce film drops. Decreasing the CO-bubble size enough would therefore represent an effective solution for reducing drastically the electric arc furnace dust emission.

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