Dust formation by bubble-burst phenomenon at the surface of a liquid steel bath

TL;DR

This study investigates how bubble bursting at the surface of liquid steel causes dust formation, identifying film drops as the main source and suggesting bubble size reduction as a dust mitigation strategy.

Contribution

The paper introduces an experimental setup to analyze bubble burst mechanisms in steelmaking and quantifies the impact of bubble size on dust production, highlighting a potential dust reduction method.

Findings

Film drops are the main source of dust during bubble burst.

Bubbles smaller than 4mm produce significantly fewer film drops.

Reducing bubble size could drastically decrease dust emissions.

Abstract

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 4mm 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.