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Control of ejections caused by bubble bursting in secondary steelmaking processes

Funded under: FP5-GROWTH


The formation of melt ejections caused by gases exiting from steel melts in secondary metallurgy was investigated.

HUT (Helsinki) observed the passage of single gas bubbles through liquid steel and slag melts by using a special transmission X-ray technique. Also, water model investigations were carried out. The direct observations, accompanying analyses from samples and theoretical descriptions of the phenomena have given a quantitative description of droplet formation and ejections of liquid slag and steel from single bursting bubbles.

LTH {RWTH, Aachen) investigated the correlations between droplet formation {quantities and size distributions) and process parameters {gas injection rates, viscosities, surface tensions) with a water model and subsequently with 150kg melts in an electric furnace equipped with a bottom gas injection device.

TKS (steelworks, Oortmund) carried out investigations concerning droplet formation and splashing in the OH degasser and in the HALT (CAS-OB) facility. Trials included the visual in-line observation of bubble bursting and splashing by means of an optical furnace probe and a thorough analysis of accretions.

Summarising the results, it became evident that the ejections formed can be classified into three categories:

-Film droplets " 0.1 mm).
-Jet droplets (0.1 to 2 mm).
-Splashes (> 2 mm).

Film droplets result from bursting of the bubble film, while jet droplets are formed when the bubble cavity collapses after the film bursts. Splashes result from interaction of a gas stream with the liquid when exiting at a relatively high speed. y high speed.

Additional information

Authors: No authors provided, Helsinki University of Technology, Espoo (FI);No authors provided, Rheinisch-Westfalische Technische Hochschule, Aachen (DE);No authors provided, Thyssen Krupp Stahl AG, Duisburg (DE)
Bibliographic Reference: EUR 19487 EN (2001), pp.135. Euro: 20.50
Availability: Available by EUR-OP sales agent
ISBN: ISBN: 92-894-1230-5
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