Study on CO2 bubble growth and detachment in liquid steel induced by thermal decomposition reaction with physical modeling

Abstract

The bubbles have been widely applied in industrial processing, including steelmaking. Recently, industrial trials of natively generated bubbles via decomposition reactions have been successfully adopted in steel refining and inclusion removal. The refining efficiency was proved to be outstanding due to the small bubble sizes and the subsequent satisfying dynamic conditions. However, the bubble behaviors, including growth and detachment, are still not thoroughly clarified due to the strict requirements for observation conditions. Therefore, the growth and detachment behavior of the bubbles generated by decomposition reactions were carefully observed with physical modeling and shadow imaging method. The detachment sizes of the bubbles were extracted accordingly. Based on the statistical data on the detachment bubble sizes, a traditional nozzle flow model was modified for the prediction of the bubble detachment size in decomposition reactions. This work provides the foundation for further studies on the interaction mechanism between the natively generated bubbles and the impurities in liquid steel in terms of inclusion removal.

Keywords

• Bubble detachment
• Shadow imaging method
• Decomposition reaction
• CO2