Effects of Slag Layer on the Multiphase Interaction in a Converter

Significance 

Among the established fundamental facts about the multiphase systems involved in oxygen steelmaking processes, one stands out. For instance, it is well known that a converter process can be described by the interaction between the liquid metal, molten slag, and gas. On the other hand, the general efficiency and feasibility of any steel refining process are affected by the fluid flow in the system.

Specifically, multiphase interaction has attracted significant attention of researchers who have identified it as a significant tool in optimizing oxygen furnace operations. Among the developed techniques used in converter multiphase modeling, computational fluid dynamics is widely preferred owing to its efficiency.

Despite remarkable steps in describing the gas-slag-metal interaction, the aforementioned methods do not describe the effects of the slag properties on the multiphase interactions. Therefore, researchers have been looking for alternative approaches for describing the multiphase interaction behavior which is a common phenomenon in industrial conditions.

To this note, The University of Science and Technology Beijing researchers: Dr. Lingling Cao, Dr. Qing Liu, Dr. Jiankun Sun, Professor Wenhui Lin and Professor Xiaoming Feng from the State Key Laboratory of Advanced Metallurgy investigated the behavior of multiphase interaction in a converter. Specifically, they utilized an 80-t converter based on the computational fluid dynamics modeling to determine the effects of slag layers on the gas-slag-metal interactions. Their research work is currently published in the research journal, JOM.

In brief, the authors commenced their experimental work by modeling an 80-t converter based on computer fluid dynamics. Next, they cross-examined the fluid flow in the converter using a multi-phase volume of fluid method. Consequently, they specifically investigated the effects of some of the parameters including the viscosity, slag thickness and surface tension on the dynamic interaction behavior of the converter. The study aimed at enhancing the efficiency and stability of steelmaking and refining processes.

The authors observed that the multiphase interactions resulted in the generation of cavities whose geometrical dimensions decreased with a corresponding increase in the slag thickness. However, the droplet generation and splashing that normally occurs in the converter could be easily prevented by a slag layer. This was attributed to the fact that the splashing behavior was not affected by the slag properties. Additionally, it was necessary to analyze the momentum of the multiphase interaction. It was noted that the slag parameters such as viscosity and surface tension had got negligible effects on the momentum and especially in regions far from the interaction zones.

In summary, University of Science and Technology Beijing scientists successfully demonstrated the different effects of the slag layer and properties on the multiphase interaction behavior in a converter. To actualize their study, they examined oxygen jet impingement onto the interface of the slag and metal based on both computational fluid dynamics and multiphase volume of fluid simulation method. In general, the study presents vital information that will enhance process optimization, stability, and efficiency of oxygen furnace-based operations.

About the author

Professor Qing Liu received the PhD, M.S. and B.S. degrees in metallurgical engineering from the University of Science and Technology of Beijing (USTB), in 2002, 1995 and 1989 respectively. He is now a Professor with the State Key Laboratory of Advanced Metallurgy in USTB. His main research interests include simulation and optimization of metallurgical process, metallurgical process engineering, optimization and quality control in the steelmaking-continuous casting process.

Professor Liu is a topic editor of Frontier in Materials and an editorial member of Continuous Casting (Chinese edition), China Metallurgy, and Material ScienceInternational Chinese Journal. He has received several awards from Chinese scientific societies or education institutes, such as the 10th China Invention Award-Human Figure Award in 2018, the Higher Education Scientific and Technological Progress Award (China) in 2015, Metallurgy Science and Technology Award (China) in 2014,etc.

Reference

Cao, L., Liu, Q., Sun, J., Lin, W., & Feng, X. (2019). Effect of Slag Layer on the Multiphase Interaction in a Converter. JOM, 71(2), 754-763.

Go To JOM

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