Optimized Scheme for Accelerating the Slagging Reaction and Slag–Metal–Gas Emulsification in a Basic Oxygen Furnace

Abstract

Basic oxygen furnace (BOF) steelmaking is widely used in the metallurgy field. The slagging reaction is a necessary process that oxidizes C, Mn, Si, P, S, and other impurities and therefore directly affects the quality of the resultant steel. Relevant research has suggested that intensifying the stirring effect can accelerate the slagging reaction and that the dynamic characteristics of the top blow are the key factor in exploring the related complex physical and chemical phenomena. To address the issue, the standard k-ω turbulence model and level-set method were adopted in the present work and a fluid dynamics model was developed for a BOF. Accordingly, the slag–metal–gas emulsion interaction and stirring effect were investigated, and the interference mechanism of a multi-nozzle supersonic coherent jet was revealed. Finally, a self-adjustment method based on fuzzy control is proposed for the oxygen lance. The results indicate that the transfer efficiency of jet kinetic energy at the gas–liquid interface is the critical factor for the slagging reaction and that multi-nozzle oxygen lances with a certain twisted angle have important advantages with respect to stirring effects and splashing inhibition. The fuzzy control method predicts that the optimal nozzle twist angle is within the range of 7.2° to 7.8°. The results presented herein can provide theoretical support and beneficial reference information for BOF steelmaking.

Keywords

• basic oxygen furnace
• slagging reaction
• slag-metal-gas emulsions
• multi-nozzle oxygen lance
• supersonic coherent jet
• fuzzy control method