Study of the Effect of a Plug with Torsion Channels on the Mixing Time in a Continuous Casting Ladle Water Model

Gerardo Aguilar,Fernando Saldaña,José Angel Ramos-Banderas,Alicia Aguilar-Corona,Gildardo Solorio-Diaz,Constantin A Hernández

doi:10.3390/met11121942

Abstract

The use of porous plugs in injecting gas through the bottom of a ladle forms vertical plumes in a very similar way to a truncated cone. The gas plume when exiting the plug has a smaller diameter compared to that formed in the upper zone of the ladle because inertial forces predominate over buoyancy forces in this zone. In addition, the magnitude of the plume velocity is concentrated in an upward direction, which increases the likelihood of low velocity zones forming near the bottom of the ladle, especially in lower corners. In this work, a plug with spiral-shaped channels with different torsion angles is proposed, with the objective that the gas, when passing through them, has a tangential velocity gain or that the velocity magnitude is distributed in the three axes and does not just focus on the upward direction, helping to decrease low velocity zones near the bottom of the ladle for better mixing times. For the experimentation, we worked in a continuous casting ladle water model with two configuration injections, which in previous works were reported as the most efficient in mixing the steel in this ladle. The results obtained using the PIV technique (particle image velocimetry) and conductimetry technique indicate that the plugs with the torsion channels at angles of 60° and 120° improve the mixing times for the two injection configurations.

Highlights

The ladle furnace is the main reactor of the secondary refining during the steelmaking process
For the case of 2 tuyeres at 0.66 R, the mixing time decreases by 11% when the modifier is used with a torsion angle of the channels of 60° and 8% with a torsion angle of 120°
For the case of 2 tuyeres at 0.66 R, the mixing time decreases by 11% when the modifier is used with a torsion angle of the channels of 60◦ and 8% with a torsion angle of 120◦

Summary

Introduction

The ladle furnace is the main reactor of the secondary refining during the steelmaking process. The final chemical composition of the steel is adjusted, and it is responsible for feeding it thermally homogeneous to the continuous casting process This reactor is in charge of decarburization, desulfurization and the removal of non-metallic inclusions [1,2]. Fangguan et al [36], in a water model, used three types of plugs with different slit geometries and diameters in order to investigate the effect of the diameter of the slit on the agitation of the steel; they found that as the diameter of the slit is increased, the time of mixing and the rate of elimination of inclusions diminish when the flow of gas is inferior to 5.26 NL·min−1, being that the plug is an important means to improve the efficiency of the agitation of the steel. We worked with two configuration injections, which in previous works were reported as the most efficient in mixing the steel in this ladle [3]

Experimental Configuration

Mixing Time 1

Obtaining the Velocity Fields with the PIV Technique

Selection of the Torsion Angle in the Flow Modifiers

Mixing Times

Conclusions