Title

YIELD IMPROVEMENT THROUGH ENHANCED LADLE BOTTOM DESIGN (ELBY)

YIELD IMPROVEMENT THROUGH ENHANCED LADLE BOTTOM DESIGN (ELBY)

Authorship

Heaslip, L.J.; Dorricott, J.D.; Richaud, J.; Rogler, J.P.; Alves, W.A.

Heaslip, L.J.

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Dorricott, J.D.

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Richaud, J.

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Rogler, J.P.

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Alves, W.A.

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DOI

10.5151/2594-5300-2004-14177-0055

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Abstract

When slag is detected leaving a ladle, a significant residual quantity of steel often remains behind when flow is stopped, and this results in a costly loss of yield. In order to minimize the average quantity of steel residual in the ladle, ladle bottom geometry should be optimized. To improve ladle yield, an understanding of the fluid flow phenomena (including vortexing and surface collapse) occurring during the final stages of draining is necessary. Both computational fluid dynamics (CFD) and physical (water) modeling have been used to gain this understanding. The influence of steel flow rate on the bath depth of vortexing and surface collapse was studied. It was found that as ladle draining proceeds, three phenomena typically occur: (1) early vortexing (low strength intermittent vortices), (2) full vortexing (a slag-entraining funnel), and (3) surface collapse (pressure in slag exceeds pressure in the steel and the slag flow overwhelms steel flow). With the aid of CFD, optimized ladle bottom geometries (ELBY) that reduce residual steel at the onset of slag flow have been generated. CFD modeling has been found to correspond well with physical modeling and it was concluded that CFD analysis can be used to predict ladle draining phenomena. Plant testing of an ELBY ladle bottom design has shown that significant yield savings can be achieved.

When slag is detected leaving a ladle, a significant residual quantity of steel often remains behind when flow is stopped, and this results in a costly loss of yield. In order to minimize the average quantity of steel residual in the ladle, ladle bottom geometry should be optimized. To improve ladle yield, an understanding of the fluid flow phenomena (including vortexing and surface collapse) occurring during the final stages of draining is necessary. Both computational fluid dynamics (CFD) and physical (water) modeling have been used to gain this understanding. The influence of steel flow rate on the bath depth of vortexing and surface collapse was studied. It was found that as ladle draining proceeds, three phenomena typically occur: (1) early vortexing (low strength intermittent vortices), (2) full vortexing (a slag-entraining funnel), and (3) surface collapse (pressure in slag exceeds pressure in the steel and the slag flow overwhelms steel flow). With the aid of CFD, optimized ladle bottom geometries (ELBY) that reduce residual steel at the onset of slag flow have been generated. CFD modeling has been found to correspond well with physical modeling and it was concluded that CFD analysis can be used to predict ladle draining phenomena. Plant testing of an ELBY ladle bottom design has shown that significant yield savings can be achieved.

Keywords

Ladle yield; Ladle draining; Draining vortex; Ladle vortex; Slag entrainment.

Ladle yield; Ladle draining; Draining vortex; Ladle vortex; Slag entrainment.