Behavior of Gas–Slag–Metal Emulsion with Nozzle‐Twisted Lance in Converter Steelmaking Process

Abstract

Oxygen lance is the key to realize the emulsification of gas–slag–metal in the converter steelmaking process, which determines successful completion of metallurgical tasks. Herein, a 3D full‐size gas–slag–metal coupling model of the nozzle‐twisted lance in a 120t converter is established. The behavioral characteristics of gas–slag–metal of nozzle‐twisted lances (swirl angle 0°/5°/10°/15°) are studied. With the increase in the swirl angle, the axial velocity is reduced; the radial and tangential velocities are increased, and the coverage area of the slag layer, the splashing amount, and its height are reduced. In the longitudinal section, when the swirl angle increases from 0° to 15°, the areas of high‐velocity and dead zones are reduced by 15% and 36%, respectively, and the area of low‐velocity zone is increased by 17%. At different depths of molten bath, with the increase in the swirl angle, the area of high‐velocity zone first increases and then decreases; the area of low‐velocity zone increases, and the area of dead zone decreases. Finally, the industrial experiment with the nozzle‐twisted lance is carried out in a 120t converter. The phosphorus content, the carbon–oxygen product, and the total iron content in slag are all reduced.

Effect of cavity shape caused by jet impact of swirl-type oxygen lance on molten bath mixing efficiency

“…Higuchi and Tago 19 used physical experiments to study the jet behaviour and splashing of swirl-type oxygen lance, and it was found that a swirl angle of 11.4° was most effective for reducing the splashing rate. Lv et al 20,21 used physical experiments and numerical simulations to analyse the influence that the swirl angle has on the emulsification of gas–slag–metal phases and the stirring efficiency. Liu et al 22 used numerical simulation to discuss the stirring efficiency that swirl-type oxygen lance has on the molten bath, and it was determined that a swirl angle of 8° was optimal for a 120 t dephosphorisation converter.…”

Effect of Bottom Tuyere Arrangement Based on Impact Cavity Morphology on Kinetic Behavior of Molten Bath in Converter

“…Due to the limitations of detection technologies and harsh environments, it is difficult to intuitively observe and analyze the flow-related phenomena in steelmaking converter under industrial situations. In recent decades, numerous researchers have used physical and numerical simulations to investigate the phenomena such as gas-slag-metal interaction, [3][4][5][6][7][8][9] splashing droplets, [10][11][12][13][14][15][16][17][18][19][20][21] impact cavity, [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] flow and mixing of the molten bath. Odenthal et al [3] proposed a comprehensive mathematical model to reasonably predict flow phenomena such as supersonic jet penetration and phase interface motion.…”

“…Dong et al [ 8 ] found that the single‐flow post‐combustion lance can strengthen the gas–slag–metal interaction and reduce the slag coverage area. Lv et al [ 9 ] recognized that as the swirl angle of nozzle‐twisted lance increases from 0° to 15°, the slag coverage area and splashing droplets decrease.…”

Effect of Lance Design on Jet Characteristics in 250 t Converter

“…While early studies focused on single-hole jet behaviors, [7][8][9][10][11][12] oxygen lance with multiple nozzles supersonic jets was widely used in field production because of their ability to meet blast furnace scale-up and high refining efficiency. [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27] Smith [13] analyzed the results of plant experience with two-hole and single-hole oxygen lances. It was concluded that when the main hole inclination angles were greater than or equal to 10 , the flow field was entirely separated.…”

“…Thus, deviation degree of the jet velocity center line increased, and the impact area of the jet to the bath decreased. Lv et al [18,19] developed a 3D full-scale gas-slag-metal coupling model for a 120 t converter nozzle-twist lance to investigate different swirl angles. With the increase in the swirl angle, the axial velocity is reduced.…”