Modeling of Bubble Transportation, Expansion, as Well as Adhesion of Inclusions in a Ladle With Different Tuyeres

Abstract

A new model is developed to describe the coalescence and breakup between bubbles and inclusions. In this model, the density of bubble attached inclusions is calculated through mass conservation equation. The momentum exchange after breakup or coalescence is derived through momentum conservation equation, which are tracked by discrete particle method (DPM). Three continuous phases (air-slag-steel) are considered in a ladle, and the unsteady turbulent flow is computed through k-e method. What's more, bubble expansion due to decreasing of hydraulic pressure is also taken into account. Results show that due to the bubble expansion, bubble density is mostly decreased to 0.3 to 0.8 kg/m 3 . However, after attaching some inclusions, the bubble density significantly rises to 20 to 60 kg/m 3 . The optimal bubble diameters attaching inclusions are ranged between 1.5 and 10 mm. For traditional slot-slot matched tuyeres (S-S mode), the inclusion removement ratio is 29.48 pct; By comparison, after employing the slot-porous matched tuyeres (S-P mode), the inclusion removements ratio rises to 36.34 pct. The mixing time is also shortened after adopting the S-P mode. The reason for this phenomenon is because the slot tuyere produces a strong asymmetry stream that drives more liquid to flow at the bottom of the ladle. And at the same time, the porous tuyere produces more fine bubbles to entrap more inclusions to the top. Taking advantages of porous and slot tuyeres, the mixing behavior and inclusion removements improves a lot. The result is beneficial for improving ladle refining.

Physical Model of Inclusions Removal at Static Steel–Slag Interface

“…Inclusion removal is a crucial step in the steelmaking process, and the removal effect directly affects steel quality [1][2][3][4]. At present, the main methods of inclusion removal include gas stirring in ladles [5][6][7][8][9][10], Ruhrstahl-Heraeus treatment [11][12][13][14], slag washing [15][16][17], bubble flotation [18], removal in tundishes [19][20][21][22], and continuous casting mold [23][24][25][26], among others. These methods promote inclusions to float to the slag-steel interface so that the inclusions are more easily removed by refining slag absorption.…”

Effect of Salt Solution Tracer Dosage on the Transport and Mixing of Tracer in a Water Model of Asymmetrical Gas-Stirred Ladle with a Moderate Gas Flowrate

“…Presently, argon stirring ladles are widely employed in secondary refining [1][2][3][4][5], where they facilitate the uniform temperature and composition of molten steel [3,6], accelerate metallurgical reactions [7][8][9][10][11], promote alloy and scrap melting [12][13][14][15][16], eliminate non-metallic inclusions in the steel [16][17][18][19][20][21], effectively enhance steel product quality [22][23][24], improve ladle refining efficiency [3], and reduce production costs. Over the past several decades, numerous physical models [2,4,7,[25][26][27][28][29][30][31][32] and numerical models [33][34][35][36][37][38][39][40] have been established to investigate fluid flow [41,…”