Simulation study on factors influencing the entrainment behavior of liquid steel as bubbles pass through the steel/slag interface

Abstract

In this study, a water/silicone oil interface was used to simulate the steel/slag interface in a converter. A high-speed camera was used to record the entrainment process of droplets when air bubbles were passed through the water/silicone oil interface. Motion parameters of the bubbles and droplets were obtained using particle kinematic analysis software, and the entrainment rate of the droplets was calculated. It was found that the entrainment rate decreased from 29.5% to 0 when the viscosity of the silicone oil was increased from 60 mPa·s to 820 mPa·s in the case of bubbles with a 5 mm equivalent diameter passing through the water/silicone oil interface. The results indicate that increasing the viscosity of the silicone oil is conducive to reducing the entrainment rate. The entrainment rate increased from 0 to 136.3% in the case of silicone oil with a viscosity of 60 mPa·s when the equivalent diameter of the bubbles was increased from 3 mm to 7 mm. We therefore conclude that small bubbles are also conductive to reducing the entrainment rate. The force analysis results for the water column indicate that the entrainment rate of droplets is affected by the velocity of the bubble passing through the water/silicone oil interface and that the entrainment rate decreases with the bubble velocity.

Keywords

steelmaking / bubbles / interfaces / entrainment / influencing factors / simulation studies

References

[1] Ito K., Fruehan R.J. Study on the foaming of CaO?SiO2?FeO slags: Part I. Foaming parameters and experimental results. Metall. Mater. Trans. B, 1989, 20(4): 509.

[2] Ito K., Fruehan R.J. Study on the foaming of CaO? SiO2?FeO slags: Part II. Dimensional analysis and foaming in iron and steelmaking processes. Metall. Mater. Trans. B, 1989, 20(4): 515.

[3] Liu Z., Shao N.N., Huang T.Y., Qin J.F., Wang D.M., Yang Y. Effect of SiO2/Na2O mole ratio on the properties of foam geopolymers fabricated from circulating fluidized bed fly ash. Int. J. Miner. Metall. Mater., 2014, 21(6): 620.

[4] Lahiri A.K., Seetharaman S. Foaming behavior of slags. Metall. Mater. Trans. B, 2002, 33(3): 499.

[5] Zhu T.X., Coley K.S., Irons G.A. Progress in slag foaming in metallurgical processes. Metall. Mater. Trans. B, 2012, 43(4): 751.

[6] Yamashita K., Sukenaga S., Matsuo M., Saito N., Nakashima K. Rheological behavior and empirical model of simulated foaming slag. ISIJ Int., 2014, 54(9): 2064.

[7] Davydenko A., Karasev A., Lindstrand G., Jönsson P. Investigation of slag foaming by additions of briquettes in the EAF during stainless steel production. Steel Res. Int., 2015, 86(2): 146.

[8] Kim H.S., Min D.J., Park J.H. Foaming behavior of CaO?SiO2?FeO?MgOsatd?X (X = Al2O3. MnO, P2O5, and CaF2) slags at high temperature, ISIJ Int., 2001, 42(4): 317.

[9] Cui Y., Nan X.D., Feng J., Chun C.L., Zhou D.G., Zhu L.X. Technology of foaming slag level control during latter period of blowing for BOF process. Steelmaking, 2010, 26(2): 70.

[10] Lu K., Li J.Z. Effect of oxygen used in steel-making on splash in converter. Steelmaking, 2009, 25(6): 20.

[11] Zhu Y.X., Zhong L.C., Xiao Z.M. Application and development of deep dephosphorization technology in top and bottom combination blown converters. Steelmaking, 2013, 29(4): 1.

[12] Wang X.H., Zhu G.S., Li H.B., Lü Y.C. Investigation on “slag-remaining + double-slag” BOF steelmaking technology. China Metall., 2013, 23(4): 40.

[13] Zheng S.G., Zhu M.Y. Physical modeling of gas?liquid interfacial fluctuation in a thick slab continuous casting mold with argon blowing. Int. J. Miner. Metall. Mater., 2010, 17(6): 704.

[14] Sulasalmi P., Visuri V.V., Fabritius T. Simulation of the effect of steel flow velocity on slag droplet distribution and interfacial area between steel and slag. Steel Res. Int., 2015, 86(3): 212.

[15] Strandh J., Nakajima K., Eriksson R., Jönsson P. A mathematical model to study liquid inclusion behavior at the steel?slag interface. ISIJ Int., 2005, 45(12): 1838.

[16] Han Z.J., Holappa L. Mechanisms of iron entrainment into slag due to rising gas bubbles. ISIJ Int., 2003, 43(3): 292.

[17] Reiter G., Schwerdtfeger K. Observations of physical phenomena occurring during passage bubbles through liquid/ liquid Interfaces. ISIJ Int., 1992, 32(1): 50.

[18] Reiter G., Schwerdtfeger K. Characteristics of entrainment at liquid/liquid interfaces due to rising bubbles. ISIJ Int., 1992, 32(1): 57.

[19] Wang J.J., Bao Y.P., Qu Y. Tundish Metallurgy, 2001, Beijing, The Metallurgical Industry Press, 394.

[20] Xiao X.G., Xie Y.G. Foundation of Metallurgical Reaction Engineering, 1997, Beijing, The Metallurgical Industry Press, 381.