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Steel in Translation

, Volume 48, Issue 3, pp 168–172 | Cite as

Surface Phenomena in the Smelting Bath of an Oxygen Converter

  • N. E. Khisamutdinov
  • O. V. Yavoiskaya
  • A. V. Yavoiskii
  • S. N. Khisamutdinov
Article

Abstract

The oxygen-converter production of steel is determined by processes in the converter’s reaction zone, which consists of primary and secondary regions. The primary region is the crater formed by the collision of a supersonic gas jet with the molten-metal surface. It is filled with metal droplets (diameter 0.1–2 mm). The surrounding secondary region consists of melt with an enormous quantity of gas bubbles (diameter 0.2–4 mm). The total surface area of the droplets and bubbles is four orders of magnitude greater than the surface of the quiescent melt. That indicates the important role of processes at phase boundaries in steel production. The structure of the reaction zone and the corresponding temperature distribution are studied by hot simulation, when the molten metal is blown by oxygen in a transparent quartz crucible. The transparent walls permit photographic and video recording of the processes in the crucible. Besides the temperature distribution, the hydrodynamics of the bath may be studied directly in the injection zone. The most unexpected result of hot simulation is the motion of the bubbles in the secondary region. They move normal to the crater surface. In other words, their motion is almost horizontal, rather than vertical, as in cold simulation in water. This may be attributed to nonuniformity of the melt’s surface tension, resulting in motion of the bubbles toward higher temperatures. In liquid with a temperature gradient, the surface tension will be different ahead of and behind the bubbles. The forces pushing the bubbles from behind are greater than the forces at the front. Accordingly, they move toward the region of lower surface tension. The nonuniformity of the surface tension is due to the temperature gradient (up to 1200°C within the secondary region) and the change in concentration of the melt components, especially oxygen. The surface tension of the ferrocarbon melt changes in a complex manner with increase in temperature. The surface tension rises on heating to 1550°C, but begins to decrease beyond 1550–1600°C. With decrease in carbon content in the melt, the maximum value of the surface tension increases. The motion of gas bubbles and other phases toward lower surface tension begins at the 1550°C isotherm, which is therefore the external boundary of the secondary region, separating it from the remainder of the bath. Within this boundary, the resultant vector of the surface forces pushes the gas bubbles and slag particles, together with the molten metal, horizontally toward the crater, at increasing speed. This determines the hydrodynamics of the smelting bath and the associated redistribution of oxygen over different parts of the bath and hence the refining process as a whole.

Keywords

reaction zone primary region secondary region hot simulation temperature gradient surface tension molten metal gas bubbles metal droplets bath hydrodynamics 

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References

  1. 1.
    Yavoiskii, V.I., Dorofeev, G.A., and Povkh, I.L., Teoriya produvki staleplavil’noi vanny (Theory of Steelmaking Bath Blow), Moscow: Metallurgiya, 1974.Google Scholar
  2. 2.
    Baptizmanskii, V.I. and Okhotskii, V.B., Fiziko-khimicheskie osnovy kislorodno-konverternogo protsessa (Physical and Chemical Foundations of Steelmaking Process), Kiev: Vishcha Shkola, 1981.Google Scholar
  3. 3.
    Khisamutdinov, N.E., Yavoiskii, A.V., and Grebenyuk, N.A., Thermocapillarity phenomena at metal melts blow, Izv. Akad. Nauk SSSR, Rasplavy, 1989, vol. 3, no. 2, pp. 3–8.Google Scholar
  4. 4.
    Yavoiskaya, O.V., Yavoiskii, A.V., Khisamutdinov, N.E., and Khisamutdinov, S.N., Temperature of BOF reaction zone, Trudy XIRossiiskoi konferentsii “Stroenie i svoistva metallicheskikh rasplavov” (Proc. XI Russ. Conf. “Structure and Properties of Metal Melts”), Chelyabinsk: Yuzh.-Ural. Gos. Univ., 2004, vol. 2, pp. 248–250.Google Scholar
  5. 5.
    Yavoiskii, V.I. and Yavoiskii, A.V., Nauchnye osnovy sovremennykh protsessov proizvodstva stali (Scientific Foundation of Modern Steelmaking), Moscow: Metallurgiya, 1987, 184 p.Google Scholar
  6. 6.
    Baptizmanskii, V.I., Mekhanizm i kinetika protsessov v konverternoi vanne (Mechanism and Kinetics of Converter Bath Processes), Moscow: Metallurgizdat, 1960.Google Scholar
  7. 7.
    Surin, V.A. and Nazarov, N.N., Masso- i teploobmen, gidrodinamika metallicheskoi vanny (Mass- and Heat Exchange, Hydrodynamics of Metal Bath), Moscow: Metallurgiya, 1993.Google Scholar
  8. 8.
    Yavoiskaya, O.V., Khisamutdinov, N.E., Yavoiskii, A.V., and Khisamutdinov, S.N., Thermocapillarity phenomenon at BOF process, Trudy XIII Rossiiskoi konferentsii “Stroenie i svoistva metallicheskikh i shlakovykh rasplavov” (Proc. XIII Russ. Conf. “Structure and Properties of Metal and Slag Melts”), Yekaterinburg: Ural. Otd., Ross. Akad. Nauk, 2011, vol. 2, pp. 186–189.Google Scholar
  9. 9.
    Adamson, A.W., Physical Chemistry of Surfaces, NewYork: Wiley, 1982.Google Scholar
  10. 10.
    Jaycock, M.J. and Parfitt, G.D., Chemistry of Interfaces, Chichester: Ellis Horwood, 1981.Google Scholar
  11. 11.
    Popel’, S.I., Surface phenomena at steelmaking processes, in Fiziko-khimicheskie osnovy protsessov proizvodstva stali (Physical and Chemical Foundation of Steelmaking), Moscow: Nauka, 1979, pp. 71–79.Google Scholar
  12. 12.
    Popel’, S.I., Poverkhnostnye yavleniya v rasplavakh (Surface Phenomena in Melts), Moscow: Metallurgiya, 1994.Google Scholar
  13. 13.
    Elanskii, G.N. and Kudrin, V.A., Stroenie i svoistva zhidkogo metalla–tekhnologiya plavki–kachestvo stali (Structure and Properties of Liquid Metal–Melting Technology–Steel Quality), Moscow: Metallurgiya, 1984.Google Scholar
  14. 14.
    Nizhenko, V.I. and Floka, L.I., Poverkhnostnoe natyazhenie zhidkikh metallov i splavov (odno- i dvukhkomponentnye sistemy). Spravochnik (Surface Tension of Metals and Alloys (Mono- and Two-Component Systems). Handbook), Moscow: Metallurgiya, 1981.Google Scholar
  15. 15.
    March, N.H., Liquid Metals, New York: Pergamon, 1968.Google Scholar
  16. 16.
    Ershov, G.S. and Bychkov, Yu.B., Svoistva metallicheskikh rasplavov i ikh vzaimodeistvie v staleplavil’nykh protsessakh (Properties of Metal Melts and Their Interaction at Steelmaking), Moscow: Metallurgiya, 1983.Google Scholar
  17. 17.
    Arsent’ev, P.P. and Koledov, L.A., Metallicheskie rasplavy i ikh svoistva (Metal Melts and Their Properties), Moscow: Metallurgiya, 1976.Google Scholar
  18. 18.
    Frank-Kamenetskii, D.A., Diffuziya i teploperedacha v khimicheskoi kinetike (Diffusion and Heat Transfer in Chemical Kinetics), Moscow: Nauka, 1967, 2nd ed.Google Scholar
  19. 19.
    Popel’, S.I., Nikitin, Yu.P., Barmin, L.A., et al., Vzaimodeistvie rasplavlennogo metalla s gazom i shlakom (Metal Melt Interaction with Gas and Slag), Sverdlovsk: Ural. Politekh. Inst. im. C.M. Kirova, 1975.Google Scholar
  20. 20.
    The Structure of Liquid Metals and Alloys, Wilson, J.R., Ed., London: Inst. Met., 1966.Google Scholar
  21. 21.
    Baum, B.A., Khasin, G.A., Tyagunov, G.V., et al., Zhidkaya stal’ (Liquid Steel), Moscow: Metallurgiya, 1984.Google Scholar

Copyright information

© Allerton Press, Inc. 2018

Authors and Affiliations

  • N. E. Khisamutdinov
    • 1
  • O. V. Yavoiskaya
    • 1
  • A. V. Yavoiskii
    • 2
  • S. N. Khisamutdinov
    • 3
  1. 1.Ural State Agrarian UniversityYekaterinburgRussia
  2. 2.Moscow Institute of Steel and AlloysMoscowRussia
  3. 3.OOO Siti RapidMoscowRussia

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