Nature of dust and smoke generation during gas-oxygen blasting in converter bath

The article presents the study of the nature of dust and smoke generation during gas-oxygen blasting of a converter bath. The main reasons causing metal waste have been determined. Influence of the process main parameters on metal loss has been studied during dust removal and evaporation of iron in the reaction zone. The authors have estimated the process of metal pulverization due to CO bubbles floating, determined by the rate of their rise to the bath surface. Specifics of temperature regime of the reaction zone and heat balance have been determined when adding fuel to the oxygen flow. Adding fuel to oxygen makes it possible to increase heat input into the bath, while reducing the rate of decarburization. This enables reduction of dust discharge during rupture and crush of metal films by gas bubbles. The effect of combustion products oxygen use on metal impurities oxidation is considered. By the example of blasting carbon and alloyed steel for mill rolls, it has been shown that the degrees of CO₂ and H₂O decomposition in the bath are the main qualities of gas-oxygen blasting. These indicators determine the oxidizing and heating properties of the blast. Assessment of change in total, consumed heat and its losses with exhaust gases, depending on degree of the oxygen flow dilution with natural gas (methane), has been carried out. Under these conditions, use of submersible combustion torches with change in their oxidizing ability makes it possible to solve various technological tasks, including provision of an effective way to reduce dust emission in converter process.

1. Baptizmanskii V.I., Medzhibozhskii M.Ya., Okhotskii V.B. Converter Steelmaking Processes. Kiev-Donetsk: Vishcha shkola, 1984, 343 p. (In Russ.).

2. Kolpakov S.V., Starov R.V., Smoktii V.V. etc. Steelmaking Technology in Modern Converter Plants. Moscow: Mashinostroenie, 1991, 464 p. (In Russ.).

3. Baptizmanskii M.I., Boichenko B.M., Cherevko V.P. Thermal Operation of Oxygen Converters. Moscow: Metallurgiya, 1988, 174 p. (In Russ.).

4. Li M., Li L., Zhang B., Li Q., Wu W., Zou Z. Numerical analysis of the particle-induced effect on gas flow in a supersonic powder-laden oxygen jet // Metallurgical and Materials Transactions B: Process Metallurgy and Materials Processing Science. 2020. Vol. 51. No. 4. P. 1718–1730. http://doi.org/10.1007/s11663-020-01855-3

5. Ashrit S., Sarkar S., Chatti R.V., Sarkar C., Sarkar S. Nonmetallic LD slag fines – opportunities by invoking chemistry // Ironmaking and Steelmaking. 2020. Vol. 47. No. 8. P. 903–907. http://doi.org/10.1080/03019233.2019.164167

6. Wang B., Shen S., Ruan Y., Сheng S., Peng W., Zhang J. Simulation of gas-liquid two-phase flow in metallurgical process // Acta Metallurgica Sinica. 2020. Vol. 56. No. 4. P. 619–632. http://doi.org/10.11900/0412.1961.2019.00385

7. Yao L., Zhu R., Tang Y., Wei G., Dong K. Effect of furnace gas composition on characteristics of supersonic oxygen jets in the converter steelmaking process // Materials. 2020. Vol. 13. No. 15. Article 3353. http://doi.org/10.3390/ma13153353

8. Sharma S.K., Hlinka J.W., Kern D.W. The bath circulation, jet penetration and high-temperature reaction zone in BOF steelmaking // Steelmaking Proceedings. 1977. Vol. 60. P. 181–197.

9. Yavoiskii V.I. Theory of Steelmaking Processes. Moscow: Metallurgiya, 1969, 467 p. (In Russ.).

10. Okhotskii V.B. Physicochemical Mechanics of Steelmaking Processes. Moscow: Metallurgiya, 1993, 151 p. (In Russ.).

11. Fedorchenko I.M., Andrievskii S.A. Fundamentals of Powder Metallurgy. Kiev: Izd-vo AN USSR, 1963, 420 p. (In Russ.).

12. Barella S., Mapelli C., Mombelli D., Gruttadauria A., Laghi E., Ancona V., Valentino G. Model for the final decarburisation of the steel bath through a self-bubbling effect // Ironmaking and Steelmaking. 2019. Vol. 46. No. 8. P. 721–724. http://doi.org/10.1080/03019233.2017.1405179

13. Jacobs H. Q-BOP process – after eleven years // Metals. 1973. Vol. 25. No. 3. Р. 33–41.

14. Li W., Zhu R., Feng C., Wei G., Han B. Influence of carrier gas of converter oxygen lance on smooth distribution of O 2 −CO2 −CaO mixed jet // Transactions of the Indian Institute of Metals. 2020. Vol. 73. No. 12. P. 3027–3035. http://doi.org/10.1007/s12666-020-02105-5

15. Osani H., Ohmiya S. Total hot metals pretreatment and BOF operation practice for high purity steelmaking. In: 1 EOS Congress. Düsseldorf, 1993. P. 41–46.

16. Jamamoto Z. Production and technology of iron and steel in Japan during 1993 // ISIJ International. 1994. Vol. 34. No. 4. Р. 229–312. https://doi.org/10.2355/isijinternational.34.299

17. Somways N.L. Development in the North-American iron and steel industry // Iron and Steel Engineering. 1994. Vol. 71. No. 2. P. 1–20.

18. Filippov S.I., Kol’tsov A.T. Oxygen partial pressure distribution along a multiphase blast stream of oxygen converter. Izvestiya. Ferrous Metallurgy. 1979, no. 9, pp. 33–36. (In Russ.).

19. Medzhibozhskii M.Ya. Fundamentals of Thermodynamics and Kinetics of Steelmaking Processes. Kiev-Donetsk: Vishcha shkola, 1979, 277 p. (In Russ.).

20. Protopopov E.V., Solomon G.M., Verevkin G.I. State of slag-metal emulsion and changes in physicochemical properties during melting in an oxygen converter. Izvestiya. Ferrous Metallurgy. 1995, no. 8, pp. 25–27. (In Russ.).

21. Goodman N. Slag splashing of BOF converters. Iron and Steel Inst. 1996, no. XXX, pp. 24–33.

22. Diepmann D., Gharib M. The role of streamwise vortisity in the hear-field entrainment of round jets. Journal of Fluid Mechanics. 1992, vol. 245, pp. 643–668.

23. Protopopov E.V., Aizatulov R.S., Chernyatevich A.G. Technological aspects of combined supply of inert gas to converter bath. In: Papers of the IV International Congress of Steelmakers. Moscow: Chermetinformatsiya, 1997, pp. 104–107. (In Russ.).

24. Protopopov E.V., Chernyatevich A.G., Yudin S.V. Investigation of chemical and temperature gradients in a converter bath using hightemperature modeling. Izvestiya. Ferrous Metallurgy. 1997, no. 10, pp. 20–24. (In Russ.).

25. Lushka A.I. Fundamentals of Chemical Thermodynamics and Kinetics of Chemical Reactions. Moscow: Mashinostroenie, 1981, 240 p. (In Russ.).

26. Karp I.N., Soroka B.S., Dashevskii L.N., Semernina D. Products of Natural Gas Combustion at High Temperatures. Kiev: Tekhnika, 1967, 381 p. (In Russ.).