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Volatilization behaviour and volatilization kinetics of CaF2–Na2O–CaO–SiO2–Al2O3–MgO–B2O3 synthetic mould flux

  • Ya-ru Cui
  • Hao-yue Fan
  • Zi-liang Guo
  • Guo-hua Wang
  • Xiao-ming LiEmail author
  • Jun-xue ZhaoEmail author
  • Ze Yang
Original Paper
  • 13 Downloads

Abstract

To reduce the volatilization of the volatile-containing slags and obtain accurate measurement results of slag performance, the volatility degree and deviation mechanism must be determined. Non-isothermal thermogravimetric analysis at different heating rates was used to establish the volatilization kinetic model, and it reveals the volatilization mechanism of CaF2–Na2O–CaO–SiO2–Al2O3–MgO–B2O3 synthetic sodium-containing fluoride mould flux. The results demonstrated that the evaporation of NaF and SiF4 was the decisive factor that led to the change in composition and deviation of properties of the tested slags. The most probable kinetic mechanism function for the evaporation of volatile component from sodium-containing fluoride mould flux could be expressed by \(g(\alpha ) = [ - \ln (1 - \alpha )]^{2/3}\), with an apparent activation energy of 164.866 kJ mol−1 and pre-exponential factor of 2.13 × 10−4 s−1, where α is the conversion rate at any time step in the volatilization process. The reaction mechanism was random nucleation followed by growth, which was the limiting factor for the volatilization of synthetic sodium-containing fluoride mould flux. The method of increasing heating rate and adding protection gas in the measurement system will help to obtain more accurate results of slag performance.

Keywords

Fluoride Slag performance Volatilization kinetics Thermogravimetric analysis Mechanism function 

Notes

Acknowledgements

The authors thank the National Natural Science Foundation of China (Nos. 51674186, 51674185 and 51574189), the Science Foundation of Shaanxi Province (No. 2018JM5104) for financial support and Dr. Chong Zou for the help in theoretical analysis for volatilization kinetics.

References

  1. [1]
    K. Mills, Treatise on Process Metallurgy 3 (2014) 435–475.Google Scholar
  2. [2]
    T.J.H. Billany, A.S. Normanton, K.C. Mills, Ironmak. Steelmak. 18 (1991) 403–410.Google Scholar
  3. [3]
    E. Brandaleze, G.D. Gresia, L. Santini, A. Martín, E. Benavidez, Science and Technology of Casting Processes 9 (2012) 205–234.Google Scholar
  4. [4]
    J.A. Kromhout, A.A. Kamperman, M. Kick, J. Trouw, Ironmak. Steelmak. 32 (2005) 127–132.Google Scholar
  5. [5]
    K.Y. Ko, J.H. Park, ISIJ Int. 53 (2013) 958–965.Google Scholar
  6. [6]
    K.C. Mills, A.B. Fox, Z. Li, R.P. Thackray, Ironmak. Steelmak. 32 (2005) 26–34.Google Scholar
  7. [7]
    A. Ahmadreza, A. Monshi, T. Khayamian, A. Saidi, Engineering 4 (2012) 435–444.Google Scholar
  8. [8]
    Q. Wang, D. Xie, S.P. He, P. Wang, J. Iron Steel Res. 19 (2007) No. 6, 38–41.Google Scholar
  9. [9]
    L. Wang, Y.R. Cui, J. Yang, C. Zhang, D.X. Cai, J.Q. Zhang, Y. Sasaki, O. Ostrovski, Steel Res. Int. 86 (2015) 670–677.Google Scholar
  10. [10]
    J.L. Klug, D.R. Silva, S.L. Freitas, M.M.S.M. Pereira, N.C. Heck, A.C.F. Vilela, D. Jung, Steel Res. Int. 83 (2012) 791–799.Google Scholar
  11. [11]
    K. Shimizu, A.W. Cramb, High Temp. Mater. Processes 22 (2003) 237–245.Google Scholar
  12. [12]
    M. Persson, S. Sridhar, S. Seshadri, ISIJ Int. 47 (2007) 1711–1717.Google Scholar
  13. [13]
    C.B. Shi, J.W. Cho, D.L. Zheng, J. Li, Int. J. Miner. Metall. Mater. 23 (2016) 627–636.Google Scholar
  14. [14]
    J.X. Zhao, Y.M. Chen, X.M. Li, Y.R. Cui, X.T. Lu, J. Iron Steel Res. Int. 18 (2011) No. 10, 24–28, 58.Google Scholar
  15. [15]
    H.M. Liang, Evaporation mechanism of fluorides in slag during electroslag remelting process, Xi’an University of Architecture and Technology, Xi’an, 2013.Google Scholar
  16. [16]
    F. Zhang, S.L. An, Y.C. Wang, G.P. Luo, X.L. Song, J. Iron Steel Res. Int. 22 (2015) 213–218.Google Scholar
  17. [17]
    J.T. Ju, Z.L. Lv, Z.Y. Jiao, J.X. Zhao, Chin. J. Process Eng. 12 (2012) 618–624.Google Scholar
  18. [18]
    Z.R. Hu, Q.Z. Shi, Thermal analysis kinetics, Science Press, Beijing, 2008.Google Scholar
  19. [19]
    C. Liu, J.H. Peng, A.Y. Ma, L.B. Zhang, J. Li, J. Hazardous Mater. 322 (2017) 325–333.Google Scholar
  20. [20]
    T. Ozawa, J. Thermal Analysis Calorimetry 2 (1970) 301–324.Google Scholar
  21. [21]
    O. Takeo, Bull. Chem. Soc. Jpn. 38 (1965) 1881–1886.Google Scholar
  22. [22]
    X.C. Li, B.S. Nie, R.M. Zhang, L.L. Chi, Int. J. Min. Sci. Technol. 22 (2012) 885–889.Google Scholar
  23. [23]
    Y.W. Liu, J.P. Wei, Z.G. He, M.J. Liu, J. China Coal Soc. 38 (2013) S1, 100–105.Google Scholar
  24. [24]
    C.W. Bale, E. Bélisle, P. Chartrand, S.A. Decterov, G. Eriksson, A.E. Gheribi, K. Hack, I.H. Jung, Y.B. Kang, J. Melançon, A.D. Pelton, S. Petersen, C. Robelin, J. Sangster, P. Spencer, M.A. Van Ende, Calphad 54 (2016) 35–53.Google Scholar
  25. [25]
    L.N. Liu, L. Liu, Z.Y. Liu, X.L. Han, Z.M. Li, Steelmaking 30 (2014) No. 2, 66–69.Google Scholar

Copyright information

© China Iron and Steel Research Institute Group 2019

Authors and Affiliations

  1. 1.School of Metallurgical EngineeringXi’an University of Architecture and TechnologyXi’anChina
  2. 2.Inner Mongolia Xinchuang Resources Recycling Co., Ltd.OrdosChina

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