Advertisement

In Situ Monitoring of Pit Gas Composition During Baking of Anodes for Aluminum Electrolysis

  • Trond Brandvik
  • Heiko Gaertner
  • Arne P. Ratvik
  • Tor Grande
  • Thor A. AarhaugEmail author
Article
  • 46 Downloads

Abstract

Carbon anodes, which are consumed in aluminum electrolysis, are fabricated in separate anode plants where coke and pitch are mixed and vibrocompacted to green anode blocks before being baked in anode baking furnaces. The chemical environment inside an anode baking furnace is found to play an important role in the degradation of the furnace refractory lining. In this work, the pit gas composition was recorded during anode baking by a Fourier transformed infrared spectroscopy (FTIR) spectrometer and a gas chromatograph. The temperature dependence of the concentration of gas species during baking was obtained based on three measurement campaigns. The concentrations of CO and CO2 were found to be dependent on temperature, where the concentration of CO peaked around the maximum firing temperature. In addition to varying concentrations of CH4 and HF, water was found in large amounts in the first part of the baking cycle. The water originates to some extent from the cooling of the green anodes after vibrocompaction and is potentially important with respect to the chemical stability of the refractory lining. The variations in pit gas composition are related to operational parameters and are discussed in relation to refractory degradation phenomena.

Notes

Acknowledgments

Financial support from the Norwegian Research Council and the partners Hydro Aluminium, Alcoa, Elkem Carbon, and Skamol through the project “Reactivity of Carbon and Refractory Materials used in metal production technology” (CaRMa) is acknowledged. Technical support from Roger Moen, Morten Aanvik, Martin Aufles, Mona Aufles Hines, and the other staff at Alcoa Mosjøen during the measuring campaigns is acknowledged and highly appreciated.

References

  1. 1.
    E.H.M. Moors: J. Clean. Prod., 2006, vol. 14, pp. 1121–38.CrossRefGoogle Scholar
  2. 2.
    H.-G. Schwarz, S. Briem, and P. Zapp: Energy, 2001, vol. 26, pp. 775–95.CrossRefGoogle Scholar
  3. 3.
    F. Becker and F. Goede: Ring Pit Furnace for Baking of High Quality Anodes—An Overview, Riedhammer, Nürnberg, 2006. http://www.riedhammer.de/system/00/01/42/14219/633776329561250000_1.pdf. Accessed 7 Dec 2018.
  4. 4.
    P. Prigent and M.L. Bouchetou: Interceram, 2009, vol. 58, pp. 202–09.Google Scholar
  5. 5.
    P. Prigent and M.L. Bouchetou: Interceram, 2009, vol. 58, pp. 121–26.Google Scholar
  6. 6.
    T. Brandvik, A.P. Ratvik, Z. Wang, and T. Grande: Light Metals, Springer, Cham, 2017, pp. 1281–88.CrossRefGoogle Scholar
  7. 7.
    T. Brandvik, A.P. Ratvik, and T. Grande: Travaux 45, CB11, Proc. 34th Int. ICSOBA Conf. 2016.Google Scholar
  8. 8.
    T. Brandvik, Z. Wang, A.P. Ratvik, and T. Grande: Int. J. Appl. Ceram. Technol., 2018.  https://doi.org/10.1111/ijac.13108.CrossRefGoogle Scholar
  9. 9.
    F. Brunk: Light Metals, TMS, Warrendale, PA, 1995, pp. 641–46.Google Scholar
  10. 10.
    N. Oumarou, D. Kocaefe, and Y. Kocaefe: Ceram. Int., 2016, vol. 42, pp. 18436–42.CrossRefGoogle Scholar
  11. 11.
    T.A. Aarhaug, T. Brandvik, O.S. Kjos, H. Gaertner, and A.P. Ratvik: Light Metals, Springer, Cham, 2018, pp. 1379–85.Google Scholar
  12. 12.
    T.A. Aarhaug, T. Brandvik, H. Gaertner, A.P. Ratvik, and O.S. Kjos: Proc. 12th Australasian Aluminium Smelting Technology Conf. 2018.Google Scholar
  13. 13.
    D. Trommer, D. Hirsch, and A. Steinfeld: Int. J. Hydrogen Energy, 2004, vol. 29, pp. 627–33.CrossRefGoogle Scholar
  14. 14.
    F. Grégoire and L. Gosselin: Int. J. Therm. Sci., 2018, vol. 129, pp. 532–44.CrossRefGoogle Scholar
  15. 15.
    T. Brandvik, A.P. Ratvik, and T. Grande: Travaux 47, CB06, Proc. 36th Int. ICSOBA Conf. 2018, pp. 555–62.Google Scholar
  16. 16.
    Z. Wang, S. Rørvik, A.P. Ratvik, and T. Grande: Light Metals, Springer, Cham, 2017, pp. 1265–74.CrossRefGoogle Scholar
  17. 17.
    C. Sommerseth, R. Thorne, A. Ratvik, E. Sandnes, H. Linga, L. Lossius, and A. Svensson: Metals (Basel), 2017, vol. 7, p. 74.CrossRefGoogle Scholar

Copyright information

© The Minerals, Metals & Materials Society and ASM International 2019

Authors and Affiliations

  • Trond Brandvik
    • 1
  • Heiko Gaertner
    • 2
  • Arne P. Ratvik
    • 2
  • Tor Grande
    • 1
  • Thor A. Aarhaug
    • 2
    Email author
  1. 1.Department of Materials Science and EngineeringNTNU Norwegian University of Science and TechnologyTrondheimNorway
  2. 2.SINTEF IndustryTrondheimNorway

Personalised recommendations