Diffusion and Flow of CO2 in Carbon Anode for Aluminium Smelting

  • Epma PutriEmail author
  • Geoffrey Brooks
  • Graeme A. Snook
  • Ingo Eick
  • Lorentz Petter Lossius


Using a well-made carbon anode with the right porosity characteristics is essential to the successful operation of a Hall–Héroult cell. Bubble generation at this carbon anode and its contribution to the overall voltage drop in aluminum production holds significant potential for reducing overpotential and improving energy savings. This voltage drop is believed to be greatly influenced by the gas diffusion in the anode carbon, for which there are a limited number of measurements to correlate with the carbon anode properties. In the present study, the CO2 gas diffusion characteristics were first investigated via measuring anode porosity using mercury intrusion porosimetry (MIP) for different samples with different permeability. Second, diffusion experiments were conducted by flowing CO2 gas into the anode sample at elevated temperatures (up to 960 °C). The impact of temperature, average pore size, and permeability on the diffusion coefficient was investigated. The diffusion coefficient was consequently calculated by curve fitting using diffusion theories. The value obtained varied from 1.38 × 10−6 to 7.89 × 10−6 m2/s. A high diffusion coefficient was measured in the carbon sample with larger average pore size and higher permeability. It was found that anomalous diffusion behavior in the temperature range 600 °C to 960 °C was caused by convective flow effects, different diffusion mechanisms, and the Boudouard reaction for these carbon anode samples. Furthermore, by plotting the measured diffusion coefficient against average pore size and permeability, an increasing trend of diffusivity with an increase in pore size and permeability was observed.



The present work was supported and financed by Hydro Aluminium and the Norwegian Research Council. Permission to publish the results is gratefully acknowledged.


  1. 1.
    S. Poncsák and L.I. Kiss: Light Metals, 2012, pp. 773–78.Google Scholar
  2. 2.
    K.E. Einarsrud, S.T. Johansen, and I. Eick: Light Metals, 2012, pp. 875–80.Google Scholar
  3. 3.
    E. Golovina: Dokl. Akad. Nauk CCCR, 1952, pp. 141–43.Google Scholar
  4. 4.
    T. Perkins and O. Johnston: Soc. Petrol. Eng. J., 1963, vol. 3, pp. 70–84.CrossRefGoogle Scholar
  5. 5.
    W. He, J. Zou, B. Wang, S. Vilayurganapathy, M. Zhou, X. Lin, K.H. Zhang, J. Lin, P. Xu, and J.H. Dickerson: J. Power Sources, 2013, vol. 237, pp. 64–73.CrossRefGoogle Scholar
  6. 6.
    S.W. Webb and K. Pruess: Transp. Porous Media, 2003, vol. 51, pp. 327–41.CrossRefGoogle Scholar
  7. 7.
    R. Krishna and J. Wesselingh: Chem. Eng. Sci., 1997, vol. 52, pp. 861–911.CrossRefGoogle Scholar
  8. 8.
    A. Berson, H.-W. Choi, and J.G. Pharoah: Phys. Rev. E, 2011, vol. 83, art. no. 026310.Google Scholar
  9. 9.
    Z. Gao: Ph.D. Thesis, University of Texas, USA, 2014, pp. 34–36.Google Scholar
  10. 10.
    S. Satoh, I. Matsuyama, and K. Susa: J. Non-Cryst. Solids, 1995, vol. 190, pp. 206–10.CrossRefGoogle Scholar
  11. 11.
    A. Radjenovic: Nafta, 2012, vol. 63, pp. 111–14.Google Scholar
  12. 12.
    F.A. Dullien: Porous Media: Fluid Transport and Pore Structure, Academic Press, 2012, pp. 5–11.Google Scholar
  13. 13.
    P.A. Webb: Micromeritics Instrument Corporation, Norcross, GA, 2001, pp. 4–9.Google Scholar
  14. 14.
    E. Putri, G. Brooks, G.A. Snook, S. Rørvik, L.P. Lossius, and I. Eick: Light Metals, 2018, pp. 1235–42.Google Scholar
  15. 15.
    K. Azari, H. Alamdari, G. Aryanpour, D. Picard, M. Fafard, and A. Adams: Powder Technol., 2013, vol. 235, pp. 341–48.CrossRefGoogle Scholar
  16. 16.
    Z. Nie and Y. Lin: Ceramics-Silikáty, 2015, vol. 59, pp. 348–52.Google Scholar
  17. 17.
    Z. Yu, R. Carter, and J. Zhang: Fuel Cells, 2012, vol. 12, pp. 557–61.CrossRefGoogle Scholar
  18. 18.
    J. Kärger and D.M. Ruthven: Handbook of Porous Solids, 2002, pp. 2087–173.Google Scholar
  19. 19.
    H.A. Øye: Fundamental Issues in Control of Carbon Gasification Reactivity, Springer, 1991, pp. 573–94.Google Scholar
  20. 20.
    J.F.R. Boero: Essential Readings in Light Metals: Electrode Technology for Aluminum Production, 2013, vol. 4, pp. 580–85.Google Scholar
  21. 21.
    B. Sadler and S. Algie: Essential Readings in Light Metals: Electrode Technology for Aluminum Production, 2013, vol. 4, pp. 594–600.Google Scholar
  22. 22.
    T. Chen, J. Xue, G. Lang, R. Liu, S. Gao, and Z. Wang: JOM, 2017, vol. 69, pp. 1600–04.CrossRefGoogle Scholar
  23. 23.
    M.A. Engvoll: Ph.D. Thesis, Norwegian University of Science and Technology, 2002, pp. 52–59.Google Scholar
  24. 24.
    D. Bhattacharyay, D. Kocaefe, Y. Kocaefe, and B. Morais: J. Surf. Eng. Mater. Adv. Technol., 2013, vol. 3, pp. 1–5.Google Scholar
  25. 25.
    K. Azari, H. Alamdari, G. Aryanpour, D. Ziegler, D. Picard, and M. Fafard: Powder Technol., 2013, vol. 246, pp. 650–55.CrossRefGoogle Scholar

Copyright information

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

Authors and Affiliations

  • Epma Putri
    • 1
    • 2
    Email author
  • Geoffrey Brooks
    • 1
  • Graeme A. Snook
    • 2
  • Ingo Eick
    • 3
  • Lorentz Petter Lossius
    • 4
  1. 1.Faculty of Science, Engineering and TechnologySwinburne University of TechnologyHawthornAustralia
  2. 2.CSIRO, Mineral ResourcesClaytonAustralia
  3. 3.Hydro Aluminium Deutschland GmbHNeussGermany
  4. 4.Hydro Aluminium ASØvre ÅrdalNorway

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