Direct Carbothermic Reduction of Weathered Ilmenite for Efficient Removal of Iron by Leaching

  • Navneet Singh Randhawa
  • Sanjay PrasadEmail author


The commercial processes to extract iron from ilmenite (FeTiO3) essentially include energy-intensive methods, such as high-temperature reduction smelting or preoxidation, coupled with reduction by carbon. However, due to altered mineralogy of ilmenite caused by weathering at sea coast, the reduction of iron remains incomplete in either of these processes, demanding a high concentration of acid when used for extraction of high-purity TiO2 for high-end applications. We developed a process for the flux-catalyzed reduction of a partially weathered ilmenite ore of Indian origin. Initially, the effect of flux material and temperature was evaluated using thermogravimetric/diffraction thermal analysis (TG/DTA). The reduction behavior of the fluxed self-reducing pellets of ilmenite was then studied in a raising hearth furnace. The TG/DTA results indicated improved performance of sodium carbonate over lime within a temperature range of 1173 K to 1373 K. Under different reduction conditions in raising hearth furnace experiments, the leaching of reduced ilmenite in diluted hydrochloric acid (6.6 pct concentration) produced different grades of synthetic rutile. The best reduction conditions under optimized parameters enhanced the TiO2 from initial 51 to 93 wt pct in the synthetic rutile. The X-ray diffraction and electron probe microanalysis investigation of the unreduced and reduced ilmenite revealed the conversion of the FexOy-SiO2-Al2O3 system to Na2O-SiO2-Al2O3 by sodium carbonate. The thermochemical analysis further explained the influence of sodium carbonate on the liquidus of Na2O-SiO2-Al2O3 slag. The improved process enables the complete reduction of the iron from weathered ilmenite to produce a high-grade rutile.



This work was financially supported by the In-house Project Support Group (iPSG) of CSIR-NML, Jamshedpur.

Supplementary material

11663_2019_1544_MOESM1_ESM.docx (362 kb)
Supplementary material 1 (DOCX 361 kb)


  1. 1.
    G. Chen, Z. Song, J. Chen, J. Peng, and C. Srinivasakannan: J. Alloys Compd., 2013, vol. 577, pp. 610–14.CrossRefGoogle Scholar
  2. 2.
    H.S. Ray, R. Sridhar, and A.P. Abraham: Text Book of Extraction of Non-ferrous Metals, East-West Press Limited, 1985.Google Scholar
  3. 3.
    U. Diebold: Surf. Sci. Rep., 2003, vol. 48, pp. 53–229.CrossRefGoogle Scholar
  4. 4.
    S. Sanchez-Segado, T. Makanyire, L. Escudero-Castejon, Y. Hara, and A. Jha: Green Chem., 2015, vol. 17, pp. 2059–80.CrossRefGoogle Scholar
  5. 5.
    W. Zhang, Z. Zhu, and C.-Y. Cheng: Hydrometallurgy, 2013, vol. 108, pp. 177–88.CrossRefGoogle Scholar
  6. 6.
    F. Habashi: Handbook of Extractive Metallurgy, Wiley-VCH, Weinheim, Germany, 1997, vol. 2, p. 1135.Google Scholar
  7. 7.
    M. Sundararajan, K.H. Bhat, S. Velusamy, N. Babu, M.E.K. Janaki, S. Sasibhooshanan, and P.N. Mohan Das: J. Miner. Mater. Charact. Eng., 2009, vol. 8, pp. 427–38.Google Scholar
  8. 8.
    E.A. Abdel-Aal, I.A. Ibrahim, A.A.I. Afifi, and A.K. Ismail: in 2nd International Conference on Processing Materials for Properties, B. Mishra and C. Yamauchi, eds., TMS, Warrendale, PA, 2000, pp. 955–60.Google Scholar
  9. 9.
    T. Chernet: Chron. Resch. Min., 1999, vol. 535, pp. 19–28.Google Scholar
  10. 10.
    C.S. Kucukkaragoz and R.H. Eric: Miner. Eng., 2006, vol. 19, pp. 334–37.CrossRefGoogle Scholar
  11. 11.
    T. Chernet: Miner. Eng., 1999, vol. 12, pp. 485–95.CrossRefGoogle Scholar
  12. 12.
    S.K. Gupta, V. Rajakumar, and P. Grieveson: Metall. Trans. B, 1988, vol. 20B, pp. 735–45.Google Scholar
  13. 13.
    S.Z. El-Tawil, I.M. Morsi, A. Yehia, and A.A. Francis: Can. Met. Q., 1996, vol. 35, 31–37.CrossRefGoogle Scholar
  14. 14.
    M. Sankar, N.K. Batra, R. Shekhar, and S.P. Mehrotra: Trans. Ind. Inst. Met., 2006, vol. 59, pp. 381–87.Google Scholar
  15. 15.
    J. Moon and V. Sahajwalla: Metall. Mater. Trans. B, 2006, vol. 37B, pp. 215–21.CrossRefGoogle Scholar
  16. 16.
    J. Bao, Z. Li, and N. Cai: Ind. Eng. Chem. Res., 2013, vol. 52, pp. 6119–28.CrossRefGoogle Scholar
  17. 17.
    J. Bao, Z. Li, and N. Cai: Ind. Eng. Chem. Res., 2013, vol. 52, pp. 10646–10655.CrossRefGoogle Scholar
  18. 18.
    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, and M.-A. VanEnde: Calphad, 2016, vol. 54, pp. 35–53.CrossRefGoogle Scholar
  19. 19.
    F.N. Howell: Standard Methods of Chemical Analysis, The Elements, 6th ed., Robert E. Krieger Publishing Company, New York, NY, 1975, vol. 1, p. 1119.Google Scholar
  20. 20.
    D.S. Rao, T.V. Vijayakumar, S. Prabhakar, G. Bhaskar Raju, and T.K. Ghosh: J. Miner. Mater. Charact. Eng., 2005, vol. 4, pp. 47–59.Google Scholar
  21. 21.
    M.T. Frost, I.E. Grey, I.R. Harrowfield, and K. Mason: Miner. Mag., 1983, vol. 47, pp. 201–08.CrossRefGoogle Scholar
  22. 22.
    C. Klein and A. Philpotts: Earth Materials, 1st ed., Cambridge University Press, New York, NY, 2013.Google Scholar
  23. 23.
    J.S.J. Van Deventer and P.R. Visser: Thermochim. Acta, 1987, vol. 111, pp. 89–102.CrossRefGoogle Scholar
  24. 24.
    J.-W. Kim, Y.-D. Lee, and H.-G. Lee: ISIJ Int., 2001, vol. 41, pp. 116–23.CrossRefGoogle Scholar
  25. 25.
    M. Tripathy, S. Ranganathan, and S.P. Mehrotra: Miner. Process. Extract. Metall., 2012, vol. 121, pp. 147–55.CrossRefGoogle Scholar
  26. 26.
    A. Basumallick: ISIJ Int., 1995, vol. 5, pp. 1050–53.CrossRefGoogle Scholar
  27. 27.
    D.W. McKee and D. Chatterji: Carbon, 1975, vol. 13, pp. 381–90.CrossRefGoogle Scholar
  28. 28.
    R.P.T. Tomkins and N.P. Bansal: Gases in Molten Salts, International Union of Pure and Applied Chemistry, vol. 45/46.Google Scholar
  29. 29.
    A. Lahiri and A. Jha: Metall. Mater. Trans. B, 2007, vol. 38B, pp. 939–48.CrossRefGoogle Scholar
  30. 30.
    N.J. Welham: Miner. Eng., 1996, vol. 9, pp. 1189–1200.CrossRefGoogle Scholar

Copyright information

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

Authors and Affiliations

  1. 1.Metal Extraction and Recycling DivisionCSIR-National Metallurgical LaboratoryJamshedpurIndia

Personalised recommendations