Effects of Oxalic and L-ascorbic acids on Iron Removal form Iron-bearing Illite

일라이트 분체 내에 함유된 산화철 제거에 옥살산과 L-아스코르브산이 미치는 영향

  • Lee, Won-Pyo (Department of Earth System Sciences, Yonsei University) ;
  • Kang, Il-Mo (Department of Earth System Sciences, Yonsei University) ;
  • Moon, Hi-Soo (Department of Earth System Sciences, Yonsei University)
  • 이원표 (연세대학교 지구시스템과학과) ;
  • 강일모 (연세대학교 지구시스템과학과) ;
  • 문희수 (연세대학교 지구시스템과학과)
  • Published : 2007.04.28


This study was focused on iron removal from illite by L-ascorbic and oxalic acids. Iron has been shown as a secondary mineral such as iron oxides and hydroxides in illite ores. It is also known as a primary agent to degrade brightness index of the ores. Methods such as physical separation and chemical leaching with strong inorganic acids have been widely used to remove the iron from the ores. However, these methods are expensive and give rise to environmental problems. In this study, we examined an alternative method using solutions with different set of combination of sulfuric, hydrochloric, L-ascorbic, and oxalic acids. Compared to chemical treatments with only inorganic acids, our results demonstrate that an addition of L-ascorbic acid in inorganic acids results in decreasing both total concentrations of the inorganic acids and time for the treatments. The treatment with 0.15 M L-ascorbic acid and 0.25 M sulfuric acid in solution for 60 min significantly improved the brightness index from 42.4% to 74.4%. This improvement is similar to that of treatment with only 2.5 M sulfuric acid alone for 150 min. Mineralogical and chemical analyses were performed to compare the effect of acid leaching on illite powders. No obvious differences are observed in the mineralogical characteristics and particle size distributions of the samples. These results suggest that the treatment with the addition of L-ascorbic acid in sulfuric acid could effectively remove iron without modifying the physicochemical properties of illite under conditions used in this study.


  1. Ambikadevi, V.R. and Lalithambida, M. (2000) Effect of organic acids on ferric iron removal from iron-stained kaolinite. Applied Clay Science, 16, 133-145 https://doi.org/10.1016/S0169-1317(99)00038-1
  2. Cameselle, C., Nunez M.J. and Lema, J.M. (1997) Leaching of kaolin iron oxides with organic acids. J. Chem. Tech. Biotechnol, 70, 349-354 https://doi.org/10.1002/(SICI)1097-4660(199712)70:4<349::AID-JCTB791>3.0.CO;2-4
  3. Conley, R.F. and Lloyd, M.K. (1970) Improvement of iron leaching in clays: optimizing processing parameters in sodium dithionite reduction. Ind. Eng. Chem. Process. Des. Deuelop., 9, 595-601 https://doi.org/10.1021/i260036a017
  4. Grim, R.E., Bray, R.H. and Bradley, W.F. (1937) The mica in argillaceous sediments. American Mineralogist, 22, 813-829
  5. Mandal, S.K. and Banerjee, P.C. (2004) Iron leaching from china clay with oxalic acid: effect of different physicochemical parameters. Int. J Miner. Process., 74, 263-270 https://doi.org/10.1016/j.minpro.2004.01.004
  6. Rieder, M., Cavazzini, G., D'yakonov, Y.S., Frank-Kamenetskii, V.A., Gottardi, G., Guggenhem, S., Koval, P.V., Muller, G., Neiva, A.M.R., Radoslovich, E.W., Robert, J.L., Sassi, F.P., Takeda, H., Weiss, Z. and Wanes, D.R. (1998) Nomenclature of the Micas. The Canadian Mineralogist, 36, 41-48
  7. Srodon, J. and Eberl, D.D. (1984) Illite: in Micas, Reviews in Mineralogy, 13, S.W. Bailey, ed., Mineral. Soc. Amer., Washington, D.C., 495-544
  8. Veglio, E, Passariello, B., Toro, L. and Marabini, A.M. (1996) Development of a bleaching process for a kaolin of industrial interest by oxalic, ascorbic, and sulfuric acids: preliminary study using statistical methods of experimental design. Ind. Eng. Chem. Res., 35, 1680-1687 https://doi.org/10.1021/ie950427s
  9. Veglio, F., Passariello, B., Barbaro, M., Plescia, P. and Marabini, A.M. (1998) Drum leaching tests in iron removal from quartz using oxalic and sulphuric acids. Int. J. Miner. Process., 54, 183-200 https://doi.org/10.1016/S0301-7516(98)00014-3