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

Abstract

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.

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