Optimization for the COD reduction and thermodynamics research of coal-series kaolin

  • Teng HuangEmail author
  • Shaomin Lei
  • Yuanyuan Liu
  • Bo Li
Original Article


Coal-series kaolin is the product of seam deposition in coal-accumulating basin, and may always contain reducing substances. The reducing substances such as carbon matter and pyrite could cause relatively high chemical oxygen demand (COD) of the raw kaolin, resulting in low quality kaolin products. In this study, narrow range classification and calcination were investigated to evaluate decreasing COD on coal-series kaolin from the Hubei Province. The kaolin and roasting products were characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF) and thermogravimetry–differential scanning calorimetry (TG-DSC) analyses. The results showed that the COD value in kaolin ore (19,252 µg/g) was largely concentrated in the size fraction of – 150 to + 60 μm. The optimum conditions for reducing COD were identified to be – 74 to + 60 μm at a roasting temperature of 450 °C, and the COD value decreased from 27517 to 585 µg g−1. Moreover, the COD value and Ea showed linear correlation (R2 = 0.932) among different particle sizes, and G(α) = \( \left[ {1 - \left( {1 - \alpha } \right)^{{\frac{1}{2}}} } \right]^{{\frac{1}{2}}} \) could be regarded as the most possible mechanism function for the thermal decomposition of coal-series kaolin.


Coal-series kaolin Decreasing COD Thermodynamics Activation energy 



This work was financially supported by Academician workstation of Yichang Huilong Science and Technology Co., Ltd. Association of Science and Technology of Hubei Province[2013]104-22. Thanks to Mineral Processing “211” Key Laboratory of Wuhan University of Technology and Foundation 17zx7140 of Southwest University of Science and Technology.


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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  1. 1.Key Laboratory of Solid Waste Treatment and Resource Recycle Ministry of EducationSouthwest University of Science and TechnologyMianyangChina
  2. 2.School of Resource and Environment EngineeringWuhan University of TechnologyWuhanChina
  3. 3.Yichang Huilong Science and Technology Co., LtdYichangChina

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