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首页> 外文期刊>Applied clay science >Influence of iron on kaolin whiteness: An electron paramagnetic resonance study
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Influence of iron on kaolin whiteness: An electron paramagnetic resonance study

机译：铁对高岭土白度的影响：电子顺磁共振研究

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摘要

Well characterized kaolin samples from different deposits of Brazil were studied by electron paramagnetic resonance. Three paramagnetic species attributed to iron in different chemical environments were identified in raw samples. A very intense and broad line with 0.2 mT linewidth was typical of large particles of iron oxides/hydroxides. A species at g=2.0 with 0.04 mT line width was associated with superparamagnetic particles adsorbed to kaolinite surfaces or trapped between its lamellae. An isotropic and/or orthorhombic species in the g=4.2 region belongs to structural Fe~(3+) replacing Al~(3+) in sites with different crystal-field symmetries. It was verified that large iron oxide particles were responsible for keeping the kaolin whiteness at levels below 50%, Superparamagnetic iron particles mainly affect whiteness in the range of 50%< whiteness <86%. They may be totally removed by magnetic separation followed by chemical treatment using sodium dithionite. The kaolin high whiteness levels (whiteness >86%) were determined by Fe~(3+) iron content in the kaolinite structure. However, only a small part of this species can be removed from the kaolinite structure by traditional industrial processing techniques. These results showed that EPR is a powerful technique to assist in controlling kaolin quality in industrial processes.
机译：通过电子顺磁共振研究了来自巴西不同矿床的特征良好的高岭土样品。在原始样品中鉴定出三种在不同化学环境中归因于铁的顺磁性物质。大颗粒的氧化铁/氢氧化物通常具有非常强烈且宽广的线条（线宽为0.2 mT）。 g = 2.0且线宽为0.04 mT的物质与吸附在高岭石表面或夹在其薄片之间的超顺磁性颗粒有关。 g = 4.2区域内的各向同性和/或正交晶物种​​属于结构性Fe〜（3+），取代了具有不同晶体场对称性的位点中的Al〜（3+）。证实了大的氧化铁颗粒导致高岭土白度保持在低于50％的水平。超顺磁性铁颗粒主要影响白度在50％＜白度＜86％的范围内。可以通过磁力分离将其完全去除，然后使用连二亚硫酸钠进行化学处理。高岭土高白度水平（白度> 86％）由高岭石结构中的Fe〜（3+）铁含量确定。但是，通过传统的工业加工技术只能从高岭石结构中除去该物种的一小部分。这些结果表明，EPR是有助于控制工业过程中高岭土质量的强大技术。

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  • 来源
    《Applied clay science》 |2010年第3期|P.170-175|共6页
  • 作者

    Luiz Carlos Bertolino; Alexandra Malta Rossi; Rosa Bernstein Scorzelli; Mauricio Lenardo Torem;

  • 作者单位

    Centre for Mineral Technology, Av. Pedro Calmon, 900, Cidade Universitdria, 21-941-908, Rio de Janeiro, Brazil;

    rnBrazilian Center for Research in Physics, R. Xavier Sigaud 150, 22290-180, Rio de Janeiro, Brazil;

    rnBrazilian Center for Research in Physics, R. Xavier Sigaud 150, 22290-180, Rio de Janeiro, Brazil;

    rnDepartment of Materials Science and Metallurgy, Catholic University of Rio de Janeiro, R. Marques de Sao Vicente, 225,22453-900, Rio de Janeiro, Brazil;

  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);美国《生物学医学文摘》(MEDLINE);
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

    kaolinite; iron; EPR; benenciation; mineralogical characterization;

    机译：高岭石铁;EPR;选美矿物学表征;

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