贵州普安矿区晚二叠世煤中微量元素的质量分数和赋存状态

贵州普安矿区晚二叠世煤中微量元素的质量分数和赋存状态

  • 摘要: 运用电感耦合等离子体质谱(ICP-MS)、X射线荧光光谱(XRF)、冷原子吸收光谱(CV-AAS)、原子荧光光谱(AFS)、离子选择性电极法(ISF)、带能谱仪的扫描电镜(SEMEDX)和逐级化学提取技术(SCET)对贵州普安矿区晚二叠世煤中微量元素的质量分数、赋存状态和成因机理进行了研究。结果表明,贵州普安矿区2号主采煤层的矿物组成主要为低温热液流体成因的黄铁矿和陆源碎屑成因的黏土矿物;与贵州煤、中国大部分煤和美国煤相比,该煤中As (36.9×10-6)、Cd (10.2×10-6)、 Cr (167.3×10-6)、Cu (365.4×10-6)、Hg (2.82×10-6)、Mo (92.6×10-6)、Ni (82.6×10-6)、Pb (184.6×10-6)、Se(6.23×10-6)、Zn (242.3×10-6)和U (54.6×10-6)显著富集。而另外4个主采煤层(1号、8号、11号和17号煤层)中微量元素的质量分数与贵州煤、中国大部分煤和美国煤中的相当。普安矿区2号煤层中的As、Cd、Hg、Mo、Ni、Pb和Zn等元素主要赋存在黄铁矿中,而Cr、Cu和U主要存在于高岭石中,表明低温热液流体和陆源碎屑对煤中微量元素的富集起了决定作用。

     

    Abstract: Understanding the concentrations and origins of trace elements in coal is both practically and theoretically significant in the utilization of potentially valuable trace metals in coal combustion byproducts and revealing origins of coalformation. The contents, occurrence modes, and origin of trace elements in the Late Permian coals from the Puan Coalfield of western Guizhou Province were studied using inductively coupledplasma mass spectrometry (ICPMS), Xray fluorescence spectrometry (XRF), coldvapor atomic absorption spectrometry (CVAAS), atomic fluorescence spectrometry (AFS), ionselective spectrometry (ISF), scanning electron microscope equipped with dispersive Xray energy (SEMEDX), and sequential chemical extraction technology (SCET). The results show that minerals in the No.2 coal are mainly pyrite of lowtemperature hydrothermal origin and clay minerals of detrital terrigenous origin. The pyrite in the No.2 coal mainly occurs as fracturefillings and clay minerals as lenses and fine particles in collodetrinite. The elements including As 〖WTBZ〗(36.9×10-6), Cd (10.2×10-6), Cr (167.3×10-6), Cu (365.4×10-6), Hg (2.82×10-6), Mo (92.6×10-6), Ni (82.6×10-6), Pb (184.6×10-6), Se (6.23×10-6), Zn (242.3×10-6), and U (54.6×10-6), 〖WTB1〗are significantly enriched in the coal, as compared with those in coals from Guizhou, China, and USA. However, the contents of trace elements in the other 4 coals (No.1, No.3, No.4, and No.5) are close to those in coals from Guizhou, China, and USA. Elements of As, Cd, Hg, Ni, Pb, and Zn in No.2 coal mainly distribute in pyrite, and Cr, Cu and U are mainly in kaolinite, indicating that the lowtemperature hydrothermal fluid and detrital material of terrigenous origin play a critical role in the contents and occurrence modes of trace elements in the No.2 coal.

     

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