不同变质程度煤中镜质组的元素分布特征:基于Raman和原位微区XRF分析

Distribution of elements in vitrinite of coals with different metamorphic degrees:Based on the Raman andμ-XRF analyses

为明确煤中元素与有机质之间的关系,本文选择山西太原西山煤田6个矿区石炭系—二叠系太原组8号煤层煤样(镜质体最大反射率为1.26%~2.03%)为研究对象,挑选其中的镜煤条带,利用激光共聚焦拉曼光谱仪(Raman)选出镜质组,结合微区X射线荧光光谱仪(μ-XRF)对镜质组中元素含量和分布特征进行分析,试图探讨不同变质程度煤中镜质组的拉曼光谱和元素的耦合关系。研究发现,镜质组中仍然存在着大量的纳米级矿物,在实验操作过程中即使Raman光谱的结果限定了有机组分,但是由于束斑大小的差异,μ-XRF测试时不可避免的受到了煤中纳米级矿物的影响;Al、Si、K、Ti、V、Fe、Co、Ca主要赋存于镜质组中的纳米级矿物中,Ni、Zn、Ga、Ge、Br、S则主要以有机结合态的形式存在。

This study presents a detailed investigation into the relationship between elemental distribution and macerals in coal.Six coal samples,exhibiting a range of vitrinite reflectances(1.26%~2.03%),were collected from the Malan,Xiqu,Tunlan,Dongqu,Ximing,and Duerping coal mines in Xishan coalfield,Taiyuan.A laser confocal micro-Raman spectrometer(Raman)was used to precisely locate vitrinite in the samples.Subsequently,microscopic X-ray florescence spectrometry was applied to analyze the correlation between elemental distribution and Raman spectroscopic characteristics.The results show the presence of numerous nano-size minerals within vitrinite.These minerals significantly influence the distribution of elements in vitrinite,despite the use of Raman spectroscopy for precise vitrinite localization.Elements such as Al,Si,K,Ti,V,Fe,Co,and Ca mainly occurred in these nano-size minerals.Conversely,Ni,Zn,Ga,Ge,Br,and S exhibited a strong affinity for the vitrinite itself.