综放工作面煤岩近红外光谱特征和机理

Near-infrared spectrum characteristics and mechanism of coal and rock in mechanized caving face

  • 摘要: 为研究综放工作面不同赋存位置的煤与岩石近红外光谱曲线特征和吸收机理,从同煤集团塔山矿综放工作面采集煤与岩石钻芯,按赋存位置的差异将煤与岩石钻芯依次分为:3~5号煤层夹矸、2号煤层夹矸、直接顶岩、基本顶岩、3~5号煤层所含煤,2号煤层所含煤,共计六大类、27种煤与岩石试样。在实验室利用AVANTES近红外光谱仪分别获取27种煤与岩石试样在长波近红外波段(1 100~2 500 nm)的反射光谱曲线。通过X射线衍射、X射线荧光、工业分析等实验手段分别测定煤与岩石试样的矿物成分、元素含量、工业成分含量。同时为研究煤与岩石光谱曲线特征差异的普适性,依次采集山西、山东、宁夏、内蒙古等矿区的22种煤与岩石试样,并分别获取其在长波近红外波段(1 100~2 500 nm)的反射光谱曲线。通过对塔山矿综放工作面煤与岩石试样的光谱特征和吸收机理以及不同矿区煤与岩石试样的光谱特征研究表明:① 煤层夹矸与顶板岩相比,煤层夹矸的吸收特征和曲线斜率绝对值偏小,主要是因为煤层夹矸中相对较多的不透明炭质物质遮蔽了无机离子在其特征波长处的吸收特征。虽然煤中基质(主要是C,H,O元素组成的有机物)是其矿物的5.3倍,但是有机基团在近红外波段没有明显的吸收特征,且大量不透明炭质物质遮蔽了无机离子在近红外波段的吸收特征,使得煤的光谱曲线较为平滑且呈上升趋势。② 煤与岩石光谱曲线的差异特征可用吸收谷深度之和、斜率和凹凸度来描述。

     

    Abstract: In order to study the characteristics and absorption mechanism of near-infrared spectra of coal and rock at different occurrence positions in a fully mechanized caving face,the coal and rock drill cores are collected from the fully mechanized caving face of Tashan mine,including gangue in No. 3-5 coal seam,gangue in No. 2 coal seam,rock of immediate roof,rock of main roof,coal in No. 3-5 coal seam,and coal in No. 2 coal seam. According to the difference of occurrence position,the coal and rock drill cores are divided into a total of 6 categories and 27 types of coal and rock samples. In the laboratory,AVANTES near-infrared spectrometer is used to obtain the reflectance spectra curves of 27 kinds of coal and rock samples at long wave near-infrared band (1 100-2 500 nm). Through X-ray diffraction,X-ray fluorescence and industrial analysis,the mineral composition,element content and in-dustrial composition content of coal and rock samples are determined respectively. Meanwhile,in order to study the universality of the characteristic differences between coal and rock spectral curves,22 coal and rock samples from Shanxi,Shandong,Ningxia,Inner Mongolia and other mining areas are collected in turn,and their reflection spectral curves in the long wave near-infrared band (1 100-2 500 nm) are obtained respectively. The study on the spectral characteristics and absorption mechanism of coal and rock samples in the fully mechanized caving face of Tashan mine and the spectral characteristics of coal and rock samples in different mining areas shows that:① Compared with the roof slate,the absolute value of the absorption characteristics and the slope of the curve of the coal seam sandwich are smaller,mainly because the relatively large amount of opaque carbonaceous materials in the coal seam contain the absorption characteristics of inorganic ions at their characteristic wavelengths. Although the groundmass ( mainly the organic compounds composed of C,H and O elements) in coal is 5. 3 times higher than the mineral,there is no obvious absorption characteristic of organic groups in the near-infrared band,and a large number of opaque carbonaceous substances obscure the absorption characteristic of inorganic ions in the near-infrared band,making the spectral curve of the coal relatively smooth and showing an upward trend. ② The difference between coal and rock spectral curves can be described by the sum of the absorption valley depth,slope and roughness. The study on the spectral characteristics and absorption mechanism of coal and rock in a fully mechanized caving face and the spectral characteristics of coal and rock in different mining areas is to provide a reference and basis for coal and rock identification in the coal mining process.

     

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