平顶山矿区煤体微观结构的扫描电镜分析

SEM Analysis of Coal Microstructure in Pingdianshan Mining Area

我国煤矿多为高瓦斯低透气性矿井,由于煤层透气性低,瓦斯抽采效果差,治理难度较大。利用扫描电镜分析煤样的微观结构,可以较为直观的观察到煤的微观孔隙、空洞、裂缝(裂隙)的发育、分布情况,连通情况,孔隙结构等,可为有针对性的采取煤体增透措施、治理煤层瓦斯提供依据。通过对十二矿煤样的详细观测,可以看到其表面含有大量长200～3 500μm、宽1～20μm的裂缝结构,此外还有相当数量的截面积为10～20μm2孔隙结构和一定数量直径为100～200μm的孔洞结构。同时,还观察到这些孔、洞、缝之间也具有连通性。总体来看,十二矿煤样的孔隙、裂缝比较发育,缝、洞之间的连通性较好。另外,观察到十二矿煤样含有3种粘土矿物,分别是蒙脱石(不规则片状)、高岭石(六方板状)和伊利石(絮状),这些粘土矿物具有遇水急剧膨胀的特性,这是瓦斯治理过程中应该注意的问题。

China＇s coal mines are mostly low- permeability, high gas mines, and due to low permeability coal, gas extraction and control is difficult. SEM analysis of coal samples microstructure can observed intuitively microscopic coal pores, voids, cracks （fissures） development, distribution, connectivity of the pore structure, can provide the basis for taking improvement coal permeability measueres and coal seam gas control. Through detailed observations in No. 12 Coal Mine, it can be found that the surface contains large amounts of 200 to 3 500 μm long, 1 to 20μm wide cracks in the structure, in addition to a considerable number of crosssectional area for the 10 to 20 μm2 pore diameter of the structure and a certain number of 100 to 200 μm pore structure. It also observed that these holes also had connectedness between joints. Overall, the pores, cracks in No. 12 Coal Mine coal samples are well developed with better connectivity between holes. In addition, this study observed three clay minerals in coal samples, namely montmorillonite （irregular flakes） , kaolinite （hexagonal plates） and illite （floc）, these clay minerals has the characteristics of a rapid expansion with water, which should be noted in gas control process.