热变煤的变质演化纳米特性及其类石墨结构特征  

Nano properties of metamorphic evolution of thermally altered coaland its graphite-like structural characteristics

作　　者：王绍清[1] 陈昊 王小令 WANG Shaoqing;CHEN Hao;WANG Xiaoling(College of Geoscience&Surveying Engineering,China University of Mining&Technology-Beijing,Beijing 100083)

机构地区：[1]中国矿业大学(北京)地球科学与测绘工程学院,北京100083

出　　处：《煤炭学报》2023年第2期846-854,共9页Journal of China Coal Society

基　　金：国家自然科学基金面上资助项目(42072196)。

摘　　要：热变煤所处地质条件明显异于正常变质作用煤,由于受到直接接触的岩浆侵入体影响,热变煤一方面经受了快速升温缓慢冷却的受热过程,另一方面也受到侵入体接触挤压带来的额外应力作用,这使得热变煤的碳纳米结构变化明显异于正常变质作用煤。为揭示热变煤中碳纳米结构的特殊性,基于X射线衍射(XRD)与高分辨率透射电镜(HRTEM)分析手段,研究热变煤的微晶结构参数演化,同时对热变煤中碳纳米结构类型及其成因进行系统分析。结果表明:与深成变质作用煤相比,热变煤的微晶层间距更接近石墨微晶。在镜质体反射率小于10%时,热变煤的层间距和L_(a)/L_(c)均呈现三阶段变化。在热变煤中,识别出4种碳纳米结构,即无序芳香簇结构、芳香同心环状结构、涡层结构和类石墨状结构。其中,类石墨状结构主要出现在颗粒边缘、显微组分相互挤压面上以及孔隙裂隙边缘处,其成因与颗粒内部应力有关。相比于其他3种碳纳米结构,类石墨状结构的定向性更好,同时其芳香层片的长度也更长。与正常变质煤受热形成的类石墨结构不同,热变煤颗粒边缘类石墨结构的层间距更小而延展度更大。基于此,通过改进的Hummers法可从热变煤中制备得到石墨烯,但缺陷特征明显,因此亟需进一步深入研究。The geological conditions of thermally altered coal are obviously different from those of normal metamorphic coal.Due to the influence of direct contacted intrusion,the thermally altered coal has undergone a process with rapid heating and slow cooling,on the other hand,it is also affected by additional stress caused by the contact extrusion of the intrusion,which also makes the thermally altered coal significantly different from the normal metamorphic coal in terms of carbon nanostructure changes.In order to reveal the particularity of carbon nanostructures in the thermally altered coals,the carbon nanostructures in the thermally altered coals were systematically analyzed based on the previous studies by our research group and other researchers.The evolution of microcrystalline structure parameters for the thermally altered coal was studied,and the types and its genesis of carbon nanostructures in the thermally altered coal were analyzed with the XRD and HRTEM methods.The results show that compared with the metamorphic coal,the interlayer spacing of the thermally altered coal is closer to that of the graphite crystallites.When the vitrinite reflectance is less than 10%,the interlayer spacing and L_(a)/L_(c)of the thermally altered coal show three-stage changes.In addition,four carbon nanostructures were identified in the thermally altered coal,including disordered aromatic cluster structure,aromatic concentric ring structure,turbostratic carbon structure,and graphitic-like structure.Among them,the graphitic-like structures in the thermally altered coal mainly appear at the edges of particles,on the extruded surfaces of micro-components,and at the edges of pores and fissures,which is related to the internal stress of the particles.Compared with the other three carbon nanostructures,the graphite-like structures have better orientation and longer lattice fringe length.Different from the graphite-like structure formed by the heating of normal metamorphic coal,the graphite-like structure at the edge of thermally alter

关 键 词：热变煤 纳米结构 内部应力 结构演化 石墨烯 

分 类 号：TQ536[化学工程—煤化学工程]