湖南鲁塘煤系隐晶质石墨矿物学特征

Mineralogical Characteristics of Coal-based Cryptocrystalline Graphite in Lutang Area,Hunan Province,China

综合运用多学科技术手段对鲁塘煤系隐晶质石墨进行研究,以期探索煤系石墨的矿物学特征随变质程度的变化规律。通过系统采样的方法,选取不同变质程度的鲁塘煤系石墨样品为研究对象,运用X射线荧光光谱法(XRF)、X射线衍射法(XRD)、扫描电镜(SEM)、激光拉曼光谱法、热重法等技术手段,对石墨的化学成分、矿物组成、晶体结构、热学性质进行了研究。结果表明,鲁塘煤系石墨主要由隐晶质石墨和少量石英、方解石、白云母、绿泥石、高岭石组成,固定碳含量为41.95%~88.43%,石墨主要呈细小的不规则鳞片状,其晶体形态随着变质程度的增高而逐渐完善。石墨化程度较高,为88.37%~98.84%,3R多型变体含量为9.45%~14.56%,石墨的氧化起始温度较低,在530℃左右,隐晶质石墨的氧化起始温度和终止温度均低于显晶质石墨。煤系石墨的石墨化程度、结晶程度、氧化起始温度与变质程度呈正相关关系,3R多型变体含量与变质程度呈负相关关系。

This paper studies the coal-based cryptocrystalline graphite in Lutang area,Hunan Province,China by using multidisciplinary techniques to explore the changing rules of the mineralogical characteristics of coal-based graphite with the variation of metamorphism degree. Through the method of system sampling,we selected coal-based graphite samples from Lutang with different degrees of metamorphism as our research objects. The chemical composition,mineral composition, crystal structure and thermal properties of graphite were studied by X-ray fluorescence spectroscopy( XRF),X-ray diffraction( XRD),scanning electron microscopy( SEM),laser Raman spectroscopy,thermogravimetry and other technical means. Results show that the graphite is mainly composed of cryptocrystalline graphite and a small amount of quartz,calcite,muscovite,chlorite and kaolinite,and the fixed carbon content is 41. 95% ~ 88. 43% . Graphite is mainly small and irregular scales,and its crystal form gradually improves with increasing degree of metamorphism. The degree of graphitization is high,and the value is 88. 37% ~98. 84% . The content of 3 R multi-variant is 9. 45% ~ 14. 56% . The initial oxidation temperature of graphite is lower,at about 530 ℃. The initial temperature and the termination temperature of the crytocrystallina graphite are lower than that of the crystalline graphite. There are positive correlations for the degree of graphitization with the degree of crystallization,the initial temperature of oxidation and the degree of metamorphism of graphite,and there is a negative correlation between the content of 3 R multi-variant and the degree of metamorphism.