煤系隐晶质石墨成矿过程中结构和性能变化研究

Graphite is an important raw material to prepare graphene, which has been listed as a strategic resources. The cryptocrystalline graphite in the coal-bearing strata will be developed seriously in the future with graphite in the metamorphic rocks gradually exhausted. Several typical graphite deposits in the coal-bearing strata will be studed through the methods of mineralogy, crystallography, coal petrology, coal chemistry and tectonic geology. The effects of temperature, shear stress and magmatic fluid on the formation and the stucture ordering of graghite will be discussed in this project based on the studies of graphites with different metamorphic degree. The method to calculate the order degree of graphite will be submitted based on the discriminant analysis of order and disorder structure of graphite. According to the molecular dynamatics by computer simulation, The graphite structure and order change model under the coupling effect of temperature and shear stress will be established, and the dynamatic mechanism of graphite structure ordering change will be illuminated. Finally, the application potential of graphite of coal-bearing strata for high-tech field will be evaluated according to studies on the physical and chemical featues of graphite, exfoliated properties and application properites in rubber composite, and the influence mechanism of graphite structure and surface feature change on the application properties will be clarified.

石墨是制备石墨烯的重要原材料，已被我国列为战略性资源。随着区域变质岩型晶质石墨资源的日益枯竭，煤系隐晶质石墨将成为未来的开发重点。本项目拟以我国几个典型地区煤系隐晶质石墨矿床为研究对象，利用矿物学、结晶学、煤岩学、煤化学、构造地质学等学科研究方法和手段，通过对不同变质程度石墨研究，探讨温度、构造剪切应力和岩浆流体对石墨结构变化和有序化的影响及其形成作用机理。通过对石墨结构中有序结构和无序结构判别分析，提出煤系隐晶质石墨结构有序度评价方法。利用计算机模拟，通过分子动力学方法，建立温度-剪切应力耦合作用下石墨结构及其有序度变化模型，阐明石墨结构有序化动力学机制。通过对不同变质程度石墨理化性能、剥离性能和在橡胶中的应用性能研究，阐明石墨结构和表面性质变化对其应用性能的影响机理，评价煤系隐晶质石墨在高新技术领域的应用潜力。

煤系石墨是一种重要的非金属矿产资源。本项目以我国湖南新化、湖南鲁塘、吉林磐石和陕西凤县等地不同石墨化程度的煤系石墨为研究对象，对煤向石墨转变过程的控矿因素、煤大分子结构有序化过程、石墨结构变化对其应用性能影响进行研究。认为煤只有在受岩浆热作用的同时伴随侧向挤压带来的应变能破坏煤中的纳米级孔结构，才能使煤大分子结构中的石墨微晶定向排列联结形成石墨，煤系石墨的形成温度为500~550 ℃，发现了铁等过渡金属元素对石墨的形成具有催化作用的证据。在煤系石墨中首次报道了针状石墨和细鳞片石墨，发现煤系石墨反射率偏低而不能作为其变质程度标志。提出了煤向石墨演化不同阶段划分参数。基于反应力场(ReaxFF)的分子动力学模拟，从分子尺度可视化了无烟煤石墨化过程中芳香碳层拼叠及有序化的演化过程和主控因素。煤系石墨的结构有序化度对其理化性能和应用性能具有重要影响，发现随着石墨化度的提高，煤系石墨的电阻率逐渐降低、热导率逐渐升高、制备出的氧化石墨烯和还原石墨烯的产率也逐渐提高。利用煤系石墨采用绿色还原方法成功制备出石墨烯，大大拓展石墨烯原料的来源范围，为未来煤系石墨的高附加值利用探索出新方向。