Coal-based graphite has become the main material of emerging industries. The microstructure of coal-based graphite plays an important role in its applications in many fields. In this paper, the effect of carbon disulfide/N-methyl-2-pyrrolidone solvent mixture extraction on the microstructure of bituminous coal-based graphite was systematically studied through preliminary extraction coupled with high-temperature graphitization. The graphitization degree g (75.65%) of the coal residue-based graphite was significantly higher than that of the raw coal-based graphite. The crystallite size La of the coal residue-based graphite was reduced by 47.06% compared with the raw coal-based graphite. The ID/ IG value of the coal residue-based graphite is smaller than that of the raw coal-based graphite. The specific surface area (16.72 m2/ g) and total pore volume (0.0567 m3/ g) of the coal residue-based graphite are increased in varying degrees compared with the raw coal-based graphite. This study found a carbon source that can be used to prepare coal-based graphite with high graphitization degree. The results are expected to provide a theoretical basis for further clean and efficient utilization of the coal residue resources.

    Abstract
    1 Introduction
    2 Materials and experimental
        2.1 Preparation of coal residue
        2.2 Graphitization processes
        2.3 Material characterization
    3 Results and discussion
        3.1 FT-IR
        3.2 XRD
        3.3 Raman
        3.4 SEM
        3.5 BET
    4 Conclusion
    Acknowledgements 
    References

• Lipeng Wang(National Engineering Research Center of Coal Preparation and Purification, China University of Mining and Technology, School of Chemical Engineering and Technology, China University of Mining and Technology)
• Zongxu Yao(National Engineering Research Center of Coal Preparation and Purification, China University of Mining and Technology, School of Chemical Engineering and Technology, China University of Mining and Technology)
• Zhimin Guo(National Engineering Research Center of Coal Preparation and Purification, China University of Mining and Technology, School of Chemical Engineering and Technology, China University of Mining and Technology)
• Xiaofeng Shen(National Engineering Research Center of Coal Preparation and Purification, China University of Mining and Technology, School of Chemical Engineering and Technology, China University of Mining and Technology)
• Zhiang Li(National Engineering Research Center of Coal Preparation and Purification, China University of Mining and Technology, School of Chemical Engineering and Technology, China University of Mining and Technology)
• Zhengqi Zhou(National Engineering Research Center of Coal Preparation and Purification, China University of Mining and Technology, School of Chemical Engineering and Technology, China University of Mining and Technology)
• Yuling Wang(School of Chemical Engineering and Technology, China University of Mining and Technology)
• Jian‑Guo Yang(National Engineering Research Center of Coal Preparation and Purification, China University of Mining and Technology, School of Chemical Engineering and Technology, China University of Mining and Technology)