Preparation of coal-based graphite with different microstructures by adjusting the content of ash and volatile matter in raw coal

ABSTRACT

The microstructure of a material determines its macroscopic properties. In this study, coal with varying degrees of metamorphism was selected as raw materials. High-temperature graphitization was carried out under the same heat treatment conditions following different pretreatment. The coal-based graphite with different microstructure (polycrystalline graphite, monocrystalline graphite, spherical graphite, honeycomb graphite, and rod-like graphite) were obtained. The results show that the graphitization effect of high-rank coal is better than that of low-rank coal but the graphitization degree of products can be greatly improved after pretreated by pickling. Their resistivity is the same order of magnitude as that of natural graphite, and they all have porous structures with large specific surface areas. They are not only good semeconductor materials but also have potential applications in other fields based on their interesting microstructrues.

KEYWORDS:

• Graphitization
• coal-based graphite
• microstructure
• polycrystalline
• monocrystalline

Highlights

1. The coal-based graphite materials with different microstructures were obtained.

2. The average lateral sizes (La) of coal-based graphite crystallite is positively proportional to the ash content of raw coal.

3. The graphitization degree of products can be greatly improved after pretreated by pickling.

Acknowledgments

The authors would like to thank ShenHua Ningxia Coal Industry Group for financial support and providing Taixi anthracite samples. We also want to thank the support of Advanced Analysis & Computation Center of China University of Mining and Technology.

Additional information

Funding

This work was supported by the National “Twelfth Five-Year” Plan for Science & Technology [2014BAB01B02].