An article written by T. Muangthong-on, J. Wannapeera, H. Ohgaki, K. Miura was published in Energy Fuels.
Title; Effect of Solvent on the Degradative Solvent Extraction of Low Rank Coal
DOI: 10.1021/acs.energyfuels.7b02352
Advanced Energy Generation Division　Quantum Radiation Energy Research Section

Carbon fiber can be prepared from the small molecular-weight fraction recovered, Soluble
The Residue is a high quality solid fuels with small propensity to spontaneous heating