Extraction of coal and sludge from the Pechora coal basin in an autoclave at elevated temperature and pressure in an organic solvent environment

Ash-free hypercoals have been obtained from coal sludge from the Inta mining and processing plant and coal from the Vorgashorskoye field by dissolving in N-methylpyrrolidone at elevated temperatures and pressures to establish structural features. The yield of extracts is 79 and 68 %, respectively. The analysis of the initial samples and the obtained products is carried out using the methods of elemental analysis, IR spectroscopy and pyrolytic GC/MS. It is shown that the obtained ash-free extracts have a similar chemical structure, despite the different maturity of the initial coals. According to the data of the TGA-DTG analysis, the nature of decomposition of the organic matter of the initial coal and the obtained extracts is shown.