Acid demineralization effect on the sonication-assisted solvent extraction of vitrinite coal of the Powder River Basin

Abstract

Solvent-extraction of economic low-grade coals has gained recent interest as a way to produce new feedstocks for the synthesis of advanced carbon materials including polymers. Herein, we report the effect of coal demineralization by hydrochloric acid treatment on the sonication-assisted extraction of subbituminous coal from the Powder River Basin in Wyoming, USA at room temperature and the analysis of the initial and residual coals by FT-IR and solid-state 13C NMR. The applied demineralization reduced ash content from 9.9% to 7% without any notable change in the coal composition or structure. Despite leaving the mineral matter in the coal, the demineralization significantly increased the extraction yield for all applied solvents, for ethylenediamine from 8.1% to 15.2%, for pyridine from 4.9% to 12.4%, and acetone from 1.1% to 4.5%.