Molecular structure-driven mechanistic insights into the thermally inert refining processes for anthracite conversion

Background

Anthracite, characterized by its high structural order and carbon content, offers unique potential for fabrication of advanced carbon materials. However, the molecular mechanisms governing its thermally inert refining processes (TIRP) remain unclear, particularly the dynamic evolution of polyaromatic networks and CC/C—X bonds cleavage-reorganization during thermal treatment.

Methods

This study investigates Rujigou anthracite from Ningxia, China through an integrated approach combining material characterization, controlled thermal treatment experiments, and molecular modeling calculations.

Significant Findings

Accurately reproduced the ordered 3D configuration, carbonization behavior, and oriented aromatic stacking of RJG-OM during TIRP at the atomic scale. Integrated micro/macro-scale analysis revealed a three-stage TIRP mechanism: bond cleavage without new fragments below 330 °C; aromatic collapse and carbon rearrangement at 330∼810 °C; volatile release and aromatic expansion dominating skeleton reorganization above 810 °C. Heteroatom removal involved triphase C=O evolution N-6→N-5 conversion. The release of oxygen from C=O primarily occurs through decarboxylation-induced growth, pyrolysis equilibrium, and high-temperature restructuring. The transformation of nitrogen-containing heterocycles from N-6 to N-5 follows a hydrogenation-ring opening-reconstruction pathway, accompanied by a nearly linear increase in N-5 content and a synchronous decrease in N-6/NOx levels.