Effect of maceral composition on the extraction of bituminous coals with carbon disulphide- N-methyl-2-pyrrolidinone mixed solvent at room temperature

Abstract

The residues obtained from the extraction with carbon disulphide- N-methyl-2-pyrrolidinone mixed solvent at room temperature were optically examined and their maceral composition was determined. At low extraction yields, below 30 wt% (daf), a significant amount of semifusinite and pseudovitrinite were extracted. The solvents penetrated the vitrinite particles, softening and extracting them. Pseudovitrinite, an intermediate component between vitrinite and semifusinite, was fragmented like the vitrinite by the penetration of the solvents. Semifusinite was also fragmented and extracted. Fusinite, macrinite, and micrinite were hardly extracted with the mixed solvent. Above 50 wt% (daf) extraction yield, vitrinite was preferentially extracted, but even at 74.1 wt% (daf) extraction yield, some vitrinite components remained in the residue.