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Crushing mechanism plays a vital role in liberation of coal macerals (organic constituents), which aid in coke making. Due to the use of impact mills, vitrinite maceral grains shatter and participation in coke making is reduced. To address this issue, a new crushing machine based on a shear fracture mechanism has been developed and termed as coal shear crusher (CSC). It is shown that by using CSC one can take advantage of the viscoelastic property of vitrinite maceral. When compared to hammer mill, CSC processed coal showed improvement in plastic layer thickness (PLT), crucible swelling number (CSN), rank and coke strength after reaction (CSR) of the coal blends. Coals with vitrinite reflectance (Ro) greater than 1%, when processed using CSC showed greater improvement in coke properties as compared to coals with less than 1% Ro. Coal blend cost reduction can be effectively obtained if CSC technology is used, by increasing the portion of poor coking coal by replacing good coking coals. Present study scopes the utilization of up to 10% of CSC processed component in the coal blend, which is currently limited due to concerns related to coal cake stability which if overcome can increase the fraction of poor-coking coal in blends even further. [ABSTRACT FROM AUTHOR]

The separation of vitrinite is being primarily carried out through density-gradient concentration (DGC) method. However, this technology is limited to laboratory-scale operations, since gravity plays a trivial role in the separation of ultrafine particles. In the present investigation, processing of vitrinite macerals on a large scale was explored using column flotation. Two coal samples (medium coking and non-coking) of less than 500 µm size were processed at neutral pH in single-stage column operation. Column-flotation operating parameters such as air flow rate, collector, and frother dosage were optimized to obtain the maximum recovery of vitrinite maceral. Enrichment of vitrinite in flotation products was confirmed through petrography studies with respect to feed. The column-flotation results were compared against to theoretical value obtained from sink-and-float analysis. The extent of vitrinite enrichment using flotation column was further investigated through surface-characterization techniques such as contact angle, zeta potential, and Fourier transform-infrared spectroscopy. The column-flotation results showed that the maximum yield was 67% and 77.5% for Coals A and B and the corresponding recovery was 84% and 93%, respectively. [ABSTRACT FROM AUTHOR]