Vitrinite Maceral Separation Using Column Flotation

ABSTRACT

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.

KEYWORDS:

• Coal
• column flotation
• vitrinite maceral separation
• surface characterization

Acknowledgment

Authors are thankful to Dr. Sanjay Chandra, Chief R&D and SS, and Dr. P. K. Banerjee, Chief Raw Materials Group for their support and valuable suggestions during this research work.