Coal microscopy as a tool to understand the beneficiation problems of Indian Gondwana coals

Abstract

The present paper intends to demonstrate the occurrence of mineral matter as a deterrent in coal beneficiation as evidenced through coal microscopy. The Indian Gondwana coals are known for their high ash content due to the presence of inorganic mineral matter occurring in high concentration. These minerals have been found to occur as ‘deep intergrowth’, ‘massive impregnation’, ‘superficial mounting’, ‘filling and depletion of micropores’’, ‘mechanical cavity filling’, and ‘fusinitic cavity filling’. It is difficult to liberate these mineral matter from coal, creating problems during their beneficiation. The conventional techniques which are being followed for the beneficiation of coal in India include hand picking, sizing, blending, pulverizing, washing, dry cleaning, dedusting, dewatering, drying and briquetting and they are not instrumental so far. Therefore, some non-conventional means of coal beneficiation involving microbial treatment or protein enzyme technology may be tried for Indian coals