Beneficiation and utilization of low volatile coking coal and non-linked washery Indian coking coals for metallurgical purposes

摘要

Indian coal industry is the world's third largest in terms of production and fourth largest in terms of proven coal resources. Coal deposits are of drift origin, high in ash content but low in sulphur. There are 20 major coalfields located in east and south eastern quadrant of the country. The coking coal reserves are less compared to the non coking coals and the good quality coking coals has been exhausted leaving behind poor quality feed stock for the metallurgical sector. For production of Iron & Steel through blast furnace route, coking coal is an important raw material. The good quality coking coals of the upper seams are fast depleting leaving behind the inferior quality lower seam coal. The lower seam coals presently being mined are mostly low volatile coking coal (LVC). They constitute about 50% of the total coking coal reserves in India. These coals are characterized by high raw coal ash content and poor washability characteristics. Beneficiation of the lower seam coals in the existing washery circuits (2 or 3 product) does not yield requisite quality demanded by the steel sector of the country and as a result it is termed as Non-Linked Washery (NLW) coals, and the entire production of inferior coals is diverted to the thermal power sector, thus, wasting the scarce coking coal resources. In this paper, an attempt has been made to focus the cost-effective and eco-friendly approach for utilization of the LVC/NLW coking coals illustrating with a case study.