Project on Reduction of Ash in difficult-to-float non coking Indian coal

Abstract

INDIA is the third largest coal producer in the world and represented about 9-10% of the total world coal reserves. The present geologically known reserves of coals in India are of the order of 267 billion tones. Indicated in-situ reserve of Gondwana coal is over 100 billion tonnes upto 1200 metre depth. Indian coals are genera-lly contains higher amounts of integrated dirt and norma-lly difficult to wash. Consequently controlled crushing of these coals became necessary for better liberation of dirt before the coals are upgraded by washing. The need to crush coal to smaller sizes flotation and -0.063 for better liberation of dirt for its subsequent removal by washing creates the problem of generation of more coal fines. Added to this the adoption of mechanization in mining has also increased the quantum of fines generation in the recent past. Fine coal treatment and disposal of washery tailings are now creating alarming problems to global environment. In India, the Central coal washeries with their present bene-ficiation circuits are producing about 1.6 Mt of coking coal fines per annum. These slurries are not processed further in most of the washeries because of so many reasons. Froth Flotation is a commercially established process for beneficiation of coal fines and it is incor-porated in most of the coking Coal Preparation Plants in India.