Cleaning of Coal by Multi Gravity Separator

Abstract

India being one of the leading coal consumer, is striving hard to improve the quality of coal supplied to steel and power sectors. In the last 10 years, there has been hardly any improvement in designing of new process technology to beneficiate inferior quality coals. Owing to the stringent quality specification requirements of the end user industry, utilization of lower grade coals through effective beneficiation techniques has become the need of the day. Under these circumstances, multi gravity separator, can augment some solution through beneficiation of ultrafine size (below − 75 µm) coal fines. The present paper outlines an approach made for identifying the utility of MGS for treating coal fines below − 75 µm. A series of 15 tests were conducted by varying three operational variables such as Drum Inclination, Drum speed and its shake frequency following the Box–Behnken design. Effect of these parameters on yield percent, ash percent and recovery of combustibles to clean product, were estimated for each of the experiments. From the results obtained and with the help of RSM approach, levels of operational parameter were optimized to achieve the highest yield of 74.59%, with a combustibles recovery of 84.56% and the lowest ash content obtained was 19.22% from a coal of feed ash 33.5%.