Beneficiation of an Indian non-coking coal by column flotation

Abstract

Beneficiation of non-coking coal is gaining ground in India. It not only reduces the volume of inert content to betransported to the power plant and also lowers the wear in the boiler houses. For special applications such as the fuel for integrated gasification combined cycle plant (IGCC), the ash content in the coal should preferably be below 15 %. Indian coals are characterized by high inter-grown ash content mainly due to ‘drift origin’ of Gondwana formation in Permian age.This warrants fine grinding of non-coking coal in order to liberate the ash forming minerals from coal macerals. A noncoking coal sample of vitrinite type from India was ground to 44 lm (d80) and subjected to column flotation to improve its quality. The non-coking coal analyzing 34.6 % ash, 26.2 % volatile matter, 1.3 % moisture and 37.9 % fixed carbon could be upgraded to a concentrate/froth of 14.83 % ash at 72.18 % yield by optimizing collector and frother dosages and flotation column operating parameters, namely, froth depth, superficial feed velocity and superficial air velocity. The concentrate produced by this process is suitable as fuel for IGCC in coal-to-electricity route.