Beneficiation of an Indian non-coking coal by column flotation

N Vasumathi,S Subba Rao,G Bhaskar Raju,S Prabhakar,S Ratchambigai,T V Vijaya Kumar

doi:10.1007/s40789-016-0129-y

N Vasumathi, S Subba Rao + Show 4 more

Open Access

https://doi.org/10.1007/s40789-016-0129-y

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Abstract

Beneficiation of non-coking coal is gaining ground in India. It not only reduces the volume of inert content to be transported 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 non-coking coal sample of vitrinite type from India was ground to 44 µm (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.

Highlights

Coal, accounting for 63 % of the world’s total energy content, is the world’s most abundant fossil fuel resource
Beneficiation of non-coking coal is gaining ground in India. It reduces the volume of inert content to be transported to the power plant and 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 %
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

Summary

Introduction

Coal, accounting for 63 % of the world’s total energy content, is the world’s most abundant fossil fuel resource. The world supply of crude oil and natural gas is limited and, at projected rate of exploitation is expected to be depleted within the two or three decades. If worldwide economic development is to continue, alternate fuel resources (such as coal) need to be more fully exploited to meet the anticipated world energy requirement. India is in the threshold of techno-economic washing of coal. Large scale beneficiation was resorted to coking coals only for steel making purposes. The stage is set to attract investors to take up beneficiation of non-coking coals for power plants

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