High Ash Non Coking Coal preparation by Tribo-Electrostatic Technique

Tribo-electrostatic method is applied to beneficiate non-coking Indian thermal coal from Ramagundam coal mines containing nearly 45% ash content. The microscopic studies revealed that quartz and kaolinite are the dominant mine-rals whereas illite, goethite, siderite and pyrite are the minor inclusions in the coal. Contact electrification of ash forming minerals and coal matter has been carried out using different tribo-charger materials of Al, Cu, brass, perspex and teflon. The Cu tribo-charger found to be opti-mum to acquire differential charge between ash-forming inorganics and coal matter. The temperature effect on the magnitude of contact charge acquisition found to be sign-ificant. Tests on a laboratory in-house built triboelectro-static free-fall separator with minus 300 microns size fraction of coal showed that the ash content can be reduc-ed from 45% to about 18% and it is feasible to obtain a clean coal as judged by the washability studies. The results illustrate that the non-coking coals can be bene-ficiated using the scientific knowledge on the response and behaviour of coal and noncoal matters to electric charges.