Recovery of Clean Coal from Washery Rejects by Flotation

Abstract

Attempts have been made to recover the additional clean coal from the rejects generated by the heavy media bath of a coking coal washery in Eastern India. As received rejects sample contains around 18.68 % volatile matter, 43.24 % ash and 38.08 % fixed carbon on dry basis. Beneficiation study by conventional cell flotation has been carried out to examine the possibility of reducing the ash content of the sample. But liberation of clean coal from rejects is required before subjecting to any separation process. The reject coal is ground to different particle size and separated by froth flotation. An attempt has been made to systematically analyse the factors influencing the flotation process using the technique of statistical design of experiments. Studies have been conducted at different operating conditions. It is possible to get clean coal with 19.68 % ash at 32.45 % yield and 45.57 % combustible recovery from the reject coal with 43.24 % ash.