LOW-TEMPERATURE ASHING - A METHOD TO ASSESS THE EFFECT OF ADDITIVES ON GRINDING AND FLOTATION OF COAL

In this paper an attempt has been made to study the effect of using ch emical additives on grinding and flotation of thermal coal containing 40% ash. The mill products are analysed by the new technique of low te mperature ashing (LT Ash). The LT ash characterisation are in excellen t agreement with the results of sink float and flotation studies. Trie thanolamine and Polyethylene glycol have shown many fold enhancement i n fine grinding. However, Triethanol amine selectively grinds gangue i n comparison to coal, while Polyethylene glycol enhances selective gri nding of coal in comparison to gangue. This is supplemented by the res ults of flotation. There is an increase in recovery of combustibles fr om 39% in absence of additive, to 83% in Polyethylene glycol grinding. The flotation product contained ash between 22-25%.