THERMOGRAVIMETRIC METHODS FOR DETERMINING CARBON CONTENT IN FLY ASHES

Unburnt carbon content in fly ashes was determined using thermogravime try. After being heated in an inert atmosphere, carbon reacts towards iron oxide components in fly ash, and after it is heated in an oxidizi ng environment, carbon oxidation process overlaps carbonate decomposit ion. A thermogravimetric method combining inert and oxidizing atmosphe res was designed, in such a way that hydrated lime, calcium carbonate, and unburnt carbon contents for several fly ashes were determined. Ca rbon content in fly ash-sized fractions also was determined, with high est carbon content found in the coarsest fractions. (C) 1998 Elsevier Science Ltd.