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.