The molten behavior of solid products from pulverized coal burning inside the funace is a significant factor

which characterizes the tendency of fouling and slagging inside the boiler

the molten behavior variation of ash samples taken from typical locations in two boilers of Liaohe and Xinwen Power Plant respectively has been analysed and compared. A thorough study has been carried out from the view points of chemical composition in the ash and mineral phase affecting the ash fusion temperature

a reasonable explanation of reversed change tendency occurred in two said boilers being made. Results show that the behavior of coal proper is the essential factor for determining the behavior of mineral substances inside the furnace

and the main difference between coals burned in two said boilers being the existence mode of iron. The principal ironbearing mineral of coal burned in Liaohe Power Plant is pyrite

while ferruginous clay mineral may be the main existence mode of iron in coals burned in Xinwen Power Plant.