A huge amount of coal gangue is piled in Beijing

especially in Fangshan District.The best method to utilize it is the transformation of them for producing cement.Because Fangshan gangue is a kind of sandy one

whose mineralogical composition contains clay minerals such as kaolinite

muscovite and chlorite

quartz

calciclase and carbon

etc

it is difficult to improve its activity. In order to explore a way of utilizing it

in this paper

XRD analysis and DSCTG analysis were used to research the activation mechanism of the gangue.Some major factors affecting the thermal activation of the gangue

such as temperature

cooling way and content of the alteration agent

were investigated

strength test of cement mortar and SEM were employed.The results showed that

the strength of cementitious materials obtained by the thermal activation of coal gangue was significantly improved.The activity of Fangshan gangue could be obviously increased when the mixture of powder and bulk gangues were heated to 800℃ for 5 h.The surface of quartz and feldspar crystals was eroded and their chemical bond was broken by adding alteration agent. Fangshan gangue could be highly activated with proper amount of alteration agent during the thermal activation process

so that it could be used as hydraulic binders.