Abstract: According to the component characteristics of fly ash produced by a MSW incineration power plant， the effects of different compatibility ratios of single component and two components on the melting temperature of fly ash were analyzed. The results indicated that the addition of SiO2 could significantly reduce the melting temperature of fly ash， especially for every 1% step increased when the adding mass fraction was 0～5%， the reduction of ash melting temperature was about 14～21 ℃. The addition ratio of Al2O3 could decrease the ash melting point of fly ash within 10% ， but it could increase the melting characteristic temperature of the fly ash when the proportion was 10%～25%. Both CaO and MgO could increase the melting characteristic temperature of fly ash， and CaO could have a great effect. Coal ash with high content of acid oxides could obviously promote the melting of fly ash. Under the condition of alkalinity balance， the addition of binary components SiO2-MgO and SiO2-CaO would further reduce the melting temperature， and the melting aid effect of SiO2-MgO was more obvious than SiO2-CaO. On the contrary， the addition of binary components Al2O3-MgO and Al2O3-CaO would significantly increase the melting temperature of fly ash.

Key words: fly ash, composition, melting temperature, compatibility