In this paper,an experimental study

In this paper,an experimental study was conducted in order to test the feasibility of sintering mullite directly from the high-alumina fly ash,without adding any extra material.The results show that the mullite contents in most sintered samples are over 70%.The samples sintered from the beneficiated fly ash have a higher content of mullite than those from the as-received fly ash under the same synthetic conditions.To obtain an equal amount of mullite,a higher sintering temperature is needed for the beneficiated fly ash than for the as-received fly ash.Considering the physical properties of sintered mullite,the favorable sintering temperature is 1400℃for the as-received fly ash and 1500℃for the beneficiated fly ash.A higher sintering temperature and a shorter holding time are profitable to sintering mullite.The orthogonal test confirmed that the dominant factor affecting mullite synthesis is sintering temperature,and that the most profitable matching conditions are 200 MPa-1500℃-3 h for the as-received fly ash and 200 MPa-1500℃-4 h for the beneficiated fly ash.