The effects of temperature on the phase characteristics and sintering properties of fly ash and red mud between 1050 ℃ to 1200 ℃ had been studied. The results showed that the main mineral phase of fly ash was quartz (SiO2) and mullite(3Al2O3·2SiO2),the major mineral phases of red mud were gehlenite (Ca2Al2SiO7),quartz (SiO2),andradite(Ca3Fe2+3(SiO4)3) and morimotoite (Ca3TiFeSi3O12). Different ratio of fly ash and red mud samples got the relatively lower porosity,the higher bulk density and compressive strength at 1200 ℃. The 5# sample sintered at 1200 ℃ got the porosity of 1.67%,bulk density of 2.10 g·cm-3,compressive strength of 123.23 MPa,achieving sintering dense state,and the dominant phase was (anorthite,sodian) and mullite. The formation of mullite and addition of glass phase in the samples contributed to dense sintering at high temperature.

To provide a basic foundation for the ceramic application of red mud,and take the red mud from a Hejin Aluminum Plant as a case,effects of sintering temperature on the phase transformation and physical properties are studied.The results showed that the main crystalline phases of red mud samples are Gehlenite,Quartz,and a small amount of Albite,Morimotoite and Andradite.When the temperature higher than 1 000 ℃,Quartz,Albite and Morimotoite in sintered samples are gradually reduced,but Gehlenite and Andradite increased with the sintering temperature increased.The proper sintering temperature of red mud was at 1 150 ℃,with the bulk density of red mud samples of 1.82 g/cm3,water absorption of 19.9%,porosity of 36.0% and compressive strength of 58.8 MPa.The increase of Gehlenite and Andradite in red mud at a high temperature and the glass phase played an important role in developing the strength of red mud samples and promoting the ceramic mechanism of red mud.