Formation and kinetics of porous cordierite from fly ash

Porous cordierite ceramics were prepared from a mixture of coal fly ash and basic magnesium carbonate at 1100-1350℃. Porosity,flexural strength and thermal expansion coefficient of the samples sintered at 1300℃ were estimated to be 26%,65 MPa and 4.21×10-6/ ℃ ,respectively. The kinetics of the formation progress was investigated by stepwise isothermal dilatometry (SID) accompanied with XRD,SEM and porosity measurement. It was found that the isothermal shrinkage data from SID could be well analyzed to get kinetic parameters according to the em-pirical rate equation developed by Makipirtti-Meng,dY/dt=nk(T)Y(1-Y)(Y/1-Y)1/n,where Y is the fractional shrinkage during the sintering process and n is a dimensionless component. The apparent activation energy △E values for 900-1000℃ and 1050-1150℃ were 1294 and 1778 kJ/mol,respectively.

Porous cordierite ceramics were prepared from a mixture of coal fly ash and basic magnesium carbonate at 1100-1350℃. Porosity, flexural strength and thermal expansion coefficient of the samples sintered at 1300℃ were estimated to be 26%, 65 MPa and 4.21×10^-6/℃, respectively. The kinetics of the formation progress was investigated by stepwise isothermal dilatometry （SID） accompanied with XRD, SEM and porosity measurement. It was found that the isothermal shrinkage data from SID could be well analyzed to get kinetic parameters according to the erapirical rate equation developed by Makipirtti-Meng, dY/dt=nk（T）Y（1-Y）（Y/1-Y）^（1/n）,where Y is the fractional shrinkage during the sintering process and n is a dimensionless component. The apparent activation energy △E values for 900-1000℃ and 1050-1 150℃ were 1294 and 1778 kJ/mol, respectively.