In the present study, coal fly ash was used as the main starting material (80.74 wt.%) in the production of the cordierite-based ceramics by benefiting from its high contents of silica… Click to show full abstract
In the present study, coal fly ash was used as the main starting material (80.74 wt.%) in the production of the cordierite-based ceramics by benefiting from its high contents of silica and alumina. The phase evolutions and the properties of sintered materials in the range of 900–1200 °C were investigated by thermogravimetric and differential thermal analyses (TG-DTA), X-ray diffraction (XRD), Fourier transform infrared (FTIR), scanning electron microscopy (SEM), compressive strength, bulk density, and apparent porosity. The results revealed that the increase in firing temperature from 900 °C to 1200 °C induced the transformation of coal fly ash components and the magnesium oxide into cordierite with high purity. The formation of the cordierite at 1200 °C involved the densification of the ceramic body and the decrease in the apparent porosity to 22%. The compressive strength was improved with the increase in sintering temperature and reached a maximum of 128 MPa. The obtained cordierite-based ceramics exhibited a thermal conductivity of 1.12 W/m.K, along with high mechanical properties, which promoted its applications for thermal insulators. Also, the dielectric constant (ε = 9.5 at 1 MHz) measurements indicated that the cordierite-based ceramics from coal fly ash can be useful for electrical insulators.
               
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