Characterization of α-cordierite glass-ceramics from fly ash

Batches of α-cordierite glass-ceramics, designated as GC-I and GC-II, containing 68 and 64 wt.% fly ash, respectively, were crystallized in the temperature range of 1125-1320 °C. The XRD (X-ray powder diffractometer) of the glass-ceramics show that α-cordierite became the dominant phase in GC-I and GC-II at 1200 °C. GC-I and GC-II, whose solid parts contain 74 and 78 vol.% α-cordierite and whose compressive strengths are 35 and 50 MPa, respectively, have the respective linear thermal expansion coefficients of 1.51 × 10−6 and 1.43 × 10−6/°C. The fly ash α-cordierite glass-ceramics can be employed as kiln furniture, honeycomb substrates for catalysts, and heat exchangers.