Structure and crystallographical formula of coal fly-ash glass-ceramics

CaO-Na2O-SiO2 glass-ceramics was prepared from coal fly-ash by sintering method. Structure and chemical composition of crystal phase was investigated by X-ray diffraction (XRD), fourier transform infrared(FTIR)and electron probe micro-analyzer-wave dis-persive spectrometer (EPMA-WDS). The results show that the main crystal phase in the glass-ceramics is α-wollastonite, but whose crystal lattice is slightly different from card 27-0088. Compared with the standard IR spectra, the absorptions of Si-OB(OB represents the non-bridge oxygen) and Ca-O shift to higher frequency. Using the anion hydrogen equivalent method, the crystallographical formula of the wollastonite is identified.