Effect of mineralogical phase and chemical composition of fly ash on electromagnetic wave-absorbing properties

In order to explore the electromagnetic radiation protection function of fly ash as building materials, Scanning Electron Microscope (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Mössbauer were used to analyze the chemical composition and mineralogical phase of two types of fly ash. Electromagnetic parameters of the samples were analyzed and discussed in detail at the frequency range of 1∼18 GHz. The results showed that fly ash had electromagnetic wave absorbing property due to porous carbon grain and iron oxide, and that dielectric loss was more than magnetic loss for fly ash and electromagnetic property of type III was more than of type I. There were several absorbing-wave interference peaks at the frequency of 118 GHz, at thickness of 1020mm epoxy-based fly ash. The cement-based fly ash showed electromagnetic wave-absorbing properties at 10∼18 GHz and the biggest absorption reached 14.5 dB at 16 GHz at the thickness of 20 mm, so the fly ash should be expected to be a building material for electromagnetic protection.