Phase Transformation of Alumina, Silica and Iron Oxide during Carbothermic Reduction of Fly Ash for Ceramics Production

Fly ash is a by-product from burning of coal. Utilization fly by carbothermic reduction an effective way to recover aluminum, silicon, and iron enhance product-added value. This work focused on the phase transformation Al2O3, SiO2 Fe2O3 during in air. A comparative analysis air nitrogen was made. Thermodynamics performed illustrate possible reactions for residue condensate. X-ray diffraction (XRD), scanning electronic microscope (SEM), energy dispersive spectrometry (EDS) were employed characterize composition, surface morphology, microstructure reduced products. Results show that Fe3Si Fe2Si appear sequentially with increasing temperature. Al5O6N intermediate compound. Residue Al9FeSi3, Al, Si, condensate SiC, AlN C are obtained. β-SiAlON not found residue. Nitrogen involved Al2O3 but Fe2O3. Carbothermic did behave same as nitrogen.