A Study of The Characterization of Purified Fly Ash from Xi’an Linyuan Silica Limited

Abstract

Coal is a well-known source of electric power generation all over the globe. Pulverized coal combustion and fluidized coal bed combustion are the two conventional methods involved in the combustion of coal in thermal power plants. Pulverized coal combustion is operated at >14000C while the fluid bed is operated at a temperature between 850-9000C. The first two reactions are the main reactions in the coal combustion process and they are exothermic reactions. CO2 and CO are the first two combustion products. The inorganic minerals in coal are released as waste products in the combustion plants in which fly ash made a large part of the waste materials. Fly ash is formed due to the incomplete combustion of coal. The fly ash from both methods contains SiO2, Al, etc, which are significant constituents. High-grade coal has a higher SiO2 than the low grade. An experiment was conducted by preparing four samples of fly ash heated at 5000C, 6000C, 7000C, and 8000C, and one unheated sample to investigate the chemical composition of the fly ash obtained from Xi’an Linyuan Silica Limited and to prove its suitability as raw material for the fabrication of refractory composites. SEM, EDS, XRD, and FTIR characterization were done on all five samples to determine the chemical parameters of the fly ash. According to the result and analysis of the four characterizations, it was discovered that the fly ash used in this research contains SiO2. SEM/EDS morphological analysis reveals the presence of spherical and a few geometrical crystalline-shaped structures known as cenospheres. Cenospheres are important components for the synthesis of refractory composites. The EDS micrographs show the percentages of silicon and oxygen in the fly ash. The FTIR results show Si-O-Si stretching in all the fly ash prepared samples. In the XRD, it was discovered that the fly ash was purely SiO2.