Abstract
Each year in Vietnam, to operate the country's thermal power plants, it is necessary to utilize a large quantity of coal. The power plants then generate a large amount of coal fly ash (FA), which is a hazardous solid waste that can seriously affect the environment. There is an urgent need to develop appropriate solutions for treating or reusing the generated FA. In this study, the layout of coal-fired thermal power plants in Vietnam, as well as the country's coal use and FA emissions, are discussed. Research is reviewed on the potential applications of FA in Vietnam, along with related research from the past 20 y worldwide, and is found to demonstrate that the main application of FA is that of a geopolymer in construction, acting as a low-cost adsorbent that removes compounds, organic matter, emissions, metals, light aggregates, backfills, and auxiliary baselines, and synthesizes zeolites. On that basis, FA samples collected in the northern and southern regions of Vietnam were analyzed for their chemical compositions. The results determined that FA throughout Vietnam has the chemical composition, SiO2 + Al2O3 + Fe2O3 over 70 wt%. This is FA of classification F, according to TCVN 10302: 2014 (2014) and ASTM C618. This study concludes that the fly ash originating in Vietnam is suited to the production of porous, super-light materials with a high technical value, such as aerogels or aerogel composites. Such materials as these possess special properties such as a low density, high specific surface area or porosity, low thermal conductivity, sound insulation, low dielectric constant, low optical refractive index, or a high optical transmission capacity, elasticity, durability, or flexibility. The application of Vietnamese FA in the production of materials such as these is recommended by this paper, as a means of countering the environmental pollution problem of coal-fired thermal power plants and promoting the development of advanced materials in Vietnam.
