Recycling of Coal Fly Ash in Building Materials: A Review

Coal fly ash (CFA) is a type of solid waste produced in the process of coal combustion, which is rich in silicon oxide, aluminum oxide and a small number of heavy metals and radioactive elements. Therefore, CFA is considered a secondary resource with high recovery value. Currently, CFA is mainly reused in the fields of building materials, mine backfilling, soil conditioners and fertilizers, among which the production of building materials is one of the most important ways to realize large-scale utilization of CFA. This paper introduces the physical and chemical properties, classification and environmental impact of CFA and summarizes the utilization status of CFA in building materials such as cement, concrete, ceramics and geopolymers, as well as the management policy of CFA. In addition, the existing problems in the utilization of CFA as a building material are analyzed, and their development prospects are discussed.