Coal Fly Ash Beneficiation: A Substitute Material for Portland Cement – A Review

The generation of coal fly ash (CFA) as a by-product from coal-fired power plants presents significant environmental challenges due to its massive volume and potential for pollution. However, CFA has demonstrated promising potential as a supplementary cementitious material (SCM) in the construction industry, particularly as a partial substitute for Portland cement. This review explores current advancements in the beneficiation of coal fly ash, various techniques employed to enhance its properties, and its application as a cement substitute. Notably, studies have reported that incorporating up to 30% beneficiated CFA can reduce CO₂ emissions from concrete production by approximately 20% while enhancing long-term durability. Furthermore, Class F fly ash has shown to improve sulfate resistance and reduce alkali-silica reaction potential in concrete, while mechanical beneficiation methods can lower unburned carbon content to less than 2%, making the material more compatible with cement formulations. The study also examines environmental, economic, and technical benefits, along with limitations and future prospect for integrating beneficiated fly ash into sustainable construction practices.