Compositions based on ash and slag wastes from thermal power plants and sodium silicate

Introduction . The main idea of the circular economy is to maximize the use of industrial wastes in the production of materials and reduce the use of natural resources. Ash and slag wastes (ASW), generated during coal firing at thermal power plants and stored in ash-disposal dumps is a promising secondary raw material for the production of artificial ceramic aggregates. Materials and methods . This study investigates the physicochemical properties of ASW classified as Class F according to ASTM C618, an optimal composition based on these wastes is determined, aqueous sodium silicate solution being used as a binder. Cylindrical samples are produced by plastic molding and fired at temperatures of 900-1000°C. Results. It has been established that using 25% aqueous sodium silicate solution as a binder by plastic molding can produce samples with a compressive strength of 7-9 MPa and density of 1200-1250 kg/m³ at firing temperatures of 950–1000°C. These characteristics indicate the material’s potential suitability as an artificial ceramic aggregate for concrete. Discussion and conclusion . Further research implies testing this composition as lightweight aggregate in concrete.