Application of hard coal combustion residuals in the production of ceramic building materials

Abstract

The combustion of solid fuels results in solid by-products, i.e. slags and ashes. This waste is a potential source of many valuable mineral materials that should be used to the maximum extent. The amount of solid waste generated in combustion processes depends on the quality of coal and its natural ash content. In addition, the amount of waste is increased by a portion of unburnt coal depending on the furnace efficiency. The paper presents the results of research on the application of combustion waste as an additive to the ceramic mass used in the production of ceramic clinker products. Two furnace slags differing in origin were used in the investigations. Their physicochemical characteristics and the effect of this waste on the properties of clinker ceramics were determined. The required test specimens were formed from plastic ceramic masses containing wt. 30% of the waste. After firing at temperatures ranging from 1100 to 1200 °C, the linear shrinkage, water absorption, open porosity, apparent density and compressive strength of the obtained materials were determined. The results of the conducted research indicate that combustion waste can be considered as a valuable secondary raw material for the production of ceramic clinker products, because it intensifies the sintering process of clinker ceramics.