Studying the properties of ash and slag waste for use in the manufacture of construction products

Abstract

Purpose. The research purpose is to study the physical-chemical properties of ash and slag waste generated during the coal combustion at the Ekibastuz field in Kazakhstan, to determine the possibility of using waste as a secondary resource to reduce the negative human impact on the environment. Methods. The research uses the methods of X-ray phase and differential thermal analysis, as well as chemical analysis. The X-ray phase analysis makes it possible to determine the phase composition and structure of ash and slag wastes, while differential thermal analysis is used to study their behavior with temperature changes. A chemical analysis is performed to determine the composition of ash and slag. Findings. The chemical and granulometric composition of ash and slag waste from the Ekibastuz field coal combustion has been determined. Analysis of the ash chemical composition showed that its main components are silicon and aluminum oxides, as well as a significant amount of iron oxide. The results obtained confirm the possibility of using ash and slag waste as a secondary raw material to reduce the negative impact on the environment. Originality. It has been revealed that the thermal conductivity, ultimate strength and water-absorption of ceramic brick samples depend on the amount of ash added and the firing temperature. The possibility of obtaining building materials with minimum cement content has also been substantiated, which is a new and promising approach, given the high cost of cement as the main building material. Practical implications. The practical value of the research is in solving environmental problems associated with the use of ash and slag waste. Using these wastes as a secondary raw material, it is possible to reduce the anthropogenic burden on the environment, as well as the volume of ash dumps. In addition, vacant land previously occupied by ash and slag mixtures can be used for economic purposes.

Theoretical substantiation of water inflow into the mined-out space of quarries mining hard-rock building materials

“…It should also be noted that when mining non-metallic hard-rock mineral deposits, the greatest water cut is observed in the zones of tectonic faults [44][45][46] technogenic disturbances [47,48] and weathering crust [49,50]. As for the undisturbed rock mass, the water inflow in such deposits is extremely small and does not entail significant costs [51] .…”