Investigation of the chemical composition of «fly» ash and its effect on the strength of cement stone

Abstract

The article is devoted to the problems associated with reducing the negative impact of ash and slag waste from the CHP of Kazakhstan on the environment. The fly ash produced in large quantities, as a product of fuel combustion at power plants, negatively affects the external environment, polluting air, soil, sewage, etc.

The article presents the results of the chemical composition of ash and slag waste. Possible ways of using ash are considered. The phase composition of cement stone with the addition of fly ash was also studied using modern methods of analysis: X-ray phase and X-ray fluorescence. It was found that the main macroelements of ash include Si, Al, Fe, O, Ca, Ti, Mg, S, K, Na.

In addition to studying the sizes and shapes of microspheres, the work set the tasks of determining the types of thermoactive phases that make up cement stone during heat treatment; studying structural changes during heat treatment. X-ray phase analysis of ash microspheres showed the following phases: Al₆Si₂O₁₃ mullite, SiO₂ quartz and amorphous glass phase.

The use of ash as a source of aluminum and silicon oxides will not only reduce the use of non-renewable resources, but also obtain materials with improved thermophysical characteristics (strength, heat resistance and thermal conductivity). Choosing the optimal amount of fly ash instead of a part of cement contributes to the formation of the desired structure of cement stone.