Technology of utilization and use of ash and slag waste to ensure environmental safety at the region

Abstract

Introduction. By burning coal, thermal power plants receive thermal energy and generate electrical energy. The negative side of this process is the formation of ash and slag waste. The relevance and significance of this problem is due to the fact that technogenic waste from the CHP is not processed, and current ash waste accumulates and occupies huge areas, which removes them from land use. This problem is especially relevant for Almaty, where ash and slag waste from the burning of coal from the Ekibastuz deposit in Kazakhstan is concentrated. Currently, in Kazakhstan, ash and slag waste from thermal power plants is accumulated in the amount of more than 500 million rubles, the reserves of which continue every year. The storage of ash and slag waste leads not only to the seizure of significant land areas, but also causes very significant pollution of almost all environmental components in the area of their location. Therefore, at mining enterprises that have their own thermal power plants, it is very urgent to solve the issues of reducing the burden on the environment by developing technologies for the disposal of ash and slag using them in the production of road surfaces. The purpose of the research. The study of the physico-chemical properties of ash and slag waste to reduce the anthropogenic load on the environment. Research materials. For the research, samples of Ekibastuz coal ash taken from the ash dumps of the CHPP-3 in Almaty were used. Research methods. The work was carried out using a DRON-3M diffractometer to determine the phase composition of ash and slag waste. The chemical composition of fly ash was determined by the X-ray fluorescence spectrometer EDX-8000. The granulometric composition was analyzed using an Analizette 22 MicroTec Fritsch GmbH (Germany). Microphotography of fly ash was taken using a Superprobe-733 scanning electron microscope with software. To determine the physical and mechanical properties of the bases using bitumen-ash-slag binder, the crushed stonegravel-sand mixture is initially mixed with ash-slag. From the finished bitumen – mineral mixture, samples are prepared by pressing – cylinders with a size of 5x5 cm. The ultimate strength was determined for two types of samples. The first are dry, tested immediately after receiving samples by pressing, the second are samples that are tested after water saturation. Research results and discussion. Based on the study of the physic-mechanical properties of the binder with the use of ash and slag, a technology for obtaining BZSHV has been developed. Various compositions are proposed – types of bitumen, depending on the type of base of asphalt concrete mixtures. Studies have shown that the introduction of ash and ash-slag mixtures from the burning of stone and brown coals as a mineral powder for the preparation of asphalt concrete mixtures makes it possible to obtain a material with regulatory physic-chemical characteristics. Conclusion. The results of the study of the main physic-chemical characteristics of the ash of Ekibastuz coal, selected from the ash dumps of the CHP-3 of Almaty city, are presented. It is shown that the use of ash in the manufacture of asphalt pavement will reduce the area of occupied land and the load on the environment, as well as improve the operational characteristics of the pavement. Suggestions for practical application. The results of the research can be useful in solving the environmental problem of utilization of ash and slag waste of the CHP.