Glukhoverya M. The technology of increasing the extraction of fuel mass from ash and slag waste of coal-fired thermal power plants

The presented dissertation is a completed scientific research work, which is dedicated to the solution of an actual scientific task, which consists in the development of a technology for increasing the extraction of fuel mass from the accumulated ash and slag waste of coal-fired thermal power plants of Ukraine, which is achieved by establishing technological parameters that have an impact on the process of flotation extraction of fuel mass from the ash and slag waste of thermal power plants, the development of a regression model for forecasting the ash content of the fuel mass concentrate depending on the influencing factors during flotation, the development of a mathematical model for forecasting indicators of enrichment of ash and slag raw materials, the development of a mathematical model that makes it possible to theoretically find the optimal consumption of the reagent-collector necessary for of the flotation process. On the basis of the analysis of literary sources, the question of the formation ash and slag waste of thermal power plants and the volume of their accumulation, as well as their annual growth, was considered. When coal is burned at coal-fired thermal power plants, an unburned part of the fuel is formed, which consists of ash and slag. The existing technologies for the processing of ash and slag waste of thermal power plants do not ensure sufficient quality of the processing products. A comparison of existing problems and methods of solving them made it possible to form the scientific tasks of the research. The perspective and economic profitability of the technology must be provided by high-quality processing products with minimal energy consumption, therefore, the study of the beneficiation properties of ash and slag the thermal power plant will allow the development of a technological scheme for increasing the extraction of fuel mass, which will create a scientific basis for the effective processing of this waste. The composition of ash and slag waste granulometric and fractional characteristics were studied. The chemical composition of ash and slag raw materials, the content of coal particles in size classes are presented. According to fractional analysis, the limit concentration of coal particles is determined. The parameters that affect the process of extracting coal particles from ash and slag waste using the flotation method were studied, and the obtained qualitative and quantitative indicators of processing products obtained on two mechanical (MFV) and ejector (EFM) type flotation machines were compared. During the flotation of fly ash, the best results were obtained on the flotation machine of the EFM ejector type, the yield of the foam product was 18,6% with an ash content of 25,1%, compared to the flotation machine of the mechanical type of the MFV, where the ash content of the foam product was 36,5% with an average yield of 21,1%. The optimal consumption of flotation reagents was determined with the help of laboratory studies. The optimal consumption of reagents at the level of no more than 3500 g/t of the collector and foaming agent up to 250 g/t was determined experimentally, and the necessary flotation time was determined.