Technology of extraction of fuel mass from ash and slag waste in Ukraine

Abstract

Purpose. Development of a technological scheme for the processing of ash and slag waste from coal-fired thermal power plants. The methods. The ash and slag dumps of thermal power plants are made up of the main components - slag, ash and unburned coal particles, drawing up an appropriate scheme for the extraction of coal particles allows the development of an effective scheme for the processing of ash and slag outputs of thermal power plants. The slag is separated from the fly ash by classification on a screen. Next, the method of extracting fuel mass from fly ash is used - the flotation method, based on the selective fixation of coal particles on the surface of air bubbles in the flotation chamber, with subsequent extraction of coal particles into a foam product. The mineral part of the ash cleaned from the fuel mass is ready for use in the road construction industry. Findings. A technological scheme for the processing of ash and slag waste of coal-fired thermal power plants has been developed, which makes it possible to obtain slag, high-quality coal concentrate, and the mineral part of ash. The originality. For the first time, a mathematical model was developed for forecasting indicators of enrichment of ash and slag waste of coal-fired thermal power plants by the flotation method. To predict beneficiation indicators, it is necessary to use three disclosure values: the initial ash content of the coal fraction (Aпd), the number of coal grains (PРЗ), the number of rock grains (PНЗ), provided that the separation characteristics of the beneficiation equipment are experimentally determined in advance. On the basis of the developed mathematical model of forecasting indicators of ash slag waste enrichment, an appropriate flotation scheme for effective extraction of fuel mass was drawn up, which made it possible to develop a technological scheme for processing ash slag waste of coal-fired thermal power plants. Practical implementation. The developed technological scheme for the processing of ash and slag waste makes it possible to obtain slag with a yield of 3.11% suitable for filling industrial roads, coal concentrate with a yield of 25.75% with an ash content of 21.80% can be used as a secondary fuel for thermal power plants or as a raw material for production solid fuel briquettes, as well as the mineral part of ash with a yield of 71.14% with an ash content of 98.10%, which can be used in the road construction industry.