Kurilov V. Justification of technological parameters and development of methods for extracting silicate raw materials from fly ash of thermal power plants.

The dissertation is dedicated to solving an important scientific and practical problem: determining the physical characteristics of loose and moist fly ash, the regularities of changes in hydraulic characteristics, and the indicators of compressed sedimentation and flotation of ash particles in upward flows depending on the density of suspensions. It establishes rational parameters for hydraulic separation to extract silicate raw materials with low carbon content from thermal power plant (TPP) fly ash, which is of significant importance for increasing the efficiency of the development of technogenic deposits and reducing the use of primary resources. This would reduce the load on ash dumps and their negative environmental impact, contributing to the sustainable development of industrial regions in Ukraine. The aim of the work is to establish the physical characteristics of current dry and settled ash, the regularities of hydraulic separation of ash particles of different sizes and densities in aqueous ash suspensions of various densities, to determine rational modes of hydraulic separation, and to develop methods for processing both dry and settled ash to obtain silicate construction raw materials with a standardized content of carbon-containing fraction, which represents industrial and economic interest. The scientific significance of the work lies in determining the dependencies of changes in hydraulic characteristics of ash suspensions based on density, developing mathematical correlation models, and establishing the patterns of compressed sedimentation of ash particles across a wide range of ash suspension densities. It also defines limitations and establishes the coefficients of Stokes' law for compressed sedimentation of carbonaceous and aluminosilicate fractions in ash suspensions of various densities and substantiates the mode parameters of new technologies for processing both dry and wet-settled fly ash from TPPs to obtain silicate construction materials with a standardized carbon-containing fraction. The practical significance of the work is in the development of engineering methods, algorithms, and software for calculating the characteristics of fine-grained suspensions, the velocity of compressed sedimentation of fly ash particles in ash suspensions of various densities, improvement of experimental methods for measuring the density of solid phases and the velocity of mass sedimentation of fine-grained composite suspensions, and determination of the range of rational mode parameters for the hydraulic separation of ash and its individual size fractions. Additionally, new prospective schemes for processing both current dry ash from electrostatic precipitators and settled wet ash from TPP ash dumps are developed based on process regularities, along with the development of new methods and technical solutions for which six patents of Ukraine have been obtained.