COMPREHENSIVE PROCESSING OF ASH AND SLAG WASTE IN THE CONTEXT OF THE CIRCULAR ECONOMY

Abstract

Ash and slag wastes from thermal power plants are among the largest technogenic formations in Ukraine and pose a significant environmental threat. At the same time, they contain valuable components that can be used as secondary raw materials. The transition to a circular economy requires the development of efficient technologies for their integrated processing. This paper examines contemporary approaches to the comprehensive processing of ash and slag wastes from thermal power plants as one of the key instruments for implementing the principles of a circular economy. The relevance of the study is determined by the substantial volumes of accumulated ash and slag in Ukraine, their adverse environmental impact, and the insufficient involvement of valuable mineral components in economic circulation. Ash and slag wastes from the Zelenodolsk Thermal Power Plant are considered as a complex, multicomponent technogenic system suitable for the production of secondary fuel, iron-bearing and aluminosilicate products. Within the framework of the research, the material, chemical, particle-size and phase–mineralogical composition of the ash and slag, as well as their physico-mechanical properties, were investigated. Magnetic separation in a high-intensity magnetic field, flotation beneficiation with the selection of optimal reagent regimes, and gravity separation of products were employed to separate the components. It is shown that the combination of magnetic separation and flotation ensures the efficient recovery of an iron-bearing product with an Fe content exceeding 40%, a carbon concentrate with carbon recovery above 90%, and aluminosilicate microspheres possessing unique functional properties. The obtained products can be used in metallurgy, the energy sector and the production of building materials. A preliminary economic assessment has demonstrated the high investment attractiveness of the proposed technology and a payback period of approximately 2–3 years.