A State of Art and Prospects of Fly Ash Management

Abstract

The basic data on the volume of formation and composition of fly ash, which is a product of coal combustion at thermal power stations, are given. The analysis of the current state of ways of managing fly ash makes it possible to distinguish the following main directions: physical-mechanical, physical-chemical, biological and combined methods of handling it, which are used in agriculture (use as fertilizers and pesticides; chemical land reclamation: regulation of the structure and pH of the soil); during earthworks (reinforcement of weak and expansive soils, use as tamponage compositions, arrangement of embankments and dams); road construction (strengthening of the soil for the lower layers of the road surface; production of asphalt, cement-concrete mixtures for arranging the foundations of road clothing, as well as crushed stone-sand and gravel-sand mixtures reinforced with cement); building materials industry (cement, concrete, building solutions, geopolymers, bricks, building blocks, glass, glass ceramics, building ceramics, porous ceramics, rolled waterproofing materials); in protective coatings (paints, enamels, enamel glass, shotcrete, heat-protective and heat-insulating coatings); as sorbents and catalysts and their carriers; in mechanical engineering (abrasive, frictional, filtering and lubricating materials, materials for soldering, foundry sand forms or rods); as other materials (pigments, polymer composites, elements of chemical sources of electric current, accumulators of certain substances, carbon nanoparticles (fullerenes, nanotubes), cosmetics and hygiene products); in pyrometallurgical and hydrometallurgical methods of recovery of chemical elements; in alloys and metal matrix composites; for extracting rare earth elements. Currently, the most appropriate methods of disposal of fly ash are either its direct use with a minimal change in its properties, or its use with minimal processing and minimization of the formation of new waste, in particular in the building materials industry and road construction. Bibl. 164, Fig. 3.