Recycling of Prydniprovska thermal power plant fly ash

Purpose.To confirm experimentally the feasibility of complete fly ash recycling at Prydniprovska Thermal Power Plant (TPP) by its refining into industrially valuable products using gravity classification of dry ash from electrostatic precipitators and water-gravity separation of ash from a dump. Methods. Classification of fly ash has been carried out on the modernized processing equipment in the laboratory in two ways. First, ash pneumatic separation was done directly from the electrostatic precipitators using a specially selected vibrating screen. The second way involved hydro-separation of the original product from the ash dump using the upgraded centrifuges and hydrocyclones. Findings. Technological solution for complex processing of fly ashes, based on the “dry” gravitational separation of ash from electrostatic precipitators and “wet” gravitational separation of ash from thermal power plants and storage dumps has been developed. It is established that the addition of active ash up to 33% to 1 m3 of concrete allows to save up to 25% of cement and increase strength of concrete structures up to 5%. Addition of products manufactured from thermal power plants waste for production of building materials allows to reduce the share of energy consumption up to 20 – 25%, which is essential for the competitiveness of construction products. A mixture of alumina-silica products can reduce clay usage in metallurgical industry to 50%. Carbon products are cheap substitutes for production of certain kinds of sorbents. The proposed project solution allows to reduce resource consumption, decrease human impact on the environment, and increase energy potential of the region. Originality. The time dependence related to surface activity decrease of the resulting recycling products from the dry fly ash directly from electrostatic precipitators has been established. Recycling of fly ash into industrially useful products by dry gravity separation allows to achieve the best physical parameters of the raw materials with the highest specific activity. Practical implications. Implementation of the research results will be instrumental in receiving such industrial products as: components in the manufacture of building materials (concrete, foam and aerated concrete, brick), heat insulating material, raw materials for steel industry, sorbents for chemical industry and deoxidants for metallurgical industry. The proposed technological solution is completely environmentally safe and non-waste.