Abstract
The whole world aims to reduce coal consumption, but despite such a policy, there are countries where its consumption continues to grow (China, India). If coal consumption grows, the volume of ash and slag waste (materials) that must be utilized and processed to obtain final products grows. The main elements included in the by-product of coal combustion are SiO2, Al2O3, and Fe2O3. The paper provides a review of the use and processing of ash and slag materials for recycling as well as potential directions for their disposal: as well as potential directions for their disposal: cement production, geopolymer, in zeolite synthesis, microsphere separation, in agriculture, in land reclamation, in phytoremediation as reagents for water purification, in road construction for backfilling abandoned mines. The authors employed physicochemical analysis methods to confirm that the primary components of the material are SiO2 (65.9%) and Al2O3 (22.5%). It has been established that a high proportion of silicon and aluminum can be an effective raw material for construction and geopolymer materials, as well as in the production of ceramic products. Availability of Fe2O3 (5.54%) suggests possibilities for its use in catalytic processes and pigment production. The alkaline reaction of the aqueous extract of the ash (pH = 9.25) correlates well with its chemical composition and confirms the presence of active alkaline components in the material. This alkaline nature of the ash favors geopolymerization processes and increases the material's reactivity when interacting with acidic activators. Additionally, the minor presence of TiO2 (1.11%) may improve the mechanical properties of ash-based materials.