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.

The synthesis of iron-containing oxide nanoparticles is of interest in medicine, electronics and ecology due to their unique physical and chemical properties, such as magnetic, catalytic and adsorption properties, which allow their use in various technological processes. In this regard, this article presents the results of obtaining nanoparticles of iron-containing oxides and studying their physical and chemical properties. It is known that stabilization with natural polymers is of great importance in the production of metal nanoparticles. Therefore, in this work, the synthesis is carried out at high temperature by stabilization with potassium humate. To study the properties of the resulting iron-containing nanoparticles, methods of X-ray phase analysis, transmission electron microscopy and infrared spectroscopy were used. As a result of physicochemical studies, the heterogeneity and monodispersity of the synthesized metal nanoparticles was established. The average particle size of the synthesized samples was 8.3 nm, the crystal lattice parameter was 0.8426 nm. The result of the study using IR spectroscopy confirms the assumption of oxidation of the samples. In addition, it was found that the prepared samples have a high degree of crystallization. Transmission electron microscopy revealed no differences in the sizes of nanoparticles. Pure iron oxide is not formed during the synthesis of iron nanoparticles using the method used in the research work. The unique properties of iron-containing oxide nanoparticles obtained as a result of research are promising for the creation of innovative technologies and solutions aimed at improving the quality of life and sustainable development of society.