VOL 98, No. 8 (2025)

The article presents the results of a study devoted to the development of a laser-induced breakdown spectroscopy (LIBS) method for monitoring the homogeneity of the chemical composition of optical glasses. A quantitative method for studying lead distribution over the surface area of samples in lead-silicate glasses based on LIBS has been developed. The parameters of laser radiation action on the surface of lead-silicate glasses (pulse energy, laser pulse repetition rate, laser wavelength, delay between the pulse and registration of the analytical signal) have been optimized. The minimum step of scanning the chemical composition over the surface area of the sample has been set at 300 ?m.

Composite ceramic materials based on SiO2–Al2O3–ZrO2 nanopowders were obtained by sintering and their properties were studied. Before sintering, the powders were subjected to mechanical activation in a planetary ball mill using zirconium dioxide balls as grinding bodies. The activated powders were pressed under pressing pressures of 50, 100, 200 and 300 MPa. Consolidation was carried out in an atmospheric high-temperature furnace at 1700 ?. The surface of the sintered bulk samples was examined using a scanning electron microscope. Elemental analysis made it possible to establish patterns in the distribution of chemical elements. It was found that in all the studied samples two phases were formed – Al6Si2O13 and ZrSiO4. The porosity of the samples was determined and the dependence of this parameter on the applied pressing pressure was established. The mechanical properties of the samples were studied using nanoindentation: indentation hardness and elastic modulus, and the bending strength limits of the studied samples were determined during Scratch testing. The crack resistance of the samples was determined by the indentation method using the Marshall-Evans relationship. The effect of the ratio of the initial components and the applied pressing pressure on the physical and mechanical properties of the resulting composite ceramics was determined.

The paper presents the results of the studies of borophosphate glasses containing an additive of the FLiNaK salt, an eutectic mixture of alkali metal fluorides of the composition 46.5 mol. % LiF – 11.5 mol. % NaF–42 mol. % KF, as one of the types of radioactive waste from the developed molten salt nuclear reactors. The obtained glasses demonstrate a high percentage of FLiNaK inclusion, reaching 20…25 wt. %, and retain a homogeneous amorphous structure with a uniform distribution of elements throughout the volume. Starting with a FLiNaK content of 25 wt. %, the glasses crystallize with the formation of the elpasolite phase K2NaAlF6. According to X-ray diffraction studies, depending on the fluoride content in the glass, certain regularities were found indicating the presence of a correlation between the transformation of the local structure of the glass and the formation of the crystalline phase, which will be further studied in more detail. Studies of the chemical and mechanical stability of the obtained glasses with a FLiNaK content of no more than 20 wt. % indicate that these glasses meet the regulatory requirements for glass matrices used to immobilize radioactive waste. At the same time, the dependence of these properties on the FLiNaK content revealed the presence of an extremum at a value of 7 wt. % FLiNaK, but no correlations with structural changes were detected.

Silica adsorbents with organosilsesquioxane fragments containing organic radicals have been obtained for use in the adsorption separation of oxygen-argon mixtures by the PSA method. The sol-gel scheme of the process of directed copolycondensation of the reagent mixture was chosen as the basic method for the synthesis of adsorbents. The obtained materials were characterized by thermogravimetry and low-temperature nitrogen adsorption. The results of studying their adsorption properties for oxygen and argon are presented. The highest selectivity for argon was demonstrated by a silica sample containing (diethylaminomethyl)silsesquioxy groups with the maximum value of the total volume of micro- and mesopores and a wide distribution of mesopore volumes by radii.

Restoration of natural ecosystems has now become one of the main tasks requiring urgent search for effective solutions. Due to the serious negative impact of mass pollution on the environment, it is important to actively participate in the restoration of this environment. The most promising option for recycling drilling mud is the synthesis of effective materials such as wedging agents, slamolites and keramstenes. In addition, the use of drilling mud as raw materials will reduce the industry's need for natural raw materials. The article describes the physico-chemical studies of drilling waste and their possibility of use for the synthesis of effective aluminosilicate materials.

The possibility of using waste from the enrichment of ferruginous quartzites of KMA and waste from vanadium production for the plasma synthesis of marblite and structural elements of a plasma glass furnace is considered. The operational parameters of marblite, such as water resistance, frost resistance, microhardness, and phase composition, have been studied. The color characteristics of marblite are determined in the CIE L*a*b* system.

The article presents the results of a study on the development of a composition of technical ceramics for ceramic grinding bodies and the influence of dispersed oxide on its basic properties. It is shown that waste from a gas processing industry catalyst was used as an alumina-containing component. Dispersed aluminum oxide was obtained from chemical reagents by the citrate sol-gel method. It has been established that the introduction of nanodispersed aluminum oxide in an amount of 3 wt. % over 100 wt. % of the total mass improves the abrasion coefficient, acid resistance, density, and strength of the developed samples of technical ceramics.