Glass and Ceramics最新文献

This study examines the impermeability and sorption properties of palygorskite and other clays from the Borshchevskoye and Voskresenskoye deposits, which are overburden associated with the extraction of raw materials for the cement industry. Experimental findings demonstrate that the filtration coefficients of the studied samples comply with current regulatory standards, confirming their suitability for use as impermeable barriers for municipal solid waste (MSW) landfills. The palygorskite clay sample exhibited a filtration coefficient of 8 × 10 ^–10 m/sec. Key sorption characteristics of the palygorskite clay sample were also established, including a specific surface area of 85.1 m²/g and specific micro- and mesopore volumes of 0.0138 cm³/g and 0.127 cm³/g, respectively. The efficiency of the clay in purifying individual model solutions under static conditions was evaluated, demonstrating a removal efficiency of > 94% for heavy metals from aqueous solutions and > 60% for petroleum products.

This study investigates the properties of a borophosphate glass (BPG) matrix incorporating lithium chloride (LiCl) as a simulated spent electrolyte, a type of radioactive waste (RAW) generated during the pyrochemical reprocessing of spent nuclear fuel (SNF). X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses confirmed the amorphous structure and homogeneity of the synthesized material. The thermal properties of the glass were characterized using differential scanning calorimetry (DSC) and thermal conductivity measurements. The incorporation of LiCl had no significant effect on the glass transition temperature, which remained at approximately 410°C; however, it influenced the electrical conductivity, as determined by electro-chemical impedance spectroscopy. Mechanical strength and hydrolytic stability tests were carried out in accordance with established requirements for RAW immobilization matrices. The analysis of surface morphology revealed the formation of a diffusion layer due to the leaching of sodium ions into the solution. The results demonstrate the feasibility of using the selected glass composition as an immobilization matrix for LiCl-based spent electrolytes.

This study examines the dielectric properties and harmonic distortion coefficients of barium titanate ceramics fabricated using a mixture of BaTiO₃ powders with particle sizes of 400 nm and 50 nm, sintered at varying temperatures. The findings demonstrate that as the content of the fine-grained component (50 nm) increases from 0 to 100%, the permittivity ε(x) and harmonic distortion coefficient γ(x) exhibit non-monotonic behavior, reaching maximum values at x = 0.25 and x = 0.30, respectively. This trend is likely attributed to alterations in packing density resulting from variations in the percentage composition of the components.

Titanium oxide powders with different crystal structures and textural characteristics were synthesized. Metallic titanium and rutile (rutile particle size 25 μm, specific surface area 3 m²/g) were used as starting materials for the synthesis of titanium salts, which were subsequently decomposed. Titanium salts were obtained by interaction with mineral acids and ammonium carbonate. The obtained salts were thermally decomposed or hydrolyzed by the addition of ammonium hydroxide, which resulted in the precipitation of titanium oxide. The phase composition of the synthesized samples included rutile and anatase, as well as impurities of titanium fluoride observed at low firing temperatures. A relatively simple and economically feasible method for the synthesis of titanium oxide with specific surface area up to 92 m²/g has been proposed. This method involves simple chemical transformations, which include thermal decomposition of synthesized titanium halides. The best of the synthesized anatase samples had the shape of irregular polyps, specific surface from 56 – 92 m²/g, and particle size in the range of 20 – 60 μm.

The methodological approach to the creation of a hardware-software solution for debugging and testing of algorithms and control systems of actuators of a glass forming machine in real time mode is presented. Model tests are used to evaluate the compliance of algorithms with technical specifications and their reliability. The tests were carried out on a test bench built on the basis of an industrial sample. On the test bench the operation of the object is modeled, parameters are recorded and transferred to the monitoring system for post-processing. In the course of testing, the component base of various manufacturers available under the sanctions policy was tested. It was confirmed that such a stand can be used for rapid prototyping of control algorithms, semi-natural testing, and training of glass industry specialists. The independent control of the process control system is a contributing factor to the development of industrial equipment engineering and the localization of critical technologies. Consequently, this contributes to the formation of technological sovereignty.

This paper examines mesoporous TiO₂-montmorillonite composites synthesized by hydrothermally activated impregnation (115°C, 0.5 – 5.0 h) of mechanochemically and thermally activated montmorillonite with titanium polyhydroxy complexes. The materials were characterized using x-ray diffraction (XRD), infrared (IR) spectroscopy, low-temperature nitrogen adsorption/desorption, scanning electron microscopy (SEM), electrophoretic light scattering, and energy-dispersive spectroscopy (EDS). The duration of hydrothermal treatment significantly influenced the crystallite size of titanium dioxide and the anatase-to-rutile phase ratio, as well as the surface morphology and textural properties of the composites. Photometric analysis was used to evaluate the adsorption capacity and photocatalytic activity of the composites toward Rhodamine B as a model dye. Overall, hydrothermal treatment substantially enhanced the photocatalytic activity of the composites. However, prolonged treatment duration resulted in a decline in this effect. The obtained composites exhibited a pronounced synergistic effect of adsorption and photocatalysis in removing Rhodamine B from a highly concentrated (40 mg/L) aqueous solution.

The process of soft mechanochemical synthesis of CuO/ZnO/Al₂O₃ composites using copper/zinc hydroxocarbonates and alumina as starting materials was studied. The regularities occurring at the stage of mechanochemical activation and sucsequent thermal treatment were investigated by means of x-ray diffraction (XRD) and synchronous thermal analysis methods. The influence of the energy intensity of the mill on the textural properties of the composite was demonstrated. Low-temperature nitrogen adsorption-desorption showed that in the process of mechanochemical synthesis the total specific surface area of the samples changes insignificantly, while the type of processing has a significant effect on textural properties including pore size distribution, active surface area, and copper dispersion. Temperature ranges of composite activation for catalytic applications were obtained by the method of thermo-programmed reduction. The positive influence of the mechanical activation on the formation of the composite structure was observed. This allows its use as the main component of the catalyst for the production of ammonia, hydrogen, and methanol.

The physicochemical properties of the commercial bentonite S-4205-02 (Bentovin) and its structural parameters were determined. Clay agglomerates were predominantly up to 10 – 20 microns in size. X-ray spectral analysis revealed a relatively high content of Fe₂O₃, Na₂O, CaO, which corresponds to the iron-aluminum variant of montmorillonite with a predominance of Na⁺ and Ca²⁺ ions in the interlayer space. The presence of potassium indicates the presence of illite. According to XRD data, the main component of the product is montmorillonite with impurities of quartz/cristobalite, kaolinite, illite, and hematite. Thermal analysis curves and IR spectrum of bentonite were analyzed. The textural characteristics of the powder were determined. The specific surface area was 58 ± 6 m²/g. Based on bentonite and orthophosphoric acid, a geopolymer bentonite-phosphate binder was synthesized for the first time. XRD and IR spectral analysis show that the interaction of aluminosilicate powder with orthophosphoric acid leads to the complete destruction of the montmorillonite structure with the formation of aluminum and silicon phosphates.

An energy and resource saving plasma technology for glazing of autoclave-hardened building materials was developed. It is found that the introduction of colemanite into the composition of the initial charge allows to increase the performance indicators, including frost resistance, water resistance, and microhardness. The characteristics of the formation of the macrostructure and microstructure of the glaze layer at the front surface treatment by plasma jet are studied.

Natural quartz sands, widely used in glass, refractory, ceramic, foundry, and other industries, frequently do not meet the particle size distribution requirements set by the industry standards. This study proposes an effective method for processing silica sand to enhance the particle size distribution using a pneumatic cross flow separator.