The processes of thermochemical hardening of aluminosilicate glass are investigated. The glass was processed in a KNO3 melt under industrial and laboratory conditions at 440…480 °C for 1…120 h. The effect of processing modes on glass properties was evaluated using Vickers microhardness measurement, spectrophotometry, magnetophotoelasticity to measure compressive stresses, and local birefringence analysis to determine the depth of the compressed layer, as well as X-ray fluorescence to evaluate cation exchange. The link between the temperature-time parameters of ion exchange and changes in glass’s structural, mechanical, and optical properties was revealed.
This paper presents a study of the possibility of synthesizing a thermal insulation material, sludge, based on oil production drilling waste. Samples of drilling mud were collected at the Komsomolskoye oil and gas condensate field and prepared for further use, including drying and milling. Its chemical and phase compositions were determined, confirming the possibility of using the waste for synthesizing thermal insulation materials. A series of raw materials for synthesizing sludge, as well as temperature and time modes of firing, were developed. A study of the physical and chemical properties of the synthesized samples was conducted. The optimal composition for synthesizing sludge was determined, which includes 80 % of drilling mud, 15 % of sodium hydroxide, 5 % of sodium tetraborate, 10 % of water, synthesized at a temperature of 1000 °C and having a density of 745.05 kg/m3.
Against the backdrop of globally tightened environmental regulations, particularly in the Russian Federation, conventional gas-cleaning methods (cyclones, bag filters, electrostatic precipitators) used in the glass industry are becoming insufficient. These are only effective for capturing suspended particles yet not capable of removing the gaseous marker pollutants at the required level: NOx, SO2, CO. The study is aimed at developing and experimentally validating a highly efficient integrated system that enables 90…95 % removal of gaseous pollutants and approximates 100 % removal of solid particles. A silica/mullite fiber-based reducing catalyst produced entirely from domestic materials (20 cm3) achieved 95 % NO conversion at 350 °C in laboratory reactor tests. The catalytic filter element (with a surface area of 0.02 m2) installed in the pilot setup showed high simultaneous removal efficiencies for multiple pollutants: NOx – 92 %, SO2 – 96 %, at an operating temperature of 380 °C. The authors proposed an integrated purification train that includes an acid-gas neutralization reactor, reagent-dosing systems (for lime, caustic solution, and ammonia water), an inertial separator, a ceramic catalytic filter unit, as well as lime and spent reagent silos. The study was conducted using the Ceramic Pulse-Jet Filter, T Modification, Catalytic Configuration laboratory and pilot testing unit (Bakor R&D Center).
The paper investigates the physical and technical properties of a composite material based on white-burning clay from the Kornilovsky deposit of the Tomsk region with the addition of a gas-forming agent. The physico-chemical properties of clay have been determined. The physical and technical properties of heat-insulating refractory products based on the white-burning clay of the Kornilovsky deposit have been determined. The applications of the material in industry with high-temperature technologies are proposed. The work is a continuation of the article “Investigation of the properties of clays of overburden rocks of the Kornilovsky deposit of the Tomsk region for use in the refractory, ceramic and petroleum industries”.
The effect of a combination of water-soluble magnesium and aluminum salts on the physicochemical properties of the obtained aluminomagnesium spinel was studied. It was shown that the formation of aluminomagnesium spinel occurs in the range of 800…1050 ? from synthesized xerogels based on different ratios of magnesium and aluminum chlorides and nitrates. It was found that the crystalline structure of the spinel is completely formed during heat treatment of xerogels from synthesized pairs of AlCl3 + MgCl2 salts at 900 °C and holding for 60 minutes, while they have smaller crystallite sizes compared to other heat-treated xerogels. It was revealed that a higher temperature of 1050 ? is required to obtain spinel from xerogels synthesized on the basis of pairs of Al(NO3)3 + MgCl2 and Al(NO3)3 + Mg(NO3)2 salts.
Yttrium aluminum garnet (YAG) powders were synthesized via chemical precipitation, both with and without the addition of ammonium sulfate as a dispersant. The impact of the dispersant on the particle size distribution of YAG powders calcined at various temperatures was investigated. Powder morphology was analyzed using scanning electron microscopy (SEM), revealing significant differences in both morphology and particle size depending on whether the dispersant was present. The kinetics of phase transformations in the ceramic powders, with and without ammonium sulfate, were thoroughly examined using X-ray diffraction (XRD) and simultaneous thermal analysis (STA). Based on the data obtained, a novel mechanism was proposed for reducing agglomeration in YAG ceramic powders through the use of ammonium sulfate as a dispersant. This mechanism entails the formation of intermediate phases, namely yttrium sulfate and yttrium oxysulfate, followed by their gradual decomposition to yield the garnet phase.
Nanocrystalline powders of yttrium scandium aluminum garnet (YSAG) doped with neodymium Nd3+ and samarium Sm3+ cations were synthesized by chemical precipitation. Their morphology, phase and granulometric composition have been studied. Three types of samples were produced from the obtained ceramic powders using various pressing methods: standard non-composite reference samples, samples with a composite structure of the same composition, and samples of composite ceramics with different layer compositions. The samples of the first and second types demonstrated high transparency and uniformity of the microstructure. A slight decrease in the light transmission of samples of the third type is due to the presence of a certain number of residual pores and inclusions near the interface of the layers, the probable nature of the formation of which is associated with differences in the kinetics of sintering compositions. The influence of the parameters of uniaxial and cold isostatic pressing of composite compacts on the microstructure and optical properties of YSAG:Nd3+/YSAG:Sm3+ composite ceramics was also investigated. It is shown that at the interface between the YSAG:Nd and YSAG:Sm layers there is a region of gradient doping with samarium cations, the extent of which may presumably depend on the pressing conditions and sintering parameters of composite compacts.
Yttrium aluminum garnet doped with ytterbium (YAG:Yb) ceramic powders were synthesized using the chemical precipitation method, from which optical ceramic samples were fabricated. Dispersants, namely polyvinylpyrrolidone and ammonium sulfate, were employed during powder synthesis, washing, and milling. The results presented include data on the phase composition, specific surface area, scanning electron microscopy, and particle size distribution of the ceramic powders. It was noted that the addition of polyvinylpyrrolidone and ammonium sulfate to the reaction mixture, as well as to the washing and milling solutions, alters the particle size distribution and specific surface area of the powders, while also influencing the kinetics of phase transformations. Furthermore, the influence of these dispersants on the optical properties of YAG:Yb ceramics and the number of macrodefects was revealed.
A study was conducted on obtaining powders for microwave dielectrics from zinc oxide using deep eutectic solvents. As a result of using various solvents, a monophase ZnO powder is formed, the particle size and phase composition of which can be controlled by changing the calcination temperature. Deep eutectic solvents make it possible to obtain zinc oxide precursors by interacting the corresponding deep eutectic solvent with water, without using alkalis or ammonium hydroxide, which gives reason to consider such synthesis more environmentally friendly. Zinc nanoparticles obtained at 500 °C have a pronounced antimicrobial effect on Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli).
Abstract. In recent years, the issues of obtaining clinker ceramics have become as relevant as possible, including – this is due to the tasks of import substitution. Clinker ceramics is a product that is used in aggressive environments and its characteristics are as close as possible to high-strength concrete. For production, it is necessary to maintain a balance between the cost of production and the achievement of characteristics corresponding to clinker ceramics. This article discloses the relationship between the composition of the raw components of ceramics, their granulometric composition, firing mode and its strength characteristics obtained in laboratory conditions from low-melting and refractory raw materials Siberian region, as well as the introduction of the sintering additive albitofir. The purpose of the work is to develop a composition for the production of clinker ceramics with water absorption indicators W not more than 4 %.
