VOL 96, No. 4 (2023)

Hollow glass microspheres from sodium borosilicate glass were obtained by high-temperature method, the composition of mass%: 10 Na2O; 8 CaO; 0,3 MgO; 0,2 Al2O3; 9 B2O3; 0,5 SO3; 72 SiO2. It is established that the maximum yield of microspheres up to 87% is observed when using a propane-air torch with the characteristics: the air/propane ratio is 1,3; the maximum temperature on the torch axis is 1900 °C; the opening angle is ~15°; the flow rate of the transporting gas is 0,2 g/s. The hollow glass microspheres obtained in this mode are characterized by a median diameter of 60 microns, an average wall thickness of 1,3 microns, a bulk density of 260 kg/m3 and a calculated strength of 50 MPa.

Compositions of ceramic masses for obtaining wollastonite-containing ceramics using domestic carbonate and siliceous raw materials were developed. The features of the formation of the structure and phase composition of synthesized ceramic materials in connection with the physicochemical properties and operational characteristics were established. The influence of a mineralizing additive (naturally occurring wollastonite) on the processes of sintering and phase formation was determined, the relationship between the physical-technical and thermophysical properties, the firing temperature and the amount of additive introduced was revealed. The results of the research are of theoretical and practical interest in organizing the production of refractory products based on wollastonite.

The influence of the mineralogical composition of clays on the microstructure and frost resistance of ceramic bricks has been studied. The pore radii were calculated by the method of capillary water saturation of the samples, their classification into hazardous and reserve ones was made, and the structural characteristics of the material were determined. It was revealed that a frost-resistant structure, with a predominance of reserve pores of more than 10 microns, is formed in the compositions of brick masses with a montmorillonite content of more than 12% and at a ratio of kaolinite and illite to montmorillonite 3:1, 2:1.

The results of the study of the structure and adsorption properties of the Mo/zeolite composite obtained by enriching the zeolite of the Chuguevsky deposit of Primorsky Krai with Mo nanoparticles followed by sintering are presented.
Its phase and elemental compositions are determined. The adsorption-structural characteristics of the composite are investigated using the BET method. In the work, the specific surface area, total pore volume and mesopore size distribution are determined. The results obtained are of interest for the production of catalytically-active materials based on zeolitic raw materials.

The results of theoretical and experimental studies of the influence of scale deposits on heat exchange processes in vitrified pipes washed by seawater are presented. Experimental studies have shown that during long-term operation of heat exchangers, minor scale deposits with a layer thickness of up to 0.4 mm are observed on the surface of glass coatings of pipes, while a strong scale layer up to 2 mm thick is formed on the inner surfaces of metal pipes. The practical absence of deposits in vitrified pipes is explained by the increased cleanliness of the glass surface and its resistance to aggressiveness of substances dissolved in sea water. This eliminates the formation of large foci of scale on the glass surface and washing off the formed scale with a stream of seawater.

The article presents the results of studies on the chemical-mineralogical composition, acidity and viscosity moduli of basalt and serpentinite of the Arvaten deposit. It has been established that the basalts and serpentinites of this deposit can be used as a raw material for the production of stone casting materials, in the form of mineral wool, and with corrective additives are suitable for the production of basalt fiber.

The article briefly provides basic information about the 24th International Exhibition “World of Glass” held in Moscow, which was directly attended by about 100 companies from 12 countries. New technologies of production and quality control of glass products, the main structural elements of glass furnaces, methods of their high-quality production were demonstrated. Examples of the most successful enterprises of the glass industry are given.

Porcelains were prepared by using kaolin clay, potassium feldspar, and quartz as the raw materials, and ZrO2 as a reinforcing material. This study investigated the effects of the amount of ZrO2, the firing temperature, and the holding time on the porcelain bending strengths and fracture toughness values, and compared the reinforcing effects of two types of ZrO2. The results show that the effect of the two types of ZrO2 (pure ZrO2 and Y2O3-stabilized ZrO2) on porcelain reinforcement were similar and that the optimal porcelain reinforcement was obtained with a ZrO2 content of 6 wt.%, firing temperature of 1300 ?, and holding time of 30 min. The bending strength increased from (58 ± 6) MPa to (89 ± 8) MPa (pure ZrO2) and (87 ± 8) MPa (Y2O3- stabilized ZrO2), with the respective growth rates reaching 62 and 58 %. Radial stress was generated in the matrix during the cooling process because of the difference between the thermal expansion coefficients of ZrO2 particles and the matrix.
This increased the porcelain strength. The phase transformation of ZrO2 improved the fracture toughness of the porcelain, but had little effect on reinforcement of the porcelain.