VOL 92, No. 8 (2019)

One- and multicomponent sintering additives for ceramics based on aluminum oxide are presented. It has been established from the literature that the use of one-component additives is less effective than multicomponent, due to their higher melting temperatures and the impossibility of simultaneously influencing a number of properties of the target material. Due to the synergistic effect, the use of multicomponent additives makes it possible to achieve a simultaneous improvement in the properties of sintered samples based on aluminum oxide, in particular, an increase in the degree of compaction (porosity & # 8776; 0.1 & # 37;) of samples, a decrease in the sintering temperature to 1400 & # 176; C, preservation of a fine-crystalline structure (average grain size & # 8776; 3 microns), an increase in the value of crack resistance & # 8776; 5.86 MPa • m1 / 2 and ultimate strength in bending & # 8776; 600 MPa

The results of studies of the porosity of heat-efficient ceramic materials based on clays of various mineralogical composition with a glass-porous component (SPC) and their effect on frost resistance and thermal conductivity are presented. It was found that the content of minerals of the illite and montmorillonite subgroup in clays in compositions with SPC determines the optimal quantitative ratio of meso-, macro-, and also & # 171; hazardous & # 187; reserve and & # 171; safe & # 187; pores, which leads to a decrease in the coefficient of thermal conductivity and high indicators of frost resistance of materials

A sol-gel process for producing aluminum-magnesium spinel fibers from a fiber-forming precursor based on aluminum and magnesium polycarboxylates is considered. The principal possibility of obtaining discrete fibers of stoichiometric spinel by the method of aerodynamic spraying is shown. The results of studies of surface morphology, fine structure and phase composition of fibers are presented. It is shown that the structure of the fibers obtained is uniform, polycrystalline, and there are practically no non-fibrous inclusions in the pulp. The phase composition corresponds to the spinel stoichiometry

Investigations of the effect of fly ash generated from the incineration of municipal solid waste on the properties, durability and environmental toxicity of fired luminosilicates are presented. In the manufacture of aluminosilicates, fly ash was introduced into the charge in an amount of 2.5 - 7.5 & # 37;, the firing temperature of the products was 1000 & # 176; C, isothermal holding for 1 hour. Studies have shown that the introduction of 2.5 & # 37; addition of fly ash to aluminosilicates ensures the leaching of heavy metals, sulphates and chlorides in accordance with the current regulation 2003/33 / EC. The density of such fired aluminosilicates is 1.8 g / cm ³, compressive strength 24MPa, water absorption 15.3 & # 37;, total open porosity 31 & # 37;, frost resistance at least 25 freeze and thaw cycles

The physicochemical properties of the carboxyl cation exchanger Tokem-200, sulfonic cation exchanger Tokem-140 and their selectivity with respect to the Ca ion ²⁺ under equilibrium conditions were investigated, the sol-gel method from solutions synthesized spherical biomaterials based on Tokem- 200. The framework of the material is represented by TiO ₂ -SiO ₂, and the inner part is filled with Ca ²⁺ oxide (sample TiO ₂ - SiO ₂ / CaO). Carboxyl cation exchanger Tokem-200 has the highest selectivity for Ca ²⁺ ions in contrast to Tokem-140, which makes it promising for the creation of biomaterials. It was found that the solutions are suitable for obtaining materials for up to 5 days.

The dependences for calculating the density of the heat flux into the environment from the outer surfaces of the enclosure of industrial furnaces: side walls, vault and hearth, obtained from the analysis of literature data, as well as as a result of mathematical modeling of a glass furnace, are presented. On the basis of a comparative analysis of these dependencies, performed for a glass furnace, recommendations were formulated for the selection and use of formulas for calculating the heat transfer coefficients from the outer surfaces of the fence in order to more adequately determine the heat balance of the furnaces.

Thermal analysis was used to study the behavior of various cobalt oxides (CoO, Co ₂ O ₃ and Co ₃ O ₄) when heated. At 200 - 850 & # 176; C Co ₂ O ₃ gradually passed into Co ₃ O ₄, which at & # 8776; 920 & # 176; С turned into CoO. The effect of mechanical treatment in a planetary and ball-ring mill on the yield of CoAl ₂ O ₄ spinel and the size of its crystallites at different temperatures is analyzed. The effect of MgO and ZnO additives on the size of pigment particles and color is estimated. The synthesized compounds were tested as pigments introduced into engobe, glaze, underglaze and overglaze paint using several ceramic masses

The results of a study of glasses and glass-ceramic materials synthesized in the R ₂ O (Na ₂ O, K ₂ O) -MgO-CaO system are presented. -Al ₂ O ₃ -SiO ₂ using granitoid screenings of the Mikashevichskoe deposit. Glass-ceramic materials have been obtained that, according to their performance characteristics, can be used as proppants in the oil and gas industry.