VOL 80, No. 8 (2007)

A computational and graphical analysis of the IR spectra of sodium borate and silicate as components of a glass batch obtained in an aqueous medium and probable impurities - boric and silicic acids was carried out. It was found that some bands, called critical, coincide or are closely located in the spectrum. Among them, the bands at 947 - 959, 1004 - 1005, 1079 - 1086, 1195 - 1200, 1450 - 1453, and 1686 - 1690 cm ^-1, which characterize the basic vibrations of atoms in bonds in structure-forming groups, are indistinguishable. by the wavenumber or by the intensity, because of which the identification of the formed phases is impossible. The concept of "conditionally distinguishable bands" in the spectra of compared substances has been introduced. The absolute degrees of difference in wave number and intensity, the order of band rejection and determination of the boundaries of the critical regions of the batch spectrum are considered. Tab. 3, ill. 3, bibliography: 12 titles.

The results of a study of the possibility of volumetric coloring of ceramic bricks by introducing manganese and iron ores, as well as metallurgical slags and sludge from electroplating industries, are presented. It was found that in order to achieve an expanded color range of products, it is advisable to pre-bleach low-melting clays with chalk or refractory clay, kaolin, impregnated with solutions of transition metal salts. The use of natural raw materials and soluble salts of 3d elements will significantly expand the raw material base, reduce the cost of ceramic products by replacing expensive materials, as well as combining the processes of pigment synthesis and firing products. Tab. 2, ill. 2, bibliography: 7 titles.

The process of nitride formation during the combustion of an iron-silicon alloy in gaseous nitrogen has been investigated. It was found that the synthesis of silicon nitride occurs at temperatures (2100 ° C), significantly higher than the temperature of the appearance of the liquid phase (1206 ° C). In the process of synthesis, silicon is in a liquid state in the form of an iron-silicon melt and in a gaseous state. Electron microscopic studies have shown that the growth of silicon nitride crystals is carried out by two mechanisms: vapor - liquid - crystal and crystallization from iron-silicon melt. The ratio of the contributions of these mechanisms to the structure formation process of silicon nitride is determined by the synthesis conditions. Il. 4, bibliography: 8 titles.

Copper-containing glazed glasses in the system B ₂ O ₃ - SiO ₂ - Al ₂ O _{3 < / sub> - CaO - CuO with a molar content of copper oxide from 5 to 25%, introduced during the synthesis of glasses. Glasses with a minimum content of 15% B 2 O 3 and 15 - 25% CuO crystallized during mining with the release of fine-needle crystals of CuO. However, all glasses form a good glaze coating when applied to ceramics at temperatures of 900 - 1000 ° C. In this case, CuO crystals completely dissolve in the melt. Il. 3, bibliography. 6 titles}

The effect of iron oxides on the physicochemical properties of ground enamels, which regulate the capillary movement of gas bubbles, has been studied. The velocities of the capillary motion of bubbles in the enamel melt were calculated by two mechanisms: thermodynamic and film overflow of Marangoni. In the approximation of the prevailing role of the thermodynamic mechanism, the duration of the release of gas bubbles from the enamel layer under the action of capillary force is determined. Il. 6, bibliography: 3 titles.

On the basis of a vacuum electric resistance furnace, an economical high-temperature installation for test fuses of quartz glass has been created. To modernize the melting chamber of a standard furnace, a heating unit with an operating temperature of up to 2200 ° C was developed and manufactured, consisting of a tungsten heater and molybdenum heat shields, which allows melting small-sized blocks of quartz glass. The upgraded furnace is used to assess the technological properties of natural quartz from different deposits. Il. 2.

The properties of molding mixtures based on kaolin containing modifying additives with different acid-base characteristics have been investigated. The introduction of liquid glass provides a significant improvement in the structural and mechanical properties of the system, as well as an increase in the mechanical strength of the finished granular sorbent. Preliminary modification of liquid glass with urea negatively affects the formability of kaolin masses. Treatment of kaolin with acetic acid and subsequent mixing of the mass with water glass reduces the suitability for extrusion; on the other hand, the volume of open pores of the absorber increases from 0.15 - 0.22 to 0.27 - 0.40 cm ³ / g. Tab. 1, ill. 3, bibliography: 9 titles.

The processes occurring in micro-grinding silicon carbide powders during the firing of abrasive products are considered, and the effect of the particle size distribution of powders on the properties of products is studied. The possibility of obtaining products of a given hardness using micropowders of various granulometric composition is shown. Tab. 4.

The technological schemes of processing a large-sized prism from blocking in gypsum and processing with free abrasives with the transition to individual fastening and the use of a bonded diamond tool in operations of coarse and fine grinding are considered. The results of improving the processing process with the transition to fine grinding operations from patch to plate tool and from felt to cloth PTS during polishing are presented. Tab. 3, ill. 3, bibliography: 5 titles.

Sintering of powders of finely dispersed chromium oxide has been investigated. It is shown that the production of dense non-porous samples is possible only by introducing an additive of titanium oxide and firing in a carbon-containing backfill. The optimal parameters of the technological process have been determined, the technological regulations for the process of manufacturing products from chromium oxide have been developed. The technology has been introduced into production. Tab. 5, bibliography: 3 titles.