Vol 75, No 9-10 (2019)

The current status of theoretical research on close-packed systems of hard spheres is reviewed. The basic models of regular and random close-packings of hard spheres are described. Examples are presented of the application of modeling of the close packing of hard spheres for solving applied problems in the development of promising materials made from ceramics, including refractories.

The chemical-mineralogical compositions and physical-chemical characteristics of Yazyavanskoe dune sands as well as the suitability of these sands for use together with other raw materials available in Uzbekistan in optimizing the compositions of ceramic facing tiles were studied. It was found that the weight content of dune sand and the composition of the ceramic body of facing tile in ternary and quaternary compositions must not exceed 45 and 25%, respectively. The optimal technological parameters for obtaining ceramic tiles using dune sands, meeting GOST 6141–91 specifications, are determined.

The properties and graphical plots of the properties of bismuth-borate glasses in a wide range of compositions—20 to 80 mol.% Bi₂O₃ —are presented. In multi-bismuth glasses both the boron and bismuth ions are found in two coordination states: B³⁺, B⁴⁺ and Bi³⁺, Bi⁶⁺. The [BiO₃] groups play the role of a conventional glass former but manifest weakly in the IR spectra.

The types and function of foam glass are examined as a function of the employed foaming agents. Mixes with different granulometric composition of the batch were developed and subjected to heat-treatment. The influence of the fractional composition of the foam-glass batch on the density and volume of the foam glass and foam-glass materials was studied.

Complex studies of glass formation were conducted and the properties of glasses in the system of materials quartz sand – colemanite – soda determined. It is established that the multicomponent raw-material colemanite can be used in the production of different types of borosilicate glass and glass articles with different compositions. An assessment of the prospects and efficacy of its use is given.

The factors influencing the thermal conductivity of SiC-based ceramic composite materials obtained by the spark plasma sintering technology with relative density 99% and B₄C, AlN, Si₃N₄, Y₂O₃, Al₂O₃, and HfB₂ as additives are examined. The thermophysical properties were determined in the temperature range 20 – 1300°C: specific heat, thermal diffusivity, and thermal conductivity of composites. The thermal diffusivity and specific heat were measured by the laser-spark method. The measurements of specific heat are supplemented by measurements performed with a DSC and adiabatic calorimeter. The thermal conductivity is calculated using data on the thermal diffusivity, specific heat, and density.

The composition and a method of production are proposed for high-porosity materials in low-temperature foaming of liquid glass and ash-slag material from burning of combustible shales used as fill and consumable additives. It is shown that keramzit based on liquid glass must be cooled at the rate 60 K/min, because a porous material with high structural quality factor and with high FeO content is formed at this cooling rate.

The results of IR-studies of chemically modified zeolitic raw-material from the Vanginskoe deposit in the Amur region are presented. It is shown that hydrochloric acid brings about decationization and de-aluminization. It is established that in the process of modification the chemical composition changes and the crystallinity decreases.

Different designs of vibratory granulators of glass melt are examined. The primary advantages and disadvantages of such equipment used for recycling glass wastes are presented. A design is proposed for a reversing vibratory granulator and a scheme is proposed for using it in a recycling line for colored and colorless cullet formed in the production of glass containers with coloring of the glass melt in the feed channel.

The fourth author’s name should read B. M. Gol’tsman.