We studied the chemical and mineralogical compositions and determined the values of the limiting adsorption of methylene blue on samples of opal-cristobalite rocks. We found that the use of rocks with a high content of clay minerals is promising for water purification from high soluble organic compounds.
Technological features for container glass cullet cleaning from paper labels were considered. The analysis of some types of equipment operation, which help to realize such cleaning, was made. Constructive solutions of vibrating feeders to remove light impurities were suggested.
The influence of the structure and properties of acrylate monomers on the rheology and polymerization of suspensions containing partially stabilized zirconium dioxide, a dispersant and a photoinitiator as a ceramic filler is investigated. It has been shown that the use of the DISPERBYK 2013 additive makes it possible to obtain suspensions containing 1,6-hexanediol diacrylate, dipropylene glycol diacrylate and tripropylene glycol diacrylate with a viscosity value below 5 Pa?s at high (up to 41 vol. %) filling with TZ-3YS-E powder. The possibility of using the obtained suspensions for three-dimensional printing of high-density ceramic products with complex geometry has been established.
Today ceramic materials occupy more and more new niches of application. These include deep-water apparatuses for various purposes. For example, at present time oil production industry confronts the problem of discovering new oil and gas reserves, 40 % of which are connected with the development of ever-increasing sea depths that, in its turn, requires certain buoyancy of the submersibles to support the payload. The buoyancy can be provided either by a durable hull, or by using buoyant crafts (modules), or by both methods simultaneously. Due to high values of compressive strength, ceramics are considered as a promising material for operation at great depths, where hydrostatic pressure is significantly increased. The paper presents the results of analysis of domestic and foreign literature in the field of creation of hollow macrospheres based on ceramics for their use in modules of buoyancy of deep-water vehicles instead of syntactic foams with glass microspheres. It is shown that the most promising material is ceramics based on aluminum oxide. The results of ceramic spheres tests under the influence of pressures corresponding to the work of deep-water apparatus at different depths are presented. The analysis of the strength evaluation of ceramic macrospheres is given, which is necessary to assess their performance efficiency.
The results of research on the production of granular and block foam glass materials based on widespread highly siliceous rocks and technogenic waste are presented. The main attention of researchers is paid to the optimization of compositions and methods of obtaining materials that can be used as structural and heat-insulating, highly porous aggregates.
The possibility of solid-phase synthesis of multicomponent bismuth niobates and tantalates with pyrochlore-type structure (sp. gr. Fd-3m), containing atoms of transition 3d-elements in equimolar quantities is shown. The composition of this type pyrochlores can be described by stoichiometric formula Bi2Cr1/6Mn1/6Fe1/6Co1/6Ni1/6Cu1/6Ta(Nb)2O9 ± ?. A feature of synthesis of pyrochlores is a multi-stage high-temperature heat treatment process at a temperature of 650, 850, 950, 1050 °С for 60 hours. In the case of bismuth tantalate based pyrochlore, impurity phase of triclinic bismuth orthotantalate ?-BiTaO4 (sp. gr. P-1) is formed in trace amounts (? 8 mol.%). Complex pyrochlore based on bismuth niobate is characterized by a dense, low-porous microstructure in contrast to loose, porous tantalum pyrochlore with an average grain size of ? 2 µm. The unit cell parameter for pyrochlores containing niobium and tantalum is 10.4927(10.4922) ?, respectively.
The article considers two methods for the synthesis of composite precursors for the production of liquid-phase hydrogenation catalysts based on nickel and silica gel. A comparative analysis of synthesis methods depending on the method of preparation was carried out, and a study was made of the effect of mechanical activation on the textural properties of catalysts. Bulk density, particle porosity, specific surface area, total pore volume, and pore distribution along the radius were chosen as the main textural properties. For these purposes, X-ray phase analysis, scanning electron microscopy, and low-temperature nitrogen adsorption were used.
The purpose of this work was developing of protective technological coating for protection of heat-resistant nickel alloy with single-crystal structure ZHS30 during high-temperature homogenization. Based on characteristics of the alloy the synthesis of coatings was carried out in following directions: modification of known coatings in the system CaO–BaO–SiO2 by introducting refractory filler and organosilicon materials, research of two-layer coatings and synthesis of refractory frits in various silicate systems. The best properties of alloy ZHS30 are obtained using a coating based on a synthesized frit containing SiO2, B2O3, BaO, ZrO2. High efficiency of the protective action of the coating is ensured by the chemical composition of the frit which leads to the formation of structural groups [BO4] in the glass that participate in the formation of the glass lattice. Zirconium ions also participate in the construction of the structure and together with silicon and boron ions form a single boron-zirconium-silicon-oxygen framework of high degree of polymerization. The revealed liquation structure of the frit consists of two glass phases: the more easily low-melting matrix contains drop-like inhomogeneities distributed in it enriched of SiO2 which explains the steadiness and stability of the glass at operating temperatures.
The natural minerals of the Tebinbulak deposit, which are used as a thermal insulation material, have been studied, while their swelling coefficient depends on the size of the raw material and ranges from 3.47 to 7.67. The structure of the material has been studied by X-ray diffraction and infrared spectroscopy. The chemical composition has been determined by the microprobe method, and phase transformations during heating by differential scanning calorimetry. The obtained-information allowed us to conclude that this micaceousmineralis at the initial stage of metamorphism: disordered interlayer structure of phlogopite/vermiculite (hydrophlogopite). The information is important when discussing the influence of the structure of hydrosludes on the possibility and nature of their swelling during heating.
New glassy materials have been obtained in the ZnO–B2O3:CоO system. The physicochemical and spectral properties of zinc-borate glasses doped with cobalt have been studied in the composition range from 45 to 70 mas. % ZnO. The influence of the glass matrix on the coordination state of Co2+ ions is shown. Intense absorption bands in the visible region are attributed to the 4A2(F) ? 2A1(G), 4A2(F) ? 4T1(P) and 4A2(F) ? 2E(2G) transitions. The presence of an absorption band in the near-IR region (1.3 – 1.7 µm) due to the electronic transition 4A2(4F) ? 4T1(4F) of cobalt in the tetracoordinated state has been established.
