The possibility of obtaining highly porous heat-insulating ceramic materials based on compositions of mineral binding components (clay and zeolite rock) with ash-containing waste from the combustion of solid fuel (ash microspheres) is considered. It has been established that the pore-forming effect of ash microspheres in mixtures with low-melting clay is due to both the porous macrostructure of the ash component (the presence of hollow spherical particles) and the nature of physicochemical processes in the "clay - ash microspheres" and "zeolite - ash microspheres" systems (the synthesis of anorthite and mullite proceeding with an increase in molar volume). The creation of highly porous ceramic structures from mixtures of ash microspheres with zeolite rock, in addition to the structural features of microspheres, is also due to the structural (channel) porosity of zeolite minerals. The established pore-forming effect of zeolite rock and ash microspheres made it possible to develop a method for preparing a semi-dry masses from these compositions and to propose a technological scheme for obtaining a highly porous ceramic brick. The use of zeolite rock as a binder in a mixture with ash microspheres in content up 60-95 wt%, modified with zeolite-lignosulfonate slip, makes it possible to obtain a highly efficient constraction and thermal insulation ceramic brick with a compressive strength of 18-30 MPa, volume weight 930-1100 kg/m3 and thermal conductivity 0.22-0.31 W/m.K at a firing temperature of 950-1000 degrees C.

A detailed study of the MgO-CO2-H2O system allows creating new inorganic binders. The present research is focused on the process of structure formation during hydration and curing of magnesia composition from active magnesium oxide and magnesium bicarbonate solution. Magnesium hydroxide and magnesium hydrocarbonates, basically hydromagnesite and dypingite are the products of MgO interaction with solution of magnesium bicarbonate Mg(HCO3)2. This was established by means of complex thermal analysis using thermogravimetry (TG), differential scanning calorimetry (DSC), mass spectrometry (MS), and electron microscopy. These methods allowed us to define the influence of the curing environment of magnesia composition. Results show that processes of hydration and curing of composition of magnesium oxide with magnesium bicarbonate solution proceed most effectively in water conditions at the course of cyclic reactions of magnesium hydrocarbonate formation. The magnesia composition transforms magnesia cement into the state of hydraulic magnesia cement.

The possibility of using natural raw materials with the structural porosity of the rock-forming mineral (zeolite rocks) to obtain ceramic bricks was investigated. It was determined that the effectiveness of zeolite additives is determined by their dispersion, content in the mass, type of clay raw materials, as well as the temperature conditions of processing of ceramic materials. The addition of zeolite rock in the amount of 10–30% to mixtures with highly drying-sensitive clay or clay with high natural humidity acts as a moisture extractor and non-plastic additive. This additives reduces the index of drying sensitivity by a factor of 3.5–4 without impairing the material cohesiveness. It has favourable effects on the crack resistance of green products during drying and enables automated, reject-free loading of the dry products into a kiln. The improvement of the drying properties of clay raw materials is achieved by transferring part of the free water introduced from the flooded clay into a bound state by entering it into the channel-frame space of zeolite minerals. The established effect of zeolite rocks allowed to develop a method for controlling the moulding and drying properties of clays with high natural humidity and (or) with high sensitivity to drying, as well as process flow sheet for ceramic bricks from clay-zeolite compositions by the plastic method.

The influence of the small addition of topaz on the processes of mineral formation in the "mullite-cordierite" system with a variable ratio of cordierite and mullite has been investigated. For this purpose, a series of experiments with different compositions of the initial mixtures, that is, with predominance of cordierite over mullite (KM mixtures) and predominance of mullite over cordierite (MK mixtures), has been performed. The addition of topaz in the form of topaz concentrate has been introduced in the amount of 1% by the weight of the investigated mixtures. The samples have been fired at various temperatures, that is, samples from KM mixtures (at a temperature of 1100-1300 degrees C) and samples from MK mixtures (at a temperature of 1400-1550 degrees C. The activating effect of topaz on mineral formation and sintering processes is determined by complex influence of fluoride products of topaz thermal decomposition. These reactively gaseous fluorides partially activate the solid phase mass transfer processes and then reduce the viscosity of high-temperature melt formed during firing that intensifies the processes of ceramic matrix consolidation. Porous polycrystalline cordierite mullite corundum ceramics from the KM mixtures, which contains 70%-87% cordierite, 3%-12% mullite, and 4%-11% corundum with water absorption of 3.5%-8% and bulk density of 2.10%-2.12 g/cm(3) at the firing temperature of 1300 degrees C, has been developed. Mullite ceramics with notably corundum content (not more than 8%) from the MK mixtures with various density degrees at the firing temperature of 1500-1550 degrees C, porous ceramics with water absorption of 3%-11%, and dense ceramics with water absorption of less than 1% have been produced.

In this study, the complex influence of the preliminary calcination temperature of refractory clay raw materials and mineralizing oxide additives on phase formation, microstructure and properties of aluminosilicate proppants was researched. The morphology structure and phase composition of specimens were investigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results show that the effectiveness on the addition of 3d-transition element oxides (Fe2O3 and MnO2) and alkaline and alkaline earth oxides (Na2O, MgO, CaO) and B2O3 to the sintering process of samples based on kaolin depends on the temperature of preliminary kaolin calcination (900-1100 degrees C) and temperature sample sintering (1350-1450 degrees C). Based on the effectiveness of the influence on aluminosilicate ceramic sintering at the temperature range of 1400-1450 degrees C, the recommended additives can be sequentially arranged as follows: Fe2O3 > MgO > MnO2 > Na2O > B2O3 > CaO. The thermal activity scheme for each group of mineralizer additives depending on the temperature conditions of the consolidation process has been proposed in this study. The use of mineralizing additives with kaolin calcined at a temperature range of 980-1100 degrees C produces lightweight aluminosilicate proppants with bulk density of up to 1.50 g/cm(3) at sintering calcination of 1400-1450 degrees C, which can endure destructive pressures up to 52 MPa.

A fractional (rational) chemical analytical method is proposed by which the material composition of clay rocks can be quantified and the clay-forming minerals present can be characterised. Subjecting raw clay to this procedure allows for the determination of the chemical composition of its fine-grained fraction, the amount and composition of exchangeable cations, water-soluble salts, carbonates and colloidal minerals, and the amount of amorphous silica and free quartz. A new, effective method is proposed for the qualitative and quantitative evaluation of the amorphous component in clays. This involves extracting colloids by treating the clay fractions with Tamm's reagent, a buffer solution of oxalic acid and ammonium oxalate with a pH of 3.25. Additionally, through calculations based on the results of chemical analyses, the illite content (derived from the content of non-exchangeable potassium oxide) and the chemical composition of the clay residue are determined. This enables the rock-forming clay mineral to be characterised and its structural chemical formula to be determined. This allows prediction of the physico-chemical and technological properties of the clay.

It was established that pore-forming effect of both fuel ash and ashy microspheres on clay rocks compounds is caused both by the structural features (the presence of the spherical shaped hollow particles), the ashy component composition, and the physical and chemical processes taking place in the clay ash and clay ashy microspheres systems, the latter processes preventing the shrinkage on sintering (owing to the anorthite and mullite synthesis occurring with molar volume increasing). Ill. 6. Ref. 14. Tab. 2.

This work contains results of investigation of obtaining high thermally conductive ceramics from commercial powders of aluminum nitride and yttrium oxide by the method of monoaxial compaction of granulate. The principal scheme of preparation is proposed and technological properties of granulate are defined. Compaction conditions for simple items to use as heat removal in microelectronics and power electrical engineering have been established. Investigations of thermophysical properties of obtained ceramics and its structure by the XRD and SEM methods have been carried out. Ceramics with thermal conductivity from 172 to 174 W/m·K has been obtained as result of this work.

The paper presents a study of structure formation during the hardening of a new water resistant hydraulic magnesium cement. Improvement of water resistance and the manifestation of hydraulic properties in magnesium cement are associated with the use of a fundamentally new mixing liquid involving a magnesium bicarbonate solution. Use of this solution makes possible for the magnesium composition to harden not only in air, but also in water. The Coefficient of resistance is 1.0–1.8. When mixing the magnesium cement with an aqueous solution of magnesium bicarbonate, the main products of hardening are magnesium hydroxide and magnesium hydrocarbonates. The increase of the hydrocarbon phase contributes to the strengthening characteristics of magnesia compositions. Magnesium hydrocarbonates are insoluble in water, which provides the increased water resistance of magnesia compositions and the opportunity to harden and gain strength in water.

The research results of the hydrolysis processes of aluminum nitride powders received by the SVS method in dependence on humidity of the storage environment, and grain size distribution are presented in this work. Oxidation kinetics was estimated by means of Xray Diffraction (XRD) and scanning electron microscopy (SEM). The induction period of the hydrolysis process for various powders, its dependence on powder dispersion and thickness of the oxide layer on surface of particles have been defined.

This work contains results of investigation of obtaining high thermally conductive ceramics from commercial powders of aluminum nitride and yttrium oxide by the method of monoaxial compaction of granulate. The principal scheme of preparation is proposed and technological properties of granulate are defined. Compaction conditions for simple items to use as heat removal in microelectronics and power electrical engineering have been established. Investigations of thermophysical properties of obtained ceramics and its structure by the XRD and SEM methods have been carried out. Ceramics with thermal conductivity from 172 to 174 W/m.K has been obtained as result of this work.

It is determined that the pore-forming effect exhibited by ash and ash microspheres in compositions with clayey rocks is due not only to certain structural features (the presence of spherical hollow particles) and the makeup of the ash components (the presence of residual fuel in the ash) but also to physico-chemical processes (the synthesis of anorthite and mullite) which take place in clay – ash-and-clay – ash- microsphere systems and prevent shrinkage during sintering.

The paper presents the results of the survey reflect the relationship of properties and a process for producing aluminum nitride industrial powders on their reaction activity. Been ascertained he quantitative change in the chemical and phase composition of powders by reacting with moisture in the air and natural moisture. The composition of the products of the interaction of aluminum nitride powders with moisture in the air was determined.

Представлены результаты исследований отражающих взаимосвязь свойств и способа получения про-мышленных порошков нитрида алюминия на их реакционную активность. Установлено количественное изменение химического и фазового состава порошков при взаимодействии с влагой воздуха при естествен-ной и повышенной влажности. Определен состав продуктов взаимодействия порошков нитрида алюминия с влагой воздуха.Ключевые слова: нитрид алюминия, оксид алюминия, гидролиз, степень превращения

Thermoplastic slip from commercial powders of yttrium nitride and yttrium oxide. The scheme of making the slip is proposed, the casting properties are determined. The influence of sintering additives dispersion and molding conditions (pressure, temperature) on slip properties is researched.

This work contains results of investigation of obtaining high thermally conductive ceramics from commercial powders of aluminum nitride and yttrium oxide by the method of monoaxial compaction of granulate. The principal scheme of preparation is proposed and technological properties of granulate are defined. Compaction conditions for simple items to use as heat removal in microelectronics and power electrical engineering have been established. Investigations of thermophysical properties of obtained ceramics and its structure by the XRD and SEM methods have been carried out. Ceramics with thermal conductivity from 172 to 174 W/m·K has been obtained as result of these work.

Проведен анализ пригодности природного сырья для получения кислотостойкой керамики. Объектом исследования является кислотоупорная керамика на основе глинистого сырья уральского региона в композициях с нетрадиционными сырьевыми добавками. В качестве основного компонента была выбрана глина Берлинского (Южноуральского) месторождения Челябинской области. Исследованы основные характеристики глинистого сырья, такие как химический, гранулометрический и минералогический составы, поведение глины при сушке и обжиге. В качестве добавки, снижающей температуру спекания, не ухудшая при этом кислотостойкость материала, использовали горную породу – фельзит. В процессе работы был проведен ряд исследований по определению физико-механических характеристик разрабатываемых материалов. В результате была установлена возможность получения кислотоупорной керамики на основе составов «глина–фельзит», отвечающая требованиям ГОСТ.

The article describes the research work on the influence of a way of obtaining powders of aluminum nitride and powder purity on the thermophysical properties of the produced ceramics. The ceramics was obtained from aluminum nitride with high heat conductivity and relative density of more than 98 %, which is suitable for being used as heat-removing substrates for the production of various products in radio electronics.