The paper presents the results of a comprehensive study of the thermophysical properties of 21 samples of skull and refractory lining collected after blowing out blast furnace No. 6 (EVRAZ NTMK). The open porosity, apparent density, melting point, thermal coefficient of linear expansion (TCLE), thermal diffusivity, and heat capacity of the samples are determined, and their thermal conductivity is calculated

By means of a calculation, the expediency of fan loading of bunkers with powdery bulk material is shown. The design of an annular loading device using the Coanda effect to reduce dust generation is proposed. The rational design and technological parameters of the developed device have been determined numerically and experimentally.

The behavior of a heat-protective ceramic composite material based on ZrO2 fibers in a concentrated solar energy flux under conditions of a strongly nonequilibrium temperature and light field is demonstrated. A change in its structure and morphology depending on the heat treatment temperature is displayed. During an experiment the maximum surface temperature of a specimen based on ZrO2 fibers reaches

Results of studying preparation of new compositions of chemically resistant refractory composite materials based on Klyuchev Concentration Plant waste products of fused alumina grades PPG-50TP and PPG-65TP are presented. Good chemical resistance, fire resistance, mechanical strength, hardness, and wear resistance make it possible to use them for manufacturing refractory products, concretes, and mixes

The possibility of using fly ash from thermal power plants to prepare fused mullite powder with subsequent use as a filler for aluminosilicate refractories is investigated. Introduction of orthophosphoric acid as a binder to a raw material charge provides a reduction in firing temperature of fireclay refractories by 150 – 200°C, which is an important factor in the contemporary organization of production

The linear regression analysis was used to perform a comparative assessment of the mathematical description of the experimental compaction curves by the new basic equation and the empirical compaction equations proposed by Balshin, Heckel, Kawakita, Panelli–Filho, and Ge. The studies were conducted on a specially compiled representative sample of the mining and metallurgical complex materials, divided

Various mixtures of initial Ti/Si/C, Ti/Si/TiC, Ti/SiC/C, Ti/SiC/TiC, Ti/TiSi2/TiC, and TiH2/SiC/C powders were used to synthesize Ti3SiC2 by sintering at 1300 and 1400°C for 1 – 5 h. Ti/Si/TiC and Ti/TiSi2/TiC powders were best for synthesizing Ti3SiC2. The amount of synthesized Ti3SiC2 reached 98.3 and 90.3 vol% at a sintering temperature of 1400°C for 1 h. Ti3SiC2 was synthesized and grew in the

We establish the main regularities of the stressed state of the surface layer of ground Si3N4–TiC ceramics under the action of combined loads. We also reveal specific features of the formation of structurally inhomogeneous stresses and microstructural stress concentrators affecting the structure of the ceramics as a result of the formation of discontinuities.

The effects of mixtures of Ni–Ta and Ni–Zr powders combined with sintered solid solution TaB2 –NbC during spark-plasma sintering of compositions at a pressing loading of 60 MPa in the range 1200 – 1600°C on the phase composition, percent content of Ti, Ta, and Zr in the sialon; microstructure; grain sizes of crystalline phases; relative density; linear shrinkage; physical-mechanical properties; linear

We present the results from a chemical analysis of dust samples collected in a sinter shop. Grates with dust suction in the immediate vicinity of the hot grate are proposed for dust reduction in industrial premises. The work performed in this paper supports improvement of screen reliability, reduces the negative pressure differential, and ultimately reduces energy costs by preventing the channel openings

Effectiveness of a new stage equation for identifying and analyzing individual stages of compaction was assessed. Results revealed that the newly developed equation describes correctly and accurately the experimental compaction curves, which considers the periodic nature of the process and enables the determination of characteristic transition points between stages, whereas. the determination coefficient

With the help of the main concepts of computer engineering, we study the thermal and stressed state of the surface layer of ground Si3N4–TiC ceramics of four systems subjected to the action of heat flows. We analyze the regularities of temperature and stress distributions in six selected surfaces of the surface layer. We also determine specific features of formation of structural inhomogeneities of

A fundamental difference between the grain size composition of cement-free refractory concretes (CFRC) from low- and ultra-low-cement concretes is presence within their composition of up to 2 – 3 % nanoparticles (<0.1 μm) that determine increased reactivity. During selection of the optimum CFRC grain size composition in order to achieve the densest particle packing there is often use of “ideal curves”

The majority of refractory materials and raw minerals used for their production are crystalline substances. X-ray diffraction techniques can be used successfully for qualitative and quantitative determination of their mineral composition and for analysis of the technologically significant structural features that are most important in a production process. Examples are considered for the main types

The effectiveness of refractory products made of new improved refractory materials is achieved if, during their installation and repair, a masonry composition is used, the properties of which provide a similar level of heat resistance in the aggressive environment of the electrolyzer as the material of the products. The article establishes the optimal component composition of the masonry mixture for

Results are provided for studies concerning the choice of parameters and optimization of plasma spraying regimes (plasmatron arc current strength is 170 – 175 A, voltage is 165 – 170 V, gas consumption is 2.5 – 2.7 m3/h, sprayed material consumption is 10 g/sec, spraying distance is 140 – 160 mm) and subsequent plasma fusion (plasma arc current is 190 – 200 A, voltage is 165 – 170 V, gas consumption

The separation curves for gravitational separation processes have the property of affinity. This means that with a certain transformation of the coordinate axes, all experimental values of fractional extraction form a single curve in these coordinates. The ordinate values for obtaining such universal curves are called similarity criteria for separation processes. Similarity criteria have been determined

Samples of mineral hydraulic binder and artificial stone based on such binder were obtained from granulated blast furnace slag and Portland cement M500 using vortex electromagnetic homogenization. The following physico-chemical characteristics of mineral powders have been investigated: phase and chemical composition, specific surface area, particle size distribution, mechanical properties of artificial

Ceramic plates with dimensions of 90 × 40 × 7 mm and a density of 3.41 g/cm3 were obtained by the method of free SHS-compression. The resulting plates consist of three phases: aluminum oxide, titanium diboride, and mullite. The plates have a composite structure: a matrix based on Al2O3 with titanium diboride particles distributed in it. Also, in the structure of the obtained plates, whiskers of titanium

The thermal shock resistance of alumina ceramics with a fine-crystalline structure (crystal size 5 – 40 μm) and with a layered-granular structure, as well as t-ZrO2–Cr(40 vol. %) cermet, was studied. Layered-granular ceramics consisted of randomly oriented layered granules, including alternating dense fine-crystalline layers and porous layers made of corundum microballoons. The cermet structure is

The paper presents the results of analytical and experimental studies of the thermal zones in the working space of the modules of an electric pouring furnace. To increase the production rate and reduce the energy content of the work process, the local granular media flows were distributed between such zones depending on their heating. The modular-pouring furnace, equipped with plate accelerators located

The theory of gravity classification processes is usually based on the regularities of the behavior of isolated particles in a flow. This approach has been justly criticized since long ago, since it is impossible to interpret the phenomena observed in actual processes (incomplete separation, affinity of curves, products contamination, etc.) from this standpoint. Only after providing an insight into

Information on the temperature coefficient of linear expansion (TCLE) of materials based on silicon carbide is presented. It is shown that the different polytypes 3C (cubic modification) and 4H and 6H (hexagonal modifications) are characterized by different thermal expansions, the difference between the values of which increases with increasing temperature. The TCLEs of reaction-sintered, liquid-phase-sintered

Six variants of direct and reverse coprecipitation of a mixture of salts by an aqueous solution of ammonia or an ammonia buffer solution with pH 9.5 are considered to optimize the technological scheme for the synthesis of zirconium dioxide nanopowders stabilized with 2.5 mol.% yttrium oxide. The influence of the storage time of the mixture of salt solutions before precipitation on the phase and chemical

We consider the process of multistage technological recirculation of aspiration air into transfer chutes, i.e., the return of aspirated air from the shelters of the technological equipment back to the technological process with an aim to reduce energy losses by creating aerodynamic drag in the path of motion of ejection air and maintaining the required values of thermal parameters in the equipment

We study the influence of temperature, stresses, and resistivity of a foam masses on the intensity of moisture removal. We select three zones of changes in the electric resistivity. The distribution of the pressure field is connected with the filtration of moisture in capillary-porous materials. For the insufficient structural strength of interporous partitions and sharp changes in temperature, we

The article investigates the influence of the reduction modes of hollow nickel oxide microspheres synthesized by the pyrolysis of ultrasonic aerosols on the ratio of the oxide and metallic forms of nickel in their structure. The synthesis of microspheres from an aerosol of an aqueous solution of nickel nitrate was carried out; their composition and morphology were studied. The reduction of microspheres

The paper presents the results of testing a heat-protective material based on Al2O3 and SiO2 fibers under exposure to a concentrated solar energy flux and highly non-uniform thermal and light field conditions. Avariation in the material structure and morphology depending on the heat treatment temperature is shown. The material retains its properties during extended exposure to temperatures of 1,600

The results of studies of the effect of alumina nanofiber on the physical and mechanical characteristics of refractory concrete NPC-21AC are presented. It is shown that the use of nanofibers increases the flexural strength by 50 % and compressive strength by 30% with a 15% decrease in Young’s modulus. An increase in physical and mechanical characteristics leads to a 54 – 72% increase in thermal resistance

We studied the service conditions for the lining of the Waelz kilns at the Chelyabinsk Electrolytic Zinc Plant and the Ust’ Kamenogorsk Lead and Zinc Plant, and identified the primary sources of wear on the refractories. Refractory wear inWaelz kilns primarily occurs via a chemical reaction between the refractories and the components of the charge, which is then followed by abrasive wear. PKhPP [periclase-chromite

Chemical modification of tantalum carbide powders by siliciding of them in an SiO-gas atmosphere at 1400°C and sintering of the chemically modified tantalum carbide powders by hot pressing at 1700°C and 25 MPa are investigated. The phase composition, microstructural features, and strength characteristics of the obtained high-density ceramics based on chemically modified tantalum carbide powders are

Data are provided for preparing fuzed and fuzed stabilized zirconia from baddeleyite and synthetic zirconia in induction, plasma, and electric arc furnaces. Results are discussed and prospects for carbothermal preparation of zirconium dioxide from zircon in an electric arc furnace are demonstrated. A favorable effect of oxidation melting in an electric arc furnace on quality and the process of fuzed

On the basis of the main concepts of computer engineering, we study the stressed state of the surface layer of ground Si3N4–TiC ceramics subjected to the action of force loads. The formation of microstructural stress concentrators at the point of application of concentrated forces is discovered. These concentrators lead to changes in the structure of the ceramics due to the formation of discontinuities

The main properties, purpose, and application of building material binders in mine workings are provided. Supply of binders and aggregates to mine workings is performed in soft containers, and unloading of flexible containers is carried out using pneumatic chamber unloaders. A pneumatic unloader is developed for unloading and feeding material to its destination, including lifting. It is proposed to

In this paper, the base of the charge used for the production of porous materials is made up of industrial waste generated by machine-building factories, which consists of metal oxides (oxide scale of alloy steel) and metal powders. Therefore, it is important to study the creation of new porous permeable cermet materials (PPCMs) with partial or complete addition of the metal and metal oxide powders

Composite binders with an SiC content from 10 to 40% are prepared on the basis of high-alumina chamotte and silicon carbide powder previously dispersed in water. Ceramic concretes are prepared based on highly concentrated ceramic binder suspensions (HCBS) and mullite polydispersed filler by vibration casting and their properties are studied. Specimens containing 15% SiC have maximum strength in compression

The effect of a marshalite additive on nitriding of a complex ferrosilicoaluminum (FSA) ferroalloy to produce a sialon-based composite by self-propagating high-temperature synthesis is studied. The phase composition of the combustion products is revealed by changing the percentage of the marshalite additive in the starting reaction mixture. The optimal ratio of the marshalite additive to the initial

The exceptional efficiency of combining clay additives with introduction of thinning additives of a complex organomineral thinner (COMT) is observed. Values of 14 – 15% initial porosity of compacted high-alumina ceramic concrete with a compaction pressure of 30 MPa are achieved. Depending on mix composition and clay additive content with a comparable moisture content during static compaction material

The article shows the possibility of using the method of measuring the sound absorption coefficient α to predict the heat resistance and residual life of heat-resistant materials using the example of heat-resistant concrete of three different compositions (without additives, with a plasticizer, with a micro-filler and a combined plasticizer). The critical value of α, corresponding to a significant

The main elements of the working surface of the diamond wheel after grinding Al2O3–TiC-ceramics are revealed and their parameters are investigated. Using the developed technique, topographic maps, projections of grains, and transverse and integral profiles for the selected sections of the working surface of the diamond wheel were constructed. A method is proposed for predicting the quality of a polished

Combined refractory materials due to their physical and mechanical properties and high stability have been widely used in recent years in metallurgical assemblies with sudden changes in temperature regime, as well as during prolonged downtime or temporary shutdown. Silica refractory can be prepared from clay, chamotte with the addition of silicon production waste (microsilica), as well as with addition

The effects of powder mixtures of W–Mo and Zr–Ti combined with sintered solid solution TiC–ZrC during spark plasma sintering of compositions at a pressing load of 60 MPa in the range 1200 – 1600°C on the phase composition, microstructure, grain sizes of crystalline phases, relative density, linear shrinkage, physical-mechanical properties, and linear correlation of elasticity modulus and fracture toughness

Results are provided for a comprehensive study of bentonite clay of the North-Dzhamansai deposit of Karakalpakstan in order to prepare ceramic heat insulation materials. According to chemical-mineral and fractional compositions, as well as physicochemical characteristics of bentonite clay, the possibility is established of its use in the production of ceramic heat insulation materials for various purposes

The results of investigation of the rate of gas flow and powder particles flying at plasma-jet hard-facing by a constricted arc in gas powder protective media are presented. A new method of welding bath protection by a gas powder flow is proposed, which makes it possible to reduce the argon consumption by 50 – 60%, as well as to reduce plasmatron mass-dimensional characteristics, while abandoning the

The efficiency of insignificant additions of clay and kaolin in relation to the production of molded and unmolded ceramic concretes, based on the use of HCBS of silica, aluminosilicate, high-alumina and corundum compositions, is shown. These additions can be made both as part of HCBS and in molding systems in the manufacture of ceramic concrete. Clay additives are especially effective in the manufacture

Addition of various reinforcements was studied in an attempt to produce a TiC–Al2O3 composite with high density, homogeneous microstructure, and outstanding mechanical properties for use in aggressive media using self-propagating high-temperature synthesis (SHS). Ductile Ni-metal powder (5 – 20 wt.%) and Al2O3 and ZrO2 (1 mole fraction) dilutions with and without Ni addition were introduced into TiC–Al2O3

The results of force, thermal, and combined analyses of the stress-strain states of the surface layers of Al2O3–TiC ground ceramics are systematized. The relationships obtained as a result of the systematic analysis serve as a basis for the refinement of the physical models of fracture of the products made of Al2O3–TiC ceramics in the course of operation.

The concept of creating electrical insulating ceramic materials and objects from powder systems represented by oxide and nonoxide chemical compounds is formulated; a program document for materials science and technological logistics of physical and chemical transformation of technogenic mineral raw materials into electrical materials and products for various scientific, practical, and specific engineering

The use of nanomaterials for the implementation of a new set of functional properties has no alternative when creating refractory composite materials. Fine-dispersed Al2O3 is a necessary component of special high-quality cements, heat-resistant inert refractories and abrasive materials. Equations are obtained for the average values of the Euler and Reynolds criteria, the relaxation time of liquid droplets

To the article “Thermodynamic Modeling of Chemical and Phase Transformations in a Waelz Process-Slag – Carbon System,” by A. S. Kolesnikov, G. S. Kenzhibaeva, N. E. Botabaev, A. N. Kutzhanova, G. M. Iztleuov, A. Zh. Suigenbaeva, Kh. A. Ashirbekov, and O. G. Kolesnikova, Vol. 61, No. 3, pp. 289-292, September, 2020.

The results of research on obtaining a new composition of chemically resistant, refractory concrete mixture are presented. The basis of the resulting mass is production waste, which is a slag of electrothermal reduction of niobium pentoxide — crushed and purified fused alumina — electrocorundum, ferrosilicon slag, ferrochrome slag, refractory aluminosilicate mortar and refractory clay. High chemical

Strong lightweight refractory materials were obtained with an apparent density ranging from 1060 to 1280 kg/m3 based on clay and nonplastic aluminosilicate raw materials with the introduction of a low-temperature burn-out additive of expanded polystyrene (EPS). The average pore size of the ceramics is 0.05 – 0.35 mm. The optimal fractional composition of the charge and the content of EPS were determined

In this paper, friction and wear properties of the friction composite materials obtained using a powder metallurgy method were analyzed. Tribotechnical properties of the material samples were studied on a MMW-1 vertical system using a pin-on-disc mechanism. An Amscope optical microscope was used to characterize the wear surface of the samples.

A method for shotcreting steel-pouring ladles under PAO MMK oxygen-converter workshop (OCW) conditions is described. Tests are conducted in the period 2018 – 2020. Results of the work performed are identification of operating parameters that affect wear of the working layer of the lining of steel-pouring ladles beneath the shotcrete layer, prospects for maintaining the lining by shotcreting in order

This article describes the process of firing aluminum nitride substrates, which is a process that occurs under its characteristic conditions: high temperatures of over 1800°C and a reducing environment. This article also presents the fact that high quality substrates having desirable properties such as high thermal conductivity and parallelism between layers can be achieved. This article also describes

As a result of thermal expansion of the gas phase of a foam mass playing the role of compacting component in a closed volume, we observe the appearance of excess internal pressure accompanied by the formation of the fields of pressure, temperature, and moisture content. The partial flows of liquid caused by these fields are directed from the center toward the perforated walls of the form and go further

Heat-insulating mixtures developed on the basis of local raw materials are considered. Their properties are determined using Russian-made installations and their application at domestic metallurgical enterprises.

Results are given for synthesis of AlN–Al2O3–Y2O3 composites in a combustion regime in an industrial reactor. The effect of synthesis temperature on formation of the microstructure, phase composition, and impurity oxygen content dissolved in the crystal lattice of aluminum nitride is studied. The optimum synthesis temperature is determined. Experimental batches of composite powders are produced for

This article presents a universal version of a booster device for lifting a carrying medium in the presence of lump materials, and calculation equations for determining the dependence of the movement speed of a three-phase medium in a slurry pipeline with a turbo-vortex slurry movement, as well as for determining the additional volume of air supplied through the booster device to the slurry pipeline

The chemical and phase compositions of a ceramic material (plinth) aged more than 1,000 years that was used to construct the fortress wall were studied. Elemental analyses determined that the material had an increased carbon content of 9.50%, indicating that fuel was introduced into the raw material. This not only increased the porosity of the products but also contributed to uniform sintering of the