Rational Technological Parameters Research Articles

Мaterial composition and thermal properties of chrysotile asbestos enrichment tailings of the Kiembaevsky deposit

The article discusses the issues of carbon removal in a circulating vacuum unit. It is shown that in order to achieve an ultra-low carbon content (less than 0.002 %), it is necessary to take into account the wear of the lining of steel ladles. When replacing periclase-carbon products in the walls and bottom of the steel ladle with carbon-freeones, carbon intake into the melt can be significantly reduced. Additionally, rational technological parameters of steel processing in a circulating vacuum unit were determined.

Revealing the effect of hydrothermal processing of legumes on the accumulation of dry matter in aquafaba

Legumes are an affordable source of vegetable protein, fiber, and vitamins, and due to their high nutritional and biological value, they are widely used in the nutrition of various categories of consumers. The main methods of processing legumes include hydromechanical and hydrothermal treatment, which is aimed at achieving culinary readiness of boiled legumes. Studying the parameters of the specified technological process for the accumulation of dry substances in aquafaba could make it possible to influence the composition and properties of this liquid, which would provide opportunities for its use in the food industry. The influence of hydrothermal processing of leguminous grains on the accumulation of dry matter in aquafaba, as well as the kinetics of moisture content of various types of leguminous grains, have been experimentally investigated, which made it possible to determine the rational parameters of hydromechanical and hydrothermal processing of chickpeas, beans, peas, lentils, with the preparation of boiled leguminous grains and aquafaba. It was determined that during hydromechanical processing intensive moisture absorption occurs in the first hours and reaches up to 80 % of the initial mass, after which the intensity of water absorption decreases somewhat. Rational technological parameters of hydrothermal processing of leguminous grains by two methods, basic (cooking at a temperature of 99±1 °С) and under pressure (cooking in a pressure cooker at a temperature of 120±1 °С) were established in the relationship "achieving the readiness of legumes – the content of dry substances in aquafaba". The use of the above-mentioned techniques for hydrothermal processing of leguminous grains make it possible to obtain the content of dry substances in aquafaba in the range of 2.8–4.8 % for cooking by the main technique and 3.9–7.0 % under pressure cooking conditions. To understand the processes regarding the influence of hydrothermal processing of legume grains on the accumulation of dry substances, the Peleg model was used. The experimental data could be used to substantiate parameters for the technological process to produce foods based on legumes

Enrichment of functional drinks using grape pomace extracts, analysis of physicochemical indicators

A large amount of residues called secondary raw materials are formed during grape processing, the majority of which are pomace-containing seeds. Pomace is obtained by crushing grapes with subsequent juice separation and appears as a mass consisting of skin, seeds, as well as stalk and comb residues. When compared to the control, the amount of skin in the fermented pomace increased 15 %, while the amount of seeds decreased by about 50 %. The objects of research is juice, wine materials, functional drinks, technological methods and means. The problem is that the samples of juice and dark wine prepared by the "White method" are not provided with a sufficient amount of extract substances, especially compounds that provide functionality. The results of the experiment show that adding 25–30 % wine-alcohol extract of marc to the wine material obtained by the “white method” from the Bayanshira grape variety, and adding 25–30 % alcohol-juice extract to the juice obtained from its own stream, give a positive result. Compared to the control, in the prepared functional wine samples the content of phenolic compounds increased by 100 mg/dm3, and there was also an increase in the amount of vitamins B2, C, PP, B6 and resveratrol. Rational technological parameters for the extraction of biologically active substances from grapes and their structural components have been established. It has been established that mixing fermented pomace with a 30 % wine-alcohol (juice-alcohol or aqueous-alcohol solution) extractant in a 1:3 hydromodule gives the best result. It is of practical importance to enrich low-extracted juices and wines with extracts obtained from the solid parts of the cluster to produce functional drinks

Experience of using evaporative cooling of graphitized electrodes to reduce their consumption in ore smelting furnaces

Consumable graphitized electrodes (GE) are widely used for supplying current to AC and DC EAF's, ore-smelting and indirectly heated electric arc furnaces. Due to large current, thermal and mechanical loads, their consumption in the structure of the cost of smelting in some cases, for example, in steel smelting reaches 30 %. Considering this, as well as the unstable global economic situation, when many enterprises use imported electrodes, solving the issue of reducing them is urgent. Foreign-made arc steel furnaces with a capacity of 100 tons and more successfully use evaporative cooling (EC) technology. Its use leads to a reduction in graphite consumption by an average of 10–15 %. However, for ore-thermal furnaces, no data on the experience of using EC GE has been found in the literature. The purpose of the work is to study the possibility of reducing the temperature and consumption of GE in arc ore-smelting furnaces when using EC technology. Experimental studies were carried out at the enterprise PC “AVISMA” (Berezniki), which includes three ore-smelting furnaces with a capacity of 100 tons. For the graphite electrodes used in these furnaces, modeling of their thermal state was performed with and without EC. Rational technological parameters of the cooling process were determined: water flow 1.5 m3/h and system turn-on time 5–15 minutes from the start of the current supply. An experimental design of the EC ring and a system for monitoring water and air flow have been developed. As a result of several heats, a decrease in the surface temperature of the GE was recorded when using EC with water on its side surface and a number of shortcomings were identified. Recommendations for improving technology and improving the design of the AI system are formulated

Technological Parameters of Microfiltration in the Production of Micellar Casein Concentrate

Background:: There are many different factors that influence the process of microfiltration, including membrane pore size, pressure, temperature, and membrane origin. Studying the joint influence of technological parameters in order to justify rational modes of microfiltration is relevant. Objective:: This research aimed to define the rational technological parameters of microfiltration, which allow to achieve the target parameters of retentate in the process of obtaining micellar casein concentrate. Methods:: Standard and modified methods and techniques have been used in the process of experimental research. The mathematical processing was carried out by methods of mathematical statistics according to several trials data at three stage sequence. Results:: As a result of experimental investigations, the applicability of ceramic membranes for microfiltration of skim milk has been shown. The rational pore size has been established as 0,1 μm. To obtain the micellar casein concentrate, it is advisably to carry out the microfiltration of skim milk to the mass fraction of dry solids in concentrate (13 ± 3) %, followed by two-phase diafiltration with a double volume of reverse osmosis water. The rational operating conditions, allowing to get the target value of protein fractions correlation, have been established, as described as follows: input pressure as 0,2 – 0,3 MPa, and temperature as 10 – 15°С. Conclusion:: The analysis of microfiltration concentrates and permeates composition of raw milk, including vitamins and minerals content, showed both their high nutritional and biological value and the viability of further processing into food ingredients, including the ingredients for the specialized food products.

Building a model of the abrasion grinding mechanism in a tumbling mill based on data visualization

The object of this study is the grinding process in a tumbling mill when the mechanism of destruction by abrasion is implemented, which is caused by the mechanism of shear loading. The abrasive effect due to the impulse interaction during the mutual chaotic movement of granular particles in the shear layer of loading, characterized by the granular temperature, is taken into account. The task solved was determining the parameters of the shear interaction, which is caused by the difficulties of modeling and complexity of the hardware analysis of behavior of the internal loading in the mill. A mathematical model was built based on data visualization for the abrasion grinding mechanism. The power of the shear interaction forces was taken as an analog of the grinding performance. The initial shear characteristic was considered to be the average value of the shear velocity gradient in the central averaged normal section of the shear layer. The impact on productivity of the granular temperature and mass fraction of the shear layer and loading turnover was taken into account. The effect of rotation speed on performance was evaluated by experimental modeling at a chamber filling degree of 0.45 and a relative particle size of 0.0104. The maximum value of the energy and productivity of grinding by abrasion was established at the relative speed of rotation ψω=0.55–0.6. The results have made it possible to establish a rational speed when grinding by abrasion, ψω=0.5–0.6. This value is smaller in comparison with grinding by crushing ψω=0.55–0.65 and breaking ψω=0.75–0.9. The established effect is explained by the detected activation of the chaotic quasi-thermodynamic movement of particles of the shear layer at slow rotation. The model built makes it possible to predict rational technological parameters of the energy-saving process of fine grinding in a tumbling mill by abrasion

ВИНИКНЕННЯ І РОЗВИТОК ТРІЩИНОУТВОРЕННЯ В ГІРСЬКИХ ПОРОДАХ ПРИ СТАТИЧНОМУ НАВАНТАЖЕННІ

The paper examines the occurrence and development of cracks in rocks under static loads, various conditions and factors of crack initiation and development. For comparison, such rocks as concrete, granite, sandstone, plasterboard are taken. This is said to help the cracks in the rock spread in the right direction. The technology of crack formation with the help of insert plates under the action of non-explosive mixtures is considered. When modeling, the minor and major axes of the ellipse around the insert of the plate with holes are taken. Construct isolines of rock destruction at a point in the form of ellipses. Determine the most likely direction of cracks during rock destruction. The conditions for the development of cleavage cracks relative to the axes of anisotropy with maximum and minimum strength are considered. The theoretical and experimental justifications of the rational technological parameters of mining stone blocks by the hole method by the formation of a separation crack in the rock in a given direction have been studied. The determination of the plane stress state around a hole with a 5- and 8-mm-thick insert plate is studied, and equivalent stress diagrams are given. The methods of directional destruction and the occurrence of cracks in rocks when pouring non-explosive mixtures into wells and inserting cartridges with a destructive substance into wells are considered. It clearly shows the greater efficiency of using cartridges that guarantee the appearance of cracks in a precisely specified direction. The influence of the load scheme on the development of a splitting crack in holes with stress concentrators is presented. The model for the analysis of crack formation at the tops of stress concentrators is considered. Non-explosive methods of directional destruction of monoliths using special structures are described. Considered patents for static rock splitting. The results of destruction over a certain time are given. In addition, non-explosive mining of gabbroid rock blocks using destructive mixtures together with surface-active substances is considered.

Physico-mathematical model of the process of compression of compound feed components into expanders

The purpose of the experimental study is to verify the accuracy of conclusions drawn from theoretical research by substantiating experimentally the main parameters and operating modes of the feed compaction process. To compare the results of numerical modeling and laboratory experiments, a program was developed in the Wolfram programming language, which allows linking the technological parameters of the expansion process (W, T) with the physical and mechanical properties of the compound feeds mixture (Ep, μp, Wp). For rational technological parameters (Dμ = 0.5 mm, W = 20.7 %, T = 137.0 °C), we have the following physical and mechanical properties: Ep = 22.3 MPa, μp = 0.31, Wp = 0.49 N/m. In this case, SΔP = 0.772 MPa, Ψ = 1.519, ha = 13.2 mm. Comparisons of dependencies SΔPE(Dμ) and SΔPT(Dμ), ΨE(Dμ) and ΨT(Dμ), haE(Dμ) and haT(Dμ) will be conducted under the condition of rational technological parameters, and a sufficiently high Pearson correlation coefficient (0.94–0.99) has been established.

РАЗРАБОТКА ТЕХНОЛОГИИ ПРИГОТОВЛЕНИЯ КОРМОВОЙ СМЕСИ С ИСПОЛЬЗОВАНИЕМ ВТОРИЧНЫХ СЫРЬЕВЫХ РЕСУРСОВ

In order to supplying animals with natural vitamins round all year providing and the volume of lowvalue coarse feed without additional energy intensive treatments increasing, feed mixture preparing by the hydroponic method’s technology has been developed. The crushed straw and green fodder grown from cereals or legumes’ components for this mixture are used. The green fodder’s traditional hydroponic cultivation without substrates has root system mass’s large losses, but also does not ensure the plants’ full development. The substrate using in this case by difficulty of root system cleaning is limited. In proposed technology, straw acts not only as a feed mixture’s component, but also as a root habitable base. The rational technological parameters of the affecting green feed highest yield’s production have been determined experimentally. It grain soaking, cultivation, temperature and surrounding air’s humidity, the starting material’s sowing rate and illumination’s duration is included. The straw layer’s waterphysical properties as a root habitable base, its porosity, density and capillary moisture capacity have been studied. An experimental comparison of green feed yield obtained by the proposed technology and the traditional method using has been carried out. The analysis showed that green feed yield increasing is primarily due to root mass’s yield increasing and root habitable base’s water air nutrition has improved. According to the proposed technological scheme, the design of feed mixture preparation’s installation has been developed. This installation’s main structural elements operability has been confirmed experimentally, and the parameters of individual working bodies have been substantiated. Recommendations on the proposed technology using and installation’s design for feed mixture preparation are given. The analysis of the experimental results was carried out, and the corresponding conclusions were done: design solutions using for technological process’s organization at feed mixtures production can significantly reduce final feed products’ cost, and consequently, livestock production’s cost as a whole. The directions of further work on this issue have been determined.

Technological aspects of the production of rocket fairings using radio­transparent ceramics of celsian­willemite composition

The article presents the results of the development of recipes and technological parameters for producing rocket nose cones for high­speed, highly maneuverable aircraft. Considering that most of the radiotransparent ceramic materials existing today are monophase, the authors substantiate the need to use polyphase ceramics, including compounds with low thermal expansion, provided that their dielectric properties meet the requirements for radiotransparent materials (e = 1 ÷ 10, tgd ≤ 10–2). The developed compositions of celsian­willemite ceramics ensure the synthesis of target phases (Zn2SiO4 and BaAl2Si4O8) and the maximum degree of sintering at a temperature of 1200 °C which is 150 °C lower than known analogs. The use of Li2O additive in an amount of 2 wt. % (over 100 %) allows for the formation intensification of target phases and eliminates residual intermediate phases. A technology has been developed for the manufacture of thin­walled products of complex shapes using the slip­casting method. To regulate the properties of non­plastic slips, an additive is recommended that has a complex effect, manifested in increasing the fluidity of the slip, improving its filtration properties, and increasing the castings’ strength. The additive is introduced at the slip preparation stage and contains the diluting component (0.38 % Dolapix PC67) and the adhesive component (0.7 % PVA 1788) at a dosage over 100 % on a dry matter basis. A rational technological scheme and parameters for the manufacture of rocket nose cones from celsian­willemite ceramics have been developed. Products made from celsian­willemite ceramics are characterized by excellent dielectric (e = 2/41 ÷ 2.85; tgd = (0.2 ÷ 2.4)10–2) at a frequency of 1 MHz), physical and mechanical (scomp = 831 MPa, sbend = 207 MPa) and thermophysical (Dt = (225 ÷ 250) °С) properties, which ensure their operational reliability and efficient long­term operation.

Building a model of the compression grinding mechanism in a tumbling mill based on data visualization

The object of the study reported here is the grinding process in a tumbling mill where the mechanism of destruction by crushing is implemented, which is caused by the mechanism of compression loading. The compressive interaction in the active zone of the lower end of the granular loading chamber of the rotating drum at the transition of the shear layer to the solid zone was taken into account. The task to determine the parameters of the compressive action was solved, which was caused by the difficulties of modeling and the complexity of the hardware analysis of the behavior of the internal loading of the mill. A mathematical model was built based on data visualization for the compression grinding mechanism. The power of compressive forces was taken as an analog of grinding performance. The initial characteristic of compression was considered to be the mean speed of movement in the central averaged normal cross-section of the shear layer. The influence on the performance of the mass fraction of the shear layer and the reversibility of loading was taken into account. The effect of rotation speed on productivity was evaluated by experimental modeling at a chamber filling degree of 0.45 and a relative size of grinding bodies of 0.0104. The maximum value of energy and grinding productivity was established at a relative speed of rotation ψω=0.6–0.65. The maximum value of the share of the shear layer loading was found at ψω=0.4–0.45. The results have made it possible to establish a rational speed during crushing by compression, ψω=0.55–0.65. This value was smaller in comparison with impact crushing, ψω=0.75–0.9. The observed effect is explained by the detected activation for the shear loading layer during slow rotation, in contrast to the fast rotation for the drop zone. The model built makes it possible to predict rational technological parameters of the process of medium and fine grinding in a tumbling mill by compression.

Integrated research into the stress-strain state anomalies, formed and developed in the mass under conditions of high advance velocities of stope faces

This paper studies the ways of solving the resource-saving direction of the strategy for the mining industry development in Ukraine. The existing ideas about the patterns of changing stress-strain state (SSS) in the mass during the stope mining of minerals are analyzed. The problem of the host rock SSS formation and development is studied. The main directions of studying the relationship between the parameters of mass SSS anomalies in the area of stope operations and their technological parameters has been substantiated with the selection of a methodology for conducting multivariate computational experiments. A macromodel has been constructed to calculate the change in the distribution fields of the rock mass SSS components with subsequent substantiation of its idealizations. The principles of matching the macromodel and the subordinate models have been studied. A new methodical approach is proposed for taking into account the time technological parameters (average daily face advance velocity and the duration of its stoppage) through their relationship with the mechanical characteristics of the rocks. A test assessment of the adequacy of the performed calculations based on the spatial model SSS analysis for all stress components has been conducted. The degree of influence of the stope face advance velocity and the mass texture on the parameters of rock pressure anomalies has been studied, as well as the linking patterns in the area of conducting stope operations have been obtained: frontal and lateral bearing pressure zones and a zone of destressing behind the stope face. A base has been created for studying and predicting the rock pressure manifestations in critical areas in order to develop recommendations for choosing rational technological and design parameters for high-rate mining of coal seams.

Research on clay raw materials for manufacturing of clinker bricks

We developed a basic approach for determining the possibility of using clay raw materials for the manufacturing of ceramic clinker bricks. A complex of properties is given that allow establishing rational technological parameters of forming, drying and firing of ceramic products. Composite charges were prepared based on clays of different mineralogical types from the Druzhkiv, Siver and Ozeryan deposits (Ukraine). It was established that on the basis of experimental materials by means of plastic forming and firing at temperatures of 1100–11200C it is possible to obtain ceramic clinker bricks with a water absorption of 4–5% and a mechanical strength of 29.8–30.0 MPa, which meets the requirements for clinker bricks. The obtained characteristics of previously unexplored clay raw materials open the possibility of their wide application in the construction industry.

RESULTS OF LABORATORY STUDIES OF THE EXPANDATE FORMATION PROCESS

The expanded preparation of feeds is carried out using high-temperature (80–140 °C) expanders. These expanders perform the task of preparing food products and feeds under high pressure (1–10 MPa). The expansion process is accompanied by chemical changes such as denaturation of proteins, amino acids, vitamins, starch, and enzymes. Additionally, there is a transformation of the physical and mechanical properties of the feed components, converting them into expandates. The laboratory research aims to establish the regularities of the compression pressure changes with the deformation of feed components and the density of the obtained expandates under various technological parameters. The study explores the impact of the granulometric composition of the feed, its moisture, and temperature on the deformation diagram, representing the relationship between stress and material deformation. For this purpose, testing was conducted using the Heckert FP-100/1 testing machine and additional devices and equipment. As research factors, the feed's moisture W (10 %, 20 %, 30 %), temperature T (80 °C, 110 °C, 140 °C), and the average particle diameter of ground feed components Dμ (0.5 mm, 1.5 mm, 2.5 mm) were selected. The study was conducted using a full-factor experiment, comprising a total of 27 experiments with three repetitions. For each experiment, a relationship of compression pressure changes with deformation (elastic hysteresis) of the feed components ΔP(εz) was obtained. The research criteria include: the area SΔP enclosed inside the elastic hysteresis loop ΔP(εz); the coefficient of mechanical losses (or relative hysteresis) Ψ, calculated as the ratio of the hysteresis loop area SΔP to the area enclosed between the stress-strain curve and the abscissa axis, where deformations SP1 are plotted; the height of the obtained expandate sample ha; and the density of the obtained expandates ρa. As a result of the laboratory research on the expandation process, dependencies of the compression pressure changes with the deformation of feed components ΔP(εz) were established. Additionally, correlations of the area of the elastic hysteresis loop SΔP, the coefficient of mechanical losses Ψ, the height of the obtained expandate sample ha, and the density of the obtained expandates ρa with the feed's moisture W, temperature T, and the average particle diameter of ground components Dμ were determined. By solving the compromise task of minimizing the coefficient of mechanical losses Ψ and maximizing the density of the obtained expandates ρa, the following rational technological parameters were obtained, ensuring the most effective feed expansion process: Dμ = 0.5 mm, T = 119.2 °C, W = 19.1%, ρa = 292.9 kg/m3.

Pyrocarbon Coating on Granular Al2O3 for HTGR-Type Power Reactor

Fourth-generation nuclear power systems are based on high-temperature gas-cooled reactors, in which the pebble fuel is the primary energy carrier. In this regard, applying protective pyrocarbon coatings on granulated fuel is an essential problem in ensuring the reliability of nuclear power plants. The article’s main idea is to research rational technological parameters of forming a pyrocarbon protective coating on the granules of a nuclear fuel model. For this purpose, granulated Al2O3 with the protective pyrocarbone coating was applied as a fuel model. The article’s aim is to study the effect of thermophysical parameters on applying a protective pyrocarbon coating on granulated Al2O3. During the experimental studies, thermal imaging of the pyrolysis process was used. The scientific novelty of the work is the equilibrium curves for the systems Al2O3:CH4, Al2O3:CH4:N2, and Al2O3:CH4:Ar. Their analysis allowed for evaluating rational thermochemical parameters of the pyrolysis process. As a result, rational thermophysical parameters of coating granulated Al2O3 with a pyrocarbon layer were evaluated, and the practical possibility of applying the pyrocarbon coating to granulated Al2O3 in the electrothermal fluidized bed was experimentally proven. It was shown that nitrogen does not significantly affect the target reaction product under a temperature of less than 1500 K. Also, the rational conditions for the pyrocarbon coating at a pressure of 0.1 MPa were realized at a temperature of 900–1500 K and using argon. Moreover, pyrocarbon was precipitated from hydrocarbon at 1073–1273 K. Overall, the need to add an inert gas for reducing the carbon black formation was proven to prevent a reduction of natural gas efficiency.

ENERGY- AND RESOURCE-SAVING PROCESSES INVOLVING THE POLYMER PHASE

The paper deals with the processes of application and production of various polymer materials. By coating the surface of mineral fertilizer granules with hydrophobic polymer films, fertilizers with controlled release of nutrient components were obtained. Such fertilizers can prevent the leaching of nutrients, prevent the negative impact on the environment and reduce fertilizer consumption. Methods for calculating the particle distribution function by the degree of coating characterizing the uniformity of coating on fluidized bed particles for stationary and non-stationary modes of operation of the apparatus are considered. The process of applying a thick composite coating to the surface of urea granules in a pan granulator was also investigated. A simple method for calculating the size distribution of the obtained granules with a composite shell is proposed. The actual problem of developing a method for predicting the kinetics of nutrient release from polymer-coated fertilizer granules based on a fairly simple mathematical model of the process has been solved. Studies of the combined polymerization and drying process in the synthesis of polyacrylamide and sodium methacrylate copolymer with methacrylic acid amide have shown that its use at the final stage of obtaining water-soluble acrylic polymers is very effective. This technique allows to reduce the total time of the technological cycle. The process of obtaining polyethylene powder by the method of elastic-deformation grinding of polymer gel and a two-stage process of solvent removal from polymer powder with the return of the solvent to the technological cycle has been developed. The rational technological parameters of the electrodialysis process of contaminated steam condensate of mineral fertilizers plant have been identified, which allows to obtain a more concentrated salt solution, which is used as a secondary raw material, as well as a desalinated solution used as process water. For citation: Lipin A.G., Lipin A.A. Energy- and resource-saving processes involving the polymer phase. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2023. V. 66. N 7. P. 203-213. DOI: 10.6060/ivkkt.20236607. 6836j.

Аналитическая модель равноканального углового прессования титановой губки

Introduction. The use of equal-channel angular pressing (ECAP) of metal powder makes it possible to obtain practically non-porous blanks with high hardness, with a high level of accumulated deformation and with the formation of an ultra-fine-grained structure. A relevant issue for the study of the semi-continuous ECAP process remains a reliable assessment of the energy-power parameters of the process and the prediction of the porosity of compressed materials. This, in turn, is due to the need to develop sufficiently accurate, reliable and simple mathematical models for practical application. The purpose of the work is to develop an analytical model of the process of equal-channel angular pressing of porous material. Powdered screening of spongy titanium of the TG-100 brand was selected as a model of the material for the study. The object of the study is the process of semi-continuous equal-channel angular pressing of axisymmetric porous briquette of titanium sponge in the channel of the mold. It is assumed that the ECAP uses a punch to create back pressure. For the solution, a process scheme, a statically permissible load scheme on a layer of intense deformation and a kinematically permissible flow scheme of a plastically compressible medium in a layer are determined. A system of equations is constructed in accordance with the accepted schemes. The equation power balance is applied. The analytical equation is solved by the method of successive approximations. Finite element simulation of the porous titanium ECAP process was carried out at the angles of intersection of the mold channels at 45°, 50°, 55° and 60°. Results and Discussion. The porosity of the blank is determined at different stages of the ECAP process. A diagram of the change in pressure on the punch using the analytical solution and finite element simulation is obtained. It is revealed that the results of the analytical solution are consistent with the data of the finite element simulation. The highest stress level occurs in the process of equal-channel angular pressing at α = 45°, however, the distribution of relative density over the cross section is most uniform. The maximum value of the pressure on the working punch decreases with an increase in the angle α. Rational technological parameters of pressing porous blanks should provide the maximum permissible pressure on the deforming tool. From this condition, in each specific ECAP process, it is possible to determine the optimal angle value from the analytical solution.

Production of steel overall shells by hot crimping

The crimping process of a thick-walled overall pipe made of 07Kh16N6 steel is considered. A study of the power modes and the limiting possibilities of the crimping operation is carried out. Rational technological parameters are established. Experimental equipment is designed.

EXPERIMENTAL RESEARCH AND DEVELOPMENT OF A METHOD FOR CALCULATING THE PARAMETERS OF BOREHOLE HYDROMONITOR DISINTEGRATION OF RICH IRON ORE IN PLACE

Purpose. Study and development of a rational methodology for calculating the parameters of the process of downhole hydrodisintegration of martite ore massifs by pressure rotating water jets. Methods. Mine experimental-methodical and experimental-experimental works on: stage-by-stage study of the engineering and geological situation of ore deposits and selection of experimental sites; development of technological schemes for the hydrodisintegration of the ore in place and the creation of appropriate experimental equipment; selection of means for providing hydro-extracting operations; the choice of methods for monitoring and measuring the parameters of the hydrodisintegration process; generalization and analysis of the results of experiments and development of recommendations for the creation of technology and equipment, taking into account the achieved indicators. Results. A technique for calculating the parameters of hydrodisintegration of rich martite ores martite ore in places has been developed based on the study of the features of the formation of rotating compact water jets by borehole hydromonitors. Scientific novelty. Relationships between the structural and morphological characteristics and jointing of martite ores (porosity, the ratio of the grain composition of the ore, the ultimate uniaxial compression strength of ore and lumpiness) and the parameters of the hydromonitoring effect (water pressure, the initial diameter of the jet and the speed of its movement along the exposure of the face), which make it possible to determine rational technological parameters of hydrodisintegration products. Practical implication. Borehole hydromonitor disintegration of martite ores in place is a combined ore preparation process, including enrichment grinding operations and classification of destruction products according to their granulometric composition during their erosion. At the same time, there is a selective opening of ore-forming minerals that improve the quality of the ore by 0.5–1.5% compared to natural, a decrease in the mass fraction of silica from 2.0–1.2 to 0.5–0.3%, which ensures the production of iron ore raw materials of the highest quality – superconcentrates with an iron content of 69.0–69.5%. Control of the granulometric composition of hydrodisintegration products is achieved by adjusting the initial water pressure at the outlet of the jet nozzle, the speed of the jet along the face exposure and the orientation of the jet relative to the elements of occurrence and texture of the ores.

Determination of approaches to the development of ceramic compositions for the manufacture of facial bricks

This paper considers the principles of designing a composite mixture for the production of ceramic facing bricks based on clay materials. The complex of conducted researches allows establishing rational technological parameters of molding and firing of ceramic products to achieve high values of operational properties. Composite charges were obtained based on clays from Druzhkovsky and Zalyutinsky deposits, as well as on clay wastes of zircon-ilmenite sand enrichment from Vilnohirsk Mining and Metallurgical Plant. It was established that based on these materials by forming via the method of rigid extrusion and application of firing at temperatures of 1020–10400С, it is possible to fabricate a ceramic brick of grade not lower than M225.