In this study, we aim to identify shortcomings in the operation of multisatellite planetary gearboxes and to justify improved designs of planetary self-aligning mechanisms, which allow torque to be transmitted through all installed satellites. To that end, we studied a domestic planetary three-satellite MPZ gearbox installed on a magnetic separator, designed for wet separation of strongly magnetic ores and materials into magnetic and non-magnetic products, and a planetary gearbox of a special structure. 3D models of the classical three-satellite and single-sliding self-aligning gearboxes were constructed in the 3D module of the T-Flex CAD software. The performance of the mechanisms was evaluated by structural analysis and Chebyshev’s mobility formula. The constructed 3D models were used to study the engagement process of the classical three-satellite and single-sliding self-aligning gearbox. The latter is distinguished by the presence of two levers, which are introduced additionally to three satellites. During the research, the lateral clearance between the pairs of satellite teeth and center wheels was accepted according to GOST 1643–81. The conducted analysis of contacts at rotation of the central driving wheel by 30°, 110°, 200°, and 310° established further designing of the applied planetary gears to be inexpedient due to impossibility of realization of power transfer simultaneously through all satellites. The main disadvantage of the operation of multisatellite gearboxes was found to be the requirement for the side clearance selection, which should ensure the operability of the transmission at the moment of motion transfer. When designing multi-satellite single-slide selfaligning planetary mechanisms, additional levers should be introduced into the structure, the number of which should be equal to the number of satellites. Hence, the use of self-aligning planetary gears makes it possible to reduce the dimensions due to the uniform distribution of the transmitted torque, since the calculated value of the torque can be reduced by the number of satellites. This allows the gears to be adapted to the working loading conditions, which significantly improves the performance of the entire machine or unit.

This work addresses the problem of improving the surface quality of parts of rotation bodies, which are made of hardened steels, in the course of their machining on lathes with numerical program control. The research object was the surface roughness of parts. The methodology involved system analysis and synthesis, artificial neural networks, fuzzy logic, experiment, and processing of experimental results. A decomposition scheme for the expert system structure was developed, which can be used as the basis for formulating requirements to a future expert system for monitoring and prediction of roughness parameters. It was established that the models currently applied to describe the relationship between surface quality and the technological regimes used to ensure the technological level of roughness give a high error of over 20%. The possibility of using models that apply artificial intelligence and contain neural network blocks and decision-making devices based on fuzzy logic is substantiated. It is shown that such a combination makes it possible to customize the system for processing parts of a certain production range, as well as a more correct assessment of the onset of catastrophic wear of cutting tools. The neuro-fuzzy model was confirmed to have an error of less than 10%, which is significantly lower than when using spectral or correlation models. According to the testing results, the proposed expert system for monitoring and prediction of roughness parameters enables a 2.5-fold reduction in the scatter of roughness parameters under an increase in tool wear, compared to without its application. Thus, the proposed system makes it possible to assess the level of cutting tool wear more correctly and determine the onset of its limit state.

We set out to improve the existing design of a polycrystalline diamond bit with a steel or matrix body with the purpose of creating a hydro-monitoring effect. The research object was the hydraulic system of a diamond bit with a near-bit jet pump. The near-bit ejector system was studied by a theoretical analysis of the operation of the bit hydraulic system by means of canonical dependencies and hypotheses. A hydraulic system for a polycrystalline diamond bit is proposed. This system includes a high-pressure jet pump, which enhances the hydro-monitoring effect at the bottomhole. The main hydraulic characteristics of the bit flushing system with a jet pump are as follows: at a drilling pump feed of 18.4 l/s and a drilling fluid density of 1180 kg/m3, the working coefficient of jet pump injection equals 0.34; the working nozzle diameter equals 10.3 mm; the mixing chamber is 11.9 mm, bit hydromonitor nozzles are 11.1 mm; the number of hydromonitor nozzles is 3; the velocity at the exit of hydromonitor nozzles is 85.0 m/s; the pressure drop at the bit is 15.7 MPa. The possibility of using the hydro-monitoring effect enhanced by a near-bit jet pump was substantiated, since the velocity at the exit from the hydro-monitoring nozzles is sufficient to destroy most rocks (sandstone, limestone, dolomites, rock salt, gypsum stone, basalt, marble, granite). The jet pump in the proposed design of a polycrystalline diamond bit creates an additional circulation circuit above the bottomhole, injects cuttings from the annular space and feeds them to the hydro-monitor nozzles. This enables a more efficient destruction of the bottomhole rock. The power of hydro-monitor jets is sufficient to improve drilling performance.

The objective of the present exploration is to examine impactions of radiation, a non-uniform intensity source, and a permeable medium on a temperamental MHD blended convective micropolar liquid over an extended sheet subject to Joule heating. To transform the formulated problem into ordinary differential equations, the applicable similarity transformation is implemented. By utilizing R-K-F 4th -5th order approach with shooting method with MATLAB, the numerical solution is obtained. For the relevant profiles, the dimensionless parameters are visually displayed and described. Skin friction, the Nusselt number, and the Sherwood number have all been calculated using the answer found for the velocity, temperature, and concentration. With the assistance of line graphs, the impact of different flow factors being introduced into the problem is addressed. This research is conducted on the implications of MHD, porous, thermal radiation, viscous dissipation, Joule heating, non-liner thermal radiation and chemical reaction. For large values of micropolar parameter, the temperature is reduced and velocity and angular momentum distributions are raised. With the thermal radiation parameter, the temperature distribution gets better and thermal boundary layer is improved while the large values of Eckert number and non-uniform heat source or sink parameters, thermal boundary layer is improved. The higher thermal conductivity is proportional to the thickness of the thermal boundary layer. The concentration profile degrades with higher Schmidt number and chemical reaction parameter values. The current examination pertains to the significant subject matter of cooling of systems, artificial heart identification, oil-pipelined frictions, flow-tracers.

In this work, we develop a neural network model based on experimental heating and cooling curves of insulated wires of overhead lines under changes in wind speed and its direction relative to the wire axis. Insulated SIP-3 wire used in overhead lines was investigated. A multilayer perceptron neural network was employed to model the process of heating and cooling of insulated wire under changes in wind speed and its direction. The average absolute error was taken as a criterion for evaluating the prediction accuracy of wire core and insulation temperatures. The main parameters of the developed neural network model include the number of hidden layers and neurons in each hidden layer, the degree of regulation, and the regulatory rigidity of the model. The modelled heating and cooling curves of insulated wire were compared with those obtained experimentally. The average absolute error was equal to 1.74 and –4.08°C for the predicted core and insulation temperatures, respectively. The difference between the heating curves at low wind speeds was found to range within 9°C. It was shown that an increase in wind speed leads to a decrease in the difference between the curves. Our analysis showed that neural network models used for predicting variations in the temperature of insulated overhead lines should be trained using a larger number of input parameters. This is the main prerequisite for high prediction accuracy of such models, when the difference between the simulated and experimental data does not exceed 5%.

The aim was to develop a methodology for selecting an optimal wire grade and cross-section for overhead power lines with a voltage of above 1 kV under intensive development of power grid systems. This aim was solved using the authors’ previously developed methods: selection of an optimal wire grade based on hierarchy analysis and selection of an optimal wire cross-section by optimizing the specific discounted costs during the entire period of construction and operation of overhead power lines. In the present study, these methods are integrated into a single methodology. It is proposed to implement wire inspections prior to the stage of technical and economic calculations, since the necessary data has already been taken into account during the selection of a wire grade and its cross-section. The proposed methodology was tested on a typical example of reconstruction of the Zapadnaya– Davydovka 110 kV overhead line, which creates limitations in the power supply of Primorsky Krai due to insufficient wire capacity and its operation beyond the normative period. SENILEK AT3/C 150/24 wire was selected as a solution for the example under consideration. The application of this wire grade allows not only the overhead line capacity to be increased by 151% without replacing the existing supports, but also active and reactive power losses in the electric network to be reduced by 18.9 and 2.5%, respectively. The proposed methodology enables selection of an optimal grade and cross-section of any wire design, taking the dynamically changing operational conditions of power grid systems into account. The solutions found by the proposed methodology may contribute to a more efficient operation of power lines due to increasing their transmission capacity, reducing the number of used supports, replacing the line wire without replacing supports, decreasing ice formation on wires, and reducing power losses.

This work evaluates the influence of a new controlled voltage regulator on the current and voltage non-sinusoidality in different sections of a power supply system during smooth (discrete) voltage regulation on the high-voltage side of a shop transformer. The MatLab software application was used to develop a block-modular model for a transformer substation with the proposed controlled voltage regulator and measurement modules. The developed model was used to investigate the current and voltage non-sinusoidality in different parts of a power supply system when stabilizing the voltage at the consumer end at a given level. The study was carried out using a shop transformer with a capacity of 1 MV∙A and a voltage of 6/0.4 kV under an active-inductive character of the load with the load current phase angle of φ=45 deg. The obtained results confirm that, due to the extended functional capabilities of the proposed technical solution, the voltage at consumers is maintained at a given level under high technical and economic performance. When the network voltage is reduced by 5% and the activeinductive load current is increased by 35%, the proposed device was shown to create voltage non-sinusoidality. The voltage non-sinusoidality value does not exceed the permissible domestic and international norms. In addition, the proposed device is capable of maintaining the voltage at the consumer end at a given level. The obtained integral characteristic of voltage stabilization shows that the application of the proposed technical solution instead of the existing mechanical voltage regulator of the “switching without excitation” type allows the nominal voltage at the busbar of the switchgear to be retained. Further research will investigate voltage stabilization at consumers with simultaneous compensation of reactive power for complex improvement of technical and economic indicators of power supply systems under the conditions of unstable supply voltage and load current.

In this work, we set out to investigate the influence of operating currents of SF6 circuit breakers on the magnitude of overvoltages during switching of converter transformers. The experience of electrical equipment operation is analyzed with a focus on the problems associated with the natural aging of insulation, overloads, and switching overvoltages. The methods of equipment diagnostics were used. According to statistical data, at present, about 37% of short circuits between phases and 42% of single-phase earth faults in electrical networks of industrial enterprises occur due to switching overvoltages. The conducted tests showed that the overvoltages emerging during switching by SF6 circuit breakers of converter transformers, which are used in aluminum smelters, may reach a three-fold rated voltage of the network. This threatens the insulation of transformer windings, cable line, and the switch itself. It was established that an increase in operating currents of an LF2 circuit breaker, not exceeding 27.8% of the rated current of the switch, leads to an increase in overvoltages during switching of converter transformers. At a further increase in the operating currents of the circuit breaker by more than 27.8% of the rated current of the circuit breaker, a sharp decrease in the value of switching overvoltages is observed. Therefore, the operating currents of SF6 circuit breakers were established to affect the level of switching overvoltages of converter transformers. The underlying mechanism of this phenomenon was determined, which should be taken into account when improving the reliability of power supply of converter transformers and, consequently, the reliability of aluminum production. The feasibly of resistive-capacitive dampers as the most effective means for limiting overvoltages during switching of converter transformers was confirmed.

This paper presents a brief review of the designs, characteristics, and operating parameters of Stirred media mills supplied by foreign manufacturers. An analysis of information on Stirred media mills , which are used to improve the efficiency of beneficiation and metallurgical operations, is carried out using available publications. The obtained results indicate the inexpediency of using conventional drum ball mills for flotation separation of ores and concentrates with a fine interpenetration of minerals. The application of conventional mills in extraction of ores and concentrates resistant to cyanidation, where gold is finely disseminated in sulfides, is limited by their high power consumption and the corresponding operating costs. In this work, different types of Stirred media mills are considered, including their vertical and horizontal types. The advantages of Stirred media mills over conventional ball mills, particularly in terms of energy efficiency, are noted. The designs and main characteristics of Stirred media mills , which have received wide application, are presented. According to the data presented in the reviewed publications, the main parameters determining the grinding process in such mills are outlined, including the ratio of bead size to mill feed size, density of grinding medium, density of pulp in the mill, volume loading of beads, stirring speed, etc. The conducted analysis of literature data indicated high efficiency of mills based on agitation of grinding media for fine and ultrafine grinding of ores and concentrates in comparison with conventional ball mills. Given that the volume of ores and concentrates resistant to processing by conventional methods is increasing, the application of Stirred media mills is expected become more widespread, thereby increasing the efficiency of subsequent beneficiation and metallurgical operations.

This paper presents literature review of the existing problems and solutions in protecting carbongraphite electrodes from the destructive environment of arc steel-making furnaces, magnesium and aluminum cells. The most significant publications on the corrosion resistance of cathodes and anodes in relation to physical, chemical, and electrochemical wear, to oxidizing environments, to active components of the introduction and destruction of the carbon structure are discussed. An analysis of various proposals and engineering solutions for reducing or eliminating the impact of aggressive environments on electrodes under specific operating conditions of metallurgical units is carried out. It was established that losses from lateral oxidation of the electrode surface of arc steel-making furnaces, when passing the temperature zone of 600–800°C, may reach 40–60% of the total consumption. Carbon-graphite products are subject to a significant destructive effect of the specific interaction of carbon with elements and compounds of the working environment, which can be introduced (intercalate) into the interlayer structure of carbon. The existing engineering and technological solutions mainly apply to the protection of the product surface; moreover, they perform their functions for a short time, rather than during the entire service life of the metallurgical unit. In this connection, it is proposed to focus on ensuring volumetric protection of electrodes from the effects of an aggressive environment. Intermediate results obtained in the field of synthesis of carbonbased composite materials adapted to the conditions of electrode production at existing enterprises are presented, along with the results of studies into the oxidizability of these composites. The existing and proposed engineering solutions for protecting the surface of carbon products have not received wide recognition or are not used in the metallurgical industry. Among the most probable reasons are the limited period of electrode surface protection, the complexity of reproduction, or the lack of profitability due to the high cost of protective components. In this regard, synthesis of C – TiC/TiB2 composite electrodes based on petroleum coke and graphite seems to be a promising research direction.

In this paper, we investigate the behavior of associated elements (tungsten, molybdenum, and bismuth) contained in a sulfide gold-bearing concentrate during its autoclave oxidation. The process is studied using a sulfide flotation concentrate, crushed to a particle sieve mesh size of minus 0.045 mm and containing 22.1 g/t of gold, 133.2 g/t of silver, 2.7% of tungsten, 13% of molybdenum, and 0.7% of bismuth. The process was carried out in a 2 dm³ autoclave at a temperature of 220ºC and an oxygen partial pressure of 0.7 MPa. The concentrations of sulfuric acid and iron ions in the solution were determined by titrimetric analysis. Inductively coupled plasma atomic emission spectroscopy was used to determine the concentrations of bismuth, tungsten, molybdenum, copper, silver, and arsenic in the solution, as well as the content of bismuth, tungsten, molybdenum, copper, arsenic, lead, and iron and sulfur forms in the cake. The cake was also examined using diffraction analysis. Experiments on cyanidation of oxidized cake were carried out in the pH range of 10.0–10.5 and a NaCN concentration of 1 g/dm³ with a PuroliteS992 ion exchange resin for 24 h. Autoclave oxidation experiments showed the sulfide oxidation degree to be higher than 99%. Extraction of molybdenum into solution in the form of [MoO₂(SO₄)n]^-(2n-2) and MoO ²⁺ amounted to 95%. The decrease in the solid mass led to an increase in the concentration of bismuth and tungsten in the cake, with their contents reaching 1.66% and 12.7%, respectively. The main phases in the cake were established to be scheelite, anhydrite, plumboyarosite, and bedantite. The extraction of precious metals at the subsequent cyanidation stage amounted to 97.5% of gold and 91.6% of silver. Therefore, autoclave cyanide processing of sulfide gold-containing concentrates leads to a molybdenum extraction in the autoclave oxidation solution at the level of 95%. During cyanidation, more than 90% of gold and silver are extracted. Due to the significant amount of tungsten (17%), bismuth (0.9%), lead (5.3%), and molybdenum (3.3%), the obtained cake cannot be considered a waste product.

In this work, we aim to establish the main regularities of hydrothermal precipitation of copper from the previously unstudied sulfuric-nitric acid and sulfate solutions of atmospheric and autoclave processing of metallurgical dusts. Pyrite was used as a sulfidizer. The elemental composition of the products was determined by X-ray fluorescence, inductively coupled plasma atomic emission spectrometry, and atomic absorption analysis. It was found that copper precipitation by the proposed technology enables its recovery at a level of more than 95%. For sulfate solutions with a high arsenic concentration, a two-stage scheme of oxidation-hydrothermal treatment with the following parameters was proposed: temperature 180°С, duration 2 h, oxygen consumption 0.026 dm³/g pyrite (for the 1st stage), and 200°С and 2 h (for the 2nd stage). Extraction in the cake amounted to 95.4% of copper (in the form of Cu₂S) and 91.4% of arsenic (in the form of FeAsO₄), which allowed further separation of these metals by flotation. An autoclave treatment of a Cu–Zn–Fe–As–NO₃ solution in the presence of pyrite at 180–220°С produced the activation energy values (kJ/mol) corresponding to the kinetic regime calculated by the two methods: 64.6 by the conventional method and 60.5 by the shrinking core model. The kinetic parameters of CuSO₄–H₂SO₄–FeS₂–H₂O and CuNO₃–H₂SO₄–FeS₂–H₂O systems were also determined. Flotation enrichment of copper autoclave precipitation cake was shown to result in a high degree of Cu and As separation, with the recovery amounting to Cu ˃ 95% and As ˂ 5%. Precious metals contained in pyrite are transferred to a flotation concentrate by 92.7% (Au) and 96.5% (Ag). The composition of the resulting flotation concentrate comprised (%): 12 Cu; 37 Fe; 38 S; 13 other elements. It is shown that, in order to obtain a product with the required content of copper, flotation concentrate should be separated into pyrite and copper concentrates followed by an additional flotation of primary copper concentrate in an alkaline medium in the presence of lime. Hence, our study has established the main regularities of hydrothermal precipitation of copper from the sulfuric-nitric acid and sulfate solutions of atmospheric and autoclave processing of metallurgical dusts.

Correlation dependencies between the dynamic viscosity of slag and its structural parameters were studied to determine an optimal basicity of silicon smelting slag under the addition of boron oxide to eliminate slagging of the bottom of ore-smelting furnaces. Experimental studies were conducted on CaO–SiO₂ and CaO– SiO₂–B2O₃ model slags obtained at 1600°С. Raman spectroscopic analysis was carried out using a Horiba JobinYvon HR800UV analyzer (France). Theoretical calculations of slag viscosity were performed using Urbain and Mills models. During the experiments, the key structural parameters of slag systems varied within the following limits: the experimental Raman spectrum deconvolution function from 1.41 to 2.45 and optical basicity from 0.58 to 0.68. The obtained experimental and theoretical data were related by mathematical dependencies. It was found that the dynamic viscosity of slag can be promptly determined by Raman spectroscopy on the basis of mathematical models. The dependence obtained shows that slag viscosity decreases upon an increase in the number of bridging oxygen atoms in the silicate anion structure. Notably, this decrease in slag viscosity is observed up to the value of the experimental Raman spectrum deconvolution function of ~1.55-1.60 or slag optical basicity of 0.60–0.62. When B₂O₃ is added, the viscosity undergoes a further decrease. In practice, for CaO–SiO₂ slag systems, the use of boroncontaining flux as a liquefying agent is reasonable at CaO/SiO₂ = 0.61–0.63 while maintaining the content of B₂O₃ in the slag at a level of 1%. The two models (classical and modified) proposed by Urbain were established to be more suitable for theoretical calculation of viscosity in CaO–SiO₂ and CaO–SiO₂–B2O₃ systems. Mills’ model is not suitable for these purposes, since the correlation coefficients in the corresponding mathematical model are not sufficiently large. Further research in this direction is required in order to establish appropriate dependencies of slag viscosity on its structural parameters at different temperatures.

The kinetic characteristics of dissolution of copper-bearing sulfides – chalcopyrite (CuFeS₂) and bornite (Cu₅FeS₄) – in nitric acid were studied. The kinetics of the dissolution process was described using a compressible nucleus model. Chalcopyrite of the Vorontsovskoye deposit and bornite of the Karabash deposit were used as research objects. Solution and cake samples were analyzed by optical emission spectrometry and X-ray fluorescence analysis, respectively. The results obtained were processed in the MS Excel software package. The influence of various factors, including temperature, solvent concentration, particle size, and process duration on the dissolution degree of minerals was studied. The process parameters were varied as follows: temperature – from 35 to 95°C; HNO₃ concentration – from 1 to 9 mol/dm³; particle size – from +0.1 to 0.056 mm; duration – from 0 to 60 min. It was established that an increase in temperature and acid concentration leads to a significant increase in the degree of dissolution of both chalcopyrite and bornite. A decrease in particle size also contributes to a more efficient dissolution of both minerals in nitric acid. The calculated activation energy values were 55 kJ/mol for chalcopyrite and 43 kJ/mol for bornite, which is characteristic of the kinetic region of the process. The reaction orders in terms of reactant were determined: 1.62 for chalcopyrite and 1.57 for bornite. In terms of particle size, these were -1.16 for chalcopyrite and -2.53 for bornite. On this basis, generalized equations of dissolution kinetics for both minerals were derived. The results obtained allow an assumption about the kinetic nature of dissolution of chalcopyrite and bornite under the studied conditions.