This paper examines the characteristics of fine grinding processes under different directions and types of mechanical impact. A theoretical analysis was conducted for four representative cases of loading a spherical particle by grinding media: one-sided, two-sided, and combined impacts with mutually perpendicular force directions. To determine the theoretical fineness of grinding, a mathematical model based on the Hertz–Shtaerman contact problem and previously developed dependencies was applied. The calculation results showed that two-sided impact provides a higher degree of grinding compared to one-sided impact at the same collision velocities. This effect is explained by the formation of a more uniform stress–strain state within the particle and by more complete utilization of impact energy. In multivector loading cases, where the directions of forces are mutually perpendicular, the calculations were performed using the resultant velocity, which allowed for an adequate assessment of the combined influence of differently oriented forces. The obtained theoretical relationships can be used in the design of energy-efficient fine grinding methods and the development of new mill designs that implement multivector loading modes. The results contribute to the advancement of the scientific foundations of energy saving in solid material disintegration processes and provide prospects for optimizing industrial grinding technologies.

10.48081/BGQF1907

2026

Issue 1

Finding optimal methods for processing accumulated chromium-containing waste is a pressing issue in the metallurgical industry. Considering the growing demand for ferrochrome, recycling chromium-containing wastes to produce commercial chromium concentrate is considered the most feasible approach. Existing processing methods demonstrate the possibility of using an inexpensive and widely available reagent – sulfuric acid. Chromium-containing waste also includes dust collected by the wet method from the exhaust gases of ore-smelting furnaces during the smelting of carbon ferrochrome. The accumulation of this dust poses a serious environmental problem, as it contains significant amounts of chromium and other components that can negatively impact the environment. This article presents the results of a study of the chemical and phase composition of chromium-containing dust and presents laboratory experiments on its sulfuric acid leaching. The research was conducted in two areas: sulfatizing roasting followed by sinter leaching and direct leaching of dust with sulfuric acid solutions. Experimental data confirmed the high efficiency of sulfuric acid, which ensures the conversion of a significant portion of the chromium into solution and the subsequent recovery of chromium concentrate. The use of an inexpensive reagent reduces the cost of the process and makes it possible to recycle large volumes of waste generated during ferrochrome production. Implementing this approach will not only yield secondary raw materials for metallurgical production but also significantly reduce the environmental impact associated with the storage and accumulation of dust in landfills, thereby improving the environmental safety of enterprises.

10.48081/BGQF1924

2026

Issue 1

For single-track railway sections, the development of an optimal train timetable is a task of particular importance and constitutes a core component of train flow planning. On single-track railway sections, train conflicts, queueing delays, and overtaking of trains operating at different speeds and in opposite directions lead to an increase in overall delay. In this regard, the problem of developing a balanced timetable by regulating train speeds and optimally determining stations for overtaking operations is of significant relevance. The objective of this study is to design a balanced train timetable with a minimum delay coefficient, taking into account the influence of train running speeds. An optimization model is proposed that considers permissible speed constraints to determine the optimal running speeds of each train along the railway line. The proposed model aims to minimize total delay time while accounting for differences in train arrival times at stations, safety requirements, and speed relationships. The proposed model has practical significance in increasing the line capacity and carrying capacity of railway sections, as well as in improving transportation efficiency compared to existing methods and enhancing operational stability under conditions of uneven traffic flows.

10.48081/BGQF1932

2026

Issue 1

The results of modeling and experimental studies focused on improving the technological process for producing low-alloy steels with an enhanced level of performance properties and environmental sustainability are presented. An increased level of consumer properties was achieved by reducing non-metallic inclusions in the steel during secondary metallurgy (out-of-furnace treatment). Environmental sustainability was ensured through the use of a flux-forming additive based on waste refractory materials containing Al2O3. This material enabled the stabilization of refining slags, reduced steel production costs, and served as a substitute for fluorspar CaF2. To investigate the feasibility of using this flux-forming additive in secondary treatment units, slag samples from several metallurgical enterprises were analyzed. Samples were taken during the metal processing stages in the ladle furnace (LF) unit. The refining and physicochemical properties of the selected slag samples were evaluated through calculations using a polymer model of slag structure. The possibility of stabilizing refining slags using an Al2O3-based additive derived from refractory waste has been confirmed. It is shown that the introduction of Al2O3 into the slags—allowing for operations with highly basic slags—improves the surface properties of the slags, increases refractory lining durability, and reduces metal losses in the form of droplets (beads) as well as the quantity of non-metallic inclusions. Using experimental data from literature and thermodynamic calculations, it was determined that the maximum permissible Al2O3 content in the slag, from the perspective of ladle furnace processing technology, is no more than 30%. The results of experiments on stabilizing model slag with the studied additive showed that, in this case, a primarily chemical stabilization method is implemented.

10.48081/BGQF1921

2026

Issue 1

This article presents the mathematical modeling of thermo-frictional milling with pulse cooling of HARDOX 450 steel using ANSYS Workbench software. The model enables dynamic investigation of the thermal and physical processes occurring within the cutting zone. The developed methodology is focused on analyzing heat distribution during the cutting process and determining optimal parameters for thermo-frictional milling with pulse cooling for high-strength, wear-resistant steels, specifically exemplified by HARDOX 450. To perform the study from a variety of existing models of fracture during cutting, a criterion was used that was first proposed by Professor V.L. Kolmogorov and adapted to conditions of large plastic deformations and high temperatures. In order to increase computational efficiency, a simplified mathematical model was proposed, including two objects: a parallelepiped-shaped workpiece made of HARDOX 450 steel and the cutting edge of a friction milling cutter in the form of a plate. The model took into account the friction coefficient between the cutting edge of the friction cutter (plate) and the workpiece, assumed to be μ = 0.4. To analyze the temperature field in the subcontact layer of the workpiece, the coordinates of nine characteristic points were entered at uniform intervals in the local coordinate system. As a result of modeling, the contact temperature values at these points were obtained at different friction cutter rotation frequencies. The results of the study showed the possibility of effective thermal process control during thermo-friction milling with pulse cooling of HARDOX 450 steel.

10.48081/BGQF1911

2026

Issue 1

This paper examines the physicochemical and mineralogical properties of pellets produced from secondary aluminum slags with the addition of silica-enriched aspiration dust from ferroalloy production. To incorporate finely dispersed industrial waste into metallurgical processing, a pelletizing method was applied in a disk granulator using an aqueous lignosulfonate solution as a binder. The resulting pellets were subjected to high-temperature firing at temperatures of 600, 800, and 1000 °C. The phase and mineralogical composition were studied using X-ray diffraction and petrographic analysis, and the microstructure was analyzed using electron microscopy. It was found that increasing the firing temperature intensifies solid-phase interactions and forms calcium silicate and aluminosilicate phases, such as wollastonite, dicalcium silicate, and mullite. The introduction of aspiration dust with a high SiO₂ content helps reduce the sintering onset temperature and strengthen the pellet structure by forming a binding silicate matrix. It has been shown that optimizing the composition and firing temperature allows for the production of heat-resistant and mechanically strong pellets, promising for use in processes for producing ferrosilicon with increased aluminum content.

10.48081/BGQF1923

2026

Issue 1

The paper considers the design of a built-up large-module gear with inserted teeth and covers installed on both sides of the rim. The relevance of the study is обусловлена the need to increase the maintainability and service life of gear transmissions through the use of built-up designs while maintaining their structural strength and reliability. A distinctive feature of the proposed design is the absence of force clamping of the teeth by the covers: the teeth are fixed by seating them in the grooves of the gear body, while the covers perform an auxiliary function of limiting axial displacement. An analytical calculation of the fastening elements of the covers was carried out taking into account the action of the axial component of the meshing force as well as the load distribution among simultaneously operating teeth. The strength of the bolts was verified under shear conditions and allowable stress criteria, which made it possible to substantiate their size and quantity. Special attention was paid to the selection of the cover thickness, which was chosen to be minimal in order to avoid interference with the meshing process and to prevent an increase in the gear mass. To validate the results of the analytical calculations, numerical modeling of the stress–strain state of the covers and fastening elements was performed using the finite element method in the ANSYS software package. As a result of the simulation, fields of principal stresses were obtained, demonstrating a low level of stress in both the covers and the bolts. It was established that the adopted cover thickness and selected fastening parameters provide a significant safety margin and do not lead to the occurrence of dangerous stresses. A comparison of analytical and numerical results confirmed the correctness of the adopted calculation scheme and the feasibility of applying the proposed design solution in the design of built-up gears with inserted large-module teeth.

10.48081/BGQF1916

2026

Issue 1

The article presents the results of the development and testing of a conical rotor centrifuge for the primary purification of vegetable oils, specifically safflower oil, using flax fibers as a filter material. The design of the installation is described, combining centrifugal separation with barrier filtration through a layer of fibrous material. Experimental studies were conducted to determine the optimal operating parameters: oil temperature (35°C), mass fraction of impurities (0,1%), and separation factor (1300). It has been established that the proposed technology allows achieving an oil purification degree of up to 93% and reducing the sludge content to 0,02%. Using experimental design methods, a regression equation was obtained, describing the influence of the main factors on the process efficiency. The developed centrifuge is an economically efficient solution for small and medium-sized processing enterprises, promotes the implementation of resource-saving technologies and the utilization of secondary raw materials. Furthermore, it demonstrates significant potential for adaptation to other types of oils and production conditions.

10.48081/BGQF1915

2026

Issue 1

This article presents a scientific and technical justification for the use of a sand-polymer composite material (SPC) as an alternative to steel for the manufacture of key load-bearing components (shells and barrels) of belt conveyor rollers, particularly those used in the mining industry. To confirm the feasibility of the concept, computer strength modeling of an LKR-1000 roller with SPC elements was conducted, followed by a comparative analysis of the stress-strain state (SSS) with a similar steel structure (S35 steel). For the modeling, the composite shell thickness was assumed to be 10 mm, while the steel shell thickness was 3.5 mm. Calculations were performed with loads varying from 200 to 600 kPa. The results showed that, despite the fact that SPC is a less rigid material and exhibits greater stresses (70 MPa versus 55 MPa for steel at 400 kPa) and displacements (0.64 mm versus 0.097 mm at 400 kPa), its factor of safety (FOS) remains at an acceptable level (FOS ≥ 1.5) for loads up to 600 kPa. At a maximum load of 600 kPa, the FOS for SPC is 1.6. A key advantage is the 37% reduction in the weight of the roller with composite elements compared to its steel counterpart, which contributes to reduced energy consumption and increased conveyor drive efficiency. The study scientifically substantiates the feasibility of using SPC in conveyor rollers, offering a lighter and more efficient solution for the mining industry. Key words: stress, deformation, displacement, shell, roller.

10.48081/BGQF1908

2026

Issue 1

This paper investigates the impact of stochastic permission-transfer delays on the capacity of a railway section. The study focuses on a single-track section equipped with semi-automatic blocking, which is characterized by a high variability of time intervals caused by operator involvement and the interaction of technical systems. An additional parameter accounting for the stochastic component of permission-transfer delays is introduced into the existing capacity calculation formula. This parameter is evaluated using normal, exponential, and empirical distributions constructed from an observation sample. A comparative analysis is performed to assess the influence of different delay modeling approaches on the actual capacity of the railway section. The results demonstrate that accounting for stochastic delays leads to a reduction in the calculated capacity compared to deterministic estimates and provides a more realistic representation of operational train movement conditions. Particular attention is given to the tail behavior of delay distributions, which has the most significant impact on timetable stability and operational performance. The proposed approach ensures the reproducibility of capacity calculations and can be adapted to various railway line configurations and train interval control systems. The findings confirm the relevance of applying a stochastic approach in railway capacity assessment.

10.48081/BGQF1933

2026

Issue 1