The article examines the degradation of the organic phase during the solvent extraction of copper using L-SX-EW technology, as well as methods for maintaining its process efficiency. It is shown that the operation of oxime extractants leads to the accumulation of chemical degradation products and surfactants, resulting in poor phase separation and the formation of stable emulsions (crud). The study analyzes primary approaches to organic phase treatment, specifically the use of natural sorbents such as bentonite and diatomite. Laboratory experiments were conducted to treat the organic extractant with these adsorbents to evaluate their impact on the state of the organic phase. It was established that the use of mineral adsorbents can facilitate the removal of some contaminants generated during extractant operation. Bentonite, particularly after acid activation, was found to provide a significant reduction in the content of contaminants and improve the condition of the organic phase. Meanwhile, diatomite demonstrated relatively low sorption capacity and limited efficiency under the studied conditions. The findings are of practical importance for increasing the stability and operational efficiency of industrial SX-EW plants.

https://doi.org/10.48081/BGQF2239

2026

Issue 2

This paper presents an experimental study on the efficiency of aluminum dross processing using a drum separator for metallic aluminum recovery. The granulometric composition and distribution of the metallic phase across separation products were analyzed. The results show that the majority of metallic aluminum is concentrated in the coarse fraction (+6.5 mm), where its content reaches 85–90%, while in the fine dust fraction (–0.5 mm) it does not exceed 5%. The actual material distribution was 29.4% for the coarse fraction, 47.8% for the medium fraction, and 22.8% for the dust fraction. Chemical composition analysis of the initial dross revealed a high aluminum content of up to 58%, including up to 38% metallic aluminum, indicating significant recovery potential. It was established that mechanical separation ensures effective concentration of the metallic phase, redistribution of aluminum among fractions, and reduction of metal losses in fine particles. The obtained results confirm the technological efficiency of the drum separator and justify its application in combined aluminum dross processing technologies aimed at improving resource and energy efficiency in metallurgical production.

https://doi.org/10.48081/BGQF2219

2026

Issue 2

This article presents the results of a study of the tribocorrosion resistance of 30KhGSA alloy steel after diffusion thermocyclic electrolytic-plasma boriding (DTEPB). The aim of the study is to evaluate the influence of DTEPB parameters on the formation of the surface layer structure and its behavior under tribocorrosion conditions. The study utilized tribocorrosion tests with simultaneous recording of the friction coefficient and electrochemical parameters, potentiodynamic analysis, as well as scanning electron microscopy and energy-dispersive analysis. It was found that the treatment leads to the formation of a dense boride layer, which significantly increases the material's resistance to tribocorrosion destruction. Optimum characteristics are achieved with a 30% sodium tetraborate content in the electrolyte: the wear rate is reduced to 1.036×10⁻⁴ mm²/N m, and the corrosion rate is reduced to 0.00685 mm/year. It has been shown that increasing the number of thermal cycles reduces the defectiveness of the boride layer and enhances its protective properties. The formation of a two-layer structure (oxide and boride layers) reduces the friction coefficient and limits the development of tribocorrosion processes. The obtained results confirm the effectiveness of DTEPB as a method for increasing the tribocorrosion resistance of alloy steels.

https://doi.org/10.48081/BGQF2228

2026

Issue 2

With the deteriorating quality of manganese raw materials and the predominance of iron-manganese ore in Kazakhstan's resource base (up to 70% of total reserves), the development of effective processing technologies is particularly relevant. This paper presents the results of laboratory studies on the selective extraction of iron and the production of rich manganese slag from iron-manganese ores via a carbothermic method using screened special coke as a reducing agent. It was found that, under optimal process parameters, effective separation of iron and manganese is achieved, forming a metallic phase containing up to 93.2% Fe. This process produces manganese slag with a Mn content of up to 38.3% and Fe of 0.68%. The resulting rich manganese slags are characterized by a high Mn/Fe ratio (12÷66), indicating their suitability for subsequent use in the production of manganese ferroalloys. This approach ensures the comprehensive use of iron-manganese ores through the simultaneous production of an iron-containing product and manganese slag and can be considered as a promising direction for increasing the efficiency of processing iron-manganese raw materials in Kazakhstan.

https://doi.org/10.48081/BGQF2232

2026

Issue 2

Corrosion of the body is an important problem during the operation and repair of wagons. Cleaning the body of a railway carriage before painting is the most important stage of preparation, ensuring the adhesion of paint to metal, removing rust, old coating, dirt and oils. High-quality cleaning prevents under-film corrosion, guarantees the durability of the paintwork and significantly prolongs the inter-repair life of the car. The article examines the process of gas dynamic cleaning of the metal surface of the railway carriage body. The process of interaction of the gas dynamic flow with the painted surface of the wagon body is considered. It is determined that the velocity of a particle that hits the surface of the body under gas pressure is ultimately determined by the velocity of the gas dynamic flow; the mass of the particle; the location of the particle in the flow; the surface area of the particle As a result, the dependences of the parameters of the flow effect on the old paintwork of the wagon, the actual cleaning speed and the productivity of the process were obtained.

https://doi.org/10.48081/BGQF2242

2026

Issue 2

Premature failure of cutting tools during the machining of difficult-to-machine materials is a major problem in mechanical engineering production, reducing manufacturing efficiency. To address this issue, thermofrictional machining with pulse cooling was proposed as an alternative to conventional machining methods. Although significant progress has been achieved, studies revealed problems on the cutting edges of thermofrictional tools, including crack formation, wear, and fracture. Therefore, this article focuses on improving the wear resistance of thermofrictional tools used in thermofrictional machining with pulse cooling. The cutting mechanism of this method is based on replacing external friction with internal friction by creating a cyclic “heating–cooling” process in the machining zone, which reduces cutting energy consumption. The study found that wear resistance can be improved by surfacing the cutting edges with a high-strength molten material. Experimental results showed that tools surfaced with STOODY M7-G material have a service life 1.5–2 times longer than conventional thermofrictional tools. However, the surfacing method is characterized by high labor intensity and production cost. Therefore, the development of an alternative technological method for improving tool wear resistance during manufacturing is justified.

https://doi.org/10.48081/BGQF2223

2026

Issue 2

The article presents an analysis and program of stability of a closed nonlinear system "FC-BLDC" by the method of phase trajectories. The analysis of nonlinear systems has its own peculiarities in contrast to the analysis of linear systems. First of all, this is due to the fact that the stability of a nonlinear system depends on the initial conditions and external influences: with some input signals, the system will be stable, and with others it loses the property of stability. Since several equilibrium positions may exist for a nonlinear system, stability should be analyzed in the vicinity of each of them. Which complicates the task of research. System stability analysis is the process of determining whether a system will return to its initial state after a change in its parameters or whether it will deviate from it and eventually become unmanageable. System stability is an important property for dynamic control systems because unstable dynamic systems can lead to undesirable or even dangerous consequences. The root criterion determines the stability of the system by the type of transfer function. The dynamic characteristic of the system, which describes the basic behavioral properties, is a characteristic polynomial located in the denominator of the transfer function. By equating the denominator to zero, the characteristic equation can be obtained, the roots of which determine the stability. The most important task in analyzing dynamic control systems is to solve the problem of their stability. The technical concept of stability of automatic control systems refers not only to the stable operation of the technical system in normal modes, but also to the property of “not getting out of control”.

10.48081/BGQF1905

2026

Issue 1

The paper presents a mathematical model of a dual-loop steering mechanism for a mobile robot, based on Ackermann geometry and enhanced with a corrective PD loop compensating for position error. The aim of the study is to improve trajectory tracking accuracy by combining a precise geometric model of the inner loop with adaptive feedback from the outer loop. The work develops kinematic equations of motion, derives relations for curvature and steering angles, and performs a formal stability analysis of the corrective PD controller. The research methodology includes numerical simulation in MATLAB, allowing evaluation of platform dynamics, trajectory tracking performance, position error, and the influence of noise on control stability. To verify the proposed approach, single-loop and dual-loop steering control systems were compared. Simulation results show a significant reduction in the root-mean-square trajectory tracking error when using the dual-loop mechanism. It is demonstrated that the external PD correction ensures control stability and robustness even under Gaussian noise conditions. The obtained results confirm the effectiveness of the proposed dual-loop architecture and its applicability for control systems of mobile robots, autonomous transport platforms, and other mechatronic devices requiring high motion accuracy. The model is computationally simple and can be used both for educational purposes and for implementation in real robotic platforms.

10.48081/BGQF1904

2026

Issue 1

The insufficient substantiation of phase equilibrium analysis results in the underutilization of the extensive thermodynamic information contained in phase diagrams. Using the iron–silicon system as an example, the applicability of the developed methodology for calculating phase equilibrium lines to evaluate the melt structure through the degree of dissociation or association of congruently melting chemical compounds is demonstrated. It is shown that when dissociation of a congruently melting compound occurs in the melt, the newly obtained values of the Bjerrum–Guggenheim osmotic coefficient, accounting for the degree of dissociation or association of this compound in the melt, exhibit a linear dependence. A characteristic feature of the crystallization line of the FeSi compound is the formation of associates, as evidenced by the initially concave shape of the Φᵢ curves. The aim of this study is to identify the regular features of silicon behavior along the crystallization line from the standpoint of the Bjerrum–Guggenheim osmotic coefficient and to derive a universal mathematical expression for predicting the phase composition of alloys at various silicon concentrations through the degree of dissociation (association) of the congruently melting FeSi compound. For the first time, a mathematical expression for the silicon crystallization line in the iron–silicon system is proposed in the form of a semi-empirical Schröder–Le Chatelier equation relating the liquidus temperature to the silicon concentration. Based on the iron–silicon system, a justified selection of the functional form for the analytical description of the silicon crystallization surface is carried out using the Bjerrum–Guggenheim coefficient. Experimental data from the Fe–Si phase diagram are approximated, and the accuracy and applicability range of the obtained model are evaluated. Characteristic features of the silicon crystallization line behavior associated with changes in crystallization mechanisms and component interactions are identified. The obtained results can be used for numerical modeling of crystallization processes and for predicting the properties of iron–silicon alloys. Key words: phase diagram; degree of association (dissociation); phase equilibrium lines; Gibbs energy; Bjerrum–Guggenheim coefficient; phase crystallization fields.

10.48081/BGQF1926

2026

Issue 1

The article presents the results of successful industrial trials of an environmentally safe technology for stabilizing refined ferrochrome slags aimed at solving the urgent problem of their spontaneous disintegration. This phenomenon, caused by the polymorphic transformation of β-2CaO•SiO₂ into γ-2CaO•SiO₂, leads to the conversion of slag into a powdery material, which makes its further use impossible and creates significant environmental risks. Unlike the traditional chemical stabilization method using boron-containing materials, which ensures only a metastable state of the slag, the authors propose a fundamentally different physico-chemical approach. The key idea of the technology is to regulate the basicity of the slag (CaO/SiO₂ ratio) by introducing an additive—expanded clay (keramzite)—into the melt, which shifts the phase composition into a thermodynamically stable region where the formation of unstable dicalcium silicate is excluded. The paper provides a detailed description of the theoretical justification of the method, including equilibrium phase composition calculations, as well as the stages of laboratory studies and full-scale industrial trials. The highest technological efficiency was demonstrated by an out-of-furnace treatment method, which involves feeding expanded clay through a tapping tube directly into the stream of liquid slag during tapping from the furnace. This method ensures intensive mixing and rapid dissolution of the additive (within 3–5 minutes) without any adverse impact on the reduction processes occurring inside the furnace. The implemented technology makes it possible to produce a stable, non-disintegrating lump product with a basicity below 1.4, suitable for commercial use in the construction industry as an aggregate. Thus, the technology not only solves a significant environmental problem related to the utilization of industrial waste but also provides an economic benefit, transforming waste into a marketable product and contributing to the creation of a closed production cycle at ferroalloy plants.

10.48081/BGQF1922

2026

Issue 1