Theory and Practice of Metallurgy

On the 100th Anniversary of the Department of Electrometallurgy

K.M. Sukhyy — 2025-02-21

The article reflects the origin and development of the electrometallurgical industry in Ukraine. The emphasis is placed on the role of the Department of Electrometallurgy at the Dnipro Metallurgical Institute in this process. The Department of Electrometallurgy was established in 1925. This was facilitated by the leading role of scientists, professors, doctors of technical sciences Telnyi S. I., Khytryk S. Y., Hasyk M. I., who made a significant contribution to the development of the electrometallurgical industry in Ukraine and the training of highly qualified specialists. In the article, the key stages of formation and development of electrometallurgy have been outlined, and the crucial role of scientists and teachers of the Department has been stated.

Microwave processing of materials in metallurgy

M.M. Gasik — 2025-02-21

The application of microwave technology in minerals processing and metallurgy is getting interest as it allows non-conventional treatment of depleted resources and has positive environmental and economic impact. Microwave processing provides rapid and selective heating with energy efficiency, in contrast to traditional methods. This work analysis some basic features of this technology and shows examples of modelling and experimental study of hybrid microwave treatment of oxide materials, highlighting differences in achievable temperatures and heating times. The model for experimental hybrid microwave furnace with cavity resonating in TM₀₁₂ mode at 2.45 GHz with 2 kW power has been implemented in COMSOL software and tested on heating of zirconia samples with SiC based susceptor. Electric field and temperature distributions have been simulated and heating rate variations analysed in different positions of the cavity. Results of the analysis are discussed together with the potential use of microwave technology in ore treatment, mineral processing, smelting and carbothermic reduction. This technology has a very good potential in enhancing metal recovery, reducing energy consumption, and improving processing, but this requires understanding about how different materials reacts with microwaves and how the furnaces have to be optimized for a better sustainability.

The-state-Art of steelmaking technology based on hydrogen metallurgy

ZhouHua Jiang — 2025-02-21

This paper puts forward the viewpoint that “hydrogen steelmaking” replaces “oxygen steelmaking”, and summarizes and evaluates the research status of “hydrogen steelmaking”. Hydrogen metallurgy steelmaking has unique advantages in energy saving, consumption reduction and product quality improvement. On the one hand, hydrogen has a highly efficient melting effect, which can effectively reduce the energy consumption of steelmaking. “Hydrogen” in plasma state has the characteristics of high temperature and high thermal conductivity, which can be used as a highly efficient heat source to realize the melting of charge and heating of steel, and has been applied in steelmaking processes such as EAF, converter and tundish. Blowing gaseous “Hydrogen” can accelerate the homogenization in the composition and temperature, and the movement of hydrogen bubbles can be adhered to the non-metallic inclusions which can be accelerated to float out. At the same time, hydrogen reacts with oxygen in the liquid steel to release a large amount of heat, which improves the thermodynamic and kinetic conditions of the melt pool reaction. In addition, “Hydrogen” can inhibit oxidation and reduce the loss of Cr, Mn and other alloying elements by creating a reducing atmosphere. On the other hand, “Hydrogen” has a non-polluting refining effect that significantly improves the cleanliness of the steel. Based on the high activity and high reducibility of “Hydrogen”, “Hydrogen” can effectively remove impurity elements such as O, C, N, S and P in steel, especially “Hydrogen” in plasma state, which can directly react with the impurity elements to generate H₂O, CH₄, NH₃, H₂S and PH₃ and other gaseous products that are easy to be volatilized and removed, so as to avoid the formation of non-metallic inclusions, and to realize the highly efficient and high-cleanliness steelmaking with “zero inclusions”. Therefore, the development of a new generation of green, near-zero carbon, “zero inclusion” and pollution-free steelmaking process using “hydrogen” instead of “carbon” will accelerate the green, high-quality, and sustainable development of the steel industry.

Ukrainian steel and ferroalloys in 2022-2024: how russian aggression has impacted on the work of the country's metallurgical industry

S.G. Gryshchenko — 2025-02-21

This article analyzes the state of the Ukrainian metallurgical industry, particularly steel and ferroalloy production, between 2022 and 2024, emphasizing the significant impact of the full-scale russian aggression. It highlights the industry's successes in 2021, when growth in steel and ferroalloy production was driven by favorable market conditions. The consequences of the russian invasion are detailed, including territorial occupation, infrastructure destruction, challenges with logistics and raw materials, and a shortage of qualified personnel, which led to a threefold reduction in steel production in 2022 and a substantial decline in ferroalloy output. Statistical data for 2022-2024 is presented, showing a gradual recovery in steel production volumes and a continued decrease in ferroalloy production, even leading to plant shutdowns in the fourth quarter of 2023. Special attention is given to the measures undertaken by Ukrainian enterprises to adapt to the new circumstances, including reorienting towards alternative raw material sources and optimizing electrotechnological regimes. The systemic problems facing the industry are highlighted: proximity to conflict zones, high electricity tariffs, personnel shortages, and logistical difficulties. In the context of Ukraine's European integration and its commitment to "green metallurgy," the prospects for the recovery and development of the domestic metallurgical sector are discussed, including projects for direct reduced iron and "green" steel production. Ukraine's potential to become a key supplier of "green" metallurgical raw materials for Europe is underscored.

Some aspets in the electric arc steelmaking production

M. Karbowniczek — 2025-02-21

The electric arc furnace (EAF) is the initial aggregate and the key point in many carbon steel and in most stainless-steel melting plants. In the article new solutions in construction, technology, operations and control, used in modern steelmaking plant, will be presented. On literature background the results of author’s investigation in electric steelmaking area will be showed. Special attention will be paid on the foaming slag technology used for thermal efficiency increase which means a low cost operation. New elaborated and patented method of stainless-steel slag foaming technology will be described. With slag foaming is connected the optimization procedure concern on minimum the electrical energy consumption and tap-to-tap time. Industrial application in this area will be presented. As a separate chapter the solution in environmental protection during EAF production will be described.

Decarbonisation challenges for steelmaking and scrap recycling role

G.P. Stovpchenko — 2025-02-21

This article discusses the challenges the steelmaking industry faces in striving to achieve competitive alternatives and potential solutions in response to the imperatives of decarbonization and zero-waste manufacturing. Expanding scrap recycling is a logical practical solution that the steel industry must pursue to effectively reduce its carbon emissions amidst its current structure. One of the steps towards achieving this is by utilizing alternative scrap sources to enhance iron recovery. The Recovery Slagged Scrap (RSS) from steelmaking includes metal pieces covered by low-conductive slag, which changes its melting behaviour. Analysis of trials results has shown that adding RSS to BOF iron-bearing charge mix can speed up the formation of primary slag and at proper consumption does not pose technological difficulties. Utilizing RSS as a coolant or slag-forming addition may improve the melting process and provide cost reduction of a charge mix for a steelmaking facility.

Research of the ore reducing furnaces electrical modes for ferronicel production

D.V. Shevchenko — 2025-02-21

The paper presents the results of a study of the electrical modes of ferronickel furnaces OTF-1 and OTF-2 at the Pobuzhsky ferronickel plant. It was found that the furnaces operate in arcless mode. An asymmetrical voltage mode is observed: electrode casing - under, which indicates an unbalanced mode of the furnace. As a result of measurements, a significant transfer of power was detected in the area of the electrical circuit of the 4th, 5th, 6th electrodes. An analysis of the electrical mode of a 48 MVA round ferronickel furnace in the city of Hua-Hua (China) showed that the use of a furnace transformer without a voltage booster and an autotransformer makes it possible to provide the necessary electrical mode of ferronickel furnaces. An analysis of the electrical mode of a 90 MVA round ferronickel furnace in Guatemala showed the possibility of operating these furnaces in a combined mode, i.e. in the presence of an electric arc, which is controlled by the resistance of the electrodes and the power ratio in the electric arc and slag.

Laboratory studies on the effect of vibro-impact action of the screening surface on the main technological indicators of metallurgical raw material screening

V.Y. Zaselskyi — 2025-02-21

The article presents the results of a study on the effect of vibro-impact action of the screening surface on the main technological indicators of metallurgical raw material screening. The screening process is one of the key technological operations in the preparatory processes of metallurgical production, as it directly influences the quality of raw material fractionation and process productivity. The issue of screen aperture clogging significantly limits the efficiency of screening, leading to a decrease in the quality of prepared charge and an increase in energy costs. The purpose of the study is to investigate the effect of vibro-impact action of the screening surface on aperture clogging and the productivity indicators of metallurgical raw material screening. To achieve this goal, a laboratory model of a vibratory screener was developed, allowing for the simulation of various vibration modes of the box and studying their impact on the raw material screening process. The research methodology included a series of experiments with varying amplitude and angular frequency of box oscillations, analysis of the results using mathematical statistics methods, and the construction of mathematical models of the dependence of transportation productivity and clogging coefficient on vibration parameters. Experiments were conducted for two types of screening surfaces – fixed and freely laid, which allowed for assessing the impact of vibro-impact loads on screen aperture self-cleaning. The results showed that maximum transportation productivity is achieved at a forced oscillation amplitude of 2·10^-3 m and an acceleration of 28…32 m/s². At the same time, the clogging coefficient significantly decreases at an amplitude of 1.8…2.2·10^-3 m and an oscillation frequency of 94.2…102 s^-1. The constructed mathematical models allow predicting changes in the technological parameters of the process depending on the dynamic characteristics of the box and assist in selecting optimal operating modes for vibratory screeners. The scientific novelty of the work lies in determining the effect of vibro-impact action on the efficiency of metallurgical raw material screening and forming new approaches to reducing screen surface clogging. The practical significance of the study is due to the possibility of using the obtained results to modernize existing screeners and develop new designs with improved technological characteristics, which will contribute to enhancing the efficiency of preparatory processes in metallurgical production.

Physical and chemical audits and comparative analyses of scrap remelting technology indicators for high-alloyed steel with special purposes using the duplex-slag process and the resource-saving mono-slag process

Yu.S. Proidak — 2025-02-21

The goal. The research purpose is a physicochemical audit and comparative analysis of the indicators of the technologies for remelting scrap of high-alloy special-purpose steels using a two-slag process and a resource-efficient single-slag process to create an innovative technology for the electric steelmaking process. Methodology. The research used miscellaneous methods and modern equipment for studying the physical chemistry of metallurgical processes, including optical metallography methods on the “Neophot-24” installation, to assess the microstructure of the metal and the mineralogical composition of the slags. Experimental and industrial smelting was carried out to determine the balance of alloying elements by certified chemical and spectral analysis of the metal and slag. Results and scientific novelty. To ensure the rational composition of the slag of reduced basicity during melting, a mixture with the following composition was synthesized from oxides classified as "chemically pure": 50%СаО-35%SiO₂-5%Al₂O₃-5%MgO-5%FeO. This allows for the reduction of the loss of alloying elements and increases the efficiency of remelting. According to the results of the analysis conducted by the requirements of DSTU 8966:2019 regarding the contamination of the metal with non-metallic inclusions and their crystalline and chemical composition, it was found that the vast majority of inclusions are represented by silicates with a size of 7-10 μm. These indicators depend on the size and conditions of crystallization of the ingot. Changes in the content of alloying elements due to the remelting process were analyzed. It was confirmed that the losses of expensive alloying elements (Cr, Mo, W, V) depend not only on their chemical affinity for oxygen but also on the formation of compounds of the type СаО*МеО in the slag, where МеО oxide has an acidic nature of interaction. New knowledge has been obtained regarding the physical properties and phase composition of lime-iron slag of the CrO-FeO-SiO₂-(Ме)O system where Me-Mn, Cr, V, Mo. The obtained scientific results significantly complement the research of domestic and foreign scientists due to the novelty of the approach and practical orientation to the needs of specific industries. Practical value. The developed technological solutions for predicting the optimal composition of the metal dump for metal scraps of alloyed special-purpose steels will increase the technical and economic performance of steelmaking in electric furnaces and promote the reuse of valuable materials. This is important in the context of the constant increase in the cost of raw materials and efforts aimed at reducing the impact on the environment, as well as on the sustainable development of Ukraine (solving environmental problems, reducing greenhouse gas emissions, reducing the consumption of ferroalloys, etc.).

Research on the properties of ferronickel production slags and development of technological schemes for their enrichment

D.V. Shevchenko — 2025-02-21

Objective. Determination of the physicochemical properties of slags, phase composition, and forms of nickel presence in them, development of enrichment modes and equipment parameters. Research Methods and Equipment. X-ray spectral microanalysis (RSMA) on the SELMI REM-106I installation was used to determine the distribution of nickel between the metallic and oxide phases in the presented slag samples. Dry and wet gravity and magnetic separation using modernized magnetic separators established the possibility of slag enrichment and the distribution of nickel between the enrichment products. Research Results. This work has conducted research on the gravitational-magnetic separation of electro-furnace and refining slags of ferronickel production in the conditions of the Pobuzhsky ferronickel plant. The efficiency of implementing the developed technological schemes in production was shown, providing additional extraction in the amount of 119 tons or 9.8% of the total annual nickel production at the plant. Slag samples were ground in experimental ball mills to fractions of –0.16; 0.16¸1.6 and +1.6 mm and subjected to enrichment by gravity and magnetic separators with a magnetic induction on the drum surface of 0.3-0.6 T (Tesla) of the MBS-300 and MS-500 types with a total metal phase yield of up to 30%. Scientific Novelty. RSMA established that nickel, both in electric furnace granulated slags and in refining slags, is in the metallic phase and is represented by metal nuggets in combination with iron of various shapes and sizes. Enrichment of electric furnace and refining slags by a combined method using a high-intensity magnetic field will allow obtaining a metal concentrate containing 0.9-38% nickel. The combined enrichment method using high-intensity magnetic separators is one of the most promising for enriching both primary mineral raw materials and secondary materials of ferrous and non-ferrous metal production. Practical Significance. The developed and proposed for implementation technological schemes for enrichment of electric furnace slags using the “wet” technology and refining slags using the “dry” technology allow for the utilization of about 1200 tons of nickel per year or the extraction of 31.6% and 94.65% of nickel from slags, respectively.

Regularities of solid-phase reduction of iron oxides under conditions of combined chemical-catalytic and energetic influence

O.M. Grishin — 2025-02-21

Purpose. The purpose of the work is a physicochemical analysis of the intensification of the process of solid-phase iron reduction under the conditions of the joint influence of catalytic additives and an electromagnetic field (EMF). Methodology. The experiments were conducted in an alternating magnetic field with a frequency from industrial to ultrasonic using the thermogravimetric method. The process of reduction of various iron ore materials was studied in the temperature range of 873-1373 К Results. The results of laboratory experiments indicate the influence of the electromagnetic field and intensifying catalytic additives on the process of solid-phase reduction of various iron ore materials. The non-additivity of the results of the joint influence of additives and an intensifying EMF is shown. The study of the influence of various process parameters on the rate and degree of reduction of iron ore materials is carried out. Scientific novelty. The joint intensifying effect of catalytic additives and EMF on the process of solid-phase iron reduction is experimentally shown. A physicochemical justification of the non-additivity of the joint influence on the kinetics of the reduction process is proposed. Practical significance. Intensification of the processes of solid-phase reduction of iron ore raw materials provides a significant increase in the productivity of direct iron production technologies - process intensification and process productivity.

Improved heat-insulating products for ingot hot-tops in molds without extensions

V.V. Akreiev — 2025-02-21

The fundamental principle of proper ingot solidification in metal molds - hop top part of ingot should cool and solidify slowly than the ingot body. To achieve this, typically hop top parts of ingots are insulated with special thermal insulation products. They are mounted either directly on the inner surface of the mold or installed in special hop top extensions of the mold. This approach effectively directs shrinkage defects away from the usable ingot section into hop top cut zone. For different steel grades (alloys), depending of the application, ingot design, and casting method, hop top cut ranges from 8% to 16% of the total ingot mass. This article presents experience in using an advanced thermal insulation insert design, which enables higher part of usable ingot metal, prevents subhead cracks in the ingot, simplify and lighten the lining of ingot hop top.

Promising metal-thermal technologies for titanium production

V.S. Ignatiev — 2025-02-21

This review discusses existing and new titanium production technologies, their advantages and disadvantages. The current global production of titanium metal is based on the production of titanium sponge by reducing titanium tetrachloride with liquid magnesium and then purifying it by electric arc remelting (Kroll's metallothermal method). The Kroll method has some disadvantages: periodicity of the process, low speed, and high cost of raw materials. The paper analyzes a number of fundamentally new technological schemes for titanium production: magnetism in salt melts; magnetism in a liquefied layer of magnesium particles (TIRO process); sodium jet thermionic (Armstrong process); steam process. In the near future, we can expect a breakthrough in titanium technology that will reduce its cost.

Adjusting properties of electrode pitch with fractions of coal tar

A.G. Starovoit — 2025-02-21

The paper presents the investigation results of the organic mass modification of the impregnating pitch of coal tar with low pyrolysis degree. The processes that form the pitch operational properties in the impregnation technology of graphitized electrodes were studied. Specific features of the modifying additive effect on the quality characteristics of the pitch and its group composition were established. Such technological approach makes it possible to intensify the impregnation process of blanks for graphitized electrodes.

Roll drive mechanism with planetary gearbox for cold pilger pipe rolling mills

V.M. Danchenko — 2025-02-21

Purpose. Creation and study of a roll drive mechanism with a planetary gearbox, which will ensure a reduction in axial forces in the production of thin-walled pipes and it will expand the range of pipes obtained on cold pilger rolling mills. Methodology. The work includes research on determining the parameters of the roll drive of cold pilger rolling mills using the graph-analytical method of studying the kinematics of mechanisms. Results. The roll drive mechanism with a planetary gearbox will ensure regulation of the angular speed of rotation of the rolls and a reduction in axial forces. Scientific novelty. The influence of the geometric parameters of the roll drive on the value of the angular speed of the rolls, which ensure a reduction in axial forces, has been determined. Practical significance. The roll drive mechanism with a planetary gearbox allows obtaining high-quality thin-walled pipes with the possibility of expanding the range.

Research into the possibility of producing ferrosilicoaluminum from recycled materials

O.Yu. Taran — 2025-02-21

The technology of electrothermal production of ferrosilicoaluminum using recyclable material from abrasive production has been developed, studied and tested in laboratory and semi-industrial conditions. The following were used as burden components: "old charge" from silicon carbide production, sludge from abrasive electrocorundum and silicon carbide, magnetic fraction from electrocorundum production and gas coal. As a result, an alloy containing 61−69% Al+Si was obtained.