Metallurgical Research Articles

Teaching Aid Regarding the Application of Advanced Organic Petrography in Recycling End-of-Life Lithium-Ion Batteries

This teaching aid aims to illustrate a range of the most common materials in end-of-life (EoL) lithium-ion batteries (LIBs) to demonstrate the usefulness of advanced organic petrography in the characterization of EoL LIB materials and to assess the efficiency of LIB recycling processes from the pre-processing stage up to the impurities of the metallurgical processes. Additionally, it may be useful for students, petrographers, and professionals in battery development and recycling.

Phosphorus removal from steelmaking slag by selective leaching in the steel pickling waste liquor

Steelmaking slag and steel pickling waste liquor (SPWL) are two kinds of by-products in steel plants. The existence of phosphorus (P) in steelmaking slag is the main factor affecting its reuse within the steelmaking process. To remove P from steelmaking slag with a low-cost method, selective leaching was proposed by using SPWL as a leaching agent. SPWL generally contains a small amount of Fe3+ ions, and thus the effect of Fe3+ content in SPWL on the dissolution behavior (especially P element) of steelmaking slag was investigated, as well as the pH value and steelmaking slag type. The dissolution ratios of P from various slags in the SPWL containing 500 ppm Fe3+ exceeded 95 % at pH 1.5 while those of Fe, Mn, and Al were very low, exhibiting satisfied selective leaching of P. Increasing pH value and Fe3+ content (in SPWL) resulted in a decreasing P dissolution ratio while exerting an insignificant effect on the dissolution of other elements. The FeHPO4+ was predicted as the predominant species during leaching and the transformation of FeHPO4+ to FePO4 could be present. When the SPWL containing 800 ppm Fe3+ was used, FePO4 was observed in the residues after leaching at pH 2.0, resulting in a worse removal of P from slag. However, the residues including massive valuable components had an extremely low P content after leaching in the SPWL containing 500 ppm Fe3+ at pH 1.5, which can be used as a flux in the metallurgical process. To ensure a high P removal rate from steelmaking slag and to prevent FePO4 precipitation during leaching, a relatively low pH and Fe3+ content in the SPWL are necessary.

A IMPLANTAÇÃO DA METODOLOGIA 5S EM UMA CÉLULA DE MONTAGEM DE UMA INDÚSTRIA METALÚRGICA

The 5S methodology originates from Japan and is based on the application of five concepts: Seiri, Seiton, Seiso, Seiketsu, and Shitsuke. The 5S method focuses on organizing different sectors of a company based on organization, standardization, cleanliness, and discipline. It is a behavioral improvement program characterized by fostering teamwork, organizing the work environment, preserving employee well-being, maintaining productivity, and emphasizing cleanliness and organization. The objective of this work is to describe the implementation of the 5S methodology through the physical rearrangement in a medium-sized metallurgical industry. The research, characterized as a case study in a company in the interior of the state of São Paulo, is carry out applied and qualitative approach, presenting the implementation of a 5S improvement project through physical rearrangement. The choose of the 5S methodology is due to the fact that consolidating, enhancing, or creating an organizational routine facilitates the adoption of the studied concepts in a real case within a medium-sized industry that manufactures and sells fitness equipment. The implementation of the 5S program began with the approval of the management, achieved through awareness demonstrated by photographic evidence showing the current status of the company. This project’s implementation was necessary due to the evident problems arising from a lack of organization, cleanliness, and the conditions where the products were found in the sector. Its implementation led to a significant improvement in production processes in terms of quality, efficiency, and productivity, as well as enhancements in visual aspects and workplace conditions. It can be concluded that the 5S Program is a simple philosophy that is easy to implement, but its results entirely depend on the level of engagement of the people involved. Although challenges exist in the implementation process, particularly of a behavioral nature, technical improvements were also observed, resulting in a more positive work environment and a more efficient industrial routine. Despite still having many actions to be taken, it is considered that the 5S Program was successful in its implementation.

Heat-resistant concretes based on cement binders and waste from the metallurgical industry

The main direction of the development of heat-resistant concrete production is the use of new materials, ensuring mechanization and industrialization of construction, increasing the performance characteristics of refractory compositions, reducing material consumption, introducing waste-free technologies in the production of concrete with increased physical and mechanical characteristics under prolonged exposure to high temperatures on cement binders and waste from the metallurgical industry and reducing environmental pollution. A significant environmental impact on the environment is exerted by large-tonnage technogenic waste produced by JSC «Aluminum of Kazakhstan» – bauxite sludge obtained by processing bauxite into alumina containing 42.7% Fe2O3. The prospects of its application as a filler in heat-resistant concretes are considered, which makes it possible to increase the physico-mechanical and thermal characteristics. The composition and properties of this waste and the change in the properties of heat-resistant concrete during the introduction of filler have been studied. Reactive alumina has been studied, which is 99.9% submicron alumina with a very low content of Na2O oxide. It is shown that the properties of concrete change after the introduction of iron-containing waste in the amount of 5% and reactive alumina – 37.5% and 38.8%. Their volumetric weight, control strength, and other properties are increased. The improvement of physical, mechanical, and thermal characteristics depends on the structure and neoplasms in the obtained samples. Samples of heat-resistant concrete were analyzed using electron probe X-ray spectral qualitative and quantitative microanalysis and X-ray fluorescence spectrometry and it was shown that the iron-alumina waste contributes to the compaction of the structure due to its resistance to delamination and has increased fluidity at low humidity in the cementing mass. For further investigation of the physical-thermal characteristics, depending on the structure and neoplasms in the obtained samples, a petrographic method using a polarization microscope in transmitted and reflected light is required.

Manufacturing production as a source of growth: the case of Portugal

The aim of this paper is to test the relationship between manufacturing production and economic growth in Portugal from the 1950s to the present day, following Nicholas Kaldor’s (1908–1986) thinking, which assumes that manufacturing is the true engine of the economic activity of a country. By estimating a series of econometric models, including a Vector Autoregressive (VAR) model, it was possible to identify a positive relationship between growth and manufacturing production since the 1950s. The results also show that each increase of 1 percentage point (pp) in real growth rate of the production of basic metallurgical industries and manufacture of metallic products in a certain year t−1 for the period 1956–2019, caused an increase of 0.07 pp in the Portuguese economic growth during a following year t on average. We hope that these findings will stimulate new and interesting research regarding the important issues of manufacturing production and economic growth.

Modeling Freeze‐Lining Formation: A Case Study in the Slag Fuming Process

Slag fuming (SF) is a metallurgical process designed to recycle Zn‐containing slags derived from various industrial residues. To protect the reactor from corrosive molten slag, a deliberate as‐solidified slag layer, known as a freeze lining (FL), is formed on the reactor walls using intense water‐cooled jackets. In this article, a computational‐fluid‐dynamics‐based model capable of simulating FL formation in a SF furnace is presented. To capture the complex multiphase flow dynamics, heat transfer, and FL formation during SF, a volume‐of‐fluid model is coupled with a mixture continuum solidification model. Three phases are considered: gas, liquid bulk slag, and solid slag (FL). Moreover, two types of FL are distinguished: one that solidifies on the reactor wall in the bulk slag region and another that solidifies on the reactor wall in the freeboard region owing to slag splashing. Comparisons between calculated FL thickness and heat fluxes and corresponding industrial data demonstrate satisfactory agreement. In this outcome, the robustness of the model is underscored and confidence in its accuracy is instilled. In the simulation results, valuable insights are provided into the evolution of the fuming process, particularly regarding the slag bath temperature, slag splashing dynamics, FL formation, local heat fluxes through the reactor wall, and global net energy balance.

Prediction model of permeability index for blast furnace based on WD-NL-transformer

The permeability index is an important variable to reflect the operating state of a blast furnace quickly, intuitively and comprehensively. Given the multi-scale, nonlinear and massive characteristics of the blast furnace smelting process data, a prediction model of permeability index based on the WD-NL-transformer (wavelet de-noising-nonlinear-transformer) method was proposed. The key variables affecting permeability index were selected from multiple perspectives by Pearson correlation coefficient and copula entropy. The extreme outliers were optimised using box plots and Lagrange linear interpolation. A data set was constructed after wavelet de-noising to build the prediction model with nonlinear processing capability, time-series prediction capability, and early stopping method. The results show that the MSE of WD-NL-transformer is 0.0093, with the RMSE of 0.0086. Meanwhile, the R2 is 0.9859, and the running time is 19.59 s, which means the model has great prediction accuracy and inference speed. The proposed model could provide theoretical support for advanced control of permeability index, which is of practical significance to ensure the stability of blast furnace smelting and accelerate the metallurgical process of intelligent automation.

CO2 plasma inducing steel-slag with active sites for efficient growth of carbon nanotubes for the high-performance microwave absorption

As a solid waste generated in the metallurgical process, the highly efficient catalysis of steel-slag for carbon nanotube (CNT) growth remains a huge challenge. Herein, a CO2 plasma-inducing approach for modifying the steel-slag catalyst with rich active sites was developed for CNT growth in the chemical vapor deposition (CVD) process. Furthermore, the high-energy CO2 plasma refines the particles on the steel-slag surface, reducing the particle size on the surface of steel-slag effectively increasing the active sites of the catalyst. In addition, the thermal effect generated by the gas molecule ionization process under CO2 increases the background temperature of the steel-slag, and the interaction between the oxygen-active substances produced and the iron oxide on the surface of steel-slag undergoes an oxidation reaction upon full contact with high-energy particles, which greatly improves the catalytic efficiency of the steel-slag as a catalyst for CNT, and increases the catalytic efficiency by 50 % compared with the non-plasma modified steel-slag as a catalyst for catalyzing CNTs. In addition, catalytically grown CNTs encapsulate magnetic steel-slag catalysts to form a three-dimensional CNT network structure, with high-performance electromagnetic wave absorption. The composite absorbing material with a thickness of only 3.55 mm has a minimum absorption rate of −64.08 dB for electromagnetic waves at a frequency of 7.9 GHz. The dielectric and the magnetic loss of steel-slag lead to enhanced electromagnetic wave absorption. Therefore, this study provides an inexpensive and environmentally friendly idea for the design of high-efficiency CNT growth and solid waste catalyst modification synthesized with high-performance absorbers.

Simulation-Based Design for Recycling of Car Electronic Modules as a Function of Disassembly Strategies

Modules (or parts) of a car are a complex functional material combination used to deliver a specified task for a car. Recovering all materials, energy, etc., into high-grade materials at their end of life (EoL) is impossible. This is dictated by the second law of thermodynamics (2LT) and thence economics. Thus, recyclability cannot be conducted with simplistic mass-based approaches void of thermodynamic considerations. We apply, in this paper, a process simulation model to estimate the true recyclability of various SEAT (Volkswagen Group) car parts within the EU H2020 TREASURE project. This simulation model is developed with 190 reactors and over 310 feed components with over 1000 reaction species in the 880 streams of the flowsheet. The uniqueness of the work in this paper is to apply the full material declaration (FMD) and bill of materials (BOM) of all 310 materials in the parts as a feed to the process simulation model to show the parts’ true recyclability. We classified all parts into categories, i.e., copper-rich, steel-rich and plastic-rich, to maximally recover metals at the desired material quality, as well as energy. Recyclability is understood to create high-grade products that can be applied with the same functional quality in these parts. In addition, disassembly strategies and related possible redesign show how much recyclability can be improved. Process simulation permits the creation of alloys, phases, materials, etc., at a desired quality. The strength of the simulation permits any feed from any End-of-Life part to be analyzed, as long as the FMD and BOM are available. This is analogous to any mineral and metallurgical engineering process simulation for which the full mineralogy must be available to analyze and/or design flowsheets. This paper delivers a wealth of data for various parts as well as the ultimate recovery of materials, elements, and energy. The results show clearly that there is no one single recycling rate for elements, materials, and alloys. It is in fact a function of the complexity and material combinations within the parts. The fact that we use a thermochemical-based process simulator with full compositional detail for the considered parts means full energy balances as well as exergy dissipation can be evaluated. This means that we can also evaluate which parts, due complex mixtures of plastics, are best processed for energy recovery or are best for material and metal recovery, with thermochemistry, reactor technology and integrated flowsheets being the basis.

Mullite–Silicate Proppants Based on High-Iron Bauxite and Waste from Metallurgical Industry in Kazakhstan

Mullite–Silicate Proppants Based on High-Iron Bauxite and Waste from Metallurgical Industry in Kazakhstan

High-Temperature Creep Resistance of FeAlOY ODS Ferritic Alloy.

A significant effort in optimizing the chemical composition and powder metallurgical processing led to preparing new-generation ferritic coarse-grained ODS alloys with a high nano-oxide content. The optimization was aimed at high-temperature creep and oxidation resistance at temperatures in the range of 1100-1300 °C. An FeAlOY alloy, with the chemical composition Fe-10Al-4Cr-4Y2O3 (wt. %), seems as the most promising one. The consolidation of the alloy is preferably conducted by hot rolling in several steps, followed by static recrystallization for 1 h at 1200 °C, which provides a stable coarse-grain microstructure with homogeneous dispersion of nano-oxides. This represents the most cost-effective way of production. Another method of consolidation tested was hot rotary swaging, which also gave promising results. The compression creep testing of the alloy at 1100, 1200, and 1300 °C shows excellent creep performance, which is confirmed by the tensile creep tests at 1100 °C as well. The potential in such a temperature range is the target for possible applications of the FeAlOY for the pull rods of high-temperature testing machines, gas turbine blades, or furnace fan vanes. The key effort now focuses on expanding the production from laboratory samples to larger industrial pieces.

Modelling and experimental study on pipeline defect characterisations using a pulsed eddy current measurement

ABSTRACT Pipelines are widely used as the main transportation method in petrochemical and metallurgical industries. However, the special nature of the materials transported in pipelines means they are often subjected to high temperature, high pressure and corrosive conditions. This can lead to defects, such as thinning and cracking, resulting in pipeline failure and causing serious economic losses. Therefore, regular non-destructive testing of pipelines is particularly important. This paper uses the non-destructive testing method with pulsed eddy current technology to characterise pipeline thinning and defects. A preliminary study is conducted on the pulsed eddy current detection signal patterns for pipeline crack defects with varying orientations and quantities. A more portable pulsed eddy current detection device with an extended wall thickness detection range is developed. It can achieve measurements with a maximum thickness of 30 mm for detections of pipelines with rectangular defects and thickness-stepped reduced. The experimental results are consistent with modelling results, and the accuracy for pipelines with insulation layer is also investigated. On-site measurements using the PEC system are conducted on equipment sections with pipe thickness within 20 mm in a petrochemical plant. It is confirmed that the developed PEC inspection device can accurately characterises the thickness of pipelines with 0–50 mm cladding.

A review of in-situ high-temperature characterizations for understanding the processes in metallurgical engineering

A review of in-situ high-temperature characterizations for understanding the processes in metallurgical engineering

Oxygen Content Control in the Electroslag Remelting Process: An Incremental Learning Strategy Based on Optimized Wasserstein Generative Adversarial Network with Gradient Penalty Data Augmentation

Electroslag remelting (ESR) is essential for producing high‐end special steel, but its complex process and numerous influencing factors make quality control challenging. This study addresses oxygen content control during ESR using a big data machine learning approach. An incremental learning strategy is proposed based on an optimized Wasserstein generative adversarial network with gradient penalty (WGAN‐GP) for data enhancement, focusing on G20Cr2Ni4A bearing steel. The WGAN‐GP model enhances time‐series data and metadata, utilizing long short‐term memory networks, fully connected networks, and attention mechanisms. The effectiveness of data enhancement is verified using a deep neural network classifier and statistical methods. Data is divided into historical and data streams, with an incremental learning strategy based on histogram gradient boosting regression trees to prevent catastrophic forgetting and improve efficiency through knowledge distillation and real‐time hyperparameter adjustment. Results show that the data augmentation method significantly improves model generalization and accuracy in small sample metallurgy. The incremental learning strategy enhances prediction accuracy for oxygen content, contributing to better cleanliness quality of electroslag steel. This study offers a novel approach for addressing small sample challenges in metallurgical processes.

Problems and solutions to protection of carbon-graphite electrodes

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.

Development of an application for training management of the maintenance team in a metallurgical industry in the suape industrial complex – cabo de Santo Agostinho

This work presents the development of an application designed to complement traditional training management methods within an organization. The application, developed on the PowerApps platform using a Low-Code approach, aims to facilitate the monitoring and management of employee training in the maintenance department of a company located in the Suape industrial complex, Cabo de Santo Agostinho. Its main objective is to provide a digital platform that allows for the verification of the training status of maintenance technicians, identifying which are in "Attention," "Expired," and/or "OK" status. Traditionally, this data is managed manually, in a time-consuming and error-prone process. The transition to a digital system ensures data accuracy, reduces the time required to access and update information, and improves the overall efficiency of the department's activity scheduling process. During the testing phase, conducted between January and August 2024, comparative data was collected on the training consultation process, before and after the implementation of the application. Preliminary results indicated a significant improvement in the efficiency and productivity of the maintenance department, comparable to other works that used PowerApps as a quick and low-cost solution.

Thiosulfate leaching in carbonaceous gold-bearing ores in Ethiopia

One of the main unit operations in metallurgical processing plant designs is gold leaching. The traditional cyanidation process was chosen and is currently in widespread use. However, the mining sector is looking for lixiviants other than cyanide. Cyanide’s effects on the environment have made it difficult for humans and other biotic creatures to survive. There is now research to discover a substitute for this cyanide. It is currently argued that thiosulfate is a preferable substitute for cyanide. The effectiveness of thiosulfate as a leaching agent in carbonaceous gold-bearing ores in Ethiopia is discussed in this paper compared to cyanide. The study has looked into the advantages of employing thiosulfate over cyanide from a technical, and economic standpoint. The leaching effects of both lixiviants on carbonaceous gold-bearing ores extracted from MIDROC Legadembi Open Pit mine in Southern Ethiopia, Oromia region, were examined in a laboratory experiment. After 48 h of leaching, it was discovered that thiosulfate has a better and quicker recovery of 91.54% over 61.70% of cyanide recovery. Tables and graphs are used to demonstrate thiosulfate’s technical advantage over cyanide. As a result, this paper provides evidence regarding the Legadembi gold mine in Ethiopia’s amenability to thiosulfate leaching on carbonaceous gold-bearing ores. A further research perspective is also sought for thiosulfate leaching in other refractory ores.

Selective recovery of platinum from spent catalysts to fabricate platinum/amorphous manganese oxide/corrugated silica carrier for formaldehyde removal

The efficient recovery and reutilization of spent Pt catalysts have two huge challenges in the metallurgical and chemical industries. Herein, platinum was selectively retrieved from spent Pt/γ-Al2O3 catalysts by a microwave-assisted aqua regia digestion strategy, and the as-obtained platinum extract was utilized to prepare a novel Pt/amorphous MnOx/corrugated silica carrier (Pt/MnOx/CSC) catalyst for formaldehyde removal. To decrease consumption of toxic aqua regia, the γ-Al2O3 in the spent catalysts was converted to chemically stabile α-Al2O3 via high-temperature calcination. The high Pt leaching efficiency of 98.31% was achieved at a digestion temperature of 110oC and aqua regia concentration of 40vol%. However, the high leaching temperatures and aqua regia concentrations caused the part dissolution of α-Al2O3, and thus decreased the Pt leaching efficiency. The CSC in the Pt/MnOx/CSC catalysts served as a support, while both the Pt nanoparticles and amorphous MnOx microspheres acted as active catalysts. The synergistical effects between the Pt and amorphous MnOx endowed the composite catalysts with excellent catalytic activity, and the HCHO removal efficiency reached 100% even after five cycle tests. On the one hand, the nanostructured MnOx microspheres provided great surface areas and rich oxygen vacancies for heterogeneous catalysis. On the other hand, the Pt nanoparticles not only enhanced the low-temperature reducibilities of MnOx, but also decreased the apparent activation energies of HCHO catalytic oxidation. This work provided a new strategy for the selective recovery of platinum from spent catalysts and the reutilization of Pt-based catalysts for the HCHO thermal catalytic oxidation.

Стратегические перспективы развития отрасли цветных металлов: проблемы и задачи отечественных производителей

The non-ferrous metallurgy industry in Russia is undergoing profound changes due to geopolitical shifts, the transition to green energy, and the need to develop processing industries. Non-ferrous metals, as strategically important products, can play a decisive role in achieving the global goals of the Russian economy related to economic security, the development of domestic markets, the reconstruction of high-tech industries, the modernization of stably functioning industries, and the improvement of the quality of life for the population. The purpose of this research is to study the trends and risks affecting non-ferrous metal producers and to assess the opportunities and challenges for developing both external and domestic markets, ultimately aiming to ensure sustainable demand for the products of mining companies and metal producers. The primary research methods used include general scientific approaches such as comparative analysis, synthesis, and decomposition. This paper reviews the current state of Russia's non-ferrous metallurgy sector and explores its development prospects, with a specific focus on Norilsk Nickel, a key player operating in the Arctic. The main results of the study include an assessment of the current global market for non-ferrous metals, their role in the energy transition, and the formation of a low-carbon economy. The study also analyzes and summarizes the challenges facing domestic non-ferrous metallurgy and suggests potential directions for its development in the current economic context. A critical analysis of the Strategy for the Development of the Metallurgical Industry of the Russian Federation for the Period up to 2030 reveals that several important aspects and issues are not adequately addressed in the document. For example, it lacks a strategic planning methodology and fails to consider the specific characteristics and potential of the Arctic’s non-ferrous mineral resource base. The practical significance of this study lies in clarifying the prospects for utilizing non-ferrous metals to support the revitalization of high-tech industries in the national economy.

УТИЛИЗАЦИЯ МЕТАЛЛИЧЕСКОГО ПОРОШКА ВЫСОКОУГЛЕРОДИСТОГО ФЕРРОХРОМА МЕТОДОМ САМОРАСПРОСТРАНЯЮЩЕГОСЯ ВЫСОКОТЕМПЕРАТУРНОГО СИНТЕЗА (СВС)

This article discusses the methods of recycling high-carbon ferrochrome metal powder by self-propagating high-temperature synthesis. The article is devoted to the study of aspiration metal dusts formed during the production of ferroalloys. The article analyzes the composition of the source material, its physicochemical properties, and the impact on the testing process. The publication touches upon the relevance of this topic and the advantages of the self-propagating high-temperature synthesis method. Particular attention was paid to comparative analyses of this method from other traditional material processing processes. This article will help to consider the problem of environmental pollution and the impact of traditional metallurgical processes on the ecosystem. The authors also analyze in detail the physical properties of the original powder samples and their combustion temperature mode. The publication shows the process flow charts, laboratory devices, and the type of resulting material. This article provides a detailed analysis of the types of laboratory devices, their physical and mechanical properties. The publication provides a thorough and detailed chemical analysis of the resulting material. In the course of the study, the expected results were obtained, which are presented in the form of tables and a figure. The article consists of an introduction, main part, conclusion, conclusion and list of references.