Metallurgical & Materials Engineering Congress of South-East Europe
The Metallurgical & Materials Engineering Congress of South-East Europe is a biannual gathering of scientists, professionals, and specialists from academia and industry, covering all aspects of Metallurgical & Materials Engineering. The Congress aims to present up-to-date research results, new ideas, and innovations, revealing and interpreting industry and society's critical challenges and actively contributing to their solutions. The Congress encompasses a wide range of related topics and presents current views on processing-structure-property relationships, advances in processing, characterization, and applications of modern materials. It also adopts a multidimensional approach where challenges and solutions are placed in a broader context, such as policy, economics, product design, and value chains. At the Congress, the most recent research in metallurgical and materials engineering will be presented, with a focus on creative strategies and solutions that reduce resource and energy consumption, enhance material recovery, reuse, and recycling, and ultimately minimize adverse environmental effects. The event includes keynote speeches, scientific and technical lectures, poster sessions, and technical tours, as well as a comprehensive exhibition and remarkable social events. Special attention will be given to the promotion of young researchers as well as to applied innovations.
Association of Metallurgical Engineers of Serbia
Several researchers are trying to make use of natural products as corrosion inhibitors. Plant scientists have already established the active principles present in most of the plant materials. The active principles form protective film on the metal surface by coordinating with the metal ion through O, S or N atoms of the functional groups present in the active principles. When the active principles are extracted with acids or organic solvents or with water, usually a mixture of several compounds is obtained. It is very difficult and tedious to isolate and purify them. However, a mixture of inhibitors present in the plant extract may show synergistic effect. The main disadvantage of using plants materials as corrosion inhibitors is their instability; they are readily biodegradable. However, this disadvantage can be minimised or avoided by adding some biocides such as N-cetyl-N,N,N-trimethyl ammonium bromide, or some plant materials which by themselves have biocidal property. This type of approach will make the use of plant materials as corrosion inhibitors universal and versatile. Before the 1960s inorganic inhibitors such as zinc, chromate, polyphosphate and nitrite were used as inhibitors. They provided good corrosion protections. However, discharge of such materials has become unacceptable, due to environmental hazards. Between 1960 and 1980, zinc, polyphosphate, phosphonate, polymer and phosphono carboxylic acids were used as corrosion inhibitors. After 1980 molybdate, phosphonates, phosphono carboxylic acids and polymers were used as inhibitors, along with metal ions such as Zn2+. Recent trend is the search for environmental friendly inhibitors, by the researchers. Most of the natural products are non toxic, biodegradable and readily available in plenty. Various parts of the plants – seeds, fruits, leaves, flowers etc have been used as corrosion inhibitors. Several studies have been published on the use of natural products as corrosion inhibitors . weight loss methods are used to measure the corrosion inhibition efficiency of the inhibitors. Electrochemical studies such as polarization study and AC impedance spectra have been employed to investigate the mechanistic aspects of corrosion inhibition. The surface morphology of the protective fims has been analysed by FTIR, SEM, AFM , EDAX and contact angle measurements. These aspects are discussed in this paper.
Corrosion, Coating, and Protection of Materials
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CORROSION RESISTANCE OF METALLIC BIOMATERIALS IN SIMULATED BODY FLUIDS
The field of biomaterials is of immense importance for the mankind as the very existence and longevity of some of the less fortunate human beings. The field of biomaterials is not new and as early as 4000 years back the Egyptians and Romans have used linen for sutures, gold and iron for dental applications and wood for toe replacement but with very little knowledge about the problem of corrosion. Currently, the availability of better diagnostic tools and advancements in the knowledge on materials as well as on surgical procedures, implantology has assumed greater significance and bioimplants are commonly used in dentistry, orthopedics, plastic and reconstructive surgery, ophthalmology, cardiovascular surgery, neurosurgery, immunology, histopathology, experimental surgery, and veterinary medicine. Various classes of materials such as metals, alloys, polymers ceramics and composites have been widely used to fabricate the bioimplants. These implants encounter different biological environments of very different physico-chemical nature and their interaction with the tissues and bones is a complex problem. Corrosion, the steady degradation of materials by electrochemical attack is of great concern particularly when a metallic implant is placed in the aggressive electrolytic environment of the human body. The implants face severe corrosion environment which includes blood and other constituents of the body fluid which encompass several constituents like water, sodium, chlorine, proteins, plasma, amino acids along with mucin in the case of saliva .The aqueous medium in the human body consists of various anions such as chloride, phosphate, and bicarbonate ions, cations like Na+ , K+ , Ca2+, Mg2+ etc., organic substances of low-molecular-weight species as well as relatively high molecular-weight polymeric components, and dissolved oxygen . The biological molecules upset the equilibrium of the corrosion reactions of the implant by consuming the products due to anodic or cathodic reaction. Proteins can bind themselves to metal ions and transport them away from the implant surface upsetting the equilibrium across the surface double layer that is formed by the electrons on the surface and excess cations in the solution.
RESOURCE FROM RECOVERY FGD GYPSUM: ADDRESSING ENVIRONMENTAL RISKS OF HAZARDOUS TRACE ELEMENTS FOR SAFER REUSE
Flue gas desulfurization (FGD) gypsum, a by-product of coal-fired power plants, offers potential for recycling, particularly in the construction industry and agricultural applications. Its abundant availability and favorable physical properties make it an attractive alternative to natural gypsum. However, the presence of hazardous trace elements (HTEs) such as arsenic (As), cadmium (Cd), chromium (Cr), and zinc (Zn) can pose significant challenges for safe reuse. These elements may leach into the environment, especially under certain chemical or physical conditions, leading to contamination of soil and groundwater. This study explores the speciation and leaching behavior of ten HTEs (As, Cd, Cr, Pb, Cu, Ni, V, Zn, Sb, and Co) in FGD gypsum samples collected from power plants in Serbia, aiming to inform strategies for safer recycling and more sustainable waste management. The results indicate that certain elements, notably As, Cd, and Cr, exist in forms that are highly soluble and bioavailable, suggesting a considerable risk of leaching during use, storage, or landfilling. For instance, As is found in easily soluble fractions in concentrations ranging from 19.8% to 32.5%, while Cr shows a particularly high proportion (70.6%–91.3%) in fractions susceptible to release under environmental conditions. Cd also exhibits a high share in soluble form (31.3%–49.4%), further increasing its environmental mobility. While overall leaching tests suggest that FGD gypsum can be classified as non-hazardous waste, the variability in the mobility of individual elements highlights the importance of targeted risk management. Elements such as Cd, As, and Cr fall within medium to high environmental risk categories and require careful monitoring in any recycling or reuse context.
ENERGY EFFICIENCY OF HOT STOVES FOR THE BLAST FURNACE
An analysis of the energy efficiency of two hot stoves for the blast furnace (HBS), was carried out in the HBIS Serbia Steel Plant. Based on the theoretical benchmark heat balance calculation of blast furnace (BF) gas consumption and insight into the current situation, possibilities for improving energy efficiency were identified. Detailed examination was carried out for a full work cycle of HBS.
SIMULATION OF THE IRON TRANSPORT LADLE PREHEATING PROCESS
In iron and steel metallurgy, transport ladles that collect molten iron from the blast furnace and transport it to the mixer for further processing play a critial role in steelmaking. To prevent thermal shock and subsequent cracking of the ladle’s refractory lining, as well as to minimize heat losses prior to tapping, these ladles are subjected to a preheating process. This paper presents a set of simulations aimed at gaining a better understanding of the temperature distribution within the ladle during this process. The program used to simulate preheating conditions is NOVACASTTM which uses finite volume elements for calculation. In addition to predicting the temperature distribution, the study examines the effects of increasing the fuel flow rate and combustion temperature on the preheating process. Raising the combustion temperature from 1200°C to 1500°C resulted in a faster but more uneven temperature distribution during preheating. A similar effect was obtained by increasing the flow rate from 0.1 l/s to 1.0 l/s. In a much shorter time, the ladle heats up faster, while the temperature distribution is more uniform. These findings highlight opportunities to enhance ladle preheating efficiency through improved thermal control and fuel utilization strategies.
DEVELOPMENT OF S500MC GRADE MICROALLOYED STEEL IN HBIS SERBIA HOT STRIP MILL
The object of this paper is development of hot rolled coils of microalloyed S500MC grade steel in 6.00x1500 mm and 12.00x1500 mm dimensions in HBIS Serbia hot strip mill, according to European Standard EN 10149-2:2013. The basis for this development was present experience in production of grade S460MC. First step was design of chemical composition. This modification required the increase of the content of microalloying elements. Second step included modification of parameters of rolling technology (transfer bar thickness, reheating temperature/time etc.). Finally, after cooling and coiling, hot rolled strips were tested by means of tensile testing and Charpy impact toughness. Results show that in all cases yield strength, ultimate tensile strength, elongation and Charpy impact toughness satisfy requirements from EN 10149-2:2013. Also, due to difference in cooling rate for thin (6,00mm) and thick (12.00mm) hot strips, a driving force for nucleation of ferrite grains will be different. Therefore, chemical compositions for the same grade, but different thickness have to be different in order to compensate the lower driving force for ferrite nucleation in 12.0 mm strip. Slightly increased content of Nb and V in 12.00mm hot strip provided good mechanical properties.
Cu-Sn-Pb BIMETALS: PREDICTION OF BRINELL HARDNESS
This paper presents the results of defining the mathematical model which describes the dependence of Brinell hardness (HB) from the most influential input parameters in industrial conditions of conducting the production process of the bi-metal elements which work in oil systems of axial-piston pumps of high-pressure. Mathematical model is defined using the methods of Multiple Linear Regression Analysis (MLRA), with R2=0.726 and significant statistical reliability –VIF<2 and p<0.05, on the one-year statistical sample. Validation of the acquired model was performed using the data from the following year, collected from the process conducted under industrial conditions, rendering the same statistical reliability, with R2=0.759.
MECHANICAL AND BIODEGRADABILITY PROPERTIES OF SYNTHESIZED BIO-MEMBRANES FROM WASTE HEMP FIBERS
In this study, waste hemp fibers were transformed into cationically modified materials through a two-step process. The process began with the collection of agricultural waste fibers after hemp harvesting, followed by a delignification pretreatment, and subsequently, quaternization using the synthesized Deep Eutectic Solvent of chlorocholine chloride and urea. To form the material into membranes, modified fibers were cross-linked under pressure using citric acid as a natural cross-linker. The structural and chemical characteristics of the non-treated fibers (NtHF) and formed membranes were analyzed using SEM and FTIR techniques. The mechanical properties of the membranes were determined by measuring the breaking force and calculating the tensile strength via the Brazilian test method. Biodegradability was assessed by examining the mass loss of membranes composed of unmodified and cationized hemp fibers over 90 days, using a Soil Burial Test (AATCC Test Method 30-1993) in controlled laboratory conditions (24 °C). The results demonstrated a significant improvement in the tensile strength of the synthesized material (2.41 MPa), attributed to the synergistic effect of physical intermolecular interactions within the cationically modified hemp membranes (WCHM) and enhanced cross-linking using citric acid. The newly synthesized membrane showed great potential as a biodegradable material, with the first signs of degradation, reflected by a 25% mass loss, observed after 14 days. A slightly faster degradation rate was noted for non-treated fibers, highlighting the effectiveness of citric acid as a cross-linker.
RADIATION TECHNOLOGY IN THE LIGHT OF POLYMER WASTE RECYCLING
Polymer pollution transcends national boundaries and threatens both human health and the environment. Despite efforts for efficient reuse of polymer waste, the majority of it accumulates in landfills and dumps or is mismanaged and is being dispersed in the environment. The application of ionizing radiation techniques could serve to reprocess and recycle polymer waste. Using a radiation source (gamma, electron beam or X-ray) to irradiate post-consumer plastics enhances their recyclability and facilitates their transformation into new products. Application of radiation technology is promising because it is not a novel one. Irradiated polymers could be found all around, from vehicle tires to hot water pipes and food packaging. Idea is to use irradiation applying different dose rates to gain reform and restructure polymer structure, with the aim to improve its recyclability and reduce the amount of polymer waste. The use of electron beam irradiation to form bridges between polymer strands refers to the process of cross-linking. Polymers degradation occurs after radiation is applied in the opposite way through chain scission, in that process polymers are cut up or ‘degraded’. Radiation can also induce an electric charge on the surface of plastics, making it easier to sort plastic waste more accurately. This improves both the volume and the number of times the waste can be recycled, such as with thermoplastics, which can be melted and reshaped repeatedly. Radiation technology can drive the economic potential of plastic upcycling by enabling the production of upscaled secondary products, like wood-plastic composites (WPC), from plastic waste, rather than downscaled alternatives.
FUEL OPTIMIZATION IN BLAST FURNACES: BURDEN CONTROL AND RAFT MANAGEMENT
This study presents a comprehensive and integrative approach to optimizing fuel consumption in blast furnace operations, with a focus on the interdependence of PCI–Coke fuel ratio, oxygen-enriched air injection, and precise control of the Raceway Adiabatic Flame Temperature (RAFT). Based on the principles of combustion thermodynamics, reduction kinetics, and gas flow through the burden, the work analyzes critical performance indicators such as coke reactivity (CRI), post-reaction strength (CSR), and mechanical properties (M40, M10). The influence of raw material granulometry, burden distribution, moisture, alkalis, and zinc is also evaluated. Findings confirm that maintaining optimal RAFT and high-quality burden conditions enhances energy efficiency, reduces coke rate, and ensures greater process stability, while offering a sustainable pathway for advanced blast furnace management.
AFLATOXIN B1 ADSORPTION BY BENTONITE AND COMPOSITES WITH CHITOSAN AND SURFACTANT
Aflatoxins (AFs), a group of closely related, extremely toxic mycotoxins produced by some strains of the molds - Aspergillus flavus and Aspergillus parasiticus, can occur as natural contaminants of food and feeds worldwide. In the current study adsorption of aflatoxin B1 (the most toxic representative of AFs), was followed by bentonite – B (supplied from Getraco, d.o.o), B modified with commercial low molecular weight chitosan (sample B–Ch) as well as B–Ch modified with surfactant – hexadecyltrimethyl ammonium bromide (sample B–Ch–S). The initial raw material B and both composites were characterized by thermal analysis (TG/DTG) and determination of zeta potential. Results confirmed presence of chitosan in sample B–Ch and both chitosan and surfactant in sample B–Ch–S. Adsorption of aflatoxin B1 by B, B–Ch and B–Ch–S was investigated at different amounts of each adsorbent in suspension in buffer solution at pH 3 and 7, at fixed contact time (30 min). Results showed that for all materials, aflatoxin B1 adsorption increased with increasing the amount of each adsorbent in suspension and adsorption was practically independent of the solution pH. Although B already has high affinity to adsorb aflatoxin B1, the presence of chitosan and/or surfactant slightly increased adsorption of investigated mycotoxin at pH 3 and 7. Since both chitosan and surfactant have potential antibacterial activity, specifically composite B–Ch–S has a potential for a practical application as an animal feed additive.
AI-ENHANCED POLYMER-BASED NANOPLATFORMS FOR DRUG/GENE DELIVERY
Recent progress in gene therapy has ushered in a new era of medicinal treatments and established a foundation for next-generation technologies. The success of gene therapy is significantly dependent on an effective gene delivery system. In this regard, both natural and synthetic macromolecules play a crucial role in soft nanotechnology, enabling the creation of delivery vectors with customized compositions and functionalities. We present an innovative computational approach aimed at optimizing polymer and/or nanocomposite structures as efficient components for polymer-based nanoplatforms (PBNs). These PBNs are envisioned as vital frameworks for evolving from traditional drug and gene delivery techniques to personalized medicine. By merging state-of-the-art artificial intelligence with advanced modeling methods, we enhance the adaptive design of these polymer-based nanoplatforms in a synergistic way.
Biomaterials and Biomedical Applications
EXPERIMENTAL DESIGN OPTIMIZATION OF INTEGRATED ULTRASONIC- AND MICROWAVE-ASSISTED EXTRACTION OF RARE EARTH ELEMENTS FROM COAL ASH
The utilization of coal fly ash as a raw waste material from thermal power plants represents a promising alternative source for recovering rare earth elements (REEs). The significance of these elements lies in their broad application and uneven and limited global distribution. In this study, a method of extraction of REEs from coal ash was developed and optimized through alkaline pretreatment, followed by acid leaching. The optimization process was conducted using the Plackett-Burman and Box-Behnken designs. The identified optimal conditions involved a pretreatment procedure in an ultrasonic bath set at 95°C for 10 minutes with an ash-to-3M NaOH ratio of 0.5:1 (m/V). Acid leaching was a consecutive step in a microwave oven at 174°C for 30 minutes using an HCl/HNO₃ mixture in a 1:1 volumetric ratio. The method was tested on fly and bottom ash samples from the Kostolac thermal power plant in the Republic of Serbia, achieving 76% and 58% recovery efficiencies, respectively.
RECYCLING SILICON FROM SECONDARY SOURCES: WASTE SOLAR WAFERS AND DIAMOND WIRE SAW KERF SLURRY IN PHOTOVOLTAIC INDUSTRY
The surge in global interest in installing solar panels in recent years has been remarkable, in 2022, 250.000 MW of new capacity, primarily silicon (Si) based cell technology was installed (Chowdhury et al. 2020). Only in the past few years, there has been a substantial amount of solar panels, installed in the only 2000´s reaching end-of-life (EoL), with the big wave of EoL panels approaching. In 2050, there will be approximately 7 million tonnes of EoL panels. This implies the potential recovery of 7.000 to 70.000 tonnes of silver (Ag) and 210.000 to 350.000 tonnes of Si (Weckend et al. 2016). Without a comprehensive strategy for recycling them, we face the prospect of accumulating a mountain of EoL solar panels in the coming decades. Moreover, during the slicing of purified silicon ingots into wafers, the process of cutting multi-crystalline silicon ingots generates up to 40% Si kerf slurry waste. The rapid expansion of the global photovoltaic (PV) industry has resulted in a significant increase in diamond-wire saw kerf slurry waste. To reduce the costs of producing crystalline Si and mitigate environmental pollution caused by EoL solar panels and Si kerf slurry, recycling these materials has become imperative. In this work, the recycling of Si from waste solar wafers and Si kerf slurry in the solar industry are investigated using both pyrometallurgical and hydrometallurgical methods.
NOVEL MATERIALS IN PARTICLE PHYSICS EXPERIMENTS WITH HL-LHC AT CERN
The High-Luminosity Large Hadron Collider (HL-LHC) represents a major upgrade to the LHC increasing particle collision rates to 200 per bunch crossing, aiming to increase integrated luminosity by a factor of ten to expand the discovery potential of CERN’s experimental physics program that will last well into 2030s. Achieving the ambitious performance goals of the HL-LHC places unprecedented demands on the materials used in the accelerator infrastructure. To meet the demanding conditions of the HL-LHC—such as extreme radiation levels, higher data rates, and tighter spatial constraints—requires the development and integration of novel materials across particle detector systems that need upgrade. This talk will provide an overview of cutting-edge materials research supporting HL-LHC and detectors upgrades, including advanced superconductors for high-field magnets, radiation-hard silicon for tracking detectors, ultra-lightweight carbon composites for mechanical supports, and new scintillating and photonic materials. Emphasis will be given to the interdisciplinary efforts driving these innovations, as well as their implications on performance, longevity, and future applications in high-energy physics.
INVESTIGATION OF THERMAL AND ELECTRICAL PROPERTIES OF COPPER ALLOYS
This paper focuses on the investigation of thermal and electrical properties of copper alloys produced at Copper Mill Sevojno. The investigated copper alloys include high-purity copper (Cu-DHP) and a series of brass alloys with different zinc content (CuZn15, CuZn28, CuZn30, CuZn37). The samples were subjected to different thermomechanical treatments, including annealing at different temperatures and plastic deformation to different degrees, resulting in soft, semi-hard, or hard material states. Measurements of thermal diffusivity, specific heat capacity, and thermal conductivity were carried out in the temperature range from 25 to 400 °C using the light flash method (Discovery Xenon Flash, DXF-500). Differential scanning calorimetry (DSC) was applied to determine thermal characteristics, while electrical conductivity was measured using the “Institut Dr. Förster Sigmatest 2.063” device. The results showed significant differences between the samples, depending on their chemical composition and thermomechanical treatment. For instance, Cu-DHP demonstrated the highest thermal and electrical conductivity, while conductivity for a series of brass alloys decreased with increasing zinc content. The collected data provide a clearer picture of the behavior of these alloys, especially in terms of heat and electrical transport.
EPOXY/PVB HYBRID COMPOSITES REINFORCED WITH NANO-BORON CARBIDE: STRUCTURE, THERMAL STABILITY, AND MECHANICAL RESISTANCE
A novel epoxy/poly(vinyl butyral) (PVB) hybrid composite reinforced with nano-boron carbide (B₄C) particles has been developed to explore its potential for high-performance protective coatings and structural applications. Boron carbide, known for its exceptional hardness, wear resistance, and thermal stability, is incorporated into the polymer matrix to enhance mechanical durability, impact resistance, and erosion resistance. B₄C-based composites have also found application in electrochemical energy storage devices due to their chemical stability, electrical conductivity, and corrosion resistance. A comprehensive characterization of the composite includes scanning electron microscopy (SEM) to assess nano-B₄C dispersion and morphology, differential scanning calorimetry (DSC) to evaluate thermal stability and phase transitions, and Fourier-transform infrared spectroscopy (FTIR) to investigate chemical interactions within the polymer matrix. The mechanical performance is examined through hardness testing, Charpy impact testing, and ultrasonic cavitation resistance measurements, providing insight into the composite’s ability to withstand dynamic loading and erosive environments. The results demonstrate that nano-B₄C reinforcement significantly improves impact resistance, surface hardness, and cavitation durability, positioning these composites as promising multi-functional materials for potential use in abrasion-resistant coatings, ballistic protection, and aerospace applications, but also in electrochemical industry.
LETROZOLE DRUG DISSOLUTION FROM CLINOPTILOLITE ZEOLITE: EXPERIMENTAL AND THEORETICAL CONSIDERATIONS
Dissolution of water-insoluble drugs is an important challenge in drug delivery. Adsorbing water-insoluble drugs onto nanoporous carriers such as zeolites can improve drug dissolution. The drug molecules adsorbed in a thin layer onto nanoporous carriers are fully exposed to the solvent, enhancing the dissolution process. This presentation will give new insights into the adsorption of water-insoluble letrozole drug onto the nanoporous clinoptilolite zeolite from a nanoscale-science point of view based on experimental and theoretical considerations. Adsorption of the letrozole drug on clinoptilolite zeolite will be conducted from the colloidal dispersion state. The amount of letrozole adsorbed in a monolayer will be evidenced by thermogravimetric measurements, while optical spectroscopy techniques will reveal the interactions of the letrozole drug on the nanoporous zeolite framework. Positive adsorption energy at the letrozole-clinoptilolite interface calculated using density functional theory models suggests a small affinity for letrozole adsorption, suggesting the letrozole release is more favorable than the adsorption process. Thus, this presentation will show new possibilities in adsorption and dissolution of water-insoluble drugs.
SYMBIOSIS OF SURFACE HARDNESS OF STRUCTURE AND MATERIAL FATIGUE – PROJECTION OF REMAINING LIFETIME
The existence of plastic deformations on the surface part causes an increase in the hardness on the surface. The level of hardness is increased on the part of the structure that is subjected to higher loads, i.e. the existence of plastic deformations (cracks, fissures, fractures). Measuring hardness in this case is a diagnostic technique that can prevent the appearance of cracks on the structure. Hardness measurement can be used to determine the optimal service life of a steel structure in dynamically complex structures. Hardness measurement can also be linked to material fatigue – the longer the service life of a structure, with cyclic loads over time, the greater the plasticity of the material. The hardness automatically increases due to the increased number of cycles. The more the plasticity of the material increases, the greater the hardness, i.e. the greater the likelihood of cracks appearing in the structure. The upper rotary platform of the SRs2000+VR bucket wheel excavator was used for hardness testing. The platform has the shape of a cylinder with reinforcements and its function is to transfer all loads, both static and dynamic, from the upper rotary structure of the excavator to the lower structure of the excavator. The operational safety and service life (especially from a risk perspective) depend on the integrity of the structure of this part of the excavator structure. Under static and dynamic loading, the hardness value changes. All measured values ​​are greater than the nominal value, indicating an increase in the hardness or ductility of the structural steel (to a greater or lesser extent). The measured values ​​range from 6.3 HRc to 16.3 HRc. This hardness level corresponds to a tensile strength of 585 MPa to 705 MPa. Compared to the nominal, initial hardness for steel St52-3 of 575 MPa, large deviations are observed. The increased level of measured hardness indicates an increased level of plasticity of the parts of the turntable structure, which can also be characterized as material fatigue. Differences in hardness provide information about the degree of fatigue of the structure, i.e. for identifying parts of the structure where there is an increased level of probability of expected failures.
DETERMINATION OF LATENT HEAT FOR ALSI7CU1 ALLOY APPLYING DSC, TA, AND COMMERCIAL SOFTWARE PACKAGES
Latent heat of cast hypoeutectic aluminum alloys is commonly measured using Differential Scanning Calorimetry (DSC) or calculated using software packages (Thermo-Calc, JMatPro, FactSage) as well as applying cooling curve analysis (Thermal analysis technique). This study used the DSC method to comprehensively evaluate the accuracy of calculated latent heat for a specific AlSi7Cu1 alloy, considering its solidification under different cooling conditions. The alloy was analyzed under three distinct cooling/heating rates: 6, 10, and 50 °C/min. The commercial software packages (Thermo-Calc, JMatPro, and Fact Sage) and thermal analysis techniques (Newtonian, Fourier, and Energy balance methods) were used to calculate the investigated alloys' latent heat. The results obtained show good agreement between the measured and calculated values. Higher cooling rates, such as 50 °C/min, resulted in a reduced latent heat release compared to slower rates, such as 10 °C/min and 6 °C/min.
SYNTHESIS OF TIN SULFIDE USING HIGH EXOTHERMIC REACTION
Because of very important compounds such as tin sulfide, tin is critical metal for green economy. SnS applications are mostly used in optoelectronic devices (photovoltaics), lithium- and sodium-ion batteries, and sensors among others with a significant potential for a variety of future uses. Thermochemical analysis of synthesis of SnS and SnS2 was used for an analysis of possibility for formation of the aimed product. This study explores pyrometallurgical method for synthesis of SnS using pure elements of tin and Sulphur through one strong exothermic reaction in laboratory conditions. The goal is to offer new synthesis method in one closed reactor at temperatures between 220° and 440°C. The mass loss during synthesis was followed in the static conditions. We concluded that this synthesis of SnS can be controlled via an exothermic reaction in very short time. The better results can be reached using the synthesis process in dynamic conditions via an intensive mixing through the synthesis reaction
COMBUSTION OF CONTAMINATED SORGHUM SPP. FOR ZN EXTRACTION
Due to its properties, forage sorghum can grow under unfavorable soil conditions and in places with very harsh climatic conditions. Also, it is very tolerant of habitats that are contaminated with metals. Certain varieties of sorghum are capable of absorbing Zn from polluted soil. In this study, the optimal burning time and temperature of Sorghum spp. with the aim of obtaining ash with the highest possible concentration of Zn. Applying the chemical analysis of the homogenized initial sample of sorghum, it was established that 1 kg of sorghum contains 55.61 mg of Zn. Combustion experiments were performed at temperatures of 400, 450, 500 and 600 oC for 120, 240 and 360 minutes. In all experiments, the mass loss was approximately 90%. It was observed that the highest content of Zn has the ash that was formed after burning for 6 hours at a temperature of 500 oC. Differential thermogravimetric analysis showed that the greatest mass loss of the sample (ash) was recorded at a temperature between 150 and 400 oC. In order for the valorization of zinc from the ash to be possible, it is necessary that the ash and leachate (after washing the ash) do not contain any substance that would prevent the precipitation of zinc salts.
ADVANCEMENTS IN COMMINUTION EQUIPMENT FOR MINING: INNOVATIONS IN CRUSHING AND GRINDING TECHNOLOGIES
Comminution, which includes crushing and grinding, is one of the most energy-intensive processes in the mining industry, accounting for up to 50% of total energy consumption in mineral processing plants. Recent technological advancements have introduced more efficient, cost-effective, and environmentally friendly comminution equipment. This paper reviews the latest innovations in crushing and grinding technologies, including high-pressure grinding rolls (HPGR), vertical roller mills (VRM), and advanced cone crushers with real-time optimization systems. The study evaluates the energy efficiency, operational performance, and economic feasibility of these devices compared to traditional equipment such as ball mills and jaw crushers. The findings suggest that adopting modern comminution technologies can significantly reduce energy consumption, improve particle size distribution, and lower operational costs. These advancements contribute to more sustainable mining operations by minimizing environmental impact and optimizing resource utilization.
CHARACTERISATION OF THE 316L STEEL PRODUCED BY LASER WIRE ADDITIVE MANUFACTURING
This paper presents the results of testing the material obtained by additive manufacturing, using the laser wire additive manufacturing method, of steel quality 316L according to ASTM A240. Testing of the mechanical and microstructural properties of the material was carried out in two build directions, horizontal and vertical. In the horizontal direction mechanical properties were: Rm=609 МРа, A=41,0 %, Rp0.2=520 МРа, while in the vertical they were: Rm=623 МРа , A=36,8 %, Rp0.2=349 МРа. Based on obtained results, the largest deviation in the value was observed for Rp0.2, while the hardness was uniform for both build directions, about 200 HV. The residual stresses in the as-build state have a compressive character, which is consistent with the behavior of the material during hardening.
Coating is a surface modification technique frequently applied to agglomerates to improve performance, handling, appearance, and integrity. The process involves applying a thin layer of material to pellets or granules, offering benefits such as reduced dust formation, improved flowability, moisture resistance, and controlled solubility. This paper discusses the key advantages of coating, the selection of appropriate coating materials, and equipment used for application, with reference to industry practices and relevant literature.
EFFECT OF HEAT TREATMENT ON CORROSION RESISTANCE OF EN AW-7075 ALLOY
In this study, the effects of different heat treatment tempers on corrosion behavior of EN AW-7075 alloy were investigated. Corrosion behavior was determined for the alloy in artificial (T6 temper) and multi-stage aging (T77 temper, i.e. RRA). With the intention to predict corrosion behavior of the EN AW-7075 alloy in T6 and T77 temper, specimens were tested over chemical and electrochemical methods. Specimens were chemical investigated on exfoliation corrosion susceptibility (EXCO test) and intergranular corrosion resistance in accordance to ASTM G34 and ASTM G110 respectively. Applied electrochemical methods were included open circuit potential, electrochemical impedance spectroscopy and potentiodynamic polarization. Gained results shown that resistance to exfoliating corrosion is greater in the T6 compared to the T77 temper, with corrosion current density of 1.305 mAcm-2 for T6 temper compared to 1.348 mAcm-2 for T77 temper. On the other hand, EN AW-7075 alloy in the T77 temper has better intergranular corrosion resistance than in the T6 temper, with corrosion current density of 16.84 µA cm-2 for T77 temper compared to 97.27 µA cm-2 for T6 temper.
BASIC SUPERCAPACITIVE PROPERTIES OF GRAPHENE/CARBON NON-WOVEN FABRIC COMPOSITE
Flexible and lightweight supercapacitors are optimal power supplies for portable electronic devices. One of their key components is the flexible current collector, which should meet several requirements: high conductivity to minimize internal resistance while remaining light and improved mass specific capacitance. Carbon non-woven fabric (CNW) is a promising flexible current collector due to its exceptional flexibility, mechanical stability, light weight, ease of fabrication and cost efficiency. In this work, graphene, as widely recognized supercapacitive material, was deposited on CNW and the charge storage properties of the resulting composite were investigated. The electrochemical properties of neat CNW and the CNW/graphene composite were investigated in a 0.5 M Na2SO4 electrolyte in a standard three-electrode cell, using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). CV measurements were performed at sweep rates of 200, 100, 50, and 10 mV s⁻¹, while EIS was carried out at open circuit potential over a frequency range of 100 kHz to 10 mHz. The results obtained are characteristic of capacitive materials in which charge storage occurs through the electric double-layer capacitance mechanism. The enhanced capacitive response of the CNW/graphene composite, compared to neat CNW, is attributed to the high electrical conductivity and large specific surface area of graphene, which facilitate more efficient charge accumulation at the electrode/electrolyte interface. These findings demonstrate that CNW is a promising flexible current collector for graphene-based capacitive applications.
Materials for Energy Storage and Conversion
INFLUENCE OF OXIDANT CONCENTRATION ON THE LEACHING OF FLOTATION TAILINGS IN ACIDIC MEDIUM
The reprocessing of sulphide minerals in flotation tailings is an attractive option for sustainable mine waste management. Conventional mineral processing methods often encounter difficulties when processing tailings, mainly due to factors such as particle size and surface oxidation of minerals. In most cases, copper is extracted from such raw materials using leaching processes. The paper presents an investigation of the leaching of flotation tailings using 0.1 mol/dm3 H2SO4 solution in which ferric ions and hydrogen peroxide play the role of oxidants. The influence of oxidant concentration on the leaching of copper and iron was investigated. It was found that the addition of ferric ions influenced the leaching of copper, with approximately 79% of copper was leached with 5 g/dm3 of Fe(III) ions. It has also been shown that the concentration of hydrogen peroxide affects the leaching of copper and iron. The total copper extraction of 85.31% and iron extraction of 7.66% were achieved with 0.3 mol/dm3 H2O2 during 120 minutes of reaction time.
ENGINEERING TITANIUM-BASED MATERIALS: HIGH-PRESSURE TORSION AND SURFACE NANOSTRUCTURING
The coarse-grained (CG) and ultrafine-grained (UFG) Ti-13Nb-13Zr alloys were used as tested materials in this study. The UFG alloy was obtained using a high-pressure torsion process (HPT) under a pressure of 4.1 GPa with a rotational speed of 0.2 rpm up to 5 rotations at room temperature. The structure of titanium alloy may be modified by high-pressure torsion (HPT) which is one of the most popular severe plastic deformation (SPD) methods. HPT process leads to the forming of submicron-sized grains in structure. Also, the HPT process leads to improving the mechanical and corrosion properties of titanium alloy. In order to analyze the influence of the HPT process on the morphology and characteristics of the nanostructured surface, Ti-13Nb-13Zr alloy was modified by anodic oxidation. Anodic oxidation in the 1M H3PO4 + NaF electrolyte was used as a method for the nanostructured surface of titanium-based materials. Scanning electron microscopy (SEM) was used to characterize the morphology of the surface, while surface roughness was determined using atomic force microscopy (AFM). The surface mechanical properties before and after the anodic oxidation were examined using the nanoindentation test. Corrosion resistance was tested in artificial saliva with a pH value of 5.5 at 37°C, to simulate the environment in the human body. The impact of the HPT process on the morphology of the nanostructured surface (homogeneity of the modified surface, diameter, wall thickness, and length of nanotubes) has been shown. It has been shown that anodic oxidation increases the roughness of the surface, while this increase is more pronounced after the HPT process. Characterization of the CG and UFG TNZ alloy surface after anodic oxidation showed a decrease in the values of surface mechanical properties, whereby they approached the values of the mechanical properties of human bone tissue. Also, results showed that corrosion resistance was increased after anodic oxidation, for both materials.
SURFACTANT-MODIFIED KAOLIN - ADSORBENT FOR OCHRATOXIN A AND KETOPROFEN
This study investigates the potential of surfactant-modified kaolin as an adsorbent for two different purposes: the decontamination of animal feed and the removal of pharmaceuticals from water. The model substances selected for this research were ochratoxin A (OCHRA), a mycotoxin commonly found in animal feed, and ketoprofen (KET), a nonsteroidal anti-inflammatory drug (NSAID) often detected in water sources. The natural kaolin was modified with quaternary ammonium salt (hexadecyltrimethylammonium – HDTMA bromide) in an amount equal to 50% of kaolin's cation exchange capacity (CEC). The successful modification was confirmed by two characterization methods - Fourier Transformed Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). Adsorption experiments were performed at different initial concentrations of investigated pollutants at pH 7. The results of this study reveal that the modification of kaolin with organic cations significantly enhances its ability to adsorb both OCHRA and KET, with adsorption efficiency increasing as the concentration of investigated analytes rise. This research demonstrates that surfactant-modified kaolin exhibits high adsorption capacity for both contaminants, with significant improvement in removal efficiency compared to unmodified kaolin, highlighting its potential as an effective adsorbent for environmental and health risks associated with these substances.