Technical Faculty in Bor
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Recent Submissions
Potential of using zinc processing tailings (ZPT’s) in the production of burnt clay bricks
(University of Belgrade, Technical faculty in Bor, 2025) Messai, Ali; Berrekbia Linda; Meramria, Ikram; Menendez-Aguado, Juan Maria; Fernandez-Perez, Begona; Nikolić, Vladimir; Trumić, Milan; Boustila, Amir
Zinc processing tailings (ZPTs) from the Kharzet Youcef processing complex (Setif- Algeria) are mainly stockpiled in tailings dumps without use, occupying a significant area with potentially influencing the environment and human health. Incorporating ZPTs in building materials manufacturing is an effective solution to meet the dual objectives of environmental protection and economic development. The study investigates the influence of integrating ZPTs to partially replace clays and firing temperature on the physic-mechanical properties of fired clay bricks (FCB). Microstructural, chemical, and mineralogical analyses of ZPT and clays were carried out by SEM-EDS, XRF and XRD, respectively. Seven mixtures were produced with various percentages of ZPTs added to clays (0%, 5%, 10%, 15%, 20%, 25% and 30%) and were fired to three different temperatures (950, 1000 and 1050 °C) at a ramp rate of 5 °C. Physic-mechanical tests were carried out on different brick specimens, and the results obtained showed the FCB incorporated with 30% of ZPTs produced the highest flexural strength of 6.24 MPa, compressive resistance of 29.78 MPa, bulk density of 1.37 g/cm3 and water absorption of 15.1% at 900 °C. Therefore, recycling ZPTs for FCB manufacturing is a feasible alternative waste disposal solution for sustainable development while reducing negative environmental impacts.
Proposal of a Method for Calculating the Bond Work Index for Samples with Non-Standard Feed Particle Size Distribution
(MDPI, Switzerland, 2025) Nikolić, Vladimir; Medina Pierres, Jesús; Sanchez Calvo, Maria; Menendez-Aguado, Juan Maria; Trumić, Milan; Trumić, Maja; Milošević, Vladan
Determining the Bond grindability test in a ball mill is one of the most commonly used methods in the mining industry for measuring the hardness of ores. The test is an essential part of the Bond work index methodology for designing and calculating the efficiency of mineral grinding circuits. The Bond ball mill grindability test has several restrictions, including the sample’s initial particle size distribution (PSD). This paper presents a method for calculating the Bond work index when the Bond ball mill grindability test is performed on samples with non-standard PSD. The presented equation includes a correction factor (k) and is applicable only for P100 = 75 μm. The defined method is then compared with methods proposed by other researchers, and conclusions are drawn as to which method results in less deviation. The presented model resulted in a mean square error of 0.66%.
Utilisation of Zinc Processing Tailings (ZPTs) in Fired Clay Bricks Manufacturing: Case Study
(MDPI, Switzerland, 2025) Messai, Ali; Menendez-Aguado, Juan Maria; Berrekbia, Linda; Meramria, Ikram; Fernandez-Perez, Begona; Nikolić, Vladimir; Trumić, Milan; Boustila, Amir
Zinc processing tailings (ZPTs) of the Kharzet Youcef processing complex, Setif, Algeria, are mainly stockpiled in tailing dumps without use, occupying significant surfaces and negatively influencing the human environment and health. Incorporating ZPTs into building materials manufacturing is an effective solution to meet the dual objectives of environmental protection and economic development. This study investigates the influence of firing temperature and integrating ZPTs as a partial replacement for clay on the physic-mechanical properties of fired clay bricks (FCBs). Microstructural, chemical, and mineralogical analyses of ZPTs and clay were carried out by SEM-EDS, XRF, and XRD, respectively. Seven mixtures were produced with various percentages of ZPTs added to clay (0%, 5%, 10%, 15%, 20%, 25%, and 30%) and were fired at two different temperatures (900 and 1000 °C) at a ramp rate of 5 °C. Physic-mechanical tests were carried out on different brick specimens, and the results obtained showed that the FCBs incorporated with 10% of ZPTs produced the highest flexural strength of 6.24 MPa, compressive resistance of 29.78 MPa, bulk density of 1.37 g/cm3, and water absorption of 15.1% at 900 °C. Therefore, the recycling of ZPTs for FCBs manufacturing is feasible and an effective alternative waste disposal solution for sustainable development while reducing negative environmental impacts.
Influence of pre-deformation on mechanical properties and microstructure of EN-AW 7075 aluminium alloy
(Materials Research Society of Serbia, 2025) Kovačević, Avram; Stamenković, Uroš; Nedeljković, Milan
This study investigates the changes in mechanical properties and microstructure of the EN-AW 7075 aluminum alloy after thermomechanical treatment. The treatment included cold plastic deformation, induced by rolling prior to artificial aging at a temperature of 150 °C for 30 minutes. The variations in hardness and impact toughness were monitored depending on the applied thermomechanical treatment conditions. Hardness was determined using the Leeb method, while impact toughness was measured using the Charpy method. The lowest hardness values were recorded in the annealed condition (Temper O state), while the highest impact toughness was observed in the quenched condition (Temper W state). The applied cold plastic deformation induced before artificial aging significantly increased the hardness of the investigated alloy, accompanied by a progressive decrease in impact toughness. Optical microscopy was used to analyze the microstructural changes during the thermomechanical treatment. Precipitates of various sizes and morphologies were observed in the alloy structure. The annealed condition was characterized by poorly defined grain boundaries and coarse secondary phase particles uniformly distributed within the matrix. Cold plastic deformation before aging resulted in a structure oriented in the rolling direction and refined secondary phase particles.
Thermal Properties and Microstructure Evolution of the as‑cast and Annealed Al–Cu–Si Eutectic Alloy
(Springer Nature, 2025) Manasijević, Dragan; Marković, Ivana; Cimpoesu, Nicanor; Chelariu, Romeu; Stamenković, Uroš; Balanović, Ljubiša; Gorgievski, Milan
The Al–28%Cu–6%Si (mass%) eutectic alloy represents a possible high-temperature phase change material (PCM) for latent heat thermal energy storage (LHTES). In this paper, its microstructural characteristics and thermal properties were examined in the as-cast and annealed conditions using scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), differential scanning calorimetry (DSC), and light flash method. The microstructure of the studied alloy consists of (Al) solid solution phase, θ-Al2Cu intermetallic phase, and (Si) phase. The annealing at 450°C for 50 h led to significant changes in the morphology of the θ-Al2Cu and (Si) eutectic phases. The temperature dependences of thermal diffusivity and thermal conductivity were investigated within the temperature range from 25 to 400 °C. It was found that the thermal diffusivity and thermal conductivity of the annealed alloy are considerably higher than that of the as-cast alloy at temperatures lower than 300 °C. With increasing temperature, due to changes in the microstructure of the as-cast alloy, these differences decrease and finally diminish at 400 °C. The measured eutectic temperature is 522.3 °C and latent heat of melting is 358.3 Jg-1. The findings suggest that the Al–Cu–Si eutectic alloy shows good potential for use in phase change energy storage technologies.