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New Constraints on the Main Mineralization Event Inferred from the Latest Discoveries in the Bor Metallogenetic Zone (BMZ, East Serbia)
(MDPI, 2019) Banješević, Miodrag; Cvetković, Vladica; von Quadt, Albrecht; Ljubović Obradović, Darivojka; Vasić, Nebojša; Pačevski, Aleksandar; Peytcheva, Irena
This study aims at better constraining the link between magmatism and metallogeny in the south-easternmost sector of the Bor Metallogenetic Zone (BMZ), where the world-class copper and gold deposit of Čukaru Peki was recently discovered. The obtained U/Pb zircon ages confirm the earlier knowledge that the major Cu–Au porphyry and epithermal mineralization in the BMZ is genetically related to the first volcanic phase (‘Timok andesite’; 85–90 Ma). However, the data also suggest that during this phase, two subgroups of andesite porphyry were formed; they are named volcanic phase 1A (V1A) and volcanic phase 1B (V1B). The V1A andesite (89–90 Ma) is plagioclase-hornblende phyric, holocrystalline and ubiquitously hydrothermally altered and/or mineralized, whereas the V1B (85–86 Ma) is hornblende-plagioclase phyric, holo- to hypocrystalline, fresh, and non-mineralized. According to our simplified model, the contrasting productivity of the V1A and V1B is explained by fluctuations during AFC (assimilation-fractional crystallization) processes of water-rich parental magma, which have controlled the order of crystallization of hornblende and plagioclase in the V1A and V1B andesite.
An investigation into foreign language anxiety (FLA) among students at the Technical Faculty in Bor
(University of Belgrade, Faculty of Philology, 2020) Stevanović, Slavica; Vasković, Sandra
Despite the fact that foreign language anxiety (FLA) has attracted much interest over the last thirty years and that FLA has also been recognized and documented as one of the factors affecting learner performance, this aspect of EFL has been disregarded in Serbia, and there are no studies that we are aware of concerning this phenomenon. This paper is aimed at presenting findings on FLA of 101 first-year students of the Technical Faculty in Bor, Serbia, and contributing to the existing literature on FLA, as well as at confirming the reliability of Foreign Language Anxiety Scale (FCLAS) as an instrument to measure potential anxiety in EFL classroom. The theoretical objective of this study was to examine Horwitz et al.’s model of FCLAS as well as to produce an adapted version of FCLAS suitable for Serbian learners’ attitude towards FLA. The adapted version of FCLAS was administered to 101 non-major English students of the Technical Faculty in Bor, and the findings are presented in this paper.
Proceedings - 52nd International October Conference on Mining and Metallurgy - IOC 2021, November 29th - 30th 2021, Bor, Serbia
(University of Belgrade, Technical Faculty in Bor, 2021) Stojadinović, Saša; Petrović, Dejan
Study of microstructure and thermal conductivity of the Ag–Bi–Sn alloys
(University of Belgrade, Technical Faculty in Bor, 2021) Manasijević, Dragan; Balanović, Ljubiša; Marković, Ivana; Gorgievski, Milan; Stamenković, Uroš; Božinović, Kristina; Minić, Duško; Premović, Milena
Five Ag–Bi–Sn ternary alloys with changeable tin concentration ranging from 12.8 to 75.1 mass% and nearly equal mass contents of silver and bismuth were investigated in this study. Microstructures of as-solidified alloy samples were examined using scanning electron microscopy with energy dispersive X-ray spectrometry (SEM-EDS) The observed microconstituents were Ag3Sn and (Bi) phases as well as ternary (Sn)+(Bi)+Ag3Sn eutectic. The flash method was used for thermal diffusivity measurements in the temperature range from 25 to 100 °C. Based on the measured values of thermal diffusivity, thermal conductivity of the solid Ag–Bi–Sn alloys was obtained. Thermal conductivity of the studied Ag–Bi–Sn ternary alloys considerably increases with increasing tin concentration and slightly decreases with increasing temperature.
Impact of extraordinary security measures to employees during the pandemic Covid-19
(University of Belgrade, Technical Faculty in Bor, 2021) Miletić, Slavica; Bogdanović, Dejan; Požega, Emina
Today's modern business organizations in times of pandemic caused COVIDE -19 are not in a situation to take place without the required extraordinary security measures. The implementation of extraordinary security measures is becoming increasingly important, especially in today's current wisdom changing market during the pandemic.The aim of this paper is to assess the progress of the impact of extraordinary security measures on employees during the COVID-19 pandemic.The evaluation of indicat rs / criteria was done by AHP method.Suppression progressthe COVID-19 pandemic demonstrates the effectiveness of the proposed approach.
Part I: What makes a good thermoelectric
(University of Belgrade, Technical Faculty in Bor, 2021) Požega, Emina; Simonović, Danijela; Marjanović, Saša; Jovanović, Milenko; Gomidželović, Lidija; Mitrović, Milijana; Stanojević Šimšić, Zdenka
Starting from spectroscopy pure materials, a monocrystal sample of p type, Bi2Te2.8Se0.2, was synthesized by the Bridgman method at the Serbian Academy of Sciences and Arts in Belgrade (SANU). The transport properties of single crystals were investigated. Transport properties have shown that with current increasing, mobility and Hall coefficient increase. Positive values of the Hall coefficient confirm that the material is of the p type with a high concentration of charge carriers,nb= 10 18 cm-3.
Part II: What makes a good thermoelectric
(University of Belgrade, Technical Faculty in Bor, 2021) Požega, Emina; Simonović, Danijela; Marjanović, Saša; Jovanović, Milenko; Gomidželović, Lidija; Mitrović, Milijana; Miletić, Slavica
Successful synthesis of p type single crystal Bi2Te2.8Se0.2 by the Bridgman process obtained at the Serbian Academy of Sciences and Arts (SANU) in Belgrade was performed. A significant scientific contribution has been made in the application field of bismuth telluride as a thermoelectric material and selenium as its dopant. In this way, the conducted research enriched the set of data relevant for further research.
Stratigraphy and age of rock units and mineralization in the Timok Magmatic Complex and the Bor Metallogenic Zone – a review
(University of Belgrade, Technical Faculty in Bor, 2021) Banješević, Miodrag
This study reports of stratigraphy and geochronology of rock units and mineralization of the Timok Magmatic Complex (TMC) and the Bor Metallogenetic Zone (BMZ)which belongs to theLate Cretaceous Apuseni-Banat-Timok-Srednogorje Belt (ABTS, part of the Tethyan-Eurasian Metallogenic Belt). Existing data are supplemented and systematized by the latest geological, stratigraphic and mineral exploration. The TMC developed on a continental crust composed of different types of the Proterozoic to the Lower Cretaceous rocks. The TMC consists of the volcanic/magmatic, volcanogeno-sedimentary and sedimentary units.The sedimentary processes and magmatism lasted nearly continuously throughout nearly the whole Late Cretaceous. The sedimentation lasted from the Albian-Cenomanian to the Maastrichtian. Magmatism occurred in two phases from the Upper Turonian to the Upper Campanian: V1 (90-83 Ma), V2 (83-78 Ma), with a steady decrease in age from east to west. Cu-Au porphyry mineralization take place between 87-80 Ma. Major mineralizationis related to the V1 magmatic phasepredominantly developed in the easternmost part of the BMZ.
Electrochemical behavior of copper in chloride medium in the presence of walnut shell macerate
(University of Belgrade, Technical Faculty in Bor, 2021) Grekulović, Vesna; Mitovski, Aleksandra; Rajčić Vujasinović, Mirjana; Štrbac, Nada; Zdravković, Milica; Gorgievski, Milan; Marković, Miljan
The use of plant extracts to inhibit the corrosion of copper and its alloys has been the subject of numerous scientific studies. This paper presents the results of research the electrochemical behavior of copper during oxidation in a solution of 0.5 mol/dm3NaCl in the absence and presence of walnut shell macerate in different concentrations. The electrochemical behavior of copper was investigated by method of open circuit potential measurement and cyclic voltammetry method. The results of measuring the open circuit potential show that the values obtained in the presence of walnut shell macerate are more positive in relation to the value recorded without the addition of walnut shell macerate. Three current peaks that correspond to copper chloride and copper oxide formation appear on the anode polarization curve obtained without the presence of walnut shell macerate. The value of current peaks decreases with increasing concentration of walnut shell macerate in the electrolyte. Lower current values in the presence of walnut shell macerate indicate that walnut shell macerate has got an inhibitory effect on processes resulting with these current peaks.
Dualphased fourway intersection regulated by traffic lights with fixed and adaptive mod of operation
(University of Belgrade, Technical Faculty in Bor, 2021) Radivojević, Milan; Stević, Zoran; Tanasković, Marko
Road traffic in many populated areas is mainly regulated using a traffic light, which in many cases is not sufficiently effectively configured. This can lead to unnecessary long waiting times and increase total time losses when passing through the intersection. This paper presents the results of the application program of the adaptive semaphore system of the four-way two phase intersection, made using the LabVIEW software package, as well as the data and results of the analysis of the functioning of the intersection with adaptive and fixed traffic mode.
pH and conductivity change during the rinsing and adsorption of copper ions onto walnut shells
(University of Belgrade, Technical Faculty in Bor, 2021) Marković, Miljan; Gorgievski, Milan; Štrbac, Nada; Grekulović, Vesna; Mitovski, Aleksandra; Božinović, Kristina; Zdravković, Milica
The change in pH and conductivity values during the rinsing of the walnut shells as well as during the adsorption of copper ions wasinvestigated in this study. The pH value increases during the rinsing of the adsorbent, reaching a constant value after the passing of 100 ml of distilled water. The increase in the pH value during the rinsing of the adsorbent occurs as a result of the transfer of H+ ions from the aqueous phase into the molecular structure of the adsorbent, where they are exchanged with alkali and alkaline- earth metal ions. As for conductivity change, a sudden increase in conductivity occurs after passing the first 50 ml of distilled water, followed by a decrease in conductivity with further rinsing. The increase in conductivity is most likely caused by the increase in the concentration of alkali and alkaline earth metal ions in the solution, which are being transferred from the adsorbent structure into the aqueous phase. During the adsorption process, the pH value rapidly increases for the first few minutes, after which starts to decline. The release of H+ ions from the adsorbent structure into the aqueous phase causes a rapid decrease in pH value as a result of the deprotonation of functional groups in the adsorbent molecular structure. The conductivity increases during the adsorption process. This increase is due to an increase in the concentration of alkali and alkaline earth metal ions in the solution, which are exchanged with copper ions during the adsorption process.
Adsorption isotherms for copper ions adsorption onto walnut shells
(University of Belgrade, Technical Faculty in Bor, 2021) Gorgievski, Milan; Marković, Miljan; Božić, Dragana; Stanković, Velizar; Štrbac, Nada; Grekulović, Vesna; Zdravković, Milica
In this paper Langmuir, Freundlich, and Temkin adsorption isotherm models were used for describing the adsorption of copper ions onto walnut shells. The adsorption was performed in a batch system. The obtained isotherm data were fitted using the mentioned models, and the isotherm parameters were calculated from the linearized plots corresponding to each model. The Langmuir adsorption isotherm model showed the best agreement with the analyzed experimental data, with the correlation coefficient R2 = 0.993. According to this model, the adsorption process occurs until a complete monolayer of copper ions is formed on the surface of the walnut shells. The maximum adsorption capacity, according to this model, was 7.71 mg g-1.
Experimental and thermodynamic study of isothermal sections at 600 °C and 400 °C of ternary Bi-Cu-Ge system
(University of Belgrade, Technical Faculty in Bor, 2021) Milosavljević, Milan; Premović, Milena; Minić, Duško; Manasijević, Dragan; Đorđević, Aleksandar; Kolarević, Milan
Experimental and computation thermodynamic is very important for future development of materials and knowledge of phase diagram. Knowledge of phase diagram without experimental confirmation is not worth a lot. In this study both calculation and experiments were performed for better knowledge of isothermal sections. Calculated phase diagrams were two isothermal sections at 600 °C and 400 °C. Calculations were done by using PANDAT software and thermodynamic data from literadute. Experimental were performed on 12 annealed alloys. Six alloys were prepared per isothermal section. Compositions od alloys and phases presented in microstructures were tested with SEM-EDS while determination of phases in samples were checked with XRD. Results of EDS were compared with calculated isothermal sections and good agreement were reached.
Hydrometallurgical treatment of electiric arc furnace dust in aim of zinc separation
(University of Belgrade, Technical Faculty in Bor , 2021) Trifunović, Vanja; Avramović, Ljiljana; Jonović, Radojka; Milić, Snežana; Đorđievski, Stefan; Jonović, Marko
During the steel production from secondary raw materials in the electric arc furnace, generation of the main intermediate of the process- dust from the electric arc furnace (EAF dust) occurs. This dust contains significant amounts of Zn and Fe, as well as Pb, Ca, Mn, Ni, Cu, Cd, Mg, Si, Cr, F, Cl and other elements and is considered hazardous industrial solid waste since it contains heavy metals. In order to separate Zn as a valuable component, hydrometallurgical treatment of EAF dust was investigated.The treatment consists of two stages: 1st stageis water leaching of EAF dust performed in order to remove water-soluble compounds, and 2nd stage is acid leaching in order to leach ZnO from EAF dust and obtain a ZnSO4solution. With optimal parameters of the water leaching process of EAF dust, the achieved leachingrates of water-soluble compounds are as follows: 80.84% Cl, 60.63% K, 52.95% Na, 18.23% Ca, while with acid leaching of the solid residue obtained after water leaching at optimal parameters achieved leaching rate of Zn is 82.34%. In addition to the economic aspect of this treatment where the separation of Zn from EAF dust is performed, the treatment also has an ecological aspect because the transformation of hazardous waste into non-hazardous waste is performed, which has a positive effect on the environment.
The influence of calcium ions on deinking flotation recovery under diferent conditions
(University of Belgrade, Technical Faculty in Bor, 2021) Marilović, Dragana; Trumić, Maja; Trumić, Milan; Andrić, Ljubiša
Deinking flotation is the most commonly used method in recycling paper process. Better understood of the interactions between added surfactant and the solid surfaces of ink can be accomplished by studying the fundamental mechanism. The effect of reagents on the flotation of offset paper was investigated for the purpose of efficiency removing the toner particles and fiber purification under different pH values in the presence of calcium ions. The results showed that calcium ions in combination with oleic acid remove toner particles with high efficiency in a short flotation time.
Chemical composition of particulate matter in the indoor air at the Technical faculty in Bor (Serbia)
(University of Belgrade, Technical Faculty in Bor, 2021) Tasić, Viša; Cocić, Mira; Radović, Bojan; Apostolovski-Trujić, Tatjana
This paper presents part of the research results of human's exposure to air pollution with suspended particles in selected educational and residential buildings in the town of Bor. In recent years, special attention has been paid to indoor air quality, because people spend a large part of their time during the day in closed micro-environments. Mass concentrations of 24 chemical elements were determined from PM10 samples collected in the selected classroom at the Technical Faculty in Bor during March 2018. Major elements (Fe, Al, Na, Mg, Ca, K) and trace elements (As, Cd, Pb, Ni, Zn, Cu, Ti, Co, V, among others) were analyzed by Inductively Coupled Plasma Optical Emission Spectrometry (ICP OES) and Inductively Coupled Plasma Mass Spectrometry (ICP MS), respectively. The phase composition of the total suspended particulate matter (TSPM) samples was determined by X-ray powder diffraction (XRPD) analysis. XRPD analysis of the SPM samples identified: calcite (CaCO3), quartz (SiO2), gypsum (CaSO4x2H2O), dolomite (CaMg(CO3)2) and plagioclase (albite – NaAlSi3O8).
Comparative results of copper flotation from slag before and after the process of magnetic concentration
(University of Belgrade, Technical Faculty in Bor, 2021) Ilić, Ivana; Sokolović, Jovica; Trumić, Maja; Štirbanović, Zoran
Previous research on the possibility of valorization of useful components from smelter slag has shown that copper and precious metals can be economically justifiably valorized by flotation concentration. In addition to the basic useful components, smelter slag also contains other useful components (iron) whose valorization would improve the economic effects of processing this secondary raw material. This paper presents the results of testing the possibility of valorization of copper and iron from the new smelter slag of Mining and Smelting Combine Bor (RTB) Bor using magnetic and flotation concentration.
Optimization of cathodic material leaching process in acid-sulphate solution
(University of Belgrade, Technical Faculty in Bor, 2021) Medić, Dragana; Milić, Snežana; Alagić, Slađana; Nujkić, Maja; Đorđievski, Stefan; Papludis, Aleksandra
Lithium cobalt oxide is the first commercialized electrode material with the greatest potential for recycling. In this paper, the influence of different process parameters (leaching agent concentrations, solid phase concentrations and temperatures) on the degree of cobalt leaching was investigated. It was found that the maximum degree of cobalt leaching (about 100%) is achieved at the following process parameters: sulfuric acid concentration was 3 mol/dm3, solid phase concentration was 33 g/dm3, volume flow of sulfur dioxide was 2 dm3/min, temperature was 85°C and leaching process duration was 60 minutes.
Study of temperature phase transformation of theternary Bi-Cu-Ge system
(University of Belgrade, Technical Faculty in Bor, 2021) Đorđević, Aleksandar; Minić, Duško; Premović, Milena; Mansijević, Dragan; Milosavljević, Milan; Ristić, Vladica
Decades of scientific work dedicated to the investigation of phase diagrams gave significant benefit to industry and science. After all those years of phase diagram investigation still there is missing information about phase diagram of some ternary systems. One of those systems is Bi-Cu-Ge. It is known importance of Cu-based alloys and Ge-based alloys in electro industry. Since such combination is not tested before this work will provide information about phase diagram of the three vertical sections from ternary Bi-Cu-Ge system. From each vertical sections (Bi-CuGe, Cu-BiGe and Ge-BiCu), 4 alloys were prepared and tested by DTA. Experimentally obtained results were compared with corresponding vertical sections. Experimental temperatures of phase transformation shows close value with calculated one. Temperatures of liquidus curve and primary crystallization were determined.
Obtaining multilayer copper strips by ARB (Accumulative Roll Bonding) rolling process
(University of Belgrade, Technical Faculty in Bor, 2021) Mitrović, Milijana; Gusković, Dragoslav; Marjanović, Saša; Trumić, Biserka; Požega, Emina; Stamenković, Uroš; Petrović, Jasmina
In this paper, the production of multilayer samples, by joining copper strips, by the rolling process at temperatures below the recrystallization temperature is presented. The newly obtained multilayer samples were then subjected to tensile testing and hardness measurement in order to determine their properties. The obtained results show that with increasing degree of reduction, the tensile strength and hardness of the samples increase. Up to the degree of reduction of 66.5%, the tensile strength and hardness of the samples increase slightly, while at a higher degree of reduction of 66.5%, the growth is much more pronounced.

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