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Alkali Fusion–Leaching Process for Non-Standard Copper Anode Slime (CAS)
No full textCopper anode slime (CAS), obtained from non-standard anodes by pyro-hydrometallurgical
electronic waste (e-waste) processing, contains high concentrations of lead, tin (as metastannic
acid), and base (Cu, Fe, Zn), precious (Au, Ag), and technological metals (In, Ga, Ge),
which limit the efficiency of conventional valorization methods. In this study, an integrated
alkali fusion–leaching process was applied to non-standard CAS. Thermodynamic modeling
defined the key parameters for selective phase transformations and efficient metal
separation. These parameters were experimentally investigated, and the optimized fusion
conditions (CAS:NaOH = 40:60, 600 ◦C, 60 min), followed by water leaching (200 g/dm3,
80 ◦C, 60 min, 250 rpm), resulted in >97% Sn removal efficiency. Simultaneously, Au and
Ag losses were negligible, resulting in solid residue enrichment. Oxidant addition (NaNO3)
did not improve Sn removal but increased Fe, Pb, and Ag solubility, reducing selectivity.
The scaled-up test confirmed process reproducibility, achieving 97.75% Sn dissolution and
retention of precious metals in the PbO-based residue (99.99% Au, 99.78% Ag). Application
of an integrated thermodynamic modeling, laboratory optimization, and scaled-up
validation approach to non-standard CAS provides a relevant framework for a selective,
efficient, and scalable method addressing industrial needs driven by increased e-waste
co-processing, contributing to sustainable metal recovery
Preliminary Study of Geochemical, Mineralogical and Magnetic Susceptibility Properties of Flotation Tailings from the Pb-Zn-Cu-Ag Rudnik Mine, Serbia
No full textSamples of flotation tailings generated during the exploitation and processing of Zn–Pb–Cu–Ag ore from the Rudnik mine (Serbia) were investigated for their mineralogical, geochemical, and magnetic susceptibility properties. The flotation tailings consist of a complex mineral assemblage, including silicates, carbonates, sulfides, phosphates, sulfates, oxides, hydroxides, and native elements. Quartz, calcite, and orthoclase dominate the coarse fraction (>400 µm), accompanied by epidote, Ca-garnet, and Ca-clinopyroxene. Sulfide minerals are concentrated in finer fractions (<400 µm), with pyrite and arsenopyrite being the most abundant, followed by pyrrhotite, sphalerite, galena, and chalcopyrite. These sulfides occur as dispersed grains within a silicate–carbonate matrix. Post-depositional oxidative alteration is moderately developed, with pyrite replaced by hematite, galena by cerussite, and chalcopyrite by malachite. Geochemical analyses reveal that SiO2 (avg. 38.98 wt%), Fe2O3 (avg. 23.68 wt%), Al2O3 (avg. 8.95 wt%), CaO (avg. 9.03 wt%) and MgO (avg. 1.50 wt%) dominate the composition. Economically significant metals include Zn (avg. 0.47 wt%), Pb (avg. 0.20 wt%), Cu (avg. 0.11 wt%), Ag (max. 19 µg/g), and Bi (max. 130 µg/g). Mass magnetic susceptibility shows a strong correlation with S (r = 0.92), Co (r = 0.90), and Bi (r = 0.87); moderate correlation with Fe2O3, Al2O3, and As; and negative correlation with Mn, TiO2, Zn, and Pb. The ferromagnetic phase most likely originates from pyrrhotite, as well as hematite formed during pyrite alteration and goethite
Atomistic modeling and experimental analysis of high-temperature deformation in Co-free non-equiatomic CrMnFe–Ni alloy
No full textThis invited seminar presents an atomistic modeling and experimental analysis of high-temperature deformation mechanisms in Co-free non-equiatomic CrMnFe–Ni alloys. Molecular dynamics simulations were combined with experimental characterization to investigate deformation behavior, phase stability, and defect evolution at elevated temperatures. The lecture was delivered as part of the NOMATEN Seminar Series and aimed to strengthen collaboration between computational and experimental materials research
Corrosion Resistance of Fluorapatite Nanoparticles: A Brief Review with a Focus on Biomedical Applications
No full textFluorapatite (FAP), a calcium phosphate compound, has gained significant attention as a promising material for various biomedical applications due to its excellent biocompatibility, osteoconductivity, and resistance to corrosion. The incorporation of fluoride ions into the crystal lattice of FAP enhances its structural stability, making it less susceptible to degradation in biological environments. FAP nanoparticles exhibit increased surface activity, improved adhesion, and a pronounced barrier effect compared to microparticles, which makes them highly suitable for use in protecting metal implants from corrosion. This review provides an overview of corrosion resistance of FAP
nanoparticles, focusing on the mechanisms that contribute to this property and its implications for biomedical applications. Key aspects such as FAP synthesis methods, bioactivity, and its role in bone regeneration, dental materials, and implant coatings are explored. Additionally, the mechanisms of corrosion protection offered by FAP, including surface passivation and the role of fluoride ions, are discussed in detail. Finally, the biomedical significance of these properties is evaluated, with an emphasis on their potential to improve the longevity and performance of implantable biomaterials
Characterization of an ore sample from Congo based on tantalum and niobium for possible further technological tests
No full textIn this study, two samples of ""Ta-Nb"" ore from Congo (MMR-1 and MMR-2) were analyzed. Various
physical and chemical properties were determined for these samples, including gross and hygroscopic
moisture, specific gravity, granulometric composition of the initial samples and after each level of crushing,
bulk density of the initial samples and after each crushing stage, and chemical composition. Qualitative
mineralogical analysis was conducted using X-ray diffraction (XRD), while polished sections were prepared for
optical microscopy, scanning electron microscopy (SEM), and mineralogical analysis by particle size classes.
Detailed physicochemical and mineralogical tests were carried out on the MMR-1 and MMR-2 samples to
comprehensively define the parameters necessary as a foundation for further technological testing of ""Ta-Nb""
ore from Congo. The results showed that the examined samples have appropriate characteristics for further
technological tests
Utilization of corn biomass waste for adsorption of metal ions: a sustainable approach for water decontamination
No full textAdsorption is flexibile and effective technique that is used to remove pollutants from contaminated water. Agricultural waste and biomass have drawn interest among the many materials being investigated for this purpose because of their efficacy, sustainability, and accessibility. After rice and wheat, corn (Zea mays L.) is one of the most extensively grown crops worldwide. Corn generates a lot of agricultural waste in addition to its important uses as food, animal feed, and a raw material for industry. Despite being frequently seen as a byproduct, this agricultural waste material is a valuable resource because of its quantity and distinct chemical structure. Both raw and processed maize biomass has significant potential as an adsorbent for removal of toxic materials from water.
In order to improve adsorption characteristic, corn waste can be converted into a material with improved adsorption capacities through chemically modification, carbonization, and composite forms. Each of these forms has unique benefits. It has been demonstrated that these adsorbents are efficient at removal of different pollutants from contaminated water, especially metal ions. Furthermore, use maize biomass to treat water is consistent with green chemistry and the circular economy, which support environmentally friendly and sustainable waste management methods. The many adsorbent forms made from maize biomass are thoroughly examined in this review, with an emphasis on their adsorption mechanisms, including chemisorption, surface adsorption, and ion exchange. Additionally, the report highlights the expanding relevance of corn waste and offers future research options while discussing the most recent findings in the sector
Zlato u arsenopiritu i skoroditu iz Gokčanice
No full textPoslednjih godina došlo je do značajnog rasta potražnje za zlatom, kao i proizvodnje istog, na globalnom nivou. Velika potreba za ovim plemenitim metalom uzrokovala je brz razvoj industrije zlata, a samim tim dovela i do postepenog iscrpljivanja resursa rude zlata. Kao posledica toga bilo je potrebno okrenuti se alternativnim izvorima, prvenstveno refraktornim, od kojih jedan predstavlja rudnički otpad nastao preradom polimetaličnih sulfidnih ruda. Prerada ovog otpada i jalovine sa umerenim do niskim sadržajem zlata pokazuje potencijal kako u ekstrakciji ovog metala, tako i u poboljšanju kvaliteta okolnog okruženja.
Jedan od najinteresantnijih refraktornih minerala nosioca zlata i svakako najizazovijih u smislu ekstrakcije istog je arsenopirit. Arsenopirit je dominantni sulfidni mineral u rudnoj mineralizaciji Gokčanice (Drenjak), dok je skorodit glavni sekundarni mineral nasto oksidacijom arsenopirita. Dimenzije jediničnih ćelija arsenopirita izmerene su XRPD metodom. Pojave zlata u arsenopiritu i skoroditu analizirane su metodom optičke mikroskopije u odbijenoj svetlosti (OM), SEM-EDS i TEM metodom. Utvrđeno je da se u oba pomenuta minerala čestice zlata javljaju u formama mikrometarskog „vidljivog“ i nanometarskog „nevidljivog“ zlata
Characterization and thermal decomposition of cerussite
No full textDue to its physical characteristics, lead is one of the most important non-ferrous metals in the world. Metallic lead and its alloys have significant applications in the mechanical industry, radioactive protection, battery industry, as well as in many other industries. In most cases, lead is found in nature in the form of sulphide minerals (galena), as well as in the form of carbonate minerals (cerussite). The aim of this work is to characterize the initial sample of cerussite, as well as its thermal decomposition. Physico-chemical characterization was done by ICP-AES and XRD methods. It was observed that the most abundant phase in the initial sample is PbCO3 (89%), while CaCO3 (7%) and PbS (4%) are present in a very small amount. Thermal decomposition of the sample was performed at a temperature of 900 °C, at a heating rate of 3 ºC/min. It was established that the decomposition of PbCO3 occurs first, followed by the transformation of PbS into PbSO4, and at the very end of the process, the decomposition of CaCO3 occurs
Physicochemical characterization and stability of biochars intended to be applied as soil amendments
No full textWaste biomass (WB) represents renewable resource that can be used in solving complex energy/environment demands. Possible route of WB revalorization is its thermochemical conversion into the biochar, which has remarkable potential as sustainable tool in biomass waste disposal issue, climate change mitigation, and soil environment protection. In this paper, four types of biochar were obtained by WB pyrolysis with intention to be applied as soil amendments. For that purpose, biochar samples were characterized according to Test Category A: Basic Utility Properties requirements according to the International Biochar Initiative (IBI). Analyses included basic properties required to assess the utility of biochar material for use in soil, such as physical properties of particle size and moisture, as well as the chemical properties of elemental proportions obtained from elemental organic analysis (EOA), ash proportion, electrical conductivity, pH and liming ability. Carbon stability was calculated from molar ratios of both H/C and O/C, as well as from proximate analysis results. EOA results shown that all investigated biochars have high content of carbon, ranging from 62.5 to 68.4, classifying them in Class 1 materials. Values of pH ranged between 7.68 and 8.99 indicating alkaline nature of biochars with potential for remediating acidic soils. Calculated H/C ratio was around 0.04 for all samples, while the O/C ranged between 0.40 and 0.54, indicating that biochars pose stable structure and high carbon sequestering potential. Electrical conductivity values showed benefits of biochars incorporation into the soil and valuable agronomic implications, offering beneficial soluble salts content
Nanomechanical Response of Single-Crystalline Titanium at High Temperatures: A Molecular Dynamics Study
No full textTitanium (Ti), a metal with a hexagonal close-packed structure, exhibits outstanding mechanical and thermal
properties, making it ideal for applications in extreme environments. Structural integrity at elevated
temperatures has been extensively studied through experimental mechanical testing. In recent years,
computational modeling has provided critical insights into its plastic deformation mechanisms across different
temperatures as a complement to experimental data. In this work, we employ molecular dynamics simulations
to investigate the mechanical response of single-crystalline Ti under nanoindentation using a rigid spherical
diamond indenter (R = 12 nm) in the 10–900 K range. The empirical interatomic potential for simulating the
mechanical response of single-element materials was chosen by considering the generalized stacking fault
energy and slip dissociation pathways responsible for stacking fault formation and dislocation activity during
mechanical loading. Atomic strain mapping was used to visualize the evolution of plastic deformation beneath
the indenter at elevated temperatures. Nanoindentation simulations reveal the development of pile-ups and
changes in the surface morphology induced by dislocation motion at different temperatures. The obtained
results provide fundamental insights into temperature-driven changes in dislocation dynamics, slip
mechanisms, and local hardness, enhancing understanding of Ti’s thermomechanical stability. These findings
contribute to the design and optimization of Ti-based materials for high-temperature structural applications