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Innovative oxidative system for leaching of Fe2+ from sphalerite concentrate
No full textSphalerite is a sulfide zinc mineral, which also contains supporting metals such as iron, copper and lead.
In this work, we dealt with the extraction of iron from sphalerite in a new oxidation system. Manganese
dioxide was used as the primary oxidant, and KI was used as a secondary oxidizing agent with the aim of
creating an I2/I- oxidation cycle in a sulfuric acid medium. The thoughtful characterization (XRD, SEM,
EDS) of the initial sample, as well as the precipitate formed after leaching was done. During the leaching
tests, process parameters were varied
The effect of fluxing agent cations in fly ash-based glass on chemical stability
No full textRecycling plays a key role in making the economy more efficient in terms of raw material usage.
Coal fly ash (CFA), a by-product of coal combustion in thermal power plants, shares a chemical composition
similar to some silicate glasses, making it a viable raw material for glass production. The paper presents the
results of Na+ and Ca2+ ion incorporation into coal fly ash-based glass and its impact on chemical stability. The
chemical resistance of the glasses was tested in distilled water, 0.01 mol/dm3 HCl, and 0.01 mol/dm3 NaOH.
The concentrations of the elements in the solution indicate that the ion exchange process is the dominant
dissolution mechanism for both glasses. Na-fly ash glass shows slightly lower stability in all solvents than Ca-fly
ash glass. FTIR spectra show no change in the structure of the glasses after contact with solvents. The chemical
stability of both glasses is satisfactory with a mass change of less than 1 %
Synthesis of tin sulfide using high exothermic reaction
No full textBecause 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
SEM-EDX characterization of iron-modified plum stones biochar
No full textIt has been shown that biochar, an inexpensive and eco-friendly material made by pyrolyzing biomass, has the ability to eliminate pollutants from water and wastewater. The efficacy of raw biochar as adsorbent and catalyst in advanced oxidation processes is limited, but it is significantly increased by modification. Various physical and chemical methods employed before, during, or after biochar production is among the many that have been investigated. By adding iron compounds, biochar's surface area is increased and new contact points are formed, improving its capacity for adsorption. Iron-biochars are valuable due to their exceptional ability to remove pollutants. Iron functionalized biochar prepared by post-pyrolysis surface Fe modification of plum stones. In this study, SEM-EDX analysis was performed to determine the surface morphology and elemental composition of plum stones biochar and FeCl3 impregnated biochar. After coprecipitation with Fe salt, Fe-BPS showed irregular structure with improved porosity. Content of iron significantly increased in Fe-BPS. Iron-based biochar's adsorption ability and catalytic activity work in concert to remove pollutants from wastewater via two mechanisms. Therefore, iron is added to the plum stone biochar to increase its adsorption capacity and reactivity, which makes it possible to remove a variety of organic and inorganic pollutants efficiently
Position of copper within urban mining - recovering potential from mine tailings
No full textDue to population growth and urbanization, accompanied by rapid technological development, the need for more material resources has multiplied. Demand for specific materials is growing particularly fast. One of these minerals is copper. Besides its quality for conducting electricity, this metal is crucial to a greener world. It founds application in managing electric vehicles, smart grids, and renewable energy systems. A wide span of its utilization requires an adequate and continuous supply of copper. A key solution for this lies in urban mining, which implies reusing and recovering raw materials from waste materials in the technosphere. One type of free voluminous waste that is difficult to dispose of safely is tailing ponds, an additional reason for recycling. Recycling copper from tailing ponds is an economically and environmentally acceptable form of waste reuse based on the principles of the circular economy by using already disposed waste, reducing current and future pollution, reducing remediation costs, and converting toxic waste into a free resource
Thermally Activated Plasticity in Single-Crystal Titanium: A Molecular Dynamics Study of Nanoscale Deformation
No full textHexagonal close-packed (hcp) titanium exhibits a complex temperature-dependent mechanical response that is
central to its use in structural applications. We employ large-scale molecular dynamics simulations to investigate
the nanoindentation behavior of single-crystalline α-Ti along the [0001], [10̅10], and [2̅110] orientations at 10,
300, and 600 K. The simulations reveal how temperature modifies the onset of plasticity and the subsequent
evolution of dislocation activity, including nucleation, glide, and the competition between basal and pyramidal
⟨c+a⟩ slip. Schmid factor mapping establishes a direct correlation between the orientation-dependent activation of
slip systems and the resolved shear stress fields beneath the indenter. The results demonstrate a pronounced increase
in thermally assisted dislocation motion with temperature, which manifests as diffuse slip traces and less localized
pile-up patterns. Surface morphologies obtained at 300 K are consistent with atomic force microscopy
observations, validating the atomistic modeling approach. At elevated temperatures, enhanced dislocation recovery
and redistribution of slip pathways dominate the indentation response, highlighting the role of thermal activation
in controlling plasticity in hcp titanium
Waste peels as source for greener materials: Treatment of dye wastewater
No full textAquatic and terrestrial species may be negatively impacted by the widespread use of synthetic dyes in several industrial sectors. Examining the photodegradation and photocatalytic characteristics of recently produced biobased TiO2 (Ac-bTiO2) particles were the goal of this study. Citrus plant extracts have a number of bioactive ingredients that may be useful as reducing or capping agents. Specifically, titanium alkoxide and aqueous extract of mandarin peels were cross-linked under carefully regulated reaction conditions to create a photocatalyst. Various techniques (SEM, EDS, XRD and UV-DRS) were applied to determine structural and morphological properties of obtained particles UV-Vis spectroscopy was used to quantify photocatalytic activity under simulated sunshine circumstances. Methyl orange solution was utilized as a model pollutant for determination of photocatalytical activity of fabricated biobased particles. After 60 min, complete decolorization was seen, while the degradation kinetics followed pseudo-first order (R2 > 0.98). Under operating conditions, a satisfactory rate of photocatalyst degradation indicated the potential of successive, multicycle utilization and further possibility for using synthesized materials into various wastewater treatment plants
Insights into the Glass Network Structure of Coal Fly Ash-Based Glass
No full textCoal fly ash is the by-product of coal combustion in thermal power plants. The chemical composition of
coal fly ash allows it to be utilized as a secondary raw material for glass production. Na2CO3 and CaCO3
were introduced in the batch as raw materials for glass network modification. Dark homogenous glass was
obtained by melting the batch and quenching it on the stainless steel in the air. This research investigates
the relative share of structural units of the glass network by deconvolution of the part of the FTIR spectra.
Results show that most dominant structural units contain one and two bridging oxygen per [SiO4]
tetrahedral indicating low glass network connectivity
Behavior of plant micronutrients (Fe, Cu) during combustion of contaminated Sorghum spp.
No full textForage sorghum (Sorghum spp.) is a fast-growing annual plant that contains certain micronutrients, the
most abundant of which is iron, and the least abundant is copper. This paper presents the behavior of these
two micronutrients in sorghum species during combustion at different times and temperature conditions.
Combustion of the homogenized sample was performed at temperatures of 400 °C, 450 °C, 500 °C and
600 °C in times of 120, 240 and 360 minutes. Differential thermal analysis (DTA) is carried out at a heating
rate of 3 K/min from 25 to 500 °C. It was found that the combustion of forage sorghum increased the
concentration of these two micronutrients in it. The highest concentration of Fe (7777 mg/kg) was achieved
after 360 minutes of combustion at 600ºC, while the highest concentration of Cu (105 mg/kg) was achieved
after 240 minutes of combustion at 450ºC
Evaluating the influence of temperature on metal concentrations in bottled water contained in PET Packaging
No full textThe safety of bottled water depends not only on the chemical composition of the content but also on the
influence of packaging and storage conditions. This study aimed to investigate the effect of temperature
on the concentration of metals in bottled water packaged in PET containers. Samples from six
commercial brands on the domestic market were analyzed under three temperature conditions: -20°C,
25°C, and 40°C. Quantitative analysis of 18 elements was performed using ICP-MS, with a particular
focus on toxic metals: antimony (Sb), cadmium (Cd), and lead (Pb). The highest concentration of
antimony was recorded in “Knjaz Miloš” water at 40°C (15.59μg/L), significantly exceeding the
maximum allowed concentration for drinking water (5μg/L, EU and EPA standards). Cadmium was
detected in most samples, with the highest value observed in Voda “Voda” at -20°C (0.50μg/L). In most
brands, a decrease in cadmium concentration was observed with increasing temperature, suggesting a
possible inverse temperature trend, although inconsistent across all samples. Trace levels of lead were
found in multiple samples, with a maximum of 1.76μg/L. A weak positive correlation between
temperature and the concentrations of Sb, Pb, and Cu was observed, indicating a potential temperature induced migration of certain elements from the packaging. In addition to health-relevant elements,
strontium (Sr), lithium (Li), and barium (Ba) stood out due to high variability in concentration across
brands. Their stable presence and significant inter-brand differences suggest their potential application
as markers of geological origin and water source type. The results emphasize the importance of
monitoring the storage conditions of bottled water and the need for further investigation into the
chemical stability of PET packaging under varying temperature conditions