Search Results (2,042)

Magnetite is extensively developed within various alteration zones of the mining district. Some magnetite is closely associated with copper mineralization, possessing significant research value. The Duobuza Cu (Au) deposit is a typical porphyry-type deposit within the Bangong Co-Nujiang metallogenic belt and was the first porphyry Cu-Au deposit discovered in the Duolong copper–gold ore district. Currently, this deposit contains copper resources exceeding 3 million tons @0.46%, with associated gold resources exceeding 80 tons @0.19 g/t. This study focuses on magnetite from the Duobuza deposit. Through field geological logging and microscopic identification combined with electron microprobe analysis (EMPA) and in situ LA-ICP-MS testing, mineralogical and mineral chemical research on magnetite is conducted. This research aims to elucidate the genesis of magnetite in the Duobuza deposit and its implications for mineral exploration. Five magnetite types with different occurrences can be distinguished in the Duobuza deposit: Mt₁ is magmatic magnetite; Mt₂, Mt₃, Mt₄, and Mt₅ are hydrothermal magnetite, with Mt₅ being closely associated with copper mineralization. Mt₁ is relatively enriched in Ti, V, Al, and Cr but depleted in Mn and Si; Mt₂ is relatively enriched in Ti and Al but depleted in Si and Cr; Mt₃ is relatively enriched in Al but depleted in Mg; Mt₄ is relatively enriched in Ti, Al, V, Zn, and Mn; and Mt₅ is relatively enriched in Mg, Si, Ti, Al, Mn, and Zn but depleted in Cr. Based on the Al + Mn vs. Ti + V discrimination diagram, magnetite formed in a medium- to high-temperature environment, with hydrothermal magnetite Mt₄ forming at the lowest temperature. Vanadium (V) content can be used to estimate the oxygen fugacity (fO₂) during mineralization. Mt₁ exhibits the highest V content, indicating relatively low oxygen fugacity, whereas Mt₄ shows the lowest V content, suggesting relatively high oxygen fugacity. Mt₅ has a higher V content compared to other early-stage hydrothermal magnetites, suggesting that a lower fO₂ formation environment favors the precipitation of metal sulfides in the mining district. Trace element analysis of magnetite from the Duobuza, Bolong, and Naruo mining districts reveals that magnetite from all three deposits is enriched in Si and Al and depleted in Ca and Ni. Magmatic magnetite from the Naruo and Duobuza deposits exhibits similar elemental distribution patterns. Hydrothermal magnetite from the Duobuza deposit shows significantly higher Ti and V contents compared to magnetite from the Bolong and Naruo deposits. Full article

Drought stress induces the excessive accumulation of hydrogen peroxide (H₂O₂), leading to oxidative damage and reduced crop productivity. This study presents a dual-function nanotechnology-based strategy for monitoring and mitigating drought-induced oxidative stress in cereal crops. Hierarchical CuO nanostructures were grown directly on copper substrates by hydrothermal oxidation, and the influence of growth time on morphology and hydrogen peroxide sensing performance was systematically evaluated. An optimal growth time of 3 h produced CuO nanoflower architectures with high surface area, yielding superior electrocatalytic activity toward H₂O₂ detection, with a low detection limit of 1.9 µM and high sensitivity of 11.92 mA·mM⁻¹·cm⁻². The optimized sensor enabled reliable quantification of H₂O₂ in oat (Avena sativa) and rye (Secale cereale) under drought stress, revealing species-dependent oxidative responses. In parallel, magnesium oxide (MgO) nanoparticles effectively alleviated drought-induced oxidative damage, reducing H₂O₂ accumulation by up to 63% in oat and 61% in rye and significantly improving plant growth and chlorophyll content. The integration of CuO-based sensing with MgO nanoparticle-assisted stress mitigation provides a robust framework for plant stress diagnostics and intervention, highlighting the potential of nanotechnology-enabled strategies for crop stress diagnostics and precision agriculture. Full article

In this study, the corrosion behavior of Cu_XCoCrMoNi (x = 0.3, 0.6, 0.9) high-entropy alloys (HEAs) in 3.5% NaCl solution is systematically investigated. The alloy samples show a strong link between copper content and corrosion resistance. It is noteworthy that an increase in copper content promotes element segregation, resulting in an increase in corrosion current density from 2.138 × 10⁻⁷ μA/cm² to 1.8989 × 10⁻⁶ μA/cm² and a decrease in charge transfer resistance from 182.6 Ω·cm² to 42.34 Ω·cm². In addition, electrochemical experiments demonstrate that lowering the copper content in the alloys reduces the spread and depth of corrosion. All alloys exhibit n-type semiconductor behavior, with donor density increasing from 4.792 × 10²³ cm⁻³ to 5.581 × 10²³ cm⁻³ with increasing copper content. Notably, the passive film is characterized by the presence of Cr₂O₃ and Cu₂O as its main constituents. As the copper content in the HEA increases, higher levels of copper oxides in the passive film inhibit the formation of chromium oxides. This degrades the passive film quality, thereby diminishing the overall corrosion resistance. Full article

The geoelectrochemical extraction method is effective for locating deep concealed deposits, but research on the particle size distribution of its anomaly-causing substances remains limited. To address this, 20 sampling points were established along the No. 20 exploration profile at the Tongjiangling Copper Deposit in Jiangxi Province. Using consistent technical conditions, geoelectrochemical measurements were compared across filter membranes/papers with pore sizes of 0.22 μm, 0.45 μm, 1 μm, 3 μm, and qualitative medium-speed filter paper (approx. 20–30 μm). The results are as follows: (1) The 20–30 μm filter paper effectively detected anomalies corresponding to both shallow and deep concealed ore bodies, whereas smaller pore sizes only revealed shallow ore bodies. (2) Element content and anomaly contrast were significantly higher with the 20–30 μm filter paper compared to smaller pore sizes. (3) Geoelectrochemical anomalies originate from various surface soil substances, which may exist independently or be adsorbed onto particles of different sizes. The applied electric field mobilizes these charged particles, enabling their adsorption onto the collector and acquisition of deep mineralization anomalies. (4) For similar landscapes and deposit types, using filter paper with a pore size of approximately 20–30 μm is recommended to effectively capture deep ore body anomalies while reducing analytical complexity. Full article

The current transition from conventional blast furnaces to electronic arc furnaces is a viable path to reducing CO₂ emissions during steel production. However, this transition of technologies changes the requirements for possible scrap that may be used as a secondary raw material during EAF steel production. Copper is especially challenging, as it remains in the melt, reducing the mechanical properties of the produced crude steel while being lost to any secondary use. Currently, the two main routes to reduce the copper content are X-Ray Fluorescence sorting and manual sorting. We propose a third approach by using computer vision and machine learning methods to detect copper-containing particles in a post-shredder scrap fraction on low-cost and low-powered hardware. Furthermore, this proposed method is robust to environmental factors, such as heavily corroded particles caused by prolonged storage without proper weather protection. This method can effectively reduce the need for expensive XRF equipment or manual sorting. The developed sorting pipeline was examined in an industrial setting through sorting trials and achieved 99.9 wt.% purity in the produced iron fraction at throughputs of over 3 t/h. Full article

Copper smelting slags represent a growing environmental and metallurgical challenge due to their large volumes and their content of unrecovered critical metals such as copper. Although conventional treatment relies mainly on acidic leaching, more sustainable hydrometallurgical routes are required to valorise these residues. In this study, an alternative copper extraction process is proposed based on alkaline glycine complexation and the use of ferromanganese crusts as an unconventional oxidising agent. Leaching tests were performed using two slags (A and B) at ambient conditions. Copper recoveries up to 59.7% (slag A) and 25.7% (slag B) were achieved at 1 M glycine without external oxidants. The addition of ferromanganese crusts (1:1 and 2:1) resulted in marginal increases (up to 61.1% and 29.1%, respectively), attributed to the limited oxidative performance of MnO₂ at near-neutral pH. The results demonstrate that glycine is a viable lixiviant for copper recovery from slags at room temperature and highlights, for the first time, the use of naturally occurring Fe–Mn crusts as oxidants in alkaline leaching systems. This work contributes to the development of more sustainable valorisation strategies for metallurgical slags and offers a basis for future optimisation of alkaline complexation routes. Full article

Bismuth oxychloride (BiOCl)– copper oxide (CuO) heterostructures were synthesized via a solvothermal route and assessed as visible-light-driven photocatalysts for methyl orange (MO) degradation. Different CuO loadings deposited on BiOCl microspheres were investigated to identify the optimal composition. Structural and physicochemical characterization revealed that low CuO content (0.6 wt. %) promoted uniform dispersion and enhanced surface area, whereas higher loadings led to nonuniform coverage and reduced photocatalytic efficiency. Operating conditions were optimized using response surface methodology based on a central composite design, considering catalyst dosage (0.1–0.8 g L⁻¹) and pH (4–9). The highest degradation efficiency (~50% after 60 min irradiation) was achieved at pH = 4 and a catalyst dosage of 0.8 g L⁻¹ using the BiOCl surface modified with 0.6% CuO. Kinetic analysis followed a pseudo-first-order model. Mass spectrometry identified transient intermediates associated with demethylation and desulfonation pathways, while radical scavenger experiments confirmed hydroxyl radicals (^•OH) as the dominant oxidizing species, with a secondary contribution from superoxide radicals (^•O₂⁻). These results highlight the critical role of CuO dispersion and interfacial quality in enhancing charge separation and photocatalytic performance, providing practical guidelines for the rational design of BiOX-CuO heterostructures for water remediation applications. Full article

Using plants to restore soils subjected to salinization and polychemic pollution can be an effective way to return agricultural land to circulation and obtain safe products. In this study, experiments were conducted with oats and lupine to evaluate their ability to purify soils contaminated with copper (II) and nickel (II) ions, carbonate and sulfate anions and oil and their combinations. The biological activity of the soil, phytotoxicity, and hydrocarbon content, as well as plant growth and biochemical parameters in polluted soil, were studied. The enzymes most sensitive to soil contamination were catalase, urease, and phosphatase. Copper ions inhibited oat root growth by 45.7% and lupine by 46.6%. Oil and its mixtures with other pollutants inhibited shoot growth by up to 50.3% in oats and up to 28.6% in lupine. The content of malonic dialdehyde increased in oats when exposed to copper, while in lupines, it increased 2.9-fold when exposed to oil. Flavonoids in oats increased with metal contamination (by 9–16.7%), while in lupines with oil (by 8.6%). Chlorophyll fluctuations were less pronounced in oats than in lupine. Despite the stress experienced by plants due to soil pollution, the degradation rate of petroleum hydrocarbons under oat and lupine crops was 33–46%. In general, oats and lupine are promising for the phytoremediation of complexly polluted and saline soils. Full article

Magnesium alloys require protective surface coatings for widespread application, with micro-arc oxidation (MAO) being a prominent technique. However, conventional MAO coatings are typically gray or light-colored, necessitating secondary treatments for specific colors like black, which complicates the process. This study aims to develop a one-step method for fabricating black MAO coatings on AZ31 magnesium alloy by introducing cupric pyrophosphate (Cu₂P₂O₇) as a colorant into a silicate-based electrolyte. As the Cu₂P₂O₇ concentration increased from 0 to 5 g/L, the coating color transitioned from grayish-white to pink, then brownish-black, achieving a uniform black appearance at 4–5 g/L. XPS and EDS analyses confirmed the incorporation of copper as CuO, identified as the primary coloring agent. XRD indicated that the phase composition remained MgO, MgSiO₃, and Mg, although the MgO content decreased. Microstructural analysis showed that an optimal concentration of 4 g/L enhanced coating compactness by thickening the dense layer and reducing pore size. However, electrochemical tests revealed that the incorporation of CuO significantly increased the corrosion current density, thereby reducing the coating’s corrosion resistance compared to the unmodified coating. This work successfully demonstrates the one-step fabrication of black MAO coatings, elucidates the coloration mechanism involving CuO formation, and provides insights into the trade-off between aesthetic functionalization and corrosion performance. Full article

Amphiphilic copolymers based on polystyrene and polyglycidol combine the chemical inertness of polystyrene with the biocompatibility of polyglycidol, making them attractive materials for polymeric micelles. While comb-like architectures have been explored to control micellization behavior and biological response, a direct comparison between comb-like and coil-comb topologies in polystyrene–polyglycidol copolymers at identical polyglycidol content remains insufficiently investigated. In this work, amphiphilic comb-like and coil-comb polystyrene–polyglycidol copolymers were synthesized via copper-catalyzed azide–alkyne click chemistry by grafting a monoalkyne-terminated polyglycidol precursor onto azide-functionalized random and block styrene copolymers. The copolymers were characterized by size exclusion chromatography and nuclear magnetic resonance. Polymeric micelles were prepared by nanoprecipitation, and their self-assembly in aqueous solution was investigated by critical micelle concentration determination, dynamic and electrophoretic light scattering, and atomic force microscopy. Both copolymers formed stable aqueous dispersions and exhibited comparable critical micelle concentrations. At identical polyglycidol content, the random copolymer formed a uniform, monomodal micellar population, whereas the block-based coil-comb architecture led to bimodal size distributions, indicating the coexistence of two distinct micellar populations. The investigated systems showed low cytotoxicity and did not induce significant oxidative stress within the studied concentration range. On isolated rat brain sub-cellular fractions (synaptosomes, mitochondria and microsomes), administered alone, the comb-like and coil-comb polystyrene-polyglycidol copolymers did not reveal statistically significant neurotoxic effects. The results demonstrate that macromolecular architecture plays a key role in governing micellar organization and in vitro biological response in polystyrene–polyglycidol copolymers, highlighting their potential as architecture-controlled polymer-based nanocarriers. Full article

This study presents the electrochemical characterization of a novel, binder-free, plasma-treated aluminum/carbon electrode (“Surge”) using lithium metal half-cells. The low operating potential near 0 V vs. Li/Li⁺ enables the investigation of the electrode’s charge storage mechanisms and stability limits. We compare its electrochemical behavior in coin cells (CR2032) against two reference configurations: (i) the Surge electrode with a thin copper backer (Surge + Cu-backer) and (ii) a commercial graphite electrode on an aluminum current collector (C-REF). The Surge electrode demonstrated ultra-high initial specific capacities of up to approximately 4500 mAh/g (cycle 1) with Coulombic efficiencies exceeding 85% after the formation cycle. The observed capacity significantly exceeds the theoretical value for Li-Al alloying (993 mAh/g), indicating that lithium plating within the porous carbon scaffold contributes substantially to the total charge storage. However, this high performance was limited to approximately 8 to 9 stable cycles. Post-cycling analysis via scanning electron microscopy combined with energy-dispersive X-ray spectroscopy (SEM/EDX) revealed a dominant failure mechanism: partial dissolution and consumption of the Al current collector leading to material redistribution. Quantitative EDX analysis showed a decrease in Al content from 45 at.% to 12 at.% alongside an increase in oxygen content from 8 at.% to 38 at.%, suggesting extensive Al-oxide formation. Critically, in the absence of a backer, Al-containing material deposited onto the stainless-steel cell components. The Cu backer served to redirect these deposits, improving current collection and modestly extending the short-term durability to approximately 1800 mAh/g at cycle 14 (approximately 75% capacity retention). In contrast, the C-REF control cell reached only approximately 1000 mAh/g (cycle 4) before failing within 5 to 6 cycles, underscoring the inherent instability of bare Al at low potentials. This characterization study establishes the Surge architecture as a successful proof-of-concept for ultra-high capacity charge storage and identifies Al dissolution as the dominant degradation mechanism. Future optimization must focus on stabilizing the Al substrate through protective interphases, alloying, or electrolyte engineering. Full article

We have investigated the major- and trace-element composition of hydrothermal pyrite, magnetite, and Ti-magnetite, and of the principal Cu-minerals chalcopyrite and chalcocite, to constrain ore-forming processes in the northeastern Saveh district (central Urumieh–Dokhtar magmatic arc, Iran). Our data provide new constraints on the magmatic–hydrothermal evolution and subsequent hydrothermal–supergene modification of the ore system. Ti-magnetites hosted in monzodioritic intrusions are enriched in Ti–V–Al, plot below the magnetite–ulvöspinel join and record high crystallization temperatures (<500 °C) under relatively low oxygen fugacity. By contrast, magnetite from silica-rich hydrothermal veins is Fe-rich with very low TiO₂; it formed at intermediate temperatures (~200–300 °C) under higher fO₂ and is markedly depleted in Ti and V compared with the intrusive oxides. Textures and oxide systematics (Al + Mn vs. Ti + V; V/Ti–Fe) document repeated hydrothermal pulses, Fe²⁺ leaching and element redistribution during cooling and fluid–rock interaction. Geochemical trends indicate progressive evolution from a magmatic fluid to later meteoric water overprint, with increasing As contents reflecting cooling and mixing with meteoric waters. Vertical elemental zoning suggests that most samples represent mid- to deep-level sections of the epithermal system. Elevated Cu contents (up to 0.95 wt.%) highlight pyrite as a significant Cu host. Co/Ni ratios between 1 and 10 further corroborate a magmatic–hydrothermal origin. Chalcopyrite is the principal economic Cu carrier at Northeast Saveh. Replacement follows a temperature- and fluid-controlled pathway (chalcopyrite → covellite → chalcocite). At lower temperatures (<~200 °C) replacement proceeds more slowly, producing chalcocite/digenite under prolonged reaction conditions. Chalcocite commonly occurs as thin replacement rims and fracture fills that concentrate remobilized copper. Collectively, the investigated oxide and sulfide proxies provide robust discriminants for separating magmatic versus hydrothermal domains and for vectoring toward higher-temperature feeders and zones of remobilized copper. Full article

Agile and flexible resource modelling is essential for informed decision-making in early-stage mineral project assessment, and in more advanced stages, particularly when compared with conventional deterministic geological modelling and single-estimate resource evaluations. This study presents a case of rapid scenario generation to view, interpret and test the impact of alternative geological and modelling assumptions, including the definition of geological domains, geological interpretation, grade estimation within domains, and the associated uncertainty. The workflows are implemented in Annapurna™ Resource, a cloud-native geostatistical platform designed to support agile, advanced, and multivariate modelling workflows. Focusing on the multi-commodity San Antonio–Potrerillos district, we demonstrate how rapid model construction enables the systematic evaluation of geological and statistical assumptions, contrasting deterministic estimates with probabilistic outcomes and testing their impact on estimated grades and tonnage under multiple scenarios for five elements: copper (Cu), molybdenum (Mo), gold (Au), silver (Ag), and arsenic (As). The approach provides quantitative measures of model reliability, identifies areas of high uncertainty, and supports the prioritization of new drilling to improve geological knowledge, exploration targeting, and resource classification. This case study highlights the value of fast-turnaround, probabilistic modelling not as a replacement for traditional resource reporting, but as a decision-support framework that enhances understanding of the geology, tests the sensitivity of assumptions, and accelerates learning throughout exploration and into operations. The main results suggest that additional drilling can be strategically placed to reduce the geological uncertainty derived from comparing the current interpretation with the probabilistic model built with indicator kriging. Furthermore, this has relevance in reducing the risk in the assessment of the metal content in each area of the deposit. Sensitivity analysis performed over key parameters of the estimation suggests that outliers’ treatment is the most impactful step during estimation. With current technological tools, it is possible to maintain a live resource model, which can be continuously updated to assess the impact of new data and decisions in near real time. Full article

Trifoliate orange (Poncirus trifoliata L.) is one of the most widely utilized rootstocks in citrus production; however, it exhibits a relatively high sensitivity to salt stress. When cultivated in salinized soil, it frequently develops nutrient uptake disorders, leaf chlorosis, as well as reduced fruit yield and quality. To enhance the salt stress tolerance of citrus plants, this study investigated the effects of Trichoderma harzianum inoculation on the growth and response mechanisms of citrus seedlings under salt stress conditions. The results showed that salt stress significantly inhibited the growth of citrus seedlings, while T. harzianum inoculation effectively alleviated the inhibitory effect. After treatment with T. harzianum, the plant height, stem diameter, leaf number, and biomass of citrus seedlings increased significantly. The net photosynthetic rate, stomatal conductance, intercellular CO₂ concentration, transpiration rate, and chlorophyll content were significantly increased by T. harzianum inoculation. Meanwhile, T. harzianum inoculation increased the content of nitrogen, phosphorus, calcium, magnesium, zinc, and copper, and decreased sodium content in citrus seedlings. In addition, T. harzianum inoculation significantly up-regulated the expression of stress-responsive genes such as SOSs, PIPs, TIP1, TIP4, and TIP9. In conclusion, T. harzianum inoculation improved the salt stress tolerance of citrus seedlings through increasing photosynthetic efficiency, promoting nutrient absorption, sodium efflux, and water utilization via up-regulating the expression of SOSs and aquaporin genes. Full article

Garlic (Allium sativum L.) is a significant crop cultivated worldwide for its culinary, nutritional, and medicinal value. This study aimed to evaluate the effects of different fertilization regimes on the bioactive compounds, antioxidant activity, nutritional value, and mineral composition of garlic. The field experiment was conducted at the Institute of Field and Vegetable Crops, in three replications. Fertilization significantly influenced the bioactive compounds, antioxidant activity, nutritional quality, and mineral composition of garlic. Cattle manure proved to be the most effective treatment, increasing protein (by approx. 5.1%), total sugars (17.9%), sucrose (24.9%), sulfur content (7.2%), total phenolics (3.1%), flavonoids (30.7%), and antioxidant activity (by 5.2–23.1% depending on the assay) compared to the control, indicating superior nutritional and functional quality. Multivariate analyses highlighted the significant impact of fertilization regimes on garlic quality, with mineral fertilizer, control (treatment without fertilizer application), and cattle manure enhancing bioactive compounds, antioxidant activity, and nutritional composition. Fertilization had limited effects on macroelements, although cattle and sheep manure increased nitrogen and sulphur contents, while molasses reduced phosphorus and potassium levels. Organic fertilization significantly modified microelement composition, with sheep manure notably increasing zinc and copper, while most fertilizers reduced boron, iron, and sodium contents compared with the control. Animal-based fertilizers, particularly cattle manure, provide a sustainable alternative to mineral fertilization, enhancing garlic’s dry matter, nutritional and bioactive compounds, and antioxidant activity. Full article