Search Results (866)

In geophysics, aeromagnetic surveying based on unmanned aerial vehicles (UAV) is a widely employed exploration technique, that can analyze underground structures by conducting data acquisition, processing, and inversion. This method is highly efficient and covers large areas, making it widely applicable in mineral exploration, oil and gas surveys, geological mapping, and engineering and environmental studies. However, during flight, interference from the aircraft’s engine, electronic systems, and metal structures introduces noise into the magnetic data. To ensure accuracy, mathematical models and calibration techniques are employed to eliminate these aircraft-induced magnetic interferences. This enhances measurement precision, ensuring the data faithfully reflect the magnetic characteristics of subsurface geological features. This study focuses on aeromagnetic data processing methods, conducting numerical simulations of magnetic interference for aeromagnetic surveys of UAVs with the Tolles–Lawson (T-L) model. Recognizing the temporal dependencies in aeromagnetic data, we propose a Transformer neural network algorithm for aeromagnetic compensation. The method is applied to both simulated and measured flight data, and its performance is compared with the classical Multilayer Perceptron neural networks (MLP). The results demonstrate that the Transformer neural networks achieve better fitting capability and higher compensation accuracy. Full article

Pegmatite ores, the primary and technologically advanced lithium (Li)-bearing minerals, comprise various rare metal-based elements, including niobium (Nb), tantalum (Ta), tin (Sn), and beryllium. With increasing Li demand, global exploitation of pegmatite ores has generated vast tailings, mainly comprising quartz and feldspar. However, the process for comprehensively utilizing valuable minerals from pegmatite ores remains undeveloped, and the persistent gap between laboratory studies and industrial practice hinders the sustainable advancement of the pegmatite mineral processing industry. Herein, a comprehensive utilization beneficiation process was designed and validated at both laboratory- and pilot-scale levels. Locked-circuit flotation tests at the laboratory-scale on spodumene and feldspar yielded (i) an Li concentrate with an Li₂O grade of 5.80% and recovery of 88.62%, and (ii) a feldspar concentrate with a (K₂O + Na₂O) grade of 11.41% and good recoveries of K₂O (81.30%) and Na₂O (84.81%). In a 72 h continuous pilot-scale test, an Li flotation concentrate with an Li₂O grade of 5.72% and recovery of 86.78%, and a final Li concentrate with an Li₂O grade of 5.89% and recovery of 86.56% were obtained. Using Li flotation tailings as feed, a feldspar concentrate with a (K₂O + Na₂O) grade of 11.41% was obtained, achieving K₂O and Na₂O recoveries of >75%. The proposed process realizes nearly overall mineral recovery from the pegmatite ores, producing qualified concentrates of Li, Nb–Ta, Sn, feldspar, and quartz. In water reuse feasibility tests, ferrous sulfate (FeSO₄) was identified as the optimum flocculant at a dosage of 1000 g m⁻³. In the locked-circuit test with returned water, the consumption of sodium hydroxide (NaOH), sodium carbonate (Na₂CO₃), and EMT-12 (collector) was reduced by 18.75%, 3.33%, and 3.45%, respectively, while the flotation indices of the Li concentrate (Li₂O grade of 5.77% and recovery of 86.47%) were slightly lower than those in freshwater. In addition to increasing economic benefits, the process offers considerable reductions in tailings disposal, full utilization of multiple elements, and a potential decrease in water and reagent consumption. This study provides important guidelines for the mineral processing of Li pegmatite and other associated multimetallic ores. Full article

With the continuous development of easily accessible resources, the exploitation of complex mineral resources, metallurgical waste slag containing high-value metals, and secondary resources is gradually becoming a mainstream trend. Due to the complex distribution characteristics of elements in these resources, efficient recycling is difficult to achieve. A phase reconstruction strategy has been proposed to address the distribution forms of elements. The phase reconstruction strategy employs pyrometallurgical methods to subject complex resources to high-temperature smelting and cooling crystallization. In the cooling crystallization process, the target elements in melt are selectively enriched into engineered artificial minerals (EnAMs). Then, the target elements can be recovered by subsequently separating these EnAMs. However, the concept of and design strategies for EnAMs are still unclear. In this review, the concept of EnAMs is proposed based on previous studies. This review explores how to design EnAMs by phase equilibrium studies and utilizing geochemical behaviors. Additionally, the application cases of EnAMs in treating challenging tantalum–niobium and rare earth element (REE) resources, secondary resource recycling, and metallurgical slag were collected. Furthermore, the challenges and future perspectives of EnAMs for complex resources are discussed. Full article

An operational test and degradation analysis of a hydraulic fluid based on synthetic esters was performed in three types of work machines. To enhance its performance, ZDDP anti-wear agents were added. Hydraulic fluids are susceptible to degradation by oxidation; therefore, to ensure the long service life of the equipment, it is essential to monitor their current condition through laboratory analyses during machine operation. Emission spectrometry was used to determine the presence of contaminants and the concentration of additive substances in the oil. Pollution was assessed by cleanliness code analysis according to ISO 4406-2021, alongside Total Acid Number (TAN) analysis and LNF analysis of wear and contamination in lubricants. The combination of cleanliness code analysis and LNF analysis of particle type and origin allows for monitoring not only the count but also the origin of contaminating metallic particles, which increases the probability of correct diagnostics and successful detection and resolution of wear problems. All three machines were still operational at the end of the test interval, meaning the tested hydraulic fluid is a suitable alternative to mineral variants. However, in all three pieces of equipment, it is necessary to replace the hydraulic fluid and flush the system before further operation. Furthermore, we recommend replacing the filter elements and inspecting the internal spaces of rotating parts with an increased potential for wear. From the oil’s perspective, it is advisable to add more anti-wear additives (ZDDP), which are depleted the fastest. Full article

In this study, the thermal and structural behavior of battery module components produced from polymer-based composites was systematically evaluated using coupled Moldflow 2016 and ANSYS Fluent 2024 simulations. Three thermoplastics—metal-flake-reinforced PC+ABS (Polycarbonate/Acrylonitrile Butadiene Styrene), carbon-fiber-reinforced PEEK (Polyether Ether Ketone), and hybrid mineral-filled PP (Polypropylene)—were investigated as alternatives to conventional aluminum components. Moldflow simulations enabled the assessment of injection molding performance by determining injection pressure, volumetric shrinkage, warpage, residual stress, flow front temperature, and part weight. PEEK exhibited the best dimensional stability, with minimal warpage and shrinkage, while PP showed significant thermomechanical distortion, indicating poor resistance to thermally induced deformation. For thermal management, steady-state simulations were performed on a 1P3S pouch cell battery configuration using the NTGK/DCIR model under a constant heat load of 190 W. Material properties, including temperature-dependent thermal conductivity, density, and specific heat capacity, were defined based on validated databases. The results revealed that temperature distribution and Joule heat generation were strongly influenced by thermal conductivity. While aluminum exhibited the most favorable thermal dissipation, PC+ABS closely matched its electrical performance, with only a 1.3% lower average current magnitude. In contrast, PEEK and PP generated higher cell core temperatures (up to 20 K) due to limited heat conduction, although they had comparable current magnitudes imposed by the energy-conserving model. Overall, the findings indicate that reinforced thermoplastics, particularly PC+ABS, can serve as lightweight and cost-effective alternatives to aluminum in mid-range battery modules, providing similar electrical performance and thermal losses within acceptable limits. Full article

High-temperature sintering for ceramsite preparation is a safe and effective approach to recycle solid waste. Flux components are critical in ceramsite sintering, as they can reduce sintering temperature, modulate the viscosity and content of the liquid phase, and ultimately optimize ceramsite performance. However, existing studies on lead–zinc tailings (LZTs) and coal gangue (CG)-based ceramsite lack systematic exploration of key fluxes (Na₂O, MgO, CaO, Fe₂O₃), limiting the high-value utilization of these wastes. Under fixed sintering conditions (preheating at 400 °C for 30 min, sintering at 1250 °C for 30 min, heating rate of 10 °C/min), this work systematically investigated the effects of these fluxes (in the forms of carbonates, except for Fe₂O₃) on LZTs-CG ceramsite. The mechanical properties, mineral composition, microstructure and heavy metal leaching of samples were analyzed using various methods, including uniaxial compression, X-ray diffraction (XRD), scanning electron microscopy (SEM), and inductively coupled plasma optical emission spectrometry (ICP-OES). Results showed that, while Fe₂O₃ exerted a non-monotonic influence, Na₂O, MgO, and CaO improved apparent density and compressive strength, concurrently reducing water absorption, with these effects enhancing in a dose-dependent manner. Na₂O, MgO and Fe₂O₃ facilitated the formation of labradorite, cordierite and hematite, respectively. All fluxes weakened the diffraction peaks of quartz and mullite. ICP-OES results indicated that the fluxes slightly increased Pb and Zn leaching, yet the highest values (0.1975 mg/L for Pb, 0.0485 mg/L for Zn) were well below the limits specified in the Chinese national standard GB 5086.2-1997 (Leaching Toxicity of Solid Waste—Horizontal Vibration Extraction Procedure). This work shows optimized flux composition enables high-performance, eco-safe LZTs-CG ceramsite, supporting LZTs and CG high-value utilization and sustainable development. Full article

Microbial hydrocarbon degradation mediated by natural/modified clay minerals represents an eco-friendly and economically viable remediation strategy for hydrocarbon contamination. However, its effects are not always positive as they depend on multiple factors, including clay mineral types, modification methods, microbial species, and hydrocarbon substrates. This review systematically synthesizes existing fragmented studies concerning the impacts of natural clay minerals, modified clay minerals (acid/alkali/thermal/organic/metal ion), and clay minerals containing composite materials on microbial hydrocarbon biodegradation. Based on current findings, future research should prioritize the following recommendations: (1) avoid using concentrated strong acids in acid activation; (2) exclude metal cations that induce strong adsorption (reducing hydrocarbon bioavailability) or trigger excessive interlayer hydrolysis (some trivalent cations) in metal cation modification; (3) eliminate biologically toxic agents during organic modification; and (4) expand understanding of alkali/thermally modified clay minerals and clay mineral-containing composite materials in this direction. Natural/modified clay mineral-mediated microbial degradation is a highly promising remediation technology for hydrocarbon contamination and poised to advance and achieve breakthroughs through continuous synthesis of knowledge and innovation. Full article

The Zhunuo porphyry Cu deposit (2.9 Mt Cu @ 0.48%) in the Gangdese belt, southern Xizang, represents a key Miocene post-collisional system. This study integrates textural, major-, and trace-element analyses of pyrite from distinct alteration zones to unravel its hydrothermal evolution and metal precipitation mechanisms. Our study identifies four distinct pyrite types (Py1-Py4) that record sequential hydrothermal stages: main-stage Py2-Py3 formed at 354 ± 48 to 372 ± 43 °C (based on Se thermometry), corresponding to A and B vein formation, respectively, and late-stage Py4 crystallized at 231 ± 30 °C, coinciding with D-vein development. LA-ICP-MS data revealed pyrite contains diverse trace elements with concentrations mostly below 1000 ppm, showing distinct distribution patterns among different pyrite types (Py1-Py4). Elemental correlations revealed coupled behaviors (e.g., Au-As, Zn-Cd positive correlations; Mo-Sc negative correlation). Tellurium variability (7–82 ppm) records dynamic fO₂ fluctuations during system cooling. A comparative analysis of pyrite from the regional deposits (Xiongcun, Tiegelongnan, Bada, and Xiquheqiao) highlighted discriminative geochemical signatures: Zhunuo pyrite was enriched in Co-Bi-Ag-Pb (galena inclusions); Tiegelongnan exhibited the highest Cu but low Au-As; Xiquheqiao had the highest Au-As coupling; and Bada showed epithermal-type As enrichment. Partial Least Squares Discriminant Analysis (PLS-DA) identified Cu, As, and Bi as key discriminators for deposit types (VIP > 0.8), with post-collisional systems (Zhunuo and Xiquheqiao) showing intermediate Cu-Bi and elevated As versus arc-related deposits. This study establishes pyrite trace-element proxies (e.g., Se/Te, Co/Ni, and As-Bi-Pb) for reconstructing hydrothermal fluid evolution and proposes mineral-chemical indicators (Cu-As-Bi) to distinguish porphyry-epithermal systems in the Qinghai-Tibet Plateau. The results underscore pyrite’s utility in decoding metallogenic processes and exploration targeting in collisional settings. Full article

Coagulation–flocculation, historically reliant on simple inorganic salts, has evolved into a technically sophisticated process that is central to the removal of turbidity, suspended solids, organic matter, and an expanding array of micropollutants from complex wastewaters. This review synthesizes six decades of research, charting the transition from classical aluminum and iron salts to high-performance polymeric, biosourced, and hybrid coagulants, and examines their comparative efficiency across multiple performance indicators—turbidity removal (>95%), COD/BOD reduction (up to 90%), and heavy metal abatement (>90%). Emphasis is placed on recent innovations, including magnetic composites, bio–mineral hybrids, and functionalized nanostructures, which integrate multiple mechanisms—charge neutralization, sweep flocculation, polymer bridging, and targeted adsorption—within a single formulation. Beyond performance, the review highlights persistent scientific gaps: incomplete understanding of molecular-scale interactions between coagulants and emerging contaminants such as microplastics, per- and polyfluoroalkyl substances (PFAS), and engineered nanoparticles; limited real-time analysis of flocculation kinetics and floc structural evolution; and the absence of predictive, mechanistically grounded models linking influent chemistry, coagulant properties, and operational parameters. Addressing these knowledge gaps is essential for transitioning from empirical dosing strategies to fully optimized, data-driven control. The integration of advanced coagulation into modular treatment trains, coupled with IoT-enabled sensors, zeta potential monitoring, and AI-based control algorithms, offers the potential to create “Coagulation 4.0” systems—adaptive, efficient, and embedded within circular economy frameworks. In this paradigm, treatment objectives extend beyond regulatory compliance to include resource recovery from coagulation sludge (nutrients, rare metals, construction materials) and substantial reductions in chemical and energy footprints. By uniting advances in material science, process engineering, and real-time control, coagulation–flocculation can retain its central role in water treatment while redefining its contribution to sustainability. In the systems envisioned here, every floc becomes both a vehicle for contaminant removal and a functional carrier in the broader water–energy–resource nexus. Full article

Biofuels and value-added chemicals can be produced using biomass. These products can substitute the corresponding petroleum-based ones, reducing the carbon footprint, ensuring domestic production, and minimizing/exploiting organic wastes in a circular economy philosophy. Natural mineral-based catalysts seem to be a promising, eco-friendly, and low-cost approach for biomass valorization. This article attempts to highlight the potential of natural mineral-based catalysts for various processes targeting the above valorization. Natural zeolites and clays can be used as catalysts/CO₂ adsorbents and catalytic supports in various biorefinery processes (pyrolysis, gasification, hydrothermal liquefaction, esterification/transesterification, hydrotreatment, cracking, isomerization, oxidation, condensation, etc.). Acid/base, redox, and textural properties of these materials are key factors for their catalytic performance and can be easily regulated by suitable treatments, like calcination, acid/base-washing, metal impregnation, doping, etc., which are discussed in this article. The application of natural minerals in biorefinery processes makes them greener, cost-effective, and easily scalable. Full article

The persistent contamination of water bodies by organic compounds, heavy metals, and pathogenic microorganisms represents a critical environmental and public health concern worldwide. In this context, polymer composite materials have emerged as promising multifunctional platforms for advanced water purification. These materials combine the structural versatility of natural and synthetic polymers with the enhanced physicochemical functionalities of inorganic fillers, such as metal oxides and clay minerals. This review comprehensively analyzes recent developments in polymer composites designed to remove organic, inorganic, and biological pollutants from water systems. Emphasis is placed on key removal mechanisms, adsorption, ion exchange, photocatalysis, and antimicrobial action, alongside relevant synthesis strategies and material properties that influence performance, such as surface area, porosity, functional group availability, and mechanical stability. Representative studies are examined to illustrate contaminant-specific composite designs and removal efficiencies. Despite significant advancements, challenges remain regarding scalability, material regeneration, and the environmental safety of nanostructured components. Future perspectives highlight the potential of bio-based and stimuli-responsive polymers, hybrid systems, and AI-assisted material design in promoting sustainable, efficient, and targeted water purification technologies. Full article

Honey is a traditional remedy, with its biologically active compounds being responsible for its properties. The aim of this study was to characterize linden honey from a physico-chemical point of view as well as its antimicrobial and antibiofilm potential. Two samples of linden honey with different origins were subjected to physico-chemical analyses, including the determination of water content, impurities, dry matter, acidity, pH, reducing sugar content, total phenol content, flavonoids, antioxidant potency by DPPH, and mineral content. The microbiological analysis involved determining the inhibition rates of microbial growth and the antibiotic capacity of linden honey against ten standardized bacterial strains and five bacterial strains isolated from patients. The analyzed linden honey can be characterized based on physico-chemical parameters as having a slightly increased water content, moderate acidity, rich in antioxidants, and a balanced pH. The average concentrations of macroelements and microelements in the honey samples showed that potassium was the dominant mineral element, followed by calcium and magnesium. The heavy metal content was consistent with European and international standards. The chemical content of linden honey influenced its antimicrobial and antibiofilm potential. In Gram-positive bacteria, inhibition rates were between 70.83 and 91.28% (sample A) and 71.14–90.16% (sample B) when applying concentration c1. For Gram-negative bacteria, values ranged between 63.91 and 78.30% (sample A) and 46.56–90.92% (sample B) at concentration c1. In bacterial strains isolated from patients, the inhibition rate values were between 75.42 and 85.69% (sample A) and 78.31–86.22% (sample B) when applying concentration c1. The antimicrobial and antibiofilm potential was highlighted in all bacterial strains studied, with differences occurring depending on the concentration of honey tested and the type of bacterial strain studied. Full article

In this study, we investigate the recovery of Li and Co from spent LiCoO₂ cathodes of spent lithium batteries using a combined approach of mechanochemical activation (MA) and ammoniacal leaching. High-energy ball milling disrupts the layered structure of LiCoO₂, introduces defects, and increases surface area, which strongly improves subsequent dissolution. Leaching experiments in an ammonia–ammonium sulphate–sulphite medium were optimized by varying the solid-to-liquid ratio, sodium sulfite concentration, and temperature. Under the best conditions (90 °C, 120 min, S/L = 10 g/L, 0.5 M Na₂SO₃), nearly complete recoveries were obtained: 99.5% Li and 96.5% Co. Kinetic modeling based on the shrinking-core model confirmed that dissolution of both metals is controlled by chemical reaction, with activation energies of 45.7 kJ·mol⁻¹ for Li and 60.7 kJ·mol⁻¹ for Co. Structural and morphological analyses (XRD, SEM) supported the enhanced reactivity of the activated material. The study demonstrates that MA coupled with optimized ammoniacal leaching provides an efficient process for LiCoO₂ recycling, without using aggressive mineral acids and long treatment times. Full article

The isomerization of geraniol using natural, acid-modified minerals such as vermiculite presents a promising approach aligned with the principles of green chemistry. Vermiculite, a naturally abundant layered silicate mineral, was subjected to the acid activation and thoroughly characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). These methods allowed the evaluation of crystallinity, structural stability, and surface morphology, which are critical parameters in the heterogeneous catalysis. The catalytic performance of the modified vermiculite was examined in the transformation of geraniol under mild conditions. The study systematically investigated the influence of key process parameters—temperature, reaction time, and catalyst content—on the conversion of geraniol and products selectivities. Optimization using the response surface methodology (RSM), enabled the identification of conditions leading to high conversion of geraniol (up to 85%) and allowing us to obtain favorable selectivities toward linalool, thunbergol, and 6,11-dimethyl-2,6,10-dodecatrien-1-ol. The results indicate that the acid-treated vermiculite exhibits sufficient surface acidity to effectively catalyze isomerization and cyclization reactions, without requiring additional promoters or metal-based systems. Moreover, the use of RSM provided the efficient framework for optimization reaction conditions, reducing experimental workload, and enhancing process efficiency. This study demonstrates the viability of natural, low-cost minerals as environmentally friendly catalysts and supports their integration into sustainable and “green” chemical technologies. Full article

This article presents the manufacturing technology and mechanical properties of innovative pre-impregnated coatings (PCs). The base materials for PC are powders of metal oxides, non-metals, minerals and thermoplastic non-wovens. PC can be used in the manufacture of composites by methods such as vacuum infusion, autoclave curing or hand lamination. This is possible due to the novel PC structure consisting of a functional layer (FL) and a backing layer (BL). PCs are flexible so that they can be used on curved surfaces. In this work, five types of PC were subjected to a uniaxial tensile test. Depending on the powder used, failure force values ranging from 24.61 N to 28.73 N were obtained. In the next step, the pre-impregnated coatings were applied as a coating in “sandwich” composites made by vacuum infusion, which were subjected to three-point bending (3-PB) and adhesion tests. 3-PB tests proved that the coating remained integral with the substrate, even under high flexural deformation, while the adhesion achieved was in the range of 0.95 MPa to 1.57 MPa. PC can be used in many engineering products, e.g., for the coating of façade panels, roof tiles, automotive parts or rail vehicles, etc. Full article