Search Results (83)

Metal oxide nanomaterials have emerged as transformative materials in the quest to enhance the energy density and overall performance of lithium-ion batteries (LIBs) and solid-state batteries (SSBs). Their unique properties—including their large surface areas and short ion diffusion pathways—make them ideal for next-generation energy storage technologies. In LIBs, the high surface-to-volume ratio of metal oxide nanomaterials significantly enlarges the active interfacial area and shortens the lithium-ion diffusion paths, leading to an improved high-rate performance and enhanced energy density. Transition metal oxides (TMOs) such as nickel oxide (NiO), copper oxide (CuO), and zinc oxide (ZnO) have demonstrated significant theoretical capacities, while binary systems like NiCuO offer further improvements in cycling stability and energy output. Additionally, layered lithium-based TMOs, particularly those incorporating nickel, cobalt, and manganese, have shown remarkable promise in achieving high specific capacities and long-term stability. The synergistic integration of metal oxides with carbon-based nanostructures, such as carbon nanotubes (CNTs), enhances the electrical conductivity and structural durability further, leading to a superior electrochemical performance in LIBs. In SSBs, the use of oxide-based solid electrolytes like garnet-type Li₇La₃Zr₂O₁₂ (LLZO) and sulfide-based electrolytes has facilitated the development of high-energy-density systems with excellent ionic conductivity and chemical stability. However, challenges such as high interfacial resistance at the electrode–electrolyte interface persist. Strategies like the application of lithium niobate (LiNbO₃) coatings have been employed to enhance interfacial stability and maintain electrochemical integrity. Furthermore, two-dimensional (2D) metal oxide nanomaterials, owing to their high active surface areas and rapid ion transport, have demonstrated considerable potential to boost the performance of SSBs. Despite these advancements, several challenges remain. Morphological optimization of nanomaterials, improved interface engineering to reduce the interfacial resistance, and solutions to address dendrite formation and mechanical degradation are critical to achieving the full potential of these materials. Full article

The Qingshan lead–zinc (Pb–Zn) deposit in northwestern Guizhou Province is a structurally controlled, carbonate-hosted system formed from basin-derived hydrothermal processes. Geology, fluid inclusion, and isotopic data reveal a multi-stage hydrothermal circulation after Emeishan Large Igneous Province (ELIP, ~260 Ma) tectono-thermal reactivation within the Sichuan–Yunnan–Guizhu triangle (SYGT) area. Fluid inclusion microthermometry indicates that ore-forming fluids were derived from deep sources influenced by enhanced crustal heat flow linked with possible thermal input from Indo-Caledonian tectonic activity after ELIP. Ore-stage calcite records mixed carbon derived from marine carbonates with additional inputs from organic matter and deep-sourced fluids, reflecting carbonate dissolution and fluid–rock interaction. Sulfide, together with fluid inclusion temperatures > 120 °C, indicates sulfur derived from evaporitic sulfate reduced by thermochemical sulfate reduction (TSR); the heavy sulfur signature and partial isotopic disequilibrium among coexisting sulfides reflect dynamic fluid mixing during ore deposition. Lead isotopes indicate metallogenic metals were leached mainly from Devonian–Permian carbonates with subordinate basement input. Ore precipitated by cooling, depressurization, and mixing of metal-rich, H₂S-bearing fluids in structurally confined zones where the carbonate–clastic interface effectively trapped ore-forming fluids, producing high-grade sphalerite–galena mineralization. Collectively, these data support a Huize-type (HZT) carbonate-hosted Pb–Zn genetic model for the Qingshan deposit. Full article

The Wunuer deposit is an important hydrothermal Zn-Pb-Ag-Mo polymetallic deposit in the central Great Xing’an Range, NE China. The zinc–lead polymetal mineralization is closely hosted by the volcanic rocks of the Manketouebo formation (rhyolite and lithic crystal tuff) and related to the Mesozoic granite porphyry. Field evidence and petrographic observations have identified three mineralization stages within this deposit from deep to shallow: (1) late magmatic stage with vein-type Mo mineralization characteristics and mainly related to the deep granite porphyry; (2) magmatic–hydrothermal transition stage characterized by breccia-type Zn mineralization, which occurred within a steep cryptoexplosive breccia; and (3) hydrothermal stage featured by vein-type Zn-Pb-Ag mineralization hosted by the ore-bearing fractured zone. In this contribution, we present the mineralogy, zircon U-Pb age, sphalerite Rb-Sr dating, whole-rock geochemistry, and Hf-S-Pb isotopes of the Wunuer deposit. LA-ICP-MS zircon U-Pb dating of the ore-related granite porphyry, rhyolite, and lithic crystal tuff suggests that the Mo mineralization from the late magmatic stage occurred between 144.8 Ma and 145.8 Ma. The Rb-Sr isochron dating of sphalerite indicates that the hydrothermal stage Zn mineralization age is 121 ± 2.3 Ma, which is related to the volcanism of Baiyin’gaolao Formation in the Wunuer area. The concentrated and positive δ³⁴S_V-CDT values (0.17‰~5.40‰) of sulfides, as well as uniform Pb isotope compositions of granite porphyry intrusion and galena, jointly imply a magmatic source of metallogenic materials for Pb-Zn mineralization. Whole-rock geochemistry and Hf-Pb isotopes reveal that the granite porphyry and rhyolite both originated from a mantle-derived juvenile component and assimilated by minor ancient crustal material in an extensional setting. Our study demonstrates the prospect of further exploration for two mineralization events in the hydrothermal polymetallic deposits of the central Great Xing’an Range. Full article

It is well established that solar cells convert solar energy into electrical energy, thereby contributing to environmental sustainability by reducing dependence on fossil fuels. In the present study, thin films composed of different materials were employed with the aim of mitigating efficiency losses in polycrystalline solar cells, which operate at a specific output voltage of 0.5 V. To evaluate the performance of these films, solar irradiation tests were conducted in Ciudad Obregón, Sonora, Mexico, during periods that accounted for both seasonal and diurnal variations in solar irradiance. The experiments were carried out during peak solar hours, a time frame that represents the conditions of highest thermal stress and irradiance intensity and is therefore relevant for analyzing heat-related efficiency losses. The thin films investigated included silver nanoparticles, copper sulfide, potassium permanganate, zinc sulfide, and lead sulfide. An improvement of 0.5% in open circuit voltage gain was achieved, corresponding to a temperature difference of 13.5 °C between the hottest and coolest cells. Notably, the cells that exhibited efficiency enhancement were those incorporating silver nanoparticles and potassium permanganate, with varying deposition times in the chemical bath. Among these, the latter demonstrated superior performance (KMnO₄ performed best). So, the objective of this experimental work was to assess the effect of various thin film coatings on the performance of polycrystalline silicon solar cells under natural sunlight. Full article

The possibility of applying the complex hydrometallurgical approach, which includes stages of alkaline sulfide leaching (ASL) and ferric leaching, for copper and zinc extraction from substandard sulfide concentrates containing chalcopyrite, tennantite, sphalerite, and pyrite was studied. Ferric leaching was performed under different conditions (temperature, Fe³⁺ concentrations, pulp densities). It was shown that Cu and Zn extraction increased when temperature was increased from 50 to 90 °C, while increasing Fe³⁺ concentration from 5 to 20 g/L did not lead to an increase in metal extraction. Sulfide leaching pretreatment led to the destruction of tennantite and elimination of arsenic from the concentrates, which, in turn, allowed higher copper extraction to be achieved during the ferric leaching. Thus, it was shown that two-stage leaching including the stages of sulfide leaching and ferric leaching may be successfully used for copper and zinc extraction from substandard sulfide concentrates as sulfide leaching allows tennantite disruption and increased copper leaching. Thus, a novel combined approach based on known hydrometallurgical techniques was developed, and it may be used for the treatment of specific mineral raw materials (copper concentrates containing tennantite with high As and Zn contents). Full article

Although skarn-type deposits represent significant hosts for Co resources, the distribution patterns and enrichment mechanisms of associated Co resources within these deposits have not been systematically investigated. This study summarizes relevant data on Co resources from representative skarn-type deposits in China to comparatively reveal the grade and reserve characteristics, spatiotemporal distribution patterns, and coupled enrichment mechanisms of Co across three principal skarn mineralization subtypes: iron-, copper-, and lead–zinc polymetallic-dominated deposits. Studies demonstrate that Fe-dominated skarn-type cobalt deposits exhibit widespread distribution, high Co grades (100–2000 ppm), and abundant Co reserves (4000–32,000 t), demonstrating significantly superior Co resource potential compared to Cu-dominated (Co grades: 20–200 ppm, Co reserves: 3000–10,000 t) and Pb-Zn polymetallic-dominated (Co grades: 140–853 ppm, Co reserves: approximately 3000 t) subtypes. In these skarn-type cobalt deposits, cobalt is mainly hosted in sulfide minerals. Influenced by tectonic settings, magmatic activity, and hydrothermal fluid evolution, associated Co resources in these skarn-type deposits exhibit both regional zonation and stage-specific differential enrichment patterns. In the formation of skarn-type cobalt deposits, mantle-derived magmas play a critical role in the pre-enrichment of Co. The injection of mafic magmas, assimilation of evaporite sequences, and the dissolution–reprecipitation mechanism of hydrothermal fluids collectively promote the re-enrichment of Co during magmatic evolution. These findings provide a theoretical foundation for targeted exploration, sustainable development, and comprehensive utilization of associated Co resources in skarn-type deposits. Full article

Mining activity in Peru generates environmental liabilities with the potential to release toxic metals into the environment. This study conducted a comprehensive physical, chemical, mineralogical, and toxicological characterization of ten active and inactive tailings samples from the Arequipa region in southern Peru. Particle size distribution analysis, inductively coupled plasma atomic emission spectroscopy (ICP-AES), scanning electron microscopy with energy-dispersive spectroscopy (SEM-EDS), and the Toxicity Characteristic Leaching Procedure (TCLP) followed by ICP-MS were employed. The results revealed variable particle size distributions, with the sample of Secocha exhibiting the finest granulometry. Chemically, 8 out of 10 samples exhibited concentrations of at least two metals surpassing the Peruvian Environmental Quality Standards (EQS) for soils with values reaching >6000 mg/kg of arsenic (Paraiso), 193.1 mg/kg of mercury (Mollehuaca), and 2309 mg/kg of zinc (Paraiso). Mineralogical analysis revealed the presence of sulfides such as arsenopyrite, cinnabar, galena, and sphalerite, along with uraninite in the Otapara sample. In the TCLP tests, 5 out of 10 samples released at least two metals exceeding the environmental standards on water quality, with concentrations up to 0.401 mg/L for mercury (Paraiso), 0.590 mg/L for lead (Paraiso), and 9.286 mg/L for zinc (Kiowa Cobre). These results demonstrate elevated levels of Potentially Toxic Elements (PTEs) in both solid and dissolved states, reflecting a critical geochemical risk in the evaluated areas. Full article

This study demonstrated the successful recovery of zinc, lead, and copper collective concentrates from historical metal-bearing mine tailings (sulfide–polymetallic ore with a composition of 7.38% Zn, 1.45% Pb, and 0.49% Cu) using froth flotation techniques, which were originally developed during uranium ore mining. Froth flotation techniques were used to justify suitability for recovering metals. The effects of a dosage of the foaming agent Polyethylene glycol (PEG 600) at 50 and 100 g t⁻¹, collector types Aerophine 3418A (AERO), Danafloat 067 (DF), and potassium ethyl xanthate (KEX) at 50 and 80 g t⁻¹, and a suspension density of 300 and 500 g L⁻¹ on froth flotation collective concentrates were investigated. The final collective concentrate achieved recoveries exceeding 91% for lead (Pb), 88% for copper (Cu), and 87% for zinc (Zn). The obtained concentrates were analyzed using Atomic Absorption Spectroscopy (AAS) and X-ray Fluorescence Spectrometry (XRF), while selected samples were further examined via Scanning Electron Microscopy (SEM) with Energy Dispersive X-ray Spectroscopy (EDS). The resulting sulfide concentrates can subsequently be treated using suitable hydrometallurgical techniques. The application of these concentrates in metal production would help reduce the environmental burden of mining activities. Full article

Geometallurgy is an approach that utilizes predictive models that can support business decisions, mitigate risks, and enhance production efficiency. To develop an accurate geometallurgical model, it is essential to understand the behavior of each lithology within the ore body through geometallurgical testing. In this context, the present study aims to evaluate the performance of bench-scale tests conducted on the main mining fronts of a zinc mine operation located in Brazil. The mineral processing plant was designed to process lead and zinc sulfide ores without material stockpiling, where all ores extracted from the underground mine are immediately processed. The geometallurgical characterization was conducted through the following steps: sampling, crushing, grinding, and flotation. The recovery, concentrate, and tailing contents during the flotation stages of galena and sphalerite were analyzed. A mineralogical characterization using a Mineral Liberation Analyzer (MLA) was performed to assess the degree of particle liberation and mineral associations within the studied mining fronts. The results indicate that a higher degree of pyrite liberation leads to greater metallurgical recovery of mineralized bodies A (breccia-hosted orebody), B (sphalerite-rich doloarenite orebody), and C (upper replaced stratiform orebody). Among these, mineralized body C presents the highest recovery in the zinc and lead stages, with 99.5% and 86.2%, respectively. Full article

This paper presents an analysis of the current state of processing lead–zinc ores from the Koskudyk deposit (Kazakhstan). At present, polymetallic ores are being extracted from the Ridder-Sokolnoye, Zyryanovskoye, Maleevskoye, and Achisai deposits. However, the reserves of rich and easily beneficiable ores are being depleted, and the supply of raw materials from the developed deposits does not exceed 25 years. As a result, more complex and difficult-to-enrich oxidized and mixed ores are being involved in production, and the extraction of non-ferrous metals from these ores presents a significant technological challenge. The most effective method for enriching oxidized polymetallic ores is flotation with preliminary sulfidization. Laboratory studies were conducted on a sample of oxidized lead–zinc ore from the Koskudyk deposit, which contains 79.69% oxidized lead compounds and 84.72% oxidized zinc compounds. This study examines the effect of sulfidization using sodium sulfide and determines the oxidative–reductive potential (ORP) levels for various reagent dosages. The experiments demonstrated that a sodium sulfide dosage of 700 g/t at an ORP of −200 mV yields the most effective lead flotation, resulting in a lead recovery of 50.07%. Zinc recovery remained relatively unchanged across all tests, confirming the limited response of oxidized zinc minerals under the applied sulfidization conditions. The highest beneficiation efficiency was achieved within the ORP range of −160 to −200 mV, beyond which lead recovery began to decline. The findings underscore the importance of optimizing ORP to ensure the formation of a stable sulfide film on mineral surfaces and efficient collector attachment. These results provide practical guidance for improving flotation performance of oxidized ores and demonstrate the need for additional activation strategies in zinc recovery. Full article

In this article, the results of full-scale experiments on the addition of a sodium sulfide to the ${\mathrm{CaCO}}_3$ slurry circuit in a wet flue gas desulfurization (WFGD) plant are presented. Tests are performed on two comparable WFGD installations (spray tower, 4 spraying levels and two stage gypsum de-watering by hydrocyclones and vacuum belt filter) which allows the investigation of the influence of lignite composition (lignite mined in Poland and the Czech Republic are compared) on the reduction in mercury emission. Additionally, the efficiency of precipitation of metals from the slurry (Hg, Zn, Pb, Cd, Cr, Cu, Ni, Fe, Se, and Mn) is investigated as the result of sulfide addition. For both objects, mercury re-emission from absorber occurs (the concentration of mercury in the chimney is higher than that before the WFGD absorber) and the sulfide addition to WFGD slurry stops this phenomenon. The addition of sulfide works effectively (mercury removal efficiency from flue gas reaches up to 88% for Polish tests and up to 87% for Czech Republic tests). For the tests in the Poland power plant, all of measured metals are precipitated from the slurry (precipitation of metals efficiency varied from 2% for zinc to 88% for mercury), but in the case of the test in the power plant in the Czech Republic, there is no effect on manganese, iron, and lead (precipitation of metals efficiency varied from 6.5% for copper to 86% for mercury). The addition of sulfide works effectively for lignite mined in Polish and Czech power plants under the conditions of similar WFGD installations. Full article

Copper zinc tin sulfide (commonly known as CZTS) solar cells (SCs) are gaining attention as a promising technology for sustainable electricity generation owing to their cost-effectiveness, availability of materials, and environmental advantages. The goal of this study is to enhance CZTS SC performance by adding a back surface field (BSF) layer. SC capacitance simulator software (SCAPS) was used to examine three different configurations. Another option is to replace the cadmium sulfide (CdS) buffer layer with a titanium dioxide (TiO₂) layer. The results demonstrate that the reduced graphene oxide (rGO) BSF layer increases the conversion efficiency by 25.68% and significantly improves the fill factor, attributed to lowering carrier recombination and creating a quasi-ohmic contact at the interface between the metal and semiconductor. Furthermore, replacing the CdS buffer layer with TiO₂ offers potential efficiency gains and mitigates environmental concerns associated with the toxicity of CdS. The results of this investigation could enhance the efficiency and viability of CZTS SCs for future energy applications. However, it is observed that BSF layers may become less effective at elevated temperatures due to increased recombination, leading to reduced carrier lifetime. This study underlines valuable insights into optimizing CZTS SC performance through advanced material choices, highlighting the dual benefits of improved efficiency and reduced environmental impact. Full article

Metal-mining activities inevitably generate contaminants in high quantities, which can pose a risk to soil, water, biota, and humans. This study compares the geochemical properties of waste materials of tailings and waste rock heaps originating from the same high-sulfidation-type epithermal mineralization. Field sampling was conducted in the Recsk Copper Mining Area on the H2 tailings and H7 waste heap, where a total of 48 samples were collected at various depths. The results showed that PTEs were present in varying concentrations and behaved differently in the two waste materials. Copper concentrations were approximately five times higher in H2 tailings (median 1660 mg/kg) than in H7 waste rock (median 347 mg/kg), whereas arsenic was 2.8 times more concentrated in H2 tailings (674 mg/kg vs. 238 mg/kg). Conversely, zinc (114 mg/kg vs. 24 mg/kg), lead (172 mg/kg vs. 42.8 mg/kg), and cadmium (0.83 mg/kg vs. 0.097 mg/kg) show significantly higher concentrations in H7 waste rock. Element mobility analyses revealed that calcium mobility in H7 waste rock (65%) was twice that observed in H2 tailings (32%), with copper showing a threefold higher mobility in H7 despite lower total concentrations. NAG pH values (2.06–3.23) confirmed significant acid-generating potential in both waste types, with the H7 waste rock posing greater immediate environmental risk due to higher element mobility and more advanced weathering indicated by elevated jarosite (4.05%–8.01%) and secondary mineral contents. These findings demonstrate that, despite originating from the same mineralization, the distinct processing histories and physical properties of these materials necessitate unique approaches for successful remediation or secondary raw material extraction. Full article

A slurry’s rheological properties significantly affect flotation performance. Flotation variables—including mineral composition, slurry concentration, and ore particle size—influence these properties by altering the interaction forces between mineral particles and the slurry’s microstructure, thereby impacting flotation outcomes. This study investigated the effects of flotation variables on the rheological properties and flotation performance of lead–zinc sulfide ores in two ternary systems comprising galena or sphalerite + kaolinite and quartz. Cryo-scanning electron microscopy and atomic force microscopy were used to analyze the slurries’ interaction forces and microstructure. The results show that finer ore particle sizes increase the formation of particle agglomerates, leading to larger structures and higher slurry apparent viscosity. This improves the metal mineral recovery rate during flotation but simultaneously increases gangue mineral entrainment, reducing concentrate grade. As the slurry concentration increases, the ternary system with kaolinite as the main gangue mineral forms a denser and more rigid honeycomb network structure. This results in higher yield stress and apparent viscosity, which negatively impacts lead and zinc sulfide separation during flotation. In contrast, the quartz-dominated system forms a slightly denser, stacked structure that lacks a solid network and thus maintains lower yield stress and apparent viscosity, which favors mineral separation. Adding sodium hexametaphosphate enhances particle dispersion by increasing repulsive forces between mineral particles. This thins or disrupts the kaolinite network structure, reducing the slurry’s apparent viscosity and yield stress, thereby improving its rheological properties and facilitating the flotation separation of lead and zinc sulfide minerals. Full article