Search

• Using the GRA-BILSTM prediction model in NEV battery recycling studies. • Studied the impact of different battery market shares on metal supply and demand. • Retired batteries have great potential for secondary use and material recovery. • Assessed the impact of metal recycling on the supply of key metals. • Assessing Key Metal Supply Risks Against Chinese and World Reserves. As Chinese new energy vehicle (NEV) sales continue to grow, end-of-life batteries have great potential for recycling in the future. In this study, a combined model based on Gray Relation Analysis and Bi-directional Long Short-Term Memory (GRA-BiLSTM) is proposed for predicting NEV sales, and the NEV battery life is modeled using the Weibull distribution. Then, the amount of end-of-life batteries, secondary utilization and metal recycling are calculated. The impact of end-of-life battery recycling on the supply and demand of key metals is studied. The results show that in 2040, the secondary utilization of end-of-life batteries in the Standard Growth Rate-Lithium Iron Phosphate Battery Dominated-High Secondary Utilization rate scenario (SGR-LFP H) is 391.76 GWh. The recycling volumes of lithium, nickel and cobalt are 45,900 tons, 92,900 tons and 22,100 tons, respectively. In the Standard Growth Rate-lithium nickel cobalt manganese oxide Battery Dominated-Low Secondary Utilization rate scenario (SGR-NCM L), the recycling of lithium, nickel and cobalt is even greater, at 62,600 tons, 372,200 tons and 71,700 tons, respectively. End-of-life batteries recycling can reduce the demand for metals. However, as NEV sales continue to grow, the gap between metal supply and demand remains significant. The findings urge the Chinese government develop appropriate battery management strategies to increase the recycling rate of end-of-life batteries; and to encourage enterprises to research new types of batteries to resolve the conflict between supply and demand for metals. [ABSTRACT FROM AUTHOR]

• Case study feasibility of real-time computer vision-based scrap metal separation. • Analysis of neural network architectures for recognition of forbidden scrap. • Proposal of a neural classifier analyzing a non-standardized stream of metal scrap. • Dataset augmentation for improved model robustness of a neural classifier. • Eliminating human in the detection of prohibited objects in copper-based scrap. Highly efficient industrial sorting lines require fast and reliable classification methods. Various types of sensors are used to measure the features of an object to determine which output class it belongs to. One technique involves the use of an RGB camera and a machine learning classifier. The paper is focused on protecting the sorting process against prohibited and dangerous items potentially present in the sorted material that pose a threat to the sorting process or the subsequent metallurgical process. To achieve this, a convolutional neural network classifier was applied under real-life conditions to detect forbidden elements in copper-based metal scrap. A laboratory stand simulating the working conditions in a high-speed scrap sorting line was prepared. Using this custom stand, training and test sets for machine learning were gathered and labeled. An image preprocessing algorithm was designed to increase the robustness of the resulting forbidden element detector system. The performance of multiple neural network architectures and data set augmentations was analyzed. The highest accuracy of 98.03% and F1-score of 97.16% were achieved with a DenseNet-based classifier. The results of this paper show the feasibility of using the presented solution on a high-speed industrial line. [ABSTRACT FROM AUTHOR]

Rhodium and iridium, both belonging to the platinum group metals, are critical metals due to their scarcity and broad industrial applications, particularly in automotive catalysts. With increasing global demand for PGMs and the depletion of primary resources, recycling spent catalysts has become essential for sustainable resource management and reducing environmental impact. This review focuses on recent advancements in the dissolution of Rh and Ir from spent catalysts, highlighting various hydrometallurgical leaching methods. Aqua regia, while commonly used, shows limited efficiency for both Rh and Ir due to their chemical inertness. More advanced techniques such as HCl-based systems with oxidizing agents like NaClO or NaClO3, microwave-assisted leaching, and dry aqua regia have demonstrated improved dissolution efficiency. There is some difference in the dissolution behavior between Rh and Ir metal by the reported leaching systems. Owing to the stronger chemical inertness of iridium metal, its dissolution requires different approaches from the dissolution of Rh. Microwave-assisted leaching offers superior Rh recovery rates, while Ir dissolution benefits from dry aqua regia, which reduces energy consumption by generating chlorine in situ at lower temperatures. Additionally, alloy fragmentation has proven effective for Ir dissolution by increasing surface area and enhancing chemical reactivity. The environmental and operational advantages of dry aqua regia are highlighted, presenting them as viable options for industrial recycling. This review would contribute to the development of sustainable processes for the recovery of these critical metals from secondary resources. [ABSTRACT FROM AUTHOR]

The growing demand for ferrous metals and abundant scrap materials has fueled Nigeria’s scrap-iron smelting industry, leading to hazardous pollutant emissions. This study investigated the concentrations, seasonal and indoor-outdoor variations, origins, and health impacts of polycyclic aromatic hydrocarbons (PAHs) in dust samples around a scrap-iron smelting facility. Analyses of dust samples revealed that high molecular weight PAHs (HMWPAHs) dominated during both seasons, with 5-ring PAHs (34%) contributing most during the rainy season and 3-ring PAHs (36%) during the dry season. Carcinogenic PAHs were more prevalent in the rainy season compared to the dry season. Seven PAH sources were identified, with gasoline combustion being the dominant source during the rainy season and iron and steel production during the dry season. Incremental lifetime cancer risk (ILCR) assessments showed PAH concentrations within safe limits, with dermal contact identified as the primary exposure pathway for both children and adults in the study area. [ABSTRACT FROM AUTHOR]

Purpose: Magnetic polarizability tensors (MPTs) provide an economical characterisation of conducting magnetic metallic objects and their spectral signature can aid in the solution of metal detection inverse problems, such as scrap metal sorting, searching for unexploded ordnance in areas of former conflict and security screening at event venues and transport hubs. In this work, the authors aim to discuss methods for efficiently building large dictionaries for classification approaches. Design/methodology/approach: Previous work has established explicit formulae for MPT coefficients, underpinned by a rigorous mathematical theory. To assist with the efficient computation of MPTs at differing parameters and objects of interest, this work applies new observations about the way the MPT coefficients can be computed. Furthermore, the authors discuss discretisation strategies for hp-finite elements on meshes of unstructured tetrahedra combined with prismatic boundary layer elements for resolving thin skin depths and using an adaptive proper orthogonal decomposition (POD) reduced-order modelling methodology to accelerate computations for varying parameters. Findings: The success of the proposed methodologies is demonstrated using a series of examples. A significant reduction in computational effort is observed across all examples. The authors identify and recommend a simple discretisation strategy and improved accuracy is obtained using adaptive POD. Originality/value: The authors present novel computations, timings and error certificates of MPT characterisations of realistic objects made of magnetic materials. A novel postprocessing implementation is introduced and an adaptive POD algorithm is demonstrated. [ABSTRACT FROM AUTHOR]

Background: This study reports the preparation of 2‐hydroxy‐3‐(4‐(((2‐((2‐(((E)‐4‐(2‐hydroxy‐3‐(trimethylammonio)propoxy)‐3‐methoxybenzylidene)amino)ethyl)amino)ethyl)imino)methyl)‐2‐methoxyphenoxy)‐N,N,N‐trimethylpropan‐1‐aminium (HYM/QA). The adsorbent was employed to extract and concentrate vanadium from its solutions and boiler ash samples. Results: The impact of initial dosage, pH, reaction time and temperature on the sorption behavior of V(V) was examined. Under optimal conditions (pH 5, 0.08 g dose, 45 min at room temperature), a sorption capacity of 392.25 mg g−1 was achieved. The uptake of V(V) on HYM/QA was effectively reversed using 1 mol L−1 NaOH, regenerating the material. After six cycles of sorption and elution, the sorption capability remained at 91.4% of its initial value. The efficiency and selectivity of HYM/QA toward V5+ ions were assessed using the separation factor parameter, revealing limited interference from heavy metals such as Mn2+, Cr3+, Pb2+, Si4+, Al3+, NO32−, HCO3− and Zn2+. The uptake process of HYM/QA for V(V) conformed to the Langmuir and Dubinin–Radushkevich isotherm models and the pseudo‐second‐order kinetic model. HYM/QA was characterized by infrared, Brunauer–Emmett–Teller surface area, 1H NMR, 13C NMR and gas chromatography–mass spectrometry analyses, confirming successful preparation. Thermodynamic assessments suggested that the sorption process is endothermic, spontaneous and becoming more favorable with rising temperature. Conclusion: The optimized conditions were used to adsorb vanadium from boiler ash samples, and the obtained vanadium pentaoxide was analyzed and confirmed using various tools, demonstrating the material's effectiveness for vanadium extraction. © 2024 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

Seabed unexploded ordnance that resulted partly from the high failure rate among munitions from more than 80 years ago and from decades of military training and testing of weapons systems poses an increasing concern all around the world. Although existing magnetic systems can detect clusters of debris, they are not able to tell whether a munition is still intact requiring special removal (e.g. in situ detonation) or is harmless scrap metal. The marine environment poses unique challenges, and transferring knowledge and approaches from land to a marine environment has not been easy and straightforward. On land, the background soil conductivity is much lower than the conductivity of the unexploded ordnance and the electromagnetic response of a target is essentially the same as that in free space. For those frequencies required for target characterization in the marine environment, the seawater response must be accounted for and removed from the measurements. The system developed for this study uses fields from three orthogonal transmitters to illuminate the target and four three‐component receivers to measure the signal arranged in a configuration that inherently cancels the system's response due to the enclosing seawater, the sea–bottom interface and the air–sea interface for shallow deployments. The system was tested as a cued system on land and underwater in San Francisco Bay – it was mounted on a simple platform on top of a support structure that extended 1 m below and allowed the diver to place metal objects to a specific location even in low‐visibility conditions. The measurements were stable and repeatable. Furthermore, target responses estimated from marine measurements matched those from land acquisition, confirming that the seawater and air–sea interface responses were removed successfully. Thirty‐six channels of normalized induction responses were used for the classification, which was done by estimating the target principal dipole polarizabilities. Our results demonstrated that the system can resolve the intrinsic polarizabilities of the target, with clear distinctions between those of symmetric intact unexploded ordnance and irregular scrap metal. The prototype system was able to classify an object based on its size, shape and metal content and correctly estimate its location and orientation. [ABSTRACT FROM AUTHOR]

Efficient catalyst design has garnered significant interest in recent decades due to its potential to address both the challenges of the greenhouse effect and energy shortages by facilitating the conversion of CO2 into valuable chemicals through catalytic reactions. To investigate maximizing the synergistic effects of supported PdAu catalysts, we conducted first-principles calculations on the activation and decomposition of CO2 and H2 on the PdAu/In2O3(110) system. The results demonstrate that the incorporation of a secondary metal (Au) into the supported Pd catalyst, in conjunction with precise control over Au concentration, exerts influence on both reactant binding energy and activation. The adsorption and activation of CO2 at the interface sites of Au4/In2O3(110) and PdAu3/In2O3(110) are not observed. The transition state for the dissociation of CO2 into *CO and *O is determined based on adsorbed CO2, providing insights into the properties of activated CO2. The Bronsted–Evans–Polanyi relation, which correlates activation barriers (Ea) with reaction energies (Er), was established for the CO2 dissociation mechanism on PdAu/In2O3(110) catalysts using equation E = 0.4Ea + 0.63. It was carried out to investigate the H2-dissociated adsorption processes and mobility energy on various PdAu/In2O3(110) catalysts. Finally, a highly efficient Pd2Au2/In2O3 catalyst for the hydrogenation of CO2 into methanol has been proposed. This research provides valuable insights into the hydrogenation of CO2 to methanol using bimetal-oxide catalysts and contributes to the optimization of the design of PdAu/In2O3 catalysts for CO2 reactions. [ABSTRACT FROM AUTHOR]

Compared with fossil-dependent process, glycerol hydrogenolysis to 1,2-propanediol (1,2-PDO) is a green sustainable route with much advantage. The commercial scale of this reaction has been achieved, and catalysts with high efficiency are continuously developed. Cu-based catalysts are considered as the most selective catalysts for 1,2-PDO production, which are widely investigated up to now. Understanding the structure-activity relationship can help the design of new catalytic materials with improved activity, selectivity and stability. In this review, the roles of various active structures on Cu catalysts are summarized. We introduce firstly the pioneering works, showing that Cu species are the primary active sites which can catalyze both the glycerol dehydration and C = O bond hydrogenation steps. Then, we summarize various viewpoints about the structure-sensitive effect of Cu in the reaction. The functions of support and promoter are subsequently discussed in detail, and the roles of the secondary metal site are further overviewed. After that, we propose critical factors that should be considered when investigating the Cu structure sensitive effect, and summarize three general roles of support, promoter and secondary metal. Further important research directions for Cu catalysts in glycerol hydrogenolysis are also outlined. [ABSTRACT FROM AUTHOR]

The stirring energy of bottom blowing is one of the most important factors affecting the steel scrap melting in converter. In this paper, a three-dimensional turbulent-multiphase-solidification/melting-solute transport coupling mathematical model is developed to investigate the molten metal flow and scrap melting behaviors in a steelmaking converter under asymmetric bottom blowing conditions. The mathematical model is verified by hot-state experiments. The results show that the dead zone volume fraction and mixing time can be reduced by 3 pct and 30 second by asymmetric bottom blowing, which can provide greater stirring kinetic energy for the molten bath, especially at the bottom of the molten bath, thereby accelerating the melting rate of the steel scrap. In Scheme A1, the time required for the complete melting of the steel scrap is 434 second, which is reduced by 96 second compared with the scheme of symmetrical blowing. Asymmetric bottom blowing can promote the heat exchange between low-temperature molten metal around steel scrap and high-temperature melt in other regions, so that the temperature field around steel scrap is stable at about 1710 K. Meanwhile, it can effectively promote the diffusion of carbon in steel scrap and then promote the rapid melting of scrap. [ABSTRACT FROM AUTHOR]

In this paper, we investigate the ejection production from twice-shocked Sn using molecular dynamic simulations in regimes where the metal undergoes complete shock melting after the first shock. A new description form of a bubble shape is proposed to fit the interface during the whole stage, which overcomes the inapplicability of the flycut profile in later stages. We then explore the ejection on second shock with the dimensionless intervals of ∼3.8 and ∼96 between the two shocks. Surprisingly, the results show that the ejecta model can well predict the second ejecta mass with a shock interval of ∼3.8 while far underestimated that with a shock interval of ∼96. We find that in the presence of the first ejecta, the high-speed secondary interface interacts with the low-speed first ejecta, resulting in the movement of liquid metals to the secondary ejecta, thereby promoting the increase of secondary ejecta mass. These findings are further validated by our smoothed particle hydrodynamics simulations at a macroscale. [ABSTRACT FROM AUTHOR]

Copyright of Umsatzsteuer-Rundschau is the property of De Gruyter and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This mini‐review comprehensively outlines the latest advancements in protecting zinc anodes in zinc‐ion batteries (ZIBs) through chelation mechanisms. Chelation involves the coordination of ligands with Zn2+, offering promising strategies to address challenges such as dendrite formation and hydrogen evolution reactions. However, there is a lack of comprehensive and unified evaluation of chelation's protective effect on the zinc anode, which hinders a thorough assessment of chelation's effectiveness. Recent studies have demonstrated the excellent protective performance of chelation in altering solvation structures, modifying SEI structures, and selectively adsorbing species on the zinc anode. Furthermore, while chelation demonstrates significant benefits for the zinc anode, its impact on cathode materials must also be considered. Proper selection of chelation strengths and compatible cathode materials is essential for overall battery performance. Future research directions include exploring the effects of different ligands and coordination numbers on battery performance and extending chelation strategies to other secondary metal batteries. Understanding and optimizing chelation mechanisms are critical for advancing the development of high‐performance ZIBs and other metal‐ion battery technologies. [ABSTRACT FROM AUTHOR]

Incorporating electrocatalytic active sites into the reticular framework allows for the design of novel catalytic structures promoting desired catalytic reactions with efficient mass transfer. However, to fully exploit the advantages of such a framework, it is crucial to ensure the electrochemical stability of the material. In this context, alkaline‐stable bimetallic MxNi2‐xCl2BTDD (M = Fe, Co) metal–organic frameworks (MOFs) are employed as electrocatalysts for alkaline water oxidation reaction (WOR) to understand the correlation between secondary metal incorporation and catalytic activity changes. For a specific Fe ratio within the MOF, the optimal catalytic activity is achieved at an overpotential of 315 mV at a WOR current density of 10 mA cm−2geo. Based on its well‐defined crystal structure and uniformly arranged metal nodes, which are not limited to specific facets, the cooperative electrocatalytic mechanism during the faradaic WOR process is investigated through operando Raman spectroscopy and density functional theory calculations. These results enable the interpretation of the electrochemical WOR mechanism based on MOF, providing a further fundamental understanding of electrocatalytic activity in bimetallic systems. [ABSTRACT FROM AUTHOR]

It is widely established that the electroreduction of carbon dioxide on a copper surface yields a spectrum of alcohols and hydrocarbons. But the selectivity of Cu toward a certain product is extremely poor as it forms a variety of reduced products concurrently. Controlling selectivity and overall performance depends on the modification of the Cu site and local environment. This study depicts how the product selectivity can be switched from C1 to C2 and multicarbon products by systematic incorporation of secondary metal (Pd) into the Cu lattice. Upon releasing the structural ordering from intermetallic to alloy and then to bimetallic, a systematic enhancement on the formation of C2 products from CO2 has been observed. Real‐time in situ X‐ray absorption spectroscopy (XAS) study showed the potential dependent evolution of Pd─Cu and Cu─Cu bonds in different Pd‐Cu‐based catalysts. The detailed analysis of in situ IR and Raman also determined the adsorbed intermediate species and helped to identify the mechanism. Computational studies show the feasibility of multicarbon product formation on bimetallic catalysts compared to alloy and intermetallic catalysts. The current density and the activity of the CO2 electroreduction have been enhanced by the utilization of the flow cell in the gas diffusion electrode configuration. [ABSTRACT FROM AUTHOR]

The presence of sulfur compounds in the chemical industry poses significant environmental and economic problems, including endangering human and animal lives and damaging equipment. For this purpose, hierarchical HY zeolite (Hie‐Y) with a SiO2/Al2O3 molar ratio 10 was successfully synthesized through sequential desilication‐dealumination using NH4OH treatment. A weak alkaline media with surfactant cetyltrimethylammonium bromide (CTAB) facilitates mesoporosity formation and preserves the zeolite structure. Metal oxide (CuO, MoO3) ‐ hierarchical HY zeolite nanocomposites have been prepared by one or a combination of 3 methods: 1) ion exchange, 2) precipitation, and 3) calcination. The obtained catalysts were characterized using XRD, FT‐IR, FESEM, UV‐Vis, EDS, and BET techniques. The formation of a hierarchical structure is associated with structure preservation, but partial destruction occurs based on the entering Cu in the zeolite pores. These catalysts have been studied in the oxidative desulfurization (ODS) reaction. Several parameters, including temperature, catalyst amount, DBT concentration, and reaction time, were evaluated in ODS using the Taguchi Design of Experiments. Catalytic activity order was obtained as Y

Magnetic solid-phase extraction (MSPE) is a highly effective method for separating metal ions from aquatic solutions, making it a popular choice for metal ion separation. This study investigated the behavior of Fe3O4@SiO2-SH core–shell composites for the adsorption and recovery of silver ions. The quality of the synthesized adsorbent was verified using XRD, FT-IR, EDS, FE-SEM, and EDAX-map analyses. Magnetic properties and surface charge changes were assessed using VSM and Zeta potential analyses. By implementing the classic OFAT method, the study evaluated the effect of various parameters on silver adsorption, such as pH, composite dosage, initial Ag+ concentration, temperature, and secondary metal ions. Results showed that the proposed composite had a high maximum adsorption capacity (112 mg/g) at pH = 6, ambient temperature, 0.1 g/L adsorbent dosage, and silver concentrations greater than 25 mg/L. The composite demonstrated good selectivity in Ag+ separation from a bimetallic solution containing silver and mercury ions. The results also showed that 1M HNO3 and 1M HCl solutions released over 78% and 70% of absorbed ions from the composite surface, respectively. However, the HCl solution enabled the precipitation of almost all desorbed Ag+, providing a selective recovery of silver ions. [ABSTRACT FROM AUTHOR]

Lithium metal is a possible anode material for building high energy density secondary batteries, but its problems during cycling have hindered the commercialization of lithium metal secondary batteries. Until now, many sophisticated techniques have been used to obtain rich micro‐morphological and physicochemical information of the deposition layer and the solid electrolyte interface (SEI), and to develop improvement strategies based on the information and achieve remarkable results. Regulating the reaction process around key links is a classic strategy to achieve expected results. Based on this empirical fact, we artificially highlighted the differences in the apparent performance of lithium metal anode using different series of electrolytes. We used microelectrode technology to analyze the reaction mechanisms and kinetic characteristics of each elementary step under all electrolyte conditions, revealing common laws that affect apparent performance and the basic steps that have a decisive impact on apparent performance. We discussed and elucidated the relevant physical and chemical principles, providing a clear basis for improving the pertinence and efficiency of improvement strategies. [ABSTRACT FROM AUTHOR]

The development of cost-effective and high-performance non-noble metal catalysts for the oxygen reduction reaction (ORR) holds substantial promise for real-world applications. Introducing a secondary metal to design bimetallic sites enables effective modulation of a metal-nitrogen-carbon (M-N-C) catalyst's electronic structure, providing new opportunities for enhancing ORR activity and stability. Here, we successfully synthesized an innovative hierarchical porous carbon material with dual sites of Zn and Mg (Zn/Mg-N-C) using polymeric ionic liquids (PILs) as precursors and SBA-15 as a template through a bottom-up approach. The hierarchical porous structure and optimized Zn-Mg bimetallic catalytic centers enable Zn/Mg-N-C to exhibit a half-wave potential of 0.89 V, excellent stability, and good methanol tolerance in 0.1 M KOH solution. Theoretical calculations indicated that the Zn-Mg bimetallic sites in Zn/Mg-N-C effectively lowered the ORR energy barrier. Furthermore, the Zn-air batteries assembled based on Zn/Mg-N-C demonstrated an outstanding peak power density (298.7 mW cm-2) and superior cycling stability. This work provides a method for designing and synthesizing bimetallic site catalysts for advanced catalysis. [ABSTRACT FROM AUTHOR]

The catalytic partial oxidation of methane (POM) presents a promising technology for synthesizing syngas. However, it faces severe over-oxidation over catalyst surface. Attempts to modify metal surfaces by incorporating a secondary metal towards C–H bond activation of CH4 with moderate O* adsorption have remained the subject of intense research yet challenging. Herein, we report that high catalytic performance for POM can be achieved by the regulation of O* occupation in the atomically dispersed (AD) MoNi alloy, with over 95% CH4 conversion and 97% syngas selectivity at 800 °C. The combination of ex-situ/in-situ characterizations, kinetic analysis and DFT (density functional theory) calculations reveal that Mo-Ni dual sites in AD MoNi alloy afford the declined O2 poisoning on Ni sites with rarely weaken CH4 activation for partial oxidation pathway following the combustion reforming reaction (CRR) mechanism. These results underscore the effectiveness of CH4 turnovers by the design of atomically dispersed alloys with tunable O* adsorption. The catalytic partial oxidation of methane (POM) is a promising technology for synthesizing syngas but suffers from severe over-oxidation on the catalyst surface. Here the authors demonstrate that regulating O* occupation in an atomically dispersed MoNi alloy can achieve high catalytic performance for POM. [ABSTRACT FROM AUTHOR]

Purpose: The mining industry plays a critical role in the global economy by providing raw materials and metals for various sectors, but it is also associated with environmental and social impacts. This paper presents a comparison of the findings from social life cycle assessment (S-LCA) with those obtained from a stakeholders' risk perception analysis. The goal is to provide a multifaceted view on the challenges faced by the mining industry in achieving sustainable practices. Methods: This research reports the results of S-LCA and stakeholders' risk perception analysis used to evaluate the social dimension of sustainability in two different European Horizon 2020 projects: (i) recovery of secondary metals and minerals from mining residues through bioleaching and chemical precipitation (project NEMO with a demonstration site in Finland), and (ii) recycling of wastewater and valorization of tailings from mining activities to create geopolymers through chemical activation (project ITERAMS with a demonstration site in Portugal). Results: The S-LCA conducted in NEMO reveals that fair salary is the social category presenting the highest risk (22% of the total). This risk is unequally shared between foreground activities (4%) and background activities (18%), and it occurs mostly in Finland. The S-LCA in ITERAMS shows that the low percentage of employees organized in trade unions accounts for the highest social risk (14%), occurring mostly with the background activities (8.5% out of the 14%). The risk perception analysis conducted among involved stakeholders for both projects highlighted that the analysis performed using only S-LCA databases overestimated some social issues (e.g., access to biomass, trade unionism) that were not relevant for local stakeholders while underestimating, or even ignoring, other social issues that are considered important by the same stakeholders (e.g., health and safety, housing prices). Conclusions: The two case studies show the critical need to integrate locally gathered data from stakeholders directly involved in the projects with the broader insights offered by sector-level S-LCA. Local analysis can capture site-specific dynamics and social risk perceptions, while S-LCA can extend the analysis to the entire supply chain. Both analyses highlighted that one of the main limitations of the current S-LCA framework is the omission of the positive environmental, social and economic effects resulting from the proposed projects. Ultimately, these case studies provided valuable insights for the stakeholders involved in both projects, facilitating information sharing concerning the primary social risks associated with the development and implementation of the technologies proposed by the projects. This empowers decision-makers with the information required to formulate strategies that can enhance the sustainability of the bioleaching and geopolymer technologies used to valorize mining residues. [ABSTRACT FROM AUTHOR]

This review article addresses the increasing environmental concerns posed by synthetic dyes in water, exploring innovative approaches for their removal with a focus on zero-valent iron nanoparticles (nZVIs) synthesized through environmentally friendly methods. The article begins by highlighting the persistent nature of synthetic dyes and the limitations of conventional degradation processes. The role of nanoparticles in environmental applications is then discussed, covering diverse methods for metallic nanoparticle production aligned with green chemistry principles. Various methods, including the incorporation of secondary metals, surface coating, emulsification, fixed support, encapsulation, and electrostatic stabilization, are detailed in relation to the stabilization of nZVIs. A novel aspect is introduced in the use of plant extract or biomimetic approaches for chemical reduction during nZVI synthesis. The review investigates the specific challenges posed by dye pollution in wastewater from industrial sources, particularly in the context of garment coloring. Current approaches for dye removal in aqueous environments are discussed, with an emphasis on the effectiveness of green-synthesized nZVIs. The article concludes by offering insights into future perspectives and challenges in the field. The intricate landscape of environmentally friendly nZVI synthesis has been presented, showcasing its potential as a sustainable solution for addressing dye pollution in water. [ABSTRACT FROM AUTHOR]

Electrochemical acetylene reduction (EAR) employing Cu catalysts represents an environmentally friendly and cost‐effective method for ethylene production and purification. However, Cu‐based catalysts encounter product selectivity issues stemming from carbon‐carbon coupling and other side reactions. We explored the use of secondary metals to modify Cu‐based catalysts and identified Cd decoration as particular effective. Cd decoration demonstrated a high ethylene Faradaic efficiency (FE) of 98.38 % with well‐inhibited carbon‐carbon coupling reactions (0.06 % for butadiene FE at −0.5 V versus reversible hydrogen electrode) in a 5 vol % acetylene gas feed. Notably, ethylene selectivity of 99.99 % was achieved in the crude ethylene feed during prolonged stability tests. Theoretical calculations revealed that Cd metal accelerates the water dissociation on neighboring Cu surfaces allowing more H* to participate in the acetylene semi‐hydrogenation, while increasing the energy barrier for carbon‐carbon coupling, thereby contributing to a high ethylene semi‐hydrogenation efficiency and significant inhibition of carbon‐carbon coupling. This study provides a paradigm for a deeper understanding of secondary metals in regulating the product selectivity of EAR electrocatalysts. [ABSTRACT FROM AUTHOR]

The oxidation of carbon in conventional gas diffusion electrodes is a limiting factor for the life of secondary metal-air batteries. Replacement of carbon with zeolite is a possible solution to avoid its oxidation in the gas-diffusion electrodes (GDE) and thus to increase the battery lifetime. Due to the fact that the technology provides the required number of charge/discharge cycles, it is applicable for solar energy storage. Zeolites are a large group of natural or synthetic porous aluminosilicate minerals. Their porous structure provides good gas permeability. The gas diffusion layer of the electrode must also have good hydrophobicity. To prevent leakage of electrolyte from the battery, the zeolite was mixed with an appropriate amount of polytetrafluoroethylene, and the electrode was subjected to hot pressing according to a specially developed procedure. The experiments were performed in a specially designed test cell. Its construction ensures measurements of the bifunctional gas-diffusion electrode in a half-cell configuration applying a reference hydrogen electrode. The stationary volt-ampere characteristics and impedance tests were performed on the zeolite electrodes at certain operating points. The cell was subjected to cycling at charge/discharge current ± 2 mA/cm2, respectively. The obtained experimental results show that zeolite is a suitable material for carbon substitution in secondary metal air batteries. The zeolite/polytetrafluoroethylene (PTFE) ratio needs to be optimised in order to improve the gas permeability of the gas diffusion layer without compromising hydrophobicity. [ABSTRACT FROM AUTHOR]

This study aimed at determining the concentration and possibility of migration of potentially harmful elements (PHEs) in soils and mining and metallurgical waste in the Silesian-Cracow region. Our research was carried out in selected locations of Ruda Śląska, Świętochłowice, Bytom, and in the Olkusz region (Bukowno) in southern Poland. The concentrations of metals (e.g., Ag, Ba, Ca, Cd, Cu, Fe, Mg, Mn, Pb, Sr, Zn), metalloids (As, Sb), and sulphur were determined in 33 soil samples (with a depth range of 0.0–0.3 m) and 12 slag samples. These studies show an increased concentration of metals, metalloids, and sulphur, exceeding the level of regional geochemical background. The research results indicate that the degree of the chemical transformation of soils in the analysed regions of Ruda Śląska, Bytom, and Bukowno is advanced. This highlights the high concentrations of most metals, i.e., arsenic, antimony, and sulphur, in the surface layer of soils (topsoil) due to historic Zn-Pb ore mining and Zn and Fe metallurgy. The presence of both primary and secondary metal sulphides, sulphates, carbonates, oxides/hydroxides, silicates, and aluminosilicates was found in the mineral composition of soils and slags. [ABSTRACT FROM AUTHOR]

In the recycling of scrap metal, the establishment of the classification database of recyclables has the advantages of fast classification speed and high analysis accuracy. However, the classification and recycling of unknown samples become highly significant due to the extensive variety of standard metal samples and the challenges in obtaining them. In this study, a method for multi-element classification of automotive scrap metals in general environmental conditions was achieved by utilizing laser-induced breakdown spectroscopy (LIBS) and two-step clustering algorithm (K-means, hierarchical clustering). The two unsupervised learning algorithms were employed to cluster the LIBS spectral data of 60 automotive scrap metal samples rapidly and hierarchically. Three rare metal elements and three elements for distinguishing metal categories were selected to meet the recycling requirements. After applying the multiplicative scatter correction to the spectral data for calibration, the initial clustering clusters were determined using the Davies–Bouldin index, Calinski–Harabasz index, and silhouette coefficient. Then, the Kruskal–Wallis test was conducted on each cluster to check the significance. The clusters that failed the test were split and reclustered until all clusters met the significance criterion (α = 0.05). The accuracy of the proposed method for classifying the collected automotive scrap metals reached 97.6%. This indicates the great potential of this method in the field of automotive scrap metal classification. [ABSTRACT FROM AUTHOR]

The treatment of large amounts of copper slag is an unavoidable issue resulting from the high demand for copper during the global transition to a sustainable development path. Metal-rich copper slag might serve as a potential source of metals through secondary recovery. In this study, two copper slags (CS1 and CS2) with different metallurgical properties were characterized, focusing on secondary metal recovery. The X-ray diffraction (XRD) results show that fayalite (Fe2SiO4) and magnetite (Fe3O4) were the main crystalline phases in both CS1 and CS2. In addition, CS2 exhibited a more stable amorphous silicate network than CS1, which was attributed to the differences in the content of Si-O-3NBO linkages. The sequential extraction of Zn, Cu, Fe, and Pb from the slags was also explored, with the Cu content in CS1 being substantially lower than that in CS2. All metals were distributed in the F5 residue fraction. Cu was the most mobile metal as a result of the large proportion of soluble fractions (F1–F3), followed by Zn and Fe. This study explored the chemical speciation of Zn, Cu, Fe, and Pb from copper slags, which has practical implications for secondary metal recovery from such materials. [ABSTRACT FROM AUTHOR]

The efficient ethanol electrosynthesis from CO2 is challenging with low selectivity at high CO2 electrolysis rates, due to the competition with H2 and other reduction products. Copper‐based bimetallic electrocatalysts are potential candidates for the CO2‐to‐ethanol conversion, but the secondary metal has mainly been focused on active components (such as Ag, Sn) for CO2 electroreduction, which also promote selectivity of ethylene or other reduction products rather than ethanol. Limited attention has been given to alkali‐earth metals due to their inherently active chemical property. Herein, we rationally synthesized a (111) facet‐oriented nano Cu2Mg (designated as Cu2Mg(111)) intermetallic compound with high‐density ordered Cu3‐Mg sites. The in situ Raman spectroscopy and density function theory calculations revealed that the Cu3−δ $_{^{\rm{{\rm \delta} }} }$ −‐Mg−δ $_{^{\rm{{\rm \delta} }} }$ + active sites allowed to increase *CO surface coverage, decrease reaction energy for *CO−CO coupling, and stabilize *CHCHOH intermediates, thus promoting the ethanol formation pathway. The Cu2Mg(111) catalyst exhibited a high FEC2H5OH of 76.2±4.8 % at 600 mA⋅cm−2, and a peak value of |jC2H5OH| of 720±34 mA⋅cm−2, almost 4 times of that using conventional Cu2Mg with (311) facets, comparable to the best reported values for the CO2‐to‐ethanol electroreduction. [ABSTRACT FROM AUTHOR]

The impact of induction heating on the self-healing of asphalt mixture test specimens prepared with scrap metal and styrene–butadiene–styrene (SBS) modified bitumen was investigated in this study. In addition, the effects of waste metals used instead of aggregates in asphalt mixtures on the asphalt mixtures' mechanical properties were determined. To this end, asphalt mixtures were prepared to use two different percentages (inst aggregates of 50% and 100% aggregates) of waste metal in two different mill scale (cold mill scale and hot mill scale) and SBS in two different percentages (2% and 3%) to create prismatic and Marshall asphalt test specimens. Induction heating systems were used to determine self-healing properties. The samples were heated in five different heating times as 120 s, 100 s, 80 s, 60 s, and 40 s. To measure the performance of the recovery processing, five recovery cycles were performed for every asphalt sample. According to the results, the hardness of the mixtures, the mixes' fatigue life and load repetitions both shorten as the waste metal usage ratio in the asphalt mixtures increases. As both the amount of sludge and the amount of SBS in the asphalt mixtures increase, the maximum temperatures of the asphalt mixtures also increase. When the SBS ratio in the asphalt mixtures increases, the recovery rates increase. In addition, as the waste metal content in the asphalt mixture increases, an increase in HL values is observed. Finally, the general binding and rheological properties of SBS modified binders were evaluated. [ABSTRACT FROM AUTHOR]

Molten oxide electrolysis (MOE) is a promising electrochemical route to de-carbonize primary and secondary metal production. Developing MOE processes starts with laboratory experiments at temperatures > 1000 ∘ C lasting ~10 hours and requiring long heating/cooling times to protect furnace hardware. Before investigating MOE processes, crucibles must be selected that tolerate the required temperatures while minimizing chemical interactions with the oxide to control melt contamination and contain the melt. Unfortunately no general procedure guiding MOE crucible selection is documented. Here we focus on laboratory crucibles in air for two MOE melts: titania-sodia at 1100 ∘ C and neodymia-boria at 1300 ∘ C . After shortlisting generic crucible materials using Ashby's method, thermodynamic predictions were made for all-oxide titania-sodia charges using FactSage and cup test experiments were conducted on (i) all-oxide and carbonate charges for titania-sodia and (ii) neodymia-boria charges. While magnesia was predicted to be the best crucible for the titania-sodia melt, alumina was the best choice for both oxide and carbonate charges. The grain boundary networks of both magnesia and YSZ were infiltrated by the oxide and carbonate charges. Platinum was the best crucible for neodymia-boria melts. We show that compositional control during long, high-temperature MOE experiments requires experimental validation for specific chemistries every time. [ABSTRACT FROM AUTHOR]