Search Results (192)

With the rapid increase in global lithium demand, the exploration of newly discovered lithium in the bauxite of the Wenshan area in southeastern Yunnan has become increasingly important. However, the current research on clay-type lithium in the Wenshan area has primarily focused on local exploration, and large-scale predictive metallogenic studies remain limited. To address this, this study utilized multi-source remote sensing data from ZY1-02D and ASTER, combined with ALOS 12.5 m DEM and Sentinel-2 imagery, to carry out remote sensing mineral identification, structural interpretation, and prospectivity mapping for clay-type lithium in the Wenshan area. This study indicates that clay-type lithium in the Wenshan area is controlled by NW, EW, and NE linear structures and are mainly distributed in the region from north of the Wenshan–Malipo fault to south of the Guangnan–Funing fault. High-value areas of iron-rich silicates and iron–magnesium minerals revealed by ASTER data indicate lithium enrichment, while montmorillonite and cookeite identification by ZY1-02D have strong indicative significance for lithium. Field verification samples show the highest Li₂O content reaching 11,150 μg/g, with six samples meeting the comprehensive utilization criteria for lithium in bauxite (Li₂O ≥ 500 μg/g) and also showing an enrichment of rare earth elements (REEs) and gallium (Ga). By integrating stratigraphic, structural, mineral identification, geochemical characteristics, and field verification data, ten mineral exploration target areas were delineated. This study validates the effectiveness of remote sensing technology in the exploration of clay-type lithium and provides an applicable workflow for similar environments worldwide. Full article

The growing demand for rare-earth magnets has raised concerns over their price and the country’s risk of depleting the supply of rare-earth elements. These severe concerns have led to the study of rare-earth-free magnets that do not rely on rare-earth elements. Co-Zr-Mo-B alloys, one of the prospective candidates for rare-earth-free magnets, were produced by the melt-spinning technique and subsequent annealing. It was found that a small substitution of Mo for Zr in the Co-Zr-B alloys increased coercivity. The Co-Zr-Mo-B alloy with a Mo content of 2 at% showed a high coercivity of 6.2 kOe with a remanence of 40 emu/g. SEM studies showed that the annealed Co-Zr-Mo-B alloys had fine, uniform grains with an average diameter of about 0.6 μm. Further studies using STEM demonstrated that the ferromagnetic phase in the annealed Co-Zr-Mo-B alloys with high coercivity was composed of the Co₅Zr phase and the long-period stacking ordered (LPSO) phase. That is, the fine grains observed in the SEM studies were found to be ferromagnetic dendrites containing numerous twin boundaries of the Co₅Zr phase and its derived LPSO phase. Therefore, the high coercivity of the Co-Zr-Mo-B alloys can be attributed to the presence of ferromagnetic crystals of Co₅Zr and the derived LPSO phase. Full article

As global demand for rare earth elements (REEs) increases, maintaining the production and supply chain is critical. Technologies capable of being used in the field and in situ in the subsurface for rapid REE detection and quantification facilitates the efficient mining of known resources and exploration of new and unconventional resources. Laser-induced breakdown spectroscopy (LIBS) is a promising technique for rapid elemental analysis both in the laboratory and in the field. Multiple articles have been published evaluating LIBS for detection and quantification of REEs; however, REEs in their natural deposits have not been adequately studied. In this work, detection and quantification of two REEs, La and Nd, have been studied in both synthetic and natural mineral matrices at concentrations relevant to REE extraction. Measurements were performed on REE-containing rock and coal samples (natural and synthetic) utilizing different LIBS instruments and techniques, specifically a commercial benchtop instrument, a custom benchtop instrument (single- and double-pulse modes), and a custom LIBS probe currently being developed for in situ, subsurface, borehole wall detection and quantification of REEs. Plasma expansion, emission intensity, detection limits, and double-pulse signal enhancement were studied. The limits of detection (LOD) were found to be 10/14 ppm for La and 15/25 ppm for Nd in simulated coal/rock matrices in single-pulse mode. Signal enhancement of 3.5 to 6-fold was obtained with double-pulse mode as compared to single-pulse operation. Full article

The demand for rare earth elements (REEs) is continuously increasing due to the important roles they play in low-carbon and green energy technologies. Unfortunately, the global REE reserves are limited and concentrated in only a few countries, so the reprocessing of alternative resources like tailings is of critical importance. This study investigated carrier magnetic separation using coarse magnetite particles as a carrier to recover finely ground monazite from tailings. The monazite and carrier surfaces were modified by sodium oleate (NaOL) to improve the hydrophobic interactions between them. The results of zeta potential and contact angle measurements implied the selective adsorption of NaOL onto the surfaces of the monazite and magnetite particles. Although their hydrophobicity increased, heterogenous agglomeration between them was not substantial. To improve heterogenous agglomeration, emulsified kerosene was utilized as a bridging liquid, resulting in more extensive attachment of fine monazite particles onto the surfaces of carrier particles and a dramatic improvement in monazite recovery by magnetic separation—from 0% (without carrier) to 70% (with carrier). A rougher–scavenger–cleaner carrier magnetic separation can produce REE concentrates with a total rare earth oxide (TREO) recovery of 80% and a grade of 9%, increased from 3.4%, which can be further increased to 23.2% after separating REEs and the carrier. Full article

With growing demand for high-performance and high-efficiency motors, Axial Flux Permanent Magnet Motors (AFPMs) have received significant attention. These motors typically use rare-earth magnets due to their high magnetic and energy density. However, rare-earth magnets face challenges such as limited availability and price volatility, prompting research into reducing magnet usage. This study aims to reduce magnet consumption by applying a Consequent Pole (CP) structure to AFPMs. While CP structures improve magnet efficiency, they also introduce significant back-EMF ripple. To address this, an Intersect Consequent Pole (ICP) structure is proposed, which reduces ripple through alternating magnet placement within the rotor. Since ICP implementation is difficult in single-rotor AFPMs, a double-rotor, single-stator configuration was used. Simulation results show that the proposed design effectively reduces magnet usage and back-EMF ripple, demonstrating its potential for maintaining high performance with reduced rare-earth dependency. Full article

The global shift to low-carbon energy systems has significantly increased demand for critical raw materials like lithium, cobalt, nickel, rare earth elements, and copper. These materials are essential for renewable technologies and energy storage. However, their extraction and processing produce significant carbon emissions and face challenges from supply chain vulnerabilities and price volatility. This review examines the complex relationship between carbon pricing mechanisms—such as carbon markets and taxes—and raw material markets. It explores the strategic importance of these materials, recent policy developments, and the transmission of carbon pricing impacts through supply chains. The review also analyzes the systemic risks created by carbon pricing, including regulatory uncertainty, market volatility, and geopolitical tensions. We then discuss financial tools and corporate strategies for managing these risks, such as carbon-linked derivatives and supply chain diversification. Finally, this review identifies key challenges and suggests future research to improve the resilience and sustainability of raw material supply chains. Here, resilience is defined as the capacity to adapt to carbon pricing volatility, geopolitical disruptions, and regulatory shocks, while maintaining operations. The paper concludes that coordinated policies and flexible risk management are urgently needed to support a reliable and sustainable energy transition. Full article

Nd–Fe–B permanent magnets are vital for numerous key technologies in strategic sectors such as renewable energy production, e-mobility, defense, and aerospace. Accordingly, the demand for rare earth elements (REEs) enormously increases in parallel to a significant uncertainty in their supply. Thus, research and innovative studies are focus on the investigation of sustainable solutions to the problem and a closed-loop value chain. The present study is based on two benign-by-design approaches aimed at decreasing the recycling loop span by preparing standardized batches of EoL Nd–Fe–B materials to be treated separately depending on their properties, as well as using mechanochemical method for waste processing. The previously reported benefits of both direct recycling and mechanochemistry include significant improvements in processing metrics, such as energy use, ecological impact, technology simplification, and cost reduction. Waste-sintered Nd–Fe–B magnets from motorbikes were collected, precisely sorted, selected, and pre-treated. The study presents a protocol of resource-efficient recycling through mechanochemical processing of non-oxidized sintered EoL magnets, involving the extraction of Nd₂Fe₁₄B magnetic grains and refining the material’s microstructure and particle size after 120 min of high-energy ball milling in a zirconia reactor. The recycled material preserves the main Nd₂Fe₁₄B magnetic phase, while an anisotropic particle shape and formation of a thin Nd/REE-rich layer on the grain surface were achieved. Full article

This paper proposes a novel hybrid less-rare-earth permanent magnet (HLEPM) machine, which is designed to meet the demands of electric vehicle (EV) traction machines for high torque output and wide-speed-range high-efficiency performance. The designed machine features a unique hybrid permanent magnet arrangement, consisting of V-shaped rare-earth PMs and arc-shaped less-rare-earth PMs, respectively. The V-shaped rare-earth magnets can perform the flux-focusing effect well, not only enhancing the torque output capability but also improving the demagnetization with the standability of the arc-shaped less-rare-earth PMs during active short-circuit (ASC) conditions. First, the proposed machine is thoroughly designed and optimized to balance the torque capability and iron loss. Subsequently, the electromagnetic performance of the proposed HLEPM machine is evaluated using finite-element (FE) analysis and compared with that of a conventional double-layer V-shaped PMSM. Finally, the anti-demagnetization characteristics of the two machines under ASC conditions are analyzed in detail. The results validate the rationality and reliability of the proposed design. Full article

Apatite and rare earth elements (REEs) are vital to the European Union’s economic growth and resource security, given their essential roles in fertilizers, green technologies, and high-tech applications. To meet rising demand and reduce reliance on imports, the exploitation of domestic deposits has become increasingly important. This study investigates the beneficiation potential of ore from a carbonatite complex (Finland), focusing on the recovery of fluorapatite concentrate through froth flotation. This research addresses two key objectives: evaluating the potential for REE enrichment alongside fluorapatite concentration using conventional anionic and amine-based reagents, and assessing separation efficiency when partially substituting the most effective conventional collectors with bio-based organosolv lignin nanoparticles. Adequate recovery rates for apatite and REEs were achieved using common anionic collectors, such as hydroxamate and sarcosine, yielding P grades of 23.4% and 21.5%, and recoveries of 96.4% and 89.2%, respectively. Importantly, concentrate quality remained stable with up to a 30% reduction in conventional collectors and the addition of organosolv lignin. Bench-scale trials further validated the approach, demonstrating that lanthanum and cerium recoveries exceeded 71%, alongside satisfactory apatite recovery. Lignin nanoparticles were observed to interact with both minerals; however, the interaction was more pronounced in the case of phlogopite, which exhibited a markedly greater increase in surface hydrophilicity following treatment, suggesting a stronger affinity or surface modification effect, which was beneficial to the performance of the separation process. Full article

Environmentally friendly and low-emission extraction methods are needed to meet worldwide rare earth element (REE) demand. Within a greenhouse setting, this study aims to investigate the REE hyperaccumulation ability of four plant species (e.g., Phalaris arundinacea, Solanum nigrum, Phytolacca americana, and Brassica juncea) and the impact of amending REE-rich soil with biochar or fertilizer and watering with citric acid solution. Harvested samples were pyrolyzed, and the resulting bio-ores were acid-digested and underwent elemental analysis to determine REE content. Amending soil with fertilizer and biochar increased bio-ore production, while plant species explained the most variation in bioaccumulation factor. The results indicate that Phalaris arundinacea achieved the highest average REE concentration of 27,940 µg/g for the targeted REEs (comprising cerium, lanthanum, neodymium, praseodymium, and yttrium) and 37,844 µg/g for total REEs. It is also found that soil amendment and plant species are critical parameters in the design and implementation of Idaho-based REE phytomining operations. The life cycle assessment study estimated that the electricity demand of the greenhouse contributed the most to GHG emissions during the greenhouse study. Within the field study, electricity demand of the pyrolysis reactor was determined to be the largest producer of GHGs. The techno-economic analysis estimated that the total cost of growing P. arundinacea for six weeks on a one-acre field area is USD 6213, including 39%, 22%, 21%, and 18% of that cost derived from cultivation, biomass processing, soil treatment with fertilizer, and pyrolysis, respectively. It is concluded that the proposed low-emission extraction pathway, which combines phytomining, drying, and pyrolysis, is a promising sustainable approach for REE extraction, especially from REE-rich soil sourced in Idaho. Full article

The growing demand for rare earth elements (REEs) in high-tech and green energy sectors has prompted renewed exploration of unconventional sources. Drill cuttings, which are commonly discarded during subsurface drilling, are increasingly recognized as a potentially valuable, underutilized secondary REE reservoir. This review adopts a mineral-first lens to assess REE occurrence, extractability, and recovery strategies from drill cuttings across various lithologies. Emphasis is placed on how REEs associate with specific mineral host phases ranging from ion-adsorbed clays and organically bound forms to structurally integrated phosphates, each dictating distinct leaching pathways. The impact of drilling fluids on REE surface chemistry and mineral integrity is critically examined, alongside an evaluation of analytical and extraction methods tailored to different host phases. A scenario-based qualitative techno-economic assessment and a novel decision-tree framework are introduced to align mineralogy with optimal recovery strategies. Limitations in prior studies, particularly in characterization workflows and mineralogical misalignment in leaching protocols, are highlighted. This review redefines drill cuttings from industrial waste to a strategic resource, advocating for mineralogically guided extraction approaches to enhance sustainability in the critical mineral supply chain. Full article

The rapid advancements in electronics, electric vehicles, and green technologies have imposed increasingly stringent demands on copper-based materials. These requirements include high thermal and electricity conductivity, corrosion resistance, and strength properties at both room temperature and high temperatures. Rare-earth elements are excellent microalloying agents due to their typical metallic properties and highly active chemical characteristics; these properties and characteristics enable them to react with almost all elements except noble gases. The addition of rare-earth elements to copper and copper alloys can have several beneficial effects, such as impurity removal, purification, enhancement of the metallographic structure, and improved corrosion resistance. These effects can also raise the heat treatment temperature and enhance plastic processing, thereby further improving the overall properties of copper alloys. This review examines the influence of rare-earth elements (REEs) on copper and its alloys, along with their diverse industrial applications. It was found that elements such as La, Ce, Y, and Nd are commonly added to enhance properties like electrical conductivity, strength, corrosion resistance, purity, and hot workability in alloys such as pure copper, Cu-Ni-Si, Cu-Cr-Zr, and Cu-Fe-P. The review will lay a foundation and provide novel method for the development of advanced copper alloy. Full article

Wind power forms the major contributor to Germany’s goal of transforming the energy sector and becoming climate-neutral until 2045. The increasing installation of wind turbines comes with an increasing demand for rare-earth elements, especially neodymium, praseodymium and dysprosium, to produce high-performing magnets. However, these elements are considered to be critical raw materials because of their supply risk and economic importance. The European Commission aims to ensure supply chain resilience by improving the circularity of these critical raw materials. After an average of 20 years, wind turbines transition into their End-of-Life phase. This work aims to map the present and future potential of NdFeB magnets used in wind turbines in Germany to be introduced into a circular economy resulting in material amounts of potentially recycled magnets and secondary rare-earth elements considering different potential End-of-Life pathways. Full article

The growing demand for renewable energy positions it as a cornerstone for climate change mitigation and greenhouse gas emissions reduction. Although renewable energy sources generate around 30% of global electricity, their production and deployment involve significant environmental challenges. This review analyzes renewable energy projects from a life cycle perspective, focusing on environmental impacts throughout the supply chain. Particular emphasis is placed on the energy-intensive nature of manufacturing phases, which account for 60% to 80% of total emissions. The extraction of critical raw materials such as neodymium, dysprosium, indium, tellurium, and silicon is associated with emission levels ranging from 0.02 to 0.09 kg of carbon dioxide equivalent per kilowatt-hour for rare earth elements, along with an estimated average land degradation of 0.2 hectares per megawatt installed. Furthermore, the production of solar-grade silicon for photovoltaic panels consumes approximately 293 kilowatt-hours of electricity per kilogram, significantly contributing to the overall environmental footprint. Through a comprehensive review of the existing literature, this study integrates life cycle assessment and sustainable supply chain management approaches to identify environmental hotspots, quantify emissions, and propose strategic improvements. The analysis provides a structured, systematized, and data-driven evaluation, highlighting the relevance of circular economy principles, advanced recycling technologies, and digital innovations to enhance sustainability, traceability, and resilience in renewable energy supply chains. This work offers actionable insights for decision-makers and policymakers to guide the low-carbon transition. Full article

Currently, electric machines predominantly rely on costly rare-earth NdFeB magnets, which pose both economic and environmental challenges due to rising demand. This research explores recent advancements in machine topologies and magnetic materials to identify and assess promising solutions to this issue. The study investigates two alternative machine topologies to the conventional permanent magnet synchronous machine (PMSM): the permanent magnet-assisted synchronous reluctance machine (PMaSynRM), which reduces magnet usage, and the wound-field synchronous machine (WFSM), which eliminates magnets entirely. Additionally, the potential of ferrite and recycled NdFeB magnets as substitutes for primary NdFeB magnets is evaluated. Through detailed simulations, the study compares the performance and cost-effectiveness of these solutions against a reference permanent magnet synchronous machine (PMSM). Given their promising performance characteristics and potential to reduce or eliminate the use of rare-earth materials in next-generation electric machines, it is recommended that future research should focus on novel topologies like hybrid-excitation, axial-flux, and switched reluctance machines with an emphasis on manufacturability and also novel magnetic materials such as FeN and MnBi that are currently seeing synthesis challenges. Full article