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Rare earth elements are increasingly seen as critical raw materials and are currently the subject of geopolitical interests. To boost mineral exploration and extraction, it is important to ensure the rapid identification and mapping of rare earth elements, and non‐invasive spectroscopy‐based technologies could offer suitable solutions. We therefore investigated the potential of an integrated sensor system that combines hyperspectral and laser‐induced fluorescence imaging as a non‐invasive alternative characterization technique to conventional time‐consuming and costly chemical analysis. To test the analytical procedure we used representative material from the Siilinjärvi mine (Finland) and from Lofdal (Namibia). Laser‐induced fluorescence mapping results document the successful identification and efficient mapping of several rare earth elements within complex mineral matrices. The variation in laser‐induced fluorescence excitation wavelength facilitates the selective mapping of specific rare earth elements, thereby enhancing their differentiation capabilities. The combination with hyperspectral imaging provides mineral maps and cross‐validation. The major benefit of the integrated optical sensor system lies in the rapid acquisition of spatially continuous information on the occurrence and type of rare earth elements without the need for sample preparation. The non‐destructive character and operation in line‐scan mode opens manifold possibilities for in‐line applications with continuous sample throughput. We introduce a new integrated line‐scan sensor system that combines hyperspectral and laser‐induced fluorescence imaging as a non‐invasive alternative characterization technique specifically suited for rare‐earth element (REE) mapping and identification. We investigate in detail the potential and limitations in comparison to state‐of‐the‐art approaches using bulk or spectroscopy point‐wise acquisition methods. To test the capabilities, we used representative material from the Siilinjärvi mine (Finland) and from Lofdal (Namibia). Laser induced fluorescence mapping enables an efficient mapping of several rare earth elements within complex mineral matrices. Three excitation wavelength provide additional potentials for the selective mapping of specific rare earth elements, thereby enhancing their differentiation capabilities. The combination with hyperspectral imaging provides mineral maps and cross‐validation. The major benefit of the integrated optical sensor system lies in the rapid acquisition of spatially continuous information on the occurrence and type of rare earth elements. The non‐destructive character and operation in line‐scan mode open manifold possibilities for in‐line applications with continuous sample throughput.

Rare earth elements (REEs) have become increasingly important to our modern society due to their strategic significance and numerous high technological applications. Regolith-hosted heavy rare earth element (HREE) deposits in South China are currently the main source of the HREEs, but the ore-forming processes are poorly understood. In these deposits, the REEs are postulated to accumulate in regolith through adsorption on clay minerals. In the Zudong deposit, the world's largest regolith-hosted HREE deposit, clay minerals are dominated by short, stubby, nanometer-scale halloysite tubes (either 10 or 7 Å) and microcrystalline kaolinite in the saprolite and lower pedolith and micrometer-sized vermicular kaolinite in the humic layer and upper pedolith. A critical transformation of the clay minerals in the upper pedolith is coalescence and unrolling of halloysite to form vermicular kaolinite. Microcrystalline kaolinite also transformed to large, well-crystalline vermicular kaolinite. This transformation could result in significant changes in different physicochemical properties of the clay assemblages. Halloysite-abundant clay assemblages in the deep regolith have specific surface area and porosity significantly higher than the kaolinite-dominant clay assemblages in the shallow soils. The crystallinity of clay minerals also increased, exemplified by decrease in Fe contents of the kaolinite group minerals (from ∼1.2 wt% in the lower saprolite to ∼0.35 wt% in the upper pedolith), thereby indicative of less availability of various types of adsorption sites. Hence, halloysite-abundant clay minerals of high adsorption capacity in deep regolith could efficiently retain the REEs released from weathering of the parent granite. Reduction in adsorption capacity during the clay transformation in shallow depth partially leads to REE desorption, and the released REEs would be subsequently transported to and adsorbed at deeper part of the soil profile. Hence, the clay-adsorbed REE concentration in the lower pedolith and saprolite (∼2500 ppm on average) is much higher than the uppermost soils (∼400 ppm on average). Therefore, weathering environments that favor the release of the REEs in the shallow soils but preservation of halloysite in the deep regolith can continuously adsorb REEs in the clay minerals to form economically valuable deposits.

In this study, the occurrence and leachability of rare earth elements and yttrium (REY) in medium-rank coal—meta-bituminous B coal from the southwestern part of the Upper Silesian Coal Basin in Poland—were investigated. The coal samples contained variable amounts of siderite, dolomite, calcite, kaolinite, illite, quartz, apatite, and pyrite in their mineral composition. A five-step sequential chemical leaching procedure was used, including deionized water, 3% HCl, 5% HNO3, 10% HNO3 with microwave assistance, and concentrated HCl–HF also with microwave assistance. The highest concentrations of ∑REY were observed in seam 404/1. Light REY (LREY) dominated the REY composition (>75%), while heavy REY (HREY) accounted for less than 10%. The chondrite-normalised REY patterns and total REY content indicate a clastic origin of REY-bearing minerals. The most efficient leaching occurred in stages IV and V. The solutions from stages I–III preferentially mobilised critical REY, while those from stages IV–V reflected the REY distribution in the coal. Based on the Coutl index, both coal and leachates from the later stages are classified as prospective REY resources. However, absolute REY concentrations should be considered when interpreting Coutl values. The positive correlation between apatite and kaolinite contents and ∑REE concentrations suggests their role in REY enrichment.

This study presents a robust methodology for differentiating uranium ore sources, a capability paramount for nuclear forensics and counter-proliferation efforts. The study analysed rare earth element (REE) signatures in 45 uranium ore-bearing soil samples, with 15 samples from each of three geologically distinct Tanzanian mining localities: Mkuju, Manyoni, and Bahi. Samples were subjected to acid digestion, and REE concentrations were precisely determined using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Subsequent chondrite normalization and multivariate statistical analyses, including Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA), were applied to the REE patterns using XLSTAT version 2025.1.3 (1431). While all sites consistently exhibited typical crustal Light Rare Earth Element (LREE) enrichment, multivariate analysis distinctly revealed statistically significant geochemical fingerprints for each deposit. Mkuju samples are characterized by a multi-stage history, with a primary factor (F1) accounting for 89.96 % of the REE variability and influenced by secondary factors (F2, F4). Their REE concentrations are exceptionally high, with Neodymium (Nd) reaching up to 10119.546 ± 161.809 µg/g. This is complemented by an enrichment of Heavy REEs (HREEs) and a positive Europium (Eu) anomaly, suggesting a hydrothermal, high-temperature system. The HCA for Mkuju identifies two distinct clusters, supporting a roll-front model. In contrast, Manyoni samples exhibit greater geochemical simplicity, with the first principal component explaining an overwhelming 98.82 % of the variance. The Pearson correlation coefficients exceed 0.95, indicating a clean, single-stage precipitation event. Their REE concentrations are also high, with Cerium (Ce) at up to 7712.418 ± 97.713 µg/g. This deposit is further distinguished by a strong positive Ce anomaly and a negative Eu anomaly, characteristic of a single-stage, oxidizing hydrothermal system. The HCA also supports a bimodal, roll-front model. The Bahi deposit, while also showing a single dominant PCA factor explaining 98.008 % of the variance, reveals a more complex origin shaped by supergene processes. This is evidenced by a negative Eu anomaly and a subtle negative Ce anomaly, suggesting an overprinting of the original lithogenic signature. The HCA is more complex, revealing three distinct clusters, which points to multiple sources or secondary overprinting. The REE concentration data for Bahi shows a mix of patterns, with most REEs highly correlated (r > 0.99) but Scandium (Sc) showing a much lower correlation (r ≈ 0.77 −0.84). These integrated findings collectively highlight the significant potential of chondrite-normalized REE patterns combined with multivariate statistics as a reliable tool for uranium ore soil provenance in nuclear forensics, thereby substantially enhancing global nuclear security. •A study developed a robust method to pinpoint uranium's origin through analysis of its Rare Earth Element (REE) signature.•ICP-MS and multivariate statistics (PCA/HCA) identified distinct geochemical fingerprints for three specific Tanzanian uranium deposits.•This novel approach provides a statistically rigorous tool for nuclear forensics.•The method allows for the precise tracing of illicit uranium materials back to their source.•Ultimately, the methodology significantly enhances global security and safeguards.

How mine tailings storage facilities (TSF) are managed reflects the history, regulatory framework, and environment of a country and locale of the mine. Despite many attempts to find an environmentally friendly strategy for tailings management and governance that balances the needs of society and the ecosystem, there is no worldwide agreement regarding the best practices for tailings management and governance. This article reviews the evolution of copper tailings management and governance in Chile, current practices, and changes that could be or may need to be made to improve practices in response to local environmental conditions and local tolerance for risk. The progress to date in developing a holistic tailings management strategy is summarized. This article also describes recent proposals for the best available technologies (BATs), case histories of Chilean TSF using conventional technology, thickened tailings, paste tailings, filtered tailings, water use reduction, tailings reprocessing to obtain rare earth elements (REEs), circular economy, submarine deep-sea tailings disposal, and ways to avoid failure in a seismic region. Finally, the Chilean tailings industry’s pending issues and future challenges in reducing the socioenvironmental impacts of tailings are presented, including advances made and lessons learned in developing more environmentally friendly solutions.

The importance of rare earth elements is increasingly recognized due to the increased demand for their mining and separation. This demand is driving research on the biology of rare earth elements. Biomolecules associated with rare earth elements include rare earth element-dependent enzymes (methanol dehydrogenase XoxF, ethanol dehydrogenase ExaF/PedH), rare earth element-binding proteins, and the relevant metallophores. Traditional (chemical) separation methods for rare earth elements harvesting and separation are typically inefficient, while causing environmental problems, whereas bioharvesting, potentially, offers more efficient, more green platforms. Here, we review the current state of research on the biological functions of rare earth element-dependent biomolecules, and the characteristics of the relevant proteins, including the specific amino acids involved in rare earth metal binding. We also provide an outlook at strategies for further understanding of biological processes and the potential applications of rare earth element-dependent enzymes and other biomolecules.

Ion-adsorption rare earth element (REE) deposits are a critical resource for strategic materials, yet their characterization and processing remain complex. This study provides a comprehensive mineralogical, chemical, and geochemical analysis of an ionic clay sample from a South American source, integrating multiple characterization techniques, including XRD, SEM-EDX, XPS, ToF-SIMS, TIMA-X, EPMA, and LA-ICP-MS. The results confirm that kaolinite and micas dominate the matrix, with monazite identified as the primary REE-bearing mineral. Yttrium and heavy REEs are primarily hosted in clays, indicating the necessity of ion-exchange leaching for effective extraction. Liberation studies reveal that monazite is best liberated in finer fractions, suggesting a need for targeted pre-concentration strategies. Surface chemistry analyses demonstrate the presence of REEs as adsorbed species and inner-sphere complexes, supporting the use of selective leaching techniques. The study highlights the economic and environmental considerations of REE extraction from ionic clays and provides insights into optimizing recovery processes while mitigating environmental risks. These findings contribute to the growing body of research aimed at diversifying REE supply sources and improving sustainable extraction methods.

The possibility of applying the system: weakly basic Amberlite IRA-68 resin-nitrilotriacetic acid (NTA) solutions for the separation of rare earth elements (REE) by ion exchange chromatography was investigated. Preliminary research results revealed that the affinity of REE towards the ion exchanger is closely correlated with the stability of their negative complexes that they form with NTA. Three separate groups of lanthanides could be distinguished, i.e. light (La, Ce, Pr, Nd), medium (Y, Sm, Eu, Gd, Tb, Dy, Ho, Er) and heavy (Tm, Yb, Lu, Sc). Moreover, it seemed that within the first and third groups it was possible to individually separate elements from each other. Based on the experimentally obtained relationships, the theoretically assumed course of the ion exchange reaction of anionic REE complexes with NTA on the Amberlite IRA-68 resin was confirmed. The influence of the ion exchanger particle size, column size and composition of the mobile phase, i.e. pH, NTA and neutral salt (NaNO 3 ) concentration, on the chromatographic separation of REE was investigated. It has been shown that the proper selection of these parameters makes it possible not only to divide REE into the three groups mentioned above, but also to individually separate some elements, i.e. La, Ce, Pr, Nd, Tm, Yb, Lu and Sc.

Studying the distribution of rare earth elements (REE) in the soil is crucial for understanding how natural factors influence the geochemical behaviour of such components in tropical lowland rainforests (TLRF) and tropical montane forests (TMF) that are differentiated based on their elevational range and floristics. Since little is known about REE in forest soils in Sri Lanka, eight (8) forest areas along an elevation gradient were investigated to determine the abundance of REE and its relationship to soil physicochemical properties, climatic factors, and vegetation parameters. Sampling was carried out over an area of a one-hectare plot; 17 representative soil samples were taken to a depth of 25 cm, and the REE content was quantified using ICP-MS. The mean REE content varied in all forest plots in the order Ce > La > Nd > Pr > Gd > Sm > Dy > Er > Tb > Yb > Eu > Ho > Lu > Tm. Higher light REE content (La-Nb) with depleted Eu content was a key feature in the forest soils. Altitude showed significant ( p  < 0.05) relationships with all studied parameters except clay content and heavy rare earth metal contents. The REE contents showed significant positive correlations ( p  < 0.05) with climatic factors such as precipitation and average temperature, as well as the vegetation parameters such as the Shannon-Wiener Vegetation Diversity Index and above-ground biomass. The results of this study highlight the significant influence of climate and vegetation on REE geochemistry. Further studies are required to elucidate the clay mineral adsorption of REE in forest soils of Sri Lanka.

The rare earth elements (REE), comprising 15 elements of the lanthanum series (La-Lu) together with yttrium (Y) and scandium (Sc), have become of particular interest because of their use, for example, in modern communications, renewable energy generation, and the electrification of transport. However, the security of supply of REE is considered to be at risk due to the limited number of sources, with dependence largely on one supplier that produced approximately 63% of all REE in 2019. As a result, there is a growing need to diversify supply. This has resulted in the drive to seek new resources elsewhere, and particularly on the deep-ocean floor. Here, we give a summary of REE distribution in minerals, versatile applications, and an update of their economic value. We present the most typical onshore methods for the determination of REE and examine methods for their offshore exploration in near real time. The motivation for this comes from recent studies over the past decade that showed ΣREE concentrations as high as 22,000 ppm in ocean-floor sediments in the Pacific Ocean. The ocean-floor sediments are evaluated in terms of their potential as resources of REE, while the likely economic cost and environmental impacts of deep-sea mining these are also considered.