Presence Of Rare Earth Elements Research Articles

Space and ground based spectroscopic studies and mineral chemistry of rare earth element bearing peralkaline rocks from Siwana Ring Complex, Rajasthan, India

The Neoproterozoic Siwana Ring Complex (SRC) in Barmer district, Rajasthan, India, contains a promising concentration of rare earth elements (REEs). This study uses PRISMA hyperspectral data to map potential high-REE locations using the Spectral Angle Mapper (SAM) classifier. Also, laboratory-based spectroscopy is used to analyse rock samples of peralkaline granite and rhyolite, using spectroradiometer in 400-2500 nm and Fourier Transform Infrared (FTIR) Spectroscopy in 400-4000 cm⁻1 regions. Diagnostic absorption features in the Visible Near Infrared (VNIR) and Short-Wave Infrared (SWIR) regions indicate the presence of REEs, alongside pyroxenes, amphiboles, and phyllosilicates. The data from the FTIR indicates the presence of minerals possessing Si-O, P-O and O-H bonds. Mineral chemistry and geochemistry confirm these findings, indicating the occurrence of REE-bearing minerals such as monazite, REE silicates, and apatite. Ce is found to be the most abundant REE. However, only absorption features related to Nd and Er or Ho are observed which means that these elements are indicators of high concentration of total REE in the samples. The map generated from the PRISMA data aligns well with geochemical data, proving the value of hyperspectral remote sensing in early exploration. This study also highlights laboratory spectroscopy as a valuable complementary tool in mineral exploration. This study provides spectral information for reference for future use on REE bearing peralkaline rocks.

Rare earth element assessment in Jezero crater using the Planetary Instrument for X-ray Lithochemistry on the Mars 2020 rover Perseverance: A case study of cerium

The “Planetary Instrument for X-ray Lithochemistry” (PIXL) X-ray spectrometer conducts in situ geochemical analyses of martian rocks and regolith interrogated by the Mars 2020 rover, Perseverance. In addition to quantifying primary rock-forming elements, PIXL can quantify trace elements that in turn can provide additional constraints on the geologic history of Mars. Accurate quantifications of trace elements can require additional analytical techniques to mitigate experimental, background, and crystalline effects within PIXL spectra. In this study, we focus on reducing the impact of these effects and investigate the potential presence of rare earth elements (REEs). The study specifically investigates cerium given its typical relative abundance in many geologic materials compared to other REEs and its potential to mimic fluorescence features produced by organics under deep UV excitation. A detailed analysis of PIXL targets analyzed through the first 887 martian days of the Perseverance mission did not produce any conclusive Ce detections. Phosphorus-enriched materials analyzed by PIXL are estimated to contain sub-675 ppm Ce and sulfate-enriched materials sub-450 ppm Ce. The method presented can help constrain limits on the abundance of additional trace elements of interest that also face a similar analytical burden. PIXL's potential to assess REE abundances, outside of yttrium, is limited for expected concentrations in surface materials. Determining most REE concentrations in materials interrogated by Perseverance will therefore likely require terrestrial analyses.

Selective separation of light and heavy rare earth elements from acidic mine waters by integration of chelating ion exchange and ligand impregnated resin

This study addresses the potential of sourcing Critical Raw Materials (CRMs) using Acidic Mine Waters (AMWs) as a secondary resource. AMWs, often viewed as waste, contain valuable metals like zinc and copper, as well as critical metals like magnesium and cobalt. Moreover, recent studies also reported the presence of Rare Earth Elements (REEs) at concentrations (mg/L) that make their extraction both technically and economically viable. The research focuses on a circular process to recover these metals from AMWs, specifically from the Aznalcóllar open-pit mine, which contains 216 mg/L of Al, 47 mg/L of Fe, 547 mg/L of Zn, and 18.56 mg/L of REEs. The proposed method involves pre-treating the AMW to remove Fe and Al, achieving removals of over 99.9 % and 90 %, respectively, at pH 4.5. Following this, transition metals like Zn, Cd, and Cu were removed as sulphides with a removal efficiency exceeding 99 %. This pre-treatment step reduced the concentration of competing metals in the ion-exchange process, thereby enhancing the recovery and purity of REEs. To separate heavy and light REEs, two types of resins in series were used: an impregnated resin (TP272) and a chelating resin (S930), which can be regenerated using sulphuric acid (H2SO4). The final recovery of REEs as oxalates was achieved using oxalic acid and ammonia at pH 1, with further optimization of the elution process to minimize ammonia consumption and undesired precipitation of other oxalates. Finally, REE oxalates with purities exceeding 90 % were obtained. This research demonstrates a sustainable method for efficiently recovering valuable REEs from AMWs, while also addressing environmental concerns related to hazardous sludge generation.

Adaptive vertical Plug-flow transition metal catalyzed Bioelectric membrane reactor for enhancing the efficient treatment of rare earth wastewater

The presence of rare earth elements (REEs) has a certain inhibitory effect on microorganisms, making the biological treatment of REEs wastewater an area of ongoing research and exploration. In this study, a vertical architecture anaerobic process and transition metal catalyzed bioelectromembrane reactor (IVABEMR) were integrated to continuously treat REEs, enhancing the potential for efficient treatment and recovery analysis. The IVABEMR demonstrated exceptional performance in removing La(III), Ce(III), Y(III), Eu(III) and Tb(III), the highest removal efficiency can reach 99.9%, 99.8%, 99.9%, 99.9%, 100%. Removal efficiency was enhanced by an electroactive electrode membrane driven by autogenous bioelectricity. Feature analysis revealed that self-released electroflocculated nucleus, recycling electromembrane reduction, and activated sludge had significant impacts on the decontamination outcomes of REEs. Functional microorganisms including Proteobacteria, Bacteroidetes, Firmicutes at phylum level survived at high abundance in the process, establishing an adaptive and stable relationship. This study provides technological optimization for efficient biological treatment, has the advantages of environmental protection and economy, and provides a feasible idea for the treatment of REEs wastewater.

Accumulation of rare earth elements in human gallstones: a perspective from dietary and human health

BackgroundGallstone disease poses a global threat to human health and is strongly linked to environmental factors. However, there is currently no data on the presence of rare earth elements (REEs) in human gallstones. This paper investigates the concentration and distribution of REEs in gallstones for the first time, aiming to explore the environmental implications on human health.MethodsA total of 25 gallstone samples were collected in Shanghai and the content of REEs was measured by Inductively coupled plasma-Mass Spectrometry (ICP-MS) to explore the distribution of REEs in gallstones.ResultsThe concentration of REEs in gallstones ranged from 4.89 to 190.8 ng/g (mean 39.21). In most of the gallstone analyses, REEs have been detected and generally attributed to environmental exposure or food contamination. The Y/Ho ratio of gallstones was lower than that of continental rocks, similar to that in the blood, indicating limited fractionation during fluid transport processes in the gallbladder.ConclusionsThe upper continental crust (UCC)-normalized REEs pattern in gallstones showed depletion of light REEs, while most showed enrichment of heavy REEs. Positive Gd anomalies were found in most samples, while few samples suggested anthropogenic influence. Whether exogenous inputs or in vivo biofractionation lead to changes in REEs fractionated patterns require further analyses.

The correlation between Rare Earth Elements and tin in granite, quartz vein, and weathered granite samples, in South Bangka, Bangka Belitung Islands, Indonesia

The presence of Rare Earth Elements (REEs) is often correlated with tin (Sn), particularly at placer deposits in the Bangka Belitung Islands. However, there is limited information on the correlation between Sn and REEs. Therefore, this study aimed to investigate the correlation between REEs and Sn using data analysis of Sn-W, REEs, Y, Th, and U in granite, quartz veins, and weathered granite samples from South Bangka. The statistical analysis carried out using the Pearson correlation coefficient and multivariate processing showed that Sn-REEs have a weakly negative correlation. The examination of genetic aspects through chemical analysis, mineralogy, and Scanning Electron Microscope (SEM) data, showed that Sn and REE originated from the same magmatic fluids but different depositional phases due to magmatic-hydrothermal processes. The results show that REEs were formed during the early magmatic crystallization as mineral and stannite (Cu-Sn) in granite, while Sn was enriched as cassiterite in the deposition of late-stage hydrothermal fluid in parental granite. Moreover, the variation in deposition stage and temperature during the formation process is depicted in statistically uncorrelated values for Sn and REEs.

Overview on Hydrometallurgical Recovery of Rare-Earth Metals from Red Mud

Aluminum is produced from its primary bauxite ore through the Bayer process. Although Al is important nowadays in the development of humanity, its production leads to the generation of a huge amount of waste, called red mud. Globally, the estimation of the stock of red mud is about 4 billion tons, with about 10 million tons located in Turkey. The presence of rare-earth elements (REEs) in crucial materials such as red mud makes it a major source of these elements. A number of methods have been developed for treating red mud, which are employed globally to recover valuable products. The application of a suitable method for REE extraction from red mud is a way to overcome the supply risk, contributing to reducing the environmental issues linked to red mud pollution. The current review summarizes the research on red mud processing and examines the viability of recovering REEs from red mud sustainably, utilizing hydrometallurgy and biohydrometallurgy.

Distribution of rare earth elements (REEs) in the feathers of gentoo penguins (Pygoscelis papua) from different geographical locations of the Antarctic peninsula area

Antarctica is the most remote and coldest regions of the planet, but the presence of REEs there has received little attention. This study assessed REE-contents in the feathers of adult gentoo penguins from Ardley Island, Kopaitic Island and Base O'Higgins. Field work was accomplished during 2011 (austral summer), and determination of elements was performed with ICP-MS. In general, REE-levels showed descending relations as follows: Ce > La > Y > Nd > Sc > Pr > Gd > Sm > Dy >Er > Yb > Eu > Ho > Tb > Tm > Lu. The data showed an increase of the levels of REEs from the lower part of the feather to the tip. This finding seems to be spatially dependent, but geochemical, anthropogenic conditions, feeding habits, sex, or even health status of birds should also be considered. It is a subject that requires deeper attention in future studies.

Impact of Rare Earth Elements on CaCO3 Crystallization: Insights into Kinetics, Mechanisms, and Crystal Morphology.

This study investigated the crystallization kinetics and mechanisms of calcium carbonate (CaCO3) in the presence of rare earth elements (REEs) including lanthanum (La), neodymium (Nd), and dysprosium (Dy). Through a comprehensive approach utilizing UV-vis spectrophotometry, powder X-ray diffraction, and high-resolution electron microscopy, we examined the effects of REEs on CaCO3 growth from solution at varying concentrations and combinations of REEs. Our findings highlight that even trace amounts of REEs significantly decelerate the rate of CaCO3 crystallization, also leading to alterations in crystal morphology and mechanisms of growth. The impact of REEs becomes more pronounced at higher concentrations and atomic mass, although the potential formation of poorly ordered REEs carbonate precursor phases can result in a decrease in the REE3+/Ca2+ ratio, influencing the crystallization rate of CaCO3. Vaterite and calcite were identified as the main crystallized polymorphs, with vaterite exhibiting distinct growth defects and calcite developing complex morphologies at higher REEs concentrations and an internal architecture suggesting a nonclassical growth route. We propose that REEs ions selectively adsorb onto different calcite surfaces, impeding growth on specific sites and resulting in intricate morphologies.

Multi-Layer Ceramic Capacitors in Lighting Equipment: Presence and Characterisation of Rare Earth Elements and Precious Metals

The need to reduce energy consumption in buildings, the emergence of light-emitting diode (LED) lamps in lighting around 2010, their long lifetime, and the 2025 target to use only LED lamps are changing the existing composition of Category 3 waste electrical–electronic equipment (WEEE) and creating expectations for simple, high-concentration recycling streams. In this study, multi-layer ceramic capacitors (MLCCs) detached from the lighting sector’s WEEE were characterised for the presence of rare earth elements (REEs) and precious metals (PMs). Their digestion was carried out with HNO3 and aqua regia on a heating plate and characterised using inductively coupled plasma optical emission spectroscopy (ICP-OES) and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX). The contents of REEs and PMs found in the MLCCs were 0.84 wt% and 0.60 wt%, respectively, and create an economic stored value that is essentially defined by PMs of 98.67% and by palladium (Pd) of 78.37%. The analysis showed that the content of the main elements was: neodymium (Nd) 0.366 wt%, yttrium (Y) 0.220 wt%, dysprosium (Dy) 0.131 wt%, silver (Ag) 0.467 wt%, and Pd 0.105 wt%. These results indicate the need for selective removal and separate recycling processes of MLCCs from WEEE drivers.

Sr and Nd Isotopes in Mineral Fractions of Ferromanganese Crusts from the Northernmost Pacific

A study of the isotopic compositions of neodymium and strontium in four mineral fractions of the hydrogenous ferromanganese crusts of the northernmost Pacific has been carried out for the first time. The relationship of the 87Sr/86Sr ratio and εNd value of the residual fraction in heterochronous layers of the ferromanganese crusts have shown that the sources of detrital matter are from rock weathering by the Yukon River, the Kuskokwim River, the Anadyr River and the rivers of Kamchatka. The amount of aluminosilicate impurity does not affect the isotopic compositions of the chemogenic (loosely bound, Mn oxides or manganese, hydrous Fe oxides or ferrous) fractions. The decreased εNd value in the ferrous fraction seems to be related to the presence of rare earth element (REE) phosphate complexes in seawater. The increase in those complexes is a consequence of melt waters entering the ocean during warming periods. Our data indicate that the carbonate REE complexes are not the dominant form of the REEs in the northernmost Pacific, which leads to the fact that the neodymium isotopic compositions of the manganese and ferrous fractions of hydrogenous ferromanganese crusts are different. A decrease in εNd value in the ferrous fraction may be a marker of a local increase in the surface water bioproductivity. Our data also show that the increase of the REE in the ferrous fraction relative to the manganese fraction does not reflect the participation of hydrothermal matter in the formation of mixed hydrogenous–hydrothermal crusts but is a consequence of an increase in the REE phosphate complexes.

Nonlinear optical effects in natural topaz

We investigate the nonlinear optical properties of natural topaz. For the first time, the observation of nonlinear phenomena related to multiphoton absorption effects, such as the up-conversion luminescence of the material defects, is reported in natural gems. In particular, we were able to detect the presence of the AlO4-related defects which are responsible for the change of the color of topaz as a consequence of irradiation with γ-rays as well as electrons and neutrons beams. Besides, the nonlinear spectral broadening of intense laser beams permits to spot of the presence of rare earth elements, such as Ytterbium and Neodymium, which are not found by means of standard characterization techniques of natural gems, e.g., those based on X-ray fluorescence, electron paramagnetic resonance, and linear optical fluorescence and absorbance measurements. In this sense, our results demonstrate that nonlinear optical effects induced luminescence measurements are a complementary, and previously unforeseen, technique for the characterization of the optical and physicochemical properties of natural gems. Finally, using intense infrared laser pulses allowed us to trigger extreme nonlinear effects, such as multiphoton ionization and conical emission. Our results will be of interest for the investigation of novel nonlinear optical effects in materials that are transparent in the whole visible spectral range and may give insights into the development of materials for nonlinear photonics.

Origin of ironstones of the Udokan Cu deposit (Siberia, Russia): A key study using SEM and LA-ICP-MS

Iron is an important element involved in the formation of sedimentary-hosted copper deposits. Its accumulation in sedimentary basins and subsequent redistribution ultimately affect the position of copper mineralization. The Udokan copperstone deposit contains considerable Fe reserves as magnetite and hematite. The Fe oxides form disseminated and layered aggregates in both Cu-bearing horizons and host metasandstones. The layered aggregates of Fe oxides contain detrital (zircon, chromite and apatite) and authigenic (a Th silicate) components. The ironstones bear chemical features both of clastic and chemical sediments. The enrichment of ironstones in Cr, Zr and Hf is due to the presence of relics of detrital chromite and zircon. The presence of rare earth elements (REEs), U, and Th in composition of ironstones is a result of chemical precipitation/sorption.According to the LA-ICP-MS data, Al, Mg, and V are the most significant trace elements of magnetite, whereas Ti and V are hosted in hematite. The extremely high Ti, Cr and Cu contents of magnetite are associated with inclusions of minerals of these elements. In hematite, the high Ti contents are due to inclusions of rutile or titanite. The correlations between the trace elements in Fe oxides reflect the mineral assemblages characteristic of two stages of sediment transformation: (i) earlier diagenetic with the formation of a hematite-rutile assemblage and early Cu sulphides and Th and REE mineralization and (ii) later metamorphic, which is related to the formation of magnetite metacrysts and recrystallization of Cu sulphides.The Fe-rich sediments formed at a river–sea geochemical barrier as a result both of sedimentation of clastic Fe oxides and flocculation of dissolved iron. The maturation of gel and lithification of sediments were accompanied by desorption of metals that accumulated in the ferruginous sediments. Some of them formed the authigenic phases (like Th), while others were isomorphically incorporated in other authigenic minerals (e.g., Nb, Ta and Sn in rutile).

Detection of Bastnäsite-Rich Veins in Rare Earth Element Ores Through Hyperspectral Imaging

Spectral indices are a well-established remote sensing tool showcased in many studies pertaining to fields such as agriculture, forest ecology, geology, soil sciences, vegetation, water resources, and urban development. In the case of geology, several indices already exist for the purpose of highlighting regions with interesting lithologies, such as iron oxides, aluminous clays, carbonates, and mafic to ultramafic minerals, based on signature absorption features in their reflectance spectra. However, in the literature, most indices often depend on the few, wide spectral bands used by spaceborne multispectral imagers such as Landsat 8 OLI, Terra ASTER, and Sentinel-2 MSI. Hyperspectral imagers are able to glean more detailed compositional information of a rock surface by operating with a myriad of narrow spectral bands, though the usage of these bands in spectral indices for mining and exploration purposes remains largely unexplored. We propose a new bastnäsite index capable of detecting the presence of rare earth elements and mapping their relative abundances across rock surfaces. Using four reference bands and four absorption bands in the visible to near infrared wavelength range, we apply this novel technique in a laboratory setting to ore samples extracted from the carbonatite body localized in the Sulfide Queen mine in Mountain Pass, California. Visual inspection is used to compare an index map to corresponding reflectance spectra for areas of known high and low rare earth element abundances, demonstrating its potential as a fast and straightforward means to assess rare earth element ore grade remotely.

Research on microstructure and mechanical properties of die casting Mg-4Al-1Si-3RE (Ce, La) and AS41 alloys

Mg-4Al-1Si-3Ce (ASCe), Mg-4Al-1Si-3La (ASLa), Mg-4Al-1Si-1.5Ce-1.5La (ASCeLa), and Mg-4Al-1Si (AS41) alloys were prepared by die-casting process, and the microstructure, tensile mechanical properties, friction and wear behavior and wear mechanism under different loads were systematically analyzed. It was found that die-casting Mg-4Al-1Si-3RE (Ce, La) (ASRE) alloys mainly contain three kinds of rare earth phases: lamellar REMg2Si2, rod-shaped Al11RE3, and granular Al2RE. Besides, a finer CeLaMg4Si4 phase exists in the ASCeLa alloy, which has a semi-coherent interface relationship with Mg2Si. Moreover, the Al11Ce3 phase in the ASCe alloy was not only attached to the end of the Mg2Si phase, but also perpendicular to the Mg2Si, thus hindering the growth of the Mg2Si phase. Among three rare earth alloys, the ASCeLa alloy possesses the smallest grain size of about 9 µm. In addition, its hardness, ultimate tensile strength, yield strength and elongation reach 85.55HV, 263 MPa, 167 MPa, and 12.03%, respectively, which are increased by 22.9%, 23.7% and 64.6% compared with typical die-casting AS41 alloy, respectively. At the same time, under the materials and test conditions given in this paper, compared with AS41 alloy, ASRE alloys have better friction and wear properties. Under the low load, the presence of rare earth elements improves wear resistance and prevents a drastic increase in local frictional heat. As the load increases, the amount of the wear debris increases, while the coefficient of friction decreases. When the load increases from 40 N to 120 N, the wear mechanism of ASRE alloys changes to delamination wear. Among three rare earth alloys, the ASCeLa alloy has the best friction and wear performance, which is attributed to the dispersion of the second phases with high hardness and high melting point along the grain boundaries and within the grains, solid solution strengthening effect of mixed rare earth elements and grain refinement. This research helps reveal the strengthening mechanism of Ce and La elements, and provides a reference for the design of high-strength die-casting magnesium alloys.

Highly-efficient and selective adsorption of phenols by GO-BT composite in the presence of rare earth elements

Recently, industrial activities have produced large quantities of wastewater containing metal ions (such as rare earth elements) or organic contaminants (such as phenols), which are difficult to be degraded or recycled. Carbon nanocomposites have been considered to be a kind of effective adsorbent for the separation/enrichment of organic substances or metal ions from aqueous solutions. To selectively adsorb/remove these contaminants, 2-bis(2-hydroxyethyl)amino-2-(hydroxymethyl)− 1,3-propanediol was utilized as a functional component to modify graphene oxide (GO) by a facile one-step coupling method. The fabricated GO-BT composite was characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, specific surface area analysis, thermogravimetric analysis and Zeta potential analysis. The equilibrium adsorption capacities of GO-BT composite for Y3+, Yb3+, Eu3+, Sm3+, Nd3+, La3+, Er3+, Pr3+, p-chlorophenol (PCP), p-methylphenol (PMP), phenol and aniline were tested to be 24.89, 28.13, 18.77, 57.46, 26.25, 33.12, 22.64, 6.529, 486.5, 391.8, 268.0 and 60.34 µmol g−1, respectively. The selectivity coefficient of GO-BT composite toward Y3+ against phenol was 0.2999, confirming its excellent adsorption selectivity for organic phenols rather than rare earth elemental (REE) ions. After 10 times of adsorption-desorption cycles, GO-BT composite maintained 80% removal rate and considerable recycling performance. The adsorption process could be better described by the pseudo-second order kinetic model and the non-linear Langmuir isothermal model. Adsorption thermodynamic studies demonstrated a non-spontaneous and exothermic process with decreasing randomness. This work can provide some references for fabricating GO-based adsorbents for selective removal of organic reagents in the flotation separation of REE ores.

Ethylene glycol metabolism in the poly(ethylene terephthalate)-degrading bacterium Ideonella sakaiensis.

Poly(ethylene terephthalate) (PET)-degrading bacterium Ideonella sakaiensis produces hydrolytic enzymes that convert PET, via mono(2-hydroxyethyl) terephthalate (MHET), into the monomeric compounds, terephthalic acid (TPA), and ethylene glycol (EG). Understanding PET metabolism is critical if this bacterium is to be engineered for bioremediation and biorecycling. TPA uptake and catabolism in I. sakaiensis have previously been studied, but EG metabolism remains largely unexplored despite its importance. First, we identified two alcohol dehydrogenases (IsPedE and IsPedH) and one aldehyde dehydrogenase (IsPedI) in I. sakaiensis as the homologs of EG metabolic enzymes in Pseudomonas putida KT2440. IsPedE and IsPedH exhibited EG dehydrogenase activities with Ca2+ and a rare earth element (REE) Pr3+, respectively. We further found an upregulated dehydrogenase gene when the bacterium was grown on EG, whose gene product (IsXoxF) displays a minor EG dehydrogenase activity with Pr3+. IsPedE displayed a similar level of activity toward various alcohols. In contrast, IsPedH was more active toward small alcohols, whereas IsXoxF was the opposite. Structural analysis with homology models revealed that IsXoxF had a larger catalytic pocket than IsPedE and IsPedH, which could accommodate relatively bulkier substrates. Pr3+ regulated the protein expression of IsPedE negatively; IsPedH and IsXoxF were positively regulated. Taken together, these results indicated that the combination of IsPedH and IsXoxF complements the function of IsPedE in the presence of REEs. IsPedI exhibited dehydrogenase activity toward various aldehydes with the highest activity toward glycolaldehyde. This study demonstrated a unique alcohol oxidation pathway of I. sakaiensis, which could be efficient in EG utilization. KEY POINTS: • IsPedH and IsXoxF complement IsPedE function in the presence of REEs. • IsPedI displayed the highest dehydrogenase activity toward glycolaldehyde. • Unique alcohol oxidation pathway of I. sakaiensis identified for EG utilization.

Kaman (Kırşehir-Türkiye) floritlerinin mineralojik ve gemolojik özellikleri

Fluorites are found in the region between Hamit, Karakütük, Bayındır and Yeniyapan villages of the Kaman District (Kırşehir-Türkiye). Fluorites are located in altered levels due to faults in quartz syenites containing gray-pink colored K-feldspar, plagioclase and quartz, amphibole and biotite type mafic minerals in the Upper Cretaceous aged. Central Anatolian Granitoids, Fluorites observed in purple and green in places, pink, yellow, white colors as veins reaching from a few centimeters to two meters, purple and green in places, pink, yellow, white colors.
 According to X-Ray diffraction (XRD) analysis results, quartz syenites are composed of quartz, feldspar and clay minerals; fluorites are composed of fluorite and quartz mineral combination. According to Wavelength Dispersive XRF (WDXRF) analysis results, it is observed that the amount of F in purple fluorites is 39.8%, the amount of CaO is 51.2%, the amount of SiO2 is 8.68%, the amount of F in green fluorites is 46.7%, the amount of CaO is 51.5%, and the amount of SiO2 is 1.15%. As a result of cathodoluminescence analysis, the presence of rare earth elements (REE) terbium (Tb), erbium (Er), dysprosium (Dy) and samarium (Sm) elements were observed in fluorites.
 In order for the fluorites in the region to be used as a gemstone; while features color variety, texture, and easy workability are revealed as positive features, features such as low hardness, low strength in atmospheric conditions, and cleaved structure in coarse crystals are determined as negative features. For this reason, the fluorites in the region can be used as gemstones, however it is important that they undergo improvement methods (saturation with epoxy).

Potential hot spots contaminated with exogenous, rare earth elements originating from e-waste dismantling and recycling

Dismantling and recycling e-waste has been recognized as a potential emission source of rare earth elements (REEs). However, the presence of REEs in typical regional soils has yet to be studied. Given the potential health implications of such soil contamination, it is vital to study the characteristics, spatial distribution, and pollution level of REEs caused by e-waste dismantling as well as determine the influencing mechanism. This study focused on Guiyu Town as an example site, which is a typical e-waste dismantling base. From the site, 39 topsoil samples of different types were collected according to grid distribution points. Soil profiles were also collected in the dismantling and non-dismantling areas. The REE characteristic parameters showed that the REE distribution was abnormal and was affected by multiple factors. The results of the integrated pollution index showed that approximately 61.5% of soil samples were considered to be lightly polluted. Spatial distribution and correlation analysis showed that hot spots of REE-polluted soil coincided with known, main pollution sources. Moreover, there was a significant negative correlation (p ≤0.05) between the REE concentration and the distance from the pollution source. E-waste disassembly and recycling greatly affect the physical and chemical properties of the surrounding soil as well as downward migration areas. In the disassembly area, REE accumulated more easily in the surface layer (0–20 cm). Geographical detector results showed that distance factor was the main contribution factor for both light rare earth elements (LREE) and heavy rare earth element (HREE) (q = 34.59% and 53.33%, respectively). REE distribution in soil was nonlinear enhanced by different factors. Taken together, these results showed that e-waste disassembling and recycling not only directly affected the spatial distribution of REEs, but that their distribution was also affected by land use type and soil properties.

Residual levels and health risk assessment of rare earth elements in Chinese resident diet: A market-based investigation

The widespread use of rare earth elements (REEs) in agriculture and high-tech industry resulted in significant release of REEs into the environment. However, there is a scarcity of studies focusing on the presence of REEs in the food worldwide. The present study investigated the residual levels of REEs in 14 representative food categories collected from 33 major cities of China. The measured total REEs (ΣREE) levels in the foods of aquatic origin were 174.97 μg kg−1 wet weight (ww), which was 6.35 times higher than those of terrestrial origin. It is interesting to observe a trophic dilution effect for REEs in both terrestrial and aquatic food samples. REEs in food samples at low trophic levels exhibited relatively high REEs levels; while for high trophic level food, relatively low REEs levels were observed. The distribution patterns of REEs varied across the different food categories and regions, with Ce being the most abundant REEs in all food samples, followed by La, Nd and Sm. High levels of ΣREE in food samples were observed in Midland, while low levels were found in the Northeast. Cereals was the dominant contributor to the estimated daily intake of REEs. The health risk of REEs by daily food consumption in China was acceptable.