"rare earth concentration"

Determination of Concentration of Rare Earth Ions Yb3 ...

Crystals of solid solutions (R x Y 1-x) 3 Al 5 O 12 (where R is rare earth ion Er 3+, Yb 3+, Tb 3+, Ho 3+, Tm 3+) with garnet structure were grown.The temperature dependencies of magnetic susceptibility for these crystals were obtained. On the basis of measurement of magnetic susceptibility a non-destructive technique for determining the concentration of rare earth ions in yttrium-aluminum ...

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Concentrations of rare earth elements in topsoil from East ...

2008-1-3 · Fifty topsoil samples collected from 12 different regions of East China have been analyzed for rare earth elements (REEs). The average REE concentrations of the 50 topsoil samples are much higher than world average and are characterized by LREE-enrichment, HREE-depletion, Eu-depletion and Ce-enrichment. However, the REE concentration is not strongly affected by the climate of the sampling …

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Fabrication of high-concentration rare-earth doped optical ...

2021-10-10 · A process which uses rare-earth complexes of 2,2,6,6,-tetramethyl-3,5-heptanedione for uniform incorporation of rare earths in the cores of optical fibers is demonstrated. It is a vapor-phase transport process capable of producing fibers having a rare-earth content of at least 11 wt.% and easily lends itself to incorporation of multiple rare-earth dopants. The process gives high rare-earth ...

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RARE EARTH ELEMENT EXTRACTION AND CONCEN …

2019-7-1 · RARE EARTH ELEMENT EXTRACTION AND CONCENTRATION AT PILOT-SCALE FROM NORTH DAKOTA COAL-RELATED FEEDSTOCKS 3 2. PROJECT SUMMARY The University of North Dakota (UND) Institute for Energy Studies (IES) is teaming with Microbeam Technologies Incorporated (MTI), Barr Engineering Co., Rare Earth Salts (RES), and MLJ Consulting to

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Notes on the Potential for the Concentration of Rare Earth ...

Certain Central Appalachian coals, most notably the Fire Clay coal with a REY-enriched volcanic ash fall tonstein, are known to be enriched in rare earth elements. The Fire Clay tonstein has a greater contribution to the total coal + parting REY than would be …

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Concentration Mechanisms of Rare Earth Element-Nb-Zr …

Concentration Mechanisms of Rare Earth Element-Nb-Zr-Be Mineralization in the Baerzhe Deposit, Northeast China: Insights from Textural and Chemical Features of Amphibole and Rare Metal Minerals ... Northeast China, hosts a world-class resource of rare earth elements (REEs), niobium, zirconium, and beryllium. In contrast to previous ...

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Rare earth luminescence: A way to overcome …

2021-7-16 · Optically excited rare earth doped semiconductors suffer from the so-called concentration quenching effect,1–4 i.e. the intensity of the rare earth luminescence decreases with increasing dopant concentration. This effect dominates if the excitation energy is transferred between many

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Characteristics of Precipitation of Rare Earth Elements ...

The effective and selective leaching of rare earth elements (REEs) from various sources is frequently possible in practice by adopting a carefully coordinated strategy incorporating a selective precipitation of these elements from undesired ones in solution. In this study, the behavior of chemical precipitation of REEs with commonly used precipitants such as sulfate, carbonate, fluoride ...

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Concentration quenching effect in rare-earth doped …

2017-7-21 · Concentration quenching effect in rare-earth doped glasses by Chun XIA Concentration quenching effect in ytterbium (Yb) and neodymium (Nd) doped phos-phate glasses, thulium (Tm) doped germanate glass, and praseodymium (Pr) doped tellurite glass were studied. The fluorescence and lifetime of these rare-earth doped

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From coal, a new source of rare earths

2018-7-8 · The chemical processing involves a preprocessing step that removes unwanted contaminants from the ash, rare-earth concentration steps, extraction or recovery steps, and post-processing steps to ...

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Concentration of rare earth elements in the Faixa Placha ...

2020-8-1 · 1. Introduction. In recent years, the demand for rare earth elements (REEs) has become increasingly critical because of their scarcity in the world market (Roskill, 2007, Sanematsu et al., 2009).The price of heavy rare earth elements (HREEs) has been drastically increasing compared to that of light rare earth elements (LREEs) (Naumov, 2008).Thus, the critical global demand is for HREEs ...

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Concentration of rare-earth elements by sorption from ...

2019-9-18 · Figure 2 Sorption of rare-earth elements and iron from model solutions As follows from the figure, the degree of sorption of rare earth elements gradually increases with time and decreases in the series Y ± La ± Dy. This dependence is associated with the magnitude of the ionic radius of rare-earth elements and their concentration.

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Rare-Earth Elements

2017-11-27 · Rare-Earth Elements. By Bradley S. Van Gosen, Philip L. Verplanck, Robert R. Seal II, Keith R. Long, and Joseph Gambogi Chapter O of. Critical Mineral Resources of the United States—Economic and

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How to describe concentration quenching in rare earth ...

2012-11-29 · We report on two approaches to describe concentration quenching of rare earth doped semiconductors. The examples used are terbium doped aluminium nitride and silicon carbide. The aim of the presented work is to introduce a frame of description that …

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Rare earth element concentrations and Nd isotopes in the ...

2013-2-24 · Rare earth concentrations display nutrient like vertical profiles except at UPX where surface waters are enriched. At this station Nd isotopic compositions are clearly more radiogenic than in the open ocean, suggesting that boundary exchange process is releasing lithogenic rare …

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Rare earth luminescence: A way to overcome …

2012-10-11 · A model is developed to simulate the rare earth luminescence intensity in dependence of both the excitation rate and the dopant concentration. For low excitation rates, as in the case of photoluminescence investigations, concentration quenching is expected. In contrast for high excitation rates (as generally realized in cathodoluminescence experiments) concentration quenching can be …

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Rare earth elements: A review of applications, occurrence ...

2019-7-1 · Rare earth elements (REE) include the lanthanide series elements (La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) plus Sc and Y. Currently these metals have become very critical to several modern technologies ranging from cell phones and televisions to …

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Rare earth elements concentration in mushroom …

Background: Concentrations of 16 rare earth elements (REEs) and two actinides were determined for the first time both in cultivated mushrooms and in their production substrates by inductively coupled plasma mass spectroscopy. Moreover, the effect of REEs on cultivation parameters and composition of the final product was assessed, together with their potential use for authentication purposes.

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Estimating Rare Earth Concentrations

2020-12-14 · rare earth concentration estimate was then calculated for each sample as the sum of all element concentrations. The process was repeated, removing one known lab concentration at a time, to evaluate accuracies based on as few as two elements. The labora-

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Rare Earth Elements

Rare earth elements: A review of applications, occurrence ...

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(PDF) Separation and concentration of rare earth elements ...

Separation and concentration of rare earth elements from wastewater using. electrodialysis technology. Changbai Li, Deepika L Ramasamy, Mika Sillanpä ä, Eveliina Repo. PII: S1383-5866(20)31916-X.

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Determining Rare Earth Dopant Concentrations in …

2020-8-4 · T he fluorescence lifetimes of rare earth-doped fibres and waveguides were studied in this thesis to determine whether the fluorescence lifetime could be used as a means for determining the rare earth concentrations. The performance of rare earth-doped devices is dependent on many parameters, including the dopant concentration. Ac­

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Rare Earth Elements

2020-4-8 · name ''rare earth elements'' come to be associated solely with the specific set of elements it denotes today. In fact, in terms of their overall abundance in the Earth''s crust, the REE are not particularly rare. On average, as a proportion of the Earth''s continental crust, Cerium (Ce) is the most abundant, at 43 parts per million (ppm),

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Relationship between concentration of rare earth elements ...

Rare earth elements (REEs) are a group of elements whose concentration in numerous environmental matrices continues to increase; therefore, the use of biological methods for their removal from soil would seem to be a safe and reasonable approach. The aim of this study was to estimate the phytoextrac …

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Rare Earth Elements (REE) in Chondrites

2020-7-12 · "Rare Earth Plots" and the Concentrations of Rare Earth Elements (REE) in Chondritic Meteorites Randy L. Korotev. The following sets of concentration values have been used in the geochemical literature for the purpose of preparing plots of "chondrite-normalized" concentrations of REE against atomic number or inverse ionic radius.

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High Concentrations of Rare Earth Elements Found in ...

2017-11-29 · WASHINGTON, D.C. - The U.S. Department of Energy''s (DOE) National Energy Technology Laboratory (NETL) has found high rare earth element (REE) concentrations in coal samples taken from the Illinois, Northern Appalachian, Central Appalachian, Rocky Mountain Coal Basins, and the Pennsylvania Anthracite region.These highly concentrated samples are greater than 300 parts per …

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RARE EARTH ELEMENTS

2019-4-8 · Rare Earth Elements – Small Pilot, High Purity, REE Separation Systems ..... 8 Products from Coal and Coal Byproducts in the U.S. ... Resources Containing High Rare Earth Element (REE) Concentrations .....27 Rare Earth Ele ments (REE) from Coal and Coal By-Products - …

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Rare earth element concentrations and speciation in ...

1994-5-1 · The rare earth element (REE) concentrations of lake water from five alkaline lakes (i.e., Mono, Walker, Abert, Summer, and Goose Lakes) within the Great …

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Rare earth reserves by country 2020 | Statista

2021-4-6 · Rare earth elements, also called rare earth metals, are a group of 17 chemical elements. The largest subgroup within it are the 15 lanthanides. The two other elements are scandium and yttrium ...

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