نتایج جستجو برای: rare earth elements ree

تعداد نتایج: 590324  

Journal: :Chemosensors 2022

The increasing demand for rare earth elements (REE) requires faster analysis techniques their rapid exploration. Laser-induced breakdown spectroscopy (LIBS) has on-site and real time capability. However, interference the weaker emission of minor REEs are key challenges complex REE spectra. Using simulations experimental results, we presented essential principles improved line identification in ...

Journal: :Minerals 2021

Estonian phosphorite ore contains trace amounts of rare earth elements (REEs), many other d-metals, and some radioactive elements. Rare elements, Mo, V, etc. might be economically exploitable, while toxic should removed before any downstream processing for environmental nutritional safety reasons. All untreated hazardous remain in landfilled waste much higher concentration than they occur natur...

Journal: :Waste management 2015
Sandra R Mueller Patrick A Wäger Rolf Widmer Ian D Williams

The mining of material resources requires knowledge about geogenic and anthropogenic deposits, in particular on the location of the deposits with the comparatively highest concentration of raw materials. In this study, we develop a framework that allows the establishment of analogies between geological and anthropogenic processes. These analogies were applied to three selected products containi...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه شهید بهشتی - دانشکده علوم 1372

a simple, sensitive and selective method for solvent extraction and spectrophotemetric determination of lanthanum (ii) europium (iii), and cerium (iii) is described , the rare earth metals are extracted into chloroform solution of n-phenylbenzohydroxamic acid (pbha) at ph 9-10 various parameters are studied to optimize the extraction conditions. the molar absorptivity is found to increase from ...

2016
Susanne Sjöberg Bert Allard Jayne E. Rattray Viktor Sjöberg Stefan Karlsson

The Ytterby mine, Sweden, is known for the discovery of eight elements, including yttrium and five of the rare earth elements (REE). The mine was in operation from 1750 to 1933 and was after closure used as a storage depot for fuel from the 1950s to 1995. A tunnel was opened in the 1950s through the bedrock into the mine to allow access to the storage depot. Recent water monitoring campaigns (2...

2010
Paolo Gabrielli Anna Wegner Jean Robert Petit Barbara Delmonte Patrick De Deckker Vania Gaspari Hubertus Fischer Urs Ruth Michael Kriews Claude Boutron Paolo Cescon Carlo Barbante

We present the first Rare Earth Elements (REE) concentration record determined in 294 sections of an Antarctic ice core (EPICA Dome C), covering a period from 2.9 to 33.7 kyr BP. REE allow a detailed quantitative evaluation of aeolian dust composition because of the large number of variables (i.e. 14 elements). REE concentrations match the particulate dust concentration profile over this period...

2004
V. O. Polyakov M. A. Nearing

The development of soil conservation plans and evaluation of spatially distributed erosion models require knowledge of rates of soil loss and sedimentation on different landscape elements and slope positions. Characterization of soil erosion rates and patterns within watersheds is important for the understanding of erosion processes and landscape evolution. Experimental data that show spatial t...

2007
Gerald R. Dickens Robert M. Owen

ODP Site 762 (eastern Indian Ocean) includes a section of sediment that spans the Cenomanian-Turonian Boundary (CTB) and was deposited along a continental margin during a period of widespread oceanic 09. deficiency. The rare earth element (REE) content of preand post-boundary sediment is similar to that of present-day continental slope material deposited in well-oxygenated seawater, whereas the...

Journal: :Analytica chimica acta 2008
D Dick A Wegner P Gabrielli U Ruth C Barbante M Kriews

Inductively coupled plasma mass spectrometry (ICP-MS) is a suitable tool for multi-element analysis at low concentration levels. Rare earth element (REE) determinations in standard reference materials and small volumes of molten ice core samples from Antarctica have been performed with an ICP-time of flight-MS (ICP-TOF-MS) system. Recovery rates for REE in e.g. SPS-SW1 amounted to approximately...

Journal: :Ecotoxicology and environmental safety 2016
Henning Herrmann Jürgen Nolde Svend Berger Susanne Heise

Rare earth elements (REE) used to be taken as tracers of geological origin for fluvial transport. Nowadays their increased applications in innovative environmental-friendly technology (e.g. in catalysts, superconductors, lasers, batteries) and medical applications (e.g. MRI contrast agent) lead to man-made, elevated levels in the environment. So far, no regulatory thresholds for REE concentrati...

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