نتایج جستجو برای: uranium ore

تعداد نتایج: 18938  

2016
Enrica Balboni Nina Jones Tyler Spano Antonio Simonetti Peter C. Burns

This study reports major, minor, and trace element data and Sr isotope ratios for 11 uranium ore (uraninite, UO2þx) samples and one processed uranium ore concentrate (UOC) from various U.S. deposits. The uraninite investigated represent ores formed via different modes of mineralization (e.g., highand lowtemperature) and within various geological contexts, which include magmatic pegmatites, meta...

2015
J. Krajko Z. Varga M. Wallenius K. Mayer

An improved sample preparation procedure for trace-levels of lanthanides in uranium-bearing samples was developed. The method involves a simple co-precipitation using Fe(III) carrier in ammonium carbonate medium to remove the uranium matrix. The procedure is an effective initial pre-concentration step for the subsequent extraction chromatographic separations. The applicability of the method was...

2017
Amrita Bhattacharyya Kate M Campbell Shelly D Kelly Yvonne Roebbert Stefan Weyer Rizlan Bernier-Latmani Thomas Borch

Historically, it is believed that crystalline uraninite, produced via the abiotic reduction of hexavalent uranium (U(VI)) is the dominant reduced U species formed in low-temperature uranium roll-front ore deposits. Here we show that non-crystalline U(IV) generated through biologically mediated U(VI) reduction is the predominant U(IV) species in an undisturbed U roll-front ore deposit in Wyoming...

2016
Judit Krajkó Zsolt Varga Maria Wallenius Klaus Mayer Rudy Konings

The applicability and limitations of sulphur isotope ratio as a nuclear forensic signature have been studied. The typically applied leaching methods in uranium mining processes were simulated for five uranium ore samples and the n(34S)/n(32S) ratios were measured. The sulphur isotope ratio variation during uranium ore concentrate (UOC) production was also followed using two real-life sample set...

Journal: :Talanta 2014
Judit Krajkó Zsolt Varga Ezgi Yalcintas Maria Wallenius Klaus Mayer

A novel procedure has been developed for the measurement of (143)Nd/(144)Nd isotope ratio in various uranium-bearing materials, such as uranium ores and ore concentrates (UOC) in order to evaluate the usefulness and applicability of variations of (143)Nd/(144)Nd isotope ratio for provenance assessment in nuclear forensics. Neodymium was separated and pre-concentrated by extraction chromatograph...

2017
India

Linkage between economic growth of any country and energy requirement is well known, and hence, sustainable energy resources are essential. During the past three decades the world was able to cope with an increasing energy demand by relying more on fossil fuel [1-3]. However, the progressively dwindling reserves of fossil fuel and a deeprooted concern about global warming, arising out of CO2 em...

Journal: :Journal of environmental radioactivity 2003
A Meinrath P Schneider G Meinrath

The Erzgebirge ('Ore Mountains') area in the eastern part of Germany was a major source of uranium for Soviet nuclear programs between 1945 and 1989. During this time, the former German Democratic Republic became the third largest uranium producer in the world. The high abundance of uranium in the geological formations of the Erzgebirge are mirrored in the discovery of uranium by M. Klaproth cl...

2005
Maozhong Min Huifang Xu Jia Chen Mostafa Fayek

We show evidence that the primary uranium minerals, uraninite and coffinite, from high-grade ore samples (U3O8N0.3%) in the Wuyiyi, Wuyier, and Wuyisan sandstone-hosted roll-front uranium deposits, Xinjiang, northwestern China were biogenically precipitated and psuedomorphically replace fungi and bacteria. Uranium (VI), which was the sole electron acceptor, was likely to have been enzymically r...

2001
Nobuaki Sato Yoshikatsu Tochigi Toshiki Fukui Takeo Fujino

Fly ash is generated from LWR nuclear power plant as a low-level waste, which is contaminated with a small amount of radioactive materials, composed mainly of uranium oxide. The constituents of the fly ash are similar to those of the ore; the major components of the ash are oxides of silicon, aluminum, sodium, magnesium, zinc, iron sodium and uranium. In this study, removal of uranium from the ...

2013
Andy Wilde

Albitite-type uranium deposits are widely distributed, usually of low grade (<1% U3O8), but are often large and collectively contain over 1 million tonnes of U3O8. Uranium is hosted in a wide range of metamorphic lithologies, whose only common characteristic is that they have been extensively mylonitised. Ore minerals are disseminated and rarely in megascopic veins, within and adjacent to albit...

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