scholarly journals Use of micro X-ray absorption spectroscopy and diffraction to delineate Cr(VI) speciation in COPR

2013 ◽  
Vol 11 (3) ◽  
pp. 318-324
Keyword(s):  
Light Source ◽  
Absorption Spectroscopy ◽  
Chromium Oxide ◽  
X Ray ◽  
Ore Processing ◽  
Advanced Light Source ◽  
The Matrix ◽  
Elemental Maps ◽  
X Ray Absorption

The speciation of Cr(VI) in Cromite Ore Processing Residue was investigated by means of bulk XRD, and a combination of micro-XRF, - XAS and –XRD at the Advanced Light Source (ALS), Berkeley, CA, U.S.A.. Bulk XRD yielded one group of phases that contained explicitly Cr(VI) in their structure, Calcium Aluminum Chromium Oxide Hydrates, accounting for 60% of the total Cr(VI). Micro-analyses at ALS yielded complimentary information, confirming that hydrogarnets and hydrotalcites, two mineral groups that can host Cr(VI) in their structure by substitution, were indeed Cr(VI) sinks. Chromatite (CaCrO4) was also identified by micro- XRD, which was not possible with bulk methods due to its low content. The acquisition of micro-XRF elemental maps enabled not only the identification of Cr(VI)-binding phases, but also the understanding of their location within the matrix. This information is invaluable when designing Cr(VI) treatment, to optimize release and availability for reduction.

scholarly journals Photoelectron and X-ray Absorption Spectroscopy of Pu

2003 ◽  
Vol 802 ◽  
Author(s):  
J. G. Tobin ◽  
B. Chung ◽  
R. K. Schulze ◽  
J. D. Farr ◽  
D. K. Shuh
Keyword(s):  
Light Source ◽  
Absorption Spectroscopy ◽  
Photoelectron Spectroscopy ◽  
Future Studies ◽  
X Ray ◽  
Advanced Light Source ◽  
First Results ◽  
X Ray Absorption

ABSTRACTWe have performed Photoelectron Spectroscopy and X-Ray Absorption Spectroscopy upon highly radioactive samples of Plutonium at the Advanced Light Source in Berkeley, CA, USA. First results from alpha and delta Plutonium are reported as well as plans for future studies of actinide studies.

scholarly journals On the electronic configuration in Pu

2006 ◽  
Vol 986 ◽  
Author(s):  
J G Tobin ◽  
P Soderlind ◽  
A Landa ◽  
K T Moore ◽  
A J Schwartz ◽  
...  
Keyword(s):  
Detailed Analysis ◽  
Light Source ◽  
Absorption Spectroscopy ◽  
Photoelectron Spectroscopy ◽  
Electronic Configuration ◽  
X Ray ◽  
Sample Quality ◽  
Advanced Light Source ◽  
First Results ◽  
X Ray Absorption

AbstractX-Ray Absorption Spectroscopy (XAS) and Photoelectron Spectroscopy (PES) have been performed upon highly radioactive samples, particularly Plutonium, at the Advanced Light Source in Berkeley, CA, USA. First results from alpha and delta Plutonium are reported as well as a detailed analysis of sample quality.

Chemical study of passivating chromium oxide films by soft X-ray absorption spectroscopy

The Analyst ◽  
1994 ◽  
Vol 119 (4) ◽  
pp. 609 ◽  
Author(s):  
M. O. Figueiredo ◽  
A. Correia dos Santos ◽  
M. J. Carmezim ◽  
M. Abbate ◽  
F. M. F. de Groot ◽  
...  
Keyword(s):  
Absorption Spectroscopy ◽  
Chromium Oxide ◽  
Oxide Films ◽  
Chemical Study ◽  
X Ray ◽  
X Ray Absorption

X-ray absorption spectroscopy at a protein crystallography facility: the Canadian Light Source beamline 08B1-1

2012 ◽  
Vol 19 (6) ◽  
pp. 887-891 ◽  
Author(s):  
Julien J. H. Cotelesage ◽  
Pawel Grochulski ◽  
Ingrid J. Pickering ◽  
Graham N. George ◽  
Michel N. Fodje
Keyword(s):  
Light Source ◽  
Absorption Spectroscopy ◽  
Protein Crystallography ◽  
X Ray ◽  
X Ray Absorption

The State of Platinum in Pyrite Studied by X-Ray Absorption Spectroscopy of Synthetic Crystals

2019 ◽  
Vol 114 (8) ◽  
pp. 1649-1663 ◽  
Author(s):  
Olga N. Filimonova ◽  
Maximilian S. Nickolsky ◽  
Alexander L. Trigub ◽  
Dmitriy A. Chareev ◽  
Kristina O. Kvashnina ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Solid Solution ◽  
Absorption Spectroscopy ◽  
The State ◽  
Salt Flux ◽  
Chemical Modeling ◽  
Processing Technologies ◽  
X Ray ◽  
The Matrix ◽  
X Ray Absorption

Abstract Pyrite (FeS2) is a typical container of Pt in ores of magmatic and hydrothermal origin and in some carbonrich ores of sedimentary-diagenetic origin. Knowledge of the state of Pt disseminated in the matrix of pyrite, including local atomic environment (type of atoms in the nearest and distant coordination shells, coordination numbers, interatomic distances) and oxidation state, is necessary for physical-chemical modeling of platinum group element mineralization and for the improvement of Pt ore extraction and processing technologies. Here we report results of an investigation of local atomic structure of synthetic Pt-bearing pyrites by means of X-ray absorption spectroscopy (XAS). Synthesis experiments, performed at 580° and 590°C in a Pt-saturated system by means of salt-flux method, yielded crystals of pyrite with concentrations of Pt up to 4 wt %. Scanning electron microscopy (SEM) and electron probe microanalysis (EPMA) showed that the distribution of Pt within the pyrite grains is of zonal character, but within the distinct zones Pt is distributed homogeneously. Negative correlation between the concentrations of Pt and Fe was observed in the synthesized pyrite grains. The slope of the correlation line corresponds to the formation of the solid solution in the Pt-Fe-S system and/or to the formation of PtS2. The XAS experiments revealed the existence of two forms of Pt in pyrite. The main form is the solid solution Pt(IV), which isomorphically substitutes for Fe. The Pt-S distance in pyrite is ~0.1 Å longer than that of Fe-S in pure pyrite. The distortion of the pyrite crystal structure disappears at R >2.5 Å. The second Pt-rich form was identified by means of high-resolution transmission electron microscopy (HRTEM) as nanosized inclusions of PtS2. Heating experiments with in situ registration of X-ray absorption spectra resulted in partial decomposition (dissolution) of PtS2 nanosized inclusions with the formation of the solid solution (Fe1–xPtx)S2. Therefore, the PtS2 nanosized particles can be considered as a quench product. Our data demonstrate that both Pt solid solution and PtS2 nanosized inclusions (at high Pt content) can exist in natural Pt-bearing pyrites.

scholarly journals Correlation Of Magnetic Dichroism in X-Ray Absorption and Photoelectron Emission using Ultrathin Magnetic Alloy Films

1996 ◽  
Vol 437 ◽  
Author(s):  
J.G. Tobin ◽  
K.W. Goodman ◽  
G.J. Mankey ◽  
R.F. Willis ◽  
J.D. Denlinger ◽  
...  
Keyword(s):  
Light Source ◽  
Linear Dichroism ◽  
Magnetic Alloy ◽  
Photoelectron Emission ◽  
Alloy Films ◽  
X Ray ◽  
Magnetic Dichroism ◽  
Advanced Light Source ◽  
First Results ◽  
X Ray Absorption

AbstractWe have begun a program to characterize magnetic alloy overlayers using both magnetic x-ray circular dichroism (MXCD) and magnetic x-ray linear dichroism (MXLD). This will allow a direct comparison of MXCD-absorption and MXLD-photoelectron emission. First results from the Advanced Light Source will be presented.

scholarly journals I20; the Versatile X-ray Absorption spectroscopy beamline at Diamond Light Source

2009 ◽  
Vol 190 ◽  
pp. 012038 ◽  
Author(s):  
S Diaz-Moreno ◽  
S Hayama ◽  
M Amboage ◽  
A Freeman ◽  
J Sutter ◽  
...  
Keyword(s):  
Light Source ◽  
Absorption Spectroscopy ◽  
X Ray ◽  
X Ray Absorption
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