The Use of Microanalytical Techniques to Measure the Distribution of Uranium and Plutonium Sorbed on Rocks and Minerals

Berry, Jessica; Bishop, H.E.; Cowper, M. M.; Fozard, Peter R.; McMillan, J.W.; Mountfort, Simon A.

doi:10.1524/ract.1994.6667.special-issue.243

Cited by 18 publications

(4 citation statements)

References 4 publications

(9 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This paper is focused on the reaction of aqueous U VI with rock-forming phyllosilicates, such as micas, that contain structural Fe II . Numerous experiments ( − ) have investigated this interaction in order to better understand the mobility of U in granitic terrains, which have been proposed as radionuclide waste disposal sites. However, Fe II can persist in the structure of phyllosilicates in soils.…”

Section: Introductionmentioning

confidence: 99%

Reduction of Uranyl in the Interlayer Region of Low Iron Micas under Anoxic and Aerobic Conditions

Ilton

Heald

Smith

et al. 2006

Environ. Sci. Technol.

View full text Add to dashboard Cite

The role of the interlayer region of three different FeII-poor micas (2.8, approximately 0.02, and 0.01 FeII atom %) in the reduction of UVI was investigated at pH approximately 4.3, low ionic strength, and 23 degrees C under both anoxic and aerated conditions in batch reactors for 1 to 10 days. U diffusion profiles were mapped with X-ray microscopy, and the oxidation state of U was tracked with XANES as a function of distance from the crystal edge. Peak U concentrations only reached about 0.006-0.0002 atom percent, where the full-width-at-half-maximums of the diffusion fronts were roughly 25-50 microm. Results for anoxic conditions indicated appreciable reduction of uranyl in all three micas with no measurable dependency on distance from the edge. Under aerobic (open to the atmosphere) conditions, U was still partially reduced, although to a lesser degree than for anoxic conditions, and UVI/Utot increased with time. Interestingly, reoxidation reached a plateau after about 3-10 days, leaving an appreciable proportion of U reduced. It is likely that measurable reduction occurred, despite low FeII, because U concentrations were even lower, where FeII/U ratios ranged from about 10(4)-10(2). A coupled diffusion-reduction model was developed that successfully simulated the proximal portion of the diffusion front. The results show that reduction of UVI in the interlayer of low FeII micas is, in principle, viable and that under aerobic conditions reduction is initially faster than reoxidation. This extends the range of possible environments where heterogeneous reduction of UVI by micas might occur.

show abstract

Section: Introductionmentioning

confidence: 99%

Reduction of Uranyl in the Interlayer Region of Low Iron Micas under Anoxic and Aerobic Conditions

Ilton

Heald

Smith

et al. 2006

Environ. Sci. Technol.

View full text Add to dashboard Cite

show abstract

“…Figure 2 gives the superimposed RBS spectra of Th sorbed on phlogopite showing the irreversibility of the Th retention by this mineral even by rinsing at 100 °C. Berry et al [20] studied at the AERE Har well nuclear microprobe, by a combination of RBS and PIXE, the sorption of uranium and plutonium on rocks and minerals. The energy of the used He-Ibeam was 2 MeV and its typical diameter 10 μτα.…”

Section: The Techniques and Their Applications To The Earth Sciencesmentioning

confidence: 99%

“…The same reaction was also recently applied by Godelitsas et al [25] to the determination of the structural characteristics of prehnite, a low-subgreenschist facies metamorphic mineral hydrothermally formed in basic igneous rocks. The 23 Na(p,a) 20 Ne reaction, which exhibits a narrow resonance (width: 0.6 keV) at 592 keV can be used for the quantitative determination and depth profiling of sodium in near-surface layers of minerals. The depth resolution, that can be achieved by this reaction in common silicate minerals is of the order of 10 nm.…”

Section: The Techniques and Their Applications To The Earth Sciencesmentioning

confidence: 99%

Application of Accelerator-based Analytical Techniques to the Study of Geological Materials

Μisaelides

2019

hnps

View full text Add to dashboard Cite

This contribution provides a short presentation of the applications of the most common accelerator-based analytical techniques to the earth sciences. These techniques offer high elemental selectivity and sensitivity as well as the possibility to determine the lateral and depth distribution of the elements under investigation in near-surface layers of geological materials and provide a powerful tool of investigation of geological, mineralogical, geochemical and cosmochemical processes.

show abstract

“…Investigations of the sites of U adsorption by the direct methods Rutherford backscattering, particle-induced X-ray emission (Alonso et al 2003), and secondary ion mass spectrometry (Berry et al 1994) demonstrate that adsorbed U on rock surfaces correlates with Fe(III) and Ti, but not with Si, Al, and K. Identified Ti minerals are rutile, sphene, and ilmenite. The silicates biotite, chlorite, epidote, and augite contain Fe(III) and adsorb U. Quartz and feldspars adsorb little or no U.…”

Section: General Observationsmentioning

confidence: 99%

Gain and loss of uranium by meteorites and rocks, and implications for the redistribution of uranium on Mars

Dreibus

Haubold

Huisl

et al. 2007

Meteorit & Planetary Scien

View full text Add to dashboard Cite

Abstract-Terrestrial alteration of meteorites results in the redistribution, gain, or loss of uranium and other elements. We have measured the maximum U adsorption capacity of a meteorite and two geochemical reference materials under conditions resembling terrestrial ones (pH 5.8). The basaltic eucrite Sioux County adsorbs 7 ppm of U. The result for the terrestrial granite AC-E is similar (5 ppm), while the basalt BE-N adsorbs 34 ppm of U.We have also investigated U adsorption in the presence of phosphate (0.01 M or less) in imitation of conditions that probably occurred in the earlier history of Mars. Such a process would have alterated Martian surface material and would be noticeable in Martian meteorites from the affected surface. The experiments demonstrated the counteracting effects of phosphate, which increases U adsorption, but decreases the quantity of dissolved U that is available for adsorption. U adsorption by AC-E increases to 7 ppm. The lowered value for BE-N of 8 ppm results from the low quantity of dissolved U in the volume of solution used.The results from the adsorption experiments and from leaching the Martian meteorite Zagami and a terrestrial basalt imply that the aqueous redistribution of U on Mars was moderate. Acidic liquids mobilized uranium and other metals, but present phosphate impeded the dissolution of U compounds. Some mobilized U may have reached the global sinks, while most of it probably was transported in the form of suspended particles over a limited distance and then settled.

show abstract

The Use of Microanalytical Techniques to Measure the Distribution of Uranium and Plutonium Sorbed on Rocks and Minerals

Cited by 18 publications

References 4 publications

Reduction of Uranyl in the Interlayer Region of Low Iron Micas under Anoxic and Aerobic Conditions

Reduction of Uranyl in the Interlayer Region of Low Iron Micas under Anoxic and Aerobic Conditions

Application of Accelerator-based Analytical Techniques to the Study of Geological Materials

Gain and loss of uranium by meteorites and rocks, and implications for the redistribution of uranium on Mars

Contact Info

Product

Resources

About