Subcomputer
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Photoreduction of Uranyl Nitrate
There's a possibility I'm getting over my head with this one, but here goes.
It's my understanding that one of the effects of UV light on the Uranyl ion is a reduction from Uranium (VI) to (IV). This has been previously used in
photography, i.e. the "Uranotype" process.
Getting to my question, in the photographic processes, the Uranyl Nitrate was never "pure" - it was often mixed with other photosensitive metals that
were reduced in the process, coated on paper with undescribed impurities, etc. What would happen in a large crystal of Uranyl Nitrate, with an
adequate UV source, over a significant length of time?
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careysub
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Quote: Originally posted by Subcomputer  | There's a possibility I'm getting over my head with this one, but here goes.
It's my understanding that one of the effects of UV light on the Uranyl ion is a reduction from Uranium (VI) to (IV). This has been previously used in
photography, i.e. the "Uranotype" process.
Getting to my question, in the photographic processes, the Uranyl Nitrate was never "pure" - it was often mixed with other photosensitive metals that
were reduced in the process, coated on paper with undescribed impurities, etc. What would happen in a large crystal of Uranyl Nitrate, with an
adequate UV source, over a significant length of time? |
The uranyl nitrate crystal would fluoresce brightly, but I don't know if it would show a reaction the way silver nitrate crystals darken with sunlight
exposure.
Behavior in solid crystal form is generally quite different from aqueous solution for most materials.
You might find it interesting to investigate the Westinghouse Lamp Division process developed and used during the Manhattan Project for photochemical
reduction of uranyl nitrate to potassium uranous fluoride:
http://www.google.com/patents/US2690421
It was dropped from use after several months.
But what was old is (relatively) new, here is an Oak Ridge paper from the 1980s investigations UV uranyl niitrate reduction:
http://www.osti.gov/scitech/servlets/purl/10193761
[Edited on 29-9-2014 by careysub]
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Subcomputer
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Thank you, that does give me some help, particularly the discussion of reoxidation and scavengers in aqueous solution.
I was going to mention solution, but the concept of defining a "pure" solution got too complex in my mind what with molarity, possibility of
oxygenation, discussion of excess nitrate, uranyl, etc. that it slipped my mind.
I just realized that this subforum being what it is, a crystal could indeed be special if I were to broaden the hypothetical from the assumed depleted
stock to natural source or a more exciting isotope.
I think for now I'll look at reoxidation - maybe be able to figure out some experiments with it in solution, but the various papers such as the
Westinghouse Lamp Division process that attempt to make functional use of this are very intriguing as a next step.
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