j_sum1
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Plutonium reactions - how'd they figure this stuff out?
Side topic from Finding small amounts of Pu or U235
That thread is likely destined for Detritus but it did raise some questions for me.
I posted this video which shows how Pu(NO3)4 is reduced to metallic plutonium. (The video presents a flow diagram of the process in the first 3
minutes then repeats the same information showing the actual equipment.)
Plutonium Metal Preparation
Two reactions interest me. One is the formation of a peroxide complex to precipitate plutonium nitrate.
The second is the use of elemental calcium and elemental iodine together to reduce PuF4 to Pu.
How did anyone figure out these were feasible routes?
Why would you expect the peroxide complex to be insoluble (and selective)? Why would you choose Ca and I2 for the reduction? I can't imagine anyone
had a significant amount of raw material to develop these processes. It must have been more than a hunch to derive the methodology.
And that second reaction seems a strange choice. I am guessing the reaction is
PuF4 + Ca + I2 --> Pu + CaF2 + 2IF
But other stoichiometries are possible.
Thoughts
(Placed in general chem because I am interested in the reactions and the mode of discovery.)
And, on second thoughts, moving to Radiochemistry.
[Edited on 29-9-2023 by j_sum1]
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j_sum1
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Thread Moved
29-9-2023 at 15:21 |
pantone159
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Part of the answer, was working with extremely small amounts of Pu in the early days, to study Pu chemistry and figure out purification that would
work. It was a triumph of nano-scale chemistry, especially with 1940's technology.
The Ca+I2 sounded strange to me also, but late in that video there was a comment that this heated up the Ca to where it worked for the reduction. I
wasn't sure what to make of that comment.
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UC235
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Uranium and thorium form insoluble peroxides, so it seems like a good place to start.
[Edited on 30-9-2023 by UC235]
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wg48temp9
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It seemed unlikely that any interhalogen compound would form, as it would combine with the plutonium metal.
Apparently, the plutonium is reduced by the calcium to form calcium fluoride. Additional calcium combines with the iodine to heat up the reaction, and
the formed calcium iodide reduces the melting point (fluxes) of the calcium fluoride to allow the plutonium to form a button at the bottom of the
crucible.
See Attachment: 4438226.pdf (894kB)
This file has been downloaded 55 times
I am wg48 but not on my usual pc hence the temp handle.
Thank goodness for Fleming and the fungi.
Old codger' lives matters, wear a mask and help save them.
Be aware of demagoguery, keep your frontal lobes fully engaged.
I don't know who invented mRNA vaccines but they should get a fancy medal and I hope they made a shed load of money from it.
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Pumukli
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j-sum, Ca as reducing agent seems fairly logical for me. Reductions by metals were widespread in those early days. The "tendency" of Ca2+ to combine
with F- and yield practically insoluble CaF2 makes this choice attractive.
Maybe, they tried these reactions on other "model compounds" previously and found them "worthwhile".
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j_sum1
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So, I2 is there as an energy boost and to create a flux
Makes sense.
Still, there is a lot of creative thinking to devise such a process.
I really am in awe.
Even determining MP would have been a challenge. If I was to guess, I would have gone a lot higher.
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unionised
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Fluorine gets its name from fluorspar which is essentially naturally occurring calcium fluoride.
Fluorspar gets its name from its use in metallurgy as a flux- very loosely it means "flow stone".
So roughly 1500 years before anyone knew about plutonium, they knew that calcium fluoride was a useful flux.
Hardly shocking that they chose to use it.
[Edited on 30-9-23 by unionised]
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