Fractional Crystallisation

cloa513
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Fractional Crystallisation

Post by cloa513 » Oct 05, 2011 12:20 am

Given a mixture of many stable fission derived fluorides, how much separation is possible by gradually cooling and separating the components?

Eric_Robinson
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Re: Fractional Crystallisation

Post by Eric_Robinson » Mar 12, 2012 8:56 pm

That is a really good question.

I had always imagined some sort of equilibrium staged separation with various solvents, or possibly distilling (At really high temperatures), or using molecular sieves/adsorbants etc.

Seeding with desired crystals, keeping the mixture at very precise temperature, and walking away has a lot of appeal especially with radioactive fission products. Since the system is simpler and there is less to go wrong.

I wonder what the effect of radiation is on the surface chemistry of a crystal.

Cyril R
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Re: Fractional Crystallisation

Post by Cyril R » Mar 13, 2012 5:21 am

I'm not sure if fractional crystallization is all that simple. For one thing, there are a lot of different fission products, and if some of these form low melting eutectics that we don't know about, they would tend to stick together in a eutectic phase. I'm not sure if that's good or bad, but it is probably not simple. The lack of chemical reactions is always good when processing fission products (it avoids making too much secondary waste).

KitemanSA
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Re: Fractional Crystallisation

Post by KitemanSA » May 22, 2012 7:15 am

Isn't this what zone-melt refining is all about?
DRJ : Engineer - NAVSEA : (Retired)

Cyril R
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Re: Fractional Crystallisation

Post by Cyril R » May 22, 2012 8:14 am

KitemanSA wrote:Isn't this what zone-melt refining is all about?
The problem could be that product and waste stick together in some eutectic phase or something. Then the concept wouldn't work well.

KitemanSA
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Re: Fractional Crystallisation

Post by KitemanSA » Feb 09, 2014 12:57 pm

since they are all fluoride salts, perhaps disolving them and then running a ... heck, I don't remember the term, but as a kid we basically let a mixture of salts sit in a bowl with a strip of filter papar in it and the different salts with different solubilities would crystalize on different locations on the strip. Can that be scaled up and be useful?
DRJ : Engineer - NAVSEA : (Retired)

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