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Re: Deuterium Source Operational

Posted: Sat Feb 12, 2005 10:49 pm
by Andrew Seltzman
I suppose it would work, though drierite would be better. You could probably get it on line, it's fairly common.


Andrew Seltzman
www.rtftechnologies.org

Re: Heavy Water Electrolysis Deuterium Source

Posted: Tue Feb 15, 2005 11:11 pm
by AllenWallace
Andrew,

How do you regulate the D2 volume? It seems to me that if you suck too much D2 into the fusor, you will suck the D20 into the drieite.

Allen Wallace

Re: Heavy Water Electrolysis Deuterium Source

Posted: Wed Feb 16, 2005 12:45 am
by Andrew Seltzman
The ultra fine needle valve at the bottom can be used to regulate deuterium flow. You can adjust the valve such that the production and consumption rates match. This is easier than one might suspect; the needle valve can be adjusted so that the production rate exceeds the consumption rate. Due to the design of the inner electrode, the produced deuterium will displace the heavy water until it is not in contact with the central electrode, stopping electrolysis. The level will continue to oscillate between touching and not touching the bottom electrode, and the system becomes self regulating. This can be varied for slightly higher rates as the conductivity of the system increases as the D2O climbs up the column, thus increasing production rate.

Andrew Seltzman
www.tftechnologies.org

Re: Heavy Water Electrolysis Deuterium Source

Posted: Wed Feb 16, 2005 9:45 am
by Richard Hull
This seems like a shining example of how to skirt the bottled gas issue.

I just wish that an RGA could be hooked up and look at the D2O mass number in the fusor chamber. I can't help but think that some D2O is getting through. This would probably not be a problem if it were on a ratio of one D2O molecule for every 50 D2 molecules.

Richard Hull

Re: Heavy Water Electrolysis Deuterium Source

Posted: Wed Feb 16, 2005 8:31 pm
by Roberto Ferrari
Richard,
When those doubts arose, is time to think about a palladium tube or membrane. Just will let go through only the D. Really super dry!
Roberto

Re: Heavy Water Electrolysis Deuterium Source

Posted: Thu Feb 17, 2005 5:21 am
by Adam Szendrey
Right now, i can only afford D2O. 25 ml of the stuff will give me about 30 l of D2 (theoretically). That's pretty sweet. 25 ml costs somewhere around 40-50 euros in germany.
Andrew, how efficiently does this system extract D2 from D2O. What i would like to know, is how much of x liters of theoretically avaliable gas can be extracted (for example, what percentage of that 30 liters can be extracted)?

Adam

Re: Heavy Water Electrolysis Deuterium Source

Posted: Thu Feb 17, 2005 9:21 am
by Richard Hull
To Roberto and Adam...........

A Pd membrane would be the best of all worlds, but barring obtaining an ultra thin section, even the thinnest foils would require some time for the D2 to, more or less, osmos through. Pressure differentials would, of course, drive the process.

The efficiency of D2 separation would be rather high in the electrolysis process, virtually 100%, provided the electrolye is chosen with great care, which I have mentioned in other posts. The loss of D2 to chemical combinations would be the sole loss of D2 in a D2O electrolysis setup. The platinum wire obviates metalo-hydrides to some degree, though platinum is capable of picking up hydrogen and an electrolyte like D2SO4 would avoid other issues, though the quantity of electrolyte is small even with hydrogenated electrolytes. The Sodium Carbonate would do fine with minimal combination.

As shown, I would think that there is little loss in this process. If deuterating of the Pt electrodes occurs, it will load up to a point and then cease once stuffed full allowing the freshly produced D2 to proceed out of the system. This could be checked after a period of operation by testing the pliability of the Pt. If it is stiff, then D embrittlement is apparent, indicating some loading.

The D20 used would have to be at minimum 98% pure. Some sort of statement to this effect with an analysis sheet would be nice. United Nuclear's product is of unstated purity, I think.

Richard Hull

Re: Heavy Water Electrolysis Deuterium Source

Posted: Thu Feb 17, 2005 12:07 pm
by Adam Szendrey
United Nuclear sells 99.999 % pure D2O (at least they claim that, but i guess there's no reason not to trust them).
100 mg (should be about 91 ml) costs $65. I aksed them a while back if they can ship D2O abroad (to Hungary), and they told be they can. 91 ml of D2O contains almost 110 liters of D2. I may order D2O from them, as here, in europe D2O is considerably more expensive.
See the page below:
http://www.unitednuclear.com/chem.htm

It's interesting to note what is written under the uses of heavy water:
"Easily make pure Deuterium gas for Fusor experiments, etc."
:)

Adam

Re: Heavy Water Electrolysis Deuterium Source

Posted: Thu Feb 17, 2005 12:18 pm
by Frank Sanns
Actually, the United Nuclear heavy water is STATED to be Ultrex 99.999%. I just have not seen it CONFIRMED anywhere!

It does sink though. My curiousity got the best of me as I was not sure that what I bought was anything other than tap water. Having sufficient quantity to experiment, I made a small (~2 cm^3) ice cube out of the UN D2O. I also cooled some distilled water down until it was starting to freeze at the edges. This gave me the longest "hang time" of the cube before it melted. I put the D2O cube in there and it went straight to the bottom. This is not an certified analysis but it sure is at least half D2O.

Frank S.

Re: Heavy Water Electrolysis Deuterium Source

Posted: Thu Feb 17, 2005 4:14 pm
by Adam Szendrey
It would be rather unfortunate if they would be selling some low purity stuff.I'm hoping they wouldn't try to sell some junk, as with proper equippment the purtity can be verified. If someone buys the stuff, and has the required equippment to test it, and finds that it's low purity, UN would get into a lot of trouble i think.... They would loose their credit, and a lot of costumers. D2O is not something that a lot of people buy, so it doesn't worth the risk to fake it (at least i hope).
Maybe they can proove the purity, if someone writes an email and asks them to.

Adam

Re: Heavy Water Electrolysis Deuterium Source

Posted: Fri Feb 18, 2005 10:50 am
by Richard Hull
I was given to understand at one time that they were making their own D20 via electrolysis, which would make it of extremely low grade, probably 75%.

However, it they are buying it by the drum from a reputable chemical firm with proper analysis sheets tagged to the lot and just re-bottling the stuff, then that is a totally different matter.


If I were remarketing something like this I would send along a copy of my order for the large lot drum (my cost covered up) along with a copy of the lot numbered analysis sheet from my supplier source. (it is common for chemical firms to supply lot analysis sheets with product.) This would instill a lot of buyer confidence in my re-marketed, re-packaged product. This is especially important when selling an isotopic form of water!

Frank's test helped a bit. It ain't tap water.

Richard Hull

Re: Heavy Water Electrolysis Deuterium Source

Posted: Fri Feb 18, 2005 8:30 pm
by Andrew Seltzman
I just bought 100g of heavy water on the web from a supplier that distributes NMR grade deuterated solvents. It cost $55, $10 less then Uniter Nuclear. It is 99.9%, was very profesionaly packed, and came with a MSDS. For larger quantities UN is not the best place to buy from (price wise).

Andrew Seltzman
www.rtftechnologies.org

Re: Heavy Water Electrolysis Deuterium Source

Posted: Sat Feb 19, 2005 11:10 am
by Roberto Ferrari
Richard,
Yo are right, Pd membrane will take a time to let the D2 go through.
An H2 commercial generator, with a cell of 6 Pd tubes -very thin walls- each with approx. 1000 mm2 active surface (approx. 120 mm long x 3 mm diam) can supply continuously 150 ml/min.
So, a single tube can approx. supply 25 ml/min. If not enough to feed the fusor, a modified Andrew's generator with a Pd tube can be run for an hour prior to use and the D2 collected in a small intermediary reservoir, in order to feed the fusor for a time.
Roberto

Re: Heavy Water Electrolysis Deuterium Source

Posted: Sat Feb 19, 2005 1:51 pm
by Adam Szendrey
What's the name of the supplier?

Re: Heavy Water Electrolysis Deuterium Source

Posted: Sat Feb 19, 2005 4:45 pm
by Adam Szendrey
I may have found them:

[color=#FF0000]admin note 160322[/color] : 11+ year old dead link to wilmad-labglass-dot-com has been deleted.

Somebody let us know if you an find another source of heavy water. [/color]


They list 100 g of 99.9 % D2O for $55.
I have sent an email to their regional representative, asking if this item is avaliable in this region.
Thanks for pointing out that there are cheaper sources for D2O, Andrew.

Adam

Re: Heavy Water Electrolysis Deuterium Source

Posted: Sat Feb 19, 2005 8:46 pm
by Andrew Seltzman
Yes, wilmad labglass was the supplier.

Andrew Seltzman
www.rtftechnologies.org

Re: Heavy Water Electrolysis Deuterium Source

Posted: Mon Feb 21, 2005 11:17 am
by Richard Hull
I assume the ml/min figures are for STP. If it is then 25ml/min STP would be more than enough.

Richard Hull

Re: Heavy Water Electrolysis Deuterium Source

Posted: Mon Feb 21, 2005 1:41 pm
by Roberto Ferrari
Yes Richard,

you are right, at STP conditions.

Roberto

Re: Heavy Water Electrolysis Deuterium Source

Posted: Thu Feb 24, 2005 12:38 pm
by Adam Szendrey
Hi guys,

I have sent an email a while back to UN, to ask them if they can provide a certificate.
Here is their reply:

"Yes, we can provide certification un request.
We supply Heavy Water to most Universities and they also require purity certification and ACS traceable certificates for their analysis and work.
Certification is available for any of out Reagent chemicals."

I haven't got a reply from Wilmad-Labglass yet.

Adam

Re: Heavy Water Electrolysis Deuterium Source

Posted: Sat Feb 26, 2005 8:42 am
by Starfire
Aldrich will supply Deuterium Oxide Ultra - D at 99.999 atom % isotopic purity certified ( cat ref 61.340-1 ) -- $120 for 10g

But Richard is correct - Palladium foil is the best drying filter/barrier but it takes a very long time for the D2 to permeate. It works better with a heated foil. Was used in;-

viewtopic.php?f=18&t=7715#p55674
image one.

The pallidium foil is the sealed filter in photo on the left calibrated electrolyliser. This calibrated tube ( 1ml syringe ) allowed gas transfer volume to be measured. The Oxygen side recorded the total O produced and was proportional to the total gas ratio at one bar.
The amount of gas needed for a Fusor is tiny

Re: Heavy Water Electrolysis Deuterium Source

Posted: Sun Feb 27, 2005 6:14 pm
by Andrew Seltzman
Looks nice. How fast did the D2 penatrate the foil? how thin was the foil?

Andrew Seltzman
www.rtftechnologies.org

Re: Heavy Water Electrolysis Deuterium Source

Posted: Sun Mar 06, 2005 2:44 pm
by Starfire
sorry for delay Andrew - I only get on at week ends now. Foil was hot rolled down from a 0.1 mm foil to about 0.005 and Indium soldered on to a SS ring washer then sealed in the plastic tube, but it took forever for the D2 to permeate the foil at 1 bar - the D2O had a bit of Sodium added and was electrolyzed at atmosphere. It would be better with the foil hot and the pressure higher - but how? This was a high school project and on a very small budget.

see Richards post -
viewtopic.php?f=6&t=2220#p11730
and followups

also of interest is Franks ;-
viewtopic.php?f=6&t=2440#p11950

Re: Heavy Water Electrolysis Deuterium Source

Posted: Thu Jun 16, 2011 12:10 pm
by Richard Hull
I upgraded this superb thread to a "FAQ".

Now a Simple search of "FAQ" in "titles" only within this forum will bring up this prime discussion on heavy water electrolysis.

Richard Hull