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LSD25
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Right, thanks Len that is great...
I bought one of the CIG welders on special, but I do have an old PC handy as well (a spare portable welder would be a useful thing to keep if
possible). You wouldn't happen to have an issue number/page for the Silicon Chip article you referred to would you, that would be very helpful
(although I am all at sea with electronic theory, I can certainly follow the step-by-steps they provide)?
The only reason I suggested plating is because I have found it fucking near impossible to find/purchase nickel sheet or pipe/tube. This is absurd in
fact, especially given that I used to live next to and work at a bloody nickel refinery.
Is any other material going to be comparable (even if greatly lesser so as long as it would not fuck the product or the electrolyte too quickly)?
Whhhoooppps, that sure didn't work
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len1
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The SC issue in question in July 2004 I believe. That article is only useful to show how an AT PS works (it actually shows how to step up the
voltage).
You need at 350W PS which is available for the newer PCs. The older tend to be 250W, which is not enough power, given you need 49Amps at 4.6V and
accounting for diode drop and converion efficiency. If you post high resolution pics of both sides of a 350W PS board in most likelyhood I can tell
you what mods you need to make.
Instead of Ni you can use SS sheet as second best. Its best if this is the nonmagnetic (high Ni) variety (dull in surface finish). Len
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watson.fawkes
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I've quite enjoyed reading through all the collected material here. I'll add a few notes.
Welders (as a rule) come in CV (constant voltage) and CC (constant current). CV is used for stick and MIG (GMAW); CC is used for TIG (GTAW). CC is
better for controlling electrolysis generally, since it will automatically adjust the voltage to maintain steady current, that is, constant molar flow
of electrons.
The boiling points of ammonia and chlorine are almost identical. Since refrigerators generally operate somewhat below the boiling point of the
refrigerant, a liquid ammonia loop should readily condense the gaseous chlorine coming off a NaCl cell.
Nickel sheet can be readily spot welded. A homemade spot welder can be built from an old microwave-oven transformer. Here's one such <a
href="http://www.instructables.com/id/Homemade-Spot-Welder/?ALLSTEPS">home-built spot welder</a>.
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12AX7
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Close, stick (SMAW) is also CC. TIG machines generally have finer control and more freatures than a stick machine; both come in AC or DC, and
obviously we want DC for this purpose (if not available, AC can be rectified with cheap components).
Tim
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watson.fawkes
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| Quote: | Originally posted by 12AX7
Close, stick (SMAW) is also CC. |
Yes, that's right; my brain fart.
I've got an old (== non-inverter, 2' cube of transformer) CC/CV welding supply, but I'm hesitant to use it for prototyping since the smallest
graticule on the ammeter is 10A.
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Picric-A
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I have thought of a easy and quick way to make sodium via electrolosis of NaOH.
I have yet to test this method as i am currently away from my lab but i feel the theary works.
Basically it is electrolosis but the electrode where the sodium is produced is a hollow graphite tube. The Na is produced and collected in the tube
and is protected form oxidation. Some Na may form on the outside of the tube but it can simply be scraped off.
At the end of elecrolosis the electrodes are removed and immedetly plunged into mineral oil and the electrodes are heated to remove the molten sodium.
Alterativly the electrodes can be broken up to remove the tube of Na inside.
[Edited on 19-9-2008 by Picric-A]
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not_important
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Your image is about twice as large as it should be, please resize it.
A problem with your concept is that most of the sodium will form on the outside of the tube(s). The current path is short, less voltage drop, there's
sort of a Faraday cage effect going on. You'd have to encapsulate your tubes in insulators to get around that.
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Picric-A
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Sealing them in glass would work but i agree it would be better to just find a way to tap it off...
Sorry bad idea 
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len1
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Quote: Originally posted by Organikum  | I was irritated all time because of Marvins remark that the molten sodium would give a shortening of the electric current between the "bell" and the
central electrode and make the design unworkable.
But I had done it and it worked.
How could this be?
Solution: The iron bell works is cooled by the air. At the edges inserted in the molten NaOH the NaOH solidifies and forms such an isolator on the
bell. This works because the temperatur of the NaOH is only slightly above the melting temperature of NaOH and the superior heattransfer properties of
iron compared to NaOH.
Try it!
Just put something from iron into just molten NaOH and you will see the solidified NaOH forming a stable protection layer on the iron. And this layer
wont dissolve also not after times.
Nothing shortens here.
Hope this answers your question Marvin? |
This reasoning doesnt work, because Na apart from being an excellent electrical conductor is also a great thermal conductor (used as medium in nuclear
power stations). Any sodium reaching from the electrode to the bell, and touching the frozen NaOH insulator coat, will rapidly melt it. That it must
do because one end of the Na pool is in contact with the electrode where the temperature is above melting by definition, and theres your electrical
contact. If this overhead electrode method worked for the author, his apparatus did not produce sufficient Na to reach the bell.
The problem is to produce continuous production, not a demonstration amount, which has been done by Davy in 1808. This has been well explained by
Castner, but by no one else. (My lesson in life is that people, and I mean professionals, often dont understand the essence of what they are talking
about if they have no first hand experience). The key claim he is making is in having discovered
1) That Na can be produced only over a narrow temperature range by Davys method
2) An inverted electrode must be used
3) The method works for Na and K
Note however an interesting thing: the patent claims both Na and K, however the former is described in great detail - in particular the temperature
range 300-320 degrees is mentioned, while no such detail is given for K at all - when this happens you immediately suspect the author is not
terribly familiar with that particular process. I greatly suspect the following
a) Castner never produced any substantial amounts of K with his method - he only claimed it as cover lest someone else should succeed. Even great
inventors it seems are prone to falsification
Also note the H2O vent is on the non-active side of the Ni anode. Either the anode is not circular, or the drawing is wrong - (the patent maintains
its a drawing of an actual apparatus)
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Broken Gears
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I have been working on a Castner cell for some time now. I´ve welded a bottom on a stainless tube (ø130mm) with a hole in the bottom for the
cathode.... well you know the setup.
But I cant find Ni anywhere to make a good cathode and I remembered some of you guys talking about, that copper wasn't a good choice for elektrodes.
Since Im not much of a chemist but more a machinist  , I dont really understand the
basic chemisrty of even this simple setup.
Can I just use Iron for both elektrodes? My 2nd choice would be copper or graphite, but I dont have much available.
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len1
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Yes the Castner cell is all about machining - I remember spending several weeks in the workshop.
You really need Ni for the anode, copper is no good. Iron just passes the test as a very distant second choice. The cell does will not produce
sodium long with iron, because the erosion will rapidly foul the bath.
Europe should be OK for Ni though. Id suggest looking for metal stockists on the net.
You dont have to be much of a chemist to understand Casners cell though - sodium hydroxide melts to give positive sodium and negative hydroxide ions.
The positive ions are attracted to the negative copper electrode where the gain a negative charge and become sodium metal.
[Edited on 17-5-2009 by len1]
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Broken Gears
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Okay so the center elektrode (cathode) sould be made of copper and the rind (anode) of Ni? So the copper elektrode will be "producing" the Na.
Can Titainium be used as either elektroede?
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Hydragyrum
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| Quote: Originally posted by len1 | ... The method works for Na and K
Note however an interesting thing: the patent claims both Na and K, however the former is described in great detail - in particular the temperature
range 300-320 degrees is mentioned, while no such detail is given for K at all - when this happens you immediately suspect the author is not
terribly familiar with that particular process. I greatly suspect the following
a) Castner never produced any substantial amounts of K with his method - he only claimed it as cover lest someone else should succeed. Even great
inventors it seems are prone to falsification... |
Well, I disagree that this means that he is falsifying results: a patent is not the same as a scientific paper - had he made unsubstantiated claims in
a published paper then one could accuse him of falsification. However, the purpose of a patent is quite different, and frankly I'm surprised that he
did not claim his method for all of the alkali metals (unless certain examples had been shown not to work prior to his publication? - I haven't read
it firsthand so ... ). A scientific paper is written by scientists for
scientists; a patent can be considered as being written by lawyers for lawyers.
A patent is to claim an idea backed up by actually doing it - but he only needs to demonstrate it in one example - in this case for M = Na - and can
still claim the case for M = K as his idea too.
One thing I've noticed about a lot of patents is that they are not always so very easy to reproduce; I suspect that they write the bare minimum with
the deliberate intention of being obscure enough to keep the "competition" guessing - just my own personal opinion, nothing more. Procedures given in
papers seem much more reproducible.
Chemistry is life (and a whole lot more)
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vulture
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| Quote: |
You need at 350W PS which is available for the newer PCs. |
PC PSUs are available in ranges to atleast 1kW nowadays and perhaps even more. They tend to be somewhat expensive though and won't start up unless
they have proper ATX connection with a motherboard. So that would probably require some hotwiring. The upside is that for single rail PSUs you can get
80 amps at 12V.
One shouldn't accept or resort to the mutilation of science to appease the mentally impaired.
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len1
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Patent examiners are bound not to approve patents which they know, or have reasonable grounds to suspect, are false, misleading, or do not work.
Scientific publications also contain falsehoods - more so nowadays - in then past a scientists word indeed carried much weight than that of a patent
owner. Nowadays from my experience many papers published contain falsehoods. It is indeed the policy of many journals not to correct them. The
falsehoods are generally not at the level of out-and-out lies. More a case of youve done 10 experiments, 9 times didnt get anything publishable,
tenth you did. But cant reproduce it. So you publish it as a typical result.
I have not seen 1kW PSU on the market. At 12V they would be useless for electrolysis - at 5V they would be OK. But remember that many switch
supplies listing a 50A current mean a peak current beyond which protection circuits operate. The rectified supply I used provides a peak current
about pi/2 greater than the average value quoted.
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len1
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| Quote: |
The liquid Na wets almost anything including glass, which it attacks also, hence the black coating you can see. The coating - whose composition I dont
know, does not seem to conduct electricity, and once formed protects the glass, which was just superficially corroded. I would be interested to know
if you or anyone else has any references to this effect of liquid Na on glass. Using a metal tube to collect the Na (which you could also do in NaOH)
would overcome this, but it cant be used around the negative electrode.
Placing the -ve elctrode in the center of the tube has the Na wetting the tube, crawling around it, and being electrically connected to the -ve,
starts formation of globules outside the tube.
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I have now realised what the black stuff is - its Si. At 600C Na reduces SiO2 in glass
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Formula409
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| Quote: Originally posted by vulture | | Quote: |
You need at 350W PS which is available for the newer PCs. |
PC PSUs are available in ranges to atleast 1kW nowadays and perhaps even more. They tend to be somewhat expensive though and won't start up unless
they have proper ATX connection with a motherboard. So that would probably require some hotwiring. The upside is that for single rail PSUs you can get
80 amps at 12V. |
In order to start your typical compuer PSU, it's just a simple matter of grounding the green wire 
Good link here:
http://www.wikihow.com/Convert-a-Computer-ATX-Power-Supply-t...
Pinout of ATX connector:
http://notebook.arkane-systems.net/images/5/5a/Atx-power-sup...
I've been interested in making some Sodium for a very long time, however in Australia, I believe it is on the highest regulation list whereby
possession of a small amount such as 2g results in a massive sentence. Len can you comment on this?
Formula409.
[Edited on 11-7-2009 by Formula409]
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len1
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I think its deportation ..
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len1
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This is what I wrote a few months ago.
| Quote: |
Note however an interesting thing: Casnter's patent claims both Na and K, however the former is described in great detail - in particular the
temperature range 300-320 degrees is mentioned, while no such detail is given for K at all - when this happens you immediately suspect the author is
not terribly familiar with that particular process. I greatly suspect the following - Castner never produced any substantial amounts of K with his
method |
Now I found my suspicions shared by German researchers at the beginning of this century who attempted to 'repeat' Casners finding, stating bluntly
that he did not do what he said:
| Quote: |
Castner hat seine Versuche offenbar nur mit Natron-, jedenfalls nicht mit Kalischmelzen angestellt; wir halten nach unseren Erfahrungen fur
ausgeschlossen, dass Kalium aus reinem, geschmolzenem Kali nach dem Castnerschen Verfahren industriell hergestellt werden kann.
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Formatik
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Looks like a classical case of "if it works with A", it will (really an implied hope for should) 'also work with B, C, D, E, E ,F, J' that one
typically finds prodding around in the patent literature.
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franklyn
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Sodium by electrolysis through glass
From - 1926
http://etd.caltech.edu/etd/available/etd-11022004-131239/unr...
A remarkable paper , not so much for production of sodium , but for the
disclosure that glass normally thought of as an impermeable barrier can
serve as a membrane.
The scheme reveals that by using an ordinary lightbulb immersed in
molten sodium nitrate and the application of ordinary household electricity,
sodium is diffused into it and collects inside of the bulb.
A modest amount of perhaps a gram but sufficient for drying chemicals.
given lightbulbs are as cheap as they are this really bears investigating.
.
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S.C. Wack
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He had an article published a year before, mentioned in a JCE article [34, 289 (1957)] that I uploaded 5 years ago. A quote from it interested me, but
I never found the journal cited:
"The use of the hot filament of an incandescent vacuum electric light bulb in place of the cold cathode in a Geissler tube as a source of electrons
for combination with the mobile sodium ions from the glass, was first suggested by A. W. Hull of the General Electric Company. In 1925 R. C. Burt [J.
Opt. Soc. Amer., 11, 87 (1925)] used the Hull principle to produce commercially acceptable sodium photoelectric cells."
But 257 mg. does not sound commercially acceptable, for the production of sodium. But given another quote:
"Sodium ions from the fused salt electrolyte thus continuously replace those from the glass which have been reduced to atoms, and the weight of
metallic sodium obtained inside the evacuated glass bulb is proportional to the number of coulombs used.",
I have to wonder just how much sodium one can obtain from a single 100 watt bulb.
[Edited on 21-9-2009 by S.C. Wack]
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densest
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| Quote: Originally posted by S.C. Wack |
I have to wonder just how much sodium one can obtain from a single 100 watt bulb.
[Edited on 21-9-2009 by S.C. Wack] |
Assuming a mostly spherical bulb 10cm in diameter, with the filament centered, leaving 1/2 of the radius as space between the filament and the surface
of the sodium, pi*h2*(r-h/3) is about 82cm3 assuming r=5 and h=2.5. Also assuming the cheapest possible light bulb (but stock up, they're disappearing
soon!) it's maybe $0.70 for 60+g? The paper seemed to imply that it just kept coming through...
For the truly insane, one could string the filament from a quartz-halogen lamp inside a beta-alumina tube, seal & pump, dip in molten salts &
have a fine time... It's really sad that long fluorescent tubes have to have mercury in them because they have a -lot- of surface area.
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dann2
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Poasssium can be had via Potassium glass
Procedures in Experimental Physics (book) page 536 describes the process. A mixture of Sodium Nitrate and Nitrite are headed in an Iron tub with the
bulb in it.
The Sodium condenses up high on the bulb where a stream of cold air is blown onto it..........................
Potassium can be prepared by a similar method using K Nitrate and Nitrite and using Potassium glass.
Will copy and post later.
Where would one obtain Potassium glass? Make from fused quartz and K compound?
Dann2
Dann2
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chemoleo
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Cold air on Na condensation? How cold is cold?
Would be interesting to hear more!
Never Stop to Begin, and Never Begin to Stop...
Tolerance is good. But not with the intolerant! (Wilhelm Busch)
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