UncleJoe1985
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want transparent container for molten NaOH
I'd like to give making sodium metal from NaOH electrolysis a shot.
Obviously, a regular glass container is out of the question, so I'm planning on using porcelain. But being able to see the process is as desirable as
making mushroom clouds 
What if I coat part of the inner glass? Are there any films that can withstand molten NaOH? I thought about PTFE, but that doesn't sound very feasible
since it melts at 326.8°C, while NaOH melts at 318C. Plus, I don't even know if Teflon will stick to glass when melted.
Any other suggestions?
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BromicAcid
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Pretty sure porcelain isn't an option anyway. Neither is PTFE, NaOH will eat that as well. Usually these cells are constructed from nickel or iron
(read the sodium thread). The best you're going to be able to do is put a window in the top of the cell and even then it's going to likely cloud up
on you before long.
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DrMario
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Maybe fused silica - though fused NaOH will attack it.
Bear in mind that alumina crucibles would be much better than fused silica ones, but they are opaque (non-transparent). The fused silica crucible
should survive long enough.
[Edited on 18-1-2015 by DrMario]
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Metacelsus
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What about beryllia? Alumina and silica will react; I don't think beryllia will, or if it does, it will be much slower. That being said, beryllia
crucibles are not exactly cheap, and may not be sufficiently transparent.
Magnesia might also work, and it is probably cheaper.
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UncleJoe1985
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Thanks everyone for the comments and references. My goal is to make a cell that doesn't corroded quickly nor make chocolate pudding like this guy. I'm really impressed by len1's design (hats off to him), but I want something smaller, and maybe simpler. It said it took 2 hours to go from 20 - 360 degrees for 1.5 Kg
electrolyte and a 500W hotplate, which seems excessive. Theoretically, it ought to take only 26 minutes. I think by not using a metal container and
putting the nichrome heating element in the electrolyte itself will make it more efficient.
| Quote: | | Pretty sure porcelain isn't an option anyway |
Oh right, because porcelain has glass in it! Also, this guy says molten NaOH will attack the glaze on porcelain slowly.
| Quote: |
Magnesia might also work, and it is probably cheaper.
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That looks promising (garage chemist from len1's thread also said it won't be attacked). I'd like to try powder coating glass with it.
I don't want to try this unless the etching is 100x slower than for regular glass.
I am curious why the removal of soda causes it to be more resistant? Is it because NaOH, Na2O, and CaO are ionic molocues and likes dissolve likes?
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UncleJoe1985
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Alternative electrolytic methods for producing sodium metal?
After lots of studying of the home-scale friendly method of sodium production by NaOH electrolysis, it seems a bit difficult due to the corrosion and
need for temperature/process control to prevent contamination or dissolution of the produced metal. After all, I want to produce sodium, not chocolate pudding...
It doesn't seem high temperature reduction (e.g. Na2CO3 + 2 C → 2 Na + 3 CO) is easy or inexpensive, so are there other electrolytic methods? I
thinking of,
1. solvent that can dissolve NaCl or other similar salt without reacting with Na?
It's clear ethanol and methanol will react. According to Wikipedia, NaCl can dissolve in acetone but with a solubility almost 1/1000000 that of water.
Is it possible to bring to bear high voltage and some high temperature to make it work?
Or can it be proven that no such solvent exists? (e.g. NaCl will only dissolve in polar substances, but polar substances easily ionize, which will
react with Na?)
2. Electrolysis of molten NaCl or other salts?
Has anyone tried this and know how feasible it is? Will nichrome wire be sufficient to melt it? Are there decomposition or dissolution issues like
with the NaOH process?
I'm also thinking about salts with lower melting points. Sodium bromide melts a bit easier and more so with sodium iodide. Can anyone hook me up with
some sodium. Anyone can hook me up with some sodium astatide
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Metacelsus
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DO some research:
1) Propylene carbonate
2) Downs cell
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Bert
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Threads Merged
19-1-2015 at 16:25 |
Bert
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Thread Moved
19-1-2015 at 16:26 |
vmelkon
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Propanone dissolves NaI and KI. Perhaps you can try to electrolyse this but I have a feeling that it won't work. I'm sure that Na or K will react with
the carbonyl group.
Signature ==== Is this my youtube page? https://www.youtube.com/watch?v=tA5PYtul5aU
We must attach the electrodes of knowledge to the nipples of ignorance and give a few good jolts.
Yes my evolutionary friends. We are all homos here. |
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Zyklon-A
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Check out this thread, all about electrolysis in a non reactive solvent, mostly propylene carbonate.
I can sell you some sodium bromide, no iodide though. See the link in my signature.
Sodium reduction with carbon is only useful at about 1200 deg. C and under strong vacuum, if you can manage that, it may be possible, but yields will
suck even in the best of conditions.
There's quite a lot of information on electrolysis of fused sodium chloride on this site and many others, some people here have tried it IIRC.
Magnesium can reduce sodium hydroxide easily, so can aluminum.
Under high vacuum at 600 deg. C magnesium can even reduce sodium chloride, but yield will not be great. Aluminum won't work for this.
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UncleJoe1985
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I can't find anyone else's experience on this on this site, so that's why I asked. I'm worried that the higher temperatures involved will make
contamination even a bigger problem than for the NaOH process.
| Quote: | | Propylene carbonate |
Incredible! so such a solvent does exist.
Zyklon: How did your experiment with PC go? You kind of trailed off after 4/2014. I just read the 1975 article by Jorne and Tobias. I understand your
logic for using NaClO3, since that's much more soluble than NaCl (at least in water) and easier to get than NaClO4. But if it can break down (in
solution) and release O2, then that would be bad.
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deltaH
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Sodium (being a rather good reductant) would probably reduce chlorate (being a rather good oxidant) if such a cell ever produces sodium at the cathode
in the first place 
[Edited on 20-1-2015 by deltaH]
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Zyklon-A
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Yeah, if sodium chloride is even a little soluble (like 2 grams/100mL) I would use that as it is more likely to work with oxidizing it again.
My PC never came, I got scammed. I was planning to buy some more, but since then I've gotten a good vacuum pump and have welded a setup to distill
sodium from NaCl and Ca or Mg. I was going to do it over Christmas break, but I had a lab accident that redered both hands unmovable for a week or so,
then I sprained an ankle and still can't walk so I just haven't been able to try it yet.
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hyfalcon
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"Solar Salt", see wiki.
http://en.wikipedia.org/wiki/Eutectic_system
Looks viable if you can cope with the NOx.
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deltaH
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Ouch ZB! Hope it get's better soon.
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Zyklon-A
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Another idea utilizing an eutectic salt mixture is KAlCl4.
It has a very low melting point (I think around 300°C). It's hard to make and it's not stable in air, due to the aluminum chloride being a mostly
covalent compound, which reacts with water.
It's covalent properties are what makes it useful for electrolysis as it lowers KCl's MP but doesn't decompose with electrolysis.
It seems to me that potassium would react with aluminum chloride though, but I haven't heard or seen it do that.
| Quote: |
Ouch ZB! Hope it get's better soon.
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I should be able to walk in a week or so, my hands are fine and all the stitches are out.
[Edited on 20-1-2015 by Zyklon-A]
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UncleJoe1985
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| Quote: | | I had a lab accident... |
You sound pretty hard core. What energetic material were you playing with? TNT? NH4NO3?, nano thermite? Any lessons to share?
Scamed by a chemical seller? I find that pretty hard to believe because I doubt a crook who probably dropped out of high school would know much about
chemistry. Did you order from a reputable company or did you order some surplus from a Chinese company that was watered down (I wouldn't mind 5%
impurity since the 99% reagent grade stuff is way more expensive)?
Do you know how I can make KAlCl4 or buy it?
It seems AlCl3 would be a precursor, which even has a lower melting point of 192c, but wouldn't be suitable for Na production since Al has
a lower electrode potential?
That seems almost as undesirable as using molten NaClO3 since it decomposes to release O2, oxidizing the sodium.
[Edited on 20-1-2015 by UncleJoe1985]
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Zyklon-A
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Buying is hardly an option, it's very expensive. It can be made from fusing KCl and AlCl3 at 700°C.
AlCl3 boils before it melts, so it's not easy to do, high pressure is required. It can be made by reacting aluminum with chlorine or
hydrogen chloride anhydrous.
| Quote: |
but wouldn't be suitable for Na production since Al has a lower electrode potential? |
That's what I'm not sure of, like I said, it's covalent, and doesn't decompose by electrolysis, but seems like sodium, or potassium would reduce if
after they're isolated, but since I've never confirmed this, and I have heard it does work, I'm going to assume it does.
| Quote: |
What energetic material were you playing with? |
I don't screw with energetic materials anymore, although I've never had an accident with them. It was just a flammable gas mixed with oxygen, wasn't
supposed to ignite, but somehow it did. The biggest loss was the flask and the 5 or so beakers/flasks next to it, and a GoPro case, good thing it was
in the case...
| Quote: |
Scamed by a chemical seller?
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Perhaps not scammed, but the money left my account, and the product never came, maybe a mistake.
[Edited on 20-1-2015 by Zyklon-A]
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