Electrolysis of sodium chloride

[Lance]

I have been trying to make Sodium metal by electrolysis of sodium chloride but I just can’t seem to get the salt to melt. I have been using a metal container over a Bunsen burner which should be hot enough to melt it. The melting point of NaCl is 800C. The underside of the container even turns red. Would this work better with a class beaker to keep the heat from sinking away? What temperature can the borosilicate beakers withstand?

 

I used "sea salt" because that’s all I had. Could this contribute to the problem? I figured impurities would just make the crystal structure weaker lowering the melting point.

 

Also As its heating the salt grains seem to explode as if there was pressurized gas trapped in them like pop rocks.

 

If I ever do get it melted would adding KCl lower the melting point of the mixture?

[Cap'n Refsmmat]

http://www.scienceforums.net/forums/showthread.php?t=5327

[Lance]

Hmmm... Well imagine that. I HAVE successfully melted it with a blow torch but the problem is the valve for the blowtorch has been converted to the valve for my burner so I can no longer use the torch. I don’t see why the burner would not melt it.

 

Also, fuel is dirt cheap here. The 13oz bottles of propane I'm using cost $3 each. Mapp gas is similarly priced.

[Lance]

Ok well I successfully melted the NaCl with a plumber’s torch. The salt glows red when it’s fully melted. I used 2 graphite pencil leads for electrodes. I charged them to 24v and the mixture bubbled and swirled a darker red. This also lowered the melting point as it mixed with the salt.

 

When it cooled it was a uniform metallic black. Whatever the product is it doesn’t look like sodium and it dissolved in water without making hydrogen. I’m thinking I didn’t apply the current ling enough and the product was still mostly salt with just a little bit of sodium. When the current was on I did get a big whiff of chlorine though. I definitely wouldn’t recommend doing this inside like I did. Anyway, a picture of the product it below on a napkin covered in mineral oil.

 

Well I suppose you guys saying you have never done it just made it more of a challenge.

 

If you want to try it your self plumber’s torches cost about $12 including a 13oz can of propane.

 

Edit: I’ll melt some more and take some pictures for those that are skeptical.

[Lance]

I used KCl this time because it doesn't explode and throw hot pieces of salt everywhere. The melting point is only slightly lower. I did this on a brick.

 

 

 

 

Edit: if the pictures dont show up then hit refresh

[Lance]

 

 

And I had to stop because the lead broke:

 

 

I still don’t understand why the sodium/potassium doesn’t create hydrogen when I put it in water... any ideas?

[YT2095]

it`s quite possible some metalic sodium did 3 thing, made a carbide with your rod, some recombined with the chlorine and some of it evaporated, as it BP is quite low.

 

you could do with trying it in the bottom of a baked bean can and use that as an electrode, and a single carbon rod as the other. the power applied is sufficient will be enough to keep the crystals molten without the need for the blowtorch after.

 

 

nice work and great pics though! )

[Primarygun]

How about burning an uranium ore?

What will be observed?

[Lance]

you could do with trying it in the bottom of a baked bean can and use that as an electrode' date=' and a single carbon rod as the other. the power applied is sufficient will be enough to keep the crystals molten without the need for the blowtorch after.

[/quote']

 

Hmmm... The first time I did it was On top of a can with the can as an electrode, but I was worried that the sodium would form a compound with whatever metal was in the can. (It was not steel can.)

 

Also you may be interested to know that because the melting point becomes so low, the heat of two carbon electrodes can keep it melted.

 

Edit:I just realized that’s exactly what you said and I even quoted where you said it.

[MulderMan]

is a plumbers blow torch the type that melts solder to seal pipes? also what type of battery did you use? a car battery. and is both the anode and diode both graphite? and wich does the sodium stick to as i thought you could only electrolise a liquid. is there a site which lays this out in detail as im interested in it. does it work with all salts?

[Lance]

is a plumbers blow torch the type that melts solder to seal pipes?

 

Yes. It’s the cheap and simple one. It’s just a tank, valve, and nozzle.

 

also what type of battery did you use? a car battery.

 

I used a 24V power supply. I don’t even remember where it came from. It’s current limited at 4A. It would be much faster if it could supply a higher current. A higher voltage will allow more current to flow, but a care batteries should work fine.

 

and is both the anode and diode both graphite?

 

I took two pencils and sharpened both ends of both pencils. I then hooked up my power supply to them one at a time and waited for the wood to burn off.

 

I think that this method is too impure though because they disintegrate quickly. I’m going to go the hardware store today and pickup a lantern battery and use the thick carbon rods in that instead.

 

and which does the sodium stick to as I thought you could only electrolise a liquid.

 

Sodium has a lower melting point then Sodium chloride so it mixes with the salt.

 

is there a site which lays this out in detail as im interested in it.

 

Not that I know of. I couldn’t find anything. As far as I know I'm a pioneer in the armature science community. If you find anything please let me know.

 

does it work with all salts?

 

I believe so but I would avoid the word "all" and replace it with most. I have only tried it with KCl and NaCl because they are so similar.

 

Of course I’m still having a problem with getting unwanted yields though. I have tried it with impure graphite, iron, aluminum, and some unknown metal and all have given the same results.

 

I’m thinking the problem may be that the current was not applied ling enough and its still mostly salt. But it should still release SOME bubbles of hydrogen in water.

 

Any input?

[budullewraagh]

some of it evaporated, as it BP is quite low.

just the prospect of Na(g) scares me. but come to think of it, it would be Na2O(g) and would cool quickly so i suppose it's not so bad

[Lance]

just the prospect of Na(g) scares me. but come to think of it, it would be Na2O(g) and would cool quickly so i suppose it's not so bad

 

 

So you think it would yield sodium oxide instead of pure sodium? Also I have been working with potassium more than sodium (not that it’s any safer). What color is sodium/potassium oxide?

 

Do they sell argon tanks at the hardware store? Maybe I could spray the sodium with Argon and heat it from the bottom. This is getting expensive.

 

Does anybody know how tungsten would react as the electrodes?

[AtomicMX]

Errrr btw, without a lab you would not be able to get Na(s) because it is quite reactive. it reacts with water, and if you are using store chemicals, in your process you would loose your Na(s). due the "diluidos" chemicals.

[AtomicMX]

"sea salt" It also cointains Magnesium salts and calsium salts. in a big amount.

[budullewraagh]

So you think it would yield sodium oxide instead of pure sodium?

if it yielded sodium gas, the sodium would instantly oxidize. personally i'm not so sure about the sodium boiling. if you want to test, check to see if there's fine black powder everywhere after you finish. that should be the sodium/potassium oxide.

 

i've never seen argon sold commercially, but then again i can't get anything around here. seriously, no chlorates, chlorites, perchlorates nitrates, phosphates, potassium compounds, halides (save HCl NaCl and NaF from tap water), sulfates (save MgSO4 and H2SO4 from car batteries)... the list continues.

 

as for your tungsten electrodes, i am not so sure. what do you mean by "react"?

[AtomicMX]

When making the electrolisis of NaCl you get in the cathode Cl2(g) and in the Anode H2(g) and in the pool you have and oxide far as i remmember.

[AtomicMX]

But remmeber NOT with a proper lab, the Na is very very reactive, and be carefull sodium makes a high explosion in contact with water.

[AtomicMX]

Tungsten would instantly burn out, melt, what ever.... its to bad metal conductor.

 

Thats why is you make a little hole in the crystals it burns.

[Lance]

Tungsten would instantly burn out' date=' melt, what ever.... its to bad metal conductor.

 

That’s why is you make a little hole in the crystals it burns.[/quote']

 

What?! Tungsten is extremely resistant to heat. They are used in arc wielders as electrodes so I don’t think Ill have problem with resistance. I just got back from the wielding store. Tungsten is also used in light bulbs…

 

And what holes in what crystals for what??

 

But remmeber NOT with a proper lab, the Na is very very reactive, and be carefull sodium makes a high explosion in contact with water.

 

You’re just making it more of a challenge.

[budullewraagh]

Errrr btw, without a lab you would not be able to get Na(s) because it is quite reactive.

he's wrong; people do electrolysis all the time and are successful. you have to be fast, however; molten sodium balls will fly out in random directions. you have to pick them up and throw them into an oil (preferably motor oil) as quickly as possible. chances are you will have an oxide layer on the outside of the pellets but you will have the metal inside. to fix this just scrape off the oxide while the pellet is submerged in the oil.

 

also, sodium doesn't react all that dangerously with water. depending on how much you add the sodium will fizz around the surface and hydrogen will be released. potassium has a similar effect but it is more vigorous and it burns in a purple flame.

to see a video of the reaction of K with H2O, go here:

http://www.webelements.com/webelements/elements/media/moov/K_H2O.mov

if you dont have quicktime just change the .mov to .mpg; they have both on their server.

 

of course, if you add the sodium to a concentrated acid, you will have a very dangerous and vigorous reaction.

[Lance]

Yes well it seems I’m still getting potassium oxide though. Sodium is commercially made in a downs cell where it’s never exposed to the air or chlorine. The electrodes are not the problem. I got the same yield with tungsten as carbon.

[AtomicMX]

What i mean is that in the outside is very difficult to obtain the metallic sodium, electrolisis can be done but you will not get sodium.

 

And i knew all what you said just that i am not particullary wrong.

 

But something that i may ask first, is why do you want metallic sodium for? i am is an army exclusive material. (supposed to be).

 

Tungsten is not resistant to heat, and it is used because it quickly burns.

Thats the idea of the light bulbs if you do not belive me make a little hole in a light bulb and turn it on.

[AtomicMX]

2 NaCl + 2 H2O = 2 NaOH + Cl2 + H2

[AtomicMX]

There is a way that you could get the sodium... perhaps using a Hg cathode Hg metls at 390' (Hg would make a ..... i do not know how its named in english "amalgama" and would protect the Na (ion) to mix with the water...

 

You may try that...