Sodium from Salt?

[1145climber]

Hey all. First post! Looks like a cool forum board, happy to be here. Anyway...

 

ive been wondering, is it possible to obtain pure sodium from table salt (nacl)? the process ive been researching includes melting the table salt in a pan until it starts to melt. Then, electricity is applied to it in an electrolysis-like manner through 2 electrodes (copper? carbon?). At the negative electrode, sodium will gather, and at the positive electrode, chlorine should be given off as a gas (obviously shouldnt be breathed).

 

so is this a plausible process? I am a high school student, and am new at this (chemistry) but im really interested in learning more, so i would appreciate any comments. and yes, i am aware of all the implications of salt and the cautions that should be used around it... we have experimented with it in school. so? any comments? thanks. - adam.

[BenSon]

Welcome I'm new here myself....

NaCl is hard to electrolyse straight because its so hot when it melts to sodium will evaporate instead of being a liquid. I was thinking of doing this myself with some K/Na salts. Their hydroxides have much lower melting point 380C and 322C respectively and you wont have to deal with Cl2 gas. Your metals will also react readily with the atmosphere more so at those temperatures so an inert atmosphere is a good idea it was sugested to me to use Argon don't know if thats easy for you to get? Anyway i hope that helps good luck to ya

 

~Scott

[jdurg]

The industrial process for sodium generation involves the electrolysis of a molten NaCl/CaCl2 mixture. The calcium chloride lowers the temperature needed to melt the salt so that electrolysis can be performed. The anode and cathode are isolated from each other as well because you do NOT want molten sodium metal reacting with chlorine gas. That is incredibly dangerous.

 

For the small scale, using the anhydrous, molten hydroxides is the better method. However, keep in mind that the hydroxides will readily absorb water from the air and carbon dioxide as well. This can have serious implications on the electrolysis products. (I believe that sodium bicarbonate has a much higher melting point than sodium hydroxide does). Also, sodium hydroxide is extremely corrosive in a molten state. Not only would you get severe thermal burns if it contacted your skin, but severe chemical burns would result as well. (Accelerated in reactivity, might I add, due to the increased temperature). Platinum electrodes are optimal when doing this, but carbon electrodes may work too. You want to avoid things like copper, zinc, etc. since they are fairly reactive and might lead to some nasty side reactions. (I'm not 100% sure of this because I have never done this myself. Only a LOT of research on the process which afterward made me decide to just buy the damned metal instead of making it. ) So it can be done, but it's not an easy 'baking soda + vinegar' process. A good deal of equipment needs to be used and numerous safety precautions as well. An inert atmosphere is also an absolute requirement so you'll have to get yourself a nice big tank of argon to bathe the electrolysis setup as well. While it's fantastic that you have this strong interest in chemistry, it is vitally crucial to do copious amounts of research before getting started on anything like this. Even one mis-step or overlooked 'danger' can result in serious injury.

[Lance]

I tried this and came to the conclusion that it is impossible without an inert environment.

 

Try searching for other threads.

[jdurg]

The problem with sodium hydroxide electrolysis is that in addition to making sodium metal, you also make oxygen gas and water. That's not good. You would need a good deal of NaOH in order to make sure that the anode and cathode are far enough apart to prevent mixing of the electrolysis products. For the oxygen problem, you could always seal off the molten NaOH and just draw out the oxygen by putting the electrode in a cylindrical outlet and either draw a slight vacuum to pull out the O2 or burn the O2 as it is coming out. Still, it's not an easy setup.

[ed84c]

Use Carbon anodes and the O2 will form CO2 instead.

[raivo]

Use Carbon anodes and the O2 will form CO2 instead.

 

and CO2 will react immediately with NaOH to make Na2CO3 + H2O.

 

Stainless steel and carbon are fairly stable in molten NaOH and KOH environment. So electrodes are not problem. Much harder is to find something that can be used to separate anode and cathode areas. Some separation makes things a lot more realistic but only suitable electrical isolator i know is asbestos. Later is dangerous for health and rather hard to find nowadays. Glass will dissolve immediately and teflon reacts violently with liquid Na.

[1145climber]

cool.... so i guess this process isnt as simple as i hoped.... is there no other process, maybe an easier one, to get sodium through methods other than electrolysis??

 

but anyway, i liked jdurgs's analogy:

 

"So it can be done, but it's not an easy 'baking soda + vinegar' process"... lol

 

while we're on the topic, are there any "baking soda and vinegar" experiments that i could do, even totally unrelated to sodium, just so that i could learn more about chemistry and get more experience?

[Lance]

=.... is there no other process' date=' maybe an easier one, to get sodium through methods other than electrolysis??

[/quote']

 

Yes, Its called 'ebay'.

[budullewraagh]

high temperature reduction of sodium salts with fine magnesium or aluminum powder works, but you can't do it, i promise.

 

electrolysis isnt all that hard. really. just put a blowtorch to some NaOH, hook up a car battery and start catching the molten balls of sodium. if you want a more pure product (less oxidation), do it under argon. you can put together a reaction vessel that will remove the gaseous products and still keep argon over the reactant.

[jdurg]

....and if the slightest bit of water gets into/onto your molten sodium, you have an explosion which will send molten NaOH and other caustic chemicals all over the place. You also need to make sure that your inert blanket of argon isn't going to extinguish the flame on your blowtorch. There are a lot of things that still need to be kept in mind when doing this, and thinking that you're going to get ounces of sodium metal is very unlikely.

 

Now for the question about 'other neat experiments', there are a few that can be done. You can take some lye and make a concentrated solution out of it, then put some aluminum foil in there. The foil will slowly start to bubble and give off hydrogen gas. After a while, the bubbles will start coming off more vigorously and pretty soon you'll have a good amount of hydrogen gas. Another neat one you could do, although it is quite a bit more dangerous than the aluminum + NaOH one, is generate chlorine gas and use it to make some iodine or bromine. If you really want to do that one, let me know and I'll try and guide you in the right direction. Making chlorine is pretty easy, and once you've got chlorine you can use NaBr to make some bromine. Then you could possibly take the bromine and put some aluminum foil in there and GET THE HELL AWAY FROM IT! It's a pretty interesting experiment. Again, however, extreme caution must be taken when handling any of the halogens as they are all fairly toxic and reactive.

[budullewraagh]

except iodine.

 

you may want to make some iodine. it's fun. bromine is a bit scary though, so i don't suggest you make it, only because it's somewhat difficult to contain and very volatile. i find it to be significantly more dangerous than chlorine.

[1145climber]

Yes, Its called 'ebay'.

 

hahahahhaha, yeah. but i was looking for some scientific educational value in it.... wow, never thought i'd say that.

 

and the making of chlorine, and then turning it into iodine sounds aright... can i get some more info on that?

[budullewraagh]

see image:

add the HCl to the NaOCl/Ca(OCl)2 and put the funnel down immediately. the u-tube should be under the surface of the iodide solution. make the iodide solution relatively concentrated. also, it should be noted that it's a good idea to get a way to hold the u-tube under the surface of the iodide; otherwise the pressure may cause the end of the u-tube to rise above the solution. make sure you get a good stoichiometric lot more chlorine than iodide, as if there is iodide, it will dissolve the iodine.

 

when the reaction is done, take your wet iodine and dry it. a good way to do this is to pour off the water (quickly because the iodine sublimes), then put the iodine crystals in a closed tube and have it evaporate and pass over some CaCl2 or if you're so fortunate to have some, Mg(ClO4)2, before solidifying in a cooled area of your apparatus.

[BenSon]

You can take some lye and make a concentrated solution out of it, then put some aluminum foil in there. The foil will slowly start to bubble and give off hydrogen gas. After a while, the bubbles will start coming off more vigorously and pretty soon you'll have a good amount of hydrogen gas.

 

Its also fun to ignite the hydrogen gas with oxygen to make water, don't ignite too much at once before you've done it with small amounts to get the idea of how much it burns.

 

~Scott

[langstonwf2]

which will turn sodium hydroxide into sodium bicabonate

[YT2095]

which will turn sodium hydroxide into sodium bicabonate

 

what will dude?

[hermanntrude]

Advice to anyone who wants to make halogens or group I metals:

 

Look up the MSDS of all the relevant materials BEFORE you start. MSDS are easily found by googling. They are very revealing documents.

 

example:

 

MSDS for chlorine

[langstonwf2]

what will dude?

adding co2

[YT2095]

erm... you`v completely lost me here?

 

can you place it in Context please, it just seems like a random comment else

[Cap'n Refsmmat]

From what I gather, he's saying that adding CO2 will turn your sodium hydroxide into sodium bicarbonate.

[YT2095]

it will yes, but the relevance here is my point of confusion.

[nitric]

it'll also produce water

Edited June 19, 2008 by nitric