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Specialty Chemistry Forums => Citizen Chemist => Topic started by: Mr. Pink on March 31, 2005, 12:54:25 AM

Title: NaCl electrolosys
Post by: Mr. Pink on March 31, 2005, 12:54:25 AM
Hey, im wondering, what are the basics in the electrolosys for table salt? how is the sodium and chlorine collected? how do i prevent the Na from igniting? if you have to melt the NaCl to electrolize it, then if i cant use a Pt electrode, what should i use?
Title: Re:NaCl electrolosys
Post by: Mitch on March 31, 2005, 03:29:58 AM
"refined" graphite electrodes work fine. You can buy them on ebay.
Title: Re:NaCl electrolosys
Post by: jdurg on March 31, 2005, 03:36:02 PM
Do a quick search on google for the 'Down's Cell'.  There are plenty of sites which have very detailed explanations and diagrams of how molten sodium chloride is separated into sodium metal and chlorine gas.
Title: Re:NaCl electrolosys
Post by: Mitch on March 31, 2005, 04:59:25 PM
Then my opinion always is, "If you can't even spell electrolysis, you probably shouldn't do one." ;)
Title: Re:NaCl electrolosys
Post by: eugenedakin on March 31, 2005, 08:26:33 PM
Hello Mr. Pink,

When electrolysis is performed on an industrial scale, it is performed in a Chlor-Alkali plant.  Salt (as NaCl) is dissolved into water until it is saturated.  Then the salt-saturated-water is placed into a vessel with two electrodes (negatively charged, and positive charges).  The NaCl molecule separates to form Caustic Soda (Sodium Hydroxide) at one electrode and forms Chlorine gas at the other electrode.

Chlorine gas (very poisonous) is collected at one end, and sodium hydroxide is removed at the other end.

I hope this helps,

Eugene
Title: Re:NaCl electrolosys
Post by: Mr. Pink on March 31, 2005, 08:52:12 PM
Quote from: Mitch on March 31, 2005, 04:59:25 PM
Then my opinion always is, "If you can't even spell electrolysis, you probably shouldn't do one." ;)

Well, I never get good grades in Language Arts. But my dad is a jeweler and he does electroplating and electrolysis on a regular basis. He also has his bachelor's in Chemistry so I've learned a lot from him.

Title: Re:NaCl electrolosys
Post by: Mr. Pink on March 31, 2005, 08:55:20 PM
Quote from: eugenedakin on March 31, 2005, 08:26:33 PM

Chlorine gas (very poisonous) is collected at one end,


Don't worry, i know whats safe and whats not. Anyone who doesnt know that chlorine is poisonous (i dont think i spelt that right either, or the word "either") shouldn't be in chemistry or even a WWI historian.
Title: Re:NaCl electrolosys
Post by: jdurg on April 01, 2005, 11:56:19 AM
Also, you absolutely cannot obtain sodium metal from the electrolysis of aqueous NaCl.
Title: Re:NaCl electrolosys
Post by: Mr. Pink on April 01, 2005, 02:21:15 PM
Quote from: jdurg on April 01, 2005, 11:56:19 AM
Also, you absolutely cannot obtain sodium metal from the electrolysis of aqueous NaCl.

Ah, thank you, thats what i wanted to know.
Title: Re:NaCl electrolosys
Post by: Viper3k on April 01, 2005, 10:46:37 PM
I did this exact electrolysis on aqueous NaCl.

The gases were released and after a few hours there was a brown sediment forming and a sort of greeny layer on top. I have no idea what they were.
Also, could you use carbon rods taken from alkaline batteries for electrodes?
Title: Re:NaCl electrolosys
Post by: Mitch on April 01, 2005, 11:25:02 PM
don't know.
Title: Re:NaCl electrolosys
Post by: Mr. Pink on April 04, 2005, 06:50:56 PM
::Edit:: The synthesis of explosives is not appropriate material here.

Well, i wasnt planning on using it as an explosive; my personal objective is to collect all (or at least the more common) of the elements in thier pure form. Do you think that i would be responsible enuf to put the detailed warnings at the bottom, but not responsible enough to keep the sodium from exploding?
Title: Re:NaCl electrolosys
Post by: Garneck on April 09, 2005, 06:15:35 PM
Quote from: jdurg on April 01, 2005, 11:56:19 AM
Also, you absolutely cannot obtain sodium metal from the electrolysis of aqueous NaCl.

Of course, you can only get hydrogen.

But, hmmm, what about if you use a mercury electrode? I always thought you can get NaOH during that.. correct me if I'm wrong.
Title: Re:NaCl electrolosys
Post by: Mitch on April 09, 2005, 07:32:40 PM
Quote
Do you think that i would be responsible enuf to put the detailed warnings at the bottom, but not responsible enough to keep the sodium from exploding?

Spelling and grammar aside, that's not the point.
Title: Re:NaCl electrolosys
Post by: lordofdarkness on June 22, 2005, 05:47:54 AM
Helloz
I done this b4
I was successful
I made my own downcell and melted salt using and oxy acetyline welders flame
I got enough sodium 2 make fireworks!!!!!
Title: Re:NaCl electrolosys
Post by: hmx9123 on June 22, 2005, 07:15:55 AM
Fireworks don't use elemental sodium.   ::)  Elemental sodium simply reacts with water, an interesting reaction, but not a firework.
Title: Re:NaCl electrolosys
Post by: lordofdarkness on June 22, 2005, 07:18:31 AM
I used it as a expression
Made a light show and sparks
and a nice smoke ring
Title: Re:NaCl electrolosys
Post by: Grumples on June 22, 2005, 09:11:55 PM
If you're trying to make elemental sodium, I'd suggest not doing it.  Firstly, the melting point of NaCl is 800 degrees celsius.  Good luck getting your cell that hot.  Not only is that a logistical problem,  I'd be willing to bet that that is well over sodium's auto-ignition temperature, so it has to be sealed off from any air (as well as the created Cl2 gas, of course).  Finally, to actually have any fun with it (that's what you're aiming for, right? ;) ) you'd have to produce a rather considerable amount (about 100 g is necessary to make an explosion, according to Theodore Gray).

There's a reason elemental sodium is not cheap as dirt.

If you want something that will ignite in contact with water, there are several other possibilities, which I'm sure you can find online somewhere.  they are significantly safer, have materials which are easier to aquire, and will run a significantly smaller chance of killing everyone in a three block radius.  (liquid sodium in a confined space at 800o C? bad idea)
Title: Re:NaCl electrolosys
Post by: jdurg on June 22, 2005, 09:41:43 PM
Quote from: Grumples on June 22, 2005, 09:11:55 PM
Finally, to actually have any fun with it (that's what you're aiming for, right? ;) ) you'd have to produce a rather considerable amount (about 100 g is necessary to make an explosion, according to Theodore Gray).

I think you have misunderstood Mr. Gray.  Sodium is incredibly not dense, and 100 grams of it would be a chunk about 2.75 square inches.  That's a VERY large amount.  To get an 'explosion' where the sodium metal and hydrogen gas ignite, you need a chunk about the size of your thumb.  Otherwise, it will just pop quite loudly and won't really produce a dramatic 'kaboom'.
Title: Re:NaCl electrolosys
Post by: P-man on June 23, 2005, 04:26:42 PM
Yeah, I know the one where you put a chunk of sodium with water, and ooolalaaaa. But i haven't heard the one with hydrogen.

Why would the larger amount of sodium NOT explode while the lesser amount of sodium explode??

Pierre
Title: Re:NaCl electrolosys
Post by: jdurg on June 24, 2005, 03:34:29 PM
Okay, that was just some piss-poor grammar on my part.  First of all, the size of a 100 gram chunk is 2.75"x2.75"x2.75" and not 2.75 square inches.  So imagine a lump about the size of a billiard ball.  As for the explosion, you need a chunk at LEAST the size of your thumb in order to get an explosion.  Anything LESS than that size really won't explode.  Anything MORE will definitely explode.  I just worded my post incredibly poorly.
Title: Re:NaCl electrolosys
Post by: P-man on June 28, 2005, 11:11:33 AM
Got it.
Title: Re:NaCl electrolosys
Post by: Agent-X on July 16, 2005, 10:23:22 PM
Can't you get sodium from heating up NaCl in a plate up to about 800 celcius or w/e while using carbon rods to seperate the material. I'm into watching explosives and crap  :o :o I can understand if you guys don't want to talk about that here. It's still fun though.  :1eye:

Basically you can take sodium away from the NaCl, you will have chlorine gas go off also.

The thing that becomes a problem is the part of keeping the sodium dry. I think that's what the down's cell is about right?

I've never did the studying to figure out the extraction of Na from NaOH. I'm thinking it would be less dangerous to do than the NaCl because you don't have chlorine gas trying to kill you.

Perhaps you could use the same carbon electrode method to take out the O and H since both of them break up when electrolyzing water.

You're going to have to keep the sodium dry either way you look at it, or else the sodium will explode on you and it will all be pointless. That's the thing about trying to extract things during a chemical reaction, time becomes a giant factor.

Picture of Downs Cell:
(https://www.chemicalforums.com/proxy.php?request=http%3A%2F%2Fwww.sciencemadness.org%2Fscipics%2Fdowns_sodium_productioncell.jpg&hash=67e2ae0eb031c1df9f07f9e99964e39bad98573f)

Of course you will have to somehow guide the flow of chlorine away and also guide the Sodium(l) (Na)

Quote
Hmmm!

listen guys, I had a thought. I am certain that our esteemed progenitors have given a great deal of "energia cogentis"
to the vexing issue of sodium production, while the organic chemists creed is to avoid ultra-high temperatures at all costs, perhaps we are unneccesarily complicating the obvious here.


The DOWNS cell is an apparatus equaled in its sophistication only by its simplicity.

Using the NaCl version seems a little foolhardy and expensive until you factor in the ruggedness and ease of manufacure. And the common availability of materials procurement.

and the skills and techniques learned in the course would be invaluable in future endeavors

Perhaps Cl gas is fairly reactive, but not unnaturaly dangerous as long as you were careful to use good, robust gas-tight fittings.

And I KNOW that your collective genius can come up with oodles of uses for the Cl that is evolved.....HMMMM?
source: Science Madness (http://sciencemadness.org/talk/viewthread.php?tid=2103&page=2)

That's just a bit of information. You could probably find more on this elsewhere.
Title: Re:NaCl electrolosys
Post by: jdurg on July 18, 2005, 02:06:02 PM
You also need to make sure that the liquid sodium isn't exposed to any oxygen, or any other oxidizing material.  At the temperature required for the electrolysis, the sodium will be in a very molten form and highly susceptable to reaction with water vapor, oxygen gas, any halogens, any nitrogen oxides, etc.  The reaction chamber absolutely MUST be free of oxidizing gases othewise a very nasty explosion will occur.
Title: Re:NaCl electrolosys
Post by: Agent-X on July 19, 2005, 05:06:42 PM
Did someone remove my picture?  ???
Not nice...

Anyways, a good way to raise the temperature if you're attempting to conceal the sodium away from other material that will set it off, is to heat up the down's cell or else crucible with thermite.
Title: Re:NaCl electrolosys
Post by: soroka69 on September 21, 2005, 12:51:03 PM
Hello every one. I’m thinking if some one need metal sodium is it better to melt a sodium hydroxide, it melts at a lot lower temperature, les then 400C. I have Downs Cell made from clay-graphite crucible number #35 and cover is also graphite with a upside down Y as a duct with a hole all the way to the outside  with ¾ steel pipe extension, cathode is thick ring of steel, anode is graphite that resembles Y it has vertical channels in the top side of the Y. In the side wall of graphite crucible 2/3 from the bottom is a ½” diameter steel pipe that is 9” long (protrude true the wall of the furnace) with steel valve on the end. Cathode is connected to it. I fill the crucible 4/5 full; if I drew sodium metal I add more salt to the crucible. And all this is inside of 55 gallon dram – the furnace. I use a lot of refractory material to keep the heat in. Use a 20. Lb BBQ tank as a fuel cell and 0-12 PSL gas regulator. I can melt aluminum and brass in that furnace like a foundry. The inside temperature is ~ 1000C. To evacuate chlorine I use argon gas. Do not use argon+CO2 mixture! Sodium burns in CO2 presence!  For electric power I use car battery charger 150 Amps 12Volts. Sold in auto stores for $139.00 to $189.00 . And if you have an extra car battery put in parallel to the charger the higher current flow the better.  I hope this help, if some one makes this and get hurt by it please keep me from the lawsuit.  ::)
Title: Re:NaCl electrolosys
Post by: jdurg on September 21, 2005, 07:41:20 PM
Sounds like a nice setup.  You'll have to take some photos of it and your end product.   ;D
Title: Re:NaCl electrolosys
Post by: soroka69 on November 11, 2005, 12:00:59 PM
I’m working on the blueprint for smaller version of my apparatus. Made from old propane tank as a Downs cell and a 35 Gallon dram Foundry. It will be more portable, for all you people. Small problem that you have to supply an 110Volts at 20Amps for long time, also you going to need a couple 12 Volt high current batteries in parallel. Got to have current to do the job writhe. More current you can provide, more sodium will separate from chlorine in the Downs cell. The project is complicated, requires welders skill, and some drilling. All shove you haw to calculate your transformer and get a set off high current diodes. This is simple but… What to do with Chlorine gas?  And you are going to get an Argon tank to flash chlorine gas from the electrolysis chamber. You ask me where to - your idea. In my set up –to the water solution of baking soda. All my next posting will accommodate the picture in progress.  I will explain later why a lot of current is important for this setup.  I hope this help, if some one makes this and get hurt by it please keep me from the lawsuit.            
Title: Re:NaCl electrolosys
Post by: soroka69 on November 11, 2005, 12:19:31 PM
Hello jdurg. Final product has to be purified. I’m getting80% sodium 20% salt from my setup. It has to be reheated in the reparatory funnels. Sodium on the top and salt is on the bottom of the funnel. I hope this help, if some one makes this and get hurt by it please keep me from the lawsuit.  
   
Title: Re:NaCl electrolosys
Post by: hydrowire on November 13, 2005, 12:19:04 AM
Sodium is very dangerous.

Few days ago I 'took' a piece of Na from my skul chem lab about the size of two thumbs and throw it in a puddle of water under a tree. Then we watch as it reacts with water vigorously.

5~10 seconds later..BOOM! We are so frighten and walk away. We don't run because we might look suspicious. The sound is as loud as firecrackers. We are glad no one hurts.

No more Na experimenting next time..
Title: Re:NaCl electrolosys
Post by: constant thinker on November 13, 2005, 09:06:58 PM
I've always wanted to try the old throw sodium in water thing. Let's hear some stories or maybe a movie or 2 if somebody ever does.

I'd think that NaOH would be easier to seperate also. Just because from what I've been told and read the Halogens usually form strong bonds.
Title: Re:NaCl electrolosys
Post by: jdurg on November 14, 2005, 11:30:17 AM
Just take a look through the forums here for my post about my trip up to New Hampshire.  I went up to a cabin on a lake in NH and took some sodium metal with me.  Took a few pictures of the explosions.  When you throw a nice sized lump into water, there is a substantial delay as the metal reacts with the water.  You hear a lot of hissing and fizzing and you start to get kind of nervous because you know it's going to explode, but you don't know when.  When it finally does detonate, it's like the sound of a 12-gauge shotgun going off and a bright orange fireball goes up in the air followed by a mushroom cloud of NaOH smoke.  If the metal hasn't completely disintegrated from the heat of the explosion, small little chunks of Na will fall down onto the water and fizz and pop for a while.  The explosion is VERY unpredictable which is what makes it a bit dangerous.
Title: Re:NaCl electrolosys
Post by: jdurg on November 14, 2005, 11:32:07 AM
Take a look here.  You can see the tail end of a daytime detonation and a night time explosion. (http://www.chemicalforums.com/index.php?board=9;action=display;threadid=4058)