Electrolize NaCl into Chlorine and Sodium with Fresnel Lens

[NightHawkInLight]

The thread title about sums up what I want to try for an upcoming project. I would like to use some sort of crucible under a large fresnel lens to heat table salt to its melting point and then using an anode and cathode of perhaps titanium, reduce NaCl to its base elements. I plan on using a dye of some sort to darken the salt and make it more receptive to the heat.

 

Is this another one of my crazy and impossible chemistry dreams, or could it be done?

 

I couldn't find much by searching for the process by which NaCl is electrolyzed, only that it's done. I have a few questions for you chem geniuses out there: (1) Would sodium be too reactive at such a high temperature to end up with any sizable amount at the end of the experiment? (2) Would Ti be a good anode and cathode choice, or would it react badly with the chlorine? (3) Would a specific current be necessary, or would just about any do - such as that from a battery charger?

 

And of course, is it even possible?

 

I appreciate any feedback. Dash my ideas to bits if you must, I know they're often nuts.

 

-NH

[Ralph]

in industry it is often done with natural gas or coal (depending on location and availability it is possible with almost any currentthough it will take longer (just like chlorate production) carbon will work and is sometimes used in industry though the preferred electrodes are an iron cathode and a graphite anode i think adding a dye and using solar energy may not be your best option for 2 major reasons we would see this in industry (as the aim is always to use less energy) and the dye is likely to react with either the sodium or the chlorine or decompose at temperatures though very fine charcoal could feasibly be used it would give a low purity product are you looking to produce sodium or chlorine if chlorine is your by product do not waste it bubble it though a solution of potassium hydroxide as this will create hypoclorite which is created in the first stage of chlorate production and will mean you will use less time and energy to produce chlorate

[NightHawkInLight]

in industry it is often done with natural gas or coal (depending on location and availability it is possible with almost any currentthough it will take longer (just like chlorate production) carbon will work and is sometimes used in industry though the preferred electrodes are an iron cathode and a graphite anode i think adding a dye and using solar energy may not be your best option for 2 major reasons we would see this in industry (as the aim is always to use less energy) and the dye is likely to react with either the sodium or the chlorine or decompose at temperatures though very fine charcoal could feasibly be used it would give a low purity product are you looking to produce sodium or chlorine if chlorine is your by product do not waste it bubble it though a solution of potassium hydroxide as this will create hypoclorite which is created in the first stage of chlorate production and will mean you will use less time and energy to produce chlorate

 

Thanks for your reply, very useful!

 

There are simpler ways to produce chlorine, so yes, my goal is to produce sodium. Through the years I have still not gotten around to chlorate production, so I'll discard the chlorine for now.

 

I do not particularly need a pure product, and charcoal was the primary 'dye' I was considering. I chose the fresnel lens energy source mostly because I just acquired a very large one. I suppose if the temperature of 800 something Celsius can be easily enough maintained with coal in a chimney I will likely end up using that. It would certainly simplify the setup.

[Ralph]

dont discard the the chlorine its bad for the environment and bad for chemical engineers they wont be able to sleep at night with the knowledge you are discarding such an energy expensive gas.

 

chlorate production is quite easy and very cheap (KCl can be purchased for around $5 au dollars per kilo) any way if you choose not to use the chlorine (im sure you already know) but vent it away from flammable things are it is a powerful oxidising agent i would recomend having a cell in the following design (sorry for the poor quality but i made it in paint) to prevent the sodium and chlorine re reacting hope this is large enough to read the text and all

[rocket]

I’ve made sodium (tiny amounts) a couple of times using electrolysis, I used NaOH though as its melting point is rather low (323) and the heat from electrolysis will keep a localized area molten. The best metals to use are iron for the cathode and copper or nickel (the best) for anodes.

 

Just got to watch out for the oxygen and hydrogen that forms, it tend to ignite and through molten NaOH around.

[Ralph]

hense why you use sodium chloride it is safer and results in a purer product

[a_bab]

I know that a large fresnel lens is able to melt a coin for example, but the focal point is concentrated in a size siimilar to a coin. For melting NaCl I'd try to get a graphite crucible that would absob the light energy in an eficient way. Also, you need welding glasses unless you want to be blinded, but I think you already know this as you must have played with your lens quite alot.

[Ralph]

a phphite crucuible wont work sodium when even slightly warmed will react quite violently with chlorine gas so this is not really an option even with the design i stated the electrodes must be a considerable distance apart

[Arthur]

Eelectrolysis in an iron cell is the normal way to make Sodium! Sodium chloride is easily available - esp from the sea! If you can get the current up enough your cell will keep hot itself, however you will need to melt the first load of salt first and you need to electrolyse the fused material

 

Any attempt a solar heating will be very clean, in fact the French had a solar furnace to do high temperature research. However they had a whole hillside covered in mirrors which were servo driven to keep the beams all pointing at the target as the sun moved. BUT for your purposes a lens or mirror system may need to be of the order of 10m^2 to get much target material up to a high temperature.

Edited June 16, 2009 by Arthur

[NightHawkInLight]

Eelectrolysis in an iron cell is the normal way to make Sodium! Sodium chloride is easily available - esp from the sea! If you can get the current up enough your cell will keep hot itself, however you will need to melt the first load of salt first and you need to electrolyse the fused material

 

Any attempt a solar heating will be very clean, in fact the French had a solar furnace to do high temperature research. However they had a whole hillside covered in mirrors which were servo driven to keep the beams all pointing at the target as the sun moved. BUT for your purposes a lens or mirror system may need to be of the order of 10m^2 to get much target material up to a high temperature.

 

Yeah the more I think about it the more I realize that using a fresnel lens would just be far more of a pain than it needs to be. I'll likely just use charcoal and a large ceramic something or other as a crucible. That part I can figure out.

 

BTW, thanks for all the feedback guys!

Edited June 16, 2009 by NightHawkInLight

[asilentbob]

I like the idea. I'd say go with NaOH. If you do go with NaCl, add some CaCl2 and/or other chlorine salts to lower the melting point a bit.

 

You may be able to use a iron container and just spray paint some high temperature black grill paint on it... I dunno how much heat that stuff can take though.

[Ralph]

using NaOH is bad when your dealing with hy temperatures you dont want anything that can react with something in the electrolyte being produced which is why the chlorine gas is "funnel" out

[Arthur]

Use a heavy iron vessel and put it in a coke fire to keep it hot Use an aspirator pump to draw the chlorine through NaOH or KOH soln to make bleach or chlorate according to the conditions.

 

Use the vessel as the cathode. Do some calculations about how much metal is generated by how much electricity, don't assume 100% efficiency! Keep the current UP if you want to use the electrical heating effect.

 

Sort out a safe method of work for handling metalic sodium especially hot or molten sodium. Sort out the bulk extinguishing solids to suit the process. Burning sodium is almost un extinguishable, sodium in contact with water may well ignite, firing the hydrogen generated.

[Miech]

Would't it be much easier to mix magnesium powder with NaOH prills and set it on fire in a controlled environment? I've made sodium this way several times. I'd take a small paint can, and make a small hole in the lid. Then fill it with NaOH and magnesium powder, insert fuse, light fuse and stand back. After the reaction has finished, poor in some liquid parrafin to stop any oxidation, and you can carefully take out small ingots of sodium. If you need a higher purity, melt it and let it cool down. Any magnesiumoxide will float and can be easily cut off with a knife after cooling down. Care must be taken however at any point of the procedure.

 

This reaction also works with KOH and BaOH, and probably with some other hydroxides and oxides as well.

[NightHawkInLight]

I like the idea. I'd say go with NaOH. If you do go with NaCl, add some CaCl2 and/or other chlorine salts to lower the melting point a bit.

 

You may be able to use a iron container and just spray paint some high temperature black grill paint on it... I dunno how much heat that stuff can take though.

Grill paint is some of my favorite stuff. I'm not so sure about it at those temperatures either, but if I decide on the fresnel lens I'll likely give it a shot.

 

Would't it be much easier to mix magnesium powder with NaOH prills and set it on fire in a controlled environment? I've made sodium this way several times. I'd take a small paint can, and make a small hole in the lid. Then fill it with NaOH and magnesium powder, insert fuse, light fuse and stand back. After the reaction has finished, poor in some liquid parrafin to stop any oxidation, and you can carefully take out small ingots of sodium. If you need a higher purity, melt it and let it cool down. Any magnesiumoxide will float and can be easily cut off with a knife after cooling down. Care must be taken however at any point of the procedure.

 

This reaction also works with KOH and BaOH, and probably with some other hydroxides and oxides as well.

I like that idea very much if I want to play with some sodium in a pinch. I don't know that I want to burn through my valuable Mg powder before trying other ways first however.

 

I'll have to start looking for a suitable crucible as I poke around the hardware store in the next few days. A frame for my fresnel lens is also a must if I'm going to go that route. It's so large and flexible that it's impossible to hold and focus it without another helping. Even then it wants to sag in the middle, destroying much of the focus.

[NightHawkInLight]

Well, after spilling hot wax all over myself in the first attempt, I have successfully synthesized sodium using Miech's method. Here is the video:

 

I still like the idea of electrolyzing NaCl, and may still give it a shot. Especially since I found that calcium chloride only costs about $10 for 5lbs. If only I had a use for that much...I'll find one I'm sure. Add it to charcoal for creamoras or something.

 

EDIT: A youtube user just made me realize that I was wrong in my reasoning for the chemistry going on here: When I preformed the equation, without thinking I assumed that the reason it worked was because Mg was more reactive than Na. Obviously I forgot the order of reactivity under pressure

 

So if that's not it, how does this reaction work? Searching has yielded absolutely nothing on this reaction.

Edited June 20, 2009 by NightHawkInLight

[rocket]

So if that's not it, how does this reaction work? Searching has yielded absolutely nothing on this reaction.

 

I’ve wondered this myself, the only thing I can think of is ether the heat from the burring Mg is decomposing the NaOH or its acting as a oxidizer. Al also works in the same way as the Mg.

[NightHawkInLight]

I’ve wondered this myself, the only thing I can think of is ether the heat from the burring Mg is decomposing the NaOH or its acting as a oxidizer. Al also works in the same way as the Mg.

Is that so? Al too...Being able to release a chemical so high up on the reactivity list with such low ones could have some seriously cool uses...Especially since Miech said it works for KOH as well. It would be nice to figure out a way to isolate the Na/K away from the rest of the slag other than picking out the extremely small ingots with tweezers...It could take hours for a gram, if the ingots are even large enough to be grabbed at all.

[rocket]

I’ve tried heating up the Na/oxides and other rubbish under xylene to melt it but the surface tension of Na made it impossible to get it to form a larger ball. Some kind of flux might need too be added to the comp to get larger ingots of Na. Edited June 20, 2009 by rocket

[Ralph]

um i am extremely doubtfully that reacting magnesium and sodium hydroxide in this manner will produce sodium metal for the simple reason that sodium is more reactive than magnesium and therefore magnesium can not reduce the sodium ions. its like saying you can make termite with aluminium oxide and iron powder it wont work. the reason i think you are getting sodium like results is because of hydroxide aluminium/magnesium reaction if you put your "sodium" in HCl (muriotic acid) if it is sodium it will very violently react resulting in an explosion after a short delay if it is a magnesium hydroxide reaction than the HCl will neutralise the hydroxide resulting in a possibly burning magnesium acid reaction (evolves hydrogen gass and heat)

[a_bab]

Actually magnesium can reduce even cesium; while it is true that the sodium metal is much more reactive then magnesium, the proposed reaction works.

Once you understand the concept of "equilibrium" in the chemical reactions you will enlarge considerably your views of what can work and what can't.

 

Simply put, the reactions we "all know" are tipically thought for our enviroment. We all know that the water is a liquid, we all see the metals as solids etc. But they can all become gases/liquids whatever with a change of temperature/pressure. Same with chemicals reactions. If you add heat, even the carbon will reduce the sodium from it's compouds. Iron will do it too. This is how we can get the reactive phosphorus (Al will reduce it, C etc). You can see a mixture of NaOH/Mg at your temperature as very inert. No reactions here. So the equilibrium is shifted towards left in the chemical reaction:

 

2NaOH + Mg --> 2Na + Mg(OH)2

 

In other words, we only have the starting chems, sitting in the container, with no apparent change. But if we change the parameters (pressure, temperature) some magic will start to in the happen in case of heat : the Mg will start extracting the Na. At some point, the reaction becomes exothermic: the released energy is enough to sustain the chemical reaction that is taking place.

 

 

Such reactions have been used in the past to manufacture sodium. Lead is a very efficient reducer too, for getting these pesky alcaline metals. Heat is the key.

[Miech]

The hydrogen from the hydroxide will escape in gaseous form, so you won't get MgOH but MgO. I have no clue how the reaction works exactly, it just works.

[crazyboy25]

Would't it be much easier to mix magnesium powder with NaOH prills and set it on fire in a controlled environment? I've made sodium this way several times. I'd take a small paint can, and make a small hole in the lid. Then fill it with NaOH and magnesium powder, insert fuse, light fuse and stand back. After the reaction has finished, poor in some liquid parrafin to stop any oxidation, and you can carefully take out small ingots of sodium. If you need a higher purity, melt it and let it cool down. Any magnesiumoxide will float and can be easily cut off with a knife after cooling down. Care must be taken however at any point of the procedure.

 

This reaction also works with KOH and BaOH, and probably with some other hydroxides and oxides as well.

 

 

Well, after spilling hot wax all over myself in the first attempt, I have successfully synthesized sodium using Miech's method. Here is the video:

 

 

I’ve wondered this myself, the only thing I can think of is ether the heat from the burring Mg is decomposing the NaOH or its acting as a oxidizer. Al also works in the same way as the Mg.

 

 

I’ve tried heating up the Na/oxides and other rubbish under xylene to melt it but the surface tension of Na made it impossible to get it to form a larger ball. Some kind of flux might need too be added to the comp to get larger ingots of Na.

 

 

2NaOH + Mg --> 2Na + Mg(OH)2

 

 

Sorry, but this reaction is total bullshit. There was a thread about this on SMDB and it appeared as if several people got positive results. I attempted the reaction twice and came to a conclusion but no one listened. This is what I hypothesized.

 

 

 

"Sorry guys I’m going to have to side with len1 on this I just retested the experiment with NaOH and aluminum results seemed positive gray solid burns yellow reacts with water almost everything you would expect; almost. I noticed the "sodium" was very brittle previously I had just attributed this to impurities but rethinking it this is what is probably happening:

 

The sodium hydroxide melts and forms a very intimate mixture with the aluminum. The gray stuff is just sodium hydroxide and aluminum fused together when they are added to water

 

2Al(s) + 6NaOH(aq) → 3H2(g) + 2Na3AlO3(aq)+Heat

 

The same reaction occurs as if you were adding aluminum foil to NaOH soln. Hydrogen and heat are produced. But because the mix is so intimate a lot of hydrogen and heat is produced and sometimes that heat ignites the hydrogen. "

 

I have produced very small amounts of sodium by electrolyzing molten sodium hydroxide but the beads were so miniscule when they oxidize there is nothing left. Also molten NaOH is finicky you need to control the temp carefully.

[a_bab]

The reaction would work quite well, but:

-it needs a closed vessel system, and a heavy, pressure resistant one

-once the reaction is done (quick fase) the Na should be distilled off, by applying lots of heat and patience without opening the vessel.

-the yield will be less then theoretical due to the secondary reactions. Extra magnesium is preffered to stochiometrical amount.

 

Now, on MS pretty much everybody had tried this reaction in tin cans and alike, in open air, so there is not much to expect. Just think: if Na is less dense then water, there is no hope that the formed Na won't float in the slag and get burned as it is formed. A closed system is needed, maybe under argon/vacuumed to start with. Large amounts are needed too for getting sizable amounts of sodium.

 

As for the "sodium-like" reaction with water of the slag, many possible byproducts of this reaction can "fizz" in the water: sodium peroxide; sodamide (with N from the air); MgNa alloy etc. It's not the ideal reaction for home production of Na.

 

For someone really keen about Na production, I'd say that reading the WHOLE thread on Na production from mad sci is a must. The conclusion comes fast: nobody has ever developed a simple DIY method for home production of sodium unless melted NaOH is electrolyzed.

 

In the past, Na has been produced by the reduction of NaOH/NaCO3 with charcoal; it took days of red hot maintained vessels till the Na started to distill off (just as the phosphorus reduction with C and sand).

Edited June 21, 2009 by a_bab

[Ralph]

well this reaction will happily occur with magnesium and sodium hydroxide with water or aluminium and sodium hydroxide with water and i believe that the burning proses just burns some mg and melts the two chemicals together forming a water sensitive mixture this will work quite nicely with just magnesium turnings and a small helping hand from a lighter as with turnings and not a fine powder it dosnt react quite so fast but it bubbles vigorously and burns with a yellow flame and appears to be like sodium which magnesium in a sodium hydroxide solution clearly is and can not be