Making Sodium Metal (The Castner Process)

In this video, we have a go at a very interesting and historically significant high temperature electrochemical experiment.
The Castner process involves the electrolysis of molten sodium hydroxide, generating water and oxygen on the anode, and sodium metal on the cathode. This is the procedure originally used to isolate sodium, and served as the industrial route for its production for some time.
By electrolysing a molten bath of sodium hydroxide, we are capable of making and extracting around 0.54 g of metallic sodium from about 90 minutes of work, which isn't too bad for a 'proof of concept' run.
You can find my videos on making sodium hydroxide here:
Explainig how it works: • The Chloralkali Proces...
Optimising the process: • Sodium Hydroxide - Dia...
Building a sodium hydroxide generator: • A Chloralkali Cell - D...
You can also find a similar video of mine, about making aluminium metal, here:
• Making Aluminium (The ...

[@ScrapScience]

I didn't mention it in the video, but if you like the idea of making sodium, you should also check out Nurdrage's video on the topic. While most of you have probably seen it already, he developed a completely separate method for sodium production a few years ago which uses much milder conditions, gives better yields, and is overall much more friendly for home chemistry: kzbin.info/www/bejne/eKSxoJx8n5iqotk This is a much better route for making moderate quantities of the metal.

[@dksmith605]

Sodium production via wet chemistry is definitely on my to-do list, but whether to obtain the jump-start quantity by another method or sacrifice some glassware. I might attempt the reaction in a soda-lime flask, because they are cheaper to destroy. Thoughts? I'd be very interested to see other alkali metals isolated via wet chemistry.

[@ChemTalk]

Thanks for the link. We've seen his videos on sodium production, have you tried that method? From what we've read it is difficult but not impossible to replicate. We have not tried it ourselves.

[@michaelfischer6984]

Nurdrage's method works great. The Baby oil is much thinner than "Normal" laxative type mineral oil and and is closer to the material used in the Potassium videos. While normal mineral oil worked, yield was much smaller and just small balls of Na. I just completed my second run using the baby oil and I got 1 solid 15 gm blob of sodium, 1-2 gms were used as the starter. I used the thermal Mg/NaOh method for the original "starter" . 3 Batches made, all worked and the 2 baby oil bathes had giant lumps. One key I think, is when it is done, prop the flask at a slight angle, stop stirrer, reduce heating, wait about 1/2 hr, then turn off heat. This allows sodium to join into large mass.

[@ScrapScience]

@@dksmith605 That’s definitely an interesting idea. I’d be extremely wary when bringing soda lime glass to high temperatures like that though. A good oil bath is probably essential here. If you try this, just make sure you’re fully prepared for the glass to (possibly violently) shatter at any stage. Hope it goes well!

[@ScrapScience]

@@ChemTalk As much as I’d like to, I’m afraid I’ve never tried it at this stage. Similar to you, I’ve seen quite mixed reports on whether or not people can get it to work. Some describe easy success, while some don’t get anything even with a seemingly perfect setup. I still haven’t been able to determine what differentiates the successes from the failures, but once I can get hold of some magnesium, I’ll be giving it a go myself at some point.

[@ununeniy5843]

if you do high temprature electrolysis you would get very reative cathode mass, that contains NaH and Na2O from reaction: NaOH+2Na=NaH+Na2O(at 500C)

[@myth-termoth1621]

Oh my goodness, this is the first of your vids i have watched, i am 40 seconds in and you have mentioned that three videos with no electrochemistry is your limit. I subscribe ! I am going to enjoy your chanel, of that much i am sure already.

[@TeslaFactory]

Nice to see you presenting in videos now! Your confidence in making videos shows, making for great content. More science than scrap! :)

[@tp6335]

I did this a while ago with a nail and a rusty smelting ladle. I got only milligramms of sodium but the nice thing was that all the rust went away and the ladle was in better condition than before the experiment

[@YouMockMe]

Wow, those globs of Na forming were so cool. Great experiment, thanks for sharing! Cheers!

[@johndoe7017]

This is actually really interesting! I hope this channel blows up

[@nixo0077]

Very interesting processin home conditions. I will be waiting for for next videos, thnaks for your work and YT activity. Best for you from Poland

[@ZoonCrypticon]

A great job you did there, congratulations!

[@Jawst]

I absolutely love your videos everything about them!!! Most of all I love how serious you take safety

[@AndyMaker]

Excellent project! Going to add this to my projects to make list 👍

[@aurora7207]

Thanks for including your "failures", most people think they are BAD to include, which tells you something about how they approach science.

[@christopherleubner6633]

Yup that is helpful information 👍

[@drmarine1771]

Well explained and good effort mate.

[@davidapp3730]

Thank you for sharing that experiment. Interesting.

[@herwew7476]

Great Video, looking forward for NaCl electrolysis!

[@incognitomontoya1131]

Great video chief! Your channel is kick ass

[@magnuswootton6181]

couldnt ask for a better go at it here, this went quite well for him I think.

[@sebastians7346]

this channel is awesome keep it up!!

[@harryniedecken5321]

Thank you for the great videos.

[@joshuacollins385]

One of the only channels I clicked the bell icon for and I still don't get notified about your videos. :( Keep making amazing videos

[@ScrapScience]

Thanks mate, glad you like the channel! Hopefully KZbin fixes their notification system soon, but sadly I'm not counting on it.

[@foox-art]

For scooping out the sodium, perforating the spoon with small holes can help separate the sodium from everything else!

[@jimnoonan7511]

Brill. Very well explained and really interesting thanks

[@johnmcclain3887]

Thanks for a good video on an odd but interesting process. I've long known the process for aluminum but never investigated sodium. I suspect the same process or similar can be used for potassium. I enjoyed the fact you showed your failure, analyzed it, and resolved it. The "little glitches" happen in almost anything one does, less than straight forward. Thanks again.

[@ScrapScience]

Thanks! Glad you enjoyed the video. Interestingly, trying this particular process for potassium doesn't yield good results. The issue of the metal being soluble in the molten mass is much worse when working with potassium and potassium hydroxide. Sadly, from reports of many people trying it, there is no temperature range or setup which can yield potassium like this. With an inert atmosphere, some have been able to make milligrams of the metal (without being able to recover any), but I’ve never seen anyone extract potassium like this with any success. The electrolytic production of potassium requires melting a different salt, which I'll hopefully be attempting at some point.

[@randomergy683]

Nice work man (: I'm glad your channel popped up in my feed. We seem to have common interests. Have a subscriber my good sir!

[@weldmaster80]

Amazing stuff. Subbed

[@Scrogan]

I really like this channel. Electrochemistry is cool.

[@JustAnotherAlchemist]

Me and my uncle put ordinary table salt in a stainless steal cup, much like what you have there, and stuck it in his ceramics kiln.... THAT... did not end so well.... From what we could tell from the damage, it first reduced (well, oxidized, actually) the entire stainless container into some kind of super rust. It then fluxed the rust to the point that it was soluble enough that it could soak into whatever brick the kiln shelf was made of. It then proceed to drip down through the bottom of this shelf, and onto the pieces underneath, largely fluxing and dissolving them, melting them to the shelf they were on. There was apparently some gasses, or eruptions, during this whole process, since just about everything in the kiln had molten splatter marks on them. Needless to say, turns out, salt is about the worst thing you can put in a kiln.

[@noodlesoup2281]

Chlorine gas!!! 😵😵😵😵

[@heavenbot]

You need more recognition, this is wonderful! Definitely sharing your channel with my fellow dangers to society!

[@TimPerfetto]

I really dont have time for this right now -- can you help my cat he has loose bowel movements and refuses to eat his har

[@heavenbot]

@@TimPerfetto mix shed fur with a smooth paté wet food, as much hair as you feel is necessary

[@TimPerfetto]

@@heavenbot Thats a good idea thank you I am worried if he doesnt eat enough hair he will spontaneously combust

[@heavenbot]

@@TimPerfetto add CCl4 to prevent combustion

[@TimPerfetto]

@@heavenbot How rude of you -- he already has liver issues and what do you think I am a dry cleaner?

[@jastintheceooffinanasapost6204]

Quick reminder that Molten Sodium hidroxide DISOLVES GLASS Keep in mind if anyone desires to attempt this, for your own safety just be carefull about it Great video again!

[@christopherleubner6633]

Use 80% NaCl and 20% NaOH, use screen of course seel wool as the separator spot welded to a cheap steel pan. use a big block of graphite rod as the anode and a steel plate as cathode. A big flower pot works well for your crucible, seal your rod with pottery clay and pack it in sand. If you get it hot enough you will get sodium as a vapor. Condense with a steel tube into mineral oil.

[@AdricM]

fun watch, nice use of your electric furnace.

[@sagarugolden3798]

Nice job

[@jozefnovak7750]

Super! Thank your very much!

[@studyadda4532]

19:14 real truth doesn't matter I had seen it many times in another videos but every time I am ready to see it again

[@firstmkb]

I tried a version of this in the 1970’s with NaCl on my mother’s electric range, fortunately failing completely. The NaCl melting point is 483 C higher than NaOH, and the range just couldn’t quite reach 801 C. Information was so much harder to find then!

[@ScrapScience]

I actually know of quite a few people who have attempted direct electrolysis of molten NaCl, and I've never heard of anyone successfully extracting sodium from it, so don't feel bad! Combining temperatures of over 800 C, molten sodium, and hot chlorine gas is a pretty tricky thing to try to handle. I can't quite imagine what home chemistry would have been like in the pre-internet days (much more difficult I'd imagine), so I really admire the fact that you gave it a go anyway.

[@Ottmar555]

@@ScrapScience I'll try to build a Down's cell hopefully this year. The only videos are from industrial scale operations. I'm curious as to how hard it is to pull off the downsize. I'm more worried about the chlorine, as I'm not well versed in gas manipulation.

[@noodlesoup2281]

Pretty sure you would have gassed yourself with chlorine if you were successful unless you had GOOD ventilation. Be careful

[@FirstLast-tx3yj]

@@ScrapScience you mentioned there is a better way that was discovered to produce sodium after 1920s what is that method??

[@ScrapScience]

@@FirstLast-tx3yj The Downs' process is the one. It involves electrolysing molten sodium chloride instead of sodium hydroxide. I talk about it very briefly at about 7:50 in this video.

[@experimental_chemistry]

Nice to see that it actually works in a homelab scale - I've never succeeded wirh this before... 😞

[@RafaelSCalsaverini]

What happens if you crank the heat and let the sodium dissolve into the melt and then start slowly cooling it? Will it recrystalize?

[@aquarius1647]

Hi, I wanted to make this experience last summer but couldn’t manage to have a stable temperature of around 320ºc. Would you have any recommendation ? I already have a home made charcoal furnace but it goes to 800ºc and that’s a little bit to much😅.

[@ScrapScience]

That's definitely a tricky thing to try to get temperature control with. If you work on a small enough scale, it might be possible to heat up your sodium hydroxide with your furnace, and then remove the molten mixture from the heat source, and keep it molten with just the current of electrolysis. That way if it gets too hot, you can just turn off the current, and allow it to cool a bit before turning the current on again. It might take a bit of work to get the temperature balance right, but others have succeeded with this kind of setup before.

[@CatboyChemicalSociety]

The graphite anode is nice because it seems the sodium doesnt explode as it forms in the cell unlike with a nickel anode maybe because the O2 makes CO2 at the graphite anode?? which then forms sodium carbonate try to see what that solid mass is whether its pure NaOH or a mix of that and carbonate.

[@ScrapScience]

I like this idea, makes a lot of sense. Sadly, I've already neutralised all of the waste from the cell, so I might have to do some further testing at some point...

[@janami-dharmam]

The leftover on the pan was very likely sod carb because sod hydroxide will dissolve in water real fast.

[@randomhuman1965]

Awesome!

[@bpark10001]

To clean up the sodium, add a LITTLE ethanol to the oil & stir well. Put in the dirty sodium. The alcohol will react mildly with the sodium & clean up its surface. Scoop out the sodium & put in fresh oil.

[@pe4958]

1:49 ❤ Davy...a true (chemistry) man's man

[@glennkrieger]

Neat. It would be great to know what the settings were for the electrolysis.

[@ScrapScience]

I just had it connected to 5 volts DC (capable of 25 amps maximum) in this case. Nothing else to it.

[@Berghiker]

I used two iron nails years ago and it worked well.

[@JoakimfromAnka]

Yo, how about some video with high temperature reactions of NaOH and various stuff? I red on wikipedia that NaOH will react with Fe at 500c.

[@waschbaers_werkstatt]

great video, you can clean the sodium if you add under mineral oil (VERY GENTLY!) few drops of ethanol, the reaction should clean up the surface. test it, but be prepared and very careful

[@ScrapScience]

As it turns out, this is exactly how I cleaned and coalesced the sodium droplets - though I ended up using isopropanol instead. I didn't really show it in the video, but it definitely cleans up the sodium very nicely.

[@waschbaers_werkstatt]

@@ScrapScience nice, i note that, if i somewhen make sodium metal by myself :D i got an induction heater that makes very fast iron pipes glowing red, the same is for graphite i think. i like that method... hmmm sounds like a video idea :D

[@waschbaers_werkstatt]

@@ScrapScience another suggestion, if you over volt the electrolysis, the excess voltage turns into heat, i think if its molten you can keep it molten that way.

[@commonsense-og1gz]

you could extract the sodium, then burn it in pure oxygen to get sodium peroxide, which can be used in co2 scrubbers, dropped in water to produce sodium hydroxide and hydrogen peroxide, or whatever you want to do with it.

[@quantumlab9130]

Just be very careful with the hydrogen production, one time when I was making sodium metal, the hydrogen mixed with the oxygen, then exploded and I almost gave myself a piercing.

[@petrlaskevic1948]

Did you make it in a garage?

[@kusters_chip_channel]

Saya baru menemukan channel ini, saya senang dan ingin belajar banyak tentang kimia dari anda guru, saya ingin menjadi murid anda, boleh ? Saya ingin sekali belajar membuat pottasium sianida untuk tambang emas, maukah berbagi ilmu untuk pengemar channel siend ini 😊

[@kreynolds1123]

Could you help. How much heat energy is released converting a gram of sodium metal into sodium hydroxide in its various hydrates? I can figure out how much hydrogen is release and look up its higher heating value. But I dont know what to lookup to determin the heat generated in making sodium hydroxide from sodium and water or what to look up to determin how much heat is released when hydrating sodium hydroxide.

[@ScrapScience]

The thing you'll want to work with is the 'standard molar enthalpy'. I won't explain the maths involved because there are countless online resources that explain it better than I could. Overall, it's an easy way to calculate how much thermal energy is released by a reaction. All you'll need to do is look up the standard enthalpies of your reactants and products. It might be a little difficult to find enthalpy values for sodium hydroxide in obscure hydration states, but the common ones should be very easy to find.

[@wesleycastner4860]

Think it cool as hell nvr met ne1 with my last name till i heard of this process never thought name was widespread or known

[@thefutureexperiment6931]

After you put it in the water and it fizzled out are you now left with sodium hydroxide? Also i put up a vid of my cell....tell me what you think and if have you used the polymerized pva membrane at all?

[@ScrapScience]

Yep, the reaction of sodium and water generates hydrogen gas and sodium hydroxide in solution. And yeah, I really like your NaOH cell, it's well built and looks like it'll do the job well. If I had one suggestion, I'd say it's a good idea to loosely cover the cathode chamber with something. Generally, you want to keep CO2 from the atmosphere away because it will slowly react with your sodium hydroxide product. I find that draping a piece of cling film over the cathode compartment (with some holes poked in it, to let the hydrogen out) will do the job nicely. Regardless, your setup is very good here. So far, I haven't tried the PVA membranes, but I'm very keen on trying them at some stage. I just have so many video ideas that I haven't got around to it yet (and probably won't for quite some time sadly).

[@thefutureexperiment6931]

@@ScrapScience Word up...thanks for the feedback on the cell .... I'mma try that course I think my yield was low even though I didn't record the amounts. After the naoh side turns sort of golden color it does dissolves Al foil but after I evaporated the water and then ad water back to make a solution it seems weaker. I need to think more experimentally about it and write stuff down.

[@etherlon2766]

Would this work for extracting potassium from KOH? (Great vid BTW)

[@ScrapScience]

Thanks! I’m afraid potassium is nearly impossible to extract this way. The issue of the metal being soluble in the molten mass is much worse when working with potassium and potassium hydroxide. From reports of many people trying it, there is no temperature range or setup which can yield potassium like this. With an inert atmosphere, some have been able to make milligrams of the metal (without being able to recover any), but I’ve never seen anyone extract potassium like this with any success.

[@etherlon2766]

@@ScrapScience Thanks for the reply! I'll will definitely be trying this next time I need a little sodium metal. Even if the Castner process you showed didn't make much of a yield, the items needed are more accessible to me. Cheers!

[@xml7sxGaming]

Sodium hydroxide is very hygroscopic. try vacuum desiccation on the solid, might help.

[@ThePeterDislikeShow]

Could you electrolyse molten sodium chloride to avoid the problem of generating water?

[@ScrapScience]

Yes! However, the higher melting point makes the cell more complicated to build, and the produced sodium must be protected under argon as it forms (again, due to the high temperatures involved in melting NaCl). I'll be making a video on this eventually.

[@hardwareful]

NaO melts at 1132 °C, but with graphite mixed in.. what are the odds that Na2C2 is formed?

[@mishmash6991]

NICKEL FOR THE CATHODE,& GRAPHITE FOR THE ANODE (NICKEL CAN BE USED FOR THE ANODE ALSO). FOR MAKING SODIUM METAL BY PUTTING MOLTEN SODIUM HYDROXIDE (LYE) THROUGH ELECTROLYSIS.

[@SodiumInteresting]

Could you have used the cup as your anode? Did you find over time a golden film forms on the sodium in the oil

[@ScrapScience]

Stainless steel doesn't hold up well as an anode in this process. It's such a terrible anode that using the cup as the electrode would quickly eat through the metal, spilling the contents everywhere. I haven't found that the sodium forms a golden film, no. I've only observed a white coating from the oxides and hydroxides that build up.

[@SodiumInteresting]

@@ScrapScience just uploaded a short to show you. The oil is Johnsons baby oil which has parfum and Isopropyl palmitate as well as the liquid paraffin kzbin.infoYpSXGSzuBVc?feature=share

[@ScrapScience]

Interesting. I'd definitely assume it has something to do with the impurities in the mineral oil (which is the reason why I always avoid directly using Johnsons baby oil as an inert oil), but I couldn't tell you what it is.

[@parttime9070]

Take a small glass tube, maybe 12' long. As the sodium bead is bouncing around on the water catch the bead with one end and light the gas being given off by the sodium..

[@robinyilmaz1155]

Hey, you say the graphite got eroded, but wouldn't it be corroded instead? I'd really like to know, it's for a university project!

[@ScrapScience]

It's more likely to be corrosion, yes, since the carbon is being oxidised in the process. At the time, I wasn't sure whether the electrode was just falling apart from the stresses of gas generation, or chemically oxidising. I guessed it was just being eroded by the high temperatures and gasses, but corrosion is much more likely (maybe it's a bit of both actually).

[@justagoose6186]

Can you also concentrate drain cleaner and get the sodium hydroxide from that?

[@ScrapScience]

Concentrating a solution of sodium hydroxide to get the pure solid is very difficult. Prolonged temperatures of over 300 C are required to get rid of all the water, and the heating will tend to make the solution bubble and spit everywhere. It's possible, but it's much easier to get a drain cleaner which consists of the pure solid sodium hydroxide instead.

[@justagoose6186]

@@ScrapScience I see

[@hamzashaheen3581]

I Have Recently Made Pure Sodium Nitrate Salt And When I Was Heating It With A Beaker It Melt, Isn't Using It Instead Of sodium Hydroxide Better ? Because Molten NaNO3 Is A Lot Easier To Handle Than Molten NaOH Which Isn't Only Very Hot But Also Far More Corrosive (When I Used Cheap Stainless Steel Container To Handle It The Container Oxidized)

[@ScrapScience]

Sodium nitrate is far too strong an oxidiser for this to work I'm afraid. While the electrolysis will proceed, any sodium you make on the cathode will instantly react with the molten nitrate. In fact, it's much more likely that the cathode will simply reduce nitrate ions instead of sodium ions anyway.

[@silverback3633]

Can you do a safe reverse process of generating electricity by oxidizing Sodium metal?

[@deadman746]

Thank you for this. Now, not that I'm going to try this, when they electrolize salt water to bubble chlorine out, what happens to the sodium? Does it combine with the OH in the water to make NaOH and bubble hydrogen? And if so, how to they get rid of the hydrogen in the gas? Burn it?

[@ScrapScience]

In a solution of sodium chloride, the cathode reaction actually reduces water to hydrogen directly - sodium ions are much more difficult to reduce, so don't take part in the reaction at all. If you were to try this in an undivided cell, you'd eventually end up generating sodium chlorate (which I have a video about, kzbin.info/www/bejne/hGWYdZ-NgbZlZ5o ), and if you manage to separate the anode and cathode reactions, you'd end up with the industrial process for making NaOH (which I also have a whole series of videos about, starting with kzbin.info/www/bejne/ioWkmGd8ath8j9k ).

[@deadman746]

@@ScrapScience Thank you so much. I hope you don't mind another couple of questions. When you do Castner in a stainless steel crucible, (1) wouldn't you get some current through the stainless steel, and (2) if so, would this have something to do with corroding the stainless steel?

[@ScrapScience]

No worries, I'm always happy to answer any questions in the comments! With the stainless steel crucible, there won't actually be any meaningful current flowing through it - provided the electrodes aren't touching the edges of the container in any way. The reason for this is the fact that the molten sodium hydroxide is only conductive to electric current in the form of ion migration, whereas the stainless steel is only conductive for electrons. The electrodes themselves (being connected to the external circuit) perform their respecive reactions as a way of essentially converting 'electron current' into 'ion current'. Since the crucible isn't connected to the external circuit, it won't conduct or take part in the reaction. As for your second question, the corrosion of the stainless steel is simply a consequence of the high temperature and the intensely corrosive nature of the molten hydroxide. If you were to actually use the crucible as one of the electrodes in the process, you'd observe one of two things: 1) If you connected the crucible to the negative terminal of the power supply, the cathodic (reducing) conditions would protect the metal from corrosion to some degree. However, the surface of the crucible would then start making sodium over the whole surface, producing tiny beads of the metal all over the place, and making it more difficult to collect the product. 2) If you connected the crucible to the positive terminal of the power supply, the anodic (oxidising) conditions would rapidly corrode the stainless steel, probably etching through it in a few minutes I would think.

[@janami-dharmam]

@@ScrapScience you can do that if you an electrode that has high overpotential for H+ ions; for example mercury. then sod will dissolve in Hg and you will get a dilute amalgam

[@deadman746]

Thanks again. The ion transport stuff sounds like how dendrites and axons work. It annoys me when people call that electrical, because there are important differences, such as speed. I know more about organic chemistry, but in prison I had a chemist friend, now I can write him and impress him with the name Castner. I always eat organic food because inorganic food is usually way too crunchy.

[@markshort9098]

i tried the nurdrage method using menthol as a catalyst but mine failed and chewed up the flask.. i think my sodium hydroxide was to wet even though it was out of a new container.. i haven't tried drying sodium hydroxide yet, does anyone know if calcium chloride is good enough to dry sodium hydroxide? or any other good way to dry it.. some motorbike and aircraft parts are made of magnesium and i'm keeping an eye out for magnesium scrap because the thermite method works really easy and has a 40% yield

[@TeslaFactory]

If you can dry it with CaCl2 in a vacuum or reduced pressure, I'd guess you'd have better luck

[@leeroy144]

I did the nurdrage method with dioxane and it worked very well. It ate up one of my flasks, but I anticipated that and used a cheap one.

[@leeroy144]

I also used extremely fine magnesium powder and ground the sodium hydroxide up very fine.

[@markshort9098]

@@TeslaFactory yeah I just don't know yet who's going to win at absorbing the water since both sodium hydroxide and calcium chloride make really good desicates.. when I have time I'll stick both in my drying box and see who wins

[@markshort9098]

@@leeroy144 the method with dioxin was the thermite reaction in a soup can and the sodium is separated out in the dioxin and shouldn't eat the flask, mine didn't eat the flask with the thermite and dioxin method.. maybe I missed something but the wet processes all used paraffin oil to my knowledge and it was the wet process that ate my flask

[@nicksgarage8295]

what voltage r u running on the electryolis.s

[@ScrapScience]

5 volts

[@squirlboy250]

So when you drop the sodium metal in the water does it turn it into salt water?

[@ScrapScience]

The reaction generates hydrogen and sodium hydroxide. The hydrogen bubbles off the surface and the sodium hydroxide stays in solution.

[@robertkeyes258]

MIT used to start off its intro to chemistry class by throwing a large chunk of sodium metal off of the "Smoot" bridget into the Charles river, to the amusement of all. However, someone else tried to do similar but their sodium was covered in petroleum jelly, which kept it from reacting with water, and it washed up on the river bank and caused a lot of concern from the busybody police and fire departments, who blamed MIT.

[@demidrol5660]

I would really like to see how nickel would behave as an anode

[@heisenbergstayouttamyterri1508]

As far as I'm concerned Sodium is soluble in NaOH(l)!!! So the produced Na might get lost in the process( albeit very low amount if not stirred to dissolve)!!!

[@Lyle-In-NO]

I would have guessed the sodium would have reacted w/ the humidity in the air when scooping out the globules. Was it a particulary non-humid day, or is that even a concern?

[@ScrapScience]

Sodium's reaction with atmospheric humidity is not that fast (even when the sodium is molten) - it's really not something to worrry about. Of course, it does react with water and oxygen from the air over time to form an oxidised layer on the surface - faster than the vast majority of metals. It's just not something that occurs very extensively on the timescale of a few seconds.

[@andraskis6890]

Can I use an iron nail (or copper wire) instead of nickel??

[@ScrapScience]

As a cathode, yes. Both of those options are fine. As an anode, copper is not a good choice. Iron may be okay. Graphite or nickel is ideal.

[@andraskis6890]

Thank you!

[@franciscoparraguez4576]

🌱🌱🌱👏👏👏👏👏👏👏👏👏👏👏🍀 thank you so much !!!!!!

[@CatboyChemicalSociety]

graphite doesnt work for this because of sodium carbide being produced if the cathode is graphite which is this shitty black crust. it must be nickel or steel. This process scares me a lot because I had it explode on me already awhile back.

[@ScrapScience]

Interesting. I assumed it must be sodium reacting with the carbon in some form, but didn't consider the carbide being generated. I was honestly very surprised to not experience any little explosions. I was expecting it at every turn.

[@CatboyChemicalSociety]

@@ScrapScience yea im gonna re visit it thanks to the idea of using a graphite anode but the yield may be lessened as the Na2CO3 builds up.

[@WaffleStaffel]

@@ScrapScience Maybe use the measuring cup as the cathode? I read about doing that on Science Madness a few years ago, but don't recall whether it was definitively advised for or against. Great job though, very clean setup!

[@ScrapScience]

@@WaffleStaffel That’s definitely not a bad idea, and would help by cathodically protecting the container to some degree. I didn’t end up trying it because I thought the sodium might be made in super small globules all over the place, and would be difficult to combine. Now that I think about it though, the increased current capability of that might be worth it anyway. Thanks!

[@WaffleStaffel]

@@ScrapScience Maybe in that case the cup should be the anode? The sodium is forming at the cathode? You can probably find a decent supply of crucibles at the dollar store. Thanks again, I've followed you for a few years, these videos are super fascinating to me, especially this one.

[@gsestream]

try more usual metal making by chlorides molten electrolysis, like iron and aluminium chlorides, should be very low temp like 180C for aluminium, and at max 800C for iron

[@MadScientist267]

That's trace water in the oil its reacting with, and a common method for drying it.

[@atari7001]

I understand that a eutectic of sodium iodide and sodium hydroxide would lower the melting point considerably and reduce the solubility of sodium in the melt (preventing the need for precise temp control). I have yet to find anyone who has reported any results, however.

[@ScrapScience]

As far as I can tell, the sodium iodide/sodium hydroxide eutectic is only applicable for electrochemistry when the anode is a sodium alloy in the first place (i.e. it’s only good for electroplating sodium rather than isolating it from the salt). I would strongly suspect that the iodide would interfere if you tried this with inert electrodes. I’d predict that the anode would generate iodate and/or hypoiodite ions as the oxidation product on the anode, and would then prevent sodium formation due to the presence of these oxidisers in the melt. It might make a few milligrams of sodium, but I doubt it’s capable of making much more than that sadly.

[@jolotschka]

Have to cover the beaker with the sodium and water so hydrogen can get more and will ignite spontaneously. Or put the piece of sodium in some paper and then drop it in water. Gives similar effect

[@hmada-ng8mj]

Does the electrolysis of H2O2 produce gas oxygen ؟

[@ScrapScience]

Yes, water is generated on the cathode, and oxygen gas is generated on the anode in this case. But if you want to make oxygen from peroxide, it's much easier to just use an oxidising agent like manganese dioxide, or a catalyst like platinum or silver.

[@Critical-Smoke]

can other electrodes be used? nickel or lead or copper?

[@ScrapScience]

Nickel is fine to use as both the anode and cathode here. In fact, it's an ideal choice. Lead will not work, and it will also melt, so don't use that. Copper will work fine as a cathode, but I'd avoid using it as an anode (it will oxidise and disintegrate, contaminating your cell).

[@Critical-Smoke]

and how do you control the temperature so exactly? if i have a furnace (the cheap cylinder with insulation and propane torch), how do you keep the temp so low and stable? do you use some kind of gas regulator?what fitting and couplers?@@ScrapScience

[@ScrapScience]

I use an electric furnace, so temperature control is easy. Achieving temperature control with a propane furnace will be very tricky given the narrow temperature range for this reaction. I'm not exactly sure of a good method to do it, sorry.

[@NoahSpurrier]

Why not use the cell container as the anode?

[@ScrapScience]

Stainless steel doesn’t make a good anode material. Doing this would quickly disintegrate the crucible and spill the molten sodium hydroxide everywhere.

[@TheHuntermj]

Yo, What part of Aus you from? I'm in WA.

[@ScrapScience]

Tasmania's the one

[@TheHuntermj]

@@ScrapScience Oh hey, I lived in Stanley and Smithton for about 3 years

[@ScrapScience]

Oh cool! I've only ever given them a quick visit, but they seem like nice spots

[@TheHuntermj]

I know you can react Magnesium metal with Sodium Hydroxide to give Sodium metal, could you melt Aluminium in the furnace and add Sodium Hydroxide to that?

[@ScrapScience]

While the thermodynamics of this reaction make it technically possible, the required temperatures call for an extremely elaborate apparatus to contain the sodium, if the reaction can even be initiated. As far as I'm aware, others have tried this type of reaction to no success.

[@TheHuntermj]

@@ScrapScience it can't be too far off in terms of energy balance, up for a bit of high temperature electrolysis with biphasic molten metal and molten salt?

[@TheHuntermj]

@@ScrapScience probably better with NaCl or another halide tho due to melting points

[@janami-dharmam]

@@TheHuntermj actually you can use a KCl and NaCl eutectic that has a lower melting point.

[@elyesmehri3067]

Does it works with Potassium HydroOxide to get Potassium ?

[@ScrapScience]

It seems potassium is nearly impossible to extract this way. The issue of the metal being soluble in the molten mass is much worse when working with potassium and potassium hydroxide. From reports of many people trying it, there is no temperature range which can yield potassium like this. With an inert atmosphere, some have been able to make milligrams of the metal, but I've never seen anyone generate reasonable quantities. Making potassium electrolytically requires melting a different potassium salt, usually the chloride. This requires a much more complex setup though.

[@Chemistry_man07]

what kind of battery did you use?

[@ScrapScience]

I don’t understand. When did I use a battery?

[@Chemistry_man07]

@@ScrapScience for the electrolysis. What did you use as a source of current

[@ScrapScience]

@Chemistry_man07 Oh, I see. I was using the 5 volt output on an ATX power supply from an old desktop computer in this case.

[@Chemistry_man07]

@@ScrapScience handy. Good thinking

[@sidjoosin6549]

why not use steel container itself as cathode or anode?

[@ScrapScience]

This can definitely be done, and will give you a higher current (resulting in a higher production rate). However, there are a couple of issues with doing this: 1) Using the crucible as a cathode will generate sodium all over the place, generally in tiny beads that are difficult to coalesce. Maybe they'd join together over time, I don't really know... 2) Using the crucible as an anode will run the risk of oxidising through the container, spilling the molten hydroxide everywhere. This is particularly likely when using iron or stainless steel as a crucible. A nickel crucible would do this job effectively though, and in that case it's a very good option.

[@chanheosican6636]

Hmm what the risk of an Sodium explosion? Still a very cool video working with Molten sodium hydroxide cool video.

[@ScrapScience]

The risk of a sodium explosion is very high when doing this. Hence why I did it on such a small scale. While I didn’t get any explosions in my experience here, many others have reported frequent explosions from these cells, so it’s something to keep in mind.

[@flameflame3477]

Where did you get nickel metal?

[@ScrapScience]

I just bought some nickel ribbon online, but it's also available as pure nickel guitar strings.

[@vaclavmatousek3007]

I wonder if any startup has thought of using Castner process to make sodium for seasonal energy storage.

[@Bunthar86]

Why didnt you just use the crucible itself as the cathode? Much larger surface area and easier to evenly orient around the anode.

[@ScrapScience]

I've tried this in the past for similar processes, and using the crucible as a cathode just seems to generate sodium all over the place, generally in tiny beads that are difficult to join together and collect efficiently. It's great for making a lot of sodium, but terrible for making the sodium extractable from the melt.

[@Bunthar86]

Have you tried using a glass dropper to suck up the beads? Thats how I deal with mercury (in which I keep submerged under oil). The glass in those droppers is thin enough there shouldnt be any issues with cracking. Just make sure your quick with it though. BTW awesome video, you dont skip on substance like most other videos do.

[@ScrapScience]

I've seen others using a pre-heated glass dropper for sodium extraction, but never really gave it a second thought. It's definitely not a bad idea at all, thanks! And yes, glass in contact with molten sodium hydroxide isn't the best combination, but I'm sure it should be fine if it's not just left lying in the melt for too long. Thanks for the kind words!

[@okboomer6201]

Okay same thing, but using a Lincoln Arc Welder. Takes about 30-40 seconds.

[@windigo000]

it's nice noone has to mention "don't drink molten NaOH" any more 😁 humanity has some hope ;)

[@crystalsheep1434]

Cool

[@mernokallat645]

Davy actually used slightly moistened sodium hydroxide, not molten sodium hydroxide and a battery which gace him hundreds of volts.

[@thewoods9684]

What if you mix it with a chlorinated solvent?

[@ScrapScience]

I'm not a fan of the possible explosion risk honestly...

[@abdulhayee180]

Can you make it from Down's process

[@ScrapScience]

Yep, eventually. In fact, I talk about this at 7:51

[@Tony-nl6pf]

I have Potassium Hydroxide, can I assume the process is the same?

[@ScrapScience]

I’m afraid potassium is nearly impossible to extract this way. The issue of the metal being soluble in the molten mass is much worse when working with potassium and potassium hydroxide. From reports of many people trying it, there is no temperature range which can yield potassium like this. With an inert atmosphere, some have been able to make milligrams of the metal, but I've never seen anyone generate reasonable quantities. Making potassium electrolytically requires melting a different potassium salt, usually the chloride. This requires a much more complex setup though.

[@Tony-nl6pf]

@@ScrapScience Oh wow, didn't know that. Thought it would be the same. Thanks!

[@ashishgupta7187]

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[@kylecrane5751]

Please don't take this personally, but you kind of remind of Vitalik Buterin if he was chem tuber. Good vid on the castner process tho.

[@ScrapScience]

Haha, no I can definitely see it too. And thanks!

[@kreynolds1123]

Just pointing out, most sodium hydroxide purchased from a hardware store will be a monohydrate.