Home made downs cell?

[Runninfarmer]

This goes with the extracting sodium thread, but is it possible to make a homemade version of a downs cell?

[woelen]

This will be extremely difficult for the hobby chemist. Only the most brave and well equipped persons manage to make Na-metal at home. The safety issues are enormous.

 

Using NaCl is more or less out of the question. Its melting point is way too high and it is near impossible to achieve that in a clean vessel for reasonable quantities for prolonged time, and perfectly isolated from air.

 

Some people have made attempts to do this with NaOH instead of NaCl. The melting point of NaOH is much lower, but the use of this is certainly as dangerous as the use of molten NaCl. NaOH is corrosive and what do you think of NaOH at 350 C? Again, you need perfect isolation from air, and a corrosion resistant vessel (IIRC a nickel vessel could do the job).

 

Some people over here at SFN suggested the use of NaNO3 as a low-melting salt, but that is insane. The nitrate ion is a good oxidizer and under such conditions you won't get Na-metal, but most likely nitrogen gas, maybe nitrite ion and maybe NO and N2O at the cathode, but certainly no Na-metal.

 

Conclusion: Making Na at home is extremely difficult and requires extensive equipment. For me, it is beyond what I do, too dangerous.

[Vrej]

NaNO3 is a good idea although I haven't tried it.

 

I had KNO3 which has a slightly higher mp (350 C I think)

Electrolysis is very slow. I had the idea to add another salt to it.

KCl was not available to me so I had to use KI.

Damn iodine vapors! Although they condensed and I had some nice crystals on the glass walls.

 

Electrolysis was quite fast and I was able to produce K.

I used a iron rod as cathode and a glass envelope to seal the K. I dropped a water droplet and sparks flew. I dropped some more, more sparks.

I poured water and the stuff warmed up and that's all.

Oh yes, anode was graphite rod. That stuff desintegrates.

Any damn material you might use as anode will desintegrate I guess.

 

Perhaps a few mg of K produced. It is very tough to produce this elements.

Have plenty of propane or whatever you use ready.

 

And be smart when you do this. Protect your eyes.

[soultech]

I have come across KCl (Potassium chloride) in jars at the supermarket labled a salt substitute ingredient for cooking.

[Vrej]

But it's probably expensive. NaCl is the real abundent stuff you can buy at grocery but everything else can be bought at pharmacie which sell at 10x the normal price.

It also depends on where you live. I'm sure KCl is not available to me.

[woelen]

I don't believe that you made potassium when one of the ingredients was KNO3. The nitrate ion is a strong oxidizer, and certain at 350 C or hotter, it oxidizes (and ignites) all kinds of materials. Even much more inert compounds like wood, paper, sulphur and carbon are ignited, so you think that metallic K can survive an environment with nitrate ion in it?

[Vrej]

I don't know. What compound do you think it formed and why were sparks given off when I added a drop of water?

[Mr. Bill]

KCL is widely available as Murate of Potash at your local garden supply. Four pound bag earlier this week was US$8.95.

 

In commerce, the melting point of NaCl is depressed w. CaCl2 addition; ignore the Ca+, it really won't be an issue -