Subject: Re: Sodium metal
From: "Richard A. Weisiger" <dickw@itsa.ucsf.edu>
Date: Sep 18 1996
Newsgroups: rec.pyrotechnics

tonywilk wrote:
> 
> >> > Can anybody tell me how to make sodium metal?
> *snip* 
> >From what I recall, it's a process similar to electrolysis of hydrogen
> >and oxygen from water
> >- first, take 50 lbs of salt, heat until a liquid,
> *snip*
> 
> You forgot to mention the stove setting...
> I guess over 800 C would be about gas mark 24  :-)

Actually it _is_ possible, but VERY hazardous. If you use sodium
hydroxide (e.g., lye, MP 318 celsius, 604 F) instead of salt, you can
melt it over a gas flame using a steel container (NOT GLASS OR ALUMINUM)
and electrolyze it to make sodium metal. Using a 6 volt battery and two
copper electrodes, you can make a small blob of molten sodium on the
negative electrode while liberating oxygen at the positive electrode. I
did this in 1963 when my high school chemistry teacher challenged me to
make sodium, and won the bet. I would never do it again because:

1. Molten lye at 600 degrees will not only burn you, but will dissolve
you very effectively. _Room_temperature lye _solutions_ will rapidly
turn your cell membranes to soap. This is the pure stuff and is about
1000 times more reactive because of the high temperature. Tiny splatters
will (and did) put holes in protective clothing, and could easily burn
or blind you.

2. Unless you have provision to work under an inert atmosphere
(nitrogen, argon, etc), the molten sodium will soon catch fire. This
limits the amount you can make to a few milligrams, and presents an
obvious fire hazard.

3. Lye is very nasty stuff. Molten solutions will dissolve glass (I
found this out the hard way) and will react with aluminum and similar
reactive metals. Many commercial drain openers such as Drano contain
added aluminum granules to melt the fat prior to turning it into soap,
and should not be used because of this.

4. Finally, sodium itself should be treated with appropriate respect. I
bought a pound from Fisher in 1962. It was fun to put little chunks into
water and see it sizzle until the metal caught fire. The last time I did
that, there was almost no wind and the sodium ignited a large cloud of
hydrogen gas that had been liberated by the reaction, causing an
explosion. I ended up peeling a sheet of sodium metal off of my forehead
where it had been splattered by the blast. I feel lucky to still have my
vision after that experience.

Take it from an old fart with experience. There are lots of surprises
that can cost you an eye, hand or worse if you are not cautious when
dealing with reactive chemicals. You can still have fun with them in
relative safety if you know what you are doing, but it takes BOTH
education AND attention to detail. 

Throwing stuff together to see what will happen is fun but stupid, as I
found out when I tried to distill off perchloric acid by boiling battery
acid with potassium perchlorate. Any regular reader of this group could
tell you what happened next. If I had had a resource such as this to
read before starting, perhaps my parents would not have had to replace
my bedroom floor.

Dick Weisiger

P.S. You never get over the desire to do stupid things. You simply have
to overule your stupid urges with an acquired sense of fear.

From: ahahma@utu.fi (Arno Hahma)
Newsgroups: sci.chem
Subject: Re: Extracting sodium metal from NaCl
Keywords: Sodium
Message-ID: <1990Jul27.162627.9599@utu.fi>
Date: 27 Jul 90 16:26:27 GMT

In article <2101@vela.acs.oakland.edu> bbesler@vela.acs.oakland.edu (Brent Besler) writes:
>
>In a crude fashion, you duplicated one of the two main commercial processes
>for producing sodium.  The other uses a mixture of molten calcium and
>sodium chlorides.  Calcium chloride melts at about 770 degrees C, whereas
>sodium chloride melts at 804.  I think they use the mixture since NaCl
>volatizes a little above 804.                                     ^^^^
							            Na


This process will yield a mixture of sodium and calcium. However, the calcium
separates on the bottom, when the molten metal is cooled down to 150 C. The
melt is the poured through a screen to separate small calcium granules. The
calcium can be utilized to produce more sodium, sodium chloride is mixed with
calcium, loaded into a retort and sodium is distilled away under vacuum at
about 1000 C. Of course, all handling of the metals must be carried out under
oil or nitrogen, molten sodium will ignite spontaneously in the air.

Although this process (mostly Down's process) produces calcium as a byproduct,
it is still more efficient than the Castner-process using sodium hydroxide.
Sodium will dissolve in molten hydroxide, migrate to the anode and react with
the water formed there. A typical current efficiency in the hydroxide process
is around 30 %, whereas in the chloride process 90..95 % can be easily reached.

I have made sodium and potassium with the chloride process with a good success,
I think I still have about half a kilogram of potassium left. Making alkali
metals is not easy, however. The metal will float on the molten electrolyte,
and thus the electrolytic cell must be well closed to prevent air from
entering. Then you will get a lot of chlorine gas, about 1,5 times the weight
of the metal in the case of sodium. Just think what happened, if you let some
kg of chlorine to the air vent... Also, you need a lot of current to keep
the bath molten or use an external heater.

ArNO
    2