Sodium chlorate-proprieties

Hello everyone!
I wanted to make some KClO3, but getting decent amount of KCl here where I live is close to impossible. Ordering from the internet or "Lo-salt" are somewhat expensive, KCl as water softener is unavailable, KCl as fertilizer is nearly unavailable, while chemical supply shops are non-existent .

So I wanted to make NaClO3. Wikipedia says it is higroscopic and I have a few questions:
-how higroscopic is it?
-can I store it in a jar or plastic bag without serious degradation?
-can I dehydrate it by heating? What temperature will I need?
-are there any other proprieties I must be aware of?

I'm not going to store pyrotechnical mixes, just "pure" NaClO3

Also, I've read I have to remove CrO4^2- before crystalization. Is it true?

Needing chromate in chlorate cells is an obsession imo.

In Ullman. Chlorine Oxygen acids and salts it says

Cathodic Reduction of Hypochlorite. The
main loss occurs by cathodic reduction of hypochlorite,
as described in Section 4.2.1:
ClO− + H2O+2e −→ Cl− + 2 OH−
The reaction competes with hydrogen generation.
Without special precautions, its rate is
controlled by mass transfer and, therefore, linearly
proportional to the hypochlorite concentration
in the bulk electrolyte. The reaction can
widely be suppressed by adding a small amount
of dichromate (1 – 5 g/L) to the electrolyte solution.
By cathodic deposition a porous surface
film of chromium hydroxide forms [169]. Inside
the pores of this film, the effective current density
increases, and the resulting potential gradient
across the film impedes the diffusion of any
kind of anions to the cathode, whereas the access
of cations to the cathode and their reduction are
facilitated. The protective film ceases to grow
after a certain thickness is reached; the increase
in cell voltage caused by the ohmic resistance of
the film is more than compensated by the gain
in current efficiency [165], [170]. Increasing the
electrolyte temperature favors mass transfer of
hypochlorite to the cathode and, therefore, requires
more dichromate. When the current is interrupted,
the surface layer dissolves. It takes
some time to reestablish a new film after the current
is switched on, but cathodic reduction immediately
takes place. Therefore, cells should be
operated continuously, and a minimum cathodic
current density is recommended to prevent dissolution
of the film [171]; from industrial experience,
a current density of 20 A/m2 is considered
satisfactory.

Cathodic Reduction of Chlorate. Chlorate
is also reduced at the cathode, but this reaction
is less significant than the reduction of hypochlorite
described in the preceding paragraph:






Just use a small cathode and cover the side of the cathode that in not in direct line of site to the anode with plastic. The side of the cathode not in direct line of site to anode will have low current density and may be reducing Hypochlorite back to salt.
This method will increase voltage accross cell a wee bit but it will be not noticed by all home producers. Industry could not tolerate this.

LEAVE THE CHROMATE OUT OF THE CELL (so there you have it )

Quote:

Jock88 said: LEAVE THE CHROMATE OUT OF THE CELL (so there you have it ) (...) Just use a small cathode and cover the side of the cathode that in not in direct line of site to the anode with plastic. The side of the cathode not in direct line of site to anode will have low current density and may be reducing Hypochlorite back to salt. This method will increase voltage accross cell a wee bit but it will be not noticed by all home producers. Industry could not tolerate this.

Ask woelen and he will say exact opposite. There just seems to be chromate enthusiasts and opponents.

I'll do some experiments on chromate addition.

Also I can' t cover any part of a cathode-it's completely surrounded by anodes! (With keeping 2cm distance) .


[Edited on 23-5-2015 by MeshPL]

Nice 'gattlling gun' of an electrode system there Varmint.

IMO (for whats it worth) is that you have eliminated cathode reduction.

Most home cells have just the one flat anode + 1 or 2 flat cathodes which (you would imagine) have low CD on the (back) sides away from the anode = cathode reduction of hypo on the 'back sides'


An extreme example of very bad cathode here.

http://oxidizing.typhoonguitars.com/chlorate/cat_size.html


The *AC and **PC camps are in constant battle with each other. Its an entrenched, bitter, long lasting savage battle (let me tell ya).

As a home producer I am inclined to leave stuff out that may possibly interfear with pyro stuff etc down the line. Thats not to say you cannot use and remove chromates. You can. I don't even know if chromates are a problem with pyro stuff if not properly removed.

* Anti chromate
**pro chromate

Quote: Originally posted by dangerous amateur

Is it even possible for hobbyists to produce NaClO3 with a useful purity? Since the difference in solubility of NaClO3 and NaCl are not to great. Most people separate the chlorate by metathesis with KCl, however what if you want the Na salt? Or like the threadstarter, have no KCl?

Quote: Originally posted by jock88

If you keep adding salt solution to the set up solid sodium chlorate will start to appear on the bottom of the cell (just the same as with KClO3 but it takes longer to 'fill up the pipeline'). This can be washed (and recrystallized if you want.) Don't use sodium chlorate in pyro stuff or you will get damaged.

Quote: Originally posted by dangerous amateur

The Acetone process sounds interesting, but Acetone is no longer OTC in the EU.

Sodium chlorate solubility in acetone

I found this:

https://srdata.nist.gov/solubility/IUPAC/SDS-30/SDS-30-pages...

It says that only .1 g will dissolve in 100g acetone. well - I guess Wikipedia has been proven wrong. SMWiki also has the wrong facts..

Could someone confirm?

Feels weird.