Make Potassium Chlorate: Guide & Tips

[mrjeffy321]

no actually the first

The that could be the problem. What volume of bleach were you boiling? You are likely going to have to boil it much longer than that in order decompose all of the NaOCl and remove a lot of the excess water to make crystalization easier.
Remember, I said I boiled about 1300 mL for several hours down to about 300 - 400 mL. Unless your only using a small volume of NaOCl solution, it is going to take much more than 5 minutes.

 

[rashean123]

oooooooooh, that must be why, does that mean that the crystals that I've been trying to burn are not potassium chlorate and in staid potassium chloride

 

[rashean123]

i boiled about one liter of bleach to about 1/2 and added the chloride

 

[Overflow]

trying to understand things...

Hi all,
i tried to rationalize the proces, correct me if I'm wrong.

Molecular weights:
H20 = 18 uma
NaClO = 74 uma
NaClO3 = 106 uma
NaCl = 58 uma
KCl = 74 uma
KClO3 = 122 uma

1 liter of 5% NaClO
1 liter of water -> 1000gr -> 56 moles of water
i'd guess (correct me!) that this means in a 5% solution there are 53 moles of H20 and 3 moles of NaClO

Thermal decomposition should follow this formula
3NaClO -> 2NaCl + NaClO3

So, every 3 moles you get one mole (122 grams) of NaClO3 and 2 moles (116 grams) of NaCl

We will now need 1 mole (74 grams) of KCl

NaClO3 + KCl -> NaCl + KClO3

Which will give us 1 mole (122 grams) of KClO3

Which isn't theorically too bad, but my calculations differ from those given here ( http://www.wfvisser.dds.nl/EN/chlorate_EN.html#thermal ) as he says to add only 28grams of KCl so i must be mistaken somewhere, but where?

 

[mrjeffy321]

1 liter of 5% NaClO
1 liter of water -> 1000gr -> 56 moles of water
i'd guess (correct me!) that this means in a 5% solution there are 53 moles of H20 and 3 moles of NaClO

The concentration of the NaOCl in the bleach solution is by weight….it is 5% Sodium Hypochlorite by weight, not by moles / volume / ….
If we have 1 kg of 5% bleach, then that means that we have 50 grams of NaOCl and 950 grams of H2O.

 

[Overflow]

The concentration of the NaOCl in the bleach solution is by weight….it is 5% Sodium Hypochlorite by weight, not by moles / volume / ….
If we have 1 kg of 5% bleach, then that means that we have 50 grams of NaOCl and 950 grams of H2O.

Oh, thanks for the clarification.
So the only way to know how many moles of NaClO is to actually weight the bleach?

Another couple questions:

-how do we know when the 3NaClO -> 2NaCl + NaClO3 reaction has completed (all NaClO converted, i don't even know if it's possibile!)

-will all the NaClO3 become KClO3, given enough KCl?

 

[mrjeffy321]

Oh, thanks for the clarification.
So the only way to know how many moles of NaClO is to actually weight the bleach?

Or you could measure the volume of the bleach and calculate its mass using a known density.

-how do we know when the 3NaClO -> 2NaCl + NaClO3 reaction has completed (all NaClO converted, i don't even know if it's possibile!)

-will all the NaClO3 become KClO3, given enough KCl?

It is a pretty safe assumption that the Sodium Hypochlorite has all decomposed after boiling off the large volume of water necessary to complete the procedure. If you start off with 1 liter of bleach, you will need to boil it down quite a bit (much less than half its original volume). This boiling process takes a lot of time usually and while this is happening, the NaOCl has plenty of time to decompose.

NaClO3 is very soluble in water. KClO3 is not very soluble in cold water (only a few grams per 100 mL). In order to form and collect KClO3 you are taking advantage of this difference in solubility. You start out with a solution of NaClO3 which is disassociated into ions (Na+, ClO3-), then you introduce another aqueous solution (of KCl) which contains K+ and Cl- ions. The K+ ions will “see” the ClO3- ions are a precipitation reaction will occur. The K+ and ClO3- will combine to form KClO3 which will quickly saturate the solution and then precipitate out as a solid. In the end, there will still be some small amount of K+ and ClO3- ions left over in solution, plus plenty of Na+ and Cl-, there is nothing you can do about this except try to make the conditions are favorable as possible for the KClO3 precipitate to form.

 

[Overflow]

Or you could measure the volume of the bleach and calculate its mass using a known density.

Known density... uhm, where should i look? :P

It is a pretty safe assumption that the Sodium Hypochlorite has all decomposed after boiling off the large volume of water necessary to complete the procedure. If you start off with 1 liter of bleach, you will need to boil it down quite a bit (much less than half its original volume). This boiling process takes a lot of time usually and while this is happening, the NaOCl has plenty of time to decompose.

Yeah, i boil it to 150ml.
I'd immagine a lower heat (electric plate) would give more time for the reaction to happen than a high heat (gas burner), right?

Two days ago i created my first batch with this method and got something that surely had some chlorate (it burned quite fiercely mixed with sugar) but also a lot of sodium.
So yesterday i went to purify this stuff, with a boil + filter action :)
The weird thing is that the chlorate had deposited on the bottom of the pyrex container and as soon as enough heat was there it started to "explode", with little escapes of oxygen!
Now it seems i just lost all the chlorate, as the white powder that deposited was totally unreactive, my guess is that having not well mixed the chlorate with the water the chlorated decomposed into something else
Ideas?

 

[Squall]

If you are trying to make chlorate i would go the electrolysis way. It might take a little longer and require a some work, but the results you get are a whole lot better thah boiling bleach. i a m actually working on a new cell design at the moment. If you are interested i could share my luck with it.
And remember always be careful with chlorate.

 

[Overflow]

If you are trying to make chlorate i would go the electrolysis way. It might take a little longer and require a some work, but the results you get are a whole lot better thah boiling bleach. i a m actually working on a new cell design at the moment. If you are interested i could share my luck with it.
And remember always be careful with chlorate.

Very interested, sent you PM :)

 

[rashean123]

success!

ive finally got some chlorate when freezing the solution, after weeks of failure i managed to get about 412-414 grams, i tested it with sugar and it made a bright purple flame that seem to flash when i lit, it.is this really potassium chlorate or is it another failurehow i make money for pyrotechnics: http://www.treasuretrooper.com/274150
its free

 

[mrjeffy321]

it made a bright purple flame that seem to flash when i lit, it.

Excellent! Purple is the magic color...it let's you know that you have removed almost all of the Sodium impurities. How many crystalizations did you do to get it to this level, or did it just come out this way on the first try?

is this really potassium chlorate or is it another failure

It sounds like you were very successful. It obviously behaves as KClO3 should and the purple flame indicates the Potassium ion is present without a significant amount of Sodium (the Sodium's yellow color will easily overpower other, weaker, colors like the purple from Potassium).


As long as we are sharing results with each other...
just last week I finished what currently holds the record for my largest electrolytic Chlorate cell to date.
I electrolysized about 800 grams of Sodium Chloride over the course of about 2 weeks to make (theoretically) about 1000 grams of Sodium Chlorate.
When I precipitated out the KClO3 from solution and dried it, I measured its mass to be about 850 grams. Although it is far from the theoretical yield (since there is probably about 100 or so grams left in solution which I cannot easily extract), I am still quite happy with it. it appears to be of excellent quality, although I have not tested it (no need really, I know what it is just by looking at it...I know what the crystals should look like by now). After drying it, I re-dissolved it in boiling water along with a little remaining ("dirty") Chlorate I had sitting around. I precipitated all of this out of solution again and it is currently drying (and will do so for the next 2 months while I am away from home).
This most recent Chlorate cell run has gave me another milestone...I did not have any majors accidents while running it. It seems, as luck has it, I always do something to screw up my cells runs (either knock it over with my hand, connect the electrodes up reversed, ...), but this time everything went reasonably smoothly.

During the run I employed the use of my Amp Hour meter (to measure the charge put through the cell) and a new digital pH probe to make twice-daily pH adjustments. The cathode was a single, threaded, stainless steel rod placed in the center of the lid of a plastic container and was surrounded by Carbon-graphite rods (as the anodes) placed in a 2-layer, circular, pattern around the cathode.

 

[rashean123]

it pretty much came out this way, i thought ide do one last try at it and it finally worked.
wow! 800-1000 grams, what was your cell voltage?, and have you ever had any heat problems? with the cell, and does the cell have to work at a certain temp?, and how do you tell if its sodium chlorate ?, because think it won't burn the same.
lol too many questions

 

[mrjeffy321]

My cell voltage was around 5 volts.

Yes, when running so much current through the cell for extended periods of time a lot of heat does build up. This most recent run cycle was not too bad since I was only consuming about 50 watts or so of power, but never-the-less the electrolyte solution did get warm after a while.
On a previous run cycle I was consuming about 80-90 watts of power and heat was a much bigger problem as much of the plastic/rubber insulation on the wires and aligator clips was melting. At one point, I placed a small resistor into the circuit to help lower the current and dissipate some power. This resistor was not up to the job and practivally burned itself out and overheated. I tried freezing the resistor in a block of ice and then insulating the ice from the cell running environment. After not too long I would come back and check the cell and my block of ice had turned into a pool of hot water.

There is an ideal temperature range to opperate the cell in which the Chlorate production becomes the most efficient. This temperature is somewhere around 70-80 degrees C I think, but precise temperature control is hardly necesary I think. As I said already, the power dissipated by the cell (as it acts like a resistor in the circuit) will keep the electrolte very warm (possibly even too warm).

You know you have produced NaClO3 is you add some KCl to it and get a precipitate. If the precipiate burns when mixed with a fuel (sugar), it is KClO3.
NaClO3 burns in a very similar manner to KClO3.

 

[rashean123]

oh and how much water did u use ?

 

[rashean123]

what power source did you use, like a better charger or...?

 

[rashean123]

oh and thanks 4 the response

 

[mrjeffy321]

The volume of my electrolyte solution was about 2.5 Liters.

As a power source, I used a converted computer ATX power supply. I connected the +5 volt and Ground terminals across my cell.
A long time ago, when I was just starting, I would use battery chargers as a power source, but you cannot draw much current from them without burning them out so I really needed to upgrade to the power supply I have now.

I haven been through many cell designs over the years (I think there is information about this in my Potassium Chlorate thread, maybe). But I need to figure out a better design before I will try to do another run, so it will likely be a while.

 

[rashean123]

ohh, well i have made my chlorate but i will keep it for experimental uses 4 now, considering i do not want anything to go wrong 4 this years fireworks display.

oh and do you make ur own firewors(ball shells, canisters,mines,cakes), or do you buy them.
just wanted 2 know

 

[mrjeffy321]

oh and do you make ur own firewors(ball shells, canisters,mines,cakes), or do you buy them.

Surprisingly...neither.
I am forced to be content with merely watching the city’s firework display when the 4th of July rolls around.

 

[rashean123]

OOOOhhhhh ok