Idea for sulphurless BP. Feasible? Safe?

[JTO]

Sulphurless BP seems to be a pretty lame mixture, hard to ignite, slow to burn. But H3, which is the exact same composition with a different oxidizer, is anything but. Why can't one make sulphurless BP where some of the KNO3 is substituted with KClO3, you could even adjust the ratio to make it as lame or as aggressive as you like? It is such a simple idea that it must have been tried already, right? Does it have any issues which would make it unfeasible or unsafe?

[Arthur]

But having some chlorate it would be just as difficult as having all chlorate

[JTO]

But having some chlorate it would be just as difficult as having all chlorate

Do you mean that partly substituting the nitrate (slow and lame) with chlorate (fast and aggressive) would not make the composition faster? What would be difficult about it?

[Arthur]

No, difficult as in having chlorate with all the incompatibilities.

[JTO]

I still do not understand. Isn't sulphurless BP just KNO3 and charcoal? In the enhanced version which I proposed you would have KClO3, KNO3 and charcoal. What would be incompatible about that?

No, difficult as in having chlorate with all the incompatibilities.

 

[itwasntme]

H3 isn't just the "same composition" with a different oxidizer, it's an entirely different composition with different characteristics such as you've pointed out.

 

The difference is primarily due to the endothermic vs exothermic decomposition of the oxidizer.

 

Diluting the KClO3 with some KNO3 will likely allow you to somewhat control the burn speed, and I have no doubt that has been done. It may not be worthwhile or simply not published.

 

The reason many avoid KClO3 is for it's incompatibilities with other chems and it's sensitivity.

[pyrokid]

I have tuned the performance of H3-like mixtures with an oxidizer mixture KNO3-KClO3. It generally worked as you might as expect, and I used it to lift small comets.

 

Arthur is referring to the standard chlorate incompatibilities that you might encounter once you construct a device with your special H3 powder.

 

I think the reason that such compositions don't receive much attention on the internet message boards is that alternative approaches work better and cost less. For many, it is easy to make normal black powder. Why would they introduce a more sensitive, less predictable composition when black powder does the job? I would rather make stars with my KClO3.

[JTO]

My rationale is this. If you have chlorate in your stars, or in your primer, you might not want to use BP as burst charge, because it contains sulfur, which does not go well with the chlorate. So, you might use sulfurless BP, which is just KNO3 and charcoal. But sulfurless BP is really lame and slow. Therefore, why not boost it by replacing *some* of the KNO3 with KClO3, and this way you could get a sulfurless composition which works just like regular BP? Perhaps only a fairly small percentage of KClO3 would do the trick?

Why would they introduce a more sensitive, less predictable composition when black powder does the job? I would rather make stars with my KClO3.

 

[sefrez]

The problem with this is based on the assumption that even small or "trace" amounts of KClO3 is incompatible with sulfur. Based on that your not solving any problems. Your just adding another layer of a chlorate containing composition. Will it lower the likelihood of something happening? Probably. But how much?

 

A solution would be to have a sulfur AND chlorate free barrier. Perchlorate would work. If your already making chlorates, perchlorates require more work and care, but maybe you should look into that. If you use it only for instances like this, you would need to be making loads. You don't "need" a lead dioxide electrode, I don't use one. Platinum does work. Platinized titanium electrodes are not that expensive. Are you able to get those?

[sefrez]

"Wouldn't need to be making loads"

 

Can't edit on my phone.

[JTO]

Sefrez - Do you know if it is feasible and safe to convert KClO3 to KClO4 at a home setting? I think I have seen it mentioned somewhere.

[mabuse00]

Dr Liptakov did some interesting examples on this. Search him on YT.

Decomposition of sodium chlorate with heat and making use of the perchlorates solubility in acetone.

 

But that's for small scale experimentation, for practical pyro stuff you will have to go the electrolytic way...

[sefrez]

Sefrez - Do you know if it is feasible and safe to convert KClO3 to KClO4 at a home setting? I think I have seen it mentioned somewhere.

 

 

I make it on small scale. Safety wise, of course. You just need to know what your doing. The main two issues new with perchlorate synthesis is anode corrosion (if you are going by electrolysis) and removal of trace chlorates. You can make chlorates easily with many types of electrodes. MMO appears to be the best. An iridium / ruthenium or iridium / tantalum (what I use now) oxide based one appears to be common. I can pump out around 200g of KClO3 in just over two days on my small 1.3L cell setup. Current efficiency is still in the typical crappy range around 50% without the additions of compounds to control ph. But the process is trivial this way and so I don't complain. This is straight electrolysis of a KCl solution. You can start with NaCl forming highly soluble NaClO3 and then performing a metathesis reaction with KCl to get the KClO3. But why bother with that and having to remove sodium contamination if you can just start with KCl? I've found the electrolytic process of KCl to be at least as efficient as that with NaCl.

 

With perchlorates however, you usually do start with the highly soluble sodium based salt, NaClO3. The ClO3- / chlorate is oxidized at the anode to ClO4- / perchlorate, giving the highly soluble NaClO4. After removal of any chlorate from the perchlorate containing solution, a metathesis reaction with KCl is done to precipitate KClO4. You don't typically start with KClO3 because it is itself low in solubility, and the formed KClO4 extremely low in solubility. So you wouldn't be able to effectively convert your KClO3 to KClO4. But if you can make KClO3, you should be able to make NaClO3. As far as I know, if you use thermal decomposition as mabuse00 mentioned with KClO3, giving you a mixture of K - ClO4, ClO3, Cl, you won't be able to use acetone as a solvent for separation. It works for the sodium salt because NaClO4 is reasonably soluble in acetone where the others are hardly.

 

The only two electrodes that I know of that work reliable enough to consider for perchlorate production are platinum and lead dioxide based. Lead dioxide is consistently said to be the best, but I don't like dealing with lead compounds and so have chosen up to now to not use it and instead use platinum. Platinum is expensive and so you typically have a valve metal (i.e titanium) as the means of primary electron conduction and a layer of platinum at which its surface performs the electrochemical oxidation reactions.

 

You can't simply use platinum in a perchlorate cell like you would MMO in a chlorate cell. It can still corrode and so there are different things you do to help prevent that. The chlorate / perchlorate thread in the chemistry section is huge and has a lot of exchange about perchlorates. Among searching the web, I have found it useful.

 

The creation of perchlorate effectively is probably the most difficult part. Purification is pretty simple (just annoying and takes some more time.) You need to chemically destroy any chlorates remaining (of which one of the parts to producing perchlorate effectively is to not have to destroy / waste much chlorate.) I wouldn't rely upon recrystallization or solvent separation (i.e acetone) alone to separate the perchlorate/chlorate.

Edited September 27, 2021 by sefrez

[Arthur]

ALL the processes for making perc need the use of sodium salts to get the solubility high enough to preserve mmo or Pt electrodes for a reasonable life. Then you add just too little KCl solution to ppt out KPerc and leave the KClO3 in solution. Reuse the solution for the next run after taking the product off rinsing it and drying it.

It doesnt matter that you send a little bit of perc back to the cell, you will harvest it all later.

[JTO]

ALL the processes for making perc need the use of sodium salts to get the solubility high enough to preserve mmo or Pt electrodes for a reasonable life. Then you add just too little KCl solution to ppt out KPerc and leave the KClO3 in solution. Reuse the solution for the next run after taking the product off rinsing it and drying it.

It doesnt matter that you send a little bit of perc back to the cell, you will harvest it all later.

I use carbon electrodes. They corrode very quicky but cost almost nothing, and I have developed a pretty good method of getting the carbon particles out of the final product and from the electrolyte. I have been running my KClO3 cell for at least 6 months now using this setup. I do not add anything but KCl to my electrolyte.