Moisture problem in my new batch of potassium nitrate

[Uarbor]

I have read a bunch of threads regarding drying potassium nitrate in the oven at various temperatures. I'm not in any hurry would a drying box or food dehydrator dry it enough? Or does it really need that much heat? I put some out in the sun in a baggie and the baggie is fogged up already.

[MadMat]

Food dehydrator should work just fine.

[SharkWhisperer]

I have read a bunch of threads regarding drying potassium nitrate in the oven at various temperatures. I'm not in any hurry would a drying box or food dehydrator dry it enough? Or does it really need that much heat? I put some out in the sun in a baggie and the baggie is fogged up already.

Grind it in a coffee grinder to dust if it's in crystalline form and dump it onto a rimmed cookie sheet. Oven cook it at 200-300F for an hour and voila! It's dry. Mix it around halfway through if you've got a thick pile. Crack the door the last 10 minutes to let any water vapor out. That's with an electric oven. Simples.

 

If you have a gas oven, burning gas makes water, so cook your nitrate for a half hour or so at 300, turn the heat up to 400 to get it good and hot, crack the door slightly to release water vapor, close oven, turn off oven to stop water production, and let it cool down until your powder is at handling temperatures. Voila!!! Dry nitrate! No worries about it decomposing at those low temps.

 

Do the same for strontium nitrate, too, which is a lot more hygroscopic than potassium nitrate is. If your BP is clumping up in the mill, your first consideration should be that your charcoal is probably damp--it loves water and can hold a whole lot of it (wayyy more than KNO₃) and still feel completely dry to the touch. Cook your charcoal the same way as nitrate. Use desiccants for storage.

 

In a food dehydrator, you're probably stuck with low temps and how are you going to easily contain it on those shelves? Hmmm. I have a dehydrator, but an oven's always just been less of a hassle.

Edited May 26, 2021 by SharkWhisperer

[pyrodivision]

I don't have electric oven, I usually makes electric cooker, is it the same?

[MadMat]

In a food dehydrator, you're probably stuck with low temps and how are you going to easily contain it on those shelves? Hmmm. I have a dehydrator, but an oven's always just been less of a hassle.

I think I mentioned this in an earlier post, but in case you didn't see it; I lined the shelves of my food dehydrator with fine (approx. 100 mesh) SS screening, I know this may be a tough order for some to find. I got my screening as surplus from a company that made heat exchangers. I guess it was for an air prefilter. Also, my food dehydrator also came with plastic disks that one could line the shelves with. They had turned up edges and would work perfectly for anything too fine to be contained by screening

Edited May 26, 2021 by MadMat

[SharkWhisperer]

I think I mentioned this in an earlier post, but in case you didn't see it; I lined the shelves of my food dehydrator with fine (approx. 100 mesh) SS screening, I know this may be a tough order for some to find. I got my screening as surplus from a company that made heat exchangers. I guess it was for an air prefilter. Also, my food dehydrator also came with plastic disks that one could line the shelves with. They had turned up edges and would work perfectly for anything too fine to be contained by screening

Your dehydrator sounds perfect for drying stars and other flammable tangible items. Never had a need to force-dry BP granules, even in winter (super low humidity). But seems to me for single-chem drying, especially at higher temps that a dehydrator might struggle to/not achieve, an oven with a big fat rimmed cooking sheet would be the simplest approach. Especially for airfloat charcoal, which would pass right through your 100-mesh screen and make quite a mess of your system. My KNO₃ is also milled pretty finely and a decent fraction might also pass a 100-mesh screen. Hmmm, a little charcoal residue + some nitrate residue tucked together in the recesses of your dehydrator? Think I'll stick with the oven for those chems. But dehydrators are the bomb for helping dry stars and comets!