KNO3 Purification

[drizzt05]

I tried to purify some KNO3 from stump remover. The brand was Grant's Stump Remover. It consists of white, BB sized pellets with some discolorations. I soaked these in water and the water became very cloudy but the pellets were still solid, I poured off the water and added some more. I boiled the mixture in a pyrex bowl until everything dissolved (I was stirring as well). I let it sit for 5 hours and when I came back there was powder dried along the bowl's sides and edges, and along the bottom there were very defined crystals. I filtered everything out and dried it, then crushed it into powder as best I could without my mill. I melted sugar into the powder and let it cool on some aluminum foil after caramelizing. I shaped the foil around it tightly and lit the tip of the dried mixture. It ignited, created a lot of smoke, and the flame was a purple/pink/white color. I believe it was fairly pure KNO3, unless someone else could help me out?

[DeAdFX]

Grants stump remover is already pretty pure if I remember correctly. Anywho increasing the temperature of water will allow to dissolve more stuff. When you lower the temperature of the solution some of the solute will percipitate out becuase it is not as soluble at a colder temperature. My nitrate has some disccoloration it is of no consequence.

[drizzt05]

Am I wasting the potassium nitrate then? It distills down to much less than, or at least what looks like less than, I had before. It seems to be pure white afterwards with no orange or pink.

[asilentbob]

You will lose some because some will still be dissolved in the water. Generally stump remover or any fertilizer grade of KNO3 is plenty pure for pyro purposes...

[psyco_1322]

Have you even tryed the KNO3 in a comp to see if works or are you just assuming it needs purifiing?

[al93535]

I used to use grants. Its just fine for all pyro purposes. It needs nothing, just mill it up.

If I might suggest, go to lowes and get thier stump remover. It is powdered (although still needs to be milled) However, both brands are about 98-99% pure.

[whitefox77]

I purchased 5lbs of KNO3 from an online supplier for $15, but am concerned about purity. The first batch of KNO3 I bought was "lab quality 99.9% pure", and worked very well, but I paid $12 for 1lb (I've since learned that is a very high price). However, the stuff I have now doesn't seem to be working as well. The mixes I've made with it burn slower, less consistently, and less hot. It also clumps together a lot more than the first stuff I bought.

 

My questions are:

Does the purity of something like KNO3 tend to change from supplier to supplier?

If it is a purity issue, is there a way to purify what I have?

Should I be looking at something else instead of the KNO3 as the cause of my problems?

Could this just be a moisture problem and if so will "cooking" it at < 200°F dry it out?

[jacob]

I purchased 5lbs of KNO3 from an online supplier for $15

Was that with or without shipping? as for the sluggish burn rate and clumping it could be a moisture problem, what did you use it in?

[asilentbob]

Its almost defiantly a problem with your charcoal or integration. Potassium nitrate and sulfur arn't very picky purity wise. But your charcoal type, how carbonized it is, and how well everything is integrated are the major points.

[whitefox77]

Charcoal? Sorry no charcoal. I'm making smoke bombs, not black powder.

 

Without shipping. I bought it here. I purchased some other stuff too, paper tubes, caps, fuse... Shipping total was still only $7