Monk,
Weren't there some perchlorates in older Goex due to the quality of the stock they were using? Not trying to start an argument, as I am just curious, but I remember reading that here I think. If so, wouldn't it possibly make the powder a little snappier (as well as more corrosive)?
Not perchlorate.
Vicksburg Chemical Company produced potassium nitrate by reacting potassium chloride with nitric acid. That plant went into production around 1968. Constructed specifically to produce a cheap fertilizer grade of potassium nitrate. The potassium chloride "feed stock" came out of the salt mines in the Carlsbad, NM area. The salt deposits in that extensive formation are in layers. One layer would be mainly potassium chloride with the layer next to it being sodium chloride. They separated the salts using a flotation process similar to that used in copper ore concentration. Using a type of soap that was supposed to only attract to the potassium chloride. But there was some carry over of sodium chloride in the potassium chloride.
So the "feed stock" used by Vicksburg had a small amount of sodium chloride (roughly 0.5%) in with the potassium chloride. So in the conversion process the sodium chloride was converted to sodium nitrate. About 0.5% of sodium nitrate in the finished product. Really messed up the hygroscopic properties of the potassium nitrate.
The particular conversion process used by Vicksburg was not a 100% conversion process. Under normal reaction rates the conversion of potassium chloride to potassium nitrate was about 97 to 98% efficient. So there was always a percent or two of potassium chloride going through the system un-reacted and into the finished product.
ANY chloride contained in the potassium nitrate will result in a more corrosive powder residue in the gun. Remember. The potassium carbonate (pot ash) produced by powder combustion is in itself slightly corrosive. Promotes surface rusting in the bore but NOT pitting of the metal. Chlorides will not only rust the steel but will also cause pit corrosion of the bore.
The presence of 1 or 2% of potassium chloride in the potassium nitrate sort of takes away from powder combustion since it carries no oxygen. Just ends up as minute crystal scattered over the surfaces of the bore. Given a little bit of moisture these crystals set up what might be called ideal chloride pit corrosion sites (cells).
I started telling GOEX that back in 1984. As a result they threatened to sue me numerous times. but then in 2000 when they had to change to the potassium nitrate made in Chile they quickly realized that I was correct in what I was telling them. But for 28 years they were paying for a technical grade while being shipped a fertilizer grade.
If you look back in the original Lyman Black Powder Handbook, copyright 1974, you see a write up of the GOEX Moosic, PA powder plant. When they get into the potassium nitrate subject they comment that they screened their potassium nitrate to remove sticks and stones. The presence of these sticks and stones were the "proof" that it was indeed a fertilizer grade.
The so-called "sticks" were bits of wood from their wooden processing and storage tanks. The so-called "stones" were bits of gravel that had originally been in the potassium chloride "feed stock" at Vicksburg Chemical. Having gone through the conversion process and ending up in the beaded potassium nitrate.
Now if you are spreading this fertilizer grade potassium nitrate on a field the "sticks" and "stones" are no big deal. But in black powder you better get them out or you will blow up wheel mills on a regular basis.
I purchased a 40 pound bag of Vicksburg Chemical potassium nitrate at a local roller mill when I was looking at all of this. In addition to the sticks and stones there was a good bit of clay in the beads of potassium nitrate. More debris carried over from the salt mine flotation process and right through the powder making process.
When I took a pound of this source into work I dissolved it in water. Filtered out all of the water-insoluble junk and found that it was at best about 95% pure. NOT the 99.5% purity level that was being claimed for it.
E. Ogre