Drying hygroscopic chemicals just by milling them?

[Potassiumchlorate]

Earlier I have found out that copper(II)chloride, which with crystal water is blue, simply turns white, i.e. loses its crystal water, by milling. It now seems that my ammonium perchlorate, which was slightly acidic before, has turned neutral after milling it for several hours. It seems that milling is enough to make water and some acids to simply evaporate from some salts. Or am I totally wrong here? But where then did the water in the copper(II)chloride go, and how did the ammonium perchlorate turn neutral? Edited May 9, 2012 by Potassiumchlorate

[Mumbles]

What you've observed might be a real phenomenon for AP (or there is basic residue from the milling media being incorporated), but you're off base with the copper (II) chloride. I can't properly explain the physical phenomenon, it has something to do with refraction and diffraction of light of fine particles, but I can tell you that nothing has physically changed. Anhydrous copper (II) chloride is brown. The same thing happens with copper (II) sulfate, though anhydrous that is actually white so it can be confusing.

[Potassiumchlorate]

Well, the copper(II)chloride was milled in a small electric coffee mill, and the metal inside the coffee mill was actually coloured brown, so some kind of reaction might partly have taken place, i.e. some chloride but not all might have been made anhydrous or maybe reacted chemically with the metal in the coffee mill.

 

The AP was ballmilled, and the milling media was stainless steel. It looks exactly the same as before the milling but it doesn't smell of chlorine any more and it doesn't give a sour reaction on an indicator paper.

 

From what I have read about AP it has no crystal water and is not hygroscopic "for real" so to speak but might "trap" water inside its crystals anyway.