Shalashaska
June 24th, 2007, 12:39 AM
This method of purification of HNO<sub>3</sub> struck me as one of the more simple and less dangerous ways out there, since there is no distillation, and thus, no NOx. But since this method has been but vaguely mentioned by NBK2000 about five years ago, in 2002, I have a couple questions.
1. First of all, I'm guessing that for this to work, the HNO<sub>3</sub> must be impure with NOx, and not water, since water would freeze right along with the nitric. Or would there be fractional crystallization, and the HNO<sub>3</sub> would precipitate out as the water is frozen?
2. Should the dry ice be plopped right into the nitric acid, or put around the container it's in, kind of like a CO<sub>2</sub> bath.
3. Should the HNO<sub>3</sub> be a minimum concentration, or theoretically could you do this with 20% if you had such a horrible concentration.
4. In NBK's posts about it, he mentioned use of methylene chloride; is this a necessary component of this process?
Note: I know that the HNO<sub>3</sub> should be as cold as possible, to prevent sublimation on contact, but that's about all I know for sure about this procedure.
Please excuse my complete lack of knowledge about this, but its only mentions have been rather obscure.
Edit: After finding the actual "Methylene Chloride" thread, I realize there was much more information on this subject than I previously believed. When I read it earlier, it was the archive version and there was only one page.
1. First of all, I'm guessing that for this to work, the HNO<sub>3</sub> must be impure with NOx, and not water, since water would freeze right along with the nitric. Or would there be fractional crystallization, and the HNO<sub>3</sub> would precipitate out as the water is frozen?
2. Should the dry ice be plopped right into the nitric acid, or put around the container it's in, kind of like a CO<sub>2</sub> bath.
3. Should the HNO<sub>3</sub> be a minimum concentration, or theoretically could you do this with 20% if you had such a horrible concentration.
4. In NBK's posts about it, he mentioned use of methylene chloride; is this a necessary component of this process?
Note: I know that the HNO<sub>3</sub> should be as cold as possible, to prevent sublimation on contact, but that's about all I know for sure about this procedure.
Please excuse my complete lack of knowledge about this, but its only mentions have been rather obscure.
Edit: After finding the actual "Methylene Chloride" thread, I realize there was much more information on this subject than I previously believed. When I read it earlier, it was the archive version and there was only one page.