rift14 - 25-11-2004 at 03:20
I have some fertiliser that contains 7.7 percent KNO3, it also contains urea and ammonium sulfate. I am planning to use it to synthesise HNO3, I asked
some people on APC about synthesising HNO3 with it, and they told me all the HNO3 formed will nitrate the urea. I then suggested ading more sulphuric
acid to make the urea nitrate form HNO3 again. They then called me lazy for not searching further than the hardware store across the street. It
doesn't matter if I'm lazy or not as long as I can get nitric acid. any help would be appreciated.
[Edited on 25-11-2004 by rift14]
chemoleo - 25-11-2004 at 05:37
No, what you suggested is true.
Add a large enough excess of H2SO4, and you will get HNO3. Urea sulphate is then formed, and ammonium bisulphate. You can distill off the HNO3 at
preferably reduced pressure, around 80 deg C.
Don't expect great yields, and expect to invest 10x more H2SO4 than the HNO3 you get out of it.
Not very efficient. You might want to find a different fertiliser.
HNO3 - 25-11-2004 at 08:18
IIRC, ammonium sulfate is insoluble in water. I'm not sure, but you might be able to mix the remaining solution with an excess of ethyl alcohol
and precipitate the KNO3. BTW, why do you want the nitric?
neutrino - 25-11-2004 at 09:59
You have ammonium sulfate backwards. It is soluble in water and insoluble in alcohol.
I would try fractional crystallization, but, with all of those ions (and urea), that might get tricky. If your nitrate concentration is really as low
as you say, though, it might be benificial to remove most of the contaminations by fractional crystallization.
Fractions
MadHatter - 25-11-2004 at 16:38
Depending on how much (NH4)2SO4 is in that mix, fractional crystallization may be more
trouble than it's worth. K2SO4 has the lowest solubility of possible compounds that could
come out and likely to precipitate out 1st. If possible I'd find something with a higher
concentration of nitrate. If unobtainable, then what you suggested in your opening post
may be your best option.
Solubility data per CRC 52nd Edition(1971-1972):
K2SO4 12 @ 25 C / 24.1 @ 100C
KNO3 13.3 @ 0C / 247 @ 100C
(NH4)2SO4 70.6 @ 0C / 103.8 @ 100 C
NH4NO3 118.3 @ 0C / 871 @ 100C
This is grams per 100ml H2O.
Solubility data for urea from an online MSDS is 119 @ 25C.
[Edited on 26-11-2004 by MadHatter]
vulture - 26-11-2004 at 09:13
We don't allow this kind of discussion (if you have any clue about chemistry you wouldn't be asking this) and it's getting way too
practical.
Closed.