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Chemistry Forums for Students => Inorganic Chemistry Forum => Topic started by: CrtSuznik on April 06, 2019, 06:09:23 PM

Title: Nitric acid from fertilizer???
Post by: CrtSuznik on April 06, 2019, 06:09:23 PM
I'm trying to make nitric acid. The "classic" nitrate salt+HCl+Cu process.

A friend gave me the nitrate in fertilizer form and neither of us even had a clue if it contained nitrates, however I tried making a small batch to see if it works. It didn't generate any visible NO2 gas. At least there didn't seem to be any orange/red-ish fumes in and around the bottle.
Hoooowever gas was being generated (colorless) and the Cu was being eaten up. After some time the solution started turning dark green. A while after that, clumps of a percipitant started forming in the solution. Seemed to be white, but slightly green because of the color of the solution.
I took the clumps out since they started blocking the gas from leaving the bottle and checked if they could be dissolved in water. As expected, they dissolved. I dipped in some Al metal and saw that a brownish powder started forming on it's surface. I'm assuming the powder was Cu and the Al was replacing it in the solution.

I've no clue why I managed to dissolve copper, but seemingly no NO2 gas was formed.
Does anyone have an explanation for this? Also, any idea how I could actually produce nitric acid from the fertilizer that I have or should i just buy some KNO3?
Title: Re: Nitric acid from fertilizer???
Post by: Enthalpy on April 08, 2019, 04:22:53 AM
BEWARE your fertilizer might be ammonium nitrate, and then you are living dangerously.
If you don't know exactly what compounds you use, DON'T try random reactions.
https://en.wikipedia.org/wiki/Ammonium_nitrate_disasters