Electro nitric acid

[Arthur]

Reading an old (ca 1900) text, a method for the electrolytic production of nitric acid from the nitrate content of the natural groundwater in a peat soil was discussed. It was said to be a permanent process because the natural action of nitrogen fixing bacteria continued, keeping the raw material -nitrate, flowing steadily.

 

 

Following from this and the electro perc thread(s) is there a viable means of getting nitric acid from a nitrate salt by electrolysis?

[tentacles]

There would be a point where the nitric acid content would be enough to overcome the electrolytic plating - after a while, the nitric would be dissolving the metal back into solution as fast as it plated out. So you'd never get pure nitric, at least not without distilling the solution.

 

It would only work with metal salts that you can plate out in solution - ie no akali metals. So you'd have to start with an expensive nitrate salt (copper, lead, iron, what have you) and STILL have to distill the solution - and get at most 68% conc.

[Picric acid DOES taste bitter!]

I tried to make ammonium nitrate via electrolysis once...Still not sure how it worked out since my graphite electrodes corroded and left a blak sludge in the glass jar....

 

Anyway, I used an aluminum foil cathode (to absorb the NaOH) along with graphite in an solution of 20% NaNO3 dissolved in an 30% ammonia solution.

 

Theory:

The NaNO3 and water forms NaOH, wich is absorbed through the aluminum, and HNO3 wich instantly reacts with the amonia to form AN.

 

The problem was, the mix got really hot quickly (kinda as I hoped, since I thought the heat was comming from the HNO / NH4 reacting) and evapourated most of the ammonia. I only ran my "cell" for about 3 hours. Then I filtered the mix to separate the sodium-aluminate hydride (i think that is what forms) and boiled off the water from the filtered solution.

 

This solution definatly still holds some NaNO3, but what do you guys think? Did i have some AN?