Petit Homme
Harmless
Posts: 23
Registered: 6-5-2025
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HNO3 from KNO3 + NaHSO4
I'd like to make a small amount of HNO3 (less than a beaker full should be enough for my needs, though I could be interested in doing a bit more for
cleaning glass).
I know that HNO3 production has been discussed as nauseam on this forum and I've read through a lot of it. I haven't found a thread dedicated to this
specific route however, so here it is.
All I have is KNO3 and NaHSO4 (and a very very tiny amount of very clean H2SO4).
I know this is probably not the most comfortable method but after the – most likely well intended for many reasons beyond the understanding of a
non-twisted mind – ban on H2SO4 in the EU at least these two are widely available to all at reasonable prices.
What I'd like:
Fair enough (i.e. at least not catastrophic) yields
Safer is better
Not cracking my glass would be great
Not spending tons of time on executing the process would be great too
Anything above 20-50% HNO3 as a product is good (I'd re-distill it afterwards anyways for purity)
A few questions regarding this method here below:
1) Does anyone have a process for this route?
2) Has anyone successfully performed this on a large enough scale?
3) What are reasonably yields to expect from this?
4) Is it better done dry or is it okay to add water to increase yield and minimize offgasing fumes (being fine obtaining a product at lower
concentration)?
5) Could adding a small amount of H2SO4 (say 1-5% NaHSO4 amount) of to the mixture help, as a sort of catalyst?
6) Should I go with a large excess of NaHSO4? (its 4x cheaper than the KNO3) Would this help prevent caking?
7) Any reasonable way I can use a vacuum pump on this without ruining it (one washing bottles with water and tiny amount of H2O2 to catch fumes into
dilute HNO3, one with a mild base, and one with plain water before the pump)? Or do I need the high temperatures for the reaction?
8) Any tips for this lovely endeavor?
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macckone
Dispenser of practical lab wisdom
Posts: 2211
Registered: 1-3-2013
Location: Over a mile high
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Mood: Electrical
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Adjust the stoichiometry for potassium instead of sodium nitrate. Follow nurdrage's procedure.
His nitric acid Playlist is definitive.
nurdrage playlist
[Edited on 11-10-2025 by macckone]
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