Sciencemadness Discussion Board

Making Nitric Acid for metal nitrification

RogueRose - 3-12-2016 at 02:42

I'd like to make some nitrates of some commonly available metals but as most people on the board, the most difficult part is acquiring the nitric acid. Metals available are: Cu, Zn, Fe, Pb, Se, Ag, Nd, Mn, Mg, Al, Ti. Not necessarily making nitrate of all though, just some interesting ones.

I currently have access to NaNO3, KNO3 and Ca(NO3)2, all of fairly high purity (min 98% my guess) and I can perform some re-crystalizations if necessary.

Acids available are HCl (31.45% and clear), H2SO4 (93% & ~30% - all pretty clean and all clear) and oxalic acid.

I also have some NaS2O5, sodium bisulfate and 35% H2O2. I can probably find some other chems

I have nothing with which to distill HNO3 so I am going to have to settle for filtration after the nitrate reacts with an acid. I am wondering if that is sufficient for nitrating metals. My thoughts are that once nitrated, allow for evaporation then do re-crystalizations to ensure purity. will I carry over a lot of contaminates w/o distilling? I can filter down to 1 micron and possibly to .22 or .45 if necessary.

So, with what I have listed, what would be the best route to make the HNO3 with what was listed?

Sulaiman - 3-12-2016 at 03:50

I believe that you only need dil. HNO3 to react with metals to form nitrates as conc. HNO3 tends to 'passivate' metal surfaces.

I would
. 'purify' drain unblocker H2SO4 with H2O2 (if required)
. weigh out a suitable quantity of Ca(NO3)2 or tetrahydrate into a flask or bottle and add enough dH2O to form a solution, then slowly add a stoichiometric quantity of H2SO4
heat will promote NOx formation

. or just dissolve the calcium nitrate into dil. H2SO4
(not so good as insoluble sulphate will coat the remaining nitrate particles, dramatically reducing the reaction rate)

you should get just highly insoluble calcium sulfate (plaster of Paris, which forms the dihydrate, gypsum) plus dil. nitric acid.
so just filter for dil. HNO3.

P.S. provided that the calcium sulfate is kept wet, it does not quickly form a hard/solid/insoluble lump.

[Edited on 3-12-2016 by Sulaiman]