As I understand, HNO3 can be made with a nitrate salt and sulfuric acid or hydrochloric acid.
But when you use HCl, the distilled HNO3 will contain unknown amounts of HCL... Is there any way to prevent this contamination or to separate the
acids?
I need nitric to dissolve gold bearing materials but I really don’t want to dissolve the gold at this point. Is sulfuric acid the only solution or
can I achieve this with HCL/nitrate?
Both nitric and sulfuric acid are really hard to find where I live.
HCL on the other hand is an unregulated chemical. APO - 14-2-2013 at 11:16
I don't think so , once they're mixed they form aqua regia.Vargouille - 14-2-2013 at 11:19
You can't separate by boiling, because nitric acid and hydrochloric acid decompose to nitrosyl chloride upon heating. What you could also do is add
the nitrate of a metal with an insoluble chloride. Lead nitrate is probably the cheapest, but it doesn't work very well. Silver and mercury nitrates
would work better, but they're more expensive/ harder to find/ more dangerous.
Personally, I would just bite the bullet and go the sulfuric acid route. AndersHoveland - 14-2-2013 at 15:14
There is actually an equilibrium. Under more concentrated acidic conditions, the equilibrium shifts away from the nitric and hydrochloric acids.
The equilibrium in concentrated solution can be rather complex, and even includes nitrogen dioxide.
I am not entirely sure about distilling them together. You could probably separate out the HCl if the acid mixture was very dilute. Otherwise the
equilibrium would probably result in the volatile products distilling out, and then condensing back into nitric and hydrochloric acids in the
receiving flask.vmelkon - 16-2-2013 at 18:12
Both nitric and sulfuric acid are really hard to find where I live.
Sulfuric acid is in every car battery. Get some old car batteries and charge them first, then distill to concentrate it.
When I measured mine, it was 19% H2SO4 and distilling gets rid of a lot of volume of water, and I ended up with about 6 M H2SO4. I did not concentrate
it further.
Some people buy CuSO4 and do electrolysis with 2 graphite rods to remove the copper. In my opinion, this isn't great because it will always contains
CuSO4. But then again, the battery acid has some PbSO4.AJKOER - 17-2-2013 at 07:02
OK, do not do anything.
Your aqua regia is want you need for dissolving gold. By themselves, H2SO4, HCl and HNO3 even if concentrated, do not dissolve Au.
