# Removing excess nitric acid



## zorba (Mar 17, 2010)

Just wondering if it would be good enough using the sulphuric acid contained in car batteries (around 30%?) when removing the excess nitric acid from the AR solution. Or do i need to get my sulphuruc acid in an other way? What do you guys recommend?


----------



## golddie (Mar 17, 2010)

You have to bring your AR to a syrup but dont over do it.
Add more HCl and evaporate and bring to thick syrup .
In another words you have to evaporate the nitric
The batter acid is for removing lead.


----------



## zorba (Mar 17, 2010)

Okey, so i do not need the sulhpuric acid to remove the excess nitric acid ? I will try without thanks...


----------



## 4metals (Mar 17, 2010)

What are you refining and exactly why are you removing the excess nitric? The nitric can be consumed by digesting additional gold until it is exhausted. Careful additions of nitric when digesting will minimize how much extra nitric you have to deal with. If all you are doing is precipitating gold the nitric can be consumed by using other less tedious ways.

1 you can gas it with SO2, the gold will drop and the excess nitric will re-dissolve it giving off the red cloud until the nitric is exhausted and the gold drops.

2 you can add urea prills until the gassing stops, don't add too much too quickly as it can foam up on you.

3 you can add sulfamic acid just as you added urea (in #2) to kill off the nitric.

Then (in 2 and 3) you can precipitate with your precipitant of choice. 

The triple boil down of nitric is classically used to recover platinum and palladium. The nitrogen complexes must be removed to get complete precipitation. If you're not recovering PGM's in quantity, forget the boil off, kill the nitric, and collect your PGM traces left in solution by cementing with copper.


----------



## zorba (Mar 19, 2010)

4metals said:


> What are you refining and exactly why are you removing the excess nitric? The nitric can be consumed by digesting additional gold until it is exhausted. Careful additions of nitric when digesting will minimize how much extra nitric you have to deal with. If all you are doing is precipitating gold the nitric can be consumed by using other less tedious ways.
> 
> 1 you can gas it with SO2, the gold will drop and the excess nitric will re-dissolve it giving off the red cloud until the nitric is exhausted and the gold drops.
> 
> ...




I appreciate the info, but my main problem is that up here in Sweden it is so hard getting a hand on all those chemicals used when separating, collecting, precipitating e.t.c. So what i want to do is get the gold in all my electronic scrap (mainly motherboards and old ceramic CPU:s) in the AR solution and from there on precipitate. Either with the electrorefining system or copperas. So far, the electro method had not been quite succesfull. The cathode not only catches the gold ions but also the copper and other base metals remaining from the e-scrap. Now the thing is, i am really not so experienced in this so i must as a beginner try out the copperas precipitation method so that i can get a bigger view of the easy steps. And for that i must remove the excess nitric... 
As for the base metals, i have a hard time getting me some nitric acid which is a main problem for many refiners as i have understood? So to remove the base metals i will need nitric acid... Anyway, i am in the middle of a mess were i really need some expertice help. 
So another question for you: When making the AR will it be good enough adding nitric *salt* to the HCI solution? Or is it essential that i have nitric acid? And as i have seen in some videos and read about, when making nitric acid, sodium nitrate is needed but will it be good enough using nitrate salt ?
Appreciate for your time, i hope my english is fairly acceptable...


----------



## butcher (Mar 19, 2010)

poor mans nitric can be made with a nitrate salt sodium or pottassium nitrate and sulfuric acid. 
if silver is your goal distilling would be best here.
poor mans aqua regia can also be made from these nitrate salts.
copperas http://en.wikipedia.org/wiki/Iron(II)_sulfate
can be easily made.
there is alot of information and discussions of these in the forum.


----------



## zorba (Mar 20, 2010)

butcher said:


> poor mans nitric can be made with a nitrate salt sodium or pottassium nitrate and sulfuric acid.
> if silver is your goal distilling would be best here.
> poor mans aqua regia can also be made from these nitrate salts.
> copperas http://en.wikipedia.org/wiki/Iron(II)_sulfate
> ...



Right, i will check into that.


----------



## Harshana552 (Sep 27, 2022)

4metals said:


> What are you refining and exactly why are you removing the excess nitric? The nitric can be consumed by digesting additional gold until it is exhausted. Careful additions of nitric when digesting will minimize how much extra nitric you have to deal with. If all you are doing is precipitating gold the nitric can be consumed by using other less tedious ways.
> 
> 1 you can gas it with SO2, the gold will drop and the excess nitric will re-dissolve it giving off the red cloud until the nitric is exhausted and the gold drops.
> 
> ...


thank you very much sir one of the best explanations for one of my problems in this area.


----------



## lanfear (Sep 29, 2022)

You could just order sulfamic acid of ebay. I ordered to Norway without any troubles. Think i payed 20 $.


----------

