Is it compulsory to denox nitric acid to recover gold?

[Uciocciu]

Hi guys,

Is it compulsory to denox nitric acid to recover gold ?
On internet videos, I have seen many home refiners dropping gold with smb, without using urea first.
I am just a baby refiner, so iwould like to get your opinion.

Thank you for your responses,

 

[nickvc]

If you are using AR then removing the nitric is usually needed to allow the gold to precipitate because if you have an excess of Hcl then the gold will redissolve until all the nitric has been used up, it also releases noxx which is toxic unless you use a fume hood.

 

[Uciocciu]

Thank you so much for your quick and precise response.

U ciocciu

 

[Geo]

The easiest way to ensure you do not need to remove free nitric acid is to be very careful not to add more than is needed when dissolving the metal.

 

[onebigwinner]

am trying to process flatpack chips all seemed fine until addition of urea no reaction is it possible to buy bad urea I put a drop of solution onto a drop of diluted baking soda and got a reaction indicating acid not neutralized. currently solution has an emerald green clear top layer and a 1 inch layer of white on bottom that has over the past hr turned purple at a loss and don*t want to loose batch

 

[butcher]

Urea will not help when you have nitric acid in solution, it will just form urea-nitrate which leaves nitrate salts, which are easily re-acidified back to nitric acid with HCl acid.

Baking soda will neutralize acid and can form metal carbonates, and will begin to make salts of the acid you need.

The purple color. possibly gold in colloidial form, possibly from tin...

Where did you learn to make a mess like this?