When to stop adding nitric

[MvK]

Hi guys,

Im currently getting rid of all my previously processed ceramic stuff. This is mostly from when i began recovering gold without heat and a proper fumehood. I discovered some CPU that still had solder and brazing under the silicon chip.

Before i finally get rid of them im giving them one last swim in AR. They are currently boiling away, and i am patiently adding nitric acid with tiny doses to prevent boilovers. I know it takes alot of time to digest the brazing under the silicon.

The thing is, because the process is very slow there are almost no brown fumes showing the nitric is working. When i add some drops of nitric there is some violent foaming going on in there. But now im not sure if im adding too much nitric because of the lack of fumes..

Long story short, how do i know when to stop adding nitric acid to my mixture?

Thanks,

MVK

 

[Yggdrasil]

Hi guys,

Im currently getting rid of all my previously processed ceramic stuff. This is mostly from when i began recovering gold without heat and a proper fumehood. I discovered some CPU that still had solder and brazing under the silicon chip.

Before i finally get rid of them im giving them one last swim in AR. They are currently boiling away, and i am patiently adding nitric acid with tiny doses to prevent boilovers. I know it takes alot of time to digest the brazing under the silicon.

The thing is, because the process is very slow there are almost no brown fumes showing the nitric is working. When i add some drops of nitric there is some violent foaming going on in there. But now im not sure if im adding too much nitric because of the lack of fumes..

Long story short, how do i know when to stop adding nitric acid to my mixture?

Thanks,

MVK

You never boil a solution with PMs.
As the bubbles burst they expel droplets all over and you will loose Gold.
70-90 Centigrade is plenty.
And then you will see the tiny bubbles forming where the reaction is in the liquid.

 

[MvK]

You never boil a solution with PMs.
As the bubbles burst they expel droplets all over and you will loose Gold.
70-90 Centigrade is plenty.
And then you will see the tiny bubbles forming where the reaction is in the liquid.

Usually i am not that stupid, this time i turned up the heat to try to get fumes..

Lesson learned, thank you master!