# Sulfamic acid to kill excess nitric acid - VIDEO



## kadriver (Apr 14, 2019)

In this video I demonstrate how to rid a gold solution of excess nitric using sulfamic acid.

It was a large lot of gold (for me) and I over-shot my nitric additions while dissolving the gold sponge.

The video is kind of long, but you can go to the 47 minute mark to see the sequence with sulfamic acid.

At the 41 minute mark I break a glass funnel full of boiling dilute nitric acid - serious pucker factor!

Here is the video;

https://youtu.be/epl74FE6l0s

Thank you!

kadriver


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## rickzeien (Apr 14, 2019)

Very nice! Thanks

Sent from my LG-H872 using Tapatalk


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## cuchugold (Apr 17, 2019)

Very nice bar KA. :G


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## Simonides (Mar 23, 2021)

VERY VERY VERY GOOD GOOD GOOD, I never imagined that I could precipitate regal water with ice and adding sulfamic acid to neutralize the acid and in the metabisulfite sequence, for me the precipitation could only be done at 90 ° I was wrong. I still need to learn a lot.


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## Goldenrod757 (Apr 13, 2021)

Does the presence of excess HCl present any issues? A lesser concentrated batch of gold chloride was treated with sulfamic acid and then sodium metabisulphite and resulted in a blue solution and the gold preciptate..normally i use heat to drive off nitric and the end solution is typically green. However when i tried to repeat the process with a more concentrated batch, i have some deposition of gold and the solution remains yellowish green and dark. One small batch was separated and the brown powder left standing redissolved. Could excess HCl present be a hindrance of going to completion or should i continue addition sulphamic and metabisulphite?


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## Lino1406 (Apr 13, 2021)

Sulphamic acid is added until fizzing from nitrous gas ends. After that no more is needed - useless


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## rickbb (Apr 16, 2021)

The color of the solution is more an indication of the base metals content and concentration. Not acid or gold content. 

Don't judge results on color, as stated add sulfamic until fizzing stops, check for gold in solution with stannous regardless of solution color.


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