Sulfamic acid at ambient temperatures

[huggybear]

I planned to use sulfamic acid as an alternative to the boiling down method to deNox.

Turns out when using sulfamic acid you still need to heat the solution to 90℃.

Because I am dealing with large volumes, and heating isn't possible, I'm wondering.. is sulfamic acid is effective at all at ambient temperatures?

 

[eaglekeeper]

I assume you are using heat to dissolve your metal...?

After you remove heat from your reaction, you can (carefully) add it then while it's still hot. Plus any undissolved Sulfamic acid crystals will get filtered out when you filter the solution.

Are you premixing your AR ?

 

[huggybear]

Unfortunately this is a bulk solution that I received from a 3rd party and am trying to treat. They have added excess nitric too which makes my life difficult!

 

[Yggdrasil]

Unfortunately this is a bulk solution that I received from a 3rd party and am trying to treat. They have added excess nitric too which makes my life difficult!

If you can not heat it, you are basically left with two options.
Add sacrificial Gold or Copper to consume the Nitric (weigh the sacrificial metal), or set up a SO₂ generator and bubble SO₂ through the solution.
This will precipitate the Gold which will redissolve immediately and such consume the excess Nitric.
After the Gold has precipitated it may be good to let the SO₂ off gas.
Then re-refine.

The third option is to let it evaporate by itself, but that will take time.

 

[nickvc]

To add to yggdrasils comments I would start by adding some sulphamic, even cold it will convert some of the nitric, following that you can add more material to see if the acid is still reactive or add any precipitant but do so very slowly as the reaction can be violent, maybe take a few small samples and try various ideas to see what works and or happens.

 

[eaglekeeper]

As Nickvc said, you can add it at room temperature and it will work although a little slower.

I forgot to mention.... Using sulfamic acid will convert any lead in solution into a form that can be filtered off. That's why you should add it before filtering.

 

[BlackLabel]

I planned to use sulfamic acid as an alternative to the boiling down method to deNox.

Turns out when using sulfamic acid you still need to heat the solution to 90℃.

Because I am dealing with large volumes, and heating isn't possible, I'm wondering.. is sulfamic acid is effective at all at ambient temperatures?

huggybear,

Please don't double post. It's hard enough to follow your doing in one thread.

https://goldrefiningforum.com/threads/gold-recovery.31786/post-337285

 

[huggybear]

huggybear,

Please don't double post. It's hard enough to follow your doing in one thread.

https://goldrefiningforum.com/threads/gold-recovery.31786/post-337285

Apologies,

I didn't receive a reply so I posted a new thread. As far as I'm aware you can't delete posts in this forum?

 

[Yggdrasil]

Apologies,

I didn't receive a reply so I posted a new thread. As far as I'm aware you can't delete posts in this forum?

We all are here of our good will in our spare time, so answers may take time.