Nitric Freeing Methods (excluding evaporation)

[Shark]

Heated maybe, but boiling isn’t necessary.

 

[huggybear]

The metal of choice for cementation of PGM's is copper, depending what the other metals in solution are, zinc may drop a lot of undesirable metals leaving you with a mess that isn't close to refined. Copper drops only PM's.

That is why you have been asked what the source is, but if you don't want to answer you may have to deal with the mess.

I checked out the reactivity series for metals and noticed that copper is below hydrogen, so it won't displace hydrogen from acids to produce hydrogen gas.

If this is the case, what side reactions are taking place (assuming I have HCl and sulfuric acid after I deNOXed using sulfamic acid)?

Thanks

huggybear