# PPT silver from Silver Nitrate ?



## grainsofgold (Jan 27, 2017)

I've been reading some older books on silver- 

One mentions that Ag can be PPT from Silver Nitrate with Hydrogen gas if the Silver Nitrate is heated some and can be dropped from Cold Silver Nitrate if done with Pressurized Hydrogen - 

Not that I want to try this - but I am curious about this process and what purity of the PPT silver would be ?

Thoughts ?

Thanks


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## Lou (Jan 27, 2017)

It's called pressurized hydrogen stripping. Works with all of the noble metals to varying extents.

Any metal theoretically reducible by hydrogen (i.e. Cu, Ni)can contaminate.


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## Lino1406 (Jan 28, 2017)

I think you should consider side reactions like NO2 formation


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## grainsofgold (Jan 28, 2017)

Thank you - 

It was mentioned in a book on Gold, Silver and Copper Chemistry


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## Lou (Jan 29, 2017)

Lino1406 said:


> I think you should consider side reactions like NO2 formation





Depending on the pressure, it may be ammonium cation as product.

For instance, borohydride reduction of Pd nitrate solutions gives Pd metal and ammonia.


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## upcyclist (Jan 30, 2017)

Lou said:


> Depending on the pressure, it may be ammonium cation as product.
> 
> For instance, borohydride reduction of Pd nitrate solutions gives Pd metal and ammonia.


So, now we're talking about the potential to form fulminating silver?


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## Lino1406 (Jan 30, 2017)

Silver fulminate contains carbon


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## upcyclist (Jan 30, 2017)

Lino1406 said:


> Silver fulminate contains carbon


We've talked here about silver fulminate (AgCNO) vs. fulminating silver, which basically means "explosive silver compounds." That includes silver fulminate, silver nitride (Ag3N) and silver azide (AgN3). See also the Wikipedia article on Fulminating Silver.


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## Lou (Jan 30, 2017)

I presume you mean silver nitride. And that typically happens in the presence of Group I cations.

And no, if ammonium is produced the silver is metallic and non-participating.

For example...suppose I dissolve silver nitrate in c. aqueous ammonia.
I now have diammine silver (I) nitrate. That is very ill advised to let that evaporate, especially if any sodium or potassium salts are present. 

if, however, I add say, hydrazine to it. I don't get silver hydrazide. I get silver metal and nitrogen gas, quantitatively in seconds.


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## upcyclist (Jan 30, 2017)

Got it. Thanks!


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