# Silver and poormans nitric



## qst42know (Jul 12, 2009)

Poormans nitric works well enough in any other process except for refining silver. What is present or absent that causes difficulties when working with silver?

I know it can be distilled to improve it. But doesn't distilling this both add oxygen and remove impurities?


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## butcher (Jul 12, 2009)

i would think the sulfide would tend to precipitate silver before you want it to, distilling would leave behind the sodium or potassium sulfide in the reaction vessel, the product distilled over should be realitively pure HNO3 and water.


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## Anonymous (Jul 12, 2009)

In the poor mans nitric you still have sulfate ions floating around, they will form silver sulfate which is practically insoluble and coats the silver, slowing or stopping the reaction, also will precip any silver you have until it is used up.

Jim


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## qst42know (Jul 13, 2009)

I'll use this thread to ask. 

Is anyone familiar with the Ostwald process?

In a nut shell ammonia and oxygen are catalyzed to produce nitric acid. The early process was done at normal pressures. Though the modern method is performed under pressure. 

Can this be done at bench top scale using common lab ware? perhaps with an ozone generator?

What apparatus would be required?


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## Platdigger (Jul 13, 2009)

Here is what I found: 

The Oswald Process is the three stage process by which nitric acid is manufactured. Firstly, ammonia is oxidised, at high temperature (900 deg.C.) over a platinum-rhodium catalyst, to form nitrogen monoxide. 
4 NH3 (g) + 5O2 (g) ==> 4 NO (g) + 6H2O	
The nitrogen monoxide cools and reacts with oxygen to produce nitrogen dioxide. 
2 NO (g) + O2 ==> 2 NO2 (g)	
Finally, the nitrogen dioxide reacts with water and oxygen to produce nitric acid. 
NO2 (g) + 2 H2O (l) + O2 ==> 4 HNO3 (l)


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## qst42know (Jul 13, 2009)

Here is an animated cartoon of the process.

http://www.tutorvista.com/content/chemistry/chemistry-ii/nitrogen/catalytic-chamber-animation.php

Do you think a clean ceramic auto cat could be substituted for the platinum wire?


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## Lou (Jul 16, 2009)

It is much more feasible to make sulfuric acid via the contact process rather than nitric acid a la Ostwald.

Check this thread
http://www.sciencemadness.org/talk/viewthread.php?tid=4092#pid46584

and use the search engine!!


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## qst42know (Jul 17, 2009)

Thanks for the link Lou. 

It would seem some folks have performed some interesting experiments along similar lines. 

In your opinion which type of lab glass condenser is best for distilling nitric acid from sulfuric and nitrate?


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## Lou (Jul 18, 2009)

A 600mm Liebig will work fine. 

There are fancier coil type condensers, but they have more holdup in the condenser.


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