Ammonium nitrate and silver

[Platdigger]

When disolving silver in nitric made from sulfuric and ammonium nitrate.

If the silver is cemented to copper, is there any danger of forming explosive
ammonia/silver compounds?
Randy

 

[Oz]

I would think there is the risk. It is an especially good question however because I would think that the ammonia would come over with the nitric if distilling the nitric as is typically done to remove sodium and chloride salts.

Cementing on copper may or may not mitigate the risk if present as you would already have ammonia and silver in solution prior.

Perhaps if you had distilled your nitric from ammonium nitrate, a secondary boil in an open griffin beaker would evaporate off the ammonia, but I am not sure if an azeotrope is formed between the two or not.

 

[Platdigger]

I am talking about using sulfuric acid and ammonium nitrate "staight up" so to speak.
Without distilling.

 

[Oz]

Silver nitrate and ammonia is not suggested for the reason you were asking. If you are dissolving your ammonium nitrate then you not only have your nitrate in solution but also your ammonia.

For that reason I would think it should be avoided unless you first remove the ammonia from your nitric before adding silver. How great the risk is if you are immediately cementing on copper I will leave to the chemists here to answer.

Personally I see no good reason to try that potential hazardous combination without being assured the ammonia was removed. Then again you may have an unlimited source of free ammonium nitrate and it might be worth the distilation i think may be required to make it safe.

 

[nicknitro]

Oz,

Could he use HCL to convert the Ammonium Nitrate to say Ammonium Chloride or something similar and create safer sodium nitrate?
Or too hard a process? I was just wondering. I think it would be easier just to buy some NaNO3 but, if he has NH4No3 how hard is it to make a safer nitrate?

Thanks,
Nick

 

[Oz]

Nick,

You have asked me questions that I am not qualified to answer. I myself would like to hear from the chemists on the forum about the removal of the ammonia from the nitric process Platdigger was proposing. Ammonia evaporates off easily however I am unsure if the ammonia forms an azeotrope such as ethanol/H2O that will not allow its complete removal by simple evaporation.

I am also unaware of a good test to be sure of an endpoint for evaporation. First thought was Cu, however in nitric it would give the same color indicator.

 

[Lou]

Ammonium nitrate will not react with silver metal to form anything dangerous, if acidic conditions are maintained (this means that you're ammonium nitrate + sulfuric acid is really acting like nitric acid contaminated with ammonium sulfate).

Ammonium and ammonia are two different animals. If base is added, then ammonia may be formed and react with the already precipitated silver oxide, and that could lead to a bad situation. As long as it is in acid milieu, you ought to be fine.

 

[Oz]

Lou,

Thank you for clarifying that! I am still curious as to how effective evaporation would be for the removal of “ammonium”, or would it stay behind as ammonium sulfate allowing you to distill off clean nitric as is done with other poor mans nitric recipes?

 

[Lou]

It would probably be left as an ammonium sulfate cake. If there is air present in the system and in excess, it is conceivable to oxidize the ammonium to nitrate to nitrogen oxides which will be in your nitric acid.

Ammonium is not a stable cation, in strongly acidic oxidizing solutions, it will become nitrate; in strongly basic solutions, it will become ammonia.

 

[Oz]

Thank you Lou

 

[Platdigger]

Yes, Thank You, this is good stuff.....