# AR with ammonium chloride is dangerous?



## Mida (Mar 17, 2009)

Hi People...
I have heard that if you dissolve gold with AR made with nitric acid and ammonium chloride,there is the possibility that the salt obtained,when dry, can be explosive.It is possible?.I know that in this case,a fulminate can form when you drop the gold out with alkaline salt,but I'm not sure that it is the unique possibility.
:?: :?: :?:


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## Lou (Mar 17, 2009)

This is a potential concern because the ammonium cation may be oxidized partially to undesirable species. You'd have better luck just using nitric and table salt, which is so cheap there is very little reason not to use it.


Lou


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## Mida (Mar 17, 2009)

Do you have any chemical formula of this process?


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## peter i (Mar 17, 2009)

precipitating a gold solution with ammonia will yield "fulminating gold" (a green high-order (and high-price!) explosive)

http://www.lateralscience.co.uk/gold/index.html


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## Mida (Mar 17, 2009)

I was referring to the product of the process of the oxidation of ammonia contained in the gold ammonium -acid- salt.Usually oxidizing ammonia produces nitrates,but I have no idea how the nitrogen can be combined to produce a powerful micro friction-sensitive explosive.


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## Irons (Mar 17, 2009)

It is a standard procedure in analytical chemistry to destroy the Ammonium Ion using a mixture of HCl and Nitric acid. The Ammonium salts of the PGMs can be converted back to their respective chlorides be heating them in Aqua Regia. The reaction is complete within 10 or 15 minutes and poses little hazard.

It's only hazardous at a higher Ph.


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## Irons (Mar 18, 2009)

When the Ammonium Ions break down in Aqua Regia, the reaction can boil over if heated too quickly. Much like a similar technique mentioned here by others, start with HCl and add only enough Nitric acid, in small increments to complete the reaction.

As Lou mentioned, unless there's a compelling reason not to have Sodium Ions in your solution, you would be better off using Salt.

An even better approach is to follow recommended practice. Once you get good at doing it the right way, it will be easier to understand why the new way didn't work the way you expected it to.


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