Aqua Regia

[SeniorSchmu]

Hi

 

I have a question and anybody's help would be welcomed. I tried making aqua regia to dissolve gold nanoparticles. I tried 4:1, 3:1 and 2:1 of HCl:HNO3 concentration ratio (in volume). Everywhere I read about aqua regia, it is said that it will produce some fumes but I didn't get any. Could it be because my acids are not concentrated enough? Both have a concentration of 50%. Will it dissolve my nanoparticles anyway?

 

Thank you

[JGK]

I suspect you will need the strongest acids you can get, HNO3 is available at >90% and HCl at >37%

[Arthur Dent]

I suspect you will need the strongest acids you can get, HNO3 is available at >90% and HCl at >37%

 

Indeed, the acids have to be concentrated. But I believe that "technical grade" Nitric Acid 42 BÉ (67%) is enough. The HCl can be 20 BÉ (32%)

 

The ratio is approximately 1 part HNO3 for 3 parts HCl. I tried it and it works. The yellowish fumes are not that intense, but are still extremely toxic and pungent. One whiff and it'll have you choking and tearing up. Do this mixture outside and up wind (ideally in a ventilated laboratory fume hood, but not everyone has one of those ).

 

It is a monstrous acid... it will eat up any metal, so your precious metals will be dissolved with whatever metal (copper, iron) is also included. Be very careful and work with goggles and gloves, even a tiny drop on your skin or in an eye will result in a world of hurt!

 

- Robert