distorto - 27-7-2011 at 20:13
In my laboratory we always dissolve gold with aqua regia. (3:1 conc.HCl + conc.HNO3) And we've found that our fume hood is going to broken.
I seems that the reaction produce red-brown gas (I think it's N2O2) that destroy rubber, metal and pump. I also believe that there are many oxidizing
transparent gas coming out too.
The question is what should I do to protect the fume hood? Is water trap going to work? And how to apply the water trap.
Thanks.
hkparker - 27-7-2011 at 20:53
Yes, aqua regia decomposes to release NO2, NOCl, and Cl2, all of which are very nasty. Work in a fume hood or do the reaction in a container where
you can lead the gasses under water. Be sure to use a suck back trap.
Paddywhacker - 27-7-2011 at 23:37
The usual way that I have dealt with acid fumes is to expose concentrated ammonia solution. The ammonia fumes will neutralise the acid fumes. But
you will get visible smoke, and that might alarm some people even though the smoke is much less harmless than the invisible acid fumes.
blogfast25 - 28-7-2011 at 05:59
Isn't urea the recommended scrubber solution? I do all these nitric based dissolutions in open air when there's a bit of wind available...
hkparker - 28-7-2011 at 10:31
I use urea crystals for NO2 and it is by far the best. Come to think of it I know it absorbs chlorine as well, but I'm not sure about NOCl.