Aqua Regia Disposal...

Kevin Crabb kcrabb at
Mon Oct 29 16:09:03 PDT 2007

Hello SNF Safety Folks,

I am hoping to use aqua regia (mixture of 3:1 concentrated hydrochloric acid
to concentrated nitric acid) to remove platinum and gold grid structures
from my wafer.  I was told it is okay to do this at the wetbench general, as
long as I collect my waste separately.  

However, after doing more research, it has come to my attention that aqua
regia will fume (it produces chlorine gas) for hours/days (depending on the
temperature, volume), and I was wondering how best to deal with this.  Would
it be possible to leave the waste container open in the fume hood until it
finishes fuming?  If not, is there a vented bottle cap that could be used?
Any information/suggestions on how to handle this situation would be greatly
appreciated.  Thanks,


kcrabb at

PS-If it matters, I expect to only need ~200mL of the aqua regia mixture.

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