AR Fume Safety/Prevention/Treatment

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I have been working outside to avoid the fumes generated and I've been doing my best to capture the fumes in glass apple cider jugs in order to recycle the fumes back into nitric acid while reducing the environmental impact as much as possible. It is unfortunate in my opinion that NOx fumes are dangerous because the sweet smell and taste of this gas makes the fumes almost pleasant to be around in extremely small quantities. This sweet smell makes NOx fumes all that much more dangerous because the senses that provide warnings about dangers in the air are registering very little to no danger when in fact you're being slowly ,or in some cases rapidly, poisoned. It's this lack of warning that makes these fumes so dangerous especially to those who haven't read or don't pay attention to the warnings
written all over the internet.
 
I too work outside when dealing with any chemical products. The little scents off of AR I catch smell exactly like the exhaust from my 2009 diesel standard firetrucks. Both are bad for you, and I avoid breathing them both as much as possible.
 
solar seeker said:
It is unfortunate in my opinion that NOx fumes are dangerous because the sweet smell and taste of this gas makes the fumes almost pleasant to be around in extremely small quantities. This sweet smell makes NOx fumes all that much more dangerous because the senses that provide warnings about dangers in the air are registering very little to no danger when in fact you're being slowly ,or in some cases rapidly, poisoned.
Click to expand...

It IS crazy that such a poisonous gas smells nice. AR is at least very pungent and burns your nose. And clorox + HCL... forget about it!
 
goldenchild said:
It IS crazy that such a poisonous gas smells nice. AR is at least very pungent and burns your nose. And clorox + HCL... forget about it!
Click to expand...

If you are working outside put a hose hold box fan blowing the fumes away from you.
 
I picked a old small refriderator off the side of the road. Put it on its back, put a few inches of water,my 5 gal bucket, with a few rams and pins. pured on the real AR when the red fumes started closed the box for 24 hours. no fumes, no pins just some green liquid a blank ram sticks. works for me. Is there a bad side to this the book said the water absorbes the fumes? the system was drained because i scraped the compressor for the copper (brown gold to me) ;)
 
The NO2 fume’s would need bubbled through the water for the water to absorb them which would make dilute nitric acid in solution, NO fumes would have to be mixed with oxygen to form NO2 gas before the water would absorb it, the surface of the water may dissolve some of these fumes very slowly, but I would not think the water could absorb much of them, I suppose that the refrigerator could have formed dripping condensation that these gases that could mixed with, or the gases may not have gone into solution much at all, and just changed forms from the red brown gas that normally evolves in the reaction, one way to tell is try measuring the pH or specific gravity of the water. Another possibility maybe if there were exposed metals the fumes may have just made salts of the exposed metals until fumes were consumed.
 
WARNING: No "cartridge type" respirator will filter out nitric fumes, NONE!!!

"Activated Carbon will capture a significant amount of the noxious fumes"
And it is the missing ingredient for a out of control fire when working with NOx gases.


BFRC= http://tinyurl.com/nlrsu8t
No that wasn't mine BFRC, LOL!!!

A leak in a nitric acid plant in Geleen, there has escaped a large amount of nitrogen dioxide on April 9, 2010. The red / brown cloud is nitrogen dioxide.

Search and learn before you die !!!
Stay safe and take care.
 
Has anyone tried adding conc. H2O2 to aqua regia before? I am trying to better dissolve tungsten and I have seen in a few spots that the addition of H2O2 to aqua regia can help with this but I am worried about whether or not this process is dangerous? I am not too keen on adding an oxidant to a superacid. If anyone has tried this I would really appreciate concentrations used and a description of how the reaction went. Thank you!
 
Hi PalladiumPrincess, Welcome to the forum.
First, the thread you are referring to originated from 2007. Since then some new insights, best practices and preventive control measures may have become the consensus.

We tend to avoid creating BFRC, because a BFRC means a lot of nitric goes up in 'smoke' and is thus wasted. to achieve this: don't add large amounts of HNO3 to the solution, and never pre-mix AR, unless you know it will all be consumed and leave some metal untouched.
next: use scrubber flasks with a dry trap in between to catch harmful fumes before they are released to the environment. (and your lungs) forget cartridge respirators. Prevention and containment is key.

Have you read the first page of this thread? Post 11 from goldsilverpro mentions this excact H2O2 addition and how it works.
It basically supplies an abundance of oxygen to the AR, regenerating the NO in to NO2, which can be absorbed by the solution, reusing the nitric.
How were you planning on creating said BFRC? what kind of 'ore' material? how much? which process will be used?
Ask here on GRF before creating a big problem you can't get out of anymore.
Have a plan before you start!! Stay healthy and alive!

Martijn.
 
Thank you for your reply Martjin!
If you do not mind me asking, what does BFRC stand for? (I am new to many of the acronyms used).
I have access to a chemical hood and I am planning to use about 15 mL of AR to dissolve about 0.5 grams of material in a beaker ( do not have scrubber flasks). I was going to try adding about 5 mL total of 30% H2O2 (dropwise) to the solution in order to better dissolve the tungsten in the material. But I want to be sure before I do this that it is safe to do so.
I did see the post about how the reaction works but I am having trouble finding information on how dangerous H2O2+AR is? For example, is 20 mL in a fume hood considered dangerous?
Will there be a large amount of heat generation and/or fumes?
And I am wondering how long the solution remains active and what the proper disposal of such a solution is if anyone knows this?
I appreciate any guidance at all! Thank you ☺️
 
PalladiumPrincess said:
Thank you for your reply Martjin!
If you do not mind me asking, what does BFRC stand for? (I am new to many of the acronyms used).
Click to expand...

See A Glossary of Common Terms for acronyms and terms you don't know.

In this case it's the Big Freakin Red Cloud of NO2 fumes that evolve from nitric acid reactions.
 
Thank you FrugalRefiner for the clarification. I am wondering though if adding H2O2 to AR will form BFRC? According to the post by goldsilverpro (» June 22nd, 2007, 12:50 am) on the first page of this forum the H2O2 works to reduce the fumes. I am wondering if anyone here has experience with this particular solution? I am a little apprehensive since there is very little published literature on the topic. (In particular safety).

Thank you again and I appreciate any guidance on the topic!
 
I have no experience with adding H2O2 to reduce NO2 fumes.I try to avoid it by taking it slow with additions of HNO3.
But adding H2O2 should be done slowly because it can cause some heat and reaction i have understood it well.
Start small and get experience with small amounts in large beakers with room to spare.
Martijn.
 
Here is a video by metalicmario, known on the forum as goldenchild. I posted the link to the YouTube page since there is a few comments worth looking into.


https://www.youtube.com/watch?v=8PhE7GIUrxA
 
I just read this entire thread.
I’ve dissolved some silver in 50/50, nitric acid/distilled water. Outside.
Hoping to get some karat gold going in aqua Regia.
My question is, what happens to these fumes, do they drop, or rise and go where?

Again, I’m outside.
 
Hartbar said:
My question is, what happens to these fumes, do they drop, or rise and go where?
Click to expand...

Watch someone smoking a cigarette. The smoke they breathe out is at first visible, because it is concentrated. But then it kind of disappears... But it's only being diluted. All of the smoke particles are still there, but as they become more diluted as they spread, they're no longer readily visible. It's the same with your fumes. They're still there until they react with something. Ideally it will be in your fume scrubber. In the worst case it will be in your lungs. :( Whether they rise or drop depends on the fumes you produce, but they should all be treated.

Dave
 
The fumes I produce so far are:
From 50% nitric acid 50% distilled water, being used to dissolve sterling silver.
I’m about to try AR, nitric and hydrochloric on karat gold and gold filled.
I understand everyone’s mention of fume hood and scrubber. At this point I don’t have facilities for one.
However, I am doing this outside, with two large fans blowing fumes away and hopefully up.
 

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