# Suppressing NOx with fiberglass



## NobleMetalWorks (Sep 28, 2012)

I came across an interesting result in some material I was recently processing.

I was processing material in a sulfuric cell, filtering with charmin plugs and rinsing the material that was stripped in water, to wash out the Au. After the material was washed clean, I then filtered the wash water to capture the Au. I used fiberglass insulation, I cut a piece that would fit a cullender, that fits into a 5 gallon bucket, I then trimmed the sides so that as the fiberglass became saturated with fluid, it wouldn't be drawn up into the edges of the fiberglass, and then drip outside the bucket. After the first filtering, I then put the pieces I cut in the middle to capture more Au. I filtered from one bucket to another until the wash water was almost clear.

I then removed the fiberglass insulation and put it in a 4,000 ml flask. I stuffed it in with the filtered Au in the center, then folded the sides in so that the bottom of the fiberglass was black with Au, and the top was white. I then made up AR and poured it in. I was expecting fumes, like normal, but nothing happened. The solution turned yellowish then greenish but still no NOx.

What happened is that the fiberglass kept any NOx that was produced, in solution, the NOx is under the fiberglass. This was totally un-expected. It makes sense now that I am thinking about it, the fiberglass was saturated with Au, but the rest was saturated with water. It just very simply kept the NOx under that layer. Here are some pictures.

This was taken about 15 minutes after I added AR. I wish I would have taken pictures before I got this far, if I knew the reaction was going to expose this interesting result, I would have.







In this picture you can actually see bubbles trapped under the fiberglass






Here is a picture closer up. The Au when recovered using a sulfuric cell, is black. You cannot see any black material because there is none, it's all been dissolved. The color you see in the picture is NOx that has been trapped under the layer of fiberglass.






Here is the fiberglass packaging in case anyone wants to know exactly the type of material I was using.






It's been about 3 hours now, I just checked and there is little change in the NOx captured under the fiberglass. I Am going to wait 12 hours and see if it is re-absorbed into the solution. Regardless, this seems to have value. I may attempt to make a small fume scrubber, somehow using this fiberglass to retain the NOx in solution long enough so that it's absorbed by the solution. To that end, I would really love to hear about any suggestions that people may have about building a fume scrubber based on this concept. Matter of fact, I would really like to hear from anyone who might have had a similar experience, I would like to be able to re-create this next time I process using a sulfuric cell.

Any suggestions, corrections, comments, criticism is welcomes.

Thanks

Scott


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## NobleMetalWorks (Sep 28, 2012)

Update, the NOx has still not escaped the solution at all. I put the beaker in a 5 gallon bucket, with a lid, just to make sure any NOx would be trapped in the 5 gallon bucket, and I would be able to tell that some has escaped. I can say with confidence that nothing has yet escaped that I can notice, I am sure small amounts have probably escaped, but I cannot measure or tell.

Scott


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## glorycloud (Sep 28, 2012)

Is it possible that dangerouus fumes are still escaping but just not visible?
What an awful way to end your journey on the planet if possibly
dangerous fumes were escaping but they just didn't look the the
normal red cloud of death? 

I could be way wrong but I just wanted to offer a note of caution.


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## NobleMetalWorks (Sep 28, 2012)

Thanks Glory...

It's possible, even probable, I haven't seen anything myself yet. The rusty brown color you see on the bottom, in the pictures, is shrinking but the brown color isn't making it's way to the top of the solution, so I am guessing it's being re-absorbed. Usually I digest in a round bottom flask, but fiberglass is too difficult to fish out once it's in. I put this reaction in a 5 gallon bucket, under a fume hood, if you notice the pictures are taken in the hood, not easy to tell but the black is the counter, and the white background is the inside of the fume hood.

What interests me is the length of time the NOx has been kept in solution. That was my main concern in making a fume scrubber, was being able to keep the NOx in solution long enough for it to be absorbed by the water. I use little floating balls currently to help keep NOx gas in solution a little longer, along with a spray down stack, bio ball media in the stack, etc etc. But this fiberglass thing is something else totally different.

If you look at the pictures, you can see air bubbles that are trapped under the fiberglass as well. Those bubbles have increased in size some, and have yet to escape. Also it might be worthwhile to note that the Au dissolved came from 18.7 lbs of gold plated pins, so there is a lot of Au.

Scott


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## butcher (Sep 28, 2012)

I cannot think of any simple way to test for nitrogen compounds or the NOx gases,

I do have access to a flue gas analyzer which can determine NOX gases in flue gas (it uses an electronic sensor).

Some nitrogen compounds are not as noticeable as the brown fumes of NO2, but can be dangerous or form NO2 or acids in air or humidity.

Even nitrogen which is mostly what we breath in the air can be dangerous if it displaces the oxygen in the air where you are,from wiki nitrogen:

Rapid release of nitrogen gas into an enclosed space can displace oxygen, and therefore represents an asphyxiation hazard. This may happen with few warning symptoms, since the human carotid body is a relatively slow and a poor low-oxygen (hypoxia) sensing system. An example occurred shortly before the launch of the first Space Shuttle mission in 1981, when two technicians lost consciousness (and one of them died) after they walked into a space located in the Shuttle's Mobile Launcher Platform that was pressurized with pure nitrogen as a precaution against fire. The technicians would have been able to exit the room if they had experienced early symptoms from nitrogen-breathing.


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## NobleMetalWorks (Sep 28, 2012)

Butcher,

Thank you for the information...

I am hoping, since the gas bubbles that have been created under the fiber glass mat are still there, that it means the gas has not escaped yet. I do realize I might be totally wrong in my thinking so I do really appreciate your post.

I am thinking about picking up a NOx detector, anyone have a reliable one for sale? :mrgreen: 

Scott


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## Golddigger Greg (Sep 28, 2012)

Maybe a budgie. Don't name him though...


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