Gun Cotton or Not That is the Qustion...

[awbrew]

So after Using HCL/CL and droping with zinc. I always use fine filter circles to recover pgms. I scrape the pgms off the filter. The dirty filter circles that are left, I have been soaking in a little HCL/Nitric and rinseing to clear and then throwing it back in the paper sweeps with the paper towels I have used to clean up any PGM spills. ( don't worry I'm going out right now and moveing my trash can far away from the garage where I have set up shop... I was watching the home scientist and seen his gun cotton (nitrocellulose) vid, he says that a scientist discovered it accidently when he spilled nitric on a towel and hung it next to a fire to dry. The towel went up in smoke!! I got to thinking that their might be some other folks out there making the same mistake. I haven't tried to light the filters yet. I know thier is a lot of glass in them and it may not apply, but I believe this thread may help some one.

Can anyone shed a little light on this thread ? As you know You guys are the Teachers, I am just the Student...

 

[Palladium]

Sure can. I just had a learning experience just the other day like that. I had a blowout on some gold filled i was removing the base metals from. Just nitric and water with the undissolved foils boiled over my vessel and catch basin and wound up on my cardboard catch basin. I let it soak in and moved everything till it did. Once it soaked in all i had was the foils on the surface so i folded the card board up to keep the foils from coming off until it was incinerated. I have a big old stainless steel plate laying out back so i though i would lay the nearly dried nitric soaked cardboard on it to finish drying so i could incinerate it. I went about my business for an hour or two and all the sudden smelled smoke. I went over to the cardboard and it was smoldering like burnt toilet paper. The steel plate had gotten hot enough to combust the nitric acid in the cardboard. I covered it up so air wouldn't disturb it till it finished so it wouldn't get blown away and when it was done i cleaned it up with a brush.

 

[awbrew]

Nice Post Palladium... I'm so glad I seen the Home Scientist Video on this, because I was throwing these back in the paper sweeps. It would have been bad if the conditions for ignition had been met... The paper sweeps was setting in my shop. Ouch!

 

[bogarasjoe]

Once when I have removed legs from ceramic CPU with a torch, the hot ceramic cpu falled accidentaly to a filter paper, and burned it so fast. And it burned so fast, it could be because I think I filtered nitric on it.

 

[bogarasjoe]

Cellulose nitrate is made from the mixture of sulphuric acid and nitric acid at low temperature and without neutralizing the acids very well, it could be instable. And it could form some nitrate without sulphuric too, sulphuric is used because of dehydrating.

 

[NobleMetalWorks]

Actually, nitrocellulose can be created from almost any nitrating substance. It's specially dangerous when it's wood, and not filter paper or cloth towels. Some people who make wood enclosures, and do not coat them with some acid resistant material like fiberglass. The wood will soak up Nitric Acid fumes as well as NOx which both will create nitrocellulose. If you cover your beaker you are digesting metal in AR, with a paper or cloth, it will soak up these gases and might create nitrocellulose.

I Keep a container I put all my filters into after use, I have a plastic lid that fits snug on the top but will pop off if gases start to build up. In this way I limit the amount of oxygen that the filters are exposed to and reduce the chances that the filters will ignite. I burn my filters as soon as they are dry so that I don't accumulate too much of this type of material.

Scott

 

[awbrew]

The subject of this thread, May very well save someones Garage, or house. Its hard to believe how something so simple, Can become become a problem that quick. I remember when readng on how to build your own Hood, they warned about using wood, but if you did to be sure and seal the wood with Acid resistant epoxy. Thanks SBrown for the input...

 

[Palladium]

Just for info: I just finished the cardboard from the spill over, about 15 grams, that's a lot of money! Valuable lesson for me i learned here. Not only the possible monetary loss, but just the experience of once again having to clean up a mess i myself created and understanding what i need to do to not let it happen again was invaluable. Lot of extra work that shouldn't have been.

 

[BangBang]

Wow, That's a great heads-up. I too have old filters that I keep in a box outside my house. As soon as they are dry I'll burn them and just keep the ash.

This thread reminds me of another story that exemplifies just how unstable gun cotton is.
Many years ago my father (as a young man) used to play in the swamps of NJ.
(Where the Meadowlands sports complex is now, home of our beloved Giants)

Anyway the locals knew that if one dug just a few inches below the surface of the bogs, one would find a layer of soggy orange gun cotton.
The result of military dumping I was told.
If removed and allowed to dry it was quite flammable- So much so that my father lost most of the skin on his arm while simply reaching into a box of dried gun cotton to pull out its contents. I suspect a static discharge set the box ablaze.

So for what it's worth - Consider grounding yourself whenever handling anything that may behave like gun cotton.

 

[awbrew]

Just for info: I just finished the cardboard from the spill over, about 15 grams, that's a lot of money! Valuable lesson for me i learned here. Not only the possible monetary loss, but just the experience of once again having to clean up a mess i myself created and understanding what i need to do to not let it happen again was invaluable. Lot of extra work that shouldn't have been.

Ouch! thats over a half of an oz. But at least your shops ok and You still have the tools to start over and do it again... And you sound a lot like me, by fileing that bit in the education file. My education file has grown and become a lot more like a Education File Cabinet over the years... LOL

 

[awbrew]

Wow, That's a great heads-up. I too have old filters that I keep in a box outside my house. As soon as they are dry I'll burn them and just keep the ash.

This thread reminds me of another story that exemplifies just how unstable gun cotton is.
Many years ago my father (as a young man) used to play in the swamps of NJ.
(Where the Meadowlands sports complex is now, home of our beloved Giants)

Anyway the locals knew that if one dug just a few inches below the surface of the bogs, one would find a layer of soggy orange gun cotton.
The result of military dumping I was told.
If removed and allowed to dry it was quite flammable- So much so that my father lost most of the skin on his arm while simply reaching into a box of dried gun cotton to pull out its contents. I suspect a static discharge set the box ablaze.

So for what it's worth - Consider grounding yourself whenever handling anything that may behave like gun cotton.

Bangbang, thats unreal... but good to know... Do you think that some thing natural, like a volcano or something could have created that condition...?

 

[Palladium]

I learn new things all the time. The boil over happened not from the lack of knowledge on my part, but from the lack of experience. I have been running bigger and bigger lots and just made a rookie mistake by not taking into account that when things go wrong on a small scale it's a small problem. When things go wrong on a larger scale .... well you get the idea. It's that curve thing and getting graded on a sliding scale don't work the same in gold refining as it does in academics. :mrgreen:

 

[awbrew]

It's that curve thing and getting graded on a sliding scale don't work the same in gold refining as it does in academics. :mrgreen:

I Hear you...haha