# filter material?



## gbaldwin75 (Jan 9, 2008)

what kind of material would i use in the in line filter for my fume hood?


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## goldsilverpro (Jan 9, 2008)

Harold?


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## Noxx (Jan 9, 2008)

Does activated charcoal can be used ?
I know it cuts the odours but what about NOx gases ?


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## Harold_V (Jan 9, 2008)

My purpose in filtering was strictly to recover values, not to control other emissions. For that purpose, I used fiber glass furnace filters, which incinerated well, and became a vital part of the chemistry for the succeeding melting process (I added silica to my flux, so the filters became part of the added silica). 

I had long considered doing something with the fumes, but I sold the business before taking any action. Sorry----I don't have much to add. 

Harold


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## goldsilverpro (Jan 9, 2008)

Shor once sold a self-contained AR refining machine that used separate limestone and charcoal fume filters to kill the acid and the NOx, respectively. However, someone once told me that charcoal/NOx reactions can start fires.


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## Lou (Jan 9, 2008)

Charcoal is good for organic solvent vapors, not for much else.

A PVC pipe packed with lime would probably be one of the best for this acid vapor neutralization. 

Most fume hoods in commercial labs don't even bother, they just exhaust :-/

There are threads on http://sciencemadness.org/talk that have info on building fume hoods/cupboards which implement both charcoal and Ca(OH)2.


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## Irons (Jan 15, 2008)

What they call play sand is coarsely ground Marble (Calcium Carbonate) Its only a couple of bucks a bag. It's coarse enough to use as a filter. 

I took a piece of fiberglass window screen, put in a pound or so and keep it in the inlet funnel of my stockpot. It neutralizes any acid fumes that leak out. It's also handy to kill any spills.


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