# Any ideas for a sponge/filter that resists AR?



## NobleMetalWorks (Jul 30, 2012)

I'm adapting my understanding and use of salt water aquarium filtration design to the AP process. This is what I have done thus far.

I was given a 110 gallon acrylic tank by a friend that no longer keeps tanks. The acrylic has been fused together using a chemical method so that the tank is really one piece. I have had the same type of plexi submersed in one of my AP tanks for over 2 months now without any degradation, crazing, cracking or other damage, and from what I have read it doesn't seem I should have any problems with the etching solution affecting the plexi.

I bought a little giant acid rated pump, to move the solution.

I have a 30 gallon sump/reef filter that is basically another acrylic tank partitioned so as to filter with different media. 

I have a pre-filter that fits on the back of the tank, and hangs over on the inside.

This is how it works. The pump, pumps solution into the tank, and agitates the solution so I don't need any mechanical agitation. The solution spills over to the gravity pre-filter that hangs on the back, and then falls down PVC pipe into the 30 gallon sump underneath to be pumped back into the tank. As the solution is pumped back into the tank it's split into four outlets that agitate in different directions and at different levels.

When the gold foil comes loose, it eventually is picked up by the pre-filter, and then moves down the PVC pipe into the sump filter.

The only part I am missing is a sponge filter that is resistant to HCl/Cl or even AR. The idea is to put this sponge filter in the sump where the PVC drops the solution with the gold foils. The sponge filter would capture all the gold foil, then all you would have to do is remove the sponge filter, immerse it in HCl/Cl or AR to dissolve the gold into solution and out of the sponge.

I have a few ideas later for a eletrowinnowing setup using carbon as the collector to be immersed in AR to collect the Au from the carbon, but that's a little further down the road. 

Does anyone know of a sponge material that would be resistant to Ar? This type of material might also be useful as a charmin plug (thanks Geo).

Scott


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## rshartjr (Jul 30, 2012)

Fiberglass matte, maybe? Boat hull repair patches use either thin, tightly-woven patches or a thick matte of randomly-laid spun glass fibers. Most folks use glass vessels and stirring rods for the process, anyway. It could be just what you're looking for.

Scott


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## NobleMetalWorks (Jul 30, 2012)

rshartjr said:


> Fiberglass matte, maybe? Boat hull repair patches use either thin, tightly-woven patches or a thick matte of randomly-laid spun glass fibers. Most folks use glass vessels and stirring rods for the process, anyway. Could be just what you're looking for.
> 
> Scott



That's a good idea, you can make charmin plugs out of it as well.

I might also try miners mat, but I think that is made out of some type of vinyl, so I'm not sure how well it will stand up.

Another material I ran across is PVA sponge. Only problem is that I think it's too dense, and wouldn't allow water flow through it readily enough to use in a high rate of flow filtering system.

Miners Mat seems like the perfect designed material, anyone know if there is any miner mat material made out of PTFE or some other form of Teflon, or Poly?

Thanks

Scott


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## Lou (Jul 30, 2012)

We use Kavon filter products polypropylene 1-3 cfm (essentially 1 um) PPF 18 and PPF15 for ammonium hexachloroplatinate and the like. Also works well for Pt sponge but leaves 2 g Pt hold up/filtration per 3.14 sq ft and eventually quits filtering and then has to be thrown in the reactor and they come out white again.



Tell him Lou sent you and you want the same thing as me and Cabot. Just make sure you specify that you don't want 36" or 24" (or maybe you do!). 

www.kavonfilter.com


I recommend everyone here, their products are great.


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## NobleMetalWorks (Jul 30, 2012)

Lou said:


> We use Kavon filter products polypropylene 1-3 cfm (essentially 1 um) PPF 18 and PPF15 for ammonium hexachloroplatinate and the like. Also works well for Pt sponge but leaves 2 g Pt hold up/filtration per 3.14 sq ft and eventually quits filtering and then has to be thrown in the reactor and they come out white again.
> 
> 
> 
> ...



Lou,

You know what my next piece of equipment is going to be? A hotline, I'm going to install a hotline on your end, and mine, hahaha. You have the answers I am looking for lately. It's really kind of amazing.

Thanks once again Lou,

Scott


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## Lou (Jul 30, 2012)

No problem. I do this for a living.

Rh refine batch calling...out. 


As for the polypropylene, they're a game changer and I've been using the twill for the past six years. Steve of all people introduced me to the felt, God bless his soul.



Lou


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## NobleMetalWorks (Jul 30, 2012)

I have a feeling this is going to do the job perfectly.

Scott


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## Oz (Aug 2, 2012)

Scott,

If all you are doing is wanting to catch gold foils like in an aquarium filtration set up, why not just use fiberglass insulation like used to insulate walls and attic in a home. You can get it local for next to nothing, and you can digest your gold out of it and then reuse it.


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## NobleMetalWorks (Aug 2, 2012)

Oz said:


> Scott,
> 
> If all you are doing is wanting to catch gold foils like in an aquarium filtration set up, why not just use fiberglass insulation like used to insulate walls and attic in a home. You can get it local for next to nothing, and you can digest your gold out of it and then reuse it.



Oz, that's a good suggestion, and I have been using it, however some of the foil is in such small particles that the fiberglass is unable to filter it, it moves right through it. Or, if you don't pull the fiberglass and clean it often, the movement of the fluid through it breaks it up. This is continual filtration, not a one time filtration. For example, when you use fiberglass as a charmin plug, you are only filtering through the fiberglass that one time. In the setup I am talking about, whatever is caught in the filter has to also be able to survive constant filtration without breaking up to the point where filtering it would require a material so dense, that you wouldn't be able to filter fast enough.

So the fiber has to be large enough to allow for a high flow rate, yet dense enough to capture and retain small particles without breaking into smaller ones.

Later, when I have the time and space to play with the idea, I would like to also adapt eletro-winnowing somewhere in line with the filtered solution, like a block of activated carbon perhaps that was able to collect gold as it's filtered.

There is so much that I can adapt from my salt water tanks, to the processes we use that I am certain I can come up with some efficient combinations. The nice thing is that I am not trying to re-invent anything, just adapting inexpensive off the shelf technologies.

In the filter setup I am planning on using 2 types of filters and possibly three, but the two I have settled on are the course fiberglass, and the finer poly felt. I think this will allow for the right flow rate, and retain the most Au foil without breaking it up.

Scott


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## Palladium (Aug 2, 2012)

This is what i use. I use these in a 15 Gallon Drum. You can even got heads to fit the sock. I like the way you think Scott. Kind of reminds me of some of things i did when i got started. I've designed several experimental systems. If you weed through my post you will find reference to some ideas that might spark your interest.

http://www.dudadiesel.com/choose_item.php?id=POGP1S

http://www.ebay.com/itm/1-Micron-Glazed-Polypropylene-7-x-16-Filter-Bag-Felt-Size-1-Sock-Biodiesel-WVO-/350531356909?pt=LH_DefaultDomain_0&hash=item519d4c08ed


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