# Processing silver from print shop?



## feffer777 (Jan 4, 2018)

I retired from the printing industry years ago, but have maybe 8-10 pounds of material from a shop centrifuge device that processes fixer. We used to sell it and used litho film to a guy who processed or resold it. The device spun and used an electrolytic process to extract the silver. I don't know the chemical form...maybe silver oxide? 

Is it worthwhile trying to extract the silver? Since litho film is not used much (or at all) anymore, I don't think I can sell it as is? Can someone point me to the way to handle this? Since this is a one time thing and not a hobby, I know there will be an upfront cost for required materials and also a time cost. I apologize in advance for not researching this site before posting. Past experience tells me, I'll waste a lot of time poking around and may get it wrong anyway. thx!


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## FrugalRefiner (Jan 4, 2018)

Since it's a one time thing, my advice would be to have one of the members here toll refine it for you. You'd have to spend a lot of time studying to even be able to figure out what you have, let alone how to process it. Sourcing the necessary chemicals, then dealing with the toxic waste just isn't worth it for a one time thing. There are members here who can process it for you for a percentage of the silver. I'm sure one or two will come along and contact you shortly.

Dave


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## Palladium (Jan 4, 2018)

Is it black and stinks?
Probably sulfide.

Chris may be able to run it for you! https://goldrefiningforum.com/phpBB3/memberlist.php?mode=viewprofile&u=49140


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## goldsilverpro (Jan 5, 2018)

I may be wrong, but it sounds like the rotating part of the equipment is not a centrifuge, but is the rotating stainless drum cathode in an electrolytic tank. In a fair sized tank, these stainless steel drums are about 6" in diameter and are made of heavy sheet metal. The silver deposits on the outside of the drum. If the conditions are perfect, the silver will deposit as a white, hard, brittle, silver metal, which can be 98% pure and is removed by tapping it into pieces with a hammer. At the other end of the spectrum, when the conditions are lousy, the deposit can be black, soupy, stinky, and only about 60-70% pure, when dried. In both cases, the other 2% or 30-40% of the weight is silver sulfide, as Ralph noted. Usually, the silver percentage is somewhere between these 2 extremes. 

The black soupy material is fairly non-homogeneous and it might be hard to get a good sample for assaying, especially if there are chunks of silver metal in it. If you do sample it, you should first dry it with fairly low heat, then grind it up and blend it. Of course, weigh it dry.

As I've written at least 20 times, the silver can be simply purified by melting in a gas crucible furnace, with a bunch of borax, and with several lengths of rebar that are long enough to stick up out of the crucible, so they can be easily removed before pouring. The iron combines with the sulfur in the silver sulfide, releasing the silver. The iron sulfide goes into the slag. The melt is then poured into a mold and, when cool, the slag in broken away from the silver bar. Some people dump the mold when all is solidified (but still quite hot) and then quench the hot bar in water, This makes the slag separate better. 

If done right and all the slag is removed, the silver bar will be at least 999 pure and maybe 9999. The silver on the film is quite pure and will remain pure unless you contaminate it with something like using a crucible that has been used to melt copper. The iron won't contaminate the silver because silver and iron won't alloy under these conditions.


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## feffer777 (Jan 12, 2018)

goldsilverpro said:


> I may be wrong, but it sounds like the rotating part of the equipment is not a centrifuge, but is the rotating stainless drum cathode in an electrolytic tank. In a fair sized tank, these stainless steel drums are about 6" in diameter and are made of heavy sheet metal. The silver deposits on the outside of the drum.


 This is correct. In the past, I've seen light grey material deposited on the drum. This batch was pulled off long ago, but if memory serves, the surface was grey but some blackish material under it. Nothing "soupy" So this probably has purity about 70% or above. From my perspective, the good news is that this can be processed w/o chemicals, and the procedure is fairly simple.

My question would be, is this something I can do myself? Or is that unpractical and it would be better to find someone (perhaps from this forum) to do it. I could probably buy a crucible, tongs, borax, rebar and mold (and I have a propane torch). But I don't think I could buy a gas crucible furnace for a one-time project. Can they be rented? Or would the blow-torch work?


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## Elektrikis (Mar 6, 2018)

feffer777 said:


> I retired from the printing industry years ago, but have maybe 8-10 pounds of material from a shop centrifuge device that processes fixer. We used to sell it and used litho film to a guy who processed or resold it. The device spun and used an electrolytic process to extract the silver. I don't know the chemical form...maybe silver oxide?
> 
> Is it worthwhile trying to extract the silver? Since litho film is not used much (or at all) anymore, I don't think I can sell it as is? Can someone point me to the way to handle this? Since this is a one time thing and not a hobby, I know there will be an upfront cost for required materials and also a time cost. I apologize in advance for not researching this site before posting. Past experience tells me, I'll waste a lot of time poking around and may get it wrong anyway. thx!



https://www.youtube.com/watch?v=QCvi8TC5i88
https://www.youtube.com/watch?v=g8Pw7uiZS-g
My metod for fixers.


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## rickbb (Mar 6, 2018)

feffer777 said:


> This is correct. In the past, I've seen light grey material deposited on the drum. This batch was pulled off long ago, but if memory serves, the surface was grey but some blackish material under it. Nothing "soupy" So this probably has purity about 70% or above. From my perspective, the good news is that this can be processed w/o chemicals, and the procedure is fairly simple.
> 
> My question would be, is this something I can do myself? Or is that unpractical and it would be better to find someone (perhaps from this forum) to do it. I could probably buy a crucible, tongs, borax, rebar and mold (and I have a propane torch). But I don't think I could buy a gas crucible furnace for a one-time project. Can they be rented? Or would the blow-torch work?



I used to be in the printing biz as well, in the prep dept. that produced all that silver and litho film. That grey material is more like 98% pure, (or higher), the black on the bottom is where it was in contact the cathode and will have a small amount of sulfide due to over amperage after the silver built up thickly on top of that first layer. 

If this were in my hands I would get a medium to large melting dish, (or 2 or 3, hint, hint), a mapp gas torch like plumbers use, coat the melting dish with a pinch of borax and start melting silver and pouring bars. You could use propane but mapp gas burns a bit hotter. I doubt you will need to refine it at all.

Edit to add;

Look down in the sell and trade section, a member there will take your electrolytic flake as is and trade back to you in .999 minted coins or bars. An assay fee and a bit for his profit and you will have pounds of .999 silver on your hands. And you don't have to do anything other than ship it.


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