# The original silver trap windows series



## Rokunited (Oct 23, 2012)

Hi. I've got my hands on a fixer filter called the original silver trap windows series. My question is how would one go about recovering silver from the filtering device. I've read these can hold up to 60 Troy ounces. This thing also looks like it has massive build up in it. Tons of visible particles. How would I go about recovering the silver from it? Any thoughts or experts who can chime in?


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## goldsilverpro (Oct 23, 2012)

Here's what it says about this product in the company's literature. The underlining is mine.



> The amazing Silver Trap Window ST-WD and ST-WDC
> (compact) metallic replacement cartridge system is the
> only metallic replacement system you will ever need for
> silver recovery from Medical Imaging/B&W Fixer.
> ...



It's basically packed with a roll of iron screen (sometimes copper plated), instead of the more common steel wool packing. As it says, the iron is sacrificial. In other words, as the silver cements onto the iron, the iron dissolves. Therefore, the more iron remaining, the less silver is in there. If all the iron is gone, you could have up to 60 oz of silver. In practice, though, I doubt if 60 oz has ever been recovered from one of these. The maximum capacity is probably just a mathematical calculation based on the weight of iron used. How much iron is left? Can you get an approximate weight?

I've processed a lot of these but never chemically, since that would be quite difficult and would be a mess. There are 3 things to deal with: (1) the remaining iron (2) the visible silver, which is usually a gray color (3) the black sludge probably present, which contains silver sulfide. Not an easy combination and the more iron you have, the more difficult it would be. 

The standard way (in general) is to first remove any plastic, dry the cores and sludge, and then melt the cores and sludge in a gas-fired crucible furnace fluxing with borax/soda ash, and using a few lengths of rebar to react with any sulfur present in the black silver bearing sludge. If there is a lot of iron, the rebar is probably not needed. Also, a lot of iron will require a lot of flux. And, the more flux, the more silver will be trapped in it, usually as BBs.

I don't want to discourage you, but these are one of the most difficult-to-refine items on the planet, unless you have the right melting equipment and know what you're doing. With some exceptions, about the only refiners doing it are those that specialize in it and do it in large volume, probably in reverberatory furnaces.


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## Rokunited (Oct 23, 2012)

Thanks for the response and insight. Looks like this is something I need to hold off on. Considering I'm a complete newb better start off with xray films. Thanks gsp!!


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## goldsilverpro (Oct 23, 2012)

Rokunited said:


> Thanks for the response and insight. Looks like this is something I need to hold off on. Considering I'm a complete newb better start off with xray films. Thanks gsp!!


X-ray film isn't much easier. Why not start with karat gold? It's about the easiest.


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## mjgraham (Oct 23, 2012)

I had collected one of these devices a while back, I figured it would be hard to deal with, glad to know.


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## Auful (Nov 19, 2012)

I have two of these silver traps, both acquired from a previous job. One of them had been in place for at least a year before I came to work there. It weighs ~32 oz. It has been fully dry for a year. It smells of sulfur and an acetic acid-like odor. I can see some rust-colored metal, gray powder and black powder with some extremely hard-packed pieces. I have melted about 1/2 oz of silver, in small amounts, from the powders, in a crucible with borax. The melts are very difficult and leave a hard, black varnish on the silver button. I am disappointed to discover the trap is difficult to process. If you are able to provide more specifics about the type of furnace, torch, fuel you use, I would much appreciate it. Is there any other information available for instruction on processing these? Wanna trade some of the silver for helping me process this? I am very new at refining. Thanks


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## Westerngs (Nov 19, 2012)

> Is there any other information available for instruction on processing these?



Read GSP's post above. I have dealt with many thousands of these in the past and GSP's post is as good advice as you are going to get. These are not easy to smelt, but he gives you a good recipe for fluxing.

Sad to say, your best option might be sending the material to a smelter.


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## Auful (Nov 19, 2012)

Westerngs said:


> > Is there any other information available for instruction on processing these?
> 
> 
> 
> ...



Thanks for the quick response. Do you have any smelters in mind? Do you know of anybody who might trade some of the silver recovered in payment for processing this? I have spoken to a couple of refineries. They don't want to touch this silver trap, probably because of the difficulties you and GSP have outlined. 

If I choose to do this myself, I don't really have a good furnace set-up yet. I am just using a mapp/propane bernzomatic 8000 gas torch and crucible/fire bricks. I had been using only borax but will add sodium carbonate, now, as well. Any preference of crucible type? What is the preferred ratio of borax:sodium carbonate? Fluxowder mix? I just joined this forum so am off to do some much needed research on the many fascinating topics posted here! Thanks


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## Westerngs (Nov 19, 2012)

I would try PETAG Corporation petag.net if they can't help you, they probably know someone that can.

as for flux, I would start with this and adjust after seeing how the smelt went:

1 lb silver bearing material
65 grams boric acid
130 grams soda ash (sodium carbonate)
195 grams borax
65 grams sodium nitrate
a rod of rebar (large enough so you can pull it out with tongs before pouring the smelt into a mold)
Heat to about 2200F

use a clay graphite crucible. The crucible should be large enough so it is only about 1/4 to 1/3 full because the sodium nitrate will make the flux "boil" so that it rises in the crucible once molten.

I will warn you, if you have never smelted anything in the past, you should not try to smelt this. Smelting anything is dangerous if you have no experience. You need the right protective equipment as well. Safety glasses, UV protective faceshield, kevlar gloves, aluminized leather coat, steel toed work shoes and a good air purifying respirator are all a minimum must have.


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## Auful (Nov 20, 2012)

This sounds difficult to smelt. I will check out that smelter or maybe I will just melt it in smaller portions like I am doing now, until it is finally all processed, instead of attempting a large amount at once. GSP mentioned that the chemical process to refine this would be a mess. After research, I wonder if the contents of the silver trap could be dissolved in HNO3, the solution, filtered and washed and then silver dropped with NaCl. I know toxic hydrogen sulfide would be given off as the Ag2S is exposed to the acid, so a fume hood would be required. I have already refined a small amount (abt 2 gm) with HNO3, filtering, washing and cementing with Cu, but I got a lot of copper contamination in the silver (so it will have to be further refined.) Would using NaCl help diminish this copper contamination. Forgive me for my inexperience. I know I have yet a lot to learn but thanks for any advice offered.


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## Westerngs (Nov 20, 2012)

If you are intent on doing this chemically, dilute Hydrochloric may be a better way to go than nitric.

Hydrochloric would dissolve the iron and not the silver. The silver may have a thin layer of silver chloride on it.

It would take a lot of hydrochloric.


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## Auful (Nov 20, 2012)

Westerngs said:


> If you are intent on doing this chemically, dilute Hydrochloric may be a better way to go than nitric.
> 
> Hydrochloric would dissolve the iron and not the silver. The silver may have a thin layer of silver chloride on it.
> 
> It would take a lot of hydrochloric.



Ah yes, thank you. Ag2S would be converted to AgCl (s) and the elemental Silver would remain intact, while forming Iron Chloride (soluble), right? Thank you! I might experiment with this method a bit because I don't think I am going to be able to generate enough heat, safely, to melt this 32 oz mixture at once. This forum is great. I just discovered it yesterday and have been spending waaaay too much time already reading it.


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## Auful (Nov 21, 2012)

Monday I placed 6.7 grams of the silver trap mixture in a small crucible and calculated out appropriate masses for borax, soda ash and silver nitrate based on the amounts Westerngs posted (I have no boric acid) and added those to the mix. I melted the mix with a propane torch in a small silica crucible placed in a make-shift firebrick furnace. I was able to reclaim a 3.4 gram silver button. I was thrilled. I am still unsure if the black glass-like slag contains silver (especially silver sulfide) so I am storing it for further study. I didn't add extra iron, but relied on the already evident iron in the mix, so perhaps this slag contains some Ag2S. 

Today I attempted a 60 gram batch in a bigger graphite crucible. Again, I mixed in the appropriate flux amounts, minus boric acid. After about 90 minutes a solid pellet remained in the crucible , but I stopped and poured. The black glass-like slag shimmered with what appeared to be very fine silver flake. The pellet was very dense, but consisted only of gray powder and scattered isolated silver spheres. I was disappointed but believe, as I stated in an earlier post, I simply am too naive or don't possess a suitable furnace for this amount. I was able to melt a nice pellet, later, out of a small piece of the previous dense pellet, so I know it contains silver, I will just have to melt it in smaller batches. When that is accomplished, I will post the yield. 

I am still going to try HCl on some of this mix to see if this is a nicer way to reclaim the silver. Thanks for the advice!


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## butcher (Nov 22, 2012)

Some silver reactions, roasting reactions, melting reactions.

Sulfides can be hard to convert,

Roasting in air or oxygen before melting can also help to convert sulfides to sulfates and in more air to sulfur dioxide gas and silver oxides (although complete conversion can be a little hard to achieve).
Ag2S + 2O2 --roast--> Ag2SO4
2Ag2S + 3O2 --roast--> 2Ag2O(s) + 2SO2 (g)

Iron mixed with the silver sulfide in high heat (roasting and then in melt), the iron will take the sulfides from the silver as well as gases of sulfur and sulfur dioxide gases forming from the reaction
Ag2S + Fe --> 2Ag + FeS
Of course the reaction above is over simplified (as I am not sure of doing the formula with gases involved)

Besides iron sulfide iron sulfate and several other reactions can occur as these sulfur gases release and oxygen and iron react in the heat.

The iron will burn with the free sulfur to form iron sulfide
Fe + S--> FeS

Iron can also help in the roasting process as Iron sulfides form from free sulfur and sulfites in the rich sulfur and sulfur dioxide gases, further heating will drive off free sulfur and sulfur dioxide gases as long as enough oxygen and air is exposed to the fine powders during the red hot roast >700 deg C.
3FeS + 5O2 --roast--> Fe3O4 + 3SO2 (gas) (here magnetite is formed)
If roast is taken farther
4Fe3O4 + O2 --roast--> 6Fe2O3 (here magnetite is converted to hematite)

If not enough air is provided or there is a reducing environment, in the rich sulfur and sulfur dioxide environment the iron pyrite can form pyrrotite also called desulfurizing
FeS2 --> Fes + S(g)


More noble metals will give up the sulfide and sulfur to base metals like iron in the chemistry of a melt, so here having enough iron in the melt can be an important part of the flux.
Ag2S + Fe --melt--> FeS + 2Ag

The iron sulfide will go into the slag glass from the flux.

A torch in a bigger melt would not get hot enough and keep the melt hot enough long enough to complete conversion and for the silver to mix well and collect together getting and keeping the crucible hot enough is another problem as it is robbing the melt of needed heat. A furnace melt would be needed.



More interesting reactions 

Ag2SO4 + 2NaCl --Fusion--> 2AgCl + Na2SO4
Ag2S + 2NaCl +O2 --roast--> 2AgCl + Na2SO4
-------------------
Ag2S + 2O2 --roast--> Ag2SO4
Or
2Ag2S + 3O2 --roast--> 2Ag2O + 2SO2

Ag2SO4 + 2NaCl --roast--> 2AgCl + Na2SO4
Na2SO4 water-soluble
AgCl can be converted to silver

Silver chloride conversion methods:

Silver chloride zinc and dilute HCl
2AgCl + Zn + HCl-(H2O) --> 2Ag + ZnCl3 + H2 + H2O
Or
Silver chloride dilute sulfuric acid and a bar of iron metal
2AgCl + Fe + H2SO4 + H2O --> 2Ag + FeCl2 + FeSO4 +(?)H2O
Or 
Silver chloride sodium hydroxide and Karo syrup
2AgCl + 3NaOH + C6H12O6 --> 2Ag + 2NaCl + C6H11O7 + H2O
Or
Silver chloride sodium hydroxide and hydrogen peroxide
2AgCl + NaOH --> Ag2O + NaCl (and then) Ag2O + H2O2 --> 2Ag + O2 + H2O


I am getting tired and probably making mistakes so check the reactions and formulas, some equations may need balancing


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## Auful (Nov 23, 2012)

Butcher,

Thank you! There are many possible combinations of reactions. I am studying those! I was able to melt some more of the dense pellet from earlier in the week and have, so far, claimed 28 grams of silver from the original 60 grams of silver trap mixture. I accidentally spilled during a pour today. The silver oozed between the cracks of my firebrick furnace and hardened into a nice 12 gram sculpture. The button weights ~16 grams. I think there are a few grams more, leaving about 50% yield. I realize this silver likely has to be further purified for a final yield. That will require constructing an electrolytic cell at some point. I am studying hard to learn how to do that.


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## Martha (Jun 8, 2017)

Hi there
I have a Silver Trap Windows Series recovery unit
Available immediately
Let me know if you're interested
Thank you
Richard


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## Martha (Jun 8, 2017)

Martha said:


> Hi there
> I have a Silver Trap Windows Series recovery unit
> Available immediately
> Let me know if you're interested
> ...


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## Transam66 (Feb 4, 2018)

Hi guys. Been lurking a while but i have some free time now and thought this is something i wouldnt mind having a go at. If anyone has a trap they dont feel like processing, please let me know and we can talk numbers. Thanks. Matt


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## Auful (Feb 4, 2018)

Martha said:


> Hi there
> I have a Silver Trap Windows Series recovery unit
> Available immediately
> Let me know if you're interested
> ...



Missed this post when it was posted. I’m game. PM sent.


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## FrugalRefiner (Feb 4, 2018)

Don't hold your breath waiting for a reply. Martha hasn't been back since he posted that on June 8, 2017.

Dave


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## Auful (Feb 4, 2018)

FrugalRefiner said:


> Don't hold your breath waiting for a reply. Martha hasn't been back since he posted that on June 8, 2017.
> 
> Dave


I figured. I have processed a few of these since getting a proper furnace. They are a challenge and the yield varies a great deal; oftentimes they are mostly iron.


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## rickbb (Feb 6, 2018)

I've tried a few iron exchange cartridges, one worked ok, by ok I mean I recovered a few ozt. of silver. :wink: 

The last one I tried I just made a mess and donated it all to the waste hauler.  

The hobbyist/home refiner will never make a profit out of them. But like me you learn and get a some shiny bars.


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## Transam66 (Feb 6, 2018)

Bummer. If anyone hears of any for sale, please let me know. Im not in it for the money.... just bordom and curiosity getting the better of me lol


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## Julianwelch (Sep 27, 2019)

Hi there

I have one of these silver traps that has been used for over 15 years in a Chiropractic clinic taking spinal X-rays, and am wondering if there’s anything I can do with it, or if anyone wants to try and retrieve any silver from it. I also have approximately 100kg of old X-ray films if anyone knows any UK recycling companies that might pay cash for them..?

Thanks in advance 
Julian


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## Auful (Sep 27, 2019)

Julianwelch said:


> Hi there
> 
> I have one of these silver traps that has been used for over 15 years in a Chiropractic clinic taking spinal X-rays, and am wondering if there’s anything I can do with it, or if anyone wants to try and retrieve any silver from it. I also have approximately 100kg of old X-ray films if anyone knows any UK recycling companies that might pay cash for them..?
> 
> ...



PM sent


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## anachronism (Sep 27, 2019)

I might know a UK recycling company... 8) 8) 

Jon


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## rickbb (Sep 27, 2019)

If it's been in use for 15 years it's iron has long ago been dissolved and you have been flushing silver down the drain for at least 12 of those years.


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## kurtak (Sep 29, 2019)

rickbb said:


> If it's been in use for 15 years it's iron has long ago been dissolved and you have been flushing silver down the drain for at least 12 of those years.



Correct - IF (big if) he has never replaced the iron media that cements out the silver

I would assume "the trap" has a cartrage & "the trap" comes with instructions as to when the cartrage needs to be replaced

The question is - has he been running the same trap with the original media for 15 years - or has he changed out the media during the 15 years of running the trap

He doesn't say

If he has changed the media over the years he has lots of silver --- if he has never changed the media he has lost a lot of silver

Kurt


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## Julianwelch (Sep 30, 2019)

Sorry been away.....I have never touched the trap for 15 years, having said that it was a seldom used X-ray processor, maybe on average once a week if that makes any difference......


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## Julianwelch (Sep 30, 2019)

anachronism said:


> I might know a UK recycling company... 8) 8)
> 
> Jon



I’m all ears Jon?!


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## rickbb (Oct 2, 2019)

Julianwelch said:


> Sorry been away.....I have never touched the trap for 15 years, having said that it was a seldom used X-ray processor, maybe on average once a week if that makes any difference......




It still sat in the fixer solution covering the iron mesh core. Fixer is acidic and will continue to dissolve away at that iron whether you are processing film or not. Not to mention just leaving it in water alone will rust that iron away as well. 

You should replace those cartridges at least once a year. 


I used to get one once a year from a local doctor's office. He only used it a few times a week. Half the iron was gone every time.


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## Jonnyboy (Mar 21, 2020)

Hey guys, newest member here! Lol, which I'm sure you all know also means ding ding questions... But I gotta know (please) . I was reading about this trap unit online, and then stumbled across this discussion you guys had a while back, and I was wondering how did you guys get the spent trap unit? Is this something that gets thrown out by folks in the medical field? Or is it because you guys smelt them out for doctors for a few? Sorry, but I am totally intrigued by this... it's interesting aaaannd I would totally go dumpster diving to find one (I'm just kidding I don't have the means to remove the silver anyways) I did not know until about 30 minutes ago that silver was even used in imaging!


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## rickbb (Mar 23, 2020)

You have to know or otherwise have a deal in place to get the cartridge's with the doctor, etc.. 

Most offices get the units for free by letting the people that supply the units recover and keep any silver.

But all that is no more, almost all x-rays nowadays are digital, no film and no silver.


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## rsnobles2 (May 4, 2020)

Correct! I'm new here as well, and also a retired chiropractor. I came here because I have 300lb's of x-rays and 1 of these filters I am currently trying to process at home as a hobby. I believe it would be more cost effective to sell the xrays off in 5lb lots on ebay than to continue refining at home. I am using the Clorox/Lye/Sugar method. I ended up here with questions about how to recover silver from this trap and it sounds like it may not be worth it. But, as stated above, whenever I needed a new trap, I received a discount for submitting the used, or paid full price for a new one. A lot of chiropractors still use film in office, as well as smaller family practices. Most are also unaware that films can be sold for their silver content.


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