# Question regarding silver traps from x-ray processors



## SilverHound (Dec 27, 2015)

Hi All-

New to the forum. I have dabbled with gold and silver refining for a while now and have a question. I have been given (2) x-ray filter traps. They were both in service for at least 2 years each and both are loaded with silver. My question is can i use HCl to remove the steel mesh that is left before melting it into shot and dissolve it in nitric acid. Will the HCl react with the silver to form AgCl? 

Thanks in advance


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## torscot (Dec 27, 2015)

Yes, You will have problems with silver chloride if you try to dissolve with nitric after HCI. Silver chloride will form a coating on the silver that the nitric cannot dissolve and that's the end of reaction. It seems no matter how well you wash it after HCI it will still cause problems.

I have heard of incinerating your material after treatment with HCI to remove the chlorides. If you don't get it all and your reaction still goes bad. The silver chloride can be dealt with but why create a problem when you don't have one now.

I would strongly suggest staying away from your material with HCI. Someone else I am sure will chime in with a method to look after the steel. I have not had to deal with that problem yet...........................

EDIT
I just re read your question after posting. If you melt your silver after treatment with HCI. the chlorides are gone. Should not be a problem if you do it that way. I mis read that part when I first replied. So long as you melt it you should be good to go.


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## SilverHound (Dec 27, 2015)

torscot said:


> Yes, You will have problems with silver chloride if you try to dissolve with nitric after HCI. Silver chloride will form a coating on the silver that the nitric cannot dissolve and that's the end of reaction. It seems no matter how well you wash it after HCI it will still cause problems.
> 
> I have heard of incinerating your material after treatment with HCI to remove the chlorides. If you don't get it all and your reaction still goes bad. The silver chloride can be dealt with but why create a problem when you don't have one now.
> 
> ...





Thank you for your reply. 
I am going to try the HCl and then melt it in a small batch to see what may happen


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## g_axelsson (Dec 27, 2015)

I think you should do a search on the forum.

If my memory doesn't fail me I think the processing of the filter canisters is usually recommended to be done by smelting together with rebars. In that case there are no reason to treat the filters with HCl to remove the iron. I think there are silver sulfides that needs the iron to transfer into silver and iron sulfide.

Incineration to remove silver chloride...??? :shock: Never heard about that before. Can you give a reference for that, torscot?
Silver chloride heated enough will go up in white toxic smoke, not the best way to recover silver.

Göran


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## Auful (Dec 27, 2015)

Here is the thread to which I think Göran refers: http://goldrefiningforum.com/phpBB3/viewtopic.php?t=15985
Edit: corrected url syntax


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## SilverHound (Dec 27, 2015)

Regarding the rebar, do I simply place in the crucible while getting temp to melt and remove before pour. Sorry if a bad question.


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## torscot (Dec 28, 2015)

Goran, I didn't say to remove silver chloride, It was "to remove chlorides" any remaining traces of the HCI. I Burn it, than wash it again in distilled water. You are absolutely correct that your silver chloride will go up in smoke. There may be minute amounts of silver chloride created during that treatment, but the loss is minimal compared to the amount of work and loss you have to go through when your nitric gets contaminated when you are trying to dissolve your silver. I don't use those two acids on the same batch unless I want silver chloride. 

The incinerating info was from a post on here. I will try to find it again. It was a few years ago that I saw it, so It may be difficult to dig it back out. I'll check my notes in my workshop to see if I recorded the source when I have some time after work today.

It looks like someone posted a link to the info he needs to help recover his metal. I knew the info had to be here. I just jumped in because I didn't want him to dunk it in HCI then nitric and go "oops" That's no fun at all.
Rob.


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## rickbb (Dec 28, 2015)

I've found that if you simply rinse the iron cartridge well after cutting it apart with a hack saw blade you won't need to bother with removing any iron.
Most of what you get in the rinse will be silver. The best method for converting any silver chloride to silver metal would be to put it in dilute sulfuric with some iron nails and gently stir it. Some use a tumbler like a rock tumbler.

If you use that method having some iron in the concentrate will actually be a good thing.

LaserSteve has some excellent videos on this process on his web site.


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## g_axelsson (Dec 28, 2015)

SilverHound said:


> Regarding the rebar, do I simply place in the crucible while getting temp to melt and remove before pour. Sorry if a bad question.


You remove the rebar after the reaction is complete before you pour.

These filters have been discussed a number of times on the forum, do a search, read a lot of threads, even the ones that doesn't discuss the filter will give you answers on questions you didn't know you have.

I haven't run into these filters but it sounds like rickbb have done it. Listen to the people that have practical experience of successful recover silver from them.

And I will quote GSP from the thread Auful found, it's a good thread but there are more on the forum. Dig and you will find.


goldsilverpro said:


> 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.


Keep safe!

Göran


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## rickbb (Dec 29, 2015)

I get a couple of them a year from a local small doctors office. I've tried several methods but I wind up going back to the simple.

Cut them down the middle length wise with a hack saw in a 5 gallon bucket. Rinse it lots, and lots, and then some more while pulling all the windings apart to get it rinsed well. 

You'll end up with many buckets of water but let it all settle and siphon off all the water until you get all the black sediment in one small container and then process/refine with the method of your choice.

This removes as much of the base metals as possible before you do any dissolving/smelting. You'll have a higher quality and higher yield this way. If you try to dissolve the whole cartridge you'll end up with gallons and gallons of acid waste and contaminated silver to try and clean/refine.

Always concentrate it down mechanically first to keep the volume of chemical waste small.


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## Auful (Dec 29, 2015)

I'm curious: since most of the base metal is in the form of iron and iron oxide, how does washing with water rid the sediment of these since they are both insoluble in water? Thanks.


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## kurtak (Dec 30, 2015)

SilverHound

You need to smelt this material period 

Before smelting - wash the material real good to rid it of chems & then dry it 

You need a gas fired furnace (you will destroy a electric furnace if you try to use an electric one) & you also need a cone mold & you want "good" quality crucibles
like these :arrow: http://www.morganmms.com/produtos/cadinhos/salamander-super --- DO NOT trust the cheap one shot crucibles they will not hold up to the flux & the reaction of the sulfur with the iron as the iron reduces the silver sulfide to silver

Here are links to everything you need to know concerning this material 

http://goldrefiningforum.com/phpBB3/viewtopic.php?f=50&t=20201&p=207306&hilit=picture+fixer#p207306

http://goldrefiningforum.com/phpBB3/viewtopic.php?f=49&t=12404#p122640

http://goldrefiningforum.com/phpBB3/viewtopic.php?f=49&t=21409&p=220999&hilit=smelt#p220998

Edit to add; - Or - you can also use Juan Manuel Arcos Frank's Potassium nitrate conversion method - he provides a complete PDF instruction for it in his first post in this thread :arrow: http://goldrefiningforum.com/phpBB3/viewtopic.php?f=50&t=6167&p=87401&hilit=potassium+nitrate#p53940 

Kurt


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## kurtak (Dec 30, 2015)

rickbb said:


> I get a couple of them a year from a local small doctors office. I've tried several methods but I wind up going back to the simple.
> 
> Cut them down the middle length wise with a hack saw in a 5 gallon bucket. Rinse it lots, and lots, and then some more while pulling all the windings apart to get it rinsed well.
> 
> ...



rickbb

Note what I underlined above - there is no such thing as - "then process/refine with the method of your choice" - or - "before you do any dissolving"

Simply trying to dissolve it after washing the chem out of it (that part you got right) will not give you back all the silver due to the FACT that a large portion of the silver is in the form of a sulfide & wont dissolve - the sulfide "needs" to first be reduced - that is done with ether the iron (rebar) smelting method or Manuel's potassium nitrate method - period - meaning those ARE the choice's --- dissolving (before smelting) is not an option (choice) doing so will result in MUCH of the silver NOT being recovered 

Following the instruction of ether the iron smelt or the potassium nitrate method will give you back ALL the silver & it will do so in such a way that it can go directly to the silver cell - in other words after the smelt it is silver cell ready & no need to dissolve it &/or process other wise

Note - one of the links in my other post (this thread) was a reply of mine to you giving the proper instructions when you first asked about this - please stick to the proper instructions when advising others (or provide links to the proper instructions)

Kurt


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## MarcoP (Dec 30, 2015)

I'm not into reinventing the wheel but would tumbling altogether with 10% sulfuric acid do the trick?
Silver sulfide will convert to silver metal and excess iron will go into solution, filter and evaporate it down to make copperas (reducing agent but also a fertilizer).

Am I missing something? If this wet method could work you'll end up with no waste at all.

Marco


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## kurtak (Dec 30, 2015)

MarcoP said:


> I'm not into reinventing the wheel but would tumbling altogether with 10% sulfuric acid do the trick?
> 
> Marco



That is a method used for reducing silver "chloride" not silver sulfide --- to reduce silver sulfide you need the high smelt temp for the sulfur in the sulfide to react with the iron & thereby cause the reduction

Edit to add; - Think of it this way - you cant use a sulfur based chem to reduce a sulfur based compound in a metal "ion exchange" reaction --- like wise you can't use HCl (to dissolve iron) to cause the reduction of AgCl to Ag as a metal ion exchange reaction --- the HCl will dissolve the iron but it prevents the chloride bond from being broken because it (the HCl) is what causes the chloride bond to be made in the first place --- like wise the 10% sulfuric will dissolve the iron but wont break the sulfide bond

What happens when you pour the fixer solution though the filter with the iron in it is that you are pouring a sulfate solution through the filter - the sulfate solution reacts with the iron reducing it from a sulfate to a sulfide (meaning you still have a complex - but a reduced complex) - the sulfide will now react with the iron "in the high temp of smelt" to break this less complex bond - there by reducing the silver sulfide to silver 

Kurt


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## MarcoP (Dec 30, 2015)

Thanks Kurt,

I knew it is used to convert silver chloride into metal when tumbled with steel (iron). Obviously I need to learn the entire reaction chain as I thought that sulfide replace the chloride and iron would reduce it.

Yes, for chloride I believe to be the better one. In this case I thought I would pick up the reaction half way through. Silver sulfide was there already, iron in the cartridge and some excess of sulfuric.

Marco


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## kurtak (Dec 30, 2015)

Marco 

I just edited my post to better explain it

Kurt


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## SilverHound (Jan 7, 2016)

thanks to all for the valuable info. I am currently assembling the materials necessary to build a furnace.


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