# I have a Silver and Copper Question



## ThePierCer (Mar 19, 2008)

I was woundering the best way to discolve Silver without using Nitric. Will AP work? I also have a lot of Copper mixed with my Silver, and was woundering the best method to percipitate just the Silver, then the Copper after all the Silver has dropped.


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## Noxx (Mar 19, 2008)

If you don't do any electrolysis, nitric acid is the preferred method.


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## ThePierCer (Mar 19, 2008)

Are you saying Nitric is the only way to disolve Silver?


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## Lou (Mar 19, 2008)

Reasonably speaking, yes.


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## ThePierCer (Mar 19, 2008)

Ok..I guess Nitric it is. Now what will disolve just the Copper and leave the Silver? I have a lot of Copper mixed with my Silver.


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## Noxx (Mar 19, 2008)

It will dissolve both.


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## ThePierCer (Mar 19, 2008)

I know Nitric disolves both, I need something that will disolve the copper and not the silver. I know Copper is used to drop Silver, thats why i need something that will only do the Copper.


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## Anonymous (Mar 19, 2008)

Would plating the copper out in a cell leave the silver? A copper sulfate bath and a mixed silver copper electrode with a pure copper electrode.
?


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## agpodt77339 (Mar 19, 2008)

I think muriatic acid would dissolve the copper, but not the silver. It might be a very slow reaction if the silver and copper are in solid metal form, but if they are powder, it would go reasonably fast.


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## Harold_V (Mar 19, 2008)

Maybe I've missed something in my many years of processing precious metals, but I have serious doubts that I have. 

Nitric acid is used to dissolve both copper and silver-----then copper is used to selectively precipitate the silver. I know of no other method that works, not only as well, but at all (keep in mind I am not discussing the processing of silver chloride). You can not selectively dissolve only the silver or copper unless you digest the silver in boiling concentrated sulfuric acid. Don't go there. 

Don't get caught up with the idea that you can do this electrolytically. That's a big mistake. Electrolytic parting works very best when you deal with one major element, with just traces of contaminants. It works poorly, if at all, when those conditions are not met. It is clearly a waste of time and resources to try, unless your objective is research. If you're interested in processing silver, I strongly advise you to follow accepted practices-----do not attempt to re-invent the wheel, which is sufficiently round. 

I realize you're going to do it anyway-----because we rarely learn from the hard experiences of others. I was no different. 

Consider yourself well warned, and remember my prophetic words when your attempts fall flat. 

Harold

edit: removed one word, with no change to meaning of content.


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## goldsilverpro (Mar 19, 2008)

> I know Nitric disolves both, I need something that will disolve the copper and not the silver. I know Copper is used to drop Silver, thats why i need something that will only do the Copper.



People in hell want ice water.


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## Harold_V (Mar 19, 2008)

goldsilverpro said:


> > I know Nitric disolves both, I need something that will disolve the copper and not the silver. I know Copper is used to drop Silver, thats why i need something that will only do the Copper.
> 
> 
> 
> People in hell want ice water.



Chuckle!

Each have an equal chance of achieving their goals, eh?  

Harold


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## ThePierCer (Mar 20, 2008)

Thanks Harold, I've always listened to everything you've said (wrote)

The fact is I am trying to learn from a mistake I made a year ago when I ended up with a 6oz bar of Silver riddled with Copper. It’s been sitting on a shelf while I learned more about the subject. 

This line of questioning arose from watching Steve’s AP demonstration in which the Copper and other base metal were dissolved, leading me to question weather I could use that process to get the Copper out of my Silver and precipitate them separately. 

I still have a around 50 lb’s of Silver plated Copper wire that I wish to process. I initially tried quick dips in Nitric. Admittedly, I used very poor techniques and ended up making a mess of the whole process.


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## Harold_V (Mar 20, 2008)

ThePierCer said:


> I still have a around 50 lb’s of Silver plated Copper wire that I wish to process. I initially tried quick dips in Nitric. Admittedly, I used very poor techniques and ended up making a mess of the whole process.


Perhaps you've read my comments about AR not being a stripping process, but a refining process. Realize, of course, that there are exceptions, one of which is when stripping non-metallic objects. The reason for that exception relates to why you can't do what you just suggested. 

Assume you are successful in stripping silver from copper wire with nitric acid. It will, and does, dissolve, of that there is no question. 

How then, would you recover the silver? 

I'm assuming you're dissolving only the silver, none of the copper. 

There is no such thing as a quick removal of the wire from your stripping solution. The moment there is equilibrium, silver will start to precipitate on the wire, eventually consuming it entirely, or stopping only when all of the silver has been precipitated. In essence, you will consume the wire, or leave some behind as a contaminant.

One might suggest that they can keep the level of free nitric high enough to prevent precipitation----but that's flawed thinking. The moment the wire is removed from solution, the small amount of remaining acid (on the wire) is immediately consumed. The dragged out solution bears silver nitrate, which immediately reduces to elemental silver on the wire. Some of it won't slough off----and often will adhere doggedly. 

What you've managed to accomplish is to swap your silver about, but not effect a complete separation. 

Want to remove the silver from that wire successfully? 

Use a sulfuric cell. 

Or----place the wire in nitric, and allow all the silver to dissolve, then leave the wire in so it will precipitate the silver. Given a good balance of nitric and water, you may be successful in recovering the silver. You'll lose some of the copper, but with luck it may reduce the sliver nitrate such that it will rinse right off. Be advised that the silver may not dissolve uniformly, so you may not achieve the desired goal. 

Harold


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## GeeDub (Feb 24, 2009)

Anyone try the method Henos posted on this thread?
http://goldrefiningforum.com/phpBB3/viewtopic.php?t=1609

(Jeez it takes a long time to go through this entire forum.)


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## jamthe3 (Feb 24, 2009)

I couldn't understand what he was saying. Partly due to a language difficulty, mostly due to my own ignorance. Since I first saw it soon after joining the forum I was at least smart enough to take Harold's advice and slowly read Hoke's book, so his post makes a bit more sense to me; although I still don't follow what he is trying to articulate at the end.

Am starting to get a real keen interest in the sulfuric cell though, both for gold and silver. I've got a lot (at least a lot to me that is) of silver plated wire and have a sense that the cell will probably be a bit to my liking for a number of reasons.

Cheers,
John


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## Harold_V (Feb 24, 2009)

One of the things I may have neglected to mention in the past is dealing with silver plated copper. It's not really economical to process, and if the silver is on fine copper wire, it's a real problem recovering the silver without destroying the copper for reason. 

I used to melt silver plated items, assuming they are on pure copper. By melting, the silver is distributed within the copper, which is cast as an ingot and used to recover silver from silver nitrate solutions. That way, you get use of the copper, and end up with the silver as a bonus. You have the cost of melting involved, but it's still a great way to end up with usable copper and recover the silver in the bargain. You might consider that idea if you deal with inquartation. 

I never operated a sulfuric stripping cell, but GSP has discussed the difficulty of recovering silver from one's use. Might be a good idea to check for his comments, or perhaps to ask directly of him what you might expect. I hesitate to comment due to lack of experience. 

Harold


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## Anonymous (Feb 24, 2009)

I have some silver plated stuff, I am going to try and remove the plating with molten zinc, if that doesn't work I am going to try molten lead, then remove the silver from the lead with zinc.

Will let you know.

Jim


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## GeeDub (Feb 24, 2009)

jamthe3 said:


> I couldn't understand what he was saying. Partly due to a language difficulty, mostly due to my own ignorance.


Nah, I don't think it was your ignorance, I think it was the language. I had a helluva time figuring out what _I thought _he was saying. That's why I phrased my post the way I did; not "try this method", but "has anyone tried". 
I thought (hoped) one of the more experienced members would have recognized the basic theory of it as a version of a process they had used.
-G


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## goldsilverpro (Feb 24, 2009)

The 95/5, sulfuric/nitric is an old common method for stripping silver from copper. It definitely dissolves the silver and hardly touches the copper. It really does work. But, you have to keep the water out of it. When you're not using it, keep it well covered. It soaks up moisture from the air, like crazy. It is found in every electroplating text. It's usage, however, is not for recovery of the silver, but for removing faulty silver plating so that the copper part can be re-plated. The cost of the part, most likely, greatly exceeds the value of the silver. The part is all important. Screw the silver.

This formula belongs the the plating industry. I have never seen it taken seriously for the recovery of silver. First of all, it's a damned dangerous system. The H2SO4 decomposes the HNO3 and you get fumes. And, sulfuric loves to eat human tissue. If the silver is thick, the plating books tell you to heat it to 180F. This makes it 10 times more dangerous.

Lastly, how do you get the silver out of the sulfuric? There are ways to do it, but they're not fun. Some ways are dangerous. Most are wasteful.

It would be interesting to know how much silver you could dissolve in it. I would imagine quite a bit. It's similar to dissolving silver from mining dore' bars in hot concentrated sulfuric. I may be way off but, without looking it up, I'm thinking 100 oz/gallon. Also, a safe, clean, efficient method for recovering the silver would be nice.


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## jamthe3 (Feb 25, 2009)

Thanks for those posts guys.

Harold, when you melted silver plated copper, did you use any kind of flux or charcoal cover perhaps; and, if so (the flux that is) would it be okay to ask what you used?

Thanks,
John


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## Harold_V (Feb 25, 2009)

No, no flux, John. I melted the mess, then poured what were random ingots that weighed maybe three or four pounds. What I used was a 100 oz ingot mold for casting silver ingots, but only because I had it. You can use pretty much any form that suits your needs, assuming it has draft, so the copper can't key to the mold. 

You can make an excellent mold by welding ends on some channel or angle iron. Make sure the material is cut with a taper so the top of the mold is wider than the bottom after the plates are welded in place. 

Be careful to blacken the mold, especially if it's made of steel, and when you pour the copper, move the stream about so it doesn't play in one spot, superheating the area. That is often the cause of soldering to the mold. 

Flux would have created cleaning problems unless I'd have poured first to a cone mold, then re-melted after cleaning the slag from the buttons. For my purpose, that was far too much work. My only interest was in getting the copper in a form that was functional for recovering silver from nitrate solutions, pretty much as I alluded. I wasn't overly concerned that the copper formed a little oxide. I'd simply plunge the hot ingot in cold water, which readily sheds the oxide scale, leaving you a pretty nice looking piece of copper. 

Harold

edit: corrected spelling


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## jamthe3 (Feb 25, 2009)

Thanks Harold, was curious.

Melting copper wire is sometimes a pain, assumed silver plated copper wire would be equally frustrating (but then again my furnace pales in comparison to the one you made, really enjoyed the pictures I found of it BTW) takes forever and tons of heat. Tried w/ a charcoal cover once or twice and didn't see that it helped much. Really like that idea to plunge in water though.

John


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## GeeDub (Feb 25, 2009)

goldsilverpro said:


> The 95/5, sulfuric/nitric is an old common method for stripping silver from copper. It definitely dissolves the silver and hardly touches the copper. It really does work.


Well this sounds like something better left to being a bench top learning experience.
Which means... I will probably try it some day.

Just to get it straight, is it 95% of 95-96% concentrated Sulfuric with 5% of 70% Nitric?
Thanks,
-G


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## goldsilverpro (Feb 25, 2009)

G... That's right, 19 parts of concentrated H2SO4 + 1 part concentrated HNO3 - all by volume. For 1 liter, it would be 950 ml of conc. H2SO4 + 50 ml of conc. HNO3.

To get the silver out, it sounds like Henos dilutes the acid, 10 to 1, and then cements out the silver on copper.


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## Sylar (Feb 25, 2009)

After the recovery of the silver from the diluted sulfuric acid (and it tests negative for silver ions) you can just concentrate it again by boiling it to the original volume. 
Boiling point and specific weight can be tools to verify the aquired concentration.

I'm also interested in the amount of silver that can be dissolved by this method. I recently had to dissolve a fair amount of copper for the recovery of the silver on electrical contacts ... seems applicable to this aswell.


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## beaks (May 21, 2009)

quote----"Lastly, how do you get the silver out of the sulfuric? There are ways to do it, but they're not fun. Some ways are dangerous. Most are wasteful."----end quote


Just add some muratic and nitrate then heat it up a little and use the stuff on gold or silver or whatever trips your trigger until it is saturated then drop the values as you normally do.

it works for me when i have to do it, i dont lose any metal and its safe as long as i dont get stupid.

you can mix these chemicals at any time during processing and you get AR, it may not be perfect but it gets the job done and you recover your PM's when you need to just like you would from premixed AR.(you may have to add a little more sulfuric but thats no big deal)

the simple answer is always the best(so far anyway LOL)


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## Harold_V (May 21, 2009)

beaks said:


> Just add some muratic and nitrate then heat it up a little and use the stuff on gold or silver or


One does not use a solution you described for dissolving silver. Silver is properly dissolved with nitric acid. There should never be any chlorine introduced unless you desire to recover silver as a chloride, which is not commonly recommended. 

Harold


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## beaks (May 21, 2009)

LOL you are right but i dont care how it comes out as long as it comes out.
converting the chloride to metal is easy so its no big deal for me and you can also sell the chloride at a pretty sweet price.(more than the silver is worth)


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## Harold_V (May 21, 2009)

beaks said:


> LOL you are right but i dont care how it comes out as long as it comes out.
> converting the chloride to metal is easy so its no big deal for me and you can also sell the chloride at a pretty sweet price.(more than the silver is worth)


You've missed the point, and that is sending the wrong message to readers. It DOESN'T come out, not with silver. You can't dissolve silver with chlorine present-----it must be dissolved in nitric alone----then it can be recovered with chlorine if desired. 

Please try to not post information that is misleading, which your statement was. There are many readers with little or no experience that may try to use the information you provided, which, of course, is not true. They may not understand why they have trouble. 

Harold


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## beaks (May 21, 2009)

i understand what you are saying BUT i wasnt talking about dissolving the silver i was talking about recovering it.

all you have to do is filter and rinse it then convert it to metal or dry it and sell it the way it is.

i do it daily with mixed metals and i recover my silver as well as any gold that is in the mix and it works well.

Sure there are other ways that work (better? it depends on who you are and how fast you want to get the job done)

the results are the same as using salt to dump your silver from nitric all you do is filter the AR, recover your chloride, clean it and you are done with the hard part.(its basic chemistry and not misleading at all)

and it works


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## nicknitro (May 21, 2009)

Sorry Beaks,

I would have to agree with Harold on this issue. I have very limited silver refining, and can see flaws in your process. If anything it seems more like a recovery process for later refining. I also would be wary of using sulphuric and nitric and HCL all together, especially with silver. Seems you are begging for bad reactions/compounds. I won't get into the results of say 60/40 sulphuric/nitric with many organic compounds encoutered in refining, but most are undesireable.

At any rate, don't take it to heart. I could definitely learn a lot more about the silver refining process, and that is why I come here regularly. To learn, and share. I hope you do too.

Sincerely,
Nick


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## beaks (May 26, 2009)

I just checked out the last post and its kind of funny LOL

what you get when you combine nitrate with sulfuric acid is nitric acid when you add hcl you get AR.

I learn something new every day but i dont make a habit of learning the same thing every day.(i was born but i wasnt born yesterday)

like i said in the other post (this is bare bones, basic chemistry)

if he doesnt want to deal with AR he could add nitrate to his sulfuric and end up with nitric acid then either use it again or dump the silver with salt or copper.

why make something more complicated than it is?
and trying to make me look like a moron over an ego trip is just wrong.


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## nicknitro (May 26, 2009)

Beaks,

If you feel it is safe to mix these acids together, just to drop silver form a solution, thats fine. I was only suggesting that it may be an improbable solution to most who have organics mixed with their acids. Many sulfuric cells contain glycerin, though it has been stated on many other posts that it is not necessary. I would strongly disagree to someone adding nitric acid to a solution of sulphuric acid that contained this, no matter what concentration. 

I mean really, how many people add three organic acids together in a refining process? I have read numerous posts for the past year and haven't seen any. Most call for incineration between acid wash switching. Usually so they don't dissolve the PM involved, but the method yoyu suggest seems sloopy at best. 

Even you agree from your prior post it is a recovery method at best. Why waste your time converting a "known concentration of Ag" to AgCl???? Do you work for Kodak? Why not just sell the Silver metal, or hold on to it?

Nick


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## Platdigger (May 26, 2009)

Nick, what was being discussed here was disolving silver in sulfuric.
Chris mentioned the 95/5 method with 5 percent being nitric.
He also mentions a 10 to 1 dilution with water, and then the silver being cemented to copper.

Beaks offers another method of adding hcl (there is already some nitric in the mix) to get the chloride.
Not saying which is best, but I don't see any special danger of having these three acids together.
I mean, it is a common practice to add sulfuric to AR to eliminate any lead in solution. Yes?

BTW, these are not "organic" acids. 
Randy


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## beaks (May 26, 2009)

thank you randy for the explaining, i admit i dont do a good job of it myself most of the time.

i am more "hands on" and usually let someone else deal with putting it in print when it comes to work related subjects.


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## nicknitro (May 27, 2009)

PlatDigger, 

Good Catch on the organic acids. I still stand by what I said, his process doesn't make sense to me, and that is fine. We will just have to agree to disagree. More than likely I was just offended, and am baseing decisions on emotion.

Thanks for adding the third party perspective, it is appreciated.

Nick


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