# silver pin in AP?



## Geo (Aug 25, 2011)

i know there's better ways to strip silver plated pins, but has anyone ever tried to digest the base metal out from under the silver plate on military connector pins? these are very thick plated and the silver is suppose to be pure. i have about twenty pounds of these pins out and ready to be processed. since i have plenty of time and can re-use the AP, is this a viable choice? is a stripping cell a better choice?


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## andrew john (Oct 18, 2011)

Hi. Cant say i have tried it before for that but the theary is right and it should work.
good luck m8, let us know how it turns out. 8)


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## nickvc (Oct 19, 2011)

Geo I'm far from an expert on e scrap but the AP approach may be worth a trial, try say 100 grams of pins and a small amount of fresh AP and see if it works. Even if it only removes 50% of the base metals it will reduce the amount of nitric needed to recover the rest and if it does a really good job it will give you silver to feed into a silver cell. I think your right about the silver been high grade and I'm sure GSP could confirm exactly how pure, the anodes are definitely fine silver but I'm not sure if the solutions have any metal additives to achieve decent plating results.


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## Geo (Oct 19, 2011)

i still have all the pins.its a sore spot as i took 1 OZ of small silver plated contacts out of rotory switches and melted into a small anode and tried it in a thumb cell,it didnt work too well.guess it still had too much copper.


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## kelly (Oct 19, 2011)

Geo,
I've tried some silver plated organ buss bars in AP... its a slow process. The bars I had were about 1/8" in diameter and I cut them into 3/4" long pieces. It took about six months, but I ended up with some nice silver tubes. If I had to do it again, I would have just used them to cement my silver nitrate and killed two birds with one stone. It can be done, but I think a silver cell would serve better.
K


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## goldsilverpro (Oct 19, 2011)

Silver cells don't work well at all unless the alloy of the anodes is at least 90% silver. Even then, it creates too much work and chemicals. Best is about 98% silver, or higher. I have run a lot of sterling (about 91% silver, in reality) through a cell but it's really a pain.


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## nickvc (Oct 20, 2011)

Well Geo, GSP hasn't said it won't work but pointed out the need for high grade material for cell refining so I guess as your in no hurry it will do the job and a lot less unpleasant and cheaper than using nitric. Cementation is great way to recover this if you have lots of material going through your processes but could take forever if it's only the odd job.


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## butcher (Oct 22, 2011)

Why couldnt you just use the concentrated sulfuric acid stripping cell (the one used to strip gold)?

Edit to add: If you ran enough silver plate to saturate the acid with silver, the silver should precipitate as a sulfide upon dilution, the silver laden acid could be diluted by pouring it into a bucket of water, (never pour water into concentrated sulfuric acid it may splash out violently), this would give a silver sulfide salt, that melted with rebar to convert back into silver metal.

any thoughs on this?


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## Geo (Oct 22, 2011)

the only argument i can give for this is, i hate working with sulphides as ive not had enough experience dealing with them. i do when i have to but would rather not have to. if the silver does not react to the copper chloride etching, i should have silver foils rather than gold foils, heck ill even take silver powder. i have plenty of AP solution and ill post a pic of the pins i want to try. im even collecting the cemented copper to try a copper cell like the one NoIdea has. i like the idea of removing the copper from any material im working with first. at this point in time nitric acid is at a premium around here as i have to make every drop i use and i find the stripping cell attacks copper at about the same rate as my working material no matter how careful i am at controlling the temperature. gold stripping isnt a problem as far as the copper goes, it just means i have to refine it an extra time. but silver on the other hand almost exclusively needs nitric acid to refine and given the fact that it only absorbs such a low volume of copper makes the idea of removing as much copper as possible beforehand very attractive to me.


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## Palladium (Oct 22, 2011)

I don’t see a reason ap wouldn’t work theoretically. Now feasibility economically is a different question. A gallon of hcl cost $6 and will dissolve about 3 lbs of cu. If you get 1 gram per lb of cu pins then that’s 3 grams of gold, that’s about $160 worth of recovery for $6. It would take 5+ oz of silver to = the same.


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## Geo (Oct 22, 2011)

yes, the math tells it all. the only time i will use new hcl will be the test batch to see if it works ok,after that i will be using the old solution i have stored now (about 10 gallons) i have already cemented nearly 40 pounds of dirty copper from AP so far. im sure theres quite a bit of silver from the old solder mixed with that. ive done well over a hundred pounds of whole boards that had gold plated traces. anyone know how to selectively reclaim the tin from this mess?


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## Palladium (Oct 22, 2011)

I guess you could use fe to drop the tin and then use the ferric chloride to etch the copper on new materials :?:


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## Geo (Oct 22, 2011)

great. ill try that.


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## joem (Dec 29, 2011)

I think this may be the better place to post these questions.
I know A/P will dissolve copper.
so
1. Will A/P dissolve silver?
2. will A/P dissolve brass?

I'm working on this recovery idea of getting silver off of silver plated items and no I do not want to dissolve the whole thing in A/P.
I just came across a simple idea i am going to try, I'll update later.


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## Geo (Dec 29, 2011)

joem said:


> I think this may be the better place to post these questions.
> I know A/P will dissolve copper.
> so
> 1. Will A/P dissolve silver?
> ...



1.AP will not dissolve silver.

2.AP will dissolve brass. brass is mostly copper and zinc both of which dissolve in AP. bronze is normally an alloy of copper and tin. sometimes people silver plate bronze items to be decorative but in all it too is dissolved in AP. if the piece is thick enough you may can save a certain amount of metal if you stay on top of it.


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## Photobacterium (Dec 30, 2011)

Geo said:


> yes, the math tells it all. the only time i will use new hcl will be the test batch to see if it works ok,after that i will be using the old solution i have stored now (about 10 gallons) i have already cemented nearly 40 pounds of dirty copper from AP so far. im sure theres quite a bit of silver from the old solder mixed with that. ive done well over a hundred pounds of whole boards that had gold plated traces. anyone know how to selectively reclaim the tin from this mess?



i dissolved some tin-silver solder in Nitric & HCl to figure out what it was. a long roll of 1/2 inch wide metal tape.

i noticed that the "tin in nitric" did not go well, granted my nitric was about 26.5% based on specific gravity. i got the 'white crap' ... i read more about tin in nitric & some people had documented the white crap - obviously with a more technical name.

the material you want to recover the tin from is - sounds like -
* mostly copper
* silver
* tin

my ultra-reliable reference - Yahoo Answers 8) 
http://answers.yahoo.com/question/index?qid=20080808213804AAbpVAa
"Why does Fe, Zn, Al, Ni, Sn all dissolve in hydrochloric acid
but Cu, Hg, Ag, Au, and Pt doesn't"

if the 40 pounds were rendered into small pieces, or is still in powder form - wouldn't HCl (good old cheap muriatic acid) provide a cost-effective way to isolate the tin from the copper & silver ?

though i'm not sure - once you have dissolved the tin in HCl to create stannous chloride - how do you then convert it to metallic tin ? it sounds like you want to re-claim it, not just remove it from the rest of the collection.

http://en.wikipedia.org/wiki/Tin%28II%29_chloride

"Tin(II) chloride (stannous chloride) is a white crystalline solid with the formula SnCl2. It forms a stable dihydrate, but aqueous solutions tend to undergo hydrolysis, particularly if hot. SnCl2 is widely used as a reducing agent (in acid solution), and in electrolytic baths for tin-plating"
*
how about using an electrolytic cell to plate the tin in the stannous chloride ?*


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## Geo (Dec 30, 2011)

the problem i came to with using hcl to remove the tin (and is still in powder) is when i add the hcl there is still quite a bit of copper oxide mixed with it.as soon as the hcl goes in it turns green then black. the tin could possibly be worth more than the copper and i have a market for these metals. it doesn't need to be pure but it does need to be in a marketable form. the tin seems to precipitate out better if i add some chlorine bleach and then heat, not sure why, but when the solution cools tin crystals precipitate on every surface available.now i need to know how to reduce these crystals to elemental tin.


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## johnny309 (Jan 15, 2012)

Try mixing tin crystals with the rosin used for soldering(colophony) and heat to about 190 degrees Celsius.....You should be able to obtain the metallic form of tin from this operation.
Colophony is a flux just like borax is used for gold(even borax will be well suited for the job).
Just an thought.


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## Geo (Jan 15, 2012)

i didn't think of that.i was thinking since tin has a low melting point, i could use some carbon and flux in a home made crucible.i dont have much yet to deal with as its still in solution but i do have about 10 pounds of dirty crystals i can practice on.


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