Non-Chemical Silver plated scrap for silver recovery

[watcher6880]

I pretty much know how the silver recovery process works using copper as a precipitant but what I wonder is if the silver plated item being used for recovery contains copper itself, how would that work in recovering the silver from the Nitric acid solution? From what I understand, adding copper as a precipitant changes the silver nitrate to copper nitrate, so if the copper is part of the silver plated item being recovered wouldn't that pose a problem?

 

[butcher]

watcher6880,
Here is how I see this.

When we cement silver from a silver nitrate solution, we are depending on the silver dissolved in the solution to come into contact with our copper metal, thus the silver in solution (missing an electron) then takes an electron from our copper metal, then copper is missing the electron dissolves into solution as copper nitrate, this goes on until all silver atoms convert to metal and as much copper is dissolved into solution to use up any free nitric and replace the silver from solution.

So we can see this is a contact process of electron exchange.

Now lets look at silver plated object to replace our copper, well it may be plated on other metals besides just pure copper, so these may give us problems when dissolving into solution (tin may gel solution, zinc may cement copper with our silver, or any combination of other things we may not want) this has cost us money to get our silver this far, we would not want to contaminate it again,
Also the silver is the surface area, unless we had a lot of free nitric in solution, and added heat the silver nitrate solution would not dissolve this silver metal coating, to get to copper or base metals under the silver plate, so this would either be terribly slow or not workat all process.

Also the silver plate would not give an electron to our silver and cement it.

With this said I see too many troubles with the Idea of using silver plated object to recover silver from the nitrate solution.


I would advise against using this idea, unless less than pure silver is desired and you know how to deal with problems involved.

Use as pure a copper metal source as you can to cement your silver (electrical buss bars), or (clean 6 inch long piece of copper pipe one inch or larger diameter can be cut long wise with tin snips or other saw and flattened out).

If you wanted to try and recover the plated silver from the plated material, I would use the spent copper nitrate from the above reaction, boil your cutup (small pieces) silver plate in this solution to dissolve most of the metals (copper, concentrating the waste materials your dealing with), you can finish up in chloride solution (which will make copper chloride solution and silver chloride), (the HCl acid would regenerate some of the nitrate salts to nitric acid making aqua regia somewhat), but the nitric is more volatile to evaporation than the HCL or chlorides are, so by heating and evaporation, you would end up with copper chlorides green copper II chloride in solution and possibly white powders of copper I chloride mixed with the insoluble silver chlorides, the copper I chlorides can be dissolved away from silver chlorides with warm HCL. (The chloride solution could also be a used acid peroxide solution you wish to concentrate and get some more use out of before disposal).
I use my waste products similar to this, but you also need to know how to deal with other metals in solution when using these solutions for recovery as they can get to be loaded with undesirable metals and then losing values in the recovery process is also greater if you do not recognize them or know how to deal with it.

 

[watcher6880]

Is there a way to test for the zinc or other "undesireable" metals?

 

[watcher6880]

Also I was thinking of doing similar pieces Like the Chippendales and ISC in seperated groups through different refining batches. That way if I happen to have any tin or zinc, it would only be for those seperate batches meaning that I could troubleshoot but if I mixed all of them I would have the beforementioned problem with the various undesireable metals but then again that is where testing should come in.

 

[butcher]

Most of the metals Higher in the reactivity series are difficult to test for in solution, not to say you cannot, but it can get labor and chemically intensive.

Many of these metals can be tested for in solution, but many times it is a process of elimination, can be very chemically intensive of performing many chemical reactions with sometimes very hard to get chemicals, sometimes you may have to remove many of the other metals from solution, and this could be very lab work intensive to find the metal your looking for in solution, sometimes best left to larger labs and chemists.

Some metals are insoluble in certain solutions these are usually easier to identify.

Zinc being very reactive it will even form an hydroxide complexes
Tetra-hydroxo-zincate Zn(OH)4
Zinc will dissolve in most all of the acids.

Zinc will also precipitate many metals lower in the reactivity series than it is, (but you would need to add enough zinc to replace all of these other metals or your solution, or the solution would contain zinc and these other metals in solution).
(Edited to addthis) This solution would also have all of the metals higher in series left in solution which were involved in solution.


A flame test will test for many metals or metal oxides.

Basically yes you can test for zinc in solution, but I do not think by the time you learned how, eliminated the other metals and did all of the reactions needed, found and bought all of the needed chemicals, you would say why go to all of that trouble? That is what I would say.


Chippendales and ISC, I do not know what these are or what it means so I cannot comment.

If you wish to study look for things like:
Reactivity series of metals
Group IIb elements (Zn Cd Hg)
Qualitative analysis
Heavy metals analysis
Ion’s qualitative analysis
Qualitative Analysis of Cations
Isolation of zinc ions in solution.
Or other similar searches, to these.

 

[watcher6880]

International silver co. and I think the chippendales are International Silver as well.

 

[nickvc]

Over the time I have been a member of the forum we have had several people try and recover and refine the silver from plated wares no one seems to have succeeded fully. The main problem been that silver needs nitric to be dissolved and it's expensive and hard to find and also will dissolve the base metal substrate as readily as the silver. One guy I seem to remember was using a medium in a tumbler to remove the silver which seems logical but I'm sure you will remove some base metals or leave a percentage of your silver behind. GSP has mentioned that in the plating industry there is a method that uses cyanide so again most are stumped to source that, perhaps to the good. If the big boys are doing this I'd bet it's either a cyanide process or their shipping the stuff to the copper refiners, the only other cost effective way I can figure is if they are melting the plated ware and then using the bars to cement the silver from nitric dissolutions, saves buying copper and they get the silver recovered for free.

 

[watcher6880]

nickvc-- how about the method described on this site...
http://goarticles.com/article/How-To-Refine-Silver-Using-Household-Chemicals/732873/

 

[nickvc]

Home made nitric isn't the best for silver recovery but should work. The problem with plated wares is that once the base metals are exposed the acid will attack and dissolve them and in preference to the silver and unless you then dissolve all the base metals some of the silver will cement onto the remaining base metals, bear in mind it takes 3 times the acid to dissolve copper as it does silver. If you do one item at a time you could possibly monitor the situation and remove the item from the acid once most of the silver has dissolved but I don't believe you will get all the silver.
If you can get the plated wares for free or very silly cheap and you can make or get nitric acid at reasonable prices and your time doesn't matter then maybe yes this is worth the effort...personally I'd find something easier and with a better earning potential to recover and refine.

 

[NancyH]

Have been researching this forum, and other sources.
Thought I would ask the question...
Have over 100 lbs of HEAVY silver plated items. From OLD military scientific equipment. (Have been successfully recovering the gold, but have LOTS of silver)
Of the over 100lbs over 30 lbs of silver wire. Some is copper coated silver, some is silver alloy.
Question:
Is there a way to recover this silver? It is NOT pure, but I would estimate about 10 lbs of silver (out of over 100 lbs of scrap. The wire alone is probably 30-50% silver)

The process I have been using in recovering the gold is Poormans AR. Had purchased materials from Shor, and found out how to "fix the problems" by reading this forum.
Thanks for the help.

Nancy

 

[nickvc]

Welcome to the forum Nancy.
The first thing you need is a supply of nitric acid and depending on where in the world you are that's not easy for many members, and can be expensive.
I personally would dissolve the silver alloy material first in dilute nitric and use the silver plated copper copper wire to cement your silver out, melted into bars would be better, this means you only use the nitric to dissolve higher % silver and the silver in the copper wire is reclaimed for free.
One of our members was using the AP method on any silver plated copper based material and I think it was working slowly but as the hydrochloric is easier and cheaper to source it makes some sense.
Whatever method you decide to try start small and see if it's cost effective and whether your assumption of silver content is correct as if the silver is very low percentage it won't pay to use the nitric acid.

 

[NancyH]

I am thinking about dissolving it all in Poormans AR.
Drop the silver with baking soda.
Filter. Then drop everything with aluminum.
Wash and dry the metal drops
and then take to a smelter
the smelter creates a "blob" and assays it, then gives me the 85% value of the metals

does this sound feasible?

 

[jimdoc]

Doesn't sound profitable, or fun.

Jim

 

[nickvc]

Doesn't sound profitable, or fun.

Jim

Got to agree with Jim on that.

Nancy to dissolve all that metal is going to take volumes of nitric and bear in mind that silver requires around a third of the nitric to dissolve it than copper does. That was why I suggested trying samples to determine the silver content so you could dissolve the higher content material and use the silver plated copper to cement your silver back out of solution also getting the silver from the plated wire for free.
The balance of the material I would list and sell, here on the forum or on fleabay,if this is a one off job, if it's ongoing the thinner plated material might be worth trying in AP if its copper based, it's slow but cheap and the chemicals are easily available.

 

[NancyH]

I am estimating over 100 troy ounces of silver that will be recovered from 100 lbs. scrap.
Estimate supplies cost around $200
Muriatic Acid and Sodium Nitrate for the Poormans AR

This is ongoing.

I can try the silver wire first. It appears the wire is 30 to 50% silver. It is COATED (insulated) wire.
So the acid will need to dissolve everything, including the copper (but not the plastic insulation on the wire)

I have found someone that will take the other scrap (silver plated brass), melt it and give 85% of value.
Have never used them before and they are not excited about my request to watch the melt.

Once the wire is dissolved I need to drop TWO metals
silver and copper

Has anyone dropped silver using SALT or BAKING SODA?
If so, once I drop the silver...I can drop the copper with the aluminum, correct?

I used aluminum before to drop everything out of a Poormans AR that I was using for gold, because the drop wasn't successful (so I used aluminum and started over)
Then filtered, washed and redid the Poormans AR.
Ended up with over 10 ounces after drying down in a dehydrator.

The material I am working with has between 10 and 100 times the precious metals that are found in computers and cell phones.
It is worth the work.

thanks for the help.
will probably try a small batch of the wire, and let you know what happens

Nancy

 

[nickvc]

Nancy by using salt rather than using the silver plated copper wire you will end up with silver chloride which in quantity is a real pain to rinse well and then you will have to re convert it back to elemental silver, if you use the silver plated copper wire to cement the silver back out of the nitrate solution you get 2 bonuses, elemental silver at 98% and the silver on the copper wire back for free, it's best to melt it into bars if you can as its easier to remove when cementation is complete.

 

[NancyH]

I am sorry, I haven't been clear in explaining.
ALL of the silver wire is COATED with plastic insulation.
Using the wire to cement the silver isn't feasible.

Would a simple clean copper pipe be just as effective?..pounded flat, etc.

And if I use the copper pipe, I assume I would need to neutralize the Poorman's AR first...
dilution with water...or urea?

I know some folks here do not like urea, but it has been successful for me with gold.

and then when the silver is cemented...on to the iron (or aluminum) to remove the copper..yes?

thanks!

 

[Harold_V]

I am thinking about dissolving it all in Poormans AR.
Drop the silver with baking soda.
Filter. Then drop everything with aluminum.
Wash and dry the metal drops
and then take to a smelter
the smelter creates a "blob" and assays it, then gives me the 85% value of the metals

does this sound feasible?

Not in the least. You may be able to dissolve the base metals, and likely will---but you won't dissolve the silver, which is the objective. Unfortunately, it will protect the base metal from dissolution, which is exactly what you don't want. HCl won't dissolve silver to any functional degree. However, if you can get penetration, it's possible that you could dissolve the base metal and leave behind the skins of silver, much the same process as recovering gold from plated pins and fingers. Damaging the plated surface to the point of full penetration would be one way to encourage dissolution of the base metals. The negative aspect is you now don't have base metals (brass and copper) to sell as scrap.

You can strip the silver in a sulfuric cell. Whether you can recover the silver without issue I can not say. I expect it's not a big deal, but don't have any experience to draw from. Bonus---you get the base metals back, ready for sale.

Why doesn't someone give this idea a go? How about processing a few plated forks or spoons, to see how it goes, and if you can recover the resulting silver without issues?

The idea of recovering silver from plated objects wouldn't be an issue if they were all on copper, but they're not. Such objects could be placed in dilute nitric long enough for the majority of the silver to be dissolved, then removed. When the acid showed signs of slowing down, not stripping, the same pieces that were stripped could then be used to cement the silver from the solution. Even if some silver remained, the parent metal would slowly be dissolved by cementation, so in the end you would have used the base metal for recovery, and eliminated all of it without directly dissolving in nitric. Beyond that idea, what Nick said would be worthwhile---where copper was the base metal, not a copper alloy, they could be melted and poured to bars, which, in turn, would be used to cement silver from nitrate solutions.

Harold

 

[NancyH]

Harold,

Getting closer on this, I think.
Using the "dilute nitrate" (I think you mean Poormans AR)
I can dissolve the silver plated copper wire (that is coated with the plastic insulation)

the acid solution is then filtered

and silver cemented with copper

copper dropped (cemented) with iron

....still have the question as to whether I should dilute the acid (with water or urea) before cementing with copper.

If this works, then 30 lbs of the 100 lbs of silver plated scrap is taken care of.

thanks

 

[NancyH]

ooops
misspelling...dilute NITRIC
when I say Poormans, I mean muriatic acid and sodium (or potassium) nitrate