# Gold Plated Sterling Coins



## goldmelts (Jul 3, 2008)

HI,

Would it be feasible to dip Gold Plated Sterling Coins in HCL-CL solution, to remove the gold plating? This will surly remove some of the silver and copper in the sterling.

The precipitated can then be refined again to get pure gold/ silver. Any thoughts?

Can the above process be used to do bulk recovery, with the intention of later refinement of the precipitate? You can use anything gold plated (ie. plated jewelery, electronics, etc.) to recover the bulk of the gold, then refine later for purity.

goldmelts


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## SilverNitrate (Jul 4, 2008)

I do this all the time, as I use the silver for silver containing products. Gold plated sterling esp. the Franklin Mint stuff tend to have a really small amount of recoverable gold. usually 3 grams to 100oz sometimes less. If all you want is the gold off the silver, HCl-H2O2 and perhaps a tiny HNO3 similar to working the fingers, process. 
Tho you will have some rather gunky silver coins unless you dissolve all the way.


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## goldmelts (Jul 5, 2008)

my objective it to remove the gold plating, then send the sterling to large refiner for purification. I probably have over 100oz of gold plated sterling coins, so three grams is good.

I just don't want to send the whole lot to a refiner, and let them keep the gold. I'm sure they won't tell you how much gold was recovered, just keep it themselves.

I was thinking to mix a batch of HCL-CL, throw all the medals in, then fish them out when no gold plating is visible on the medals. Does this sound like a plan?


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## goldmelts (Jul 5, 2008)

So your saying H202 not CL?

HCL-H202 then refine plating with HCL-CL.

What about straight HCL-CL to disolved the gold plating straight away?

Which is the best method to avoid copper/silver being dissolved with the gold plating?


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## SilverNitrate (Jul 5, 2008)

I haven't tried any method besides dissolving them in nitric. this leaves behind the goil, and the characteristic green silver nitrate.
http://goldrefiningforum.com/phpBB3/viewtopic.php?t=2091
Using AR to dissolve the gold off will work, but the silver will do a job on the nitric once its exposed. 
another method may be NaCl(aq), H2SO4 & H2O2 to make the gold peel off (and dissolve)


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## goldmelts (Jul 13, 2008)

Hi,

What about the below procedure:

1. dip coins in HCL+CL until gold is dissolved. This will leave a dirty gold solution (some silver and copper in it).
2. precipitate the gold with SMB, again this will leave a dirty gold precipitate.
3. wash the precipitate with ammonia to remove the silver.
4. wash with hot HCL to remove any base metals.

I'm assuming this will leave pretty pure precipitate, what are other opinions regarding the above process.


Goldmelts


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## goldmelts (Jul 15, 2008)

Ok, after some reading on the forum:

Quote:
"If it is silver chloride you can simply dissolve the gold foils with HCl-Cl and it should leave the silver chloride behind. 

Diluting the resulting auric chloride solution with a little water should remove any silver chloride that was carried over with the strong acid in the HCl-Cl"


So there is no need for a ammonia wash to remove the silver? therefore, missing point three below. Does this seem right? The question is, is silver in solution silver chloride?

goldmelts


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## lazersteve (Jul 15, 2008)

There are no shortcuts to high purity gold. 

Silver chloride and copper compounds are very hard to eliminate completely from gold. Partly due to the slight solubilities of the compounds in acid medium and partly due to drag down when precipitating. By swinging the pH basic with ammonium hydroxide you can remove the final traces of silver chloride (which is soluble in ammonium hydroxide) that may have tagged along with any residual acid in the gold powder. Copper is also soluble in ammonium hydroxide as well as some other base metal compounds.

There's an old saying an ounce of prevention is worth a pound of cure. It's much easier to clean traces of silver chloride out of the gold powder with a quick hot ammonium hydroxide wash than it is to remove the resulting metallic silver from the melted button. In the long run the small amount of extra effort spent in the wash stage is well worth the purity you will see in the final product.

Steve


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## goldmelts (Oct 1, 2008)

HI all,

I'm getting all the things together for try to remove the gold plating.

I have over 100 gold plated coins each about 2 inches diameter.

I initially wanted to dip the coins individually in HCL-CL but his would take a log time.

Do you think it would be feasible to throw all coins in a container then add HCl-Cl then decant the solution when the gold plating seem to have dissolved?

OR

Go the AP route and collect the gold flakes after the AP dissolves a small amount of sterling (silver / copper) under the gold plating

Can AP dissolved the sterling under the gold plating enough for it to detach?

thanks,

Goldmelts


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## lazersteve (Oct 1, 2008)

I would process them with the sulfuric electrolytic cell.

Steve


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## goldmelts (Oct 1, 2008)

HI Steve,

Yes I was thinking that the cell would be the best way. I'm setting myself for APing some fingers, and don't have all the items needed for the cell.

Do you have any input to the AP of HCL-CL process on these coins?

Thank you.


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## goldmelts (Apr 1, 2009)

HI all,

Haven't had time to post on the forum lately. Have been busy, hope everyone is well.

Does anyone have additional input to the Sterling coins in HCL-CL?

I forgot to add I am in a country were there is no access to common refining chemical, so will have to stick to common household items.

I though about another way.
1. Get some plastic tongs thay will hold the coins.
2. make a solution of HCL-CL
3. dip the coins and agitate until gold plating is removed.
4. dump processed coins in water to wash the HCL-CL

Any thoughts?? I have attached a photo of what the coins look like.


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## nickvc (Sep 21, 2009)

personally i would cyanide strip the coins/medals and recover the gold from the solution if your allowed to do this, it is slower but its easier to see when the golds all off if you do them in batches in a basket of some type, heating the solution makes it quicker and a wash after stripping leaves the coins easily tradeable. Add the rinse water to your solution as this will contain gold traces. Some silver will go into solution but in my opinion too little to matter, but it is recoverable.


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## Fournines (Sep 21, 2009)

Had a client once who brought in 158 troy oz of sterling silver coins plated with gold. Each coin had about the same surface area as an American Silver Eagle.

The silver assay was 92.54%
The gold assay was 0.045% or 0.07 troy oz (2.177g) of fine gold.


Something to consider is the plating, is it 24k, or 18k, or less?


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## lazersteve (Sep 21, 2009)

If chemicals are a problem for you, the salt stripping cell is a very easy way to remove thin layers of gold. The silver will form a layer of silver chloride and passivate after the gold is removed. 

Salt Cell

Steve


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## grainsofgold (Oct 3, 2009)

Why not just use it to inquart gold and recover the silver and the gold as usual?


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## goldsilverpro (Oct 3, 2009)

Most decorative plating, whether 14K, 18K, or 22K is, in reality, very close to 24K. The karat designation is actually the color and not the gold percentage. Unlike cast gold, when plated, it takes very little base metals to alter the color - don't ask me why. 14K and 18K color golds are actually around 22K+ to 23K+, in gold concentration.


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