Recovery from Gold-Filled with CuCl2?

[bhilton]

Hi All,

I am not in a hurry and I was wondering what pros/cons there might be for recovering gold from gold-filled with CuCl2.

I am thinking I could snip a bunch of gold-filled jewelry into smaller pieces and let it bubble in some CuCl2 for a week or more?

I'll check it daily and if notice some salts forming on the bottom, the HCL is likely saturated, so I will let it settle, decant 3/4 of the solution and top it up with fresh HCL (and repeat as much as I need to).

Would there be any downfalls to this solution, comparing it to the common method of using Nitric acid boils?

Any pitfalls I could run into?

I have 223 grams of gold filled from a jeweler to practice with right now. He has another 3 kg of material that I can process later, but I want to see how I am able to handle this first batch of 223g.


Thanks,
Bill

 

[Shark]

It will work fine, although it may take more than a week to process it. In one liter of CuCl2 it took me 5 days to strip one pair of eyeglass frames. I was running a lot of air through it and it was very aggressive bubbles. You need an excessive amount of copper chloride and plenty of air, but it also doesn't need to get to cold.

 

[Shark]

Day 5 of the eyeglass frames. I processed the gold in day 6.

 

[bhilton]

It will work fine, although it may take more than a week to process it. In one liter of CuCl2 it took me 5 days to strip one pair of eyeglass frames. I was running a lot of air through it and it was very aggressive bubbles. You need an excessive amount of copper chloride and plenty of air, but it also doesn't need to get to cold.

What do you mean "it also doesn't need to get to cold" ?

 

[Shark]

If you process outside, in cold weather it will take longer to strip the base metals.

 

[bhilton]

If you process outside, in cold weather it will take longer to strip the base metals.

Ok, that's what I thought, thanks for clarifying!

Now some of this jewelry has no GF or 1/20 markings on it.

What is the simplest way to test it? I don't have an acid test kit, but I do have HCL and Nitric acid.

Maybe I can file some of the unknown pieces into a dropper dish and drop hcl+nitric in it and then stannous test it, does that work for small amounts of filings?

 

[Shark]

Ok, that's what I thought, thanks for clarifying!

Now some of this jewelry has no GF or 1/20 markings on it.

What is the simplest way to test it? I don't have an acid test kit, but I do have HCL and Nitric acid.

Maybe I can file some of the unknown pieces into a dropper dish and drop hcl+nitric in it and then stannous test it, does that work for small amounts of filings?

It will tell if it has gold in solution, but it won't tell you if it is gold filled or just plated. You might file a notch in it and add a drop of nitric on it. If it copper based it should give a off color. The color will depend mainly on what the base metal is. Karat gold should remain clear.

 

[bhilton]

It will tell if it has gold in solution, but it won't tell you if it is gold filled or just plated. You might file a notch in it and add a drop of nitric on it. If it copper based it should give a off color. The color will depend mainly on what the base metal is. Karat gold should remain clear.

Since I am not buying the material, I am only looking to validate the presence of gold before I recover it.

The gold plated would still be just fine in the cucl2 bubbler, right? Or would you do gold plated differently?

Once I'm done, I take a % of gold recovered, factoring in my costs and time.

 

[Shark]

Gold plated I normally use a sulfuric stripping cell for volume. If it was only a few pieces it could go into CuCl2.

 

[goldscraphobby]

Ok, that's what I thought, thanks for clarifying!

Now some of this jewelry has no GF or 1/20 markings on it.

What is the simplest way to test it? I don't have an acid test kit, but I do have HCL and Nitric acid.

Maybe I can file some of the unknown pieces into a dropper dish and drop hcl+nitric in it and then stannous test it, does that work for small amounts of filings?

Get a test kit, don't bother with GP - not worth the time & waste. if you are doing this as a test do only the marked material or if you tested it. A drop of test acid on gold filled will not react for some time. Gold plate will react quickly, if it's HGE or RGP it will hold longer and can be worth the time

 

[TBoom27]

Generally with gold plated, a drop of test acid on the piece will bubble right away, or after a few seconds, if it’s heavy plating. Gold filled, if a drop is placed on a spot without excess wear, the acid will not react at all, the gold on Gold Filled is thick enough to prevent the acid from getting to base metals.

 

[bhilton]

Generally with gold plated, a drop of test acid on the piece will bubble right away, or after a few seconds, if it’s heavy plating. Gold filled, if a drop is placed on a spot without excess wear, the acid will not react at all, the gold on Gold Filled is thick enough to prevent the acid from getting to base metals.

A drop of nitric acid? Dilute nitric? Or only use a test kit? Which I don’t have.

 

[Shark]

Just nitric, the color change on the base metal is all your looking for. I never diluted it, but I got test acids pretty quick and have kept them on hand ever since.

 

[TBoom27]

Nitric or a test kit works, but mostly I use the test kit it on unmarked pieces I suspect are Karat vs gold filled, which requires another couple of steps to confirm solid gold and what Karat if any. When testing, be sure to have good ventilation, plated pieces can react fast and with nice little whiffs of pretty red fumes.

 

[kurtak]

I am thinking I could snip a bunch of gold-filled jewelry into smaller pieces and let it bubble in some CuCl2 for a week or more?

If it is GF jewelry you need to be aware that "some" GF jewelry can have the gold over silver

in other words instead of the gold being over a base metal it can be over silver & in that case the CuCl2 method will not work well

So you need to check each piece of GF to see if it is GF over base metal or GF over silver

If it is GF over silver you are MUCH better served processing that with nitric

When I was processing 1 - 3 kilo batches of GF jewelry they could run anywhere from 10 - 30 % GF over silver

Kurt

 

[Shark]

Kurt is right about the silver. Usually called vermeil, it is gold over silver. I often forget that as I try to separate them as two different materials. The down side is that not all vermeil is marked.

 

[bhilton]

Thanks everyone!

I just placed a drop of nitric on one of the unmarked pieces and within 60 seconds it started fizzing and turning aqua green. I'm guessing gold plated or not gold at all.

I tried a drop on a marked piece G.F. and it after 10 minutes there was no reaction at all.

 

[bhilton]

Update, I noticed some watch pieces the outside has no reaction with nitric but the inside does react.

Is this considered gold- filled? or whatever it might be called, is it worth processing more than gold-plated?