2lb bar of copper gold alloy how to exract?

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thomasfinder

Member
Joined
Aug 20, 2019
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6
Hello I have a 2lb bar which I believe to be ore and low in gold. Is using hydrochloric and bleach gonna work or will it precipitate more then gold since there is copper. Or will it have issues breaking down. I took some and melted it down with borax. End result was a defined gold on bottom and copper on top. Is there a good at home processes at home with the right equipment?
 
I would do a test to see if it actually had gold.
you could file off some shavings and test them, by using nitric acid, cupric chloride or ferric chloride dissolving much of the base metals before dissolving the gold (HCl/ sodium hypochlorite) and testing the solution with stannous chloride...
 
It would not test 10k as a bar. But some melted and borax left separation enough to finally test positive for 10k but wanted to figure out how to dissolve the other metals, without harming the very low karat gold.
 

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Also there is a stamp but cant locate were from. It has been passed down. Won in a card game from a passed relative.
 
I would test the bar first.
Then you can work on a recovery method if it, in fact, does contain gold.

During the test, you can also gain some information that would help in choosing a recovery process, indications of other metals like copper or silver, or tin, and how they may come to play...

Depending on the metal composition, there are several ways you could process the bar, electrolysis, or with acids to dissolve the base metals, depending on the composition the bar, and the process chose the bar may need to be poured into shot, you may have trouble with tin stealing your gold in some processes, or forming metastannic acid in others, or you may find there is not enough gold to cover the cost of the time trouble and acids...

Just a little time testing can save you a lot of time and trouble later.
 
You might want to drill into it first, or even saw it in half. Could be just coated on the outside with low karat gold and the rest is copper or even lead. Would not be the first time that was done.

Drill out about a gram and have a fire assay done on it. That would tell you exactly what you do or don't have. And what you would need to do to refine it.
 
Ya it's not coated but xrf machine showed mainly copper, some zinc, tin and even soil. But 2 % gold. Is this really heard of and why. I know this is about refining but I'm confused on what the application of what this mix alloy was for in the first place now
 
Sounds like you have a faked gold bar as they sell on eBay made from electronic scrap.

The tin would be a big problem in the brass/bronze alloy, making the recovery of that 2% gold very difficult or not cost-effective...
 
I would say your right about the ebay thing but what I do know about it is that it is much older then ebay. And seems a waste to mix gold in that way. I guess ima have to do more research maybe find the stamps origin.
 
I was seeing things like this at least 40 years ago. You still, in all likelihood, have a small bar made of gold plated pins, and probably some bench sweeps from the makers work area.

Time for more coffee.
 
If it was me...

1. test for actual gold content, like all the above recommend.
2. if gold present at a significant level, set up a cheapo copper electrorefining cell (100g/l sulfuric acid, bar in an anode bag and wired as anode, some strip, foil or plate of copper as cathode, a decent power source running maybe 0.5-1 V and probably less than 1 amp) and let it go.
3. eventually, if you keep the voltage low, you will strip away all the copper and the gold and other stuff will be left in the bag.

You will then have a very small amount of material to refine gold from, which can be done by any number of methods, rather than trying to bulk dissolve and then split everything.

Just my random thoughts.
 
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