Gold trapped in solution

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Rreyes097

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My material is gold filled jewelry and watches and such. I tried to follow the instructions to the t, but now my solution won't give up is gold, I messed up I think and put the rest of the solid material that wouldn't desolve in my stock pot, which is also another problem. That the problem I think is that I put far too much cooper in. So im not sure where to start. Any tips are helpful
 
In my very limited experience, the only time my gold got 'stuck' in solution was when there was still nitric acid in solution. How did you remove the excess nitric ? I assume we are talking about regular recovery/refining here, and not a Sulphuric Cell or other gold leach ?

If you have far too much copper in there, your AR will have a green color instead of the normal deep yellow, but that hasn't prevented me from dropping the gold (and ending with a blue color).

If you did put a lot of copper into the AR, that would have consumed the excess nitric, but when you drop the gold, you will have it mixed with the left-over copper. There should also not really be much copper that comes out of your stock pot (unless you use copper powder in your stock pot to drop the PMs) ?

A few more details and a few more pictures would help a lot.
 
It would help if you clarified your situation a bit. What was your process with the gold-filled material? And do you mean that there's too much copper in your final AR solution, or in your stockpot?

Göran's question about stannous testing is key--you need to know if there actually is any gold in your AR or not. If that's where you added "too much" copper, then yes, you may have nothing but copper in your solution, and what went to your stockpot is both leftover copper and all your PMs. That's not a problem, per se, because now at least you know where it is, and it won't go anywhere if you leave it alone.

If you were worried about copper in your stockpot, while there are always extremes, it's pretty difficult to have too much copper there--an excess of copper is what cements your PMs out of solution. As long as the stockpot solution is fully saturated with copper (or other, more reactive, metals), there's no room in it for gold, silver, etc. If that's not clear, read up on the reactivity series of metals--it's much of what our acid work, particularly dissolution and waste processing, depends on.
 
So to clarify a couple of things. Stannous test showed nothing. I put too much copper in the stock pot not in the AR. I used aqua regia to get the gold disolved. I used the Gold filled method that I seen on gold refining forum. Incinerate next nitric acid diluted I followed everything I could to the letter except sifting it through a screen.) putting urea into the solution there was no bubbling when putting SMB into it there was no reaction whatsoever. I am adding a picture of the Stannous test and of my solution the color is a deep green. I put the solids that didn't dissolve in the nitric acid I put that into my stock pot which I think has too much copper but that's a different subject that I shouldn't have put on to this post. Please help
 

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Are you saying you tried to dissolve all the base metal with gold plating in AR ? Why did you put the undissolved stuff in the stock pot ? There can't really be too much copper in a stock pot, it's only function there is to cement out precious metals.

Do you have any known gold solution so you can check your SC ?

If it were me, I would get some flat, clean copper sheet and put it in that green solution, it will do 2 things - Kill any excess nitric and cement out any precious metals in your solution as black powder (give it a few days).
 
Rreyes097 said:
I used aqua regia to get the gold disolved. I used the Gold filled method that I seen on gold refining forum. Incinerate next nitric acid diluted I followed everything I could to the letter except sifting it through a screen.) putting urea into the solution there was no bubbling when putting SMB into it there was no reaction whatsoever.

So, did you allow nitric to digest everything it could before adding AR? If so, you should only have gold (and possibly other PMs other than silver) for the AR to digest. If you simply put in nitric once, but didn't decant that solution (presumably pregnant with base metals), test that solution for gold, then also add more nitric to your material, you still had undissolved base metals.

For example, say you have a amount of base metal that will take 2 liters of nitric to digest (plus the gold content). If you only put in one liter of nitric, with whatever amount of dilution, decant that liter back off, then add AR (say, 500mL) to leftover solids, your AR is now dissolving more reactive basemetals first, not gold. If you took all leftover undissolved material and put it in your stockpot, that's where your gold went.

Color is a clue, but only a clue--green can be yellow (gold) + blue (copper), but it could also be nickel.
 
If your stannous test is negative it either means there is no gold, or the stannous have gone bad. To test your stannous you need a test solution with known gold content. That should give a positive test or the stannous is bad.

As upcyclist wrote, it sounds like your gold went into the stock pot.

Göran
 
g_axelsson said:
If your stannous test is negative it either means there is no gold, or the stannous have gone bad.
One other possibility is if there is still a lot of oxidizer present in the solution. As quickly as the gold is reduced by the stannous, it is redissolved, resulting in a negative test.

Dave
 

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