Mixed metal bars

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golddigger2

Well-known member
Joined
Sep 25, 2009
Messages
104
Has anyone tried processing mixed metal bars? I have access to an unlimited supply of mixed metal bars containing approx 30% gold, 50% copper,20% silver, nickel, rhodium and tin. I have tried a couple of experiments. using a wedge of mixed metal bar approx 2 inches X 2 inches by 1/2 inch at the fat end down to about 1/8 inch at the thin end. I placed it in A/P solution which appeared to work but was extreamly slow. I may be able to get the bars rolled paper thin which would help with speeding things up. The second approach was using the shor simplicity system and an add on called the nickleodeon. (dont worry i didnt rush out and buy one, I unfortunately purchased it before i found this forum and hardly ever use it) It seemed to work great for the first 24 hours but then the voltage and amperage reduced to zero and i cant seem to rectify the situation. I am emailing shor this afternoon to get some trouble shooting advice. Does anybody have any experience processing these bars? Any ideas?
 
If you have a steady flow of this stuff, why not build a reverberatory furnace and oxidize and slag off the base metals, then you're left with an easy PM mix to clean up.
 
4metals said:
If you have a steady flow of this stuff, why not build a reverberatory furnace and oxidize and slag off the base metals, then you're left with an easy PM mix to clean up.
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I'd give that idea a go long before I tried processing with AR. Between the high silver content and the tin, you'd likely end up with one hell of a mess.

This material is perfect for digestion in nitric, assuming you can allow the nitrate solution to settle, with no filtration (trouble filtering because of tin). I'd cornflake, process with nitric, then incinerate the residues, boil in HCl, then process with AR. With luck, you'd have rhodium as a residue. The incineration and HCl wash would eliminate any problems with filtration. Silver would be recovered with copper.

Harold
 
4metals said:
If you have a steady flow of this stuff, why not build a reverberatory furnace and oxidize and slag off the base metals, then you're left with an easy PM mix to clean up.
Click to expand...

I was going to suggest cupellation. Works even in small batches. Leaves a relatively clean gold, silver, other PM button with only traces of base metals. Make sure you add enough silver so that the resulting button is more than 75% silver so that you can go directly to nitric acid treatment of the shot/cornflaked button.

If the volume is big and you want to recover the copper, nickel, etc. as well, then probably a copper cell and much more ellaborate industrial process will be needed. imo. Out of my league.

IMO direct aqua regia treatment with 20% silver content is a recipe for a lot of frustration and possible disaster.
 
Harold said:
This material is perfect for digestion in nitric, assuming you can allow the nitrate solution to settle, with no filtration (trouble filtering because of tin). I'd cornflake, process with nitric, then incinerate the residues, boil in HCl, then process with AR. With luck, you'd have rhodium as a residue. The incineration and HCl wash would eliminate any problems with filtration. Silver would be recovered with copper.
Click to expand...

Were I to do this, I would do it almost exactly as Harold suggests. The only difference being that, during the melting (cornflaking) stage, I would add enough copper or silver to get the gold percentage down to 25%, or a little less. Assuming you start with 30% gold, I would add 20 grams of copper or silver to each 100 grams of bar weight.
 
golddigger2 said:
Has anyone tried processing mixed metal bars? I have access to an unlimited supply of mixed metal bars containing approx 30% gold, 50% copper,20% silver, nickel, rhodium and tin.
Click to expand...

Mind sharing what these bars where used for, the alloy used in the make up has me puzzled.

Best Regards
Gill
 
The mixed metal bars I am refering to are derived from recycled metal from Computer circuit boards which are reverse electroplated and then granulated and melted. A Friend of mine processes the raw products but doesn't understand the refiners art. I am trying to help him out by finding a way to seperate and refine the gold and recover the other metals as well.
 
golddigger2 said:
The mixed metal bars I am refering to are derived from recycled metal from Computer circuit boards which are reverse electroplated and then granulated and melted. A Friend of mine processes the raw products but doesn't understand the refiners art. I am trying to help him out by finding a way to seperate and refine the gold and recover the other metals as well.
Click to expand...

You may have over estimated your gold content at 30%, have you had these bars assayed.

Best Regards
Gill
 
The mixed metal bars I am refering to are derived from recycled metal from Computer circuit boards which are reverse electroplated and then granulated and melted.
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Although I'm not fond of the term, "reverse electroplated", what method is he using? Sulfuric stripping cell? Or, what?

I would think it would be a lot easier to deal with the sludge or powder and not melt it into bars.
 
I am not sure exactly what his process is as he is understandably very secretive about his process. I do know that it is almost completely chemical free. I do know that it is some sort of electroplating system. The metal comes out of the process in granular form and is melted into bars. As we have only been collaborating together for a couple of months he has not given me the details of the process, as he gets to know me a bit more the flow of information should open up a bit. The main aim is to reclaim the gold and copper initially and then as our experience increases try to reclaim the silver and other metals. My experience is mainly with A/P and A/R but I agreed to do some experiments for him to see if I was able to use a chemical process to seperate and eventually purify the pm's.
 
Given the information that has come forward, it is my opinion that GSP is on the right track. Melting this material is likely a big mistake. There are pretreatments that could eliminate traces of tin, resulting in a very straight forward processing. I can envision a process whereby there would be no melting until the final product has been produced.

If your "friend" is reluctant to share any information, let him tough it out alone. I think I can speak for most readers when I say that we are happy to try to help, but none of us are interested in playing games, especially the guessing game.

Harold
 
Thanks Harold I agree totally. I am sure the information will be forthcoming once he knows me a bit better. He has had a bit of trouble with partnerships in the past and is being a bit overcautious.
 
Just a quick update on how this is going. I was originally trying this in the shor simplicity system which did a pretty good job of deconstructing the bar in to sand like granules. I then evaporated all the liquid off, dried the mixture and incinerated. I have it soaking in nitric as we speak. The next step following Harold's instructions will be to incinerate again and boil in HCL. I will keep you posted.
 
golddigger2 said:
I am not sure exactly what his process is as he is understandably very secretive about his process. I do know that it is almost completely chemical free. I do know that it is some sort of electroplating system. The metal comes out of the process in granular form and is melted into bars. As we have only been collaborating together for a couple of months he has not given me the details of the process, as he gets to know me a bit more the flow of information should open up a bit. The main aim is to reclaim the gold and copper initially and then as our experience increases try to reclaim the silver and other metals. My experience is mainly with A/P and A/R but I agreed to do some experiments for him to see if I was able to use a chemical process to seperate and eventually purify the pm's.
Click to expand...

This granular form you speak off. It makes me think... If its fine enough you may want to tell your associate to leave it in granular form and you may get away with putting it into nitric right away to get the gold out. You should test small batches of course. Test test test.
 

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