# Refining gold out of lead tin solder



## Peg leg (Nov 18, 2010)

I was wondering if anyone knew the process for reclaiming the gold out of lead tin solder. I have about three pounds I would like to refine. If anyone knows of a reputable refiner that would handle the lead that would also be helpful. I asked ara and they wouldn't take it. I had a friend who owns a recycling business analyze it for me and his machine said anywhere between 11% and 18 % so it should be worth my time. I saw earlier that someone mentioned the parker process and was wondering if that would work for this small amount of lead as it seems from what I am seeing online that this is more for a higher amount of lead.


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## Peg leg (Nov 18, 2010)

Bassically this is a lead solder pot that has dissolved gold in it.


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## qst42know (Nov 18, 2010)

The Parkes Process:

http://en.wikipedia.org/wiki/Parkes_process

The process calls for the zinc to be vaporized off after the PM's are collected. It would be dangerous to vaporize a quantity of zinc if you weren't set up for it, however it might be possible to digest the zinc in one of the acids.

Anyone here have any Parkes Process experience?


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## goldsilverpro (Nov 19, 2010)

Please don't make duplicate posts. I deleted the other thread.

Here's a post I made awhile back.



> Some of the gold, silver, and copper from the component leads dissolve in the solder, especially if it contains lead. I seem to remember that the limit of contamination for these metals is about 2%, total, before they start getting poor solder joints. The Bureau of Mines once published a Report of Investigation (RI) of stirring aluminum into the molten solder to extract these metals. The Al (containing the Au, Ag, and Cu) floated on top and was skimmed off.
> 
> This is similar to the Parkes process for removing silver (and, gold) from lead. It used zinc instead of aluminum.
> http://www.google.com/search?q=parkes+process&sourceid=navclient-ff&ie=UTF-8&rlz=1B3GGGL_enUS259US259



Unfortunately, I have been unable to get a copy of the RI mentioned above.


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## Oz (Nov 20, 2010)

That is neat GSP, I somehow missed that post. If it is accurate it would be far simpler than the parks process. If you happen to find more details I would be interested.


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## goldsilverpro (Nov 20, 2010)

Oz said:


> That is neat GSP, I somehow missed that post. If it is accurate it would be far simpler than the parks process. If you happen to find more details I would be interested.



I don't remember the details. The material they were working with was 60/40 Sn/Pb from wave soldering machines. As the boards rode over the solder crest, the gold from the leads would dissolve in the solder. 

The US Bureau of Mines published a ton of those Reports of Investigation (RI). Some were mining geological surveys but many were studies of some process (mostly mining related but a few involving scrap) they had come up with. They are hard to find. Here's a place that has a few of them for sale.
http://www.woodenski.com/2neat/usbm/usbmreportsofinvestigations.html

Once I drove to the U of Missouri school of mines in Rolla, where they had a fairly good collection of these. I photocopied a bunch of them but they're long gone now.


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## Gold (Nov 20, 2010)

Here is a list of the publications. I think the one you might be talking about is the one from USBM Information Circular 9059 : 1986 : Precious metals recovery from low-grade resources. Proceedings : Bureau of Mines Open Industry briefing session at the National Western Mining conference, Denver, Colorado, February 12, 1986.
Contents of USBM IC 9059 :
Ion-exchange research in precious metals recovery.
Staged heap leaching – Direct Electrowinning.
Mercury precipitation during cyanide leaching of gold ores.
Carbonaceous gold ores.
Carbon adsorption-Desorption.
Heap Leaching.
The Caron-in-pulp process.
*Precious metals recover from electronic scrap and solder used in electronics.*
I've looked for a copy online but have yet to find one. 
http://www.woodenski.com/2neat/usbm/usb ... ulars.html


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## glondor (Nov 20, 2010)

http://catalogue.nrcan.gc.ca/opac/fr-CA/skin/nrcan-rncan/xml/rdetail.xml?r=7900575&l=123&d=3


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## Peg leg (Nov 22, 2010)

Sorry about the double post gsp. Has anyone used the parkes process? If so does anyone know where to get the zinc?


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## jimdoc (Nov 22, 2010)

http://www.rotometals.com/Zinc-Anodes-Products-s/28.htm


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## Palladium (Nov 22, 2010)

Here is an interesting video i found on wave soldering. 
http://ipc.electronics.ca/DVD-47C.wmv


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## lazersteve (Nov 22, 2010)

Peg leg said:


> Sorry about the double post gsp. Has anyone used the parkes process? If so does anyone know where to get the zinc?



I sell zinc at my website store, see the link below.

Steve


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## qst42know (Dec 10, 2010)

qst42know said:


> The Parkes Process:
> 
> http://en.wikipedia.org/wiki/Parkes_process
> 
> ...



I found a relevant page in the book Manuel just linked to.

http://www.archive.org/stream/appliedelectroch00thomrich#page/66/mode/2up/search/refining+tin

The zinc can be separated electrolytically.


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