# CPU Lids and the gold on the bottom of them



## silversaddle1 (Dec 21, 2021)

I had posted a photo of these lids in a FB group for discussion about recovery and values. Some of them say they have good plating and they are worth refining, some have said not so much. I was wondering what the page here thinks. This tray has 18 pounds in it, and were all knocked off green fiber CPU's with gold pins. I also did a few of the green fiber pinless ones, seems not all have the plating, and the one's that do don't seem to have the surface area as the pinned ones did. I never even knew there was gold under the lid until I knocked a few of the lids off. I was removing the lids to see how hard it was to do since the fiber cpu will sell for more money without the lid.


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## UrbanScrapper (Dec 21, 2021)

I am sure I'll get hammered for this. Test the lid(s) for copper. If they are copper, melt them into a dore bar and refine them in a CuSO4 electrolyte. Then process the slimes for the Au content. Or sand of the gold plating and process that...


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## silversaddle1 (Dec 21, 2021)

UrbanScrapper said:


> I am sure I'll get hammered for this. Test the lid(s) for copper. If they are copper, melt them into a dore bar and refine them in a CuSO4 electrolyte. Then process the slimes for the Au content. Or sand of the gold plating and process that...


The lids are nickel plated copper.


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## Yggdrasil (Dec 21, 2021)

HCl will take the nickel.


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## niks neims (Dec 22, 2021)

My guess is ENIG, 

Easy enough to test - drop one piece in nitric - if the foil stays together (or in flakes at least) it's good thickness, but I'd, bet it will disintegrate in to fine powder...

Also I've heard (here) that clump of solder (connecting crystal to heatsink) is indium...


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## shadybear (Dec 23, 2021)

OK, so you melt the copper ,nickel, Indium and ? into bar, refine through copper cell.
I would have the gold, nickel, Indium in slimes how do you take out the Indium?


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## philddreamer (Dec 23, 2021)

I did a test once, by dropping one in HCl... the nickel was dissolved, and the gold and copper were left.


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## orvi (Dec 23, 2021)

UrbanScrapper said:


> I am sure I'll get hammered for this. Test the lid(s) for copper. If they are copper, melt them into a dore bar and refine them in a CuSO4 electrolyte. Then process the slimes for the Au content. Or sand of the gold plating and process that...


Dissolving will be overkill, i think from first point maybe electrorefining the melted bars in electrolytic cell. Maybe sulfuric cell will do the job in removing just plating better.


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## Martijn (Dec 24, 2021)

A sulphuric stripping cell will leave the copper base untouched. Perfect for cementing in the stockpot after stripping. Or even without stripping should in time leave only the gold foils in the stockpot.


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## speed (Dec 25, 2021)

As mentioned if you run a copper cell they can go through that but it wouldn't be worth setting up a copper cell just for those lids. Theres virtually no gold value in them

I chuck them in my stock pot. Plating comes off then when stock pot gets a clean out they go in the copper scrap.


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## FullGoldCrown (Feb 17, 2022)

I had a happy accident a few weeks back. I wanted to expose the copper under the aluminum coating. I put them in an 1:1 AP solution of 35% acetic acid, 3% H2O2 with a splash of sulfuric acid (10 to 15 mL) in a beaker. I then placed the beaker in water in a cock pot on high--after about a week the gold came off the heat sinks and the silica processor. Try it out tell me what you think.


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## patnor1011 (Feb 17, 2022)

Thiourea cell work fast on this plating. Is it worth it? Depends on how much time do you have. I have no doubt you can scale it I just did little experiment to see it working. Perhaps placing anode and cathode horizontally and not vertically may speed things up a little too.


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## FullGoldCrown (Feb 17, 2022)

Personally, sulfuric acid scares the s--- out of me, peracetic acid is pretty safe. Like a previous thread said: do a trial of 10 heat sinks each. Have fun, be safe. I like your ambition. Never have done a cell...yet. Good luck.


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## macfixer01 (Mar 4, 2022)

silversaddle1 said:


> I had posted a photo of these lids in a FB group for discussion about recovery and values. Some of them say they have good plating and they are worth refining, some have said not so much. I was wondering what the page here thinks. This tray has 18 pounds in it, and were all knocked off green fiber CPU's with gold pins. I also did a few of the green fiber pinless ones, seems not all have the plating, and the one's that do don't seem to have the surface area as the pinned ones did. I never even knew there was gold under the lid until I knocked a few of the lids off. I was removing the lids to see how hard it was to do since the fiber cpu will sell for more money without the lid.



Aren’t you going to scrape that soft indium metal off those and collect it? I believe I read a couple months ago that Exotech is buying it now?


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