# Need help with CPU on boards.



## Makcc (Jun 11, 2020)

Hello everyone.
Thank you for all the information that has been so generously and selflessly shared. 
I am planning to process some CPUs and even though I am new to the forum, I am not new to gold recovery. 
I have a quantity of CPUs that are soldered on circuit boards and the boards have been cut quite close to the CPU. This makes removal with a heat gun impossible. 
Please suggest a method on how to deal with these CPUs ;that is how to separate them from the boards and solder or any other advice on how to proceed to recovery.
I am attaching pictures of samples of the said CPUs. Please disregard the background.
Thank you.


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## glorycloud (Jun 11, 2020)

Yeah, that's not fun to do but it can be done. You can heat the board side with
a heat gun and the solder that holds the pins from the CPU on the board will
melt allowing you to pry the board away from the CPU. Just watch the solder holes
and you will see when they become "shiny" meaning the solder is probably molten.

I have done it dozens of times so I know that it can be done with a good heat gun. 8)


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## Aristo (Jun 11, 2020)

I have some but its quite difficult. The bent legs presents a problem after the solder melts.
Perhaps Incineration in a controlled environment if the quantity is significant.


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## denim (Jun 11, 2020)

These boards might be worth more to a collector than the value of the precious metals contained in them. They are beautiful boards.


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## Makcc (Jun 11, 2020)

Thanks.
Yes, the bent legs are troublesome but I will keep trying. 
Any chance soaking in HCl might be effective?
Denim, I have about 40 of those boards and several others that I plan to depopulate. 
see attached.


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## kurtak (Jun 12, 2020)

Concerning the "three" CPUs at the bottom of the first pic of the first post (the one where the CPUs were "cut" from the circuit board) - YES - I would just put them in HCL to dissolve the solder away which should allow you to separate the CPUs from the cut off CB (you need to get rid of the tin/solder anyway at some point - so do it now) 

Concerning the "complete" CBs - there are several ways to deal with depopulating them - however I don't have time to go into all of that right now

Those are some VERY nice CBs & with 40 of them should be a "nice" payday

As Denim pointed out - they "may be" worth "more" as is - MUCH more if you can find a market for them "as is"

Kurt


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## Makcc (Jun 12, 2020)

Thank you. 
Is it better to use diluted HCl or just plain muriatic acid?
I checked and there's about 32 lbs of the cut off CPUs. Most of them have non magnetic capacitors on the back of the piece of board.. Or what appears to be cap.


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## jarlowski1 (Jun 12, 2020)

Try to get the mlcc (capacitors) off the cpus/boards before you put them in the Hcl and save them as I suspect all or most on those boards will be non magnetic. The Hcl you just use it full strength there is no need to dilute it.


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## Makcc (Jun 13, 2020)

Thank you.
I will lift the caps with the heat gun and let the CPUs soak in HCl.. 
Unrelated... I saw this on ebay. 

https://www.ebay.com/itm/293606249778


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## kurtak (Jun 13, 2020)

Makcc said:


> Thank you.
> I will lift the caps with the heat gun



You don't need to do that - just put them (the "cut off" CPUs/boards) in "full strength" HCl (do NOT heat) the HCl will dissolve the tin - getting rid of the tin - in the beginning of the process is the "first" thing you want to do - including getting rid of the tin that has the ceramic caps soldered to the board

In other words - if you use a heat gun to depopulate the ceramic caps from the board - you will still have to put them in HCl to get rid of the tin before processing them for the Pd/Ag - IF (big if) they are the non magnetic Pd/Ag type caps

Put the CPUs (with the cut off boards) in a 5 gallon bucket - cover them with HCl - let them soak for 20 minutes to a half hour - pick the bucket up by the handle - while holding the handle use a back & forth "twisting" action (be aggressive) so that fresh acid gets to all parts &/or in between the boards/CPUs --- this part of the process will take "about" 3 - 4 hours --- I usually just let it go for a day while doing other things & just go twist the bucket every once in a while - in other words I don't time it I just go do it every so often while doing other things

Next day I go & pour the acid off & then wash the acid out using the same twisting method - takes several washes to get all the acid out 

When done with the washes most if not all the ceramic caps will have come off the boards from the twisting action durring the process & you can then separate the CPUs from the boards - may have to pry them apart due to bent pins but they will come apart without much problem

Because you got rid of the tin "first" in this process - you can now go for the gold without worry of a stannic tin problem when you move forward (or at least "much less" of a stannic tin problem)

Concerning depopulating the other boards you have three options - you can do an HCl soak - or use heat with ether a heat gun or by setting them on a hot plate - or knock them off with a chisel

Personally I "prefer" knocking them of with a chisel & a hammer --- the chisel I use is called a masonry de-scaling chisel like the one in the link

I will explain the up side & down side to each of these methods later & why I prefer the hammer/chisel method

Concerning expected yield from those boards - there is no why to tell because some of the boards are "loaded" with the ceramic chips - while some of the boards have fewer of the ceramic chips --- so the real question is how many ceramic chips you end up with "after" depopulating the boards

As a WILD guess --- at least 1 ozt - & "maybe" as high as 2 ozt

Link to pic of chisel I use :arrow: https://www.bing.com/images/search?view=detailV2&ccid=0%2bpEAQrl&id=1D7C5CD0052DCD642E2843F903BD953816F8B3FD&thid=OIP.0-pEAQrlvMG1R0JwL8fOGgHaFx&mediaurl=http%3a%2f%2f1.bp.blogspot.com%2f-JSlCyzLXqEk%2fVGefK1oV7-I%2fAAAAAAAAB88%2fOZn6CSP9TxY%2fs1600%2fJ.%252BTyzack%252B%2526%252BSon%252B4.5%252Binch%252BBolster%252BChisel.JPG&exph=1001&expw=1283&q=concrete+chisel+types&simid=608040860706146790&ck=0D1F170556351D345A9600DC3242EED2&selectedIndex=28

Kurt


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## Makcc (Jun 13, 2020)

Outstanding Kurtak. 
Thanks for the added details. 
Hmm.. 2 ozt... I can get new shoes.


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## etack (Jun 16, 2020)

really all you meed is to put them in an oven for a few minutes and the chips will come off real nice. Heat gun on a stand with some long hemos will work too. 

The boards I had like that the PBC was glues to the/a metal. The heat gun was easier than removing the board.




Eric


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## Makcc (Jun 28, 2020)

Update :

35 lbs of mostly SUN CPUs soldered on board placed in bucket of muriatic acid until fully submerged.
One week.. swishing the bucket once daily. 
Result:
Blackish goo found on side and bottom of bucket. CPUs still holding strong on the circuit boards.
Muriatic acid is distinctly purple (definitely nano gold).
Tops of CPUs have lost the gold plating.

I would not recommend this method to remove CPUs from circuit boards. So far it's ineffective and gold may be lost.


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## FrugalRefiner (Jun 28, 2020)

Your gold is not lost unless you throw it away. Even colloidal gold can be recovered.

Dave


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## etack (Jun 29, 2020)

Makcc said:


> Update :
> 
> 35 lbs of mostly SUN CPUs soldered on board placed in bucket of muriatic acid until fully submerged.
> One week.. swishing the bucket once daily.
> ...


LOL its like you made a bunch of Stannous then used it.

GSP compared nano gold to "smoke or gelatin" advocated to dissolve again (H2O2 or bleach would work) then to precipitate.I would try to heat the liquid to get rid of a lot of the water first it will stick to everything, but just wash you utensils in the solution it will clean the gold up.

Eric


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## Indigo Suelo (Apr 22, 2021)

Make, my suggestion to you is treat as a leaching process. This will maximize your yield and produce a cleaner product. 
Heat is used but not a heat gun. In fact a low heat on stove top to simmer the acidic solution and bring to optimal temp for the acid to work. 
I'd you are unfamiliar with the leaching process pm me and I'll walk you through it.


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## Geo (Apr 23, 2021)

Did you remove the boards from the aluminum brackets before you put them in HCl?


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## snoman701 (Apr 23, 2021)

Putting the whole board in acid is foolish. As is putting a bunch of processors into HCl without pre-treating. 

The proper method of treating this waste with hydrometallurgical methods is well defined on this board elsewhere. You break each ceramic processor, do a short soak in warm nitric to free the silicon dies, pins and caps. Decant, saving leach. Leach will have Ag/Pd. Just save it. 

I personally prefer to remove large portions of ceramic and process them separately (first). The pins and caps are put in a second beaker. 

Now add HCl and warm to 90 deg C. Add nitric in steps until no more reaction occurs. This won't take long. You may still have enough residual nitric from the first wash to get it done. 

I then decant off the pregnant leach on to the beaker with lids and pins and small crumbs of alumina which I dissolve last. 

I do this for a couple reasons. The longer you boil the ceramic in pregnant leach, the more gold you temporarily lose. The alumina will soak up a significant amount of gold. The second reason is I can do a quick hot wash of the alumina ceramic bodies, then just add the wash to my leach. Usually I end up having to add a little more HCl because dissolving the caps takes so much HCl.


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## Indigo Suelo (Apr 28, 2021)

To specify, CPU boards and computer scrap contains a low yield per piece being recycled. Something like 3-7 grams per Computer tower.(pending brand name and age of device) $$(some brand contain more (HP) and some less (e-machines)
Personally I don't waste time on that, to much of it needed to be profitable, unless you have a supplier of bulk material. 
The process and method I had suggested was how I first learned. It is an effective way to separate and identify the precious metals in their raw form. 
Personally , I extract from natural finds in rural locations , tons of fun. 8) 
Now it has been a while since doing a recycle process, but I would have to agree with you on the separation of the components, I figure thaT common sense, if you don't separate your components then you could compromise your find, for semi precious metals like silver or copper, and let's be honest if you are looking to turn a profit then you would want the least amount of waste. 
Aside from that the leaching process is a very effective method for extracting precious metals from electronic scrap. As well as natural finds. 
Thank you for your response, and do view my other posts. 
If you are interested in a natural find d excursion onbox me and I could give a couple suggestions.


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## g_axelsson (Apr 30, 2021)

Indigo Suelo said:


> To specify, CPU boards and computer scrap contains a low yield per piece being recycled. Something like 3-7 grams per Computer tower.(pending brand name and age of device) $$(some brand contain more (HP) and some less (e-machines)
> Personally I don't waste time on that, to much of it needed to be profitable, unless you have a supplier of bulk material.
> The process and method I had suggested was how I first learned. It is an effective way to separate and identify the precious metals in their raw form.
> Personally , I extract from natural finds in rural locations , tons of fun. 8)
> ...



3-7 grams of gold per computer tower? In your dreams. Maybe in bigger main frames from 1980 or specialized huge server machines only found in data centers, but ordinary tower machines, never.

Göran


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## Indigo Suelo (Apr 30, 2021)

Well goran,
If you would read what was stated you would have known that I stated ,pending brand and age of devices. 
For example older Macintosh boards are heavy plated where as new e-machines are not. 
If you recycled these products and are not getting T least several grams per unit recycled, then check your technique and be more careful in your rinse process.
Note you don't have to take my word for it, you can contact the companies themselves and have them tell you exactly . Also to be noted that is how I know. 
Again thank you for reading the post I hope you found it informative and do read my other posts on varing topics.


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## jimdoc (Apr 30, 2021)

Indigo Suelo said:


> Well goran,
> If you would read what was stated you would have known that I stated ,pending brand and age of devices.
> For example older Macintosh boards are heavy plated where as new e-machines are not.
> If you recycled these products and are not getting T least several grams per unit recycled, then check your technique and be more careful in your rinse process.
> ...



You sure do come off as an expert. Can you let us know how you became such an expert?


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## etack (May 1, 2021)

jimdoc said:


> Indigo Suelo said:
> 
> 
> > Well goran,
> ...



I think I know and feel this person. Hot and ready to go. Deep breaths and knowing the ropes and plenty of smiles.

Eric


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## g_axelsson (May 1, 2021)

Indigo Suelo said:


> Well goran,
> If you would read what was stated you would have known that I stated ,pending brand and age of devices.
> For example older Macintosh boards are heavy plated where as new e-machines are not.
> If you recycled these products and are not getting T least several grams per unit recycled, then check your technique and be more careful in your rinse process.
> ...



Let's see... Power Mac 7500/100, old enough? Not a lot of gold there.


Mostly connectors with partially plated pins and some chips with bond wires. Not a lot of gold there. If you are lucky you could have about a kilo of circuit boards here.
I just sold this computer for about the same price as 1 gram of gold, no refining needed. I don't think I made a bad deal.

ND-5000 mainframe CPU. 


About 3,5 kg pure art. :mrgreen: 
Three layers of circuit boards stacked with gold plated connectors. Custom ASIC in purple ceramic...

The CPU belongs to the ND5000 line of mainframes. The larger cabinets can take four CPU:s but these two cabinets only have two CPU:s each at the moment.


Two computers and one disk storage cabinet. No, it's not for refining, it's for my classic computer collection. I got it this autumn. Five pallets, two computers with a shared file store cabinet and two pallets with circuit boards, documentation and other spares.
This is the kind of mainframe that could yield several grams of gold per computer if you would extract it.

So... what model of Mac or HP would give more than 5 grams? Please share. :wink: 
I have a bunch of HP servers and Macintosh computers in my house. I also have a couple of IBM e-machines.

Göran


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## Indigo Suelo (May 11, 2021)

Thanks but no thanks, I learned on a computer, but I do natural extractions of precious metals and ores now. 
It does look like you have a considerable amount of material to recycle, my best advice for you is go slow and rinse and neutralize often. 

Your yields will vary pending brand name. 
And the seemingly sny comment made by Jacob... My response is, read the post I stated how and where the information comes from. My expertise comes from actual experience. 

At this time I would like to simply say, this is not facebook, I'm not looking for halfwits to randomly attack iteligent responses. If you are seeking assistance and I can lend a hand ask, but if youre some halfwit looking to frustrate or irratate persons posting... Do everybody a favor and grow up. Thanks have a nice day.


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## FrugalRefiner (May 11, 2021)

Indigo Suelo, you're a new member. We don't have any idea whether you are an expert or not.

If you continue to insult members by referring to them as " halfwits", your stay here will be brief. See the foum rules at Board Policy-------This should be read by everyone.

Dave


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## Yggdrasil (May 11, 2021)

Indigo.
Maybe just maybe, you should take your own advice.


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## Makcc (May 11, 2021)

snoman701 said:


> Putting the whole board in acid is foolish. As is putting a bunch of processors into HCl without pre-treating.
> 
> The proper method of treating this waste with hydrometallurgical methods is well defined on this board elsewhere. You break each ceramic processor, do a short soak in warm nitric to free the silicon dies, pins and caps. Decant, saving leach. Leach will have Ag/Pd. Just save it.
> 
> ...



Let me clarify that i was talking about the SUN CPUs at the bottom of the pictures and not the entire boards....please read my original post.
Member Kurtak had provided a solution.
I believe that this thread has deviated and no longer serves a useful purpose so if the moderators want to close it before it becomes a source of issue, thats fine.


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## stella polaris (May 11, 2021)

@Göran or other that knows.

The female connectors (contacts) on the 3,5 kg pure scrapping porno photo. Any idea of the yield of that type pinns? 

Have a bunch of them if the same. Mine only have pins in the outer rows. The middle row is empty. Only pins in every second hole. Looks good even if not fully plated. Easy to pull. Or is it just to put in pyrolysis together with lower grade?


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## g_axelsson (May 12, 2021)

stella polaris said:


> @Göran or other that knows.
> 
> The female connectors (contacts) on the 3,5 kg pure scrapping porno photo. Any idea of the yield of that type pinns?
> 
> Have a bunch of them if the same. Mine only have pins in the outer rows. The middle row is empty. Only pins in every second hole. Looks good even if not fully plated. Easy to pull. Or is it just to put in pyrolysis together with lower grade?


There are no solid yield numbers of those connectors. That type has been manufactured for over 40 years at least and by many companies. Older connectors, especially wire wrap models, could contain up to 10-15 grams of gold per kilo, but then we are talking about thick fully plated pins. Later on the manufacturers became very good at just partially plate the pins so there are less gold per pin. Some cheaper ones are only gold flash.

Göran


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## Indigo Suelo (May 13, 2021)

That is accurate , companies these days find it more profitable and cost effective to merely "flash" the plated materials located inside computer components instead of how they once heavily plated the components. 
This would reduce yields for recyclers making a tough business even tougher,.
I can state it as such, I learned how to refine the precious metals by recycling a few PC towers years ago, the amount I found in that process was... Not relevant, it was the knowledge of the process that was most valuable, so I could further my endeavours in the mining industry. 
My suggestion to the recycling community is, get up, get out, and have fun... Safely. Mining season 21is here and the picking is good. If you would like to arrange a visit to my location or are interested in other locations pm me. B-)


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