# Gold Content of Scrap Items Series: Slotted CPUs



## lazersteve (Aug 3, 2007)

All,

This is my second installment in a series of posts detailing the yields of harvesting various scrap items. 

This installment in the series will show the yield data on Slotted CPU Fingers from processors as seen here:







I determined this information based upon 48 pounds of slotted cpus weighed without heat sinks or plastic housings.

Here's the two boxes of the slotted cpus after the fingers were removed:






*The CPUs shown above are PIII slotted cpus. Thirteen of these cpus weigh 1 pound and produce 34 grams of clean cut fingers. The cpu cores do not easily remove like the PII's, so they will remain with the cpu board for future processing.*






*The CPUs shown above are PII slotted cpus. Ten of these cpus weigh 1 pound and produce 26 grams of clean cut fingers. The cpu cores easily remove and will be saved for future processing. A shot of the PII cores is shown below*






*Here's the 1347.5 grams of fingers cut from 48 pounds of slotted cpus:*






*The baggie weighs 12 grams so the actual finger weight is 1335.5 grams.*

Now for the reaction information:

The 48 pounds of slotted cpus yielded 1335.5 grams of fingers. The fingers were processed in a mere 20 hours using rejuvenated AP. The AP was left over from processing the ISA fingers as seen in the AP video. It was rejuvenated by bubbling air thru it until the color turned transparent light green before adding the slotted cpu fingers. Air bubbling was continued during the etch process in addition to manual agitation. Here is a shot of the etch in process:






The resulting foils were washed as usual and then dissolved using HCl-Cl. The foils required 3/4 cup of HCl and 1/4 cup of clorox to fully dissolve. The pure gold mud was rinsed three times with hot tap water after precipitating with SMB. Here is a shot of the gold button produced:






*The button weighs 6.5 grams.*

Finally the yield data is as follows:

*(454 * 6.5) / 1335.5 = 2.21 grams Au per pound of slot 1 cpu fingers.*

From this the yield data per pound of slotted clean cpu cards is :

*6.5 / 48 = 0.1354 grams of Au per pound of slotted cpus without heat sinks or plastic housings.*

and lastly average yields for slotted cpu is :

*0.1354 / ((10 + 13) /2 ) = 0.0118 grams Au per CPU* 

My next installment will show yield data for medium grade header pins from 28 pounds of boards.

Your comments and questions are welcomed.

Steve


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## badastro (Aug 4, 2007)

Hmmm... so it comes out that each finger is worth about 25 cents.... 

The last time I sold scrap metal, computer cases were worth $70 a ton. That works out for the steel to be worth a little more than 3 cents a pound. If a single computer case is 10 pounds ( the number varies, and 10 is an estimate), then each computer case is worth 30 cents....

As an estimate, it took about 550 slot processors to produce $135 of gold. If those 550 computer cases were 10 pounds of steel, then you'd have 5500 pounds of steel, which is worth $192.50 at $70/ton :shock: :shock: :shock: .

Where do you get all those processors? :?: :?: :?:


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## aflacglobal (Aug 4, 2007)

Super great Steve. This man does it A-Z. 
Talk about multi-tasking.

:wink:


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## lazersteve (Aug 4, 2007)

Astro,

I collect them from many different sources. The bulk of which I buy from ebay when I find someone selling them for a fair price. I've got about another 60 pounds on hand to process before my well runs dry for now.

Steve


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## Charlena (Oct 22, 2007)

Look up user char_ed theres a nice lot going on there 
eBay of course.


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## Anonymous (Apr 28, 2008)

I am trying to figure a true end cost basis using the per pound factor of your original equation so as to surmize the actual or real profit gained.

My question is: Do you have any idea on the # of units (hours) of time and material costs (chemicals, gas, equipment, etc.) used to collect and process these parts? Ultimately, the results from the expanded equation coupled with the market price of gold will determine if it fits the economies of my time and money to process.

Thank you for your previous postings and any future assistance you might provide.


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## banjags (Apr 28, 2008)

The fastest way to turn a profit from gold fingers is to sell them on ebay by the pound. Alot of the guys on this forum do this for the love of refining not necessarily for the profit margin. When I started this in hobby/business I had every intention of processing everything myself... I am young and have bills to pay and need to turn money fast so most of my stuff hits ebay and I have a guy that buys boards for $1 each and he pays shipping. I do keep some to process myself as I do enjoy doing it.


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## sh3030 (May 27, 2009)

banjags,

what kinds of boards are you selling for $1 each??

I have tons of stuff here!!


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## Palladium (Nov 7, 2009)




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## copperkid_18 (Jul 8, 2010)

Steve,

how would you process the main processors on the boards?


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## lazersteve (Jul 8, 2010)

copperkid_18 said:


> Steve,
> 
> how would you process the main processors on the boards?



1. Remove the cpu form the card sorting the brown ones form the green ones.

2. Remove the lids and ceramic capacitors from the green ones using heat.

3. Process the ceramic capacitors for Pd.

4. Process the cpu housing in AP or 35% nitric to remove all of the solder.

5. Shred and crush the remaining housings once free of solder.

6. Incinerate if you are set up for it, skip this step if not.

7. Leach the resulting powder with AR or HCl-Cl.

I have had decent success panning the resulting powder from the crushed cpus to get the gold wires that are trapped in the epoxy. One day I'm hoping to find a chemical that will dissolve the epoxy and leave the wire and cpu die behind.

Steve


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## dtectr (Jul 8, 2010)

lazersteve said:


> copperkid_18 said:
> 
> 
> > Steve,
> ...



steve
this from my post on dissolving "something" from hybrid chips. i don't know if this product is still available, but ...
*Re: Hybrid chips embedded in goo*
"when i worked at a jewelry store/custom casting shop we manufactured lapel pins with colored epoxy as enamel. Very tough stuff. When we had to repair rejects the only product that would touch it was MethylEthyl Ketone (MEK), but it was awesome. Just submerge the part in it and after a good soak, the epoxy came out in pieces with no residue left on rhodium-plated SS or 10k gold. This is significant since my boss would blast the intaglio surface with glass beads to ensure a good bond.

"Don't make the mistake i made of cleaning the pieces barehanded. it absorbs through your skin & is excreted through your breath, sweat & urine. You can imagine what it does to your organs. However, the safe, responsible use of it created no problems. in fact, it worked so good the EPA probably took it off the market & failed to find a suitable replacement.

"just my "dos centavos"."


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## lazersteve (Jul 8, 2010)

I saw the post a day or two ago.

The epoxy I'm referring to is solid at room temperature and very hard. If you have a PII cpu or Celeron fiber cpu you can see this first hand but looking at the bottom of the cpu.

Steve


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## bagus (Jul 9, 2010)

Hi Steve, 


lazersteve said:


> 1. Remove the cpu form the card sorting the brown ones form the green ones.



What did you do with the brown cpus?



lazersteve said:


> 3. Process the ceramic capacitors for Pd.



which one is the ceramic capacitor in the CPU?


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## lazersteve (Jul 9, 2010)

The brown epoxy chips contain only traces of gold per pound. The only feasible way to recover the gold would be grinding and leaching or incineration followed by leaching, but keep them separate form the green ones.

The capacitors are the tiny tan-brown colored rectangles mounted on top of the cpu around the heat spreader.

Steve


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## dtectr (Jul 9, 2010)

lazersteve said:


> I saw the post a day or two ago.
> 
> The epoxy I'm referring to is solid at room temperature and very hard. If you have a PII cpu or Celeron fiber cpu you can see this first hand but looking at the bottom of the cpu.
> 
> Steve



as was the epoxy we used.
jordan


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## qst42know (Jul 9, 2010)

Unfortunately detaching epoxy from a metal surface is a long way from dissolving it.


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## dtectr (Jul 9, 2010)

qst42know said:


> Unfortunately detaching epoxy from a metal surface is a long way from dissolving it.


have you ever used this product? you talk like you have.
For anyone else who'd like to try it before dismissing it, here's some info: 

You don't need to DISSOLVE cured epoxy resin - for example, epoxy is often an ingredient in solder mask, and as we saw from lazersteve's video its bond can be broken down enough to allow its easier (not necessarily easy) removal from the circuit board. you merely need to weaken its crosslinks, the source of its strength & rigidity. It may then be able to be processed safely or easier by other means, such as incineration, or even mechanical methods (milling) or a combination of both.
"The strength of epoxy adhesives is degraded at temperatures above 350 °F (177 °C)' - _Wiki_

An example is floor finish, actually an acrylic polymer emulsion with a strong metal crosslink. when it is "stripped" it isn't "dissolved" as some would say. rather, the stripping solution is chemically formulated to break its link, both with itself & the substrate, in this case vinyl flooring.

a polymer (or copolymer, as epoxy) doesn't WANT to stick to anything other than itself, though it has an affinity for doing just that. using the proper solvent allows it to do what it wants to do anyway, release from its substrate.

here are some links:
http://en.wikipedia.org/wiki/Resin
http://en.wikipedia.org/wiki/Butanone
http://en.wikipedia.org/wiki/Epoxy
BTW - i looked at the bottom of butanone page & apparently it is used in mfr. of illegal drugs. one more chemical to make us look like suspects. :roll: 

if anyone can find some & try it, please let me know how it works.
thanks.
jordan


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## qst42know (Jul 10, 2010)

Years ago a friend of mine was in the electronics industry. They used MEK to peek into competitors potted circuits. It will separate some bonds but still requires prying, peeling, and much digging.

Gold in the form of fine wires still trapped in the epoxy is the issue. Digesting these wires from the exposed tip is not completely effective. Proper incineration or fine grinding may be the only method that is.


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## lazersteve (Jul 10, 2010)

I've been down this road before. 

I've tried pressurized reactors, hot sulfuric acid, small scale incineration, breaking the cross links with solvents, etc.

So far incineration is the very best method. 

I'll talked with several manufacturers of the Dynasolve products and never was able to get my hands on a sample for testing. One of the forum members obtained a 55 gallon drum of the stuff from a NASA auction a while back and mentioned he may want to sell it. I never followed up on it due to time restraints.

Here's the post:

Dynasolve 185

If you can get your hands on any let me know.

Steve


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## qst42know (Jul 10, 2010)

If only to have NASA's budget. :mrgreen: 

I hope you find some to try however it remains to be seen if this elusive solvent could be cost effective.


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## bagus (Jul 10, 2010)

lazersteve said:


> The brown epoxy chips contain only traces of gold per pound. The only feasible way to recover the gold would be grinding and leaching or incineration followed by leaching, but keep them separate form the green ones.
> 
> The capacitors are the tiny tan-brown colored rectangles mounted on top of the cpu around the heat spreader.
> 
> Steve



so the capacitor is in the brown cpu right? because I can't find it in the green cpu


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## lazersteve (Jul 10, 2010)

The red boxes show the capacitors on the green fiber cpu:







Steve


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## glondor (Mar 21, 2011)

Hey Lazersteve, did you ever quantify the values in the P3's slot card and CPU after the fingers were off?


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## lazersteve (Mar 22, 2011)

Nothing scienctific yet. I have found that it is best to dissolve out the solder from the through holes then separate the epoxy center section from the laminations of the green fiber cpu. 

The epoxy section is then crushed and leached or panned for the gold wires.

Incineration of the epoxy central section makes crushing easy as pie. Avoid the toxic vapors that emit from the burning epoxy.

Steve


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## glondor (Mar 23, 2011)

Do you incinerate these your self Steve or do you have a place that does if for you.


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## lazersteve (Mar 23, 2011)

I've incinerated a few small samples as a test to see how the epoxy would react. Nothing on a scale larger than a few pieces.

Steve


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## Militoy (Apr 17, 2011)

We manufacture potted electronic and electromagnetic assemblies, and occasionally need to remove epoxy potting compounds to perform destructive physical analysis (DPA), or repair. I've found most modern cycloaliphatic epoxies to be fairly impervious to MEK - that's even one of the standard solvents used in the resistance-to-solvents test. We soak in a commercial paste-type paint stripper to soften the epoxy into mud - and dig out the epoxy by hand. I believe on a commercial level - crushing / grinding and incineration is likely to be the most economical method.


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