# Motherboard yield report.



## zzz (Dec 20, 2012)

Hi everyone.
I've recently termined a little specific test on 16 of latest type of mixed brand motherboard (asus, gigabyte, asrock for cpu without pin) and performed gold extracting from every single plated pins and chip.
Collected around 195 grams of mixed chip that give me a little button of exactly 0,5 grams of pure gold (i think with a lost of 0,05 grams for gold in crucible and other things);
the gold of plated pin is lost in the sulfuric...two day of waiting to settle and nothing is appeared (the sulfuric was a little dirty), so i lost sight of. 

Regards.


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## gold4mike (Dec 20, 2012)

16 modern motherboards is roughly 16 pounds. Boardsort currently pays $2.15 per pound for mixed small socket motherboards, or +/- $34.40 for 16 boards.

You got .55 grams (including what you think you lost) from them which, at current spot value of $1642.00 per ounce of gold, is $29.03 worth of gold from processing them.

It still looks like a good idea to "cherry pick" the best stuff for yourself and sell the rest. Take the money and buy gold.


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## zzz (Dec 20, 2012)

It was only a test. I've lost the gold of pin, i think could be almost another 0.5 grams. The weight of motherboards lot weight exactly 10.2 kilos.


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## jimdoc (Dec 20, 2012)

zzz said:


> It was only a test. I've lost the gold of pin, i think could be almost another 0.5 grams. The weight of motherboards lot weight exactly 10.2 kilos.



How did you process all this? It sounds like you used the sulfuric cell?

Jim


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## gold4mike (Dec 20, 2012)

zzz,

Your location doesn't show but, since you're using kilos rather than pounds, I assume you're probably not in the U.S. and Boardsort wouldn't be a viable option for you anyhow.

I've been curious as to what our recoverable yields might be. I've heard that, although they have less gold, the "China" boards have more palladium which makes up for it in value.

Are you planning to recover any metals besides the gold?


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## samuel-a (Dec 20, 2012)

Hello zzz

Not trying to deminish your test results, but in order to truly assay the value of any board for all its worth (all metals content), one would need to:
Manually remove ferrous parts (if present)
incinirate
seperate ashes from metallic parts
crush and mix ashes with flux and collector
Smelt the ashes (all metallic parts placed also at the bottom of the crucible)
xrf the resulting bar or process it for PM's

I have recently finished building a gas furnace and will probably preform many assays for boards, hopefully i could share some of the results here as well.


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## Geo (Dec 20, 2012)

very nice Sam. is that ceramic wool insulation?


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## samuel-a (Dec 20, 2012)

Yes Geo

I decided to use wool (rated for 1250C/2282F) instead of refractory casting... pure headache if you ask me...
Two layers which amounts to 2 inches.


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## nh6886 (Dec 20, 2012)

Sam

Have you ever used a rigidizer on your ceramic fiber? There are some great products that do more like ITC-100 which is very popular with forge users because it's also an infrared reflector. But I use a simple rigidizer in furnace applications where high velocity air erodes the fiber. It works best sprayed on, nothing fancy just a garden sprayer. However for small stuff a brush works fine. I would be happy to send you a few ounces to try if you're interested send me a PM. 
Just to be clear for anyone wondering this is not something I sell and the company I work for only sells services so I have no commercial interest in this. Just thinking this might extend the life of your furnace and keep the wool out of the assay/air.

All the Best,
John


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## zzz (Dec 20, 2012)

I know, the secret for recovery metal from information tecnology stuff is to melt everything into furnace with an excess of copper, than do the electrolitic refining of copper and recover the anodic slime for precius metal. Less noble metal go into solfuric solution.


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## zzz (Dec 20, 2012)

jimdoc said:


> zzz said:
> 
> 
> > It was only a test. I've lost the gold of pin, i think could be almost another 0.5 grams. The weight of motherboards lot weight exactly 10.2 kilos.
> ...


Yes, i used sulfuric cell to strip pin.


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## zzz (Dec 20, 2012)

gold4mike said:


> zzz,
> 
> Your location doesn't show but, since you're using kilos rather than pounds, I assume you're probably not in the U.S. and Boardsort wouldn't be a viable option for you anyhow.
> 
> ...



Infact i'm from Europe. Right now i'm not interested to other metal than gold and pgm. In future i'll maybe recover everything.


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## skippy (Dec 20, 2012)

zzz that's very interesting and thanks for sharing, I don't think many people here have done what you have! You didn't recover any gold bonding wires from your chips, did you? 

I wonder how much you had on the pins too. You might try diluting your sulfuric to see if your gold sinks, and check it with stannous too in case there was contamination in your sulfuric that dissolved any of your gold. If it still doesn't settle, or if stannous tests reveals dissolved gold, I would dissolve all of the gold by adding some salt to your diluted sulfuric acid and then a wee bit of nitric. Filter the solution, cement it out and then refine your gold and weight it.
Just my idea on how to work this, any comments from anybody?


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## patnor1011 (Dec 20, 2012)

skippy said:


> zzz that's very interesting and thanks for sharing, I don't think many people here have done what you have! You didn't recover any gold bonding wires from your chips, did you?
> 
> I wonder how much you had on the pins too. You might try diluting your sulfuric to see if your gold sinks, and check it with stannous too in case there was contamination in your sulfuric that dissolved any of your gold. If it still doesn't settle, or if stannous tests reveals dissolved gold, I would dissolve all of the gold by adding some salt to your diluted sulfuric acid and then a wee bit of nitric. Filter the solution, cement it out and then refine your gold and weight it.
> Just my idea on how to work this, any comments from anybody?



That half a gram he reported was from IC chips and from amount of chips he collected result is pretty much in line with cca 2g+/kilogram of mixed IC chips.
There may be some additional value in resistors and monolithic capacitors.


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## zzz (Dec 21, 2012)

Yes, the yield is only from mixed chips. I'm trying to recover the gold from the sulfuric, i've already diluite it, the first part is negative and full of a dark grey sponge that i think is some base metal persulfate (insoluble in almost nothing, also ar), now i have another diluite part that i left settle for all day...now i'm going to check.


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## zzz (Dec 21, 2012)

No gold also in secondo part. I think that the quantity of gold was so little that can not be recovered with these circumstances (dirty sulfuric).
Regards.


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## voeckel (Dec 25, 2012)

Hi gentlemen,
Merry Christmas everyone! 

Regarding the yield of motherboards, below is a paragraph from a chinese research paper. read carefully for the numbers bug me all the time here and can't be right.



> "In general, waste PCBs contain approximately 30% metals and
> 70% nonmetals. The typical metals in PCBs consist of copper (20%),
> iron (8%), tin (4%), nickel (2%), lead (2%), zinc (1%), silver (0.2%),
> gold *(0.1%)*, and palladium (0.005%). The purity of precious metals in waste PCBs is more than 10 times higher than that of rich-content minerals."



This would mean that there would be typically 1 KG of Au in a MT of PCBA scrap! 

What can the ones with commercial experience tell us please? I think, this must be way, way off. Maybe 1/10 of this or even less? 
As you can see they do not even provide details on the board grade used for the tests to get these numbers. :roll:


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## Geo (Dec 25, 2012)

0.1% is about right from my experience. individual components yield different totals but given the overall weight of a motherboard,it sounds right. of coarse you would have to include the CPU with the motherboard.


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## voeckel (Dec 25, 2012)

Geo, doesn't that sound somehow too good to be true? Ok, here some maths on this.

Assumptions:
1 motherboard incl CPU (roughly 30-50g average, 450g for board taken from above) = 500g
1MT therefore around 2000 boards with CPUs (let's be generous on the estimate here, not a scientific paper, just trying to create a guideline somehow)
1 CPU average Au content = 0,6g
2000 x 0,6g = 1,2Kg Au
This would be already 20% over 0,1% (1,0Kg) of 1MT :arrow: :?: 

Not to mention the 20% out of thin air, where is space here for the Au of bridges, ICs, connectors, card slot pins, etc?

Got lost somewhere on the way. No matter how much i turn and tweak it, i can't get the round hog through the square hole here...

EDIT:
I see my mistake! God, that would be the greatest find ever... assumed average for one CPU is not *0,6g* but *0,06g*!

Hence, even if the CPUs would have an average of 0,12g, there would be lots of Au space left to get the one Kg. :idea: 
Let's assume therefore the 0,12g and we would end up with 240g Au from CPUs and would still have 760g Au left from the boards themselves.

...

Sounds still very, very high to me...


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## glondor (Dec 25, 2012)

Voeckel, is there a date on that study?


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## NoIdea (Dec 26, 2012)

I thought a more lower estimate of 0.05 - 0.1g per CPU would be more realistic, well maybe?  

Deano


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## Geo (Dec 26, 2012)

when your talking about averages, i guess its all relative. ive seen motherboards that was loaded with flatpaks and ive seen the cheap Chinese boards that didnt even look like the pins were plated.ill get some better yield info when summer gets here and i can set up a copper parting cell. honestly, thats the only way to know for sure. cast all the metal from a random sample in an anode and part the copper and refine the metal.


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## rucito (Dec 26, 2012)

30% of 450 = 135gr. metals in 1 board
0.1% of 135 = 0.135gr. gold


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## voeckel (Dec 26, 2012)

NoIdea said:


> I thought a more lower estimate of 0.05 - 0.1g per CPU would be more realistic, well maybe?



It was a generous deduction to see what's left for the boards themselves once you take off the CPUs. But there is still a mistake in my calculation due to applying the values to 100% of the total weight, not to the 30% metal content! That's why the numbers still seemed to be very high to me.

Hence below is now a final calculation to clean up the mess a bit. 

Baseline:
1 MT of boards with CPU = 2000 boards
1 MT = 300 Kg of metals
0,1% Au of 300 Kg = 300g Au (including CPU on board)
Au content of average CPU = 0,07g
2000 x 0,07g = 140g Au in CPUs

300g Au board in total - 140g Au CPU in total = PCBA Au content = 160g/MT

Should be a good guideline now for motherboard yields, although it does not mention any board grade. Let's assume therefore that it is a colorful mix of grades and the numbers come from an average of 100 MT of processed boards. :idea:


EDIT:


> 0.1% is about right from my experience. individual components yield different totals *but given the overall weight of a motherboard,it sounds right*. of coarse you would have to include the CPU with the motherboard.



Geo, are you sure that this would be really right on the overall weight of the board (so the 100%, incl the 70% non-metal fraction)?? If so, then my previous calculation would have been right but honestly, I doubt it a bit. Just want to be sure on the statements here so that we don't publish a lot of wrong calculations for newbies.
Please let us know once you made your test.


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## samuel-a (Dec 27, 2012)

Voeckel

160g per MT is very low.

Typical assay for mixed MB types ranges from 240g to 350g Au.

Though, maybe colorful MB could yield this low... 
Yield are a tricky business... You have to define the source material very particularly.


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## zzz (Jan 1, 2013)

Processed with nitric the skeleton of this chip:
recovered some silver, i think 2 to 4 grams. I'll make and weight the button in 2/3 days. 
See you.


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## Geo (Jan 1, 2013)

i have three months of winter left and from the looks of it,its going to be a wet one. when you talk about yield of a particular board, there are variables from board to board even in like models due to costumer specifications. on older models,0.1% may be low and on newer models it may be a little high. you have to consider that most computers were built very specifically for each individual and components from board to board will vary. the hidden gold on a motherboard may exceed the visible gold by 2 to 1. there are motherboards that appears to have no CPU but rather are covered in flatpak chips. these have no VGA chips (north/south bridge) but still contain much more gold than boards with a processor. 

this can go on and on. even if you took two of the same boards from the same computers,they could still contain different amounts of precious metals.


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## johnjohny (Jan 30, 2014)

Hi,
apologies for reviving ancient thread. Got bored so started reading forum and found this topic with a bit of inconsistency.



voeckel said:


> > "In general, waste PCBs contain approximately 30% metals and
> > 70% nonmetals. The typical metals in PCBs consist of copper (20%),
> > iron (8%), tin (4%), nickel (2%), lead (2%), zinc (1%), silver (0.2%),
> > gold *(0.1%)*, and palladium (0.005%). The purity of precious metals in waste PCBs is more than 10 times higher than that of rich-content minerals."




Anyhow I am calculating I can't get it right.
If copper + other listed metals are listed as % of 30% then copper would amount to 20% of 30% = 6%. That would mean that the other metals listed (and non listed) woudl have to make the remaining 94% (out of 30%). It doesn't add up.

If copper + other listed metals are listed as % of total weight then just the listed metals would consist more than 30% (20+8+4+2+2+1...) and apparently metals are 30% of total weight. It doesn't add up either.


Don't know where the information came from, but looks very fishy.
There is a possibility that I am missing something and if so I'll be thankful if somebody points out my mistake.

Regards


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## etack (Jan 31, 2014)

I think you are taking "approximate" numbers literal. Approximate will have some deviation to them. (+-) 6% on metal content of PCB MB is very possible.

Eric


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## g_axelsson (Jan 31, 2014)

I can't see aluminum in that list. It would be a large part of the metals in a PCB.

Göran


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## Smack (Jan 31, 2014)

It depends on pre-processing of the boards before they are processed and made into dore bars. There is very little aluminum on the boards I take in.


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## g_axelsson (Jan 31, 2014)

Even electrolytic capacitors are removed? But if this is a test made on dore bars then I can understand it. Aluminum is really hard to alloy with some metals and I guess most of it will oxidize and end up in the slag.
Other metals I would expect but didn't see is tantalum and beryllium, not so big parts but still metals that exists on boards. But then that list never claimed to be complete.

Göran


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## Smack (Jan 31, 2014)

Yes even those, I would say at least 85 to 90% of them and the Ta caps too. For me if I have time, after cherry picking the boards for the stuff I want to process myself, I take off as much stuff as I can that I will not get paid for from the refinery. For every pound I take off in material they don't pay me for I save a dollar ($1.00 per pound processing fee) and if I can take that same material and sell it for lets say $.25 per pound, I'm $1.25 to the good. The electrolytic caps I sweat to get the aluminum and sell that as Old Cast Aluminum for $.50 per pound and whats left after that process I throw in with the sheet steel and make an additional $.12 per pound. The only thing I'm taking off that I don't have a market for any more is plastic but I'm still saving $1.00 per pound. You might say, (Well how much does all that time cost you?) and like I said before, if I can do it and still keep up with the flow of material then it costs me nothing but my time. I have a couple of retired guys that like to come and tear stuff apart for something to do. Gets them out of the house and keeps the relationship with their wife good as it gives the women a break from the men too.


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## g_axelsson (Feb 1, 2014)

That's nice, Smack, and I would do the same with my scrap if I sent it for refining and not selling it.
But as a basis of calculate metal contents in general motherboards you are skewing the numbers. Taken to an extreme I could state 100% Au in motherboard, as that is what I get in the end. :mrgreen: 

Göran


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## Geo (Feb 1, 2014)

it cant be a true analysis of percentages unless there can be an agreement on what the beginning measurement will be. if you detract from the weight of the motherboard straight out of the computer, your percentage will vary from each individual that tries to quantify them. did you remove the heat sink? did you remove the CPU? did you remove capacitors? of coarse there are computers like the early Apple's that did not have a CPU and there weren't any electrolytic capacitors. if the subject was divided into models or even series, then data could be reliably obtained. even then, like i said before, even computers with the same model numbers may have different components installed. i believe that instead of trying to get a definitive percentage amount, it would be easier to set a baseline amount (e.g. no motherboard should have less than X amount). even if you or i swear that the stack of motherboards SHOULD contain this much gold that you know for sure that it DOE'S contain at least this much gold.


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## Smack (Feb 2, 2014)

I was, I guess on a slightly different topic and not so much percentages of metals in motherboards. Nothing is skewed, I was talking about the stuff I take off all boards.


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