Gold finger cards analysis result

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kjavanb123

kjavanb123

Well-known member
Joined
Apr 1, 2009
Messages
1,746
Location
USA
All,

I finally recieved the ICP result for my sample alloy from smelting few pieces of gold finger cards inside an induction furnace, Cu at 58% and Zn at 38% were the majority of base metals in them. I am still pending for result of gold and palladium.

Regards,
Kevin
 
This really means very little without knowing what weight you started with and what weight the metal you had assayed was. In other words, what percentage of the start weight was reduced to metal? Something else is odd about the result, one of the nice things about an ICP analysis is it simultaneously gives the analyst all of the metals in the sample. Seeing as the metals you are looking for Cu, Zn, Pt, and Pd are all soluble in aqua regia, any analyst would run all of the metals at once. So why are Pt, and Pd pending?
 
4metals,

The smelting was done on 4 graphic and sound cards, I don't have the exact weight of sample I smelt, but the weight of refiner's bar was 55 grams. This is the ICP analysis on this 55 grams sample alloy,
View attachment Gold finger cards analysis.pdf

I requested the test for Gold in the sample to be conducted fire assay, they said that result will be available on Tuesday. I haven't requested for Palladium, I will though soon. But no trace of silver in it.

Thanks and regards,
Kevin
 
kjavanb123 said:
4metals,

The smelting was done on 4 graphic and sound cards, I don't have the exact weight of sample I smelt, but the weight of refiner's bar was 55 grams. This is the ICP analysis on this 55 grams sample alloy,


I requested the test for Gold in the sample to be conducted fire assay, they said that result will be available on Tuesday. I haven't requested for Palladium, I will though soon. But no trace of silver in it.

Thanks and regards,
Kevin
Click to expand...

The lack of Ag is interesting. I wonder if it burnt off in the melt. what was the temp you melted at?

Eric
 
Eric,

The temperature outside the graphite cruicble was 790c, but inside must have been plus 1000c. The pulp as butcher said is not analyzed.

Thanks
Kevin
 
Javan can I clarify a couple of points please?

Firstly you say 4 cards in total?
Secondly were the mounting plates removed from these cards?
Thirdly (although I think I know the answer to this) were all the heatsinks removed from the cards too?
Fourthly, I'm assuming that the cards were all ROHS compliant since the Pb content was so low?

Thanks in advance.

Jon
 
Jon,

Yes to all 4 questions. I will be posting a video that is shows the type of cards which was smelted


Regards
Kj
 
All,

I am shocked after receiving the fire assay result for the sample alloy from smelting graphic and sound cards. Amazing amount of gold in there wow. 3200 ppm???
I called the lab technician asked specifically how did they come up with this number and he told me they first dissolved the alloy which was mostly copper and zinc in nitric acid, and filtered the grayish residue dry it, then did fire assay on that residue, and here is the result;
View attachment gold finger card fire assay result.pdf

this is in practice means 3.2 kg of gold per processing 1 metric ton of gold finger cards?? I still can't believe it, and I am sure there is no contamination when I did smelt using induction furnace because I purchased the graphite crucible myself.

I have 50 lbs of shredded gold finger cards in the shop which I am going to try with the lab scale induction then dissolve the alloy in AR drop the gold with SMB and show the result.

Peace
Kevin
 
kjavanb123 said:
this is in practice means 3.2 kg of gold per processing 1 metric ton of gold finger cards?? I still can't believe it, and I am sure there is no contamination when I did smelt using induction furnace because I purchased the graphite crucible myself.
Click to expand...
I believe it means 3.2 kg of gold per ton of the smelted metal remaining from the cards, not from a ton of cards. You mentioned that you didn't record the starting weight of the cards. I would assume it was more than the 55 grams sample of metal you ended up with. Graphics cards may run higher than other types of cards.

Dave
 
3.2 kg of gold per processing 1 metric ton of gold finger cards??
Click to expand...

That would mean 3,2g gold per kg cards....I should throw away the flatpacks and use the rest of the boards, without those cheap 1g/kg flatpacks the board would become even more valuable :lol: no, that does not sound plausible. Is it possible, they have measured incorrectly?


edit: ok, Dave gave the answer :)
 
Edited after reading Dave's post properly.

So he's saying that 55g of "melt" showed 3.2Kg per tonne of gold.

That puts a different picture on it.

Thanks Dave
 
I've just re- read the OP.

Solar I see your point, is he talking about 3Kg per tonne for complete cards?

To add an edit- read the post above please - I didn't follow the thread correctly before replying. Apologies.
 
Dave,

Thanks for the point in calculation, but I still think that is pretty high number for the smelt alloy even if it is 1/3 of the complete cards weight, I had removed all the steel and aluminums from the sample cards, there were 4 cards in total I dont know the weight but I am sure you can estimate.

Assuming that number is true then we have 1000 kg of gold finger cards produce 300 kg alloy, if 1 ton alloy has 3200 ppm gold, at 100% recovery rate, then 300 kg alloy would have 3200 ppm / 3 which is 1066ppm of gold which is still pretty high.

Regards,
Kevin
 
4 cards 55g -> 73000 cards for one ton = 3200 g Au -> 0.044g Au / card -> 0.0014 oz t/card -> @1316$/oz t -> $1.8 / card.

... and of course, this can be wildly outside any real mean value over a large waste stream. You don't know the weight, just picking four cards you might have picked four good one without thinking of it. There is a lot more to taking a proper sample than just pulling some cards.

Göran
 
Where there any BGA chips on the cards?

3 g/BGA chip -> 333 chips / kg -> 5g Au / 333 chips -> 0.015g / BGA chip ... 1/3 of the gold is in the BGA chip.

Any flat packs? 1-4 g/kg (ref). Usually there are more mass in flat packs as they are more abundant. Let's say there were 10g of them and middle yield (2g/kg).

10g flatpacks -> 0.02g Au That's the second part out of three...

Oh, the obvious part, the fingers... What kind of cards were they? ISA, PCI, PCIe, VESA... it can vary a lot between cards and busses. How thick was the plating?
I just weighted a couple of fingers... no, not PCI or other PC bus, but I'm guessing that the fingers weight around 2.5g per card. Common yield numbers seems to be in the range of 2-6g/kg for fingers.

1 finger @2.5g -> 400 fingers / kilo -> 400 fingers / 4 grams -> 0.01 g Au / finger.

Let's see.... 0.015 + 0.02 + 0.01 = 0.045 g / card!

This is only an approximation I just did, sitting in my sofa, searching the forum. It took me 25 minutes and didn't cost me a cent. I'm a bit surprised that I came so close to your numbers.
So folks, the lesson of today is if you know your math and does a little research you don't have to spend a lot of money on tests to be surprised.
Nothing in this was a secret, it just needed to be compiled to show the bigger picture.

Göran
 
Goran,

Thanks for the detail calculation there. I will be getting an induction furnace in next few days and will start this 50lb batch of shredded mix gold finger cards. Then ball mill the result follow by sieve 10 micron, to separate plup and refiner's bars. Then dissolve the refiner's bar in nitric acid, filter the residue and dissolve in AR, drop with SMB.

Best regards,
Kevin
 
What is it that I didnt answer?

Also based on the analysis results here what would be the best options to separate Cu Zn and Au from smelted metal?
 

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