glorycloud
Well-known member
Um, is it industry standard or forum standard to handle hot acids without protective gloves on? :shock:
Owltech said:kernels said:Hi there forum gurus,
Was hoping for a bit of advice about how to deal with the types of processors shown in the picture. They have the big and heavy integrated, plated heatsinks which I assume are Copper based ?
Thanks!
Big_Gold_Tops.jpg
Hi I would like to share my experience with these CPUs:
from AMD K5 gold top/ gold lid 10 CPUs 378g 2.45g Au or 6.48g Au/kg https://youtu.be/eJwodZri9qM
from 10 IBM 686 & 10 Cyrix 686 CPUs mix 830g 2.45g Au or 2.95g Au/kg https://youtu.be/irMDfWA5SM8
plus
from 4.96kg i386 & i486 ceramic CPUs mix 43g Au or 8.67g Au/kg https://www.youtube.com/playlist?list=PLLm8aBXzLPMM_NHr8UxLkDfOgApABQrzO
from 1,028kg AMD 486 5.9g Au or 5.73g Au/kg https://youtu.be/xHJ7RoglI_0
from 10 AMD 386 162g 1.57g Au or 9.69g Au/kg https://youtu.be/DLAmanHvUxM
also, I've noticed something peculiar:
about 0.046g Au per gram of kovar lids (I've got almost the same yield from all kovar lids processed so far, regardless of the manufacturer)
another observation I've made (when it comes to ceramic CPUs with gold plated kovar lid only) is the corelation between the yield form the lid compared to the overall yield of a CPU (38-40% of the gold is in the lid)
maybe it's all just a coincidence but I still find it strange...
lazersteve said:If you follow Sam's protocol you will be hard pressed to recover all of the silver and you will be picking tungsten shards out of the left overs if you want to sell it for an additional profit
Tungsten dissolved in AR also gives false positives to the stannous chloride test. As an added issue the tungsten will leave a yellow layer in your beakers and buckets. The yellow tungsten oxide can be removed, but it is just one more step you will need to perform to keep your reaction containers free of contaminates.
Steve
lazersteve said:The copper/tungsten heat spreaders are soldered on with silver alloy braze. They easily fall off when free of grease and stickers and the chip is allowed to soak in dilute nitric acid. You end up with gold foils from the lid, a clean tungsten plate, a ceramic cpu housing, kovar plated gold legs, a cpu die, gold bonding wires (if present), and a solution containing copper and silver nitrate. Remove the gold plated bottom lids if you are working with cpus that have them (P60/75/90, etc). For ceramic bottom lidded cpus simply fracture the bottom lid enough to allow the acid into the core/bonding wire area of the cpu (expose the core).
Steve
anachronism said:lazersteve said:The copper/tungsten heat spreaders are soldered on with silver alloy braze. They easily fall off when free of grease and stickers and the chip is allowed to soak in dilute nitric acid. You end up with gold foils from the lid, a clean tungsten plate, a ceramic cpu housing, kovar plated gold legs, a cpu die, gold bonding wires (if present), and a solution containing copper and silver nitrate. Remove the gold plated bottom lids if you are working with cpus that have them (P60/75/90, etc). For ceramic bottom lidded cpus simply fracture the bottom lid enough to allow the acid into the core/bonding wire area of the cpu (expose the core).
Steve
Hi Steve
I'll try a batch your way this weekend. Always up to try a new method. Let me know what strength of Nitric you class as dilute for these purposes please would you? My raw Nitric is 67% so what would I add?
Thanks in advance
Jon
lazersteve said:Jon,
You should try the process on some cpus with the tungsten heat spreader. These are the types of cpus where this method really shines as you will recover the Ag from the braze as well as the tungsten from the spreader.
Steve
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