Non-Chemical Fried Green Fiber Cpu's

[GotTheBug]

Had a few, thought I would incinerate and see. Looks like a bit of copper, with a couple that look plated.

Planning an HCl bath, roasting, then nitric to get the copper.

Thoughts?

 

[g_axelsson]

Do you have a picture of the starting material? I can at least think of two different types of capsules that would fit "green fiber cpu's".

Göran

 

[GotTheBug]

No pics of the very start, however... Few were IC chips, as in other than cpu. Most are actual cpu, as in under heatsink and cooling fan on motherboards.

One interesting thing I noticed is the layer that appears to be copper has a distinct purple tinge.

All of this actually started on the search for the elusive bonding wires in their natural habitat.

Paul.

 

[solar_plasma]

More reading would have saved you some time and work.

 

[resabed01]

Did you remove the pins first to process separate? I think you'll find the pins hold most of the gold on these. The green and brown fiber flip chips don't have gold bond wires. The silicon die is flipped and bonded to the fiberglass body with micro sized balls of solder. Then a dab of epoxy sealant to hold it in place. The green and brown fiber cpu bodies do have a small amount of gold plating. If you have a lot of them AP would be the way to recover this.
You'll find bond wires in chips that are encapsulated in black epoxy (black fiber, BGAs and regular black ICs). Hint: Chips with black epoxy get incinerated to release the gold bond wires.

 

[Geo]

Search the term "flip-chip". Bases that have the die (silicon chip) exposed on top of the base contains little to no PM value outside the gold plated legs.

 

[GotTheBug]

Good thing I took the legs off and processed separately. Lol.

Where would we be if not for rookie mistakes! Truthfully I was running this one as a test, just to see. Looks like I might just end up with a tiny bit of copper and spend 50 times the value recovering it.

Thank You guys for the input, it always helps!

 

[resabed01]

If you wanted to continue on to process, I'd recommend several water washes to remove the ash. Keep washing until the rinse water is no longer cloudy. Then do a soak in HCl to remove the tin.
After that you could use AP to remove copper and any other base metals that might be present. Whats left can go to HCl/bleach to dissolve any recover your gold.
In the end you might find that's lots of steps and time to recover a tiny amount of gold. Fiber CPUs don't have very much to recover, like I said, most of the value is in the pins. And from what I can tell that's not much either. I've read yields are around 0.5g Au per 100g of CPU pins.

 

[GotTheBug]

If you wanted to continue on to process, I'd recommend several water washes to remove the ash. Keep washing until the rinse water is no longer cloudy. Then do a soak in HCl to remove the tin.
After that you could use AP to remove copper and any other base metals that might be present. Whats left can go to HCl/bleach to dissolve any recover your gold.
In the end you might find that's lots of steps and time to recover a tiny amount of gold. Fiber CPUs don't have very much to recover, like I said, most of the value is in the pins. And from what I can tell that's not much either. I've read yields are around 0.5g Au per 100g of CPU pins.

Thank You Resabed, that's almost exactly what I was thinking.
What do you think of a roast after HCl and then nitric to remove copper?

 

[resabed01]

If it were me I wouldn't use nitric to remove copper. I find it too expensive to use like that and on such a low grade scrap. My choice would be AP after the tin removal so incineration between these steps would be unnecessary.

 

[GotTheBug]

Good point, though the price isn't too much an issue when you make it, even if it is a pain in the butt. Once again worth the knowledge gained I suppose.

I believe I'll do some serious HCl ing first though.