patnor1011
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I agree, plenty of Ag and Pd in chips. I once got them packed where it was written on package Ag/Pd plating.
Gold inside chips (black, flatpacks - not CPU)
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acpeacemaker
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Silicon chips, as in the wafer inside the actual chip, flatpack etc.
patnor1011
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Correct. It is just that small part which looks like mirror on one side. Like broken glass when crushed.
patnor1011
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That green bottom base do have some plating so that goes to AP.
We talk about BGA IC chip package which is green bottom and slightly smaller black plastic top. Bulk of gold, well over 95% is in black plastic top part.
The whole green BGA IC chip package which has very small silicon square top part comparing to bottom part and some monolithic capacitors - there I do not have any data on this one yet and never heard about anybody who processed them, I keep them but I do not expect anything from them so far.
I will try to do some experiments with them, I must have over pound by now.
We talk about BGA IC chip package which is green bottom and slightly smaller black plastic top. Bulk of gold, well over 95% is in black plastic top part.
The whole green BGA IC chip package which has very small silicon square top part comparing to bottom part and some monolithic capacitors - there I do not have any data on this one yet and never heard about anybody who processed them, I keep them but I do not expect anything from them so far.
I will try to do some experiments with them, I must have over pound by now.
srlaulis
Well-known member
I wonder if we could take the green wafer, after it is separated from the black top, and soak in AP or acid with a bubble stone, to remove excess metals. Then could we just soak the batch in HCl/clorox? I'm sorry if my post seems novice. I have been silently reading on this forum for months now, and this is my first post, lol. I am sure I am missing something with my proposed idea. I was just thinking that if you can dip gold plated dishware into HCl/clorox to remove gold plate, why couldn't we do the same with the green wafers once the junk metal is removed? Please be easy on me. :|
Geo
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That's exactly what you do with the green bases from north-south bridge chips. AP and then HCl/Cl for the loose gold foils.
srlaulis
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Do you think it is possible to just put the entire green wafer, after the AP bath, into the HCl/Cl in order to dissolve any gold that doesn't detach from the wafer?
Geo
Well-known member
Unless you had a bucket full, you wouldn't get enough gold to to make a difference anyway. It's best to collect the foils and process them. To try and do the entire base, you would wind up with more solution than you can deal with.
There is a danger with putting multi-layer PCBs (which the green bases are) into a gold solution.
It is very hard to remove all base metal inside the PCBs, if you put it into a gold solution, gold will start to deposit inside the PCB when the solution comes into contact with the copper. Then you will probably lose more gold than what you get from the few foils on the surface. Only way to prevent losing more than you get is to start with a totally barren solution and remove the PCBs before too much cements inside them.
I have done that error once when I ran two fiber CPUs together with some ceramic CPUs. I will provide pictures and a write up of it soon. The fiber bases is going to incineration and processing to get anything from the inside. I will not do that mistake again.
Better to take a sharp knife and just scrape off the foils on the surface and then wash it in a beaker with some water and a toothbrush. Collect the gold foils with solder masks and other dirt from the bottom and process them as usual.
Btw, incinerated black plastics is easily pulverized in ultrasound, and poured off as a cloudy fluid. The
bond wires, copper metal and silicon die is left very clean in the bottom of the beaker.
/Göran
It is very hard to remove all base metal inside the PCBs, if you put it into a gold solution, gold will start to deposit inside the PCB when the solution comes into contact with the copper. Then you will probably lose more gold than what you get from the few foils on the surface. Only way to prevent losing more than you get is to start with a totally barren solution and remove the PCBs before too much cements inside them.
I have done that error once when I ran two fiber CPUs together with some ceramic CPUs. I will provide pictures and a write up of it soon. The fiber bases is going to incineration and processing to get anything from the inside. I will not do that mistake again.
Better to take a sharp knife and just scrape off the foils on the surface and then wash it in a beaker with some water and a toothbrush. Collect the gold foils with solder masks and other dirt from the bottom and process them as usual.
Btw, incinerated black plastics is easily pulverized in ultrasound, and poured off as a cloudy fluid. The
bond wires, copper metal and silicon die is left very clean in the bottom of the beaker.
/Göran
patnor1011
Well-known member
Göran what device do you use for that ultrasound treatment?
Hi Partnor, I'm just using a small cheap bench system for cleaning jewelry. I normally use it to clean mineral specimens from clay.
I don't know how it scales, I only tested one flatpack, incinerated with a small pocket-torch, but it was quite fast and the filler that remains after the incineration turned into suspended clay and could be poured off, I never needed to pan any gold threads.
Just add a drop of detergent before sonication to stop the gold from being carried away by the suface tension.
/Göran
I don't know how it scales, I only tested one flatpack, incinerated with a small pocket-torch, but it was quite fast and the filler that remains after the incineration turned into suspended clay and could be poured off, I never needed to pan any gold threads.
Just add a drop of detergent before sonication to stop the gold from being carried away by the suface tension.
/Göran
Some pictures from my microscope...
Just as a proof of concept I took half a chip (I've already broken it in half to look for bond wires) and incinerated it. Then I put it in a beaker with water and a drop of detergent into a small ultrasonic cleaner (effect 70W). There was an instant cloud and I left it on for circa 20 seconds. Then I gently poured off the silty water and found that I hadn't incinerated long enough, there were half of the black plastic still left.
Another turn under the mini-torch and then back into the beaker and sonication.
The second time I managed to burn off almost all carbon. The end result was a tangle of wires, some copper wires from traces from the base PCB that stuck to the black top when I ripped it off and the rest golden bond wires. (picture 3) With it was some small white sand-like particles that I suspect is melted glass fibers and some small pieces of charcoal from the incineration. To the right you could see a small piece of the plastics with some bond wires still attached.
Now I only have to invent the pocket incinerator and my fortune is made... small time! :lol:
/Göran
Just as a proof of concept I took half a chip (I've already broken it in half to look for bond wires) and incinerated it. Then I put it in a beaker with water and a drop of detergent into a small ultrasonic cleaner (effect 70W). There was an instant cloud and I left it on for circa 20 seconds. Then I gently poured off the silty water and found that I hadn't incinerated long enough, there were half of the black plastic still left.
Another turn under the mini-torch and then back into the beaker and sonication.
The second time I managed to burn off almost all carbon. The end result was a tangle of wires, some copper wires from traces from the base PCB that stuck to the black top when I ripped it off and the rest golden bond wires. (picture 3) With it was some small white sand-like particles that I suspect is melted glass fibers and some small pieces of charcoal from the incineration. To the right you could see a small piece of the plastics with some bond wires still attached.
Now I only have to invent the pocket incinerator and my fortune is made... small time! :lol:
/Göran
I love the innovation that occurs on this forum.
May I also say that removing as much of the powders and plastics before trying to recover and refine the values is really important, I have rarely treated e scrap but have done large quantities of jewellers' sweeps and to ensure a decent recovery they usually need treating twice at least due to the amount of powder that shields the values from the acids and the amount of pregnant solution also trapped in the powders which is also difficult to fully remove even using large vacuum filter beds and many rinses.
Metals only been dissolved makes losses less likely as you can see if any metals or values remain.
May I also say that removing as much of the powders and plastics before trying to recover and refine the values is really important, I have rarely treated e scrap but have done large quantities of jewellers' sweeps and to ensure a decent recovery they usually need treating twice at least due to the amount of powder that shields the values from the acids and the amount of pregnant solution also trapped in the powders which is also difficult to fully remove even using large vacuum filter beds and many rinses.
Metals only been dissolved makes losses less likely as you can see if any metals or values remain.
patnor1011
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patnor1011
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samuel-a
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g_axelssong_axelsson said:
Can you share more info on exactly how you did it?
I have tried that before with no success - Wave table to separate pyrolized quads ?
Geo
Well-known member
Pat, that is called a "flip chip". If I understand right, the only gold content is in the legs if it's a plug in type. I dont know about any other PM inside. I incinerated 5 pounds of flip chip bases and never could recover any amount of gold from them.patnor1011 said:
Maybe the difference was in the plastic of the IC or the way I incinerated it. I think I described it quite detailed but if there are any details you feel I left out just ask.samuel-a said:
I did the incineration at a quite high temperature, some of the exposed bond wires melted at the end as I used a small hand held torch (based on a cigarette lighter) when I heated the chip. I heated it until the ashed chip was glowing cherry red for a while to be sure to get all carbon out of it. As the first picture shows I didn't incinerated long enough at first, but after a prolonged heating I got nearly all carbon out of the chip and then it easily turned into suspended clay during sonication.
In the thread you linked to you talk about both pyrolyzed and incinerated chips. Was there any difference in how they reacted on the sonication? After sonication of the incinerated chips what colour did they have? If your chips came up black you didn't incinerate them long enough.
If I get some time I'll try to do some more tests, but as the first snow came yesterday this season of refining is almost at an end for me.
/Göran
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