First time processing mmx black fibre

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archeonist

Well-known member
Joined
Jun 27, 2012
Messages
286
Today started with processing black fibre cpu's. After I removed the epoxy and caps, I will give them a soak in HCl. I guess the pins will fall off, so I can process them separately. The rest of the chips go straight into AR.
I will keep you guys informed about the progress.
 

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Straight into AR or incinerated first to recover bond wires inside the epoxy?

Göran
 
Goran, the black epoxy centers I smashed out I will incinerate along with a bunch of flatpacks.
 
Soaking now in hydrochloric, no heat yet, a lot of H2 formation so solder is going into solution.
 

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Solution turning green, indication Ni in solution, pins are falling off.... Uhm, well hopefully they fall off soon :?
 

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Hmm.., now this is strange, why do most of my pins have a copperish color? I boiled in HCl for a few hours, only a few pins had come off. Is it ok to go to AR with the pins?
Also the top epoxy layer is coming off. Revealing copper plating underneath, that I did not want to happen.. more basemetal will go in solution..

In the picture the cpu are soaked in fresh tap water.
 

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Here you see what I mean. I can scratch the top epoxy layer off revealing copper underneath. Did not want that :evil:
 

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Firstly, you should use some thermal buffer between your hotplate and the beaker, for example sand, to avoid creating thermal stress that can break your beaker.
Secondly a catch basin below is good to have when a beaker breaks. Maybe you have that but I couldn't see it on the pictures.

You obviously have dissolved some copper, creating a weak copper chloride leach. Some of the copper have cemented out on the kovar pins and you see that as a pink copper coating.
The pins will not fall off until the pins are totally dissolved through, they sit in a hole going through the fiber board and not flat on the bottom as later chips have.

It looks like the copper chloride have penetrated under the top solder mask, not much to do about it I guess.

Göran
 
Goran, I do use a thermal buffer and catch bassin. For the picture I just shot the glass on a hotplate.
What should I do? Carry on dissolve pins untill they fall off, or throw everything in AR?

I agree copper has cemented out on the pins. The kovar is now in contact with the acid. Copper ions are reduced on the surface of the gold pins to copper atoms. The electrons are delivered by the kovar that is going into solution, for instance iron or nickel.
 
I have sucessfuly processed Black MMX processors this way:
- removing copper hearsinks, all SMD components and black chips which I processed like all the other IC chips
-simmer boiling in a 16-18% HCl for about 2 hours, all of the tin dissolved.
- decanting tin bearing HCl solution, washed beaker with water several times
-Added fresh HCl and adding KNO3 until all of the metals dissolves.
-watch out, when the reaction is nearly ended it will be vigorous reaction, you will need much bigger beaker filled maximum to 1/3 of the volume.
-after that, regular denoxing, filtering and gold dropping

I had some losses when processing these, but even with the losses I had 1.5g of gold per kg or 0.03 per piece of this kind of processors, including black chips with dies.

I hope this helped a bit.
 
I did them in straight AR, no HCl before. Cores incinerated and crushed then AR too. Pretty fast but as others said be aware that they tend to foam in hot AR so use big beaker.
 
g_axelsson said:
Romix said:
Can't get pins off on this.
How did you try to remove them?

Göran

Heating with lighter, that goes to the temperature of gold melting point.
Cpu began to melt, but pins didn't came off.
 
If you read my description of the construction of these CPU:s above you will understand why the pins doesn't fall off.

My guess is that a third of the gold is contained in the pins that sticks out, a third is dissolved in the solder that holds the pins and a third is in the bond wires inside the epoxy. I suspected that there could be some gold dissolved in the solder that holds the heat spreader, but so far that part seems to be very low in gold content.

Göran
 
Tzoax said:
I have sucessfuly processed Black MMX processors this way:
- removing copper hearsinks, all SMD components and black chips which I processed like all the other IC chips
-simmer boiling in a 16-18% HCl for about 2 hours, all of the tin dissolved.
- decanting tin bearing HCl solution, washed beaker with water several times
-Added fresh HCl and adding KNO3 until all of the metals dissolves.
-watch out, when the reaction is nearly ended it will be vigorous reaction, you will need much bigger beaker filled maximum to 1/3 of the volume.
-after that, regular denoxing, filtering and gold dropping

I had some losses when processing these, but even with the losses I had 1.5g of gold per kg or 0.03 per piece of this kind of processors, including black chips with dies.

I hope this helped a bit.
Did you wash away the black sludge that is produced when the tin dissolves? It contains gold.

I have only done one test run to refine a kilo (53 CPU:s) and I have so far recovered 3.3g. I think I have a few tenth of a gram left to recover, judging from the color of the second leach of the solids. I'm doing a second leach since I suspect that I ran out of nitric, newbie mistake, adding too little nitric acid. :mrgreen:

I also have to recover the gold from the dilute washing water I used on the CPU:s after dissolving the pins. The water was turbid even after filtering, but after standing for a while a fine black sediment appeared at the bottom of the beaker.

Göran
 
:lol:
Newbies add too much nitric, and now newbies can add too little.... Whats a newbie to do?!?
:lol:
I'd rather be the underestimating newbie than the overdosing one though... I loath getting rid of excess nitric, and it's such a shame to waste such expensive acid!
 
Yeah, I was so surprised when the sulfamic didn't react and then the gold dropped with SMB really nice....
... my bad.

:mrgreen:

I was going to do a second leach anyhow, just to verify that I had gotten all the gold. Looks like I missed a minor part. Leaching as we are speaking. :D

Göran
 
g_axelsson said:
Tzoax said:
I have sucessfuly processed Black MMX processors this way:
- removing copper hearsinks, all SMD components and black chips which I processed like all the other IC chips
-simmer boiling in a 16-18% HCl for about 2 hours, all of the tin dissolved.
- decanting tin bearing HCl solution, washed beaker with water several times
-Added fresh HCl and adding KNO3 until all of the metals dissolves.
-watch out, when the reaction is nearly ended it will be vigorous reaction, you will need much bigger beaker filled maximum to 1/3 of the volume.
-after that, regular denoxing, filtering and gold dropping

I had some losses when processing these, but even with the losses I had 1.5g of gold per kg or 0.03 per piece of this kind of processors, including black chips with dies.

I hope this helped a bit.
Did you wash away the black sludge that is produced when the tin dissolves? It contains gold.

I have only done one test run to refine a kilo (53 CPU:s) and I have so far recovered 3.3g. I think I have a few tenth of a gram left to recover, judging from the color of the second leach of the solids. I'm doing a second leach since I suspect that I ran out of nitric, newbie mistake, adding too little nitric acid. :mrgreen:

I also have to recover the gold from the dilute washing water I used on the CPU:s after dissolving the pins. The water was turbid even after filtering, but after standing for a while a fine black sediment appeared at the bottom of the beaker.

Göran

I heated the beaker with water to about 70 degrees Celsius. The solution had milky white color. I mixed the solution, watching sediment forming. After about 10 seconds all of the sediment appeared to be settled. I decanted it, and repeated this step 2 more times. At final washing water was clear.

So i am not sure if i decanted some of the gold if it was there, it all depences how small (light) particles of gold was there(if any).
 
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