Gold inside chips (black, flatpacks - not CPU)

[jason_recliner]

I have finally started a small test run with RAM chips: Just 22 single and double sided SDRAM and DDR sticks carrying 130g of chips.

Using the coffee tin method with a few holes punched above the bottom and placed into the coals of a wood fire, only about half of them burned to white. I am now considering to make one of those soup-can furnaces. [Edit: I may mean forge. I'm not sure.]

This is not a question, but I'm not sure I entirely understand bond wires. Google / wiki don't say much. Inside my RAM it looks like the thick leg connecting wires, made of "whatever" spider into the centre and than have a short (1 - 1.5mm long) golden tip attached to them. They seem fairly firmly attached. But the main point is that they're quite thick and visible, whereas I was expecting something I could barely see.

With the large black bits picked out for reprocessing, I've had a go at panning anyway. I own one of those turbopans, with the spiralling ridges. They're great for processing large amounts of gravel quickly, but I'm not sure it's the best for small amounts with dust; with so many ridges in which to collect, a regular pan might be better. I am also not about to win any prizes for World's Greatest Panner*. Nevertheless I am pleased to start to see a little colour. But this is just fine dust, much finer than what I thought I could see on the legs.

Am I right in understanding that the silicon wafers with the shiny yellow appearance (one placed into shot) contain NO gold at all?


* I googled that term and found a pile of recipes for Indian cuisine.

 

[patnor1011]

I have finally started a small test run with RAM chips: Just 22 single and double sided SDRAM and DDR sticks carrying 130g of chips.

Using the coffee tin method with a few holes punched above the bottom and placed into the coals of a wood fire, only about half of them burned to white. I am now considering to make one of those soup-can furnaces. [Edit: I may mean forge. I'm not sure.]

This is not a question, but I'm not sure I entirely understand bond wires. Google / wiki don't say much. Inside my RAM it looks like the thick leg connecting wires, made of "whatever" spider into the centre and than have a short (1 - 1.5mm long) golden tip attached to them. They seem fairly firmly attached. But the main point is that they're quite thick and visible, whereas I was expecting something I could barely see.

That tip you see is where bonding wire is attached-soldered to pin.

With the large black bits picked out for reprocessing, I've had a go at panning anyway. I own one of those turbopans, with the spiralling ridges. They're great for processing large amounts of gravel quickly, but I'm not sure it's the best for small amounts with dust; with so many ridges in which to collect, a regular pan might be better. I am also not about to win any prizes for World's Greatest Panner*. Nevertheless I am pleased to start to see a little colour. But this is just fine dust, much finer than what I thought I could see on the legs.

It is dust or more wires it all depend on type of IC some do have bit longer wires some shorter. It all depend also on method of crushing of incinerated material. The more crushing the finer the gold wires - dust. If you incinerate them thoroughly to white dust more wires tend stay not broken. If you magnify that dust you will see it is actually wires. So small and thin they appear as dust. Also with 100+grams of IC you will see about 0.1 g of gold which is not much of dust to be seen. But you found it, you can see it and you now know what to look for.

Am I right in understanding that the silicon wafers with the shiny yellow appearance (one placed into shot) contain NO gold at all?
* I googled that term and found a pile of recipes for Indian cuisine.

Well they might. Mainly on sides where wires were attached to them. If you collect enough of them just give them bath in warm AR to be sure there is no more of gold on them. I do keep some with wires still attached, one day when I will get some small microscope I will do some cool pictures.

 

[jason_recliner]

Thanks Pat. As you say, if one can gather about a gazillion of them they'd be worth a soak. Otherwise... all that glitters is not gold.

 

[patnor1011]

You will be surprised how fast they add up. I just checked and I do have close to 2 kilograms of smallest one, those with 6-8 legs (3-4 on each side).
Just toss them to a bucket and in no time you will have it full. Then you can process them.

 

[g_axelsson]

Hi Jason, there is a lot of black stuff in the pan. Did you incinerate until the outside was white or were the chips white all the way through?

I always run the chips until the carbon is lost, any chips with black residues goes back again. With properly incinerated chips you could crush the chips between your fingers.

That tip you see is where bonding wire is attached-soldered to pin.

Actually, the wires are welded with heat, pressure and ultrasonic sound.
http://en.wikipedia.org/wiki/Wire_bonding

Göran

 

[maynman1751]

Very informative and interesting link. Thanks Goran. 8)

 

[jason_recliner]

Hi Jason, there is a lot of black stuff in the pan. Did you incinerate until the outside was white or were the chips white all the way through?

I always run the chips until the carbon is lost, any chips with black residues goes back again. With properly incinerated chips you could crush the chips between your fingers.

That tip you see is where bonding wire is attached-soldered to pin.

Actually, the wires are welded with heat, pressure and ultrasonic sound.
http://en.wikipedia.org/wiki/Wire_bonding

Göran

Yes mate. I know it's still very black. I just wanted to try while I had the Easter break. First thing I did was hold a single chip in the gas stove with pliers so I would have a target. It disintegrated like a Hollywood marriage.

So I filled a washing machine tub brazier with fire (wood, actually) and once the flame died down a bit, added the can to the coals. Some pretty flaming colours came from the chips, I stirred a little, and left it a couple of hours. About a third of them burned out to white - as soon as the flame was all gone it had lost adequate heat. Blowing air through a tube into/under the can didn't help much either.

I was going to try a little "chip-apartheid", but it was messy. I need something just a little hotter, or with better airflow, and will ultimately reprocess the lot.

 

[patnor1011]

I learned that less is sometimes more. That mean I try to incinerate only one layer of IC, they are white in no time. If you put more layers IC in the middle or on bottom will never get to that fluffy white stage when they are crumbling while you try to take them out.

 

[Smack]

Been working on chips the last few days, trying to get everything that needs incinerated done before it gets real warm out.
Not going to go over everything I've done as it's all been covered here, I just might do things a little different. If someone (not new) really want's to know the steps I took, ask and I will lay it out for you. The SST bucket is 7 gallon and has 43 lbs. of power ready for panning. The chips are all mixed black IC type off memory, mobo's and so on, gold is gold. Some of the weights are on the post "Show Your Work Area" for individual chip type but I added quite a bit to those amounts. I will say this about the first picture; The chips are pre-cooked in my friends wood burner prior to incineration to get rid of most of the smoke.

 

[gaurav_347]

i am really excited to see the outcome!

 

[MarcoP]

I'm impressed by your furnace! Is it gas or electric? (seems electric to me)

 

[mls26cwru]

Am I right in understanding that the silicon wafers with the shiny yellow appearance (one placed into shot) contain NO gold at all?

This is a wrong assumption...There will be some gold wire still attached to the chips even if they are ground up. The braze they use to attach the wire is mostly left on the Si chip along with some trace amounts of gold wire. it is most deffinitly worth processing this. I just processed a good amount of these Silcon chips and pulled out a fair amount of silver and more than enough gold to make it worth while.

 

[Smack]

It's electric Marco.

 

[gaurav_347]

any update on the outcome Smack?

 

[kurtak]

Hi Jason, there is a lot of black stuff in the pan. Did you incinerate until the outside was white or were the chips white all the way through?

I always run the chips until the carbon is lost, any chips with black residues goes back again. With properly incinerated chips you could crush the chips between your fingers.

Göran

You "do not" need to incinerate chips to complete ash in the first part of processing them - it is "only" important that the carbon gets reduced to white ash at the very end just before they go to being leached :!:

Here is a (copy/paste) post I posted on Kens forum - it was a reply to Geo posting a link to this video :arrow: https://www.youtube.com/watch?v=tP2_l7SnyVo

My post from Kens forum ------------------

That was a batch of my chips :mrgreen: please take note of how black the ash is - that is because that bucket of ash is actually about 75 - 80 percent carbon --- now you might thinking :shock: OMG he didn't do complete incineration to his chips - & you are right

complete incineration of chips - at this point in the processes "is not important" !!!

There are only two things that are important at this stage in the game

(1) is that they are at least "completely" carbonized - meaning that ALL the volatiles (epoxy resins) are burnt/roasted out so that they are nothing but carbon to the core (with a surface layer that has gone white ash)

As long as they are complete carbon to the core they will crush/mill as fine as you wish to mill (80 mesh & finer)

(2) crush/mill to "at least" minus 80 mesh --- that means 80 mesh is the largest that passes through the screen - but - 85 - 90 % is going to be MUCH smaller

Anything that does not go through the 80 mesh screen gets re-milled & re-sifted till all carbon has passed though the screen leaving only ground silicon & base metals (from legs)

The fine carbon is "plenty lite" & will wash off just fine when working on getting it down to your concentrates for processing

Once you have washed it down to your concentrate - that is when you want to do a final incineration to turn the carbon still in the concentrate to complete ash which you can then do a final wash on before processing

The only real concern for carbon is in the leaching process because the carbon will absorb & hold metal ions - meaning you will loose gold to this absorption if there is carbon in the leaching process

Other then that carbon is not a problem during the washing/concentrating part of the process !!!

I do about 200 - 300 pounds of "mixed chips" per year (in 30 - 50 pound batches) & have no problem doing it this way & get recovery of .5 grams/lb (if there is a lot of proms in the mix) to as high .648 grams/lb (not a lot of proms)

When I say mixed chips that is RAM, quads & proms - no BGA's - BGA's are always processed alone as BGA's

Kurt

 

[MarcoP]

Soon or later it will all sink into my head. This thread is being very helpful while in getting ready to incinerate about 17Kg (~35lb) of RAM chips only, ~1Kg of mobile phones BGA and one more of MB's BGA. I've tested incineration with small lots of EPROMs like chips and I didn't like it so far but from the above post seems I'm on the right path.

While reading the stock is growing and now my only issue is how to process the big lot of RAM chips :roll:

 

[patnor1011]

I was cleaning my garage and found Fresnel lens I bought some time ago. After while I was looking at my stockpot wondering I need to evaporate about 80% of it as I put in even wash water and it somehow grew in size considerably. I also just finished processing 5,1 BGA s/n bridge for one friend and I again added some water and spent AR in it.
Then I thought I may give Fresnel a shot, sun is a free energy to use. During all time I was doing it (about 30 minutes - evening sun is not too great to work with) solution was evaporating with visible vapour. Sides of bucket or liquid as whole did not heated up even that focal point was making small point of it on surface boiling with visible small bubbles forming. I will give it a try again tomorrow when sun will be highest. I used very crude setup but if this is viable I may construct something for future use.
I uploaded short cell phone video on youtube just to give you all an idea what I was doing.

https://www.youtube.com/watch?v=pt-9vT0vTtw

Oh and that 5.1 BGA (very sloppy harvesting with big blobs of solder and sometimes even screws and capacitors lodged in that solder) yield was 26.25g (5.147g/kg).
Picture of gold with melting dish (clean with hint of purple / twice refined should be good quality, only ran out of gas at final stage but it was fully melted anyway).

 

[g_axelsson]

Fun experiment, but you should paint the bucket black and just put some mirrors around it. The energy collected by the fresnel lens can't be more than what sunlight passes through the lens and then is absorbed in the liquid. The bucket in itself would collect as much energy if the area was the same and it was black to better absorb the heat.A black pipe above it could be used as a chimney and suck the air from the bucket, that way you would increase evaporation by removing the heavy water vapors that forms an invisible cover.

Göran

 

[Smack]

any update on the outcome Smack?

Not yet, finished incineration of N/S bridge today. I think I'm done with incineration now. Have more ball milling to do, get more Nitric, dentist, vet for my sick pooch, the list goes on.

Patnor, that can be tricky with the Fresnel lens and plastic because of the sun moving across the sky, don't leave it unattended. A large glass container would be better I would think.

 

[patnor1011]

I actually made black spot on that bucket as I was adjusting focus. I plan to do experiment with measurable glass pyrex jug and take note of time. I also plan to get bigger lens. I remember I tried incinerating IC with that lens but focus point is small it will take a lot of time to adjust it to single small IC's. There was also issue with smoke. So evaporating solution may be better idea than incinerating IC unless you own monster size Fresnel lens. :lol:
Short exposure on focal point may be good and free way for harvesting BGA out of motherboard. It may actually be faster than hot air gun.