Non-Chemical To grind or not to grind....

[youngleo]

Steve,

Here is the process. I am not sure how repeatable it will be for you. It is not exactly home brew, but I think that you may be able to speed up the process that you already use with a sand/lead filled pipe or something. The trick is in the ball bearings. We used a 3 ton Denison press and made a ram and cup with some found materials around my shop. The reason that we used the Denison is because it is fast. It will cycle completely in around a second and a half. I think that the pictures explain it all. The balls make more efficient crush points and act more like a mortar and pestle. Notice that the ram is offset. We spin the cup every cycle and after about 5 or ten cycles dig around in the cup with a screwdriver as a poker. We ran it for 2 minutes and after we used a magnet to pull the metal out, the middle pictures are the result. This can be screened and reground as needed. (actually the earlier pictures with the chips and balls are staged, I forgot to take the pictures before I cycled the press so I had to improvise).

youngleo

 

[lazersteve]

Leo,

Thanks for the photos.

Have you tried panning the dust to see if you've got any hair fine gold wires in the dust?

Steve

 

[youngleo]

I have not, I assumed that since gold is so soft, they would be pulverized into the dust. In fact, that is one of my concerns with this process. I was thinking that the gold may stick to the steel cup and ram. I figured that I would move on to a gold recovery straight from this step. I just have no idea what is best suited for this type of medium. Still reading through the forum on that one.

 

[lazersteve]

HCl-Cl is cheap and works really well on finely divided gold.

You would be well served to remove the base metals first.

Steve

 

[youngleo]

From what I have read, it seems like the gold is vulnerable to the chemical reactions that dissolve base metals. A few strong acids will work but I am not sure here on the effectiveness-to-possible-gold-loss ratio and what to use? If I end up with gold in the base metal solution, will reducing the pH of the strong acids and precipitating the gold be effective? What about with solder and other base metals dissolved in the mix? That is not even really the worst part though. I read some fairly discouraging posts that speak of newbies ending up with 10 different slurries of god-knows-what metal oxides and poison soups. There has got to be some sort of better way? Perhaps I am just paranoid. I just really want to do it right the first time around though. This is different than fingers/AP/rinse/HCl-Cl/SMB methodology. Isn't it?

Leo

 

[goldsilverpro]

On these particular types of side-braze parts, of which I've refined tons of, literally, it's certainly not necessary or even desirable to grind them up. I think you have complicated the job and have made getting all of the gold much more difficult by grinding. In this powder form, it is much more difficult to leach, filter, and rinse than it would be if the parts were left somewhat whole. It's very easy to get incomplete dissolving and to trap dissolved values in that powder. It is also hard to know when all of the gold has been dissolved, since you have eliminated the possibility of visual inspection. You have made a fairly simple refining job much more difficult by grinding, in my estimation.

On those particular parts, I guarantee that there is zero gold or other PMs trapped in between the ceramic layers. If you remove the lid, you will be able to visually see 100% of the gold, with the exception of what's under the chip. Intel, and other companies that make the chips, do not make the packages. They buy the packages from a package manufacturer, such as Kyocera. Intel then brazes the chip to the pad, attaches the chip to the inside fingers with gold or aluminum bonding wires, and brazes the lid on. There is no way that any of the bonding wires will be trapped in the ceramic - that is, unless you grind up the parts.

There are 2 basic good ways to properly refine these parts and assure that 100% of the gold has been recovered.

(1) Leach in hot 50/50 nitric until all of the base metals (legs, lid, and the silver solder holding the legs on) are dissolved. Dissolve what remains in hot aqua regia (I use the 2 acids separately and don't use excess nitric) until the chip is loose and will slide around freely on the pad. At this point, 100% of the gold will be in the aqua regia. It is possible to do all this in one long day. I much prefer this method - the base metals are eliminated and there's much less aqua regia to deal with.

(2) Dissolve everything (gold and base metals) in aqua regia. Here again, make every attempt to avoid using excess nitric acid.

In both cases, if you don't use an excess of nitric in the aqua regia, the gold will drop with SMB, SO2, or sodium sulfite. If an excess was used, SO2 will still work.

Dissolving the gold under the chip is the bottleneck in both methods. This can be done faster if the part (actually, the chip) is first broken into just a few whole pieces with a hammer or a mortar and pestle.

If you want to eliminate the possibility of losing any gold, don't grind these parts. For other types of CPUs, the only ones that would require grinding are the ones that Steve mentioned, where fiber, plastic, or epoxy are part of the package.

For early black MMX and Celeron, PII's and PIII's (the slotted and fiber types), I'm 100% certain grinding will increase the yield because these types have the black epoxy area in the bottom center of the cpu has a myriad of hair fine gold wires in it

 

[gold4mike]

I'm accumulating a pretty good pile, 100 or so pieces, of packages that have a small square window in the center. Some obviously contain gold, as you can see it through the window. Most, however, look silver through the window and I was wondering if GSP or anyone else knows what (if any) PM's are contained in those packages. Looking at the page that Chris posted a link to, these would either be CERDIPS or Side Braze Packages.

 

[goldsilverpro]

The CERDIPS are a metal (almost always magnetic Kovar) lead frame sandwiched between two layers of almost black ceramic. In the 80s, at least, they came in different sizes and were found on most any board you saw. The lead frame and ceramics are held together with glass. The lead frame consists of the inside bonding fingers and the protruding bent down legs. Usually, the only gold plating on the lead frame is a spot-plated area that only covers the tips of the inside fingers, so that they will accept a wire bond from the chip. The bottom layer of ceramic has a small gold coated square (or, rectangular) area in the center - where the chip will be mounted. The top layer has a large square or rectangular depression in it. Look at the photo.

The perfect simple refining cycle. These can simply be taken apart by heating them to about 700-800F and then quenching them in water - the glass shatters. Tumble them, by themselves, in a cement mixer and they fall apart. Separate the metal with a magnet. Now you have ceramic with a small gold pad on it and Kovar with about 4 or 5 cents of gold on it. About the only way to make money on these is to do them in volume and use a cyanide/H2O2 stripper in, say, a cement mixer. Also, the stripped kovar is 29%Ni and 17%Co, so the base metal has scrap value. After stripping and rinsing the lead frames, you can rinse them with a weak NaOH/bleach solution to kill any traces of cyanide on the metal. This makes it a lot safer for the scrap dealer. Money can be made on these.

PLASTIC DIPS are black, very common and look very much like CerDips. Besides being plastic, the only other difference is that the gold plated pad where the chip is mounted is the center part of the lead frame instead of an area screened onto the ceramic. Sometimes, the legs will be gold-plated also. Those are the ones most worth processing, but they're getting rarer and rarer.

Both Ceramic and, especially, Plastic DIPs can be made with other things besides gold. Some use silver plating and some use epoxy to hold the chip on. You have to split them open and see what you have.

SIDE_BRAZE packages are what the guy ground up. They are worth 20 to 50 times more than CERDIPs. I've covered how these are made and how to process them many times on the forum.

EDIT: The info I gave for SIDE_BRAZE packages above assumes that everything is gold plated. There are many SIDE_BRAZE packages that have non-gold plated lids and/or legs. These look identical to the ones that were ground up except that the lids and/or legs aren't gold plated. Also, I ran some parts for Intel that used a non-gold, nickel base braze to attach the non-gold plated lid. These things can lower the value considerably. Every one of these that I've seen with a gold lid uses gold/tin braze for the lid. If the lid isn't gold-plated, gold braze is not used.

 

[gold4mike]

Thank you for the very thorough and very fast reply. I believe what I have are side braze packages. I'll crack a few open an see what I find inside.

 

[goldsilverpro]

gold4mike,

If yours don't look like the ones that were ground up, with gold plating or not, you have something else.

 

[g_axelsson]

Digging up another old thread...

Why Oh Why would they put gold between the ceramic sections in these particular parts? Besides the added difficulties and much greater costs of using gold here, the Mo/Mn works great and it's cheap. The last time I ran drum loads of CPU packages was in about 2003. At that time, I don't think that any CPU package had any gold encased in the ceramic. I never saw one, at least, and I think I saw 99% of what was out there.

There are a number of reasons to have gold or silver in the ceramic capsule. In recent years the number of connectors on a chip have risen sharply and to get all those tracks into the chip you have to make narrower tracks. The Mo, Mo-Mn and W-tracks have too high resistance so copper, gold, silver and even pgm:s in different alloys have been used. At least with the advance in LTCC (Low Temperature Cofired Ceramics) it is now possible to build systems in hybrid packages with traces of gold and other precious metals.
Some areas where hybrid modules are used in is in mobile phones, high frequency radio and radar equipment and in high end computers.

Reference : http://www.ltcc-consulting.com/LTCC_technology_materials

/Göran

 

[dtectr]

Digging up another old thread...

Why Oh Why would they put gold between the ceramic sections in these particular parts? Besides the added difficulties and much greater costs of using gold here, the Mo/Mn works great and it's cheap. The last time I ran drum loads of CPU packages was in about 2003. At that time, I don't think that any CPU package had any gold encased in the ceramic. I never saw one, at least, and I think I saw 99% of what was out there.

There are a number of reasons to have gold or silver in the ceramic capsule. In recent years the number of connectors on a chip have risen sharply and to get all those tracks into the chip you have to make narrower tracks. The Mo, Mo-Mn and W-tracks have too high resistance so copper, gold, silver and even pgm:s in different alloys have been used. At least with the advance in LTCC (Low Temperature Cofired Ceramics) it is now possible to build systems in hybrid packages with traces of gold and other precious metals.
Some areas where hybrid modules are used in is in mobile phones, high frequency radio and radar equipment and in high end computers.

Reference : http://www.ltcc-consulting.com/LTCC_technology_materials

/Göran

i have taken some photos of my (extremely limited, singular) experience with ceramic & fiberglass-layered chips. I will post when all are developed after excursion to WILDERNESS" ("tweeet-tweeet" (that's birds);"brrr-ip, brrr-ip" (that's frogs); "_____" (that's no people"). there does seem to be a fair quantity of gold in the ceramic on some, but can't say which till I get photos developed.
jordan

 

[lazersteve]

Most of the Pentium and older genre ceramic cpus are not going to have the precious metals traces inside the ceramic substrate. As Goran points out, this is a recent trend brought about by extreme miniaturization requirements. Back in the day this was not the case.

Steve

 

[hfywc]

there's a way to settle this....

process the the ics or cpus first without breaking/grinding to remove every metal visible. then grind and leach with ar to see if there are still gold to be extracted.
i would love to try this but i have no access to a grinding machine.

would be nice if it can be done by types of cpu just to find out which ones contains gold.

just my thoughts.

alan

 

[Bellien]

I noticed most of the references in the thread where to CPUs, I've seen what looked like very thin fibres of gold on the edges of several broken IC chips. I stuck one under a microscope to see what you think.

In the first picture is the bottom of the chip which was separated from its fibre base, the yellow/orange objects are coated gold foils. The wires appear to penetrate down through the ceramic to connect with these conductors.

The middle picture is the broken chip with the wires general location indicated by the pencil lines.

The microscope shot is at 100X and taken with a blackberry - the quality suffered a lot.

The depth is lost but the wires are roughly 1/4 of the way through the ceramic, the longer of them is the only one visible to my naked eye, and only just.

As far as I can tell the top part of the chip is ceramic, and the wires are embedded in the ceramic. The chip is out of a modem.

Does this fit with general experience?

 

[NoIdea]

Hello All - Just gunna throw in my two cents worth. Due to my lack of finance i always look outside the square, I put my CPU's in a 500ml tin can, making sure the pins and metal on the CPU's are not touching the can sides (eliminate diffusion). Placing another smaller can with a larger diameter so it can sit on top, making a lid. Then put this into our fire place to cook. Basically things tend to fall off, even the silicon waffer, which i read in another clip on here that you can get $5NZ each. After cooling, the bits that fall off are remover and the rest of the CPU gets put into an old CO2 canister (Approx. 8cm inside dia, 30cm long and 3 to 4mm thick) with it's top cut off and armed with a 4cm diameter steel rod and hammer i hammer the ba-gee-biz out of it. Makes alot of noise but it works.

Deano

 

[Macgiver]

A simple ball mill can be made from a Harbor Freight cement mixer found on sale for $99. Flatten out the paddles for less angle of attack, the get some used large (1 to 3 inch in size and 5 to 15 in count) ball bearings from a machine shop, create a cover for the front of HTPE or use thick plastic 6mm or better, affixed with a large heavy rubber band. Fill the mixer about 1/3 full, close the cover, turn it on and let it run for a few hours. Sift and re run any remaining larger pieces. ALWAYS wear a mask and protective goggles to avoid ingesting dust.

CW