Sim Cards

[bswartzwelder]

I had about 1400 (give or take) SIM cards and decided to try to process them. I pried/cut the foil contacts and the microchips from the plastic cards.

Next, I mixed up some AR and dropped the SIM card modules into it. There was quite a reaction. Finally, after everything settled down I stuck a Q-tip into the dark green almost black liquid. I dropped a drop of stannous chloride onto it and nothing. It did not turn dark like there was any gold in the liquid at all.

A day later, I filtered all the remnants from the SIM cards out and noticed a metallic coating on the inside of the beaker. The coating appeared to be a mosaic pattern. The only conclusion I could come to was that the gold had dissolved and then the copper and any other metals underneath dissolved. Then they somehow deposited onto the inside of the glass beaker. The fact that there is metal on the inside of the beaker and no traces of gold in the solution would seem to support this. Has anyone else seen anything like this?

My next plan of action is to mix a little new AR and use it to wash the inside of the beaker to see if it will dissolve the metallic coating and then test that with stannous.

I have also come across quite a few more SIM card modules and don't want to make the same mistake. Should I give them the AP treatment and try to recover the foils that way first? Open to suggestions.

While I'm on the subject, I have ordered a cast iron pot and intend to incinerate what's left of the SIM card modules after they're dunk in AR. Curious to see if there's any appreciable amount of gold in the microchips.

Thanks,
Bert

 

[g_axelsson]

Did you check for bond wires? If you just dumped the cards in AR the acid can't reach the bond wires that are covered by a protective plastic.
I have a small lot of SIM cards and when I check them in the microscope everyone has six small golden bond wires going between the card and the chip on the back side.

Just as with processing fingers, the best way is to remove the base metals before dissolving the gold. When throwing it all in AR you only made a big mess. Did you remove excess nitric before testing? If you have too much nitric ions in the solution the stannous test could give a false negative as the colloidal gold is redissolved.

In a small batch it's easiest and fastest to use nitric to dissolve the copper but more expensive. In a larger batch I would use the copper chloride process (AP) to dissolve the copper.

My suggestion : (never tried this yet practically)
Small test batch :
- Incinerate the SIM cards to free the bond wires
- Dissolve the copper with nitric acid
- Decant the copper nitrate liquid via filter to catch fine gold, wash with water until almost colorless.
- Add HCl and a tiny (few drops) of nitric to dissolve the gold. The remaining nitric from the copper leach will dissolve most of the gold when you add HCl.
- Decant / filter / wash to get the gold chloride from the incinerated cards (glass fiber, chips, ash)
- precipitate gold with your preferred method

Big production batch
- Leach SIM cards with copper chloride leach to get rid of base metals.
- Separate the foils from the plastic cards
- Incinerate the cards to release bond wires
- Wash away ash. There's no gold foils here now that makes panning problematic. You would still have fibers and chips mixed with the bond wires. Getting the ash away makes the solution easier to filter.
- Wash the bond wires and fibers with some nitric, removes any remaining copper
- Dissolve gold with AR (foils and bond wires in separate batches)
- Filter off the gold chloride and precipitate as preferred (Keep separate if you want data on how much gold is in the foils and wires)

.. but this is only how I'm planning to do my scrap. Try it if you think it sounds wise or criticize me if you think that I'm wrong.

Recommended reading:
Processing sim cards
Processing smart cards, sim cards
Both links contains yield numbers

Göran

 

[kurtak]

Bert

Ether one of Goran's methods will work - personally if I ever had a large amount of SIMs to process & was going to use a leaching method I would go with the first process (I get my nitric really cheap)

the coating you see on the inside of your beaker is most likely at least some of your gold - also the plastic used in SIMs is some what porous so some could be tied up in or on the plastic (AuCL absorbed into the plastic &/or the same effect you see coating the beaker also coating the plastic)

Should that be the case - that gold can be recovered by incinerating & leaching the ash - which you want to do to recover the gold bonding wires anyway

Personally (& this is another option) what I do (because I never have enough SIMs to justify doing a batch in & of them selves) is I incinerate them along with my filter papers, anode bags, & other low grade stuff - smelt the metals out of the ash with silver &/or copper as a collector metal - then go to chem processing the metals

first nitric to recover Ag/Pd & some Pt --- then AR to recover Au/Pt & any remaining Pd (other steps required with multiple metals involved including multiple BMs)

So if you are set up to do smelting that is another method to consider - your smelted metals are for the most part going to be gold, copper (already existing) & silver (some added as collector) then dissolve Cu & Ag with nitric leaving your gold powders - a lot like inquarted karat scrap

Kurt

edit to correct - then AR to recover Au/Pt & any remaining Pd --- instead of Ag/Pt which I first wrote

 

[bswartzwelder]

No. I never checked for bond wires. I was pretty sure the AR could not get to them, so I was planning to incinerate them at a later time. I did pull the modules off the plastic sim card they were mounted to.

"Everyone has six small golden bonding wires going between the card and the chip on the back side." WOW. I suspected the bond wires between the foils (contacts) and the chip might not be gold, but wires inside the chip would be gold. I mis-read Palladiums post about processing SIM Cards. He said to put them into a bucket with holes in it like in the AP process, but I didn't see where he said to process them with AP.

I am expecting a package which will be only the sim card modules and not have the entire plastic card. There should be over 6000 in that package and I wanted to use this smaller batch to iron out any bugs in my methodology. Glad I did. Better to screw up a small batch rather than a larger one. I suspect the foils will still be connected to some kind of a plastic piece, but not have the extra plastic. Could be the modules were cut off with shears in which case I will still have an abundance of plastic to deal with. I'll just wait and see.

I didn't remove excess nitric before the first testing, but did add sulfamic acid before subsequent testings. At all times, the tests showed no gold. My stannous if from a fresh batch and I did test it with gold chloride before testing the solution in question. That's one thing I learned from the forum and always follow through even if I used the stannous only a day before and it tested good. Better to be safe than sorry.

I have a brand new 5000ml beaker and I'm not sure if I want to use that for a copper chloride leach on all the modules when they arrive, or just throw them all into my 5 gallon AP bucket for processing.

Since the mistake I made, I have been thinking quite a bit about how to tackle this issue in the future, so I greatly appreciate your input. Right now, I'll just plan on using AP to release the foils and then process them in AR. Put everything that's left in a cast iron pot and incinerate to a white powdery ash. I have a blue bowl for gold panning and a blue spiral gold panning bowl which would be my preferred choice for wires this tiny.

Again, thanks for the input.

 

[yar]

While I'm on the subject, I have ordered a cast iron pot and intend to incinerate what's left of the SIM card modules after they're dunk in AR. Curious to see if there's any appreciable amount of gold in the microchips.

I believe stainless steel is preferred over cast iron when incinerating.

 

[Harold_V]

Put everything that's left in a cast iron pot and incinerate to a white powdery ash.

Not a good idea. Cast iron has way too much mass to heat, although it would be to advantage once hot. However, cast iron is subject to thermal shock, for lack of a better description. Uneven heating can be the cause of cracking. Stick with stainless. It's readily available, and inexpensive when purchased as old fry pans from thrift stores.

Harold

 

[kurtak]

yup - stainless is a much better choice

Kurt

 

[bswartzwelder]

OK then. My wife will be getting a new cast iron stock pot for Christmas and I'll be getting an old stainless steel pot at the thrift store or flea market wherever I see it first.

Thanks for the heads up.

 

[Harold_V]

OK then. My wife will be getting a new cast iron stock pot for Christmas and I'll be getting an old stainless steel pot at the thrift store or flea market wherever I see it first.

Thanks for the heads up.

I couldn't help but notice your use of the word pot. Be careful to use fry pans, not pots. The incineration process relies on oxygen. The deeper the vessel, the less chance the contents have of being exposed to oxygen, as the gassing can create an atmosphere void of free oxygen. The shallower the pan, the better.

Harold

 

[Palladium]

I never used the ap process to do sim cards. I just used some of the same type processes with the equipment, but not the chemicals. Easiest way i found was naoh to get rid of the glue and free the plastic from the chip to get to the bonding wires. Incineration works, but leaves to much ash and mess for me. This way just seems cleaner and easier for me anyways.

 

[Anonymous]

I never bother with recovery. I test a couple in AR complete to make sure the plastic doesn't dissolve then I chuck the lot in. It takes the copper up with the gold so I know I have to deal with that but it leaves behind the part containing the bonding wires quite nicely for other processing. The yields are quite poor on these.

 

[kurtak]

I never bother with recovery. I test a couple in AR complete to make sure the plastic doesn't dissolve then I chuck the lot in. It takes the copper up with the gold so I know I have to deal with that but it leaves behind the part containing the bonding wires quite nicely for other processing. The yields are quite poor on these.

Maybe I am missing something here but I don't quit get the concept on running these in 2 different process --- one to recover the gold from the foils - then another one to recover the gold from the bonding wires ?

to recover the bonding wire gold you need to incinerate - so why not just incinerate & then ether leach the ash or smelt with silver the as a collector metal, dissolve the silver & let the gold settle - much the same process as inquarting

personally I don't ever get enough of them to process on there own so I incinerate them with may filters & anode bags etc. then smelt the ash with silver as a collector & then do the chem work on the metal recovered from the smelt --- even if I ever got a large amount of them (enough to process on there own) I would most likely go with the incinerate/smelt process - it recovers both the foils & wires in the same process

if you incinerate just the chip its not a lot of ash

 

[bswartzwelder]

I had a small batch which I just dumped into AR. It was a mistake because I still had the copper underneath to deal with.

A second batch (over 6000) which consisted of only the modules and not the entire card was going to be my primary focus. They did have adhesive on the back side. I put some in denatured alcohol with little effect, put some in mineral spirits with no effect, and some in lacquer thinner. The lacquer thinner turned a dark orange color, but did not get rid of all the adhesive. I took all of them and put them into several bottles with a lot of dishwashing soap and water. Capped the bottles and shook the crap out of them. Dumped off the water, added fresh water and shook them again. Repeated the process until all the soap had gone down the drain.

Then I put all of them into a deep stainless steel frying pan and started the process over using the method outlined by Palladium in the Tutorial section of the forum. The hot NaOH made a difference. It turned the adhesive from a sticky mess into a rubbery mess which is still attached to the boards. It also made the tiny drop of clear plastic holding the microchip to the back of the card disappear. The microchip may still be in the bottom of the wash bucket, but and bonding wires are most likely lost forever. I still have about 6000 of the little pieces with the contacts and gold plating on one side. Strange, but any exposed metal on the back side also has gold plating on it. However, to get rid of the old adhesive (now rubbery), I must rub it off.

I think unless I get SIM cards for free in the future, I'll just sell them to some other lucky person. I suppose I could just incinerate everything, but I don't know what effect that might have on the foils.

 

[Anonymous]

To be honest Kurt I use two processes because I have never been able to see the point of mixing up visible gold that's easy to recover with a pile of ash.

Faffing about recovering gold from ash isn't one of my favorite past times at the best of times so if I can avoid it with easy to recover gold I do. The copper under the gold really isn't a problem with these.

Edit: for typo

 

[Palladium]

You didn't use a high enough concentration of naoh or you didn't heat them long enough. It will break the glue and epoxy down into black powdery stuff. The chips will seperate. Dump them into a strainer bucket with holes and shake. All the small chips and wires will fall into the bucket below and after a couple of minutes its settled and you can tip the bucket and pour out the rinse leaving nothing but small chips and bonding wire that are easy to process with ar.

 

[lanfear]

I have seen a youtube video from the philipphines of guy that used xxxxxx and xxxxxxc to dissolve the epoxy layer on P2 chips. Just a thought.
This has never been an option to me because of the prices on xxxx an xxxxxx in my country. So I have no personal experience. This mix could also be dangerous i would think. These philippihne guys don't always put safety first.



edited for safety

Jon

 

[g_axelsson]

I have seen a youtube video from the philipphines of guy that used xxxxxxx and xxxxxxx to dissolve the epoxy layer on P2 chips. Just a thought.
This has never been an option to me because of the prices on nitric an sulfuric in my country. So I have no personal experience. This mix could also be dangerous i would think. These philippihne guys don't always put safety first.

Jon

This is one of the reasons we don't recommend people to learn refining from youtube.

It is much easier, cheaper and above all safer to incinerate. Anything that can easily dissolve plastic will eat the flesh of your hand with vengeance. This process has no value for a refiner and is not usually discussed on the forum because of the dangers associated with it.

Göran

 

[kurtak]

You didn't use a high enough concentration of naoh or you didn't heat them long enough. It will break the glue and epoxy down into black powdery stuff. The chips will seperate. Dump them into a strainer bucket with holes and shake. All the small chips and wires will fall into the bucket below and after a couple of minutes its settled and you can tip the bucket and pour out the rinse leaving nothing but small chips and bonding wire that are easy to process with ar.

Interesting process you came up with Palladium - as they say there's more then one way to skin a cat :mrgreen:

I personally have become a real fan of incinerate/smelt - but then again I have two furnace's - the big one takes a #40 crucible & the small one a #4 crucible

I don't leach anything from ash any more & haven't for a couple years now

I really like being able to do my chem work on whole metals (poured to shot) instead of trying to leach it from some other media that's a pain to get all your chem washed & recovered back out of &/or even extra chem work to get to the metals your after

I realize not everyone is set up to smelt but it sure has made my life of refining easier

Kurt

 

[lanfear]

I have seen a youtube video from the philipphines of guy that used xxxxxxx and xxxxxxx to dissolve the epoxy layer on P2 chips. Just a thought.
This has never been an option to me because of the prices on xxxxxxx an xxxxxx in my country. So I have no personal experience. This mix could also be dangerous i would think. These philippihne guys don't always put safety first.

Jon

This is one of the reasons we don't recommend people to learn refining from youtube.

It is much easier, cheaper and above all safer to incinerate. Anything that can easily dissolve plastic will eat the flesh of your hand with vengeance. This process has no value for a refiner and is not usually discussed on the forum because of the dangers associated with it.

Göran

Thank for the correction Gøran. I knew the other process of oxydizing the sulfuric was bad and I had my suspicions about this one. I don't learn off youtube I just can't resist watching the processes and the gold drop.
I have edited my post acordingly.

 

[bswartzwelder]

Palladium, I used 1 liter of water and 200 grams NaOH. Put it on the heater at 1:38 and took it off at 3:18. Perhaps the extra 20 minuts might have made a difference. It was boiling slowly the whole time with a lot of stirring.

Edit:
Perhaps this batch had some different type of glue.