Sim Cards

[Palladium]

It could have something to do with the glue type. I've had some stubborn glues before, but the naoh always wins in the end. You might have to try a higher percentage or a longer duration or maybe a combination of both. How old are the chips? Age could play a part. I researched and found somewhere, god if i can remember where, that most modern glues are made from organic sources to comply with the new epa standards about voc's and disposal issues. Naoh breaks down organics well, but not so much for polymer chained adhesives. Glues are generally made from organic or bio-based compounds, while adhesives are chemical-based.

 

[MarcoP]

Sorry to jump in, but where do you find such a big quantity of sim cards.
I've also tested hot 30% NaOH on PCBs for up to twenty minutes, but what made it through was letting it sit, cold, for other twenty-four hours, next time I'll try a longer hot bath and see how it goes.

 

[bswartzwelder]

Tomorrow I will have a little free time and will approach the problem once again. I have already measured out 250 grams of NaOH. Should have enough time in the afternoon to devote a couple of hours to it. I forgot to mention that the time I tried this with the 200 grams NaOH and 1 liter of water left me with a brown ring around the ss pan and some brown residue floating on top of the sim cards. It was all drained/washed off.

Do you think I will need even more NaOH than the 250 grams?

 

[Palladium]

You can try it. Maybe try heating it over a couple of hours and then let it cool over nite and see where your at then. I use to cook some of them for 4-5 hours. Not only would the chip come out of the plastic sim card, but the plastic package the sim was embedded in would wrap and separate also. It made my life easier because if you don't heat the chip long enough the plastic will separate from the sim, but it's kind of stuck in the cavity and the liquid behind the plastic and the chip will create a vacuum effect that makes washing and separating the chip a pain in the butt. Yours may be designed different. Just please watch that hot stuff !!!!

 

[joekbit]

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

Spaceships

I hear you on the recovery from ash. After trying a few things on a very small amount of ash I found HC/CL to be very effective but it will have a bit of contamination. After an initial wash of the ash I dried it and broke it back up to powder. The ash has to be in a thin layer for oxidation. Then I basically turned it to mud with HC and added the CL slowly with a syringe, a dropper would work as well. Just something that will hold the amount of CL you need. So pay attention to how much HC you use to create the HC mud and get 1/3 CL to add to it. It will very quickly dissolve the gold. The reaction is fast but short lived. Its nasty stuff (SAFTEY)

Dilute, after it settles, filter or pour off the fluid to keep and repeat. Pouring it off saves time, and filters. Remember carbon in the ash will absorb some of the CL, trapping it. Not sure what the effects might be, it may lengthen the reaction or it may weaken it requiring a bit more CL. (Still up for debate) lol In short, do it till you get a negative test for gold. I had some burned filter ash in a jar. I now have 4oz of gold solution.

 

[Harold_V]

After trying a few things on a very small amount of ash I found HC/CL to be very effective

I dunno. It may be just me, but it's not clear what you're trying to say here, especially for those who may not use English as a first language.

Would you please clearly identify what you mean by HC, as well as CL?

Harold

 

[kurtak]

Remember carbon in the ash will absorb some of the CL, trapping it. Not sure what the effects might be, it may lengthen the reaction or it may weaken it requiring a bit more CL.

joekbit

First off as Harold pointed out - not sure what you mean by HC/CL &/or HC --- I can only "assume" you mean HCl/Cl &/or HCl

as for the carbon absorbing CL yes that is true enough but that is not the real problem with having carbon in the ash - the real problem is that as gold is dissolved the carbon actually absorbs some of the gold chloride ions as well - in fact carbon can (& is) used to recover gold (& other metals) from "very" dilute solutions - once the carbon is "loaded" with the dissolve metal ions it can then be incinerated to recover the metals

Just as a heads up joekbit - you are new here (only been here a few days) spaceships has been here a couple years so he is way ahead of you on how these things are done - he wasn't looking for advise - he was simply answering my question as to why he does it a bit different then I would (there's more then one why to skin this cat) his answer was fine - I don't like leaching stuff from ash ether - that's why I use a smelting process - not everyone is set up to smelt - which is why spaceships use's another process

My point (& I believe Harold's point) is that you really need to spend some more time reading & doing some research here before you start posting - you may have learned "some" things watching youtube videos & from other places on the net - but I can assure you that you also learned "a lot" bad stuff & down right wrong stuff from those other sources - so you are going to need to get all that BS out of your head

Not trying to be rude &/or insult you - just pointing out that you need to spend more time reading & researching to learn more of the facts about this before you start posting --- as of now what you post clearly shows you still have a lot to learn before you try telling other how to do it

Just trying to get you on the same page as those of us that have been here for awhile & have taken the time to read & research & learn about this - this isn't something you learn in a few days &/or from watching some youtube videos - it takes "research" - & lots of it --- I have been at it for 4 years & am still learning

Kurt

Edit to correct spelling

 

[joekbit]

Kurt

Thanks, I will read and keep my mouth shut.

Joe

 

[patnor1011]

Only about a year ago I posted process along with pictures. It pays to search forum even when you think you read it all. :mrgreen:

:arrow: http://goldrefiningforum.com/phpBB3/viewtopic.php?f=53&t=19050

 

[bswartzwelder]

Patnor, I did read up on SIM cards and saw that thread. Incineration is a problem as I live in a heavily populated development. I have to do most of my work when the neighbors are not at home. I am better now at panning than I was earlier because I bought a Blue Bowl and a Spiral wheel panner.

My chips looked a good bit like the ones in your post. They had never been used and were the chip with the gold plated contacts on them. On the back, the chips were embedded in a clear drop of epoxy (or something like that).

I dislike using NaOH more than words can adequately express. I saw a post by Palladium where he used NaOH to separate the chips from the card and decided to give it a try. I actually tried it twice since the first attempt didn't bring the expected results. The results from the second cook in NaOH were similar to the first. It dissolved the epoxy around the chip and the chip and bonding wires dropped off into my bucket. The glue turned to a rubbery type substance which still adheres to the back of the chip assembly, but it can be rubbed off fairly easily. That's where I am at this point.

I took a dozen chips, six with the glue on them and six without the glue and have them in a 1000 ml beaker with 450 ml AP and an air stone as a test. I don't want to go to AR immediately because of all the surface area of the plastic and the glue could trap some gold.

Thanks for the reply, but I did learn my lesson from not doing so previously. I may end up incinerating what's left of a previous batch, though.