# Science project: Recovering gold from SIM cards



## lesuth (Mar 26, 2015)

Hello guys I need help with the process of recovering gold from SIM cards
I need this for a science project, I've gathered around 100 SIM cards,
The extraction process has to be successful on the first try so I need to get this right please help with the step by step process.
Thanks


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## MrMylar (Mar 26, 2015)

Before you ask for a step by step process, you need to know the basics. If you don't know the basic steps, then you need to keep reading this forum and download Hoke's book.

As far as the 100 sim cards you have, you won't get any noticeable amount of gold out of that. You'll need at least 500 - 1,000 to see any recoverable gold. And even with 1,000 sim cards, you might get maybe 1/10th of a gram. You'll be lucky to get 1g gold with 10,000 sim cards.

I processed them before and you will need lbs of them to make it worth your while.


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## Smack (Mar 26, 2015)

Pick a different project if you want a passing grade this year.


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## MrMylar (Mar 26, 2015)

Smack said:


> Pick a different project if you want a passing grade this year.


 :shock: 

Fingers from R.A.M. or boards would be much easier and faster IF he knows what he's doing. Fingers from 10 lbs of RAM would bring some visible gold.


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## Darkness Falls (Mar 26, 2015)

Is this for a school project? There are some real concerns of how you would go about doing this. If you plan to do this live, do you have the proper fume hood/cabinet setup to handle the toxic fumes? If not, your science fair project could literally kill your entire class.


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## patnor1011 (Mar 26, 2015)

100 new unused sim cards will yield about 1 $ worth of gold, could be less it all depend on type. That is if you are lucky and recover it all, based on that you never did anything like that before as you are asking for step by step process. There are few processes documented on forum, you can find them all but in your case and with 100 Sim cards you are going to spend many times more over what you are going to recover.
http://goldrefiningforum.com/phpBB3/viewtopic.php?f=53&t=19050


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## lesuth (Mar 27, 2015)

It's a project in a university, I am a chemistry major I will be taking all precautions, don't worry I've worked with chemicals before obviously. I was just interested in the best process so I can get a higher grade.
I don't care about the amount of gold recovered, as long I recover something it will mean my experiment is successful. I'll probably turn the recovered gold in some form of a compound after i extract the gold, but the first part where I recover the gold will be more difficult that's why I asked for your help
I'll download the Hoke's book, thanks for the advice


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## Darkness Falls (Mar 27, 2015)

lesuth said:


> It's a project in a university, I am a chemistry major I will be taking all precautions, don't worry I've worked with chemicals before obviously. I was just interested in the best process so I can get a higher grade.
> I don't care about the amount of gold recovered, as long I recover something it will mean my experiment is successful. I'll probably turn the recovered gold in some form of a compound after i extract the gold, but the first part where I recover the gold will be more difficult that's why I asked for your help
> I'll download the Hoke's book, thanks for the advice



It's awesome to here that you have those facilities available to you! Hoke's book is a great resource. If this is strictly for a grade, it may suit your interest to buy some more material to scrap and refine. It would be nice to get a few grams of gold out of this endeavor. Good luck with your studies!


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## lanfear (Mar 27, 2015)

Hi

While you read hoke, you can also look at this process as a potential recovery method. http://goldrecovery.us/goldrecovery/documents/CuCl.pdf
Then you will need to pick a refining method. Good luck


Edit: typo


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## Harold_V (Mar 28, 2015)

lesuth said:


> I'll probably turn the recovered gold in some form of a compound after i extract the gold,


Hmmm. 
Before doing so, check the Merck Index in regards to compounds of gold. They can be interesting. 

And lethal. 

Harold


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## solar_plasma (Mar 28, 2015)

Though it will be next to nothing, if you reduce and melt it, it will be visible as yellow coloured solution, if you first leached and washed well all base metals from the material. It doesn't need much gold to get a slightly yellow solution and even less to get a purple reaction with SnCl2. Then you will have something to show in a computer aided spectrophotometer before and after reduction and precipitation. Use SnCl2 to confirm before and after. Be aware of any excess SO2 would give a false positive with SnCl2. Use standard gold solutions to check your SnCl2 and to compare gold concentrations with spectrophotometer.

Be aware of there isn't only plated gold, but also bondings and gold solder in the chip. With pliers and a sharp knive you can split the chip from the plastic card. The back is mostly transparant and you can see the gold bonding with a magnifier. The chip needs to be incinerated completely to white ash with absolutely no carbon left (it would adsorb some of the gold).

Success on the first run will be an almost impossible task, so use 12 good ram sticks (~0,1g-0,2g Au) first to get familar with the processes. Always leach base metals first. Read about Harold's washes, use only as much nitric as you need, read about the gold button method or sulfamic to expel any excess nitric.

How much time do you have to finish your science project?

Don't experiment, but tell us, what you are going to do, before you do it.


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## lesuth (Mar 28, 2015)

What I found out so far:
1.treat with hot NaOH to deal with the plastic etc..
2.Dissolve the basic metals with nitric acid
3.Dissolve the remainings in Aqua Regia
4.Precipitate the gold
then i guess decant and a filtration.

This is what I found out.

Btw I have until 15th of April to write the complete process of how I am going to do it.

EDIT: Thanks guys for all the help so far.


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## Barren Realms 007 (Mar 28, 2015)

You would really be better off buying some pin's off of ebay to do this project.


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## solar_plasma (Mar 28, 2015)

lesuth said:


> What I found out so far:
> 1.treat with hot NaOH to deal with the plastic etc..
> 2.Dissolve the basic metals with nitric acid
> 3.Dissolve the remainings in Aqua Regia
> ...



1. You can drop 1., if you split the chips from the cards mechanically. I guess this will take 1-2 hours for 100 pieces and can be done while watching tv.
2. Then you dissolve the copper and the thin nickel layer beneath the gold foils. It's ok, but you can also use CuCl2 leach, which has a very interesting chemistry, when you first have understood it. You will be left with solid gold foils, dissolved copper and nickel and the dies with gold bondings covered in plastic. You need to incinnerate the plastic to white ash (no carbon!).
3. Yes. Be sure to understand the usage of AR! We do not use 3:1 for this purpous!! Use nitric dropwise, only as much as absolutely needed. Read what I told you to read in my answer above!
4. Yes. But read Harold's posts about this! 

Following your description to the point you can make a mess or you can achieve the result you hope, - depending on if you are listening or not! I have given you all keywords you will need for your search. Ask, if there are topics you can't find.

2 weeks is not much time! You were better off using RAM for your project.

edit: Yes, or pins. I still advise fingers.

I am not sure, if you will succeed in that short time. But as long as I see that you listen I will try to help you to find what you need.


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## Smack (Mar 29, 2015)

lesuth said:


> What I found out so far:
> 1.treat with hot NaOH to deal with the plastic etc..
> 2.Dissolve the basic metals with nitric acid
> 3.Dissolve the remainings in Aqua Regia
> ...



Select good materials so you can skip step one dealing with the solder mask. Get good non-magnetic pins or better yet close cut fingers and go straight to Nitric Acid then A/R and so on.


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## lesuth (Mar 29, 2015)

solar_plasma said:


> 1. You can drop 1., if you split the chips from the cards mechanically. I guess this will take 1-2 hours for 100 pieces and can be done while watching tv.
> 2. Then you dissolve the copper and the thin nickel layer beneath the gold foils. It's ok, but you can also use CuCl2 leach, which has a very interesting chemistry, when you first have understood it. You will be left with solid gold foils, dissolved copper and nickel and the dies with gold bondings covered in plastic. You need to incinnerate the plastic to white ash (no carbon!).
> 3. Yes. Be sure to understand the usage of AR! We do not use 3:1 for this purpous!! Use nitric dropwise, only as much as absolutely needed. Read what I told you to read in my answer above!
> 4. Yes. But read Harold's posts about this!
> ...


Thanks for the help,
I can't seem to find Harold's post about the 4th step


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## solar_plasma (Mar 29, 2015)

Getting pure gold (shining)

About proper washing.

Filtering and Adhesion

How to prevent gold stucks to beaker, prevent cross contamination.

dropping out gold

Harold's one-beaker-style.

light green ar wont drop gold

Testing - the eyes of the refiner.

Only four examples. Equal posts are spread all over the whole forum, but all of them are worth to read. Sometimes, there are more ways to do things - the discussions between the seniors are PRECIOUS! -, but if you want perfect results in short time without confusion - read, learn, live Harold's style! Don't ask, if you can do it another way (NO! in some month or years maybe you will assimilate some details from the other seniors, that would confuse you right now), but ask if something isn't clear.

And don't use urea, but use just as much nitric as needed and use the gold button method or sulfamic acid to expel excess nitric. Try a search on this topic.

Two other links, that might be of interest (chemical equations):

What drives the dissolution of metals

What is exactly chemical process and why gold drops?

How much nitric:
How much nitric...

How much SMB:
How does SMB work?

By the way, do you have to show the whole experiment live? If so, you either have to prepare all the main steps like in a cooking show, otherwise it would take days. Or you might want to ask the chemists of the forum on how this is done faster with the proper hardware in a analytical laboratory. I have no clue about, how they are working there, if they use centrifuges, expensive analytical glass filters etc.


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## lesuth (Mar 29, 2015)

solar_plasma said:


> http://goldrefiningforum.com/~goldr...as+everything+to+do+with+how+you’re+refining.
> 
> About proper washing.
> 
> ...


Thanks a lot man, you've been VERY helpful and that's an understatement 

Yes, the professor and the assistant will be overseeing the whole process and will be asking questions about each step and monitoring my work ( Do I handle all the equipment correctly, how do I handle the waste and so on... , obviously if the experiment is more complex you can make more mistakes ),and no the experiment is not limited to a short amount of time it can take up 3-4 weeks if necessary


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## solar_plasma (Mar 29, 2015)

> and no the experiment is not limited to a short amount of time it can take up 3-4 weeks if necessary



Perfect. If it were me I think I would spread the process to three days. But as Smack and BarrenRealms already said, you are better off using a better yielding and easier processed material like close cut fingers from PCI cards and RAMS.



> Thanks a lot man, you've been VERY helpful and that's an understatement



It's a pleasure to me. I would love to be a student again and choose refining as the examination project in chemistry subject didactic instead of....*thinking back*.... food chemistry if I remember correctly ...or has it been soap and surfactants ...:lol: and getting an A instead of B or C....long ago. :mrgreen:


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## lesuth (Mar 30, 2015)

I might do it with RAMS if I find some on time.
But it's a bit different method with computer RAMS isn't it?
I saw one video on youtube doesn't look hard at all with RAMS 
https://www.youtube.com/watch?v=rM87TEZXCfg Check it out and I would like to hear your thoughts on this.


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## solar_plasma (Mar 30, 2015)

No, he has no clue about the "magic" of CuCl2-"kungfu", when he uses that much H2O2, he might even dissolve some gold and dispose it. This is like using a laser scalpel as a hammer.

AP=CuCl/CuCl2/HCl+O2-system is really interesting and can be used, but there is a little more to learn about it, than just using nitric instead. So, you're fine with nitric for this project.

So the process for the foils is the same. If you also want to incinerate the chips, you will need nitric for leaching basemetals and AR for the gold bondwires on them to work through the fine white ashes, which also can be gravity separated before leaching. But this is another story and link. Better have the focus on the easiest stuff now: plated fingers and traces.


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## solar_plasma (Mar 30, 2015)

If you also want to process the chips, soak up this thread: http://goldrefiningforum.com/~goldrefi/phpBB3/viewtopic.php?f=52&t=11827
But only if you have the time after all the other reading stuff, which I do not expect you will have. This and the CuCl2 philosophy would triple the time needed.

With the limited time you need to focus and limit the number of processes needed - be effective. We will not make you become a refiner in this short time, but we can help you finishing a good solid project. And that is only possible because you have a good chemical background and *because you obviously are listening and learn by yourself*. Well done so far.


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## g_axelsson (Mar 30, 2015)

That was way too much nitric in that movie also, mixing AR with a ratio of 1:1. I think he has learned all he know on youtube.
Way too many errors in that video to list them all.

Göran


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## solar_plasma (Mar 30, 2015)

:shock: I didn't have the self-discipline to watch it to the end! His HCl/H2O2 has already been too much for my nerves.


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## pattt (Mar 30, 2015)

Hi all,

Lesuth, that youtube video is so wrong, 

I would use the hcl/peroxide way (but the way it should be done) and then I would go for the "hcl and sodium hypochlorite" way,
for foils thats strong enough and you don't need to evaporate the AR or worse use Urea yo get any excess Nitric acid out.
And finnish with Harold's washing method :!: 

I don't like to refer to my own post,(I am just a beginner) but I think the picture in it shows that you can do a better and safer refining project by reading this forum and Hoke's book then following the wrong youtube videos

http://goldrefiningforum.com/phpBB3/viewtopic.php?f=60&t=18683&p=188464#p188464

I hope you're project will be a success

Pattt


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## lesuth (Mar 30, 2015)

AP seems interesting, too bad i have exams for physical and analytical chemistry as well which limits my time for research I guess I'll stick with nitric.
Though all videos on youtube are with the AP method. By the way I probably will not incinerate the chips and the ram cuts because that would require to move to a different laboratory, would that be a problem if I don't do any preliminary treatments?( talking about the chip and ram fingers)


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## solar_plasma (Mar 30, 2015)

Right so, don't let you confuse by the many ways it could be done. If there is time in the end, you can easiliy implement more.

The RAM do not need to be cut, you can also break off the gold fingers with pliers. A clean cut is to prefere ofcourse.

@all
*folks, this man has only 2 weeks to finish the abstract, so don't confuse him, think twice, what advice you give! It is no hobby to him, but he will get examined on this.* If he has tme left in the end, we still can help him learn the AP(CuCl2), which easily can be implemented. Dill. nitric is faster, simpler and for an experienced laborant not more dangerous, it is just a little more expensive and harder to obtain to many, but this is no criteria in an university lab.


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## pattt (Mar 31, 2015)

Solar , Maybe you should read his post better ,

He said :



> By the way I probably will not incinerate the chips and the ram cuts because that would require to move to a different laboratory



So He is talking about not incinerating the ram chips or cuts, (clean cut fingers)
and asks if the 'not incinerating' would be a problem.



> this man has only 2 weeks to finish the abstract, so don't confuse him, think twice, what advice you give!




Greetings
Pattt


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## g_axelsson (Mar 31, 2015)

Cut fingers from ram does *NOT* need to be incinerated.
Plastic IC:s *MUST* be incinerated to liberate the bond wires.

Do not mix up different processes, or you are sure to make a mess.

Göran


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## solar_plasma (Mar 31, 2015)

Thank you Pattt and Göran, I had missunderstood him on that. Offcourse Göran ist right!

Still let us stay close to what he originally wanted and not offer him to many methods to choose from. He has not the time to make his own choice AP or nitric and AR or HCl/Cl. Most will use AP and the HCl/Cl, but this is not, because it is better in all cases. It's just the best choice in most individual cases.


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## FrugalRefiner (Mar 31, 2015)

I'm going to agree with Björn on this. Lesuth is a student. Björn is a teacher. Let the man teach. If you see an error in what is said, as Pat and Göran did, feel free to point it out, but don't confuse our new member with talk of other methods.

This thread is also a perfect example of why members are so resistant to give quick answers to quick questions. What we do is complex. In just a single thread, we've managed to confuse a new member on which material to pursue, and the preferred methods to process it. What we do and how we do it depends on our own particular circumstances.

This situation was special. Lesuth didn't come here with a case of gold fever, proposing to dump his toxic waste down the drain. I commend every one who has tried to help. Every situation is different. He has limited time, but access to nitric and hydrochloric acid, a proper facility in which to do his work, and I assume, some degree of supervision in the lab. 

I wish you luck lesuth. 

Dave


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## Asiacdurr (Apr 9, 2015)

I have about 3k of used SIM cards I could give you. Message me.


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## lesuth (Apr 11, 2015)

Hello guys, I got my hands on some chips and ram, I cut the ram fingers like shown on the picture and they are ready to be processed. Wanted to ask you how do I prepare the chips? Do I try to just remove the needles or dump them whole ?(it would waste a lot of nitric acid if I do that tho).What are your thoughts on this?


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## solar_plasma (Apr 11, 2015)

The CPU pins are made of kovar, which is slower to dissolve. Further you have to deal with tin first, it could make a metastannic acid mess with nitric. The problem is, each of them is normally processed in an other way. I would wait if other members will advise, if you should include the CPUs in your experiment at all. 

The ceramics are the smaller problem. The black fiber makes problems since you cannot reach the copper traces in that epoxy, so your gold could cement on them and you will have losses. This one should absolutely not be part of your processes. The green fibers are extrem low grade, 100-200 make one gram gold, but the pins can be removed with heat. If you want to use the ceramics and the pins from green fiber, you need to leach tin first by HCl, then wash and incinnerate well to remove all chlorides(!), finally remove copper with nitric (if there are traces of chloride left, this will dissolve some gold also, which you don't want in this step.

[A possibillity is to go straight nitric, vacuum filter, dissolve metastannic in a strong NaOH soak, wash,filter and go on to AR. - if this is confusing, forget this sentence immediately.]

When only ceramic, silicium dies (which have to be fallen off the ceramic(!)) and gold is left, then you dissolve the gold. If you want, together with the foils from the PCI cards amd RAM fingers.

Sometimes some of us process different materials in some steps together, but then we know what we are doing and know how to deal with the disadvantages.

Anybody who chimes in, should have read the whole thread. This is not the usual youtube wannabe backyard refiner and this experiment is not done for any profit other than he has to get his examen. Think well, not to confuse him with to many processes.

Hope this helps!


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## lanfear (Apr 11, 2015)

Just a small input. There is actually no need to treat the ceramics in nitric first. They can go straight to AR. Only the gold plated lids need to be removed and can be treated with nitric to get the gold of. And then dump the gold from the lids and the fingers in the AR with the ceramics.

Jon

Edit: gramar


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## solar_plasma (Apr 11, 2015)

If you can avoid it, you don't want to dissolve gold along with basemetals.

And forget all about your last post, this is making a bad stock pot. Nothing is won. You skip one step and you add...I can't even count how many steps...5 at least. And you will have losses and other problems.


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## solar_plasma (Apr 11, 2015)

Remember, we talk about some 0,1g of gold, not of kg. You have to work accurately or you will not get any gold, you will not even know, where it is gone. And if you recover half of it, you can't melt it, because half of it is copper and other garbage.

Many of us have started with those mistakes, but we had time to get back and read again. You don't have any time for playing. Doing it the most proper way, you can see your gold all the time, until nothig but gold and insoluble solids are left. Then, after dissolving, dillution, dropping lead and silver, settling and decanting you have a beautiful crystal clear yellow solution that is easy to test and fast to precipitate.

This precipitate will have a good quality after the washing and if everything has been done properly, you can melt it or redissolve it and drop by another precipitant or the same and wash again to get higher purity.


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## lesuth (Apr 11, 2015)

So it will be a lot easier if i just removed the gold plated needles and dump them together with the RAM cuts in nitric acid , then go to AR and so on...


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## solar_plasma (Apr 11, 2015)

Remove tin first, if you don't want to deal with metastannic sludge (see above).

The pins from the ceramics can not be removed by heat, as far as I know.


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## Anonymous (Apr 11, 2015)

Bjorn if I may?

Part of the confusion that may arise from the advice being given with regards to the processors is that there are three distinct types of processor on that picture- each with a distinctly different process required to obtain the gold.

As has been suggested before I would agree with the advice to stick with the fingers and leave the processors out of it for the purposes of this report.

Unless of course you want to advise on the complete range of processes?

Jon


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## solar_plasma (Apr 11, 2015)

Jon is right. Each additional process adds the risk that a detail does not work like you expected, that you do a mistake, that your professors ask something you have no answer to. It would be something else, if you had enough scrap and time to become familar with the processes from morning till evening. If you can, try to get 200g of clean cut fingers. This will yield +/- 1g gold. 

Better be a little expert in one process, than a dabbler in many.


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## heliman4141 (Apr 11, 2015)

solar_plasma said:


> Jon is right. Each additional process adds the risk that a detail does not work like you expected, that you do a mistake, that your professors ask something you have no answer to. It would be something else, if you had enough scrap and time to become familar with the processes from morning till evening. If you can, try to get 200g of clean cut fingers. This will yield +/- 1g gold.
> 
> Better be a little expert in one process, than a dabbler in many.




That is a VERY good quote on this forum with limited time. 8) 

I agree 100%

Dave


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## solar_plasma (Apr 12, 2015)

Frugalrefiner pm'ed me to tell you more about using SnCl2-test. I hope he will chime in and do it himself with his own words.

Just for the completeness I try to underline some points you have to understand:

the stannous test is your eyes and ears!
test your test with standard gold solution first! 
In a clean, oxidizer-free gold solution you can even get a feeling of the concentration of gold, if you have several different gold standard solutions to compare
use it before and after leachings and precipitations
use it to be sure, no gold has been leached together with the base metal leach
use it to know, where your gold is
after precipitation you use it to know that all gold has dropped out

it will not only show gold (purple or black), but also Pd (green/brown) and Pt/Rh (orange)
it is very, very sensitive
testing coloured solutions you will need to use the spotplate method and look for purple stain
if you overdo SMB, the test will show false positive (maybe because SnCl2 reduces even SO2 to H2S (Wiberg, Inorganic Chemistry), which again will precipitate almost everything as sulfides)

with excess oxidizer the purple reaction disappears again
large excess of oxidizer might prevent the purple reaction (I am not sure about this)

Ag+ will (of course) give white AgCl precipitate with SnCl2
Though in high acidic high chloride matrix AgCl is soluble as complexes (that's why we dilute, settle and decant/syphon/filter before precipitating gold - syphoning or decanting after a day is the high art but takes its time, whereas filtering works as well, if you choose an adequate fine filter material)
before this, we have added a little SO4-- and cooled to drop lead

avoid to let dust fall into your gold solution while settling
Under the second refining:
use only beakers that haven't been used for anything else
they have to be extremely clean, don't touch the inside - dried gold would cling to the walls of the beaker if there are scratches or if you had touched its inside
the whole second refing can be done in that only beaker: precipitating, washing, drying

never "boil" solutions with dissolved values (and if you have to, then reflux in some way)

Ofcourse can I make mistakes, forget details, think/remember wrongly or mistype, - so everyone feel free to comment


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## solar_plasma (Apr 12, 2015)

Since you are starting with dissolving copper (and a thin layer of nickel) with HNO3, I have found a good link for you about the chemistry:

Dissolving copper in nitric (orig.:"Pins in Nitric Acid")

and

How much nitric acid to dissolve 1 pound of Copper?

As you see, there are several possible processes depending on concentration. Further you see, that using dilluted HNO3, preventing too much off-gassing, oxidzing NO and redisolving NO2, will be most cost-effective.


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## solar_plasma (Apr 12, 2015)

Maybe you want to be able to tell your professors, why you have chosen one and not the other method. So, I will try shortly to mention some points about that. In fact you could write a book only about that issue:

*Dissolving base metals (Cu, Ni):*
your choice: nitric acid
advantage: availability, fast, simple chemistry
other options and no-options: 
CuCl2/HCl system - cost effective, slow, advanced chemistry
FeCl3 - same, a little faster, lots of brown stains
persulfates - slow, more expensive, ammonium persulfate would add ammonium to the process and makes it necessary to treat the waste separated
dilluted forms of piranha - too dangerous (process not allowed and not necessary to discuss here), expensive, fast)

*Dissolving gold foils:*
Your probable choice:
Modified AR (=HCl enough to cover the gold and make the solution handy/only as much nitric as needed(see link given)) - fast, but excess nitric must be avoided and/or expelled, sulfamic acid or gold button method - usually AR is only used, if you have to dissolve massive items or leach fine insoluble powders that contain gold, otherwise the other methods are preferred - makes H[AuCl4] or AuCl3 (dilluted solution)
other options:
HCl/NaOCl or HCl/Ca(OCl)2 - strong enough to dissolve foils or powder, excess clorine can easily be expelled by heating, slower, more liquids=more dillute gold solution - makes Na[AuCl4] (could not find the reference)
HCl/H2O2 - works with foils or powders, slowest, no problems with excess oxidizers - probably it makes H[AuCl4]or AuCl3 (dilluted solution)
all other methods make a lot of liquid volume, are hard to control their complicated chemistry or are hard to treat their waste - many of them are applied in leaching ores (leaches)

*Precipitating gold:*
Your probable choice:
SMB and other sodium sulfites - easy handling, must not be overdone (potassium compounds work too, but could form insoluble PGM salts]
SO2 - easy handling, if you have it available
other options and no-options:
FeSO4 - I think it is preferred for dirty solutions, can be used for additional testing
oxalic acid - more complicated to do properly, often preferred for the second refining (I love it]
cementing is no option for the gold refining, only used for recovery from spent or messed up solutions
other options are not readily available, implicate unnecessary dangers and/or are not selective

A little specialty is the appliance of* lquid-liquid extraction solvents*. If you need it, I help finding the links, but I have no clue about it, other than it is a method to get high purity even from impure solutions.

*No option:*
Another specialty in recovery only for the completeness is cyanide leach of plated gold. It is very dangerous (of course), not allowed to discuss here, but in professional/industrial setups often applied due to its cost effectivity and (at least for those who know it to handle really professional) simplicity. - disadvantages: one little mistake=last mistake of your life, waste problematic


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## lesuth (Apr 12, 2015)

Okay thanks for the help. As a matter of fact I do need to write about alternative methods, I did write something about sulfuric acid (compared to dissolving base metals with nitric), and using FeSO4 instead of SMB for precipitation.

I need to know more about the chemistry behind the SnCl2 test, and the CuCl2/HCl seems interesting cause it's cost efficient , but I can't find any reliable literature for these methods.
He will definitely ask me about alternative methods... but I need to know the chemical background otherwise I'll have no answers if he asks in more detail.... like chemical reactions and so on..


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## solar_plasma (Apr 12, 2015)

Chemistry of SnCl2: have a look at Wiberg/Inorganic chemistry, you need to get the book at the library or buy it, there is a description of how and why SnCl2 is a reductant
Sn++ -> Sn++++ + 2e- (+0,154V)

but there are about 2 pages about SnCl2

About CuCl2 lazersteve has written a very nice text: http://goldrecovery.us/\goldrecovery\documents\CuCl.pdf

in fact CuCl2 works like a catalyst, so the reason why this method is cost-effective is, it works with HCl (low g/mol, cheap, would not oxydize Cu without this catalyst) and all HCl uses up effectively. I think saying it is reusable is chemically not correct, you still need to add HCl from time to time. Chemically it is a catalyst and under processing you get more and more of it.

also look at the bottom of his site (documents section): http://goldrecovery.us/site.asp

Search also your university library for extractive - metallurgy - gold - refining, since you need current scientific sources, books that are very (too) expensive to buy.


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## solar_plasma (Apr 12, 2015)

lesuth said:


> I did write something about sulfuric acid (compared to dissolving base metals with nitric)



Sulfuric is slower. If used with strong oxidizers, it is quite dangerous and the exotherm reactions need a consistent controlling. Further the controlling and the oxidizers would make the process more cost intensive. I think it is waste of labour, material and energy compared to the drop-and-forget-methods plus accidents are more probable.

*Since this is not allowed to discuss, I want to underline, that this is only mentioned as a theoretical issue! The reader shouldn't even consider to use this!*


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## solar_plasma (Apr 12, 2015)

I am not sure, but maybe here are some useful diagrams regarding CuCl2:

SKI Rapport 98:19
Pourbaix diagrams for the system
copper-chlorine at 5–100 °C

I am not a chemist, but (correct me if I'm wrong) I think at least it shows why sufficient acid and oxygen is required. Also it shows why and when the solution loses its corrosivity, what species are present under certain conditions and when insoluble compounds precipitate. As a bonus it shows the influence of temperature.


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## FrugalRefiner (Apr 12, 2015)

Lesuth, I sent my suggestion regarding stannous chloride testing to solar_plasma in a PM because I didn't want to be another voice adding to any confusion you might have felt here. Since he has asked that I post here on this thread, I will.

He's already done a good job of describing why we use it, and its importance. Once you dissolve your gold, stannous chloride becomes your eyes. It will tell you which solutions have gold in them and which solutions don't.

I think you can use this testing to great advantage as part of your demonstration. Once you have dissolved your gold and eliminated any excess oxidizer, remove a small sample of the solution. Put one drop in a spotplate well, and another drop in the next well. Add 9 drops of water to the second sample to create a solution with only 10% of the original concentration. Mix, and take one drop and put it in the next well. Add 9 more drops of water to create a 1% solution. Do this several more times creating increasingly more dilute solutions. Then add a drop of stannous to each to demonstrate how sensitive stannous is. 

After you precipitate your gold, you can test the barren solution to demonstrate how complete the precipitation has been. This is the technique we use to determine if we've used enough precipitant. If the solution still tests positive, we know we need more precipitant. If it tests barren, we know we've recovered all the gold that was in solution.

It's a simple demonstration that can be performed in front of your professor.

I hope that helps.

Dave


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## solar_plasma (Apr 12, 2015)

Well said, Dave!

Lesuth, while I drove on the road I got another idea: 

If you want and if you don't get confused, you could process the fingers parallel, each batch with 0,1-0,2g gold (like 12 RAM sticks), one in nitric, one in CuCl2, one in FeCl3 and so on.

When you have harvested the foils, you dissolve them together as one batch. For precipitation you can split it up again, one SMB, one FeSO4 and one oxalic.

It is hard to determine how much we can load onto your shoulders. If you feel safe with the basics of each process, this would make a nice show together with Dave's stannous sugestion. But I think it is necessary to have tried this before the presentation.


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## Barren Realms 007 (Apr 12, 2015)

I think I would stay away from oxalic for now since he is new at this and trying to learn so much. It will be better for him to do one thing and do it good than three things and make a mistake somewhere down the process and damage his grade.


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## solar_plasma (Apr 12, 2015)

I agree.


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## bswartzwelder (Apr 12, 2015)

Some of the processors have aluminum heat sinks attached. This should be removed first either with a screw driver or a sharp knife. Makes no sense adding aluminum to the mix when it can be so easily removed by mechanical means.


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## solar_plasma (Apr 12, 2015)

SnCl2, Holleman and Wiberg, Inorganic Chemistry, the complete page:

http://books.google.de/books?id=Mtt..._ge_summary_r&cad=0#v=onepage&q=sncl2&f=false

(press "page 903"]


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## solar_plasma (Apr 12, 2015)

http://www.www.journalamme.org/papers_amme03/1229.pdf



> and the CuCl2/HCl seems interesting cause it's cost efficient , but I can't find any reliable literature for these methods.



search for combinations of: etch - etchant - etching - copper - chloride - cucl2 - patent - pdf - ph - eh
The web is full of it.


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## lesuth (Apr 13, 2015)

Thanks a lot everyone. I'll finish up writing the... thing (don't know the term in English) today and next week we'll start the experiments. I'll keep you updated and If I have more questions I'll post here.
EDIT: By the way I'll probably stick to processing the rams with one method so I don't mess things up. I just wanted to know more about the theoretical side of the other methods so I can explain more if I'm asked about alternative methods.


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## lesuth (Apr 26, 2015)

Hey guys here is my update.
This week i treated the ram fingers with nitric and dilluted the solution and then filtered it. I put some more nitric to be sure that I got rid of all the base metals. Then I dissolved the gold foils in aqua regia there were some tiny green plastic from the ram fingers in the aqua regia I filtered them from the aqua regia. And the solution was light yellow and very clear. 
I need to synthesize H4AuCl4 ( that needs to be the end product, not gold). So my initial plan was to precipitate the gold out of aqua regia and then redissolve it in aqua regia, then get H4AuCl4 by evaporation process. More specifically I'm gonna make anhydrous H4AuCl4 by using ethanol at the last step of the evaporation process.
So my question is how pure the compound would be if I don't precipitate the gold and go straight to getting H4AuCl4. Because there isn't much gold to precipitate.
EDIT will the precipitation be unsuccessful if there is very little gold in the solution.


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## solar_plasma (Apr 26, 2015)

How many RAM sticks? How much HCl and HNO3?


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## lesuth (Apr 26, 2015)

35grams of RAM sticks
1ml of 15M nitric and 3.5ml 12M HCl, nitric is definately in excess, if I'm precipitating the gold I will probably evaporate it.
Hmm maybe i could neutrilize the excess nitric and calculate how much nitric is actually used to dissolve the gold and from there I could calculate the amount of gold. Well too late for that now.


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## solar_plasma (Apr 26, 2015)

fingers of 1kg RAM sticks (60-70 pieces) yield about 0,5g gold


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## lesuth (Apr 26, 2015)

So, that's about 17.5mg IF I've recovered it all. Guess I'll go skip precipitating the gold.


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## solar_plasma (Apr 27, 2015)

That's why I said, you should try this first and use at least 12 sticks.


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## g_axelsson (Apr 27, 2015)

Another small button, gold from one IC : http://goldrefiningforum.com/phpBB3/viewtopic.php?f=61&t=7056

I advice you to precipitate the gold first, let it settle for a day or two, carefully remove any liquid without disturbing the precipitated gold (test liquid with stannous), then dissolving it again to make more pure gold chloride. If you just dissolve your foils you will have cobalt and probably quite a lot nickel as contaminants.

Göran


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## lesuth (May 14, 2015)

The synthesis was a success guys, thanks all for your help.


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## FrugalRefiner (May 14, 2015)

Congratulations!

Thanks for letting us know.

Dave


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## Barren Realms 007 (May 14, 2015)

lesuth said:


> The synthesis was a success guys, thanks all for your help.



What was your grade the teacher gave you?


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## AquaRegia (Nov 10, 2020)

This may be too late...

I empathize with the student. I too do science projects. I am not trying to make money off of this. Gold is not the only element I process. I experiment with ores of various metals for fun. I would not criticize the young man.

I recently processed some random electronics I was throwing away. Card readers, connectors, etc. it went very very well. No, the gold amount is not huge but that was not my goal. The tenth of a gram or so that I got is real, and proved my process.

So I then bought 100 SIM cards and they all dissolved the metals within an hour or so into my AP solution. No gold foils like from pins and other connectors. Same process. The pads on the outside dissolved in AP very quickly and did not look very “gold” to me. I am following up with the eBay merchant to convince me the gold he claims is there. I am also suspect as the cards appears to have been partially treated in the past. When I agreed to buy “used” SIM cards, I did not take that to mean “used in nitric acid and HCL.” Could the gold have been mostly dissolved to leave mostly copper pads behind and then sold?

Can someone tell me if SIM cards are somehow much harder than pins and gold fingers? Will AP not work for this type of recovery? I read a few threads but there were great differences of opinion and estimations of the amount of gold recovery.

For now I am sticking to pins and ram trimmings and electronics that I recycle myself.


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## Martijn (Nov 10, 2020)

There are several solutions that leach the gold off and leave the copper underneath untouched. 
This sounds like a scam to me. 
He'll never admit that. Good luck getting convinced but i would consider it a loss. 
Sreetips has a good video on it and it shows how much is to be expected.
Almost everything on ebay regarding gold plated and gold 'containing' items is sold for more than the gold value. If any. 
Don't buy scrap unless you know the value and yield and you can see it before you buy. 

Martijn.


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## patnor1011 (Nov 12, 2020)

There is more gold "inside" sim card than on the ouside contact area.
Outside contact area plating may even be worn off due to use mainly on used cards but under pads there are couple gold bonding wires going from pad to a tiny IC in the centre. They are visible on some types of simcards but not on most of them but they are there.
If you want to get all the gold from simcards you need to dissolve or incinerate them whole after you stripped plating from outside.

Read forum - most of your questions were already answered.
Processing smart cards, sim cards


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