Refining gold from connector pins

Hi folks.

I am a dude from Norway, wanting to refine gold from the vast seas of e-waste, computers and such.

I can tell you that I have, or can gain access to a lot of computer boards and mobiles and so on, and I also have fixed a supply of chemicals.
I can aquire Nitric acid, HCl, sulfuric acid, Hydrogen peroxide, SMB, tin-powder and others when they are required.

Then, my question is about the connector pins that are gold plated, that are attached to motherboards and other circuit boards inside PCI-slots, RAM-slots and so on.
Refining of gold from the fingers that connects such boards to the connector pins, are very well explained in lasersteve's videos, and I will use the AP method for those.
That goes for the pins attached to processor-chips also, where I will use HCl, and then aqua regia as explained here:
http://www.goldnscrap.com/index.php...fiber-cpu&catid=36:scrap-cpu-a-chips&Itemid=2

But I can not find a good tutorial on getting the gold off the pins that it clearly is lots of on this boards, I throw in some pictures just to clarify 100% what I mean
1:

2:

3:

4:


As I have found, taking a lot of boards apart already, there is a lot of metal that is gold plated all over a computer.
I have gathered just over 300g of this pins by hand in 2 days of work, me and a buddy is doing this as a hobby, and we are determined to learn and succeed.

So what I want to have here, is a tutorial or walkthrough of how to remove the solder without much pain, and to separate the gold from the pins in a effective way (Is HCl the best way to go here? Or does stannous chloride break down gold and making it hard to get?). After what I can understand, the pins are composed of many different metals, and the aim I have is to be able to process all pins in the same go (600-1000g maybe at the time?), without to much leftover waste. Then, the process from there will be the Aqua Regia process described here:
http://www.goldnscrap.com/index.php...-refining-and-melting&catid=25:gold&Itemid=20

Thank you guys in advance And I will post pictures

the best tutorial is at the same place you found the AP videos. lazersteve has some videos of the sulfuric stripping cell, this is the recommended process for removing gold plate from base metal. use steves search engine from his website and search for -gold cell-stripping cell-gold stripping cell, separately of coarse. you will need to remove the gold plated metal from all plastic and other non-metal material.

Dude4ever

Welcome aboard.
As you said so yourself, different pins are composed of different metals or alloys where the only structural commonality is the fact that they are gold plated.
There are several acceptable approaches to dealing with plated base metals:
- A selective lixiviant that will attack only (or mostly) the gold (such as cyanide or Thiosulfate/thiourea)
- Solution of all bese metals beside gold (HCl leach, dilute sulfuric leach, AP, dilute nitric)
- Reverse-electroplating (strong sulfuric, either stationary or tumbled)
- Smelting and electrowinning

To Determine what's best route for you, there are several points you need to consider beforehand, i list them in descending order of importance (the way i see it):
- What are the base metals?
In electronics, base metals are (for the most part) either ferrous based such as Kovar or SS or Copper based such as beryllium copper, brass, bronze and more.
- What are your intentions?
is it for fun and hobby or shear profit?
- Accessibility to chemicals , their costs and your labor costs.
some times, the same type of feed stock could be handled by different procedures, some procedures will require your full attention (Reverse-electroplating for example), others will allow you to leave it alone and free you up to do other thing, the AP methode for example does not need your attention but it comes with the cost of large amounts of waste solution. Get the picture?
- Immediate Environmental impact and waste treatment.
What setup is required for the different procedures so you will not hurt yourself and others, what are the costs?
How are you going to dispose waste metals solution, how much will that cost you?


All in all, THE BEST methode is in the eyes of the beholder.
You have got much learning and reading to do, use the search feature and enter terms written here above and those Geo suggested to you. Everything you need to know had probably been written here before.
When you start experimenting, do so first with very small batches to get the feel and understand the dynamics, It is also important for your own safety if you are not accustomed with chemical reactions and resulting effervescence.

Stay safe and good luck.

Thank you Sam and Geo for replies, I have a good feeling about this.

I first wanted to see if there was a way to get rid of the base metals, and process the gold at the end, but as you pointed out, one method is:
Solution of all base metals beside gold (HCl leach, dilute sulfuric leach, AP, dilute nitric), but this seems to use a lot of chemicals and producing a good amount of waste. And my concerns about the solder and HCl mixed together is somewhat unanswered at this point.
Cyanide is out of the question because of it's toxicity, I haven't asked at the pharmacy, but I doubt that they want to sell that chemical.

The most fitting method just have to be the sulfuric cell for these pins, although it requires full attention, this add up with my free time,
and I can use lesser amounts of chemicals, even reuse the sulfuric, and then refine the gold from there. Plus the different base metals are not something of great concern that way.

I do this because it is fun and I wanted to have chemistry as an hobby, gold refining is a great way, but the focus of it all is profit.
I get the scrap I recover the gold from almost for free, 30$ for throwing the scrapmetal away, and 0$ for taking new(old) unprocessed scrap with me at the same place. I think it is the same price or less for disposal of chemical waste.
So I do not have much expenses with this, just the chemicals, and a one-time investment for glassware and personal safety gear.

Chemicals here is kind of cheap except from the SMB and the nitric acid, but I have only been able to get 65% nitric, from the pharmacy of course (175$), I hope this is enough concentration (destillation??). My glassware were ordered brand new today, and my setup is now almost complete. just have to clear out the garage that also is very well ventilated.

Yes I will start with small batches, but enough to get some gold to play with. For my first run I will run CPU-chips in HCl and gold foils in AR, as that process seems very straight forward, and I do not get to lose sight of the gold. When my drain cleaner arrives (cheap) 96% sulfuric acid, I will start to get familiar with the stripping cell.

I will post everything I find and learn here in this very post, so that the technique and how it works out, is all at the same place.
Thank you again

dont do any process that contains nitrates inside without a fume hood, even a well ventilated inside space. remember that NO respirator will filter nitrogen dioxide fumes. keep in mind as well that AP solution used inside a shed or garage will do terrible things to any metal within the enclosed space. if you dont have a fume hood, its advisable to do these processes outside.

i have COPD and am on every medicine made for the ailment and have never smoked a cigarette in my life. the one factor that i can think of that could have been the cause is, many years ago i made nitric acid for my dad and some friends that were prospectors on a daily basis for months at a time.i had no idea that i was killing myself and that the effects would cause the suffering i go through now just trying to breath.all the days of coughing up blood and feeling sick all the time, i had no idea it was because of what i was doing. this is why i push safety like i do.im not trying to frighten anyone but trying to inform them that this stuff can be done safely.just dont take it for granted that this stuff is not as harmful as people let on.

Okey, thank you, I will proceed with my original plan and place the setup outside, got a nice place for it.
Really good you are here, and are here still, Geo. I am very concerned about safety as well, so I will use any advice you guys give me about it, and everything else as well.

Sounds to me like we might have another valuable member in the making, like his approach and he seems to be willing to read, study and listen to those who have been there before..excellent!

If you process copper items with your AP it is forever reuseable. Iron and other base metals tend to eventually foul the solution over time.

Your solution volume will grow as it absorbs more copper. The excess portion is poured off and treated with more copper until saturated to be sure no values are dissolved in it. Next add scrap iron to the excess solution and recover the copper as a spongy moss. Finally neutralize with sodium hydroxide and properly dispose of the filtered solids. The clear colorless liquid is salt water.

There is a way to electrolytically extract the copper from the AP solution as it is absorbed but this requires a lot of specialized equipment.

Steve

lazersteve said:

If you process copper items with your AP it is forever reuseable. Iron and other base metals tend to eventually foul the solution over time.

Your solution volume will grow as it absorbs more copper. The excess portion is poured off and treated with more copper until saturated to be sure no values are dissolved in it. Next add scrap iron to the excess solution and recover the copper as a spongy moss. Finally neutralize with sodium hydroxide and properly dispose of the filtered solids. The clear colorless liquid is salt water.

There is a way to electrolytically extract the copper from the AP solution as it is absorbed but this requires a lot of specialized equipment.

Steve

Click to expand...

I remember from your video that you have a large plate of metal in your large bucket, so I assume that is what you mean by adding scrap iron to the excess solution?
Does the copper precipitate on the metal plate? I'm going to use your AP method in the videos for processing fingers, and I got some old mobile phones that I already have
stripped for solder mask using hot NaOH - super effective, and it appears to be gold on several connector-spots over copper on this cards, may AP work on those, too?

The iron is only added to excess solution that is not going to be reused.

Steve

I recieved and picked up my nitric acid 65% today. Things are getting into place. I want to do this as much by the book as possible, so that I can not screw up my first batches. I have read through the procedures several times, and watched many videos several times.
I just like to have all of the equipment before I try to do my batches.

Glassware is checked, gold items check, acids check, bases check, H2O2 3% check, hotplate check, glass rod, funnel, filter paper, 2x safety gear check, torch(butane) check, glass stripping cell waiting, ceramic stripping cell obtained and tested w/H2SO4(cold) exposed for 3h - check, cathode/anode/melting dish waiting, battery charger 12v (220V inlet) check, tin powder waiting, sodium hypochlorite checked, sodium bicarbonate checked, sodium metabisulfite-SMB waiting (5days), coal not found - yet, combustion vessles - easily obtained, waste containers and disposal - check, outdoor setup w/table and carboard tomorrow, time check.

If anything essential that has been left out here, that I did miss to write down comes to mind, please let me know will ya?
Some of the items was ordered from lazersteve, very convinient as I was about to buy a lot of lead to make cathode, and tin powder is also relatively expensive here, so thank you Steve, last update for package: ""Customs clearance processing complete April 20, 2012, 7:47 pm, location NORWAY"". Very nice

Regards, Erik

And by the way.

I did a test with a ceramic vessel as a stripping cell. Downside is you can not see through it, but I got one that is white.
I poured some cold 96-98% sulfuric acid (1000ml = 1850g in the flask), into the vessel, and let it stand outside for 3 hours - I saw no difference in texture or colour. just to mention that it could be possible to use this. Note that it was cold and that I did not heat the acid prior to, or after the addition. So anyone else that may have knowledge about this, speak up I will test it myself later on though.

To Steve:
OK I see. I downloaded the PDF on the Acid Cupric Chloride method, and I will use this as my guide to regenerate the AP solution, but because I'm mainly going to use hydrogen peroxide, I'm waiting for your completion of this. In the meantime I will use your video on this, that video is nicely put together, easy to understand, and very informative.
But the choice you and many others make; either dissolving the final gold foils in HCl-Cl, or dissolving it in AR. You choose to use sodium hypochlorite bleach, is this mainly because of either, 1: the quantity of the foils, 2: the thickness of foils 3: the rate of dissolution, 4: cost of AR process, 5: a mix, or 6: something else/more?

Cuz, how pure gold can you get from the HCl-Cl process and using SMB? Equal to AR or not quite that good? And what about Re-refining?
Thanks

Regards, Erik

Erik,

Regardless of the method by which you choose to dissolve the gold foils, your gold purity should be the same if you follow proper cleaning and washing techniques as outline on the forum.

Steve

lazersteve said:

Erik,

Regardless of the method by which you choose to dissolve the gold foils, your gold purity should be the same if you follow proper cleaning and washing techniques as outline on the forum.

Steve

Click to expand...

Hey Steve.
Want discuss a problem that I facing from 4 years of refining.
Pins from mobile boards(battery connected, sim jackets, charging jecks.. )
Whenever I start processing pins it makes a headache.
I saperate pins. Burn plastic. Little crush to break up burnt plastic to free the pins.
Use HCl and a little amount of nitric.
The problem starts from here.
Solution turn black after few hours. Filtering it and no result
As I know gold repercipitate from solution back on metals, it consume too much of HCl. Any other good idea to avoid from it. A lot ways but all are with a new phenomena that required more chamical , not suitable for 4 to 5 kg pins
( I dry the stuff and re use HCl and nitric. . if it go wrong again then one more treatment)