Processing pins from motherboards

[Chris_]

Hi. I was study a forum about processing pm's and when collect an about 470g of mix from isa/pci/hdd and rs232 gold pins (hdd pins and this from cpu socket I scrap and process with plastic) i've got to work. when I started processing I know there will be very little gold at the end but unfortunetly i've got nothing... Below I report steps of process:
- dissolving tin and nickiel in 500 ml HCl about 32%
- filtering pins from solution on vacuum and few times boiling pins in water for get rid of HCl
- next dissolving pins in diluted hot nitric acid. While solution turn to navy blue color I thought there was too much dissolved copper and decided to filtrate it.
- I've got a plastic , filter paper and a dark grey mud and continue dissolving all in fresh nitric acid
- when there was no more brown fumes of NOx, I added little nitric and when no fumes get off, finally added 100ml AR and heating carefoully solution about 30 minutes,
- then I filttate solution on vacuum and evaporating to consistence of syroup, adding conc. HCl and evaporating again.
- next step was dilluting with water and precipitating Au with anhydrous Na2SO3. But solution stay clear and no gold precipitate...
What I do wrong??? Can anyone help me?
Chris

 

[FrugalRefiner]

Chris,

Welcome to the forum. My first thought is that dissolving pins uses a lot of acid to recover a little gold. A sulfuric stripping cell is better suited to processing gold plated items.

Since you chose to dissolve the base metals, my next thought is that you should have incinerated between the HCl leach and the nitric leach. No amount of rinsing will get rid of all the chlorides, so when you added the material to nitric acid you created a small amount of aqua regia which could have dissolved some of your gold. While it should have cemented back out on the remaining base metals, I saw no mention of testing, so you don't know.

That brings me to my third suggestion. Processing without testing with stannous chloride is like trying to drive with a blindfold on. If you dont test, you have no idea when you've put gold into solution. Download C.M. Hoke's Refining Precious Metal Wastes. You'll find links in my signature line. It will teach you how to make and use stannous chloride testing solution, so you'll know when you have gold in your solution.

Dave

 

[Pantherlikher]

Hello and welcome to the forum.

Not to sound or be mean, secretive, or in any way demeaning but...

Your problem arose when you briefly read through the forum and desided you think you know enough to do it.
Based on what you did, you did not learn much more then mixing acids hoping to have an end result.

What about ALL the steps involved in the process you described...
Like using less dangerous methods?
How are you handling the waste liquids you are creating?
How are you testing to find out if you have gold in the first place and where is it? and in what form?

I would venture a guess you used more money in supplies to do this then what the gold you will eventually get is worth.

To answer your delema as best I can...Hmm...
ok.
Safely cover and store everything. Including all liquid and solids you may have.
Next.
Goto waste disposal sections of the forum and learn what to do.
Goto the safety section and learn of the toxic fumes and liquids you created and how to deal with them. Before you hurt yourself or others in your area severly!

After learning about what you have already done unsafely, Learn other methods of "collecting" the gold from pins and other base metals.
Do you know what base metals each of the pins has under the gold plating? You mixed several types of pins so you mixed base metals as well.

Your gold is still there, somewhere. What you tried to do is refine gold before collecting it. You can do this but you will spend more on doing this method several times then the refined gold you will have when done as well as all that hazardous waste you created and now need to deal with.

Does not make any sense or logic in doing it this way.

As you read and learn more, you will come across what is recomended now for you to safely get out of what you have now and you will test for and see your gold, but not in the form you expect.

Please, PLEASE, do read alot more and learn ALL of the steps and processes. You will learn alot and be happy you did.

Good luck and hope to hear your results and someday see a nice gold button.

B.S.