Harvesting Help

[seanengman]

So I decided to tear apart some old junk I had laying around to see what this was all about. I also thought it to be a good idea to search around where I work to see what kind of waste I could acquire and I found one thing that suited my needs... but it wasn't the funnest thing to open up. Think of a titanium tin can built to last for 15 years.

This is where the outer wires connect to go inside the machine. I will do better not butcher the next one I tear apart.

This is the circuit board inside of the titanium can. See all of the gold footing and the gold board?
Now, how do I clean up that board and seperate all of the components to get it ready for processing?
I have almost an unlimited supply of these at a rate of about 1 per day... plus or minus.

This is the front part of the car cd player I tore into. How do I harvest all of the little white button things with the gold in them?

Thanks

Sean

 

[Geo]

first thing to do is download a copy of Hokes book and read it to understand the basics of the processes it takes to refine the metals. that being said, are all the traces gold plated or just the areas that are exposed? if they are you will need to remove the solder mask (the green film covering the traces). visit www.goldrecovery.us which is lazersteves website. he has some free videos which you will find interesting. one shows how to remove the solder mask. another shows you how to remove the gold foil from the board (its the same as fingers). of coarse you will need to remove all the components first. soaking the boards in hydrochloric acid (muriatic acid) will remove the solder and release the components. never bring acids indoors, all fumes are dangerous. wear PPE's and work outside or a well ventilated area. remember to read Hokes and continue to read the forum. ask questions when you need to but try to find the answers for your self. everything you need to do has been posted on the forum many times already, use the search feature.

 

[kuma]

Hello , how are tricks ?
Heres a link to a GRF page concerning depopulating boards ; http://www.goldrefiningforum.com/phpBB3/viewtopic.php?f=39&t=831 , it has some ideas for different methods of removing the components.
The square chip with the white sticker in the centre of the board (in your third picture down) is an ICB , these usualy (in my limited experience!) contain gold wires , although you will need a microscope to propperly see them!
Scratch a small area of the green solder mask to see if the the whole board is gold plated or copper.
Most of the time the on boards that I come across , only the small exposed copper parts are plated for protection with gold.
As mentioned , scratch a small area , not too hard though as you only want to go deep enough through the solder mask to expose the top of the metal surface underneath , and look at the colour.
The difference in colour between copper and gold will be obvious! :mrgreen:
If it turns out that the whole board is gold plated , then I think the plan is to go ahead and depopulate the whole board then process.
I really don't know enough to tell you wether or not it would be worth the time depopulating the whole boards just for the small round specks , if it did turn out that they were not gold plated.
I hope that any of that can be of use to you!
All the best with it and kind regards ,
Chris

 

[seanengman]

I found these in a rechargeable battery pack.

Geo-
I downloaded Hoke's book last night and read for a while. Not a bad read. Yes, all of the traces are gold. So, if I understand you correctly, I save up a bunch of boards and dump them all into some muriatic and that cures the component disease? I will try to watch the videos again, but the last time I tried they didn't run. It would be nice if those videos were on youtube.

Chris- Thanks for the advice and link.

Cheers

Sean

 

[Geo]

yes. lead was banned in solder in the late 70s or early 80s depending on where you lived. today solder on common electronics is mostly tin and muriatic acid will dissolve the tin in the solder. use a glass container made to be able to be heated such as Pyrex and heat the solution below a boil will speed things up. without heat it will take a couple of hours, with heat maybe 30 minutes. don't be surprised by the appearance of the board as it comes out,the gold will look black. since you cant see the videos you can remove the green solder mask with sodium hydroxide Na-HO (lye in water solution) this is caustic soda so wear gloves, if you have an exhaust fan over your stove you can do this in the kitchen. use a crock pot or glass pot large enough to fit the board inside. add 1/4 cup lye to 1 quart of tap water, 1/2 cup to 2 quarts of water and bring to a simmer *do not spill or allow any solution to touch aluminum pots or utensils or trim* lower heat to keep solution hot. soak each board for up to 5 minutes ( usually less ) do not over heat as this will cause the solder mask to adhere even more tightly. after soaking use a plate to transfer to the sink and rinse with cold water. the solder mask should be melted and will rinse right off. rub or use a stiff brush for the tougher spots. after all the boards have been soaked and rinsed discard used solution down the drain with cold water running. do not discard down drains with aluminum parts.

 

[seanengman]

Thanks, you guys are great.

 

[eeTHr]

When working with lye, I recommend a full face shield, as is worn when grinding metals, and a baseball hat turned backwards. Also rubber gloves, and a long sleeved shirt buttoned to the top.

Lye can do more damage to you than acids. Even a little splatter.

Never, never, ever get lye in your eye.

No matter how careful you are, there will always be some splatter with liquids, sometimes so small you can't see it, but look at your gloves after working with acids after a week or so! There are always some spots on them.

And obviously, don't breath any fumes!