Step by step instructions for AP processing circuit boards

[4metals]

This thread is not for guys who want to chop up the boards and run them on a table or pyrolyze them and smelt them for a copper cell, this is a thread to provide a step by step plan to follow for the hobby refiner or small scale operation that comes across bucket sized lots of circuit boards. This thread is exclusively for using the AP process to release gold foils which can be processed once enough are collected. That will be discussed in another thread so as not to make this thread too confusing.
That said, the starting point is a pile of circuits that have been removed from the computers or phones or whatever and lend themselves to this process.

I guess a listing of what types of material will lend themselves nicely to the AP process will be a good starting point.

One of the problems with reading these things on a forum is we, the moderators, cannot change a position of a post in a thread, at least I don't know how to do it. So a comment made about aqua regia in the middle of a thread about AP is really out of place and leads to confusion. I am proposing here to solicit comments only about the question being posed. When we get enough discussion I will pose the second question on the list so we can move forward on the same thread and in the end have a complete thread involving everything anyone needed to know about processing with AP.

So let's start with a list of scrap types that lend themselves to the AP process. Just list scrap types first, no processing steps, that will come next.

 

[Shark]

Anyone?

 

[FrugalRefiner]

Fingers, gold filled.

Dave

 

[Shark]

Stripped boards, gold filled, limited use for non magnetic pins. Some older, removable networking cards of the type used in older laptops. At times silver plated items.

I am understanding this as just list items that go into AP, and not how it is done yet.

 

[anachronism]

Materials that may practicably be processed using AP are:

Finger edges.
Pins (older.)
Top hats.
Gold plated telecoms connectors.
Processor legs/lids.
Older gold plated boards.

From a practicable perspective AP's uses for ewaste are in reality limited by yields, which shortens the list. For much of the visible gold in ewaste surface leaching of some kind is far better therefore it's very much a cherry picking exercise.

 

[Shark]

So let's start with a list of scrap types that lend themselves to the AP process. Just list scrap types first, no processing steps, that will come next.

Just a reminder of what is needed for this thread.

 

[4metals]

I guess this list will have to do next we can proceed to depopulating boards. If any latecomers read this and want to add a new scrap-type, PM me and I will edit it in. We are trying to do this in an orderly way.

 

[Martijn]

A big chisel helped me wedge up the plastic pin socket holders of PC motherboards, leaving the pins on the board. The same chisel was used to scrape off the pins and comonents.
I used a smaller chisel to cherry pick small processors, chips and mlcc's before scraping the pcb's clean.
A wooden block screwed to the workbench held the pcb's in place.
I covered the sides, back and top of the depolutation area with a large cardboard box to catch some pieces that flew away.

Handheld metal plate shears were used for the fingers, makes them curl and this prevent stacks of fingers closely packed to each other in the AP.

Relais, iron parts, transformers, aluminum hdd casings and heatsinks are separated for the scrapyard.

Hard disk drives and cd roms taken apart. Magnets are reused for all sorts of things.

 

[ssmontecarlo]

I see pins ( older)?.. what the difference. Some are magnetic some are not.

 

[4metals]

I see pins ( older)?.. what the difference. Some are magnetic some are not.

This older thread may help

 

[Shark]

I started by cherry picking the items that I know has a decent gold content and removing any steel, aluminum and all heat sinks. I group these into lots that can be processed in the same manner. Full plated pins I remove with heat, typically a small, pencil point torch. Heated the solder and banged the board on a plywood box which held the pins. Often removed any plastic housing first if I could bend the whole lot of pins enough to pry it off. Partially plated were often done the same way or hand cut with flush cut pliers leaving the non plated part on the board.

The remaining board I would heat with a larger torch with a flame spreader and remove the remaining parts in the same manner of knocking the board against another plywood box. Later separating more items by hand if needed.

Smaller boards such as memory, and slot cards, I removed all aluminum and steel, and/or copper and heat sinks. Again heating the whole boards and knocking components into the appropriate box for later processing.

Bare boards were separated into lots by gold, non plated boards separated for disposal and plated boards were bent drastically (enough to crack the protective coating, or broken into pieces, not smooth cut. If the mask won’t crack I rake a carbide saw blade sideways across them cutting into the mask enough to expose the metals underneath. The boards are now ready for AP.

I used a rotisserie oven with a basket wound on it and heat whole memory cards and most slot cards. As they heat the parts fall off into a pan. Usually took 2 to 3 minutes to strip memory and as much as 5 for slot cards. Again twisting or braking cards to expose the metals underneath.

Later I used a larger, home made version that could do full motherboards using a Forrest torch for heat, it was finicky and easy to over heat boards but doing 10-12 full sized boards at a time was quick. Needless to say quality, heat resistant gloves are a required.

 

[ssmontecarlo]

This older thread may help

Yes..I have a better understanding now.
Thank You..Be Safe.

 

[Shark]

Only three members using AP?

 

[Yggdrasil]

Only three members using AP?

I understood it as to add info if you have more of it.
Not to discuss the process in general.
And I have not ran boards only close cut fingers and pins.

 

[4metals]

Keeping in the order of processing we hope to maintain in this thread, the last step before the actual AP is removing any solder mask from the boards.
Let’s hear how you do it before moving on to the AP process.

 

[Yggdrasil]

Keeping in the order of processing we hope to maintain in this thread, the last step before the actual AP is removing any solder mask from the boards.
Let’s hear how you do it before moving on to the AP process.

I have not removed any solder mask.
There are times when I wish I had, but in general it will not be necessary.
At least not for close cut fingers.

 

[4metals]

At least not for close cut fingers.

Are close cut fingers a good scrap-type you would recommend as a starter lot for familiarization? Or possibly non magnetic pins?

 

[Yggdrasil]

Are close cut fingers a good scrap-type you would recommend as a starter lot for familiarization? Or possibly non magnetic pins?

I would think that close cut fingers are the easiest for the AP process.

 

[anachronism]

I would think that close cut fingers are the easiest for the AP process.

Simply put they are the easiest. Yes.

 

[Shark]

I agree cut fingers are the easiest.