How do I deal with lead and tin from computer boards

[bklopsy]

Recently got my hands on alot of 1950's military aerospace boards. The fingers are so heavy you can really feel their thickness. There is alot of gold on these boards. I've tested. The wiring from fingers and to all other points on the board are thick. The board reads "Autonetics U S. There is nothing on these boards but the fingers, wiring and solder.

I am thinking to submerge complete board in AR: perhaps I'll cut it into pieces. It is 2 1/2" x 8" in size at present.

I have been conducting Steve's peroxide solution on another pound of cut fingers from a modern day computer. Unfortunately, they have been soaking in that solution for 6 days with very little sign of fingers falling off. I agitate twice a day and have added peroxide to muratic twice. So I wish to research AR as option. I live in CT and we have been in the mid 20 - 30s this last week so I do recognize this as a variable slowing down the process

Regardless, my question is, if I dissolve in AR, how do I deal with the removal of lead and tin from Gold solution?

I started Hoke's book Friday evening and am really engrossed but there is no addressing of solder.

I am open to suggestion

 

[Anonymous]

I usually take a box cutter and score down the middle of the fingers to allow the acids to start to leak in faster.

On the pins, best thing for me is to shear the pins off and keep as much as the solder as possible out of the process.

Most say not to use AR for recovering the gold from computer scrap and I ten to agree, although it sometimes takes time the AP or nitric acid processes are best as they help to keep the base metals to a minimum.

Jim

 

[bklopsy]

Hey Jim

The issue with these boards is that the fingers as well as all wiring is thick gold. The wires are nearly equal in size to the fingers. I've never seen so much heavy gold on a board before. these are vintage and built of the highest standard.

There is more gold on the boards combined, then the fingers!

 

[bklopsy]

You made me think. Why is it suggested not to do computer scrap in AR?

 

[samuel-a]

can you post a picture?

maybe it will be better for you to cut the fingers and process them alone.

 

[bklopsy]

I will have to post picture tomorrow. Having a doo-doo moment with new cell and unable to load software onto my computer.

 

[Harold_V]

You made me think. Why is it suggested not to do computer scrap in AR?

A straight ahead answer?

Because it's stupid.

What are the advantages?

With rare exception, I can think of none, but the hazards are all too clear.

Any time you dissolve base metals along with values, you risk losing values because of incomplete digestion. I shudder to think of how much gold has been tossed with the garbage by folks that refuse to use acceptable processing procedures, thinking they have the answer, when they don't have.

If the reason for not using AR to process copper and copper based alloys escapes you, you should go back to the books and read more, until it makes sense to you that such a process is not in your best interest.

If, after more study, it still doesn't make sense to you, may I suggest you find something different to occupy your time? That, to me, would be a clear indicator that you don't understand the refining processes well enough to keep out of trouble.

Harold

 

[Anonymous]

Hey Jim

The issue with these boards is that the fingers as well as all wiring is thick gold. The wires are nearly equal in size to the fingers. I've never seen so much heavy gold on a board before. these are vintage and built of the highest standard.

There is more gold on the boards combined, then the fingers!

If the plating to so thick and there is so much you may have to shear the pins and wires off, then grind the pins and wires up, then treat with AP, or Nitric. AP will dissolve tin and if there is lead it will be removed and some will dissolve the rest will be a powder type stuff that you can usually get rid of by boiling water.

Not having seen what you have, you should consider that any plated part that is soldered will have gold dissolved in the solder.

Jim

 

[glorycloud]

Read up about the use of nitric acid and aqua regia. When you use one
and under what conditions (metals being present) you use the other.

The first step in processing is really about developing a plan of action,
especialy when going for gold and PM's in e-scrap. Seperate the gold bearing
items away from the rest of the board as much as you can and keep like things together
like gold fingers, pins, CPU's etc. when processing. I don't process whole
boards as there are metals and other compounds that I don't want to mess
with. I go after the easy stuff and sell the rest of the board to Mr. Board
Refiner.

I know that you are new here and that it is hard to be patient when you
are getting started. STOP! SLOW DOWN! STUDY! Then proceed with
caution and with a plan in place for each type of escrap that you wnat
to remove the gold and other PM's from.

 

[bklopsy]

Jim and Glorycloud

Thanks guys

 

[bklopsy]

Going back to my batch fingers that I have been soaking in Peroxide/Muratic for six days. What else can I do, if anything, to excellerate their falling off the fiber board?

 

[butcher]

agitation, stirring, an air bubbler from an aquarium pump can help add oxygen and agitate, heat can help but if too hot can drive off acid,

main thing to be success is patients.
:lol:

 

[hemicuda]

I read a page in Hokes book in regards to solder.

It all starts on page 65 and continues from there.

I to am dealing with 30 + pounds of pins with solder on them as well.
But with anything,reading,understanding,patience,persistence and time will help!
Good luck.

 

[bklopsy]

Hemicuda and Butcher

Thanks guys. I will read that section this evening, Thank you. Butcher, I like your idea of a pump.