Processing Iron Wires from inside of IC chips

[FrugalRefiner]

White powder in AP can be a number of insoluble chlorides, quite often copper(I) chloride (CuCl). If it's CuCl, HCl will dissolve it.

I wouldn't worry about the bits of solder mask. When you dissolve your values, they can be filtered out before you reduce the gold.

Be extremely careful with NaOH, especially when it is hot. A full face shield is an absolute requirement. Don't get your hopes too high for the plating on cards and motherboards. It's still just plating, and is often thinner than that on fingers.

Dave

 

[Tzoax]

Thank You Dave. Very helpful. I noticed that on the surface of plastic bottle where I hold AP solution the small particles of gold are sticking, and is very hard to stick them off. I saw this before even when I used a glass bottle. Do You maybe know how to stick them off of the bottle? Does heating of the solution helps?

 

[FrugalRefiner]

I've not had to deal with that problem. I believe GSP has mentioned using a small piece of a Scotch-Brite pad to remove gold that is stuck to plastic. You can try an advanced search for that with goldsilverpro as the author.

Dave

 

[Barren Realms 007]

Thank You Dave. Very helpful. I noticed that on the surface of plastic bottle where I hold AP solution the small particles of gold are sticking, and is very hard to stick them off. I saw this before even when I used a glass bottle. Do You maybe know how to stick them off of the bottle? Does heating of the solution helps?

If you raise the liquid level above the foils they should dislodge from the side of the container in time or just a gentle shake after they have been in the solution for a while should allow them to release.

 

[Tzoax]

Thank You all very much.

I will continue tomorrow to boil the wires in HCl and I think they will be dissolved after couple of days since I am limited to boil them 4 hours per day. So far the half of wires dissolved.

 

[ahmadbayoumi]

Also, it would be nice to have an idea of yield numbers. Once I dissolved a hand full of those wires and didn't find anything precious in it...probably because I was way too much more a beginner in refining than today. Dissolving kovar takes a lot of acid and time, so I wonder, if it is worth any greater effort...

There is nothing "in" them. Amount of gold on these pins goes down to incineration and grinding. If done properly not much of gold can survive to stay attached to tip of a pin. I do not say you can remove everything but when done properly, amount of gold left on tip - rather bits of gold solder do not warrant heavy use of chemicals, recovered gold is not going to cover cost associated with doing that.
I have mentioned it several times, I use simplest method possible. I toss them in bucket of sea water or just water with handful of salt and splash of HCl (like 50ml). It take time but they will rust away eventually. I am down to about 40% of my initial-first batch and it did not cost me anything. I occasionally swirl water around, break lumps with rod. Pour off rusty water and top up with fresh one.

Very Interesting method Pat

But how much time it takes for ` pound of these metallic legs to get rid over the kovar ?

Also, after removing all rusty water, will you directly to AP for getting the gold ?

 

[patnor1011]

Try not to decant any solids, only red rusty water. Incinerate, I would use warm Nitric on residue, it may contain Ag/Pd, it will dissolve copper too. Then AR on the rest.

 

[ahmadbayoumi]

Thanks Pat

Then this would be the steps:

1- Put these metallic pins in bucket of sea water or just water with handful of salt and splash of HCl (like 50ml). It take time but they will rust away eventually.

2- Pour off rusty water and repeat till no more red rusty water

3- Incinerate; and this is to remove any traces of HCL

4- Put warm Nitric on residue, to dissolve Ag/Pd, and Cu as well

5- Go for AR

Correct me if I'm wrong PLS.

 

[patnor1011]

That is the plan. Normal water will do the trick I just use sea water as I do have plenty around and it make things rust faster. But be prepared that this stage will take many months. I am ok with that since it does not cost me anything.

 

[ahmadbayoumi]

Many thanks Pat 8)

I can also wait as there's no cost :lol:

But if for any reason I want to speed up the process, I can still boil the whole bunch in HCL

 

[Tzoax]

There are some pictures from yesterday boiling in HCl. So far I boiled for about 16 hours overall. Right now I am continuing to boil the wires. This is a very hard to dissolve.

 

[Smack]

Is that a jar your using for that reaction?

 

[Tzoax]

Is that a jar your using for that reaction?

No, it is Erlenmeyer flask with plastic cover to minimize evaporation.

 

[kole55]

There are some pictures from yesterday boiling in HCl. So far I boiled for about 16 hours overall. Right now I am continuing to boil the wires. This is a very hard to dissolve.
View attachment 2
View attachment 1

GREETINGS! Maybe it's better to put in table salt mixed with water and add acid (HCl) as the patnor proposed, and leave for a long time. I mean, I do not seem to be worth it to spend electricity, because there might not be a lot of gold and has a lot of metal. Yet this is just my opinion and thanks to private messages and for help!

 

[Tzoax]

I noticed that now (after 20 hours of boiling overall) there is a silver color layer of powder that doesn't seem to get rusting or even dissolving. There is a more and more of this powder every time I finish boiling. I guess that there must be a silver and palladium and other undissolved metals and that eventually when the dissolving of base metals is done, there will be only this kind of powder left. I still can not see not a single gold bonding wire, they seems to be still covered with rust or some sort of plating.

 

[richard2013]

hello Tzoax,

What about separating the powder as of this time, then proceed with washing and refining with the powder. If at this time an outer layer of base metals have been already consumed by the 20hrs boiling, then PM's on top of that layer must have already fallen into that powder seen in the pictures.

Then process the remaining undissolved pins, wash, refine then the output will be compared if the yield of the first powder being processed.After that we could tell if it is worth to proceed after 20hours of boiling..

 

[Tzoax]

There are some pictures from yesterday boiling in HCl. So far I boiled for about 16 hours overall. Right now I am continuing to boil the wires. This is a very hard to dissolve.
View attachment 2
View attachment 1

GREETINGS! Maybe it's better to put in table salt mixed with water and add acid (HCl) as the patnor proposed, and leave for a long time. I mean, I do not seem to be worth it to spend electricity, because there might not be a lot of gold and has a lot of metal. Yet this is just my opinion and thanks to private messages and for help!

Thank You Kole, it is a cheaper method, and I will store the wires in that solution as I collect them. I am doing this test to get some practice and to find out the yields of mainly gold, then silver and palladium.

 

[Tzoax]

hello Tzoax,

What about separating the powder as of this time, then proceed with washing and refining with the powder. If at this time an outer layer of base metals have been already consumed by the 20hrs boiling, then PM's on top of that layer must have already fallen into that powder seen in the pictures.

Then process the remaining undissolved pins, wash, refine then the output will be compared if the yield of the first powder being processed.After that we could tell if it is worth to proceed after 20hours of boiling..

Thank You Richard, interesting idea, but i don't know how to separate the powder and wires, and even if I could, some of the golden bonding wires would still be attached and mixed with rest of the wires. The golden bonding wires keeps the form of itself since it is made by pure gold and is very hard to separate them from the rest of the wires.
I will follow the Kurt's advice and will treat them as he described. So far I boiled the wires 24 hours and the reaction is getting slower.

 

[MicheleM]

Dear all ,
Interesting thread, I read that in some IC packages even the external metallic legs can have a Ag/ Pd plating too:
https://www.shinko.co.jp/english/product/package/leadframe/ppf.php
Just as experiment , I am going to see if my barren solution (HCl+ potassium salts+ a very small quantity of H2SO4 and metallic impurities) is able to corrode more quickly the base metals of the magnetic pins and the leadframes.