Gold inside chips (black, flatpacks - not CPU)

[nmlfreitas]

..... nitric wash is to remove the few copper legs and the small amount of silver/palladium in the glass chips. also, after the nitric bath, you may see some white material that would not dissolve in the nitric. this will most likely be bits of melted aluminum.aluminum is used under the packages substrate as a heat spreader.after the nitric bath, incinerate the powder to remove the nitrates. now place the powder into a hcl bath to remove the aluminum.after this wash, rinse with water and process with your choice of chemicals.

I think this will answer your question. First Nitric bath, you can read it in Pantor's guide, and after hcl bath...

 

[solar_plasma]

Thank you!! Now I see.

 

[patnor1011]

The process Patrick presented and discusses uses no chemicals except H20 for the recovery.

Yeah, I use chemicals on final concentrate obtained by washing ashes away with just water. Water and magnet will reduce incinerated material to about 10% of what you started with. Water is essential on keeping cost of recovery under control. No point to soak all incinerated ashes in acids. Do it on concentrate only.

 

[solar_plasma]

No point to soak all incinerated ashes in acids. Do it on concentrate only.

incinerating - washing/magnet - HCL - neutralizing - incinerating - HNO3 (Ag, Pd) - AR (Au, PGM)

I was just confused if first HCl and then HNO3 or first HNO3 and then HCl. Does the HNO3 dissolve AgCl or will Ag cement back on the copper,so it will be dissolvable in HNO3? I was just afraid of leaving any silver back in the mud. But now I have started with HCl.

EDIT: oops I did not realize that we are in the thread "Tutorials", I know there is not allowed to ask questions. Sorry.

 

[Geo]

ive always used the nitric bath first. this removes and silver before any other process. after this, any insoluble oxides should be taken care of with the following incineration and hcl bath. im not sure which way is better but i havent had any problems with insoluble salts. my problem is the finite dust that makes it through all the filterings. it has to settle until the liquid is clear every time the fine silt is disturbed.i truly am in need of a better filtering system.

 

[solar_plasma]

When I have finished, I will try to put some copper filings into the left over mud and see if there is some Ag cementing, which I dissolve in HNO3 and test by Cl-

 

[g_axelsson]

incinerating - washing/magnet - HCL - neutralizing - incinerating - HNO3 (Ag, Pd) - AR (Au, PGM)

I was just confused if first HCl and then HNO3 or first HNO3 and then HCl. Does the HNO3 dissolve AgCl or will Ag cement back on the copper,so it will be dissolvable in HNO3? I was just afraid of leaving any silver back in the mud. But now I have started with HCl.

If you are concerned with creating silver chloride and losing it, I would suggest a modification.

incinerating - washing/magnet - HCL - wash with NaOH solution - wash with water - incinerating - HNO3 (Ag, Pd) - AR (Au, PGM)

- I removed the neutralizing step between HCL and incineration, the incineration will evaporate off any acid residues.
- Added a NaOH wash step folllowed by water wash.

The NaOH will convert any AgCl into Ag₂O, then the incineration will decompose the Ag₂O into metallic silver and oxygen above 280 degrees C. No AgCl that can go up into smoke at the incineration step and all silver will be soluble in nitric after incineration.

Correct me if I'm wrong.

Göran

 

[solar_plasma]

Göran

wash with NaOH solution

Thanks! That's an ingenious advice! One problem solved.

You will probably have seen it, I have just done the opposite of what I was told and what I wanted, I ask HCl first or HNO3 first...everyone says: HNO3 first!....I say: Aaah, I see! First HCl.... :roll: :lol:
Well, well, ...but it sounds as if both will work. Next time I do as adviced.

 

[resabed01]

I am new to this and still learning but I'm of the opinion of HCL first before HNO3 just for the simple reason of getting rid of base metals first, especially tin which will cause you heartburn later. I know HCL can be painfully slow and HNO3 works much faster which is why, i think, some people prefer to use it first.

 

[Geo]

I am new to this and still learning but I'm of the opinion of HCL first before HNO3 just for the simple reason of getting rid of base metals first, especially tin which will cause you heartburn later. I know HCL can be painfully slow and HNO3 works much faster which is why, i think, some people prefer to use it first.

processing chips is a process in and of itself different from processing other scrap.by removing the magnetic material first, you are removing the solder.any remaining tin would be negligible.you can remove all the base metal at once except any aluminum. the aluminum is the reason for the hcl bath.

 

[rickbb]

Interesting, too bad I didn't find this a few months ago. I've been cutting the fingers off and trashing the rest of the cards/boards. Leason learned.

 

[solar_plasma]

If a person wants to learn how to build an airplane and learn to fly it, he would do best from learning from the mistakes of others that have tried for centuries to learn how build planes and to fly, and learn from these people who tried this before him, and can show him what works and what does not work, before he jumped of the cliff in the airplane he thought would be easier to build and to fly.

good example, since it was Leonardo da Vinci, who invented flying machines, when everyone else would have thought it to be a sacrilege. Now,he has never build them in real, but I saw a video, where they have build those machines exactly, like Leonardo invented them: they could fly! Science is not only a top-down (using existing theories) but also a bottom-up (empericism). I think development is only possible,if you get use of both, every existing knowledge and belief AND thinking outside the box. It's therefore teams of different characters can obtain a synergistic.

That is, what you are saying. I just lay the intonation the other way round.

 

[solar_plasma]

wow, this takes time! Now, I am washing off the NaOH from the second half of my batch. I used KOH for the first one, I don't know why, but KOH worked better and faster. The solids felt much faster to the bottom. First half is already incinerated. Should have done the whole batch at once, - I need a much bigger funnel! I guess, the silver chloride/oxide makes it slow (if there is any :lol: )

 

[solar_plasma]

you can remove all the base metal at once except any aluminum. the aluminum is the reason for the hcl bath.

I wonder....since it is only Al that has to be dissolved in the HCl step and there is no Sn, then only hot NaOH would do the same. (Caution: exotherm, will get hotter, etching fumes)

Advantage would be almost pure sodium aluminate as waste and pure waste is a resource. All the other base metals will dissolve in HNO3.

Another advantage would be, that the incineration would get unnecessary.

Soldered chips could be treated with HCl before crushed or incinerated, this would make the whole process much faster and less nasty.

...does anybody not confirm?

 

[solar_plasma]

...Then it comes on my to-do-list.

My advice to all new ones is ofcourse to do, like the very experienced guys on the forum do. Their methods work for sure and you can get help, if you meet some probs.

 

[solar_plasma]

Okay, I read on ofcourse and have deleted the last idea from my list, because:

http://goldrefiningforum.com/~goldrefi/phpBB3/viewtopic.php?f=37&t=15026

Aluminum should be dissolved in HCl
Iodine with Al - a mess
NaOH with Al - a mess

...and when Lino, my taciturn favorite chemist says, it is a mess, it must be a mess....

 

[alvaschein]

Hi all

I took my time for al little "research" on gold content of black chips. First I sorted a pile of black chips into more or less similar type classes. So at the end I had 16 different classes. From each class I took a sample of about 50 g, depending on how much I effectively had, treated them to get to the gold bond wires and calculated the ratio of gold content.
I have to say that the washing process without losing to much bond wires was rather difficult and there still remained some dirt of cracked silicone chips. So, I guess the resulting yield might be the maximum possible yield with this kind of treatment.

Well, take a look at the results (see attached doc) and calculate for yourself which type of chips is worth for hunting for. My personal favorites are the FCBGA's. They had surprisingly long bond wires.

Have fun

Roy

 

[Claudie]

Very nice!
Well laid out and easy to understand. A lot of time and work in this, thank you for putting it on here.

 

[solar_plasma]

An impressing piece of foundational research! Thank you very much!!!

 

[g_axelsson]

Thanks a lot! Fantastic work!

I just wish I had it six month ago when I sold a lot of chips...

:mrgreen:

Göran