My results of specific types of IC chips, flatpacks and BGA

[Tzoax]

If somebody want to refine ram chips, here is my finding. The chip with small epoxy area from the bottom its mostly flip chip technology. And the ram chips with larger epoxy area have gold bond wiring. If i am wrong, please forgive me. I just want to save yours hand. Sorry for my English.

Zoltan, thank you. I think that gold bonding wires are inside of epoxy...



...solder ball from image that you captured is used to connect two parts of IC chip....

....also there are Package on package (PoP) packages like in these pictures and solder balls you captured are used to connect upper and lower parts of IC(s).

 

[Tzoax]

When silver chloride settled down - solution was decanted into the charmin plug filter...and AgCl was "washed" with fresh HCl to collect all of the solution into the filter.

AgCl....



Filtered solution is clear and now is ready for adding SMB....



I added SMB and ---solution is becoming dark brown - gold is dropping down...

 

[Tzoax]

Dropping gold was slow - so i left it about 1 day to settle down.

Even it looks like there is much of gold - it is really a very thin layer of gold - if i point a light in reverse direction - it looks semi-transparent.






Now i need to remove solution carefully - decanting would "pull" some of gold with it - so i am using plastic syringe (without needle of course) in situations like this. I will carefully remove solution with syringe - and remaining gold powder will be ready for gold washing.

 

[Tzoax]

Gold powder after removing solution...



Washing gold powder with water/HCl...




Look of dried gold under magnifying glass...



It is very small amount of gold....

It is ready for weighting... i don't know what is minimum detection of weight on my scales...so just in case, i will add 1.00g of gold on scales and add this gold on top of that...to avoid not detecting it - it looks like pretty small amount of gold.

 

[Tzoax]

And here is result...

I added 1.00g of gold into beaker...



After adding gold powder...



So - result is 0.05g of gold out of 26.1g of ceramic resonators.

0.05 / 26.1 = x / 1000
x = 0.05 * 1000 / 26.1
x = 1.915

So, 1kg of mixed ceramic resonators have around 1.9g of gold.

*Since i made test with very small sample - result is not very accurate - but at least it can give some clue about yield.

Alex

 

[niks neims]

... The more you know

Thank you!

Whats next?

 

[cosmetal]

Alex,

Thank you for "biting the bullet" https://en.wikipedia.org/wiki/Bite_the_bullet for us with these ceramic resonators.

Your time and meticulous methods are always appreciated!

James

 

[Tzoax]

Thank you all for support... winter is coming - so i will spend much time doing my other hobby - programming. I have about 1kg of mixed kovar/copper wires from IC's - with some of gold bonding wires tangled between....so i have this idea how to separate them mechanically - with couple of electro-motors and USB microscope. I would make computer application that recognize gold color (gold bonding wires) and as soon it does - it will activate EM and separate gold bonding wires in separate container. Of course - some of kovar/copper wires will go through - but it can be repeated again....anyway - there is much more details...but here on this picture is my basic idea.

 

[FrugalRefiner]

Very much along the lines of sophisticated sorting I've seen in the food industry. Some of it operates at speeds beyond what the eye can detect. I'll be interested to see how it works for you.

Dave

 

[stella polaris]

How does the gold actually goes of the legs? Is the wire 100% complete or is a part remaining on the leg/dice?

 

[Tzoax]

How does the gold actually goes of the legs? Is the wire 100% complete or is a part remaining on the leg/dice?

After the incineration of IC chips - the gold bonding wires are coming off silicon dies and legs - in crushing stage.

But...some of gold bonding wires are tangled/meshed together with legs - so they are not coming through sieve - or they are still soldered to legs.

Many people are processing legs - to take out those remaining gold bonding wires and possible AG and Pd...
...but it is taking too much of acids and majority of gold is already processed before that stage (concentrate) so the yields will not be high - so it is question if that procedure is worth of time and chemicals.

I just checked out mu legs with magnifying glasses and the most of gold bonding wires i saw was not "free"-detached/tangled - but still connected to legs.

 

[stella polaris]

What about tumble the legs together with something that can knock of the wires? (no ball milling)
I can image that an old washing machine could be used for that. (adapted drum) Some bolts and nuts added to knock the wire of.

But perhaps some gold would still be remaining on the legs. Do the gold go of clean in the leg joint?

Edit:Worth a try to find out; Put legs in a larger pet bottle, add some bolts and put on some latino music. Shake loose and see if they come of.

 

[Tzoax]

What about tumble the legs together with something that can knock of the wires? (no ball milling)
I can image that an old washing machine could be used for that. (adapted drum) Some bolts and nuts added to knock the wire of.

But perhaps some gold would still be remaining on the legs. Do the gold go of clean in the leg joint?

That would surely help...but still - gold bonding wires tends to tangle with/around legs - especially longer gold bonding wires ... soon i will buy USB microscope and i will do some really good images related to this...
and i will inspect leg joints to check what remains on them when gold bonding wires are separated - that is also one of the thing that i am interested in --- are gold bonding wires just brakes - and leave some part of it still attached....or gold bonding wires are completely separated and leave only small gold residue. I will make experiment with gold bonding wires that are still attached to legs and i will separate each bonding wire at a time and observe (and make photos/videos) what is remaining on legs.

 

[stella polaris]

Do you have the feeling that they get so hard entangled that they do not seperate by shaking or vibration?

 

[Tzoax]

Do you have the feeling that they get so hard entangled that they do not seperate by shaking or vibration?

I don't have to got feeling about that - those wires i have now - had a pretty good multiple shake (inside a glass jar) and was sieved 3-4 times...and still here they are - gold bonding wires are still there - some are tangled and some are still connected to legs.

I think that using too much force (like washing machine with bolts) will be not so good idea because gold is very soft - and gold bonding wires could be "merged" to other metals so hard that it would be even more harder to separate them...but i could be wrong - i never tried that.

 

[stella polaris]

I have been thinking of this problem for some time. IC gives a lot of legs and i do not want to spend acid or cut them of. Maybe a small fraction of sharp quarts would do the job better than bolts. ( cheap and easy to deal with) Then pan the gold out.

 

[patnor1011]

If force is applied and some bolts and stuff then some wires will get smeared on pins.
I think that the best approach will be some leach to go after gold only. Dissolving pins is going to cost too much in resources used and time.
I suggest cyanide leach as that may be the fastest and cheapest method to tackle pins.

 

[stella polaris]

If force is applied and some bolts and stuff then some wires will get smeared on pins.
I think that the best approach will be some leach to go after gold only. Dissolving pins is going to cost too much in resources used and time.
I suggest cyanide leach as that may be the fastest and cheapest method to tackle pins.

Cyanide leach is a good one. But were i live and on the scale i will recover gold it is not the easiest.

Tricky to get hold of. Tons of regulations and a hazard involved (Cyanide). Personally I would prefer a mechanical solution.

When i say tumble it should not be confused with ball milling. I mean a slow, gentle movement that would shrubb the gold of. Perhaps even with water added to slow things down.

The idea of bolts was that the helical ridge would scrape the gold of. Not hammering nor cruching as if fast or longer distances of falling involved. It simply must be needed less force to cut or scrape the gold of than to smash it into the legs so hard it would stick. (Bended around the leg is an other problem i do not consider here)

The bolts or screws used should preferably be without head and quite small. This to expose maximum of ridge. Then, during a slow gentle tumbling, these ridges would scrape the gold of. A non noisy operation.

Quarts could be an other option. A sharp quarts sand could cut of the gold. Later to be recovered by panning.

Think a slow moving washing machine. If the gold get smashed then lower the speed and use smaller bolts/screws. Adding water could defently be an idea.

 

[rickzeien]

Maybe a rock tumbler/polisher would do the trick. The sand Idea sounds like it might work.

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[stella polaris]

Maybe a rock tumbler/polisher would do the trick. The sand Idea sounds like it might work.

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rickzeien you understand what I am thinking of. I started to be worried :lol:
What about this?

Leg/quarts sand mix (+ water?) Then add a concrete vibrator or other type of vibrator.