My latest project.

[Moo]

Hi boys and girls

I intend on processing some flatpacks using patnors method, . probably about 15 kilograms ( 30+ lbs) just to make sure its worth the time doing. Before proceeding I figured it might be wise to dunk all of these in HCL for a few days to remove what base metals there are around the outside of the chips.

I ran a small, batch through hcl for a few days and today I filtered off the black solution, I noticed however some base metals remain on some of the ram chips It looks like copper to me but im not completely sure.

I was considering that I could get rid of this remainder using either nitric or AP.
What would be the best way to do this? If its just a difference in time and I could use AP rather then nitric Id prefer doing it that way.
When it comes to pyrolysis time I plan on sitting them all in a steel pot replacing the lid and burying it in hot coals.

Can the north bridge chips be crushed as a whole or should I remove the tops first?

If any experienced member can see a problem with how I plan to proceed with this please kindly advise me before I tear out the little hair I have left

 

[butcher]

HCl alone will not dissolve the copper, going to nitric now you may create some aqua regia (we do not want to put gold into solution at this point).

The copper II chloride leach (acid peroxide HCl / 3% H2O2 ) at this point is the best choice, given a little time or some heat, it will dissolve the copper legs off of the chips.

You could leave the copper legs and separate the copper and gold later after you remove the ash.

Since these have been soaked in a chloride solution, before incinerating (or burning the chips), I would give them a wash in a mild NaOH solution, neutralizing this wash to pH 7 and rinse well in hot water to dissolve any NaCl salt that forms, when gold is heated with chlorides up to around 800 degrees the gold can form gold chlorides (if chlorides are involved). At this temperature the gold chloride is volatile and you would lose gold in the fumes of the process.

 

[Moo]

Hi Butcher thanks for the great advice mate, never would that have occurred to me. So to proceed my plans will be.

1. After removing all the base metals soluble in HCL, Place all chips in a solution of AP until all the copper is removed.
2. Bath the chips in a mild solution of NaOh for a few days bringing the Potential Hydrogen to neutral to be sure any chloride ions are deionized.
3. Proceed with incineration.
Can the north bridge chips be crushed as a whole or should I remove the tops first, Im assuming I should remove the tops?
I hope Ive got this correct. Thanks very much for your help

 

[Pantherlikher]

Moo.
Aren't you taking Extra unneccesary steps? You would still have base metals after pyrolizing and have to deal with them again so why do it twice?
BS.

 

[etack]

Pyrolysis makes charcoal. you want to incinerate to white ash.

I dont think its a waist of time I would use poormans AR this removes most of the annoying magnetic legs.

Eric

 

[maynman1751]

If you already have the chips in HCl, just add H2O2 and you have AP....add a little heat and air. Yes, you should separate the tops from the bottoms and process them separately. North/south chips should be processed by themselves. I wouldn't mix materials. Just my opinion!

 

[Moo]

Thanks for all the advice people, Maynman why do you process n/s chips separately?

 

[maynman1751]

I myself have never processed n/s chips yet. But it has been suggested by the more knowing members to process like materials separately. All materials react differently to processes, so it is better to keep like materials together. You generally would not process say foils with pins or cpu's with fingers. That is my understanding.

 

[g_axelsson]

You should rip apart the BGA packages so you get the plastic top with the bonding wires separated from the small green circuit board base.
The top part is best processed separately from the rest of the flat packs until after the incineration at least. In normal flat packs there are no bonding wires exposed outside of the capsule so during incineration there is no danger of tin melting and dissolving exposed gold. But in the BGA tops there are bonding wires exposed that you risk dissolve in molten tin.
When you are at the panning stage when the large metal parts have been removed there isn't any advantage to keep the material apart any longer and then you can mix it.

Just a disclaimer at the end, I haven't tested recovery from flat packs yet, I've only done an incineration of a BGA chip once to test some theories. So you better double check my theories with some one else.

/Göran

 

[rheslin2]

Great thread

i have been doing the tops this way for a few months now, and have had both, good luck and fun doing it, however...... i now have a large pile of the green bottom parts of the chip, and have not found an effective way to do them. any suggestions for the green board part of the chip?

bob

 

[Geo]

remove the solder with hcl and either AP or straight AR.

 

[Moo]

Thats one heck of a chip heres mine after a few days in HCL they just peeled apart.

 

[Geo]

a few days? what were you trying to do? if you were trying to remove the solder, it only take a matter of minutes (maybe fifteen or so) of heating in hcl to remove the solder. heating in copper chloride solution will work faster than bubbling air through it but you can only do a small amount that way at a time.

 

[Moo]

Killing off evil base metals and leprechauns seems there always killing my gold off lol

 

[patnor1011]

It is little bit overkill to soak them in any acid prior to incinerating. I mean you are spending resources and time and will get rid of no more than few % of base metals. Those legs extend all the way to the middle of chip where they connect to core silicone chip (using gold bonding wires).
I mean you will get rid of some metal but it is less than one tenth of base metals found in them. I would use straight nitric or poormans AR or AR - it is faster, much faster than HCl or AP.

I will separate s/n bridges by all means. They are cream of chips, there are no base metals or pins in there and centre piece can be easily fished out with some strainer (proper incineration advised so you do not need to crush them in some mortar and pestle device or ball mill).
Processing them is far more quick and easy comparing to all other flatpack chips. In all other you will have to deal with inside pins and metals and separate or dissolve those.