samuel-a
Well-known member
- Joined
- Oct 7, 2009
- Messages
- 2,190
This method is also known as wet ashing, a highly dangerous process which should only be attempted by an experienced operator, with all of the proper safety gear and apparatus.
Otherwise, DO NOT follow this process !
----------------------
Jaun Nailed it in this post: Black IC's - a look inside
Since the method i used was unveiled and is indeed a very dangerouse process, i decided to share the entire process that i did, both to unveil the 'mystery' and make sure anyone trying this will keep himself SAFE.
The background to this process.
I my post, i said i had an: "ah ha moment"...
I was sitting in my lab and looking at my plastic buttle of conc' H2SO4, when i bought it, it was white, after several monthes it got very dark inside, that was the moment i remembered someone here on the forum mentioned that conc' H2SO4 strip the plastics off its elemental composing atoms, only to be left with black carbon, which gives this dark color.
At the time, i was busting my had around the black plastic type packages IC's and how to process them...
That was me 2+2 moment, since i have done wet ashing before with old filter papers...
So, i figured, if it takes couple months to "ash" the plastic in the buttle... imagine how fast will a HOT acid work...
I began experimenting and this is the process i came up with:
- IC's are covered with Conc' H2SO4 and the vessel is covered with watch glass (or condensation apparatus).
I came to learn that for each pound of IC's, i'll need a approx 1 liter of conc' acid.
Solution level should not exeed half the volume of the vessel !
- Slowly heated to 90° C (194° F) and left that way for 30 minutes.
This is a precautionary step to prevent too violent reaction and maybe a boilover.
The epoxy resin (Bismaleimide-triazine epoxy) will begin to disintegrate alsmost immediately.
- Then, heat is ramped up to 240°-250° C (464°-482° F) for one hour.
At which point, white Sulfur Trioxide fumes are noticble. I don't think i need to mention HOW DANGEROUS SO3 gas is. It is one step away from becoming sulfuric acid, all it needs is water, it can find them in you mouth and lungs!
The solution at this point is a black thick slurry and very hard to actually see any reaction, but it's happening.
- The solution is allowed to cool back down to ambient temp' while still on the hotplate (do not handle it while hot, reduce the risk of a mishap), this takes a good 2-3 hours.
At this point, all that's left in a solid state (other then carbon in a slurry and colloid form) are metals such as gold (wires), the silicon waffer and copper "skeltons" (in case memory chips are processed). I'll address that later.
- Slowly and carefully, water is added to the acid to double the volume.
I know what you are thinking, but, At this point, there's very little acid left to react with the water, but of course you can choose to do so the other way around.
Once diluted, is allowed to sit for 5 minutes or so.
- The bulk of the slurry is decanted slowly to a 5 gallon bucket, carefully leaving anything that had setteled in the vessel.
The process of dilution and decantation is repeated until all of the black carbon slurry is gone.
Of course, you will notice the gold wire, it's impossible not to!
Most of the wires will stay attached to the waffers, those that come loose, will quickly agglomerate. BUT, some will still be left to fly around, they do settle, but you must give them the chance to do so. This is why it is instructed to wait before decantation.
If you see any partially dissolved IC's, fish them out with a tweezers, wash them and throw to the next batch.
- The next step is dependant on which type of IC chips were processed.
In the case of N/S bridge and square IC's:
Mostly silicon waffers and gold wires are left, direct AR / HCl-Cl could be used.
In the case of memory chips, there will be a lot of copper along side the waffer/wires.
One can eliminate the copper with nitric acid or AP.
I chose to melt everything down to form a Copper anode.
Jaun mentioned in his post that he successfully used conc' Nitric acid, I find it a little bit scary, for even the slightest chance of producing an explosive compunds.
I might be wrong of course, but whan you think about it, hot conc' nitric is just as dangerous and can cost 5-10 times more then the sulfuric does.
I was very reluctant to discluse this process before due to 2 main reasons (never had inentions on selling it):
The first, is the obvious direct danger of utilizing boiling sulfuric acid...
i can't stress the safety issue enough.
Eye protection or a full face mask should be used while handling.
Long chemical resistand gloves should be weared at all time.
The process should be done in a fume hood or out side away from peoples and pets.
Extreme care sould be enforced while handling conc' H2SO4.
A bucket of sodium bicarbonate is recommended to have around, just in case.
The second reason, is the indirect waste hazareds.
As you probably realized earlier, this process produce a fair amount of of waste solution, one lb of chips may create up to a gallon of waste.
I consulted with two very smart folks on this subject, both of which holds a degree in chemistry (Lino1406 ans sucho).
We all concluded that the resulting waste solution will probably not hold any toxic organic/organosulfur/aromatic compounds and can be safely discraded to the drain.
The only treatment step that i do think should taken in this regards, is to place a sheet of steel to displace any Cu in solution.
Any input from you on the waste solution subject is more then welcomed.
I know this process can help A LOT of peoples here, but PLEASE, use all the safety measurements mentioned above.
It's not worth to loose the palm of your hand, your foot, sight or even your life for so and so grams of gold.
Hope this helps, DO share your thoughts, comments and experience.
----------------------
This method is also known as wet ashing, a highly dangerous process which should only be attempted by an experienced operator, with all of the proper safety gear and apparatus.
Otherwise, DO NOT follow this process !
Otherwise, DO NOT follow this process !
----------------------
Jaun Nailed it in this post: Black IC's - a look inside
Since the method i used was unveiled and is indeed a very dangerouse process, i decided to share the entire process that i did, both to unveil the 'mystery' and make sure anyone trying this will keep himself SAFE.
The background to this process.
I my post, i said i had an: "ah ha moment"...
I was sitting in my lab and looking at my plastic buttle of conc' H2SO4, when i bought it, it was white, after several monthes it got very dark inside, that was the moment i remembered someone here on the forum mentioned that conc' H2SO4 strip the plastics off its elemental composing atoms, only to be left with black carbon, which gives this dark color.
At the time, i was busting my had around the black plastic type packages IC's and how to process them...
That was me 2+2 moment, since i have done wet ashing before with old filter papers...
So, i figured, if it takes couple months to "ash" the plastic in the buttle... imagine how fast will a HOT acid work...
I began experimenting and this is the process i came up with:
- IC's are covered with Conc' H2SO4 and the vessel is covered with watch glass (or condensation apparatus).
I came to learn that for each pound of IC's, i'll need a approx 1 liter of conc' acid.
Solution level should not exeed half the volume of the vessel !
- Slowly heated to 90° C (194° F) and left that way for 30 minutes.
This is a precautionary step to prevent too violent reaction and maybe a boilover.
The epoxy resin (Bismaleimide-triazine epoxy) will begin to disintegrate alsmost immediately.
- Then, heat is ramped up to 240°-250° C (464°-482° F) for one hour.
At which point, white Sulfur Trioxide fumes are noticble. I don't think i need to mention HOW DANGEROUS SO3 gas is. It is one step away from becoming sulfuric acid, all it needs is water, it can find them in you mouth and lungs!
The solution at this point is a black thick slurry and very hard to actually see any reaction, but it's happening.
- The solution is allowed to cool back down to ambient temp' while still on the hotplate (do not handle it while hot, reduce the risk of a mishap), this takes a good 2-3 hours.
At this point, all that's left in a solid state (other then carbon in a slurry and colloid form) are metals such as gold (wires), the silicon waffer and copper "skeltons" (in case memory chips are processed). I'll address that later.
- Slowly and carefully, water is added to the acid to double the volume.
I know what you are thinking, but, At this point, there's very little acid left to react with the water, but of course you can choose to do so the other way around.
Once diluted, is allowed to sit for 5 minutes or so.
- The bulk of the slurry is decanted slowly to a 5 gallon bucket, carefully leaving anything that had setteled in the vessel.
The process of dilution and decantation is repeated until all of the black carbon slurry is gone.
Of course, you will notice the gold wire, it's impossible not to!
Most of the wires will stay attached to the waffers, those that come loose, will quickly agglomerate. BUT, some will still be left to fly around, they do settle, but you must give them the chance to do so. This is why it is instructed to wait before decantation.
If you see any partially dissolved IC's, fish them out with a tweezers, wash them and throw to the next batch.
- The next step is dependant on which type of IC chips were processed.
In the case of N/S bridge and square IC's:
Mostly silicon waffers and gold wires are left, direct AR / HCl-Cl could be used.
In the case of memory chips, there will be a lot of copper along side the waffer/wires.
One can eliminate the copper with nitric acid or AP.
I chose to melt everything down to form a Copper anode.
Jaun mentioned in his post that he successfully used conc' Nitric acid, I find it a little bit scary, for even the slightest chance of producing an explosive compunds.
I might be wrong of course, but whan you think about it, hot conc' nitric is just as dangerous and can cost 5-10 times more then the sulfuric does.
I was very reluctant to discluse this process before due to 2 main reasons (never had inentions on selling it):
The first, is the obvious direct danger of utilizing boiling sulfuric acid...
i can't stress the safety issue enough.
Eye protection or a full face mask should be used while handling.
Long chemical resistand gloves should be weared at all time.
The process should be done in a fume hood or out side away from peoples and pets.
Extreme care sould be enforced while handling conc' H2SO4.
A bucket of sodium bicarbonate is recommended to have around, just in case.
The second reason, is the indirect waste hazareds.
As you probably realized earlier, this process produce a fair amount of of waste solution, one lb of chips may create up to a gallon of waste.
I consulted with two very smart folks on this subject, both of which holds a degree in chemistry (Lino1406 ans sucho).
We all concluded that the resulting waste solution will probably not hold any toxic organic/organosulfur/aromatic compounds and can be safely discraded to the drain.
The only treatment step that i do think should taken in this regards, is to place a sheet of steel to displace any Cu in solution.
Any input from you on the waste solution subject is more then welcomed.
I know this process can help A LOT of peoples here, but PLEASE, use all the safety measurements mentioned above.
It's not worth to loose the palm of your hand, your foot, sight or even your life for so and so grams of gold.
Hope this helps, DO share your thoughts, comments and experience.
----------------------
This method is also known as wet ashing, a highly dangerous process which should only be attempted by an experienced operator, with all of the proper safety gear and apparatus.
Otherwise, DO NOT follow this process !
