# % of metal in CPU.



## MiltonFu (May 25, 2009)

Hello,
I am wondering if the percentage of metals vs ceramic (or fibre) has been determined during processing. For the purpose of this boards, I believe a 486 consists of approx 12% metal while a pentium pro is around 8.5%. A black fibre pentium should be over 20% metal. Perhaps there is more accurate information available.
I am trying to gauge the amount of metal in each type so that i can determine how much AR I need to dissolve my CPUs..
TIA.


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## butcher (May 29, 2009)

trouble is different metals, and you should eliminate base metals, before using aqua regia.


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## glorycloud (May 30, 2009)

butcher, is it true that the gold legs on most of the older 386 and 486 cpus
are 8K to 12K gold? I have read that somewhere "off forum" and I wondered
if that was correct.

If I had a small load of that type CPU's, would it be best to get the heat spreaders
off mechanically, then break them up a little and then AR them or would you still
recommend nitric first and then AR (after washing them to get the nitric off first)?


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## qst42know (May 30, 2009)

All CPU legs I have encountered have been magnetic for automated assembly. The plating, brazes, and some connecting wires, are what you are recovering. Many here have dealt with more and different types than I have though.


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## butcher (May 30, 2009)

I cannot give data on percentage of the metals, but eliminating base metals is a very important step before using aqua regia, they can create alot of trouble, very seldom would you recover metals with aqua regia, it is better used in refining the already recovered and fairly pure gold and platinum group metals, many of the other processes work great to eliminate the base metals and recover the gold and pgm's prior to using aqua regia, steves acid peroxide (copper chloride is one of my favorites), nitric, HCL, with and without oxidizers,
even electrorecovery with cells.

remember Inceneration a great tool. used it can mean the difference in sucsess or failure.

if lead and tin is involved you should deal with them first, HCL.(acid peroxide can be used here also ) lead chloride is pretty insoluble (lead chloride powder is slightly soluble in boiling water)
silver chloride is fairly insoluble (not soluble in boiling water) these are the tools for seperating silver and lead chlorides.
now if silver, Pd, and other base metals, we cant go staight to nitric even if we wash our product (would make week aqua regia from left over HCL and dissolve our values) so prior to using nitric we must incenerate of any residual chlorides, then we can use nitric to get silver and palladium.

now with a few washes our metals we want are fairly clean and recovered so we can go towards refining,

we can use HCL/ bleach cheap and easyier to recover our gold (if you are not used to the ridding nitric from aqua regia which for many people is a problem they still have not mastered).
or we could go for aqua regia , if your solutions are not yellow and are greenish you will probably have to refine your gold a second time, nitric in solutions will not let you precipitate the gold. 

when I do cpus I recover gold from pins first, then break them and recover again, then powder them and get the last bits, this may be more time than you want to spend? so could just powder them to begin with but they are more dificult to powder and powders are harder in my opinion to leach and filter etcetera.
if you understand the principles of the metals and the acids, you can develop stratagy how to deal with them, this is were I spend my study time on learning, to get the values.
Hope this helps.


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## glorycloud (May 30, 2009)

Great info! Thanks for taking the time to spell it out for me!!

This is what I hope to attempt to process unless I decide to become a "collector of antiquities" :


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