Incineration question?

[lunker]

Hello all,

I have had a friend incinerated some plated parts for me. They were palladium pin boards out of old IBM computers. And also a large pile of gold plated connectors.After crushing and sifting i have noticed that the plating has seem to have vanished. By that I mean the palladium plated steel have turned black and the gold pins have gone a dull gray. Is it possible that I have incinerated the wastes at to high a temp? I beleve they were roasted at around 800c for about three hours.Was the palladium oxidized? Gold vaporized? or could the combustion by products strip off the plating? Any insights would be appreciated.

best regards, Scott.

 

[Platdigger]

Most likely because of the thinness of the plating, and the lower melting temp of the base metals that, at these temps the pms have aloyed with the base metals.
Making recovery more dificult, in that now, all the base metals will have to be disolved to recover the presious ones.

 

[lunker]

The parts were quite thick and were intact when I crushed them. i was wondering if there are combustion by- products that could "Strip" the values from the wastes. also water is used to adjust the operating temps. I wondered if the water vapour could mix with the combustion gases to create compounds that could dissolve precious metals.

 

[goldsilverpro]

This is typical. All of the gold should still be there. The extreme heat causes the base metals to migrate up through the gold plating and discolor it. It doesn't really form a true alloy. If you dissolve the base metals in nitric or HCl/peroxide, the gold should remain as a powder.

 

[lunker]

Thanks for the reply GSP.It is greatly appreciated.