# Unknown metal after drop



## Marcel (Oct 7, 2012)

I used copperpowder to make a precipitation of a solution from MLCCs residues that were left over after boiling them in hot HCl.
I expected silver, but received a unknown substance which I either hold for a mix of leftover copper + X or something else that should be above silver in the electrochemical order.
It is meltable, but took very long an two torches plus oxygen. While melating I saw small spots of gold and some red metal in it.
It does not react to HCl, barely to hot HCl and hot HCl plus H2O2 give digests all substance giving me a light yellow-greenish solution..
Can someone help me out with this?
step 1


step 2


step 3


step 4


step 5


----------



## samuel-a (Oct 7, 2012)

Marcel said:


> It is meltable, but took very long an two torches plus oxygen. While melating I saw small spots of gold and some red metal in it.
> It does not react to HCl, barely to hot HCl and hot HCl plus H2O2 give digests all substance giving me a light yellow-greenish solution..



What does SnCl2 test looks like on that solution?


----------



## butcher (Oct 7, 2012)

Not from your description of how you got to this point but from the pictures (it looks like iron to me).

After trying stannous read Hokes page 100.


----------



## etack (Oct 7, 2012)

Marcel said:


> from MLCCs residues that were left over after boiling them in hot HCl.
> I expected silver



You shouldn't have any Ag in solution if you digested id HCl.


Eric


----------



## butcher (Oct 7, 2012)

In the jar it looks to be a copper powder, contaminated with a gray substance, what is baffling me is this just a waste solution of HCl and are those circuit boards in the bowl, could this be lead chloride mixed with the copper powder or possibly Pt, Pt, and lead mixed in copper powders, but I do not understand if these PGM were dissolved into solution and already precipitated out of solution is this was just the remaining solution you are trying to precipitate missed values from using copper powder, or if these valuable metals were left in solution up to this point and your trying to cement them out on copper

MLCC's capacitors I would not think had iron involved, but would have lead and tin if de-soldered from circuit boards, circuit board could have iron if not removed and would precipitate copper.

The things in the bowl in your pictures look too big to be these small capacitors, and this is the reason I was thinking circuit boards were in solution, also it does not look like copper dissolved much or very well into solution, no oxidizer in HCl solution, or an high excess of copper powder used.

Well I guess I need a better understanding of what was put into solution up to this point, and what was removed from solution and how, otherwise I feel like I am in a guessing game without any clues.


----------



## Marcel (Oct 8, 2012)

@sam: Stannous chloride is the same color as the green in the picture but lighter. (I assume the "whiteness" comes from silverchloride?)
@butcher: I tend to think what you said that there is a lot of undisolved copper plus the very few precipitated PMs mixed.
Those objects in the jar are copper sheets that I placed there. 
The MLCCs were put in a net (one that you use for catching small fishes) and so I was able to completly remove the remains after boiling them. The solution is the liquid that remained. Any solid residue on the bottom had been tranferred to another jar before adding the copper. So the solution only contained the filtered liquid plus some water from washing -no PCBs or else. 
I expected 10% silver in that solution but now I came to think that, this silver is the white sediment I have collected and filtered out before all that.

I would not expect iron, since it would be very unusual to find it there and in addition how could copper precipitate iron? There is only silver gold and the PGMs above copper, that is why I chose it. Even with zinc almost anything - but iron - would come down. But with copper one would expect that there is no BM since copper itself is a PM.

PdCl is a heavy colorizer. A few atoms seem to be enough to determine the color of the solution. Pd test was faint positive before adding the copper, but in fact that does not mean much, as I experienced.

So my next step could be: Dissolving in copper AP to digest the copper in that sample and then see what remains as black residue. You know I dont use nitric, so any better suggestion? I post the result afterwards.


----------



## butcher (Oct 8, 2012)

Thanks Marcel, 
That clears up my confussion here,
Things are not always what they look like.
A picture can be worth many words, but words can also be better than pictures sometimes.
My problem is I can easily get confused by words and pictures.


----------

