Random - 20-5-2013 at 13:19
Took a copper wire I found on the street, it had darker color than usual orange copper. More like dark brown-orange. Even when I cut it fresh it was
darker than usual.
Dissolved it in HCl + NH4NO3 small addition for faster reaction. Added NaHCO3, precipitated. That was done 2 years ago.
Now there on the bottom of the jar, settled a small amount of dark gray powder, under the copper carbonate. Tried to add it to vinegar, CuCO3
dissolved very fast, but that powder didn't. It took one day approximatelly to dissolve it.
What could it be? Arsenic? Lead? Metal or compound?
Pyro - 20-5-2013 at 14:05
most likely lead. it is commonly added to copper wires.
ElectroWin - 20-5-2013 at 14:25
here is a list of common alloys of copper
http://www.radcliffwire.com/alloy_copper.htm
Random - 21-5-2013 at 12:57
It might be lead then, does that mean it didn't dissolve in HCl at all? Because it can't be that I precipitated it with NaHCO3, maybe some gray IV?
oxide yeah though, given the oxidizing conditions of poor man aqua regia.
What would be the best way to get rid of it?
[Edited on 21-5-2013 by Random]