Sciencemadness Discussion Board

Is it silver? -> Cutlery plating

Daffodile - 22-3-2016 at 19:30

Alright so I was going through those Extractions&Ire videos, and I decided to make some Dichromate.

Luckily, I had all this old cutlery and shit, mostly spoons, whatever that's worth. So, I put them in an old yogurt container, and added some Hydrochloric acid (34.45%).

After a few days, I noticed this wierd thing. Instead of corroding how I expected, the partially dissolved cutlery had this undissolved metal layer on the outside, a flaky coat that was obviously once the outer surface of the spoons. Its sorta like hollow pennies once you dissolve the zinc insides.

So this is odd, or at least to me. The crumbly layer is a shiny bright metal, but I don't know what to expect since the cutlery was really cheap shit. Usually I'd say its silver, but the total mass of the metal on each spoon would have made the cutlery more expensive.

I might throw some Nitric acid at the stuff once I get back home, but right now I'm just pitching this to see if anyone has any ideas.



[Edited on 23-3-2016 by Daffodile]

Sulaiman - 22-3-2016 at 23:11

my first guess wold be EPNS, electroplated nickel silver https://en.wikipedia.org/wiki/Nickel_silver
(copper:nickel:zinc = 60:20:20, with Ag plated surface)
extremely popular here in UK before stainless steel cutlery became widely available.
At the moment silver costs US$0.5 per gram, not as expensive as you may think.

If you throw some Nitric acid at the stuff once you get back home,
you will have difficulty separating the copper and silver,
and it would not be worth the effort and reagents.

Daffodile - 23-3-2016 at 08:14

Quote: Originally posted by Sulaiman  
my first guess wold be EPNS, electroplated nickel silver https://en.wikipedia.org/wiki/Nickel_silver
(copper:nickel:zinc = 60:20:20, with Ag plated surface)
extremely popular here in UK before stainless steel cutlery became widely available.
At the moment silver costs US$0.5 per gram, not as expensive as you may think.

If you throw some Nitric acid at the stuff once you get back home,
you will have difficulty separating the copper and silver,
and it would not be worth the effort and reagents.


Thanks dude. I really wasn't interested in recovering anything, I just wanted to know what it was.

PHILOU Zrealone - 25-3-2016 at 06:42

Quote: Originally posted by Sulaiman  

If you throw some Nitric acid at the stuff once you get back home,
you will have difficulty separating the copper and silver,
and it would not be worth the effort and reagents.

Untrue!

The only reagent needed for separation would be native copper (metallic or Cu(0))...see cementation process...only more oxydant cation than copper will be reduced and precipitate metallic powder --> noble metals.

2 Ag(+) + Cu(0) --> 2Ag(0) + Cu(2+)
Cu(2+) + Cu(0) -/->

Sulaiman - 25-3-2016 at 07:05

Ah yes, I forgot ... well corrected.

that would be a nice process to examine.
I would neutralise any excess nitric first with urea etc.
or a lot of copper will become copper nitrate.