rhodium plated over copper wire

[goldsilverpro]

Arthur,

Were those plating wires used only once or were they used for multiple cycles? If multiple cycles, there could be alternating layers of nickel between the Rh layers. You said you got higher yields with nitric than with AR. Maybe all the Ni wasn't leached out with the nitric, whereas it was with AR. If it wasn't real hot, that could happen. Test the Rh foils from the nitric with a good magnet to see if any Ni is present.

If they are gold plating also, there could be some gold layers there that aren't touched with nitric but are dissolved with AR. In this case, though, you would probably see the gold color.

If some Rh is dissolving with AR, maybe you can prevent this by diluting the AR a bit with water - say, 25% water. Even dilute, it should still quickly dissolve the Cu and Ni. Play with some samples.

 

[arthur kierski]

thanks Oz for rememorize to me that rh foils will not dissolve in ar----i work with rh for sometime and also boiled rh powder in ar for hours to put in solution any impurities(in this case base metals and au,pt ,pd)and no rh was dissolved--------------
just to mention:i make a ar solution (4hcl to 1hno3+2litres of water) and dissolve rapidly 1kilo of the wire in a plastic bucket---no heat is needed-------
as i do not have the expertize yet to do the ap method that palladium mentioned,i will get the rh foils with ar------
thanks all for reading this thread and the wonderful sugestions that was passed to me
Arthur

 

[arthur kierski]

Gsp,the plated wires are only plated with rh--sometimes the wire is used many times,but just for rh plating
the fantasy jewellery that i did last year with ar ,certainly had ni under the rh plating and certainly some rh went to solution(when rh is in form of alloy it dissolves in ar)---thanks for the questioning -----
next week i will receive some fantasy jewllery (with defects) and for all you mentioned i will obtain the rh foils with nitric acid---
thanks once more for clearing my mind with my doubts
Arthur

 

[fenzers]

Hi

I'm new to the forum and do not understand some technical words used by you.
I have a small GALVANICA in Portugal and I use copper wire to hold the pieces are rhodium plated. My question has to do with being able to recover the rhodium that same copper wires. I usually sell the copper, but that only gives 5 € / kilo, and I think he earned more while recovering rhodium. The copper wire has no nickel, rhodium bath only.
Is it possible to explain to me all the steps to rhodium recovered not in copper wires?
Best Regards

Marcio

 

[goldsilverpro]

Welcome to the forum, Marcio.

You have only copper and rhodium. Simply dissolve the copper and you would be left with fairly pure rhodium. Since rhodium plating is highly stressed, it will most likely break up into small slivers. There are several ways of dissolving the copper. The most common would be nitric acid or a combination of HCl and hydrogen peroxide, both of which are covered in detail on this forum.

Chris