White Foil After Nitric Acid.

[Franciz]

Hi All,

Today i have dissolved 2Lbs of silver plated wire with copper base in 50/50 Nitric Acid in a bucket, After the copper and silver has gone<Reaction Stop> I left with full of silver color foil in the bucket.

I wash the foil and try dissolved in Nitric again but again no reaction, I filtered out the foils and put it in 400ml HCl and 100ml HNO3<AR> After 1min or so reaction start but after 1/2Hr the foils is still there so i try heated it about 1/2Hr and still full of foils.

I gave up and leave it to cool down, I saw some purple grey powder settle and foils on top.
I filtered and washed the foils and powder and smelted it, It came out a nice silver button with no other traces but not very bright.
I hammer it until it became flat and that is what it looks like in the picture :lol: :lol: :lol:

May i know what is this?

Francis

 

[nickvc]

Franciz the fact that it did not react at all with the nitric means it certainly is not silver, it also precludes many other metals. The small reaction in the AR could be the acids removing either more base metals or perhaps gold, the one possibility that leaps to mind is rhodium, is this material from a jewellery source?

 

[Franciz]

Franciz the fact that it did not react at all with the nitric means it certainly is not silver, it also precludes many other metals. The small reaction in the AR could be the acids removing either more base metals or perhaps gold, the one possibility that leaps to mind is rhodium, is this material from a jewellery source?

Yes Nickvc, You are right it is from a jewellery source. I also think that is rhodium but i am not sure as i have never dissolved Pt in AR before. How long will it takes to dissolve Pt foils in AR normally?

There is no gold in AR i have test it with stannous chloride.
The foils just reaction slowly with AR and Turns into powder and settle on the bottom.

Thanks
Francis

 

[lazersteve]

The white/silver foils are most likely Rhodium.

They will dissolve in hot concentrated sulfuric acid (very dangerous and toxic stuff) to a brown solution:

or you can fuse them in a sodium chloride + potassium bisulfate melt, followed by taking the resulting salt up in hot water.

Steve