Chromic etch

[lawsonland]

Hi,
I have some pieces of gold ribbon, it is already 99.99%. If I just wash it in chromic etch (its nitric acid and Ceric ammonium nitrate) will that be sufficient to remove any other contaminant metals?

Also if I use AP to get gold foils/traces off a PCB and then use the chromic etch would I still have to disolve the gold in HCl/Cl. Wouldn't this make it pure enough.

What other uses is Chromic etch good for? Why is there Ceric Ammonium nitrate in it?

Any bad points about it, what happens if it gets mixed with the AP?
Thanks

 

[goldsilverpro]

As I understand it, this etch is used to etch chromium masks in the thin film industry. It is also used to clean glassware. It will also attack Cu and Ag. It may only slightly attack nickel. If the ribbon is 99.99% pure to start with, just about anything will clean it. There can't be any oxides. If anything, all there probably is is soil or grease.

Most of the gold plating, itself, on a PCB is only 99% to 99.9% pure. Metal additives (Ni, Co, etc.) are added to the gold to make it harder. Therefore, even if you could dissolve everything except the gold plating, the gold would not be pure enough to sell as pure gold - you need at least 99.95% purity.

I think the ceric ammonium nitrate is the oxidizer.

I know of nothing in this business that the chromic etch is good for. To me, it would be a waste to use it unless there were a good reason. Also, hexavalent chromium waste is considered very hazardous by the powers that be.

BTW, I deleted your other post, since it was a duplicate of this one. A rule of the forum is NO duplicate posts!