RareEarth - 28-7-2015 at 15:24
I have a palladium coin that I want to make into PdCl2. I did a bit of reading on the subject, and I understand the purpose of Aqua Regia for
dissolving these precious metals, but I am not sure of the chemistry going on.
The write up for PdCl2's that I've seen involved dissolving the Palladium metal, in HCl/Nitric Acid (Aqua Regia). After it has been dissolved, boil it
to dryness, add HCl, and then repeat 3 times.
From what I gathered the purpose of this is to get rid of the other various forms of Pd-Chlorine combinations that aren't PdCl2, and to concentrate
the PdCl2. This is where I am confused on. What by products are being gotten rid of? What's being boiled off? I want to understand what's going on
here so I'm not just following some recipe online trusting that it's optimized.
[Edited on 28-7-2015 by RareEarth]
bobm4360 - 28-7-2015 at 21:03
The purpose of the multiple boilings is to eliminate the nitric acid. An excellent reference is "Refining Precious Metals", by C. M. Hoke, available
(free) at goldrefiningforum.com. You may have to search a bit for it but it's there in at least 2 versions. There is also good information at http://www.orgsyn.org/demo.aspx?prep=CV3P0685.