Kevin,
The suggestion of dissolving all of the ammine complexes in AR was to save you the step of cementation and introduction of more impurities. A little zinc is probably helpful on the Pd refining side.
When digested in aqua regia, ammonium hexachloroplatinate (palladate, other ammine compounds), the amine ligand or ammonium cation is oxidized away.
Basically, one can reflux in aqua regia any hexachlorometallate, or ammine chloride, and get the respective metal acid. You are oxidizing away the nitrogen.
So, (NH4)2PtCl6 + excess NOCl + H(+) ---> H2PtCl6 + NOX/N2 gases; similarly for Pd.
You can digest Pd(NH3)2Cl2 in aqua regia and get [PdCl4](2-)
It is done when gas evolution stops and no more yellow salt remains to be seen.
Anyhow, your next step is to either to separate the Pd by the chlorate method, or to run a hydrolysis.
The suggestion of dissolving all of the ammine complexes in AR was to save you the step of cementation and introduction of more impurities. A little zinc is probably helpful on the Pd refining side.
When digested in aqua regia, ammonium hexachloroplatinate (palladate, other ammine compounds), the amine ligand or ammonium cation is oxidized away.
Basically, one can reflux in aqua regia any hexachlorometallate, or ammine chloride, and get the respective metal acid. You are oxidizing away the nitrogen.
So, (NH4)2PtCl6 + excess NOCl + H(+) ---> H2PtCl6 + NOX/N2 gases; similarly for Pd.
You can digest Pd(NH3)2Cl2 in aqua regia and get [PdCl4](2-)
It is done when gas evolution stops and no more yellow salt remains to be seen.
Anyhow, your next step is to either to separate the Pd by the chlorate method, or to run a hydrolysis.