The data I compiled in the chart I posted above is from several very early chemical text that clearly states plain ammonium chloride will precipitate Pd from nitric solutions.
In Hoke she is assuming we have mixed PGM solutions, in these cases the solution is denoxxed to allow partial separation of the Pt and Pd. Since your solution is primarily Pd in nitric solution you shiould be fine with NH4Cl only. Make sure the Pd solution is very concentrated (blood red, burgundy wine color) before adding the saturated solution of ammonium chloride (37.2 g/100mL @20C). Remember that adding ammonium chloride to water will produce a cold solution (endothermic), so less than the above stated amount of NH4Cl will dissolve in the given volume of water. I typically make up a large bucket of saturated NH4Cl solution to keep in the lab with excess NH4Cl crystals in the bottom to assure saturation. Allow this mix to sit for sometime before using as the salt does not instantly dissolve, before use it should still have solid crystals in the bottom. Make sure you don't add any solids to the Pd solution when precipitating. It's fine to perform the ammonium chloride addition at room temperature or below.
You should try a small sample of the cold concentrated solutions (Pd nitrate and ammonium chloride) to be certain you will get precipitates when they are mixed. If your sample does not precipitate a brick red (or lighter towards yellow) salt as soons as you add the solutions together, one or both of the solutions is not concentrated enough.
If you Pd salt precipitates as a bright yellow color, it is very pure and does not need to be repurified. If it is darker colored towards brick red it needs purification.
Pure Pd Colored Powder:
Dirty Pd Colored Powder
If the color is darker than the first photo, repurify it.
Keep me posted on your progress.
In Hoke she is assuming we have mixed PGM solutions, in these cases the solution is denoxxed to allow partial separation of the Pt and Pd. Since your solution is primarily Pd in nitric solution you shiould be fine with NH4Cl only. Make sure the Pd solution is very concentrated (blood red, burgundy wine color) before adding the saturated solution of ammonium chloride (37.2 g/100mL @20C). Remember that adding ammonium chloride to water will produce a cold solution (endothermic), so less than the above stated amount of NH4Cl will dissolve in the given volume of water. I typically make up a large bucket of saturated NH4Cl solution to keep in the lab with excess NH4Cl crystals in the bottom to assure saturation. Allow this mix to sit for sometime before using as the salt does not instantly dissolve, before use it should still have solid crystals in the bottom. Make sure you don't add any solids to the Pd solution when precipitating. It's fine to perform the ammonium chloride addition at room temperature or below.
You should try a small sample of the cold concentrated solutions (Pd nitrate and ammonium chloride) to be certain you will get precipitates when they are mixed. If your sample does not precipitate a brick red (or lighter towards yellow) salt as soons as you add the solutions together, one or both of the solutions is not concentrated enough.
If you Pd salt precipitates as a bright yellow color, it is very pure and does not need to be repurified. If it is darker colored towards brick red it needs purification.
Pure Pd Colored Powder:
Dirty Pd Colored Powder
If the color is darker than the first photo, repurify it.
Keep me posted on your progress.