recovering pd from nitric containing copper?

[Oz]

Goldenchild,
I agree with samuel-a that cementing both on copper then trying to remove the Pd with HCl is the wrong way to go.

If you have Ag and Pd digested in nitric I would typically suggest removing the silver as a chloride then cementing the Pd on copper. I say typically, only because if you are only talking small traces of Pd it may be more cost effective to remove the Pd with DMG, then cement the silver on copper in order to avoid the hassle of silver chloride.

I hope this time my answer made sense.

 

[Oz]

Samuel,
Thanks for testing that with a known quantity of Pd at a boil. Like I said, I was rather sure but had not tried heat.

 

[samuel-a]

well... actually i should thank you for provoking me to further pursue this subject.

To further prove your claim, i took some snap shots :
left - Pd Nitrate saturated with Ag. Center+Right - HCL addition and AgCl precipitation.

 

[Oz]

Nice to see you testing. You will need to wash your silver chloride several times in order to remove the bulk of the Pd nitrate that is trapped in it. Silver chloride is terribly good at drag down contamination.

 

[samuel-a]

Silver chloride is terribly good at drag down contamination.

Yup...

 

[goldenchild]

This is exactly how I pictured this technique playing out. I dont mind dealing with AgCl so thats why I suggested it. I think vaccum filtration would be best in this case. Not #5 or even #2 paper though!

 

[kjavanb123]

Hi

Followed the advise in this thread and for the first time I tried to precipitate palladium from a copper nitrate solution.

I had a nitrate solution mostly copper and trace of palladium, so I dropped a 204 gram copper ingot into the solution after 24 hrs, there are some black fines stuck to the copper ingot as can be seen below,

Copper before cementation,


Copper after 24 hrs into nitrate solution with mostly copper with small amount of Pd.


Now the question is how one removes the black powder which seems to be stuck to copper ingot.

Best regards
KJ

 

[4metals]

In low concentrations and nitric based solutions have you considered DMG?

 

[kjavanb123]

4metals,

I have already know about the DMG usage, a I have used that to precipitate Pd from nitrante solution.

This is my first trial with plating on copper, hence this experiment.

I forgot to weigh the copper ingot before putting it in the nitrate solution, so by weighing it now I can estimate the Pd amount.

Best regards
KJ

 

[FrugalRefiner]

I forgot to weigh the copper ingot before putting it in the nitrate solution, so by weighing it now I can estimate the Pd amount.

That wouldn't have helped. In cementation, copper dissolves into the solution to replace the palladium (and any other metals below copper in the reactivity series), so the copper would lose weight in the reaction. You also wouldn't know how much copper was simply dissolved by any excess nitric.

Dave

 

[nickvc]

Kevin when using copper to cement PGMs it helps to have agitation, a bubbler will do, and to use a large surface area of copper high cements the PGMs more fully and quicker, to recover the palladium or any other PGM I’d use a cell to concentrate the values which makes recovery easier.

 

[kurtak]

Kevin when using copper to cement PGMs it helps to have agitation, a bubbler will do, and to use a large surface area of copper high cements the PGMs more fully and quicker, to recover the palladium or any other PGM I’d use a cell to concentrate the values which makes recovery easier.

Correct - using a bubbler will also "help" to prevent the PGMs from adhering to the copper which can in turn cause a "passivation" layer of PGMs on the copper which in turn can prevent the PGMs from completely cementing out of the solution

Kurt