Cementing palladium with copper

[100tific]

Hi everyone,
I would ask you something.
i had an alloy with gold a lot of silver and palladium and other bse metals, and i wanted to recover the gold. So first, i treat it with nitric acid to disolve palladium, silver and base metals.
Next i filtered it and i treated the solid with AR to refine the gold.
As the quantity of silver and palladium was so high, i wanted to recover them too, so i used NaCl to throw down the silver, and then i filtered it.
I found that the silver chloride was a little pink, and i looked the solid by XRF. I found that this solid had Pd, Au and Ag.
Then, i used diluted hydrochloric acid and let it 24h, then i filter the solution. When i saw the solid, it didn't have Pd, only had silver and gold. So i let itfor melt it later.
As the resultant liquid, which has Pd , now don't have silver and gold, i tried to recover it with Cu.
I can see how Pd particles put on it, but the reaction is veeeery slow. I am stirring the solution with the copper inside. But i want to know how slow is this process, and what can i do to speed up it.
Could you help me please?

 

[Yggdrasil]

Hi everyone,
I would ask you something.
i had an alloy with gold a lot of silver and palladium and other bse metals, and i wanted to recover the gold. So first, i treat it with nitric acid to disolve palladium, silver and base metals.
Next i filtered it and i treated the solid with AR to refine the gold.
As the quantity of silver and palladium was so high, i wanted to recover them too, so i used NaCl to throw down the silver, and then i filtered it.
I found that the silver chloride was a little pink, and i looked the solid by XRF. I found that this solid had Pd, Au and Ag.
Then, i used diluted hydrochloric acid and let it 24h, then i filter the solution. When i saw the solid, it didn't have Pd, only had silver and gold. So i let itfor melt it later.
As the resultant liquid, which has Pd , now don't have silver and gold, i tried to recover it with Cu.
I can see how Pd particles put on it, but the reaction is veeeery slow. I am stirring the solution with the copper inside. But i want to know how slow is this process, and what can i do to speed up it.
Could you help me please?

When cementing PGMs you need to have aggressive stirring that dislodge the particles as they cement.
If not it will "plate" the Copper and effectively stop the reaction.
This can be done by air bubbling, stir bar or similar.
But the stirring need to be established before the Copper is inserted.

 

[kurtak]

I can see how Pd particles put on it, but the reaction is veeeery slow. I am stirring the solution with the copper inside. But i want to know how slow is this process, and what can i do to speed up it.

Read ALL of this thread ------

https://goldrefiningforum.com/threads/fuzz-button-interconnects-need-some-advice.22203/#p232030

Kurt

 

[100tific]

thanks is my first time cementing with copper

 

[FrugalRefiner]

See When In Doubt, Cement It Out.

Dave

 

[nickvc]

You will probably find that the gold will cement out first but the palladium can take some time even with constant agitation.
With high silver low other values you may well be better off simply melting and putting the resultant bar into a silver cell and concentrate the values in the slimes while taking fine silver off the cathode.

 

[100tific]

Finally i think i will buy DMG.
Thank you very much.

 

[Alondro]

If you know the solution has only Pd in it, wouldn't cementing on ZINC be a far better idea? If it's palladium CHLORIDE acidic pH solution, then aluminum would be even better, since aluminum chloride is INCREDIBLY soluble in acid chloride solutions and plating won't be an issue since the Al will be dissolving so fast the solution will be working beneath the Pd as quickly as it cements.

If it's got nitrate in it, then use zinc, because aluminum in acidic nitrate solution forms a layer of impermeable aluminum nitride on the metal surface.

Really, if you know you only have PMs in the solution, then dropping them with the most reactive metal (that won't automatically ignite or explode, such as alkali metals!) is better for complete and rapid cementation.

The only reason to use copper is if you still have base metals in the solution that you DON'T want to reduce back to metal. But it sounds like from your description that you've already removed most, if not all of the base metal.

 

[Yggdrasil]

If you know the solution has only Pd in it, wouldn't cementing on ZINC be a far better idea? If it's palladium CHLORIDE acidic pH solution, then aluminum would be even better, since aluminum chloride is INCREDIBLY soluble in acid chloride solutions and plating won't be an issue since the Al will be dissolving so fast the solution will be working beneath the Pd as quickly as it cements.

If it's got nitrate in it, then use zinc, because aluminum in acidic nitrate solution forms a layer of impermeable aluminum nitride on the metal surface.

Really, if you know you only have PMs in the solution, then dropping them with the most reactive metal (that won't automatically ignite or explode, such as alkali metals!) is better for complete and rapid cementation.

The only reason to use copper is if you still have base metals in the solution that you DON'T want to reduce back to metal. But it sounds like from your description that you've already removed most, if not all of the base metal.

Aluminum has some bad habits.
It forms a hard to filter gel it you forget it in the vessel.
Don't ask how I know

 

[Alondro]

Aluminum has some bad habits.
It forms a hard to filter gel it you forget it in the veksel.
Don't ask how I know

Yeah, if your solution is concentrated, the Al salts will form a solid gel if left sitting for a while. I used to make it deliberately because it was neat to toy with. But I'm assuming the OP would like to get the Pd out pretty quickly! A relatively dilute solution of AlCl3 will remain liquid for a LONG time.

 

[Swissgoldrefiner]

Finally i think i will buy DMG.
Thank you very much.

What i hate with DMG is that it's not easy to get back to Pd metal...except it you burn it, but then you have some loss...

 

[Yggdrasil]

What i hate with DMG is that it's not easy to get back to Pd metal...except it you burn it, but then you have some loss...

You can redissolve it and use Formate reduction.

 

[Swissgoldrefiner]

You can redissolve it and use Formate reduction.

yes, good luck...it takes houers, not everything dissolve. easy to over shoot the reraction...even kadrive over shoot it...check his video

 

[Yggdrasil]

yes, good luck...it takes houers, not everything dissolve. easy to over shoot the reraction...even kadrive over shoot it...check his video

Read Hokes book.
It should be both quick and complete.

 

[Alondro]

Read Hokes book.
It should be both quick and complete.

Sreetips showed a very interesting method of reducing Pd with chlorine gas, ammonium chloride, and ammonia. It looks MUCH simpler than any other method I've seen, and worked quickly.

 

[Yggdrasil]

Sreetips showed a very interesting method of reducing Pd with chlorine gas, ammonium chloride, and ammonia. It looks MUCH simpler than any other method I've seen, and worked quickly.

This do not reduce it metal do it?
You will precipitate a salt and then you have to calcine it.

 

[Alondro]

This do not reduce it metal do it?
You will precipitate a salt and then you have to calcine it.

yes. The video is here:

But the resulting salt calcines and decomposes into pure palladium sponge at a fairly low temperature, not more than a few hundred degrees. That's certainly a lot simpler than the other methods.

The one thing I wonder is if one has palladium NITRATE in solution, must it first be converted to another type of solid palladium salt, filtered out of the nitrate solution, and then redissolve in ammonia for this to work. I don't know if bubbling chlorine gas through palladium nitrate solution will drop the initial red palladium salt.

 

[Yggdrasil]

yes. The video is here:

But the resulting salt calcines and decomposes into pure palladium sponge at a fairly low temperature, not more than a few hundred degrees. That's certainly a lot simpler than the other methods.

The one thing I wonder is if one has palladium NITRATE in solution, must it first be converted to another type of solid palladium salt, filtered out of the nitrate solution, and then redissolve in ammonia for this to work. I don't know if bubbling chlorine gas through palladium nitrate solution will drop the initial red palladium salt.

The Chlorine is to make sure the Pd salt has the correct valence.
You can use Sodium Chlorate in stead.
Then drop with either KCl or NH₄Cl not Ammonia
And it should work well in Palladium Nitrate
The resulting salt can be calcined but if you are not careful you will have losses.

Have you read Hokes version on reduction with Formic acid?
It is very complete and fast, no risk of losses.

 

[100tific]

If you know the solution has only Pd in it, wouldn't cementing on ZINC be a far better idea? If it's palladium CHLORIDE acidic pH solution, then aluminum would be even better, since aluminum chloride is INCREDIBLY soluble in acid chloride solutions and plating won't be an issue since the Al will be dissolving so fast the solution will be working beneath the Pd as quickly as it cements.

If it's got nitrate in it, then use zinc, because aluminum in acidic nitrate solution forms a layer of impermeable aluminum nitride on the metal surface.

Really, if you know you only have PMs in the solution, then dropping them with the most reactive metal (that won't automatically ignite or explode, such as alkali metals!) is better for complete and rapid cementation.

The only reason to use copper is if you still have base metals in the solution that you DON'T want to reduce back to metal. But it sounds like from your description that you've already removed most, if not all of the base metal.

there are base metals too, it is for that i used Cu.

 

[Wonka]

I have read of a different way to drop platinum. I’m in the middle of the process so I’m not sure of its effectiveness., but use ammonium chloride to saturate the solution then add hcl slowly while heating at 80-100C. This causes the platinum salts to break down to pure platinum metal. Then dump the metal in AR to get rid of any impurities. It looks like it’s working so far but I’ll have to wait tell it’s tested for the results.