# Cemented Palladium



## kernels (Sep 14, 2016)

Hi guys,

After a reasonable amount of experience with recovering and refining gold, I recently attempted to process some MLCCs just out of curiosity.

I think I did screw up a bit in that I went straight to nitric acid without first treating the crushed capacitors with Hydrochloric acid. I was intending for silver and Palladium to be dissolved, and then recover both through copper cementing. Somehow I believe I ended up with only Palladium in solution and Silver Chloride. Not sure how I ended up with Silver Chloride since I didn't have any HCl anywhere near the reaction vessel.

Anyway . . . I cemented the precious metals out of the solution with some copper and ended up with the powder pictured below. Can you guys with a bit more experience confirm whether it looks likely to Palladium.




Thanks!


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## kjavanb123 (Sep 14, 2016)

Hi,

From picture it seens like meta stanic acid. 

Regards
Kj


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## mls26cwru (Sep 14, 2016)

from everything that I have read, cemented palladium is usually jet black... I just refined a very small amount with DMG/zinc and the cemented sponge was very voluminous and black as could be. 

I dont have much experience with Pd though, so I will be keeping an eye on this thread.


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## kurtak (Sep 14, 2016)

As already mentioned Pd sponge is normally quite black

being as how you went right to nitric instead of pretreating with HCL - the white precipitate you saw after the nitric treatment was most likely stannic tin & not silver chloride (from solder)

As long as you ran your nitric treatment hot enough & long enough & with a bit more nitric then actually needed you should have dissolved both your silver & Pd --- & due to the silver - the cemented powders are going to have more of the color of silver cement then the color or cemented Pd 

The only way you are going to know for sure if you got both your silver & Pd is to re-dissolve your powders (or at least a small sample) & then test the solution with prepared DMG

Or if you don't have DMG - you can dissolve some of the powders - then precipitate the silver as silver chloride - then test the solution with stannous for Pd 

If your solution was not "completely" clear (a bit cloudy) when you cemented it - its probably because of stannic tin that didn't settle/filter in the original solution & then dragged down in the cementing - which in turn would result in the cement having a lighter color as well

after cementing - did you test a sample of the solution --- first with HCl to see if all the silver was out - then with DMG (or stannous if you don't have DMG) to see if all the Pd was out

Kurt


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## Lou (Sep 14, 2016)

I attached a photo of Pd sponge.

Looks like it to me. It's not necessarily black!


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## g_axelsson (Sep 14, 2016)

Lou said:


> I attached a photo of Pd sponge.
> 
> Looks like it to me. It's not necessarily black!


Is that cemented or from some other process?

Göran


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## Lou (Sep 15, 2016)

Formate.


But if it is pure it should dry to a grey powder...


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## kernels (Sep 15, 2016)

Hi guys, sorry about taking so long to come back, busy couple of days with the day-job! 

Thanks to everyone for the helpful and detailed replies. After reading through them I believe that what I thought was silver-chloride was actually meta stanic acid, and what I cemented out (with copper from a clear solution) is actually going to be a mixture of mostly silver with a little bit of palladium. I will re-dissolve and test as per Kurt's guidance.

And next time, I will do more reading and less experimenting ! 
Thanks!


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## anachronism (Sep 15, 2016)

Lou

Brilliant picture what are those lamps please and where can I buy some?


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## nickvc (Sep 15, 2016)

They look like heat lamps to me which are used to dry the powders, you can do the same with a Pyrex dish and a cheap plug in oven


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## Lou (Sep 15, 2016)

Restaurant supply. Suggested to get the stainless pans there, engrave the tare weight on them and use them.

We fill those up with gold, silver shot, and with Pd/Rh/Pt sponge.


If one makes the Pd sand per freechemist, it needs no calcination as it has a low enough surface area.

The formate sponge still needs to go through a vacuum bake out at 400 C to remove O/CO/CO2.

Lou


@Kernels...
if you had no silver in solution and used copper, it should be quite clean Pd.

In the future...do the nitric treatment, separate the solids and then precipitate the silver as its chloride. Then you can cement the Pd with copper and be good to go!


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## anachronism (Sep 15, 2016)

Lou thanks appreciate it. Online shopping as we speak.


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## kernels (Sep 16, 2016)

Lou said:


> @Kernels...
> if you had no silver in solution and used copper, it should be quite clean Pd.
> 
> In the future...do the nitric treatment, separate the solids and then precipitate the silver as its chloride. Then you can cement the Pd with copper and be good to go!



Thanks Lou, great, straight-forward advice there. Will do just that.


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## nickvc (Sep 16, 2016)

Lou advice as usual is spot on but can I add that the solution you have or will have is very toxic so stay safe and wear gloves and work under a fume hood..


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## kernels (Sep 17, 2016)

nickvc said:


> Lou advice as usual is spot on but can I add that the solution you have or will have is very toxic so stay safe and wear gloves and work under a fume hood..



Thanks nickvc, I always do (gloves, glasses and fume hood) I have no desire to slowly (or quickly) poison myself for what is really just a hobby.


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## Lino1406 (Nov 4, 2016)

I prefer to de-nox the Pd solution with sulphamic acid and cement it with Zn. So few water rinses and HCl get rid of the left Zn


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