# how to drop Pd from nitric Acid ?



## amitoha23 (Apr 3, 2013)

Hi,

after extracting silver from silver Palladium solution , i was left with reddish liquid containing salt + Pd.

can i use Aluminum Foil to drop Pd , and then refine it using HCl (as i tried drying it , salt was building up in the bottom preventing me from getting rid of Nitric Ions )

Any advice will be welcome 

Regards
Amit


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## Geo (Apr 3, 2013)

you cant wash Pd powder with hcl as it will just put it back into solution. if its just Pd in solution, you can use zinc.aluminum will contaminate the powder.some members use copper to cement the Pd out of dirty solutions and then refine the powder.what you are asking about is a recovery process and not a refining process.refining Pd has been discussed very thoroughly on the forum.


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## etack (Apr 3, 2013)

Great read. http://goldrefiningforum.com/phpBB3/viewtopic.php?f=48&t=9477&p=90800&hilit=freechemist+DMG#p90800

Eric


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## amitoha23 (Apr 6, 2013)

Geo said:


> you cant wash Pd powder with hcl as it will just put it back into solution. if its just Pd in solution, you can use zinc.aluminum will contaminate the powder.some members use copper to cement the Pd out of dirty solutions and then refine the powder.what you are asking about is a recovery process and not a refining process.refining Pd has been discussed very thoroughly on the forum.



I Have try dropping the Pd using aluminum . it seem to drop all metal as expected . i have refined it again using cold Hcl . after a few hours i dried the powder and melt . 
did the Hcl wash is enough to get all aluminum out and will i be left with Pd ? (if i am sure no outer metal was there before ) 

how do you suggest refine the Aluminum Pd powder ?

Regards
Amit


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## Geo (Apr 6, 2013)

try here. http://goldnscrap.com/index.php?option=com_content&view=category&layout=blog&id=40&Itemid=52


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## Marcel (Apr 7, 2013)

I found (and still find) Pd tricky when it comes to precipitation. Pd is a very "unnoble" metal, which will disolve in many acids very easily. Which is fine for recovering but can be a problem with dropping it from the solution completly. Nictric acid is very strong and will not give up the Pd so easy. Denox the solution, try to replace the Pd nitrates with Pd chlorides, by adding HCL, use some temperature to enhance the process or give it some time (a few days rather than hours or minutes).
I still prefer to use copper as precipitant. It is very easy to controll when the dropping process has ended. Pd covers the copper with a black layer when precipitating. It will fall off or can be knocked down. Once there is no more Pd left in solution, only copper will dissolve and there will be no black layer on the copper from that point on. The copper will just take its original color. The solution may turn greenish from orange/red/burgundy which is also a sign that the copper has replaced the Pd that was in the solution.


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## amitoha23 (Apr 15, 2013)

Thank you for your answers , 
i have order 4pounds of Zinc powder . as it seems easier to just use that to drop the Pd. when i use the zinc i can just melt the powder left or i need to remove any zinc leftovers ?

Regards
Amit


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## etack (Apr 15, 2013)

If you are dropping Pd from a nitric solution then use weak sulfuric around 10%. This is so you won't put your Pd back into solution, and you will rid it of any extra Zinc.

When Pd is in solution use freechemist way it works great just keep it acidic or you will get the nickel to precipitate if you have any from your feedstock.

Eric


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## amitoha23 (Apr 16, 2013)

etack said:


> If you are dropping Pd from a nitric solution then use weak sulfuric around 10%. This is so you won't put your Pd back into solution, and you will rid it of any extra Zinc.
> 
> When Pd is in solution use freechemist way it works great just keep it acidic or you will get the nickel to precipitate if you have any from your feedstock.
> 
> Eric



Thank you , how should i know if i put enough Sulfuric in the solution ? then i should filter it and melt ? 

Regards
Amit


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## etack (Apr 16, 2013)

Just wash with enough that it stops fizzing. Zinc will react quite fast with Sulfuric and so will Al.

Eric


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## Lou (Apr 16, 2013)

Potassium thiocyanate will drop palladium (and silver).

The resulting salt can then be cemented with zinc.


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## amitoha23 (Apr 17, 2013)

tried some Al Powder with the Pd Liquid . i have some problems filtering this black Pd,Al powder . it seem to clog all of my filter Paper very fast . how do you suggest to filter it ?
it seem that the liquid is clear in color with foggy black cloud inside and some powder on the bottom . i tried filtering it wit 102 medium Filter paper and vacuum system . 
and i have tried Coffee filter . both seem to clog fast , 

some liquid i did managed to filter was water clear , Tested with DMG : result Pd negative 

Regards
Amit


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## lazersteve (Apr 17, 2013)

I use aluminum foil. If you have access to some high purity Al foil this would be best, but the household stuff will work in a pinch. Tear the foil into small strips and add them one at a time until each completely dissolves, then add another if the solution is still positive. 

The Pd will form in larger sponge like clusters if your aluminum is in foil form. Fine grain Al powders will form very finely divided Pd black. High purity Al turnings would be a great choice for this reaction as well. Avoid using aluminum alloys so you are not adding additional contaminates to your Pd.

Steve


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