# will this work



## pip (Nov 10, 2010)

I have a old aqua regia solution of pt, pd, rh, along with copper zinc iron and sodium. The solution has had urea added to bring up the ph. If I boil the solution down can turn it all into a sponge and clean the pgm's up with hcl? I'm not worried about seperating the individual pgm's yet just removing all non pgm's.


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## 4metals (Nov 10, 2010)

Why not just cement the values with copper. Then you can do a digestion to clean up the mixture you will drop but the base metals will remain with the first solution.


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## pip (Nov 10, 2010)

there is already copper in there, some did drop to the bottom but there is the ammonium compounds in there still I think will that be a problem? . Can I add zinc to do the same thing? I have that on hand.


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## Anonymous (Nov 10, 2010)

4metals said:


> Why not just cement the values with copper.





pip said:


> The solution has had urea added to bring up the ph.


It would depend on how high you raised the ph.If you raised it too much,you would first need to evaporate a percentage of the solution,then add fresh Hcl first before you could saturate it with copper.


pip said:


> there is already copper in there, some did drop to the bottom


if "copper" dropped then you have no more PM's or PGM's in solution.You need to verify if "copper" dropped as you said.


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## pip (Nov 10, 2010)

I didn't mean the copper dropped I meant that there is copper in there and some pgm's dropped but not all, maybe.


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## Lou (Nov 10, 2010)

Use copper to cement out the values, then filter and digest in aqua regia. The rest you need to know is here on the forum.


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## pip (Nov 11, 2010)

thank-you this site is pretty cool and defiantly helpful.


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## pip (Dec 22, 2010)

So I cemented the values, then added some more hcl to make sure there wasn't any metallic copper left. After the solids settled I decanted the solution away and was left with 33.4 grams of a red precipitate that developed a olive green layer on top after drying. 


This material came from 5 or 6 catylatic converters and I know its guesswork but would it be safe to assume its around 70 percent palladium 25 percent platinum and 5 percent rhodium? I'm just trying to figure out how much of each chemical used to cement the individual pgms I should be using.


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## lazersteve (Dec 22, 2010)

pip said:


> So I cemented the values, then added some more hcl to make sure there wasn't any metallic copper left. After the solids settled I decanted the solution away and was left with 33.4 grams of a red precipitate that developed a olive green layer on top after drying.



The color of your precipitate and it's reaction to air is indicative of copper. HCl by its self won't dissolve solid copper to any measurable degree, without an oxidizer present.

Mixed PGMs are black when precipitated via the cementation reaction, not red. Clean up the copper with diluted (35%) nitric acid.

Steve


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## Platdigger (Dec 22, 2010)

Steve wrote: " Clean up the copper with diluted (35%) nitric acid"

Not trying to be smart here but, may I add, after incinerating.
If there are residual chlorides after the HCL rinse....well...


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## pip (Dec 22, 2010)

platdigger are you saying I should roast the material first to remove the chlorides?


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## Platdigger (Dec 22, 2010)

Yes, but here is the thing, the nitric is also going to put your palladium into solution.
Just so you are aware that you will want to recover your palladium from your nitric before tossing it.


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## pip (Dec 22, 2010)

so first roast material to decompose chlorides, digest in nitric, filter platinum, boil off the nitric acid, rehydrade with hcl and evatorate 3 times to drive off resedual nitric acid drop with ammomium chloride. dissolve in ammonium hydroxide 10%, drop crud with more ammonium hydroxide, filter, add hcl to drop palladium. 

let me know if i'm missing/adding steps but I think "I got it".


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## lazersteve (Dec 22, 2010)

The nitric will dissolve your Pd as Platdigger suggested, so no need to perform the Palladium process unless your DMG is positive after the Pt is removed.

Don't boil when removing the nitric, low-medium heat to evaporate.

The clean up with ammonium hydroxide is for Pd also, not Pt.

Steve


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