# Pd nitrate and SMB issue



## kjavanb123 (May 28, 2011)

All,

I know this has been posted before, but I can't find a clear instruction of what to do with it. I have Pd nitrate concentrated, and I simply want to know in order to precipitate the Pd from that solution using SMB, what is the next step? freechemists mention using lye to rise the pH then use SMB? should i warm it up? 

Thanks
Kev


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## Harold_V (May 28, 2011)

Might be a good idea for you to review Hoke in regards to extracting palladium. It is generally accomplished by using ammonium chloride and sodium chlorate. The use of SMB isn't one of the preferred options, which may be why you are having difficulty finding instructions in its use. 

When ever you have questions about processing, you most likely can find a satisfactory answer in Hoke's book. 

Harold


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## jimdoc (May 28, 2011)

Harold_V said:


> When ever you have questions about processing, you most likely can find a satisfactory answer in Hoke's book.
> Harold



If Hoke's doesn't give you answers, Steve's videos and tutorials will probably give you the answer for the newer methods. Its all here somewhere on this forum.

Jim


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## samuel-a (May 28, 2011)

Pd precipitated from nitrate solution using SMB can prove difficult to wash properly, much similar to AgCl.

If you already have concentrated Pd nitrate solution, i can't see any reason why you should use SMB insted of NH4Cl+Cl2.
One exception i can think of, is if silver is also in solution, maybe then it will be a good idea to use SMB and then cementing Ag with copper. Anyhow, both metals will need further refining.

I don't know how pH adjustment will effect the process, if at all, but it seems that also with SMB, a complete precipitation is not obtained (traces remains in stu) and the rest should be cemented (either by Cu or other more reactive metas).

Heat might help solids settle faster, but on the other hand will drive off SO2 gas from the solution.


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## lazersteve (May 29, 2011)

kjavanb123 said:


> All,
> 
> I know this has been posted before, but I can't find a clear instruction of what to do with it. I have Pd nitrate concentrated, and I simply want to know in order to precipitate the Pd from that solution using SMB, what is the next step? freechemists mention using lye to rise the pH then use SMB? should i warm it up?
> 
> ...


Add HCl and evaporate, repeat three times to denox, adding HCl between each evaporation.

From this point you can use NH4Cl & sodium chlorate.

Steve


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## kjavanb123 (May 30, 2011)

All,

Thanks for your input. I finally got it. I added zinc to the Pd nitrate solution, brown fumes came out, after some addition it won't longer dissolve zinc, so i added HCL and keep doing it till i got black powder. I will try Steve method.




After removing Pd from the original mixed black powder, I dissolved the residue in hot concentrated sulfuric acid and let it boil for few mins, dilute it, and test with stannous and got this result. Rh?





Thanks
Kev


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## freechemist (May 31, 2011)

Hello Kev,

In your post you mention an earlyer reply of me on one of your questions:

_"I know this has been posted before, but I can't find a clear instruction of what to do with it. I have Pd nitrate concentrated, and I simply want to know in order to precipitate the Pd from that solution using SMB, what is the next step? freechemists mention using lye to rise the pH then use SMB? should i warm it up?"_ 

In this my answer I never stated, that Pd will precipitate on addition of sodium-meta-bisulfite, instead I talked about complex sulfito-salts of Pd, like Na2[Pd(SO3)2]*2H2O, which are formed, if enough sodium sulfite(Na2SO3; 2 moles per gram-equivalent of Pd) is added to Pd(II) in a neutral or only slightly alkaline medium. The concentrated Pd-nitrate-solution mentioned above probably contains also a lot of acid, which will protonate the sulfite-anions to hypothetical sulfurous acid (H2SO3), which decomposes immediately into gaseous sulfur-dioxide (SO2) and water. It is true, the complex Pd-sulfito-salt Na2[Pd(SO3)2]*2H2O is only sparingly soluble in water, but it's solubility lies in an order of magnitude of 1 to a few grams Pd per liter, so even in a neutral solution Pd will never be precipitated quantitatively. Therefor I recommend you warmly to proceed as proposed by Harold_V, samuel-a and lazersteve. Just two additional notes: 1.) Be cautious on using ammonium chloride and sodium-chlorate and/or Cl2 together. There is a risk of forming potentially explosive chloro-ammine compounds. Use potassium chloride (KCl) instead of NH4Cl, even if the salt K2PdCl6 may be a bit more soluble than the ammonium salt. 2.) Be sure, that your Pd-solution before precipitation contains at least 6 moles of HCl per gram-equivalent of Pd. This corresponds to about 6 ml 32% HCl for every 1 gram of Pd.

Regards, freechemist


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## kjavanb123 (Jun 1, 2011)

Thanks freechemist for ur info. I have grinded another cat same model and type car and it weighs 1100grams. I have prepared an agitator, a 5liter beaker, gas burner, and i am gonna let it roll at more than 300rpm, for at least 2 hrs, at temprature of 80c. Now my question, in order to fully dissolve 1kg of grinded cat, i am gonna use 2 liters of acid and peroxide in ratio of 10:1. Now I can add let's say 10 cats grinded to a larger stainless steel beaker but my acid usage and therefore my zinc usage will increase, or should I leach one cat and use the same solution to leach another cats to reach 10 cats? Another word, time and gas prices vs. acid zinc prices?

Thanks
Kev


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## qst42know (Jun 1, 2011)

> stainless steel beaker



What acid were you thinking of using in stainless?


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## kjavanb123 (Jun 2, 2011)

qst,

I am using hcl and h2o2 in my 5 liter pyrex beaker, is this how big refiners do it? grind the cats, then leach it with Aqua Peroxide? I assume the more acid usage means more zinc usage in cementing right? 

thanks
Kev


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## Palladium (Jun 2, 2011)

I am totally lost here. Could you run that by me again? What are you trying to do? If you wouldn't mind explain the experiment your trying to do in detail to help us better understand and help you.


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## kjavanb123 (Jun 3, 2011)

I have read an article about grinding the cat and agitate it at 300rpm at 80c for 2hrs would recover 97% Pt and Pd, and I use hcl+h202 for my leaching agent, however the more cats get grinded the more acid requires to be able to dissolve them, and the more acid usage I assume would mean more zinc usage for cementing it. I was curios is this how big refiners do it?


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## kjavanb123 (Jun 3, 2011)

Also, I read that combination acid of hcl and h202 does NOT dissolve Rhodium in catalytic converter, what happens if i add H2S04 to the hcl and h202 mix? so i can get all 3 pgms inside the cat in one shot.

Thanks
Kev


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