# Rhodium precipitate



## Riyoso (Mar 9, 2009)

Can anyone tell me how to precipitate rhodium out
of a 96 % sulfuric acid selution contained from 
a honey comb in cats? The same honey combs
were also in a ar selution for 3 days i droped out 
any values with scrap alluminium and got a black 
precipitate but dont know what it is but does not
disolve in any acid.I would appreciate any 
comments.


Riyoso


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## Lou (Mar 9, 2009)

Zinc will precipitate rhodium from sulfuric acid solution.


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## Irons (Mar 10, 2009)

Lou said:


> Zinc will precipitate rhodium from sulfuric acid solution.



It will take an awful excess of Zinc from 96% H2SO4 and probably a hazmat cleanup crew from the resulting violent reaction.


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## Riyoso (Mar 10, 2009)

So what would you suggest i do Irions ?


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## ps_jb (Mar 10, 2009)

Riyoso said:


> So what would you suggest i do Irions ?



First, neutralize the solution with NaHCO3 - then use either Zn or hydrazine.
Hydrazine is very powerful reduction agent - so be sure that there is no any base metals, like copper, iron etc in your solution


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## Lou (Mar 10, 2009)

Sorry, guess I should be more clear.


Zinc will precipitate rhodium from a sulfuric acid *solution*.

Which means dilute it down. Then you can adjust the pH to 3-4 with a suitable base, like NaOH (carbonate also works, but it's also prone to foamover every bit as much as zinc dissolution is).

Avoid hydrazine until all else fails.


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## Riyoso (Mar 10, 2009)

Thanks ill try it out and see how it works.


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## Irons (Mar 11, 2009)

Lou said:


> Sorry, guess I should be more clear.
> 
> 
> Zinc will precipitate rhodium from a sulfuric acid *solution*.
> ...



One reason that I have become cautious in making suggestions is that in the beginning, I assumed that the board members had basic chemistry skills and understood the ramifications.
Obviously, even I don't always understand the consequences of trying to work with elements which don't like to go into solution, as you well know.

So, now I keep my mouth shut, except in cases where there might be a misunderstanding.

Not to be critical of Lou, his understanding of Chemistry exceeds mine by a long shot.


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## markqf1 (Mar 18, 2009)

Mmmm,
Basic chemistry skills?

I think I went to school with a guy that had a pair of those.  


Mark


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