# precipitation of a yellow powder



## arthur kierski (Apr 28, 2008)

whem using ar and adding hcl for 4times in order to eliminate excess nitric acid i filtrated and before adding amoniumm chloride to the solution a yellow powder together with a brownish-yellow powder precipitated---------note :this is from a french Renault catalyst
can anyone tell me what happened?


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## Palladium (Apr 28, 2008)

Arthur, Aqua regia is 1 part 70% Nitric Acid, 3 parts Muriatic Acid (HCL)
If you need to neturalize the nitric acid you need to evaporate the excess nitric or add urea.


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## Palladium (Apr 28, 2008)

arthur kierski said:


> whem using ar and adding hcl for 4times in order to eliminate excess nitric acid i filtrated and before adding amoniumm chloride to the solution



Now i see, you are trying to recover this from cat"s. It needs to be concentrated to get the PGM to drop so just evaporate the excess Nitric by heating it. 

I think that's right. Anybody ????????


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## arthur kierski (Apr 28, 2008)

paladium;i think you did not understand what i meant
Ifiltrated the ar and the filtrate before adding nh4cl to precipitate pt -already a yellow-brownish powder come down----i filtrated (took out the yellow powder) and added nh4cl and yellow h2ptcl6 precipitated-----
i would like to know what was the yellow powder which precipitated spontaneouly??


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## lazersteve (Apr 28, 2008)

Art,

Dissolve a small sample in water and test with stannous choride to determine if it's a PGM.

Steve


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## Palladium (Apr 28, 2008)

Ahhhh, I see what you are saying. I thought you meant you added 4 parts hcl trying to get rid of the excess nitric.


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## arthur kierski (Apr 28, 2008)

lazersteve, tomorrow i wil test with sncl2 and will give you a reply---thank you again


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## arthur kierski (Apr 29, 2008)

Lazer Steve----i did the test with sncl2 and it gave a redish collor which i assumed to be platinum -the yellow powder reacted with hidrazine and gave 0.48grams of greysh platinum------to---the liquid left from the nh4cl precipitation which gave yellow h2ptcl6 was added iron powder and instead of precipitating black rh and pd powder, what came down was a yellowishgreen powder which george g. gadja in his book (gold refining) says it is rh----------
another topic --- tomorow i will make a test with a rh sulphate solution (it contains only rh) with sncl2 ---to see what color comes out---i will pass to you----do you have an idea of what collor should be?


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## lazersteve (Apr 30, 2008)

Here is the Rhodium Test:

Rh Test

The sources I've seen say the Yellow-Green is Pt contaminated with Rh. 

Steve


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## arthur kierski (Apr 30, 2008)

yes , it is pt contaminated with rh---your source is correct----what is buffling me is that from one (renault) catalyst i extracted in the moment-2.31grams of pt and have still all this yellow-green pwder left which today i will transform into metal with hidrazine--and tell you the total result--this 2.31 grams of pt might be pt +rh---and todays grams which i will colect also is pt contaminated with rh--------------after is easy to separate the pt from rh-----------------no pd in this cat


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## arthur kierski (May 1, 2008)

the renault catalist gave 3.60grams of pt +rh----it gave no pd--------
the pt +rh will be separated from each other(i made some mess )---the catalyst substrate weighted 1.135grams---1,135kilos---aprox2.5pounds


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## Froggy (May 2, 2008)

What was your rh amount,, thx Frog


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