# separation of pgm from each other(pt,pd,rh)



## arthur kierski (May 17, 2008)

i have a few grams of these 3 metals and made a solution of hno3+h2o---1:1---to dissolve the pd----whem i tried to separate pt from rh i noticed that the nitric did not dissolved all the pd ---what happened?


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## Lou (May 17, 2008)

Sometimes that happens when the Pd ions build up too much in solution. You can try a.) adding more water and more nitric, and b.) heat. That should put it all into a very brown solution. Rinse the powder and give it a boil with more nitric, looking for any colour change. It should be slightly yellow (indicative of decomposing HNO3 and trace Pd cation). Rinse and you will have Pt/Rh mixture. EDIT: the Pd solution should be boiled with HCl to expel any nitric acid, then treated like the Pt in terms of salt formation and salt reduction.

Fuse the Pt/Rh in bisulfate. The Pt will be unaffected, the rhodium will form its (III) sulfate. Filter and rinse till filtrate runs clear. You have rhodium plating solution now (best you evaporate to the crystal, and recrystallise). The Pt may or may not be contaminated with other metals. Probably not if it came from a converter. Just dissolve in aqua regia, make the hexachloroplatinate ammonium salt, and reduce however you feel like.



Cheers,
Lou


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## arthur kierski (May 17, 2008)

thanks lou once again-----i am going to do exactly as you described to me because this happens to me often and i get fed up with having to repeat the process without knowing what happened


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## Lou (May 17, 2008)

Aw, don't tell me thanks, send me thanks! Lou wouldn't mind some platinum or some rhodium. Shall I tell you when my birthday is near? 8) :lol: 

Honestly though, glad to help. If I can't figure it out, I'm certain Steve or _particularly _Irons can!


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