# precipitating



## Anonymous (Jun 17, 2008)

what do i use to precipitate pgms out of aqua regia. I am somewhat confused. I have been told to use zinc or hydrazine. also what do i do with the dropped metals after they are filtered and washed. Thanks


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## Harold_V (Jun 18, 2008)

Zinc will reduce all of the metals, including copper -----it is not selective. Don't know about hydrazine---never used it.

It might help if you mentioned what metals you desire to recover. The process for each one is not the same, and it's a good idea to precipitate them in proper order. For example, a solution that bears both platinum and palladium, platinum is the first to be recovered. 

Harold


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## Lino1406 (Jun 19, 2008)

is risky with nitric


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## Anonymous (Jun 19, 2008)

I am trying to extract the pgms out of honeycombs from cats. I have been following peoples progress on this forum. I plan to do this outside with proper safety precautions so no worries


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## Harold_V (Jun 20, 2008)

All of my experiences with the Pt. metals (platinum and palladium) came from processing wastes from dental appliances and jewelry the sole exception was one excursion with a small amount of pellets from a cat.

Everything I processed was accomplished with AR, evaporated, filtered and precipitated with ammonium chloride (platinum) and sodium chlorate (palladium). Hoke discusses the procedures at length in her book. I hesitate to say anything more because of my limited knowledge of chemistry and the platinum metals. 

Regardless of your intentions, you would benefit greatly by reading Hoke's book, assuming you are not well versed in chemistry. 

Harold


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