# Need help separating PGMs from ceramic (Zirconia?)



## Ignatz61 (Mar 9, 2008)

I have a small batch of ceramic powder containing PGMs (Not catalytic material). I am trying to get a handle on the quantity of PGMS / gram. Is there a way to dissolve the metals and weigh the powder, the difference in weght from before dissolving being the metal weight?

I was thinking of a roast to about 1000 f 
then digest the metals
then roast again to dry the powder.
BUT what would be the best way to disolve the PGMs?

Am I barking up the wrong tree? My goal is to get a good idea of the percentage of PGMs to determine if it's worth refining larger batches.

Is there a better way to do this analysis? Or should I ante up and pay for an assay? I really would rather tackle this myself though.

I have received great guidance from this forum before,

thanks,
john


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## Lino1406 (Mar 15, 2008)

HF or HF+ HNO3 should separate
between them with minimal weight
loss (of the ceramics)


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## Irons (Mar 15, 2008)

Zirconia can also be fused with NaOH at 650-850 Deg C. to form a soluble salt which can be extracted with water leaving the PGMs as a precipitate.


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## Ignatz61 (Mar 16, 2008)

I think this may work better than I thought!!
So, How do I proceed?
Mix NaOH powder with my ground up zirconia "bake" at 800 degree C then disolve in water leaving behind the PGMs?
How long should I leave it in the heat? Will it "melt" together like a boric flux would?
This is great! If it is truly that easy.
Thanks,
John


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## Ignatz61 (Apr 2, 2008)

Ok, can someone (Irons?) tell me if I have missed anything with my process. I am new at this but I learn fast.
I ground up the zirconia/platinum to a fine powder.
I mixed it with sodium Hydroxide powder and baked for 2 hours at 1472 F.
I did this dry the first time and it made a block that did not disolve well at all. I dried and crushed this batch again.
NEXT I mixed the powder, lye and this time added water to get the sodium HYDROXIDE to saturate the powder prior to baking.
this time it was pretty much water soluable but still have a fine silt in the bottom. The liquid turned green
I diluted and filtered the liquid and have the fine brown silt and some bits of powder that was not crushed small enough I guess and some dark spots I hope will be the PT. 
I baked it in a Stainless steel dish so I may have some residue from the stainless.
Can I wash this with HCL to dissolve any base metals etc..?
Any advise as always would be most appreciated!
thanks,
JOHN


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## Lou (Apr 2, 2008)

Nickel is best for alkali fusions. 


It doesn't need to be mixed that well, the sodium hydroxide will melt, and as it does it will dissolve everything but the platinum. After it's all cooled down, you should be able to separate out the Pt powder from the (I suppose) zircanate? 

I've never had to fuse zirconia. 

My suggestion would be to just pull the Pt out with a halogen gas at high temperature, leaving the zircon behind.


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