# lye in my mixed black powder



## kjavanb123 (Jun 23, 2011)

All,

After cementing AP solution with zinc powder the solution turned black, so i diluted with water, and I let it sit for 24hrs to settle, in order to avoid re-dissolving the PGMs in the acidic solution I added some dry lye thinking it would be mixed with water in the solution but as you can see from the picture somewhat it got mixed up with the black powder. I tried to boil the solution few times thinking it would dissolve in water, but still some lye left. If I add acid it might dissolve Pd. Any ideas?

Here is the solid residue seems to be black powder and lye.


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## Lou (Jun 23, 2011)

Your picture didn't post. Lye will easily dissolve in water.


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## samuel-a (Jun 23, 2011)

Can't see pic Kev.

It is very much depanded on pH, if you saturated the solution with zinc, pH can run higher then 3 and take time (if at all) for free h2o to dissolve the lye.

Consequence, if you had lots of zinc dissolved, you shouldn't be worry about Pd dissolving back.
As Lou said, add some water.


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## Irons (Jun 24, 2011)

Zinc Hydroxide? That might explain the white precipitate.


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## Lou (Jun 24, 2011)

Extra lye will dissolve the hydrous zinc oxide and form a colorless complex.


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