# Palladium salt calcining problems



## inspector071 (Apr 27, 2017)

I had set down precious metal recovering and refining a couple of years ago after moving, but I've gotten some of the stuff back out again now that I have time and space to work with it. I've got a palladium salt that wasn't dissolving in concentrated ammonium hydroxide. It was yellow/orange, not dissimilar from the color of ammonium hexachloroplatinate, except that this was left over from dissolving the brick red ammonium hexachloropalladate in a re-refining step. In getting it back out, the first step I tried was calcining. It melted into a sludge and began evolving ammonium chloride. It was threatening to get messy, so I allowed it to cool and dissolved it in conc. HCl. It dissolved, with the evolution of some gas, but then reprecipitated as a salt that resembled ammonium hexachloropalladate. I filtered this off, attempted to calcine it, but still it did not want to calcine effectively. It melted, evolving more ammonium chloride. I let it cool, and noticed it had become a dark brown solid. If this solid still contains ammonium chloride, but doesn't want to calcine well, what would be the best way to get it back into solution and precipitate it as a known salt, or get it into solution and cement with zinc?


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## Lino1406 (Apr 27, 2017)

Hot AR. This story reminds me yellow hexachloroplatinate in small "original" packages, part of which was not dissolving even in AR (feel free to guess why)


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