Are you talking sublimation?. That must take really expensive equipment to do. Or is it gas phase transport and deposition of the metal salts?. :shock:Lou said:Gold dendrites can indeed be grown, as can for all the platinum group metals. Silver doesn't appreciably gas phase transport like Os, Ir, Ru, Re, Pt, Pd, Rh, and Au do.
Gas phase grown large crystals of these metals are the purest sources of the metal on Earth, over zone-refined material and induction levitation.
In my limited experience, the slower the crystals grow, the bigger they ultimately become. For example a precipitation of gold with ammonium oxalate done at near boiling temperatures will be fast, but will produce much smaller crystals than if the precipitation is done at room temperature over several days with more oxalic acid and less ammonia, and the crystals can grow much larger. The larger, slowly precipitated crystals seem to be slightly purer (and much easier to wash well).Harold_V said:Thanks, Lou. I was speaking from my very limited knowledge on the subject, and with the knowledge that the Wohwill cell produces nodules.
Can you possibly explain why that is?
Off the subject, but related, in my many years of precipitating gold, on no more than about three occasions, I precipitated small crystals. Had they been much larger, they'd have displayed the true color of gold, as we know it. These were small enough to scatter light to some degree, so they weren't quite as shiny and brilliant gold colored, but much more so than the general blond material that was so familiar. It would be interesting to understand the reason that happened.
Harold
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