elementcollector1
International Hazard
Posts: 2684
Registered: 28-12-2011
Location: The Known Universe
Member Is Offline
Mood: Molten
|
|
Praseodymium silicate
I recently made a visit to Seattle Pottery Supply, and happened upon the oddest thing. A colored glaze, that claimed it got its bright yellow
coloration from a mixture of praseodymium and zirconium silicates (the actual chemical listing was "PrZrSi", but I don't think that's correct).
How do I get the praseodymium in solution from this odd substance?
Elements Collected:52/87
Latest Acquired: Cl
Next in Line: Nd
|
|
|
blogfast25
International Hazard
Posts: 10562
Registered: 3-2-2008
Location: Neverland
Member Is Offline
Mood: No Mood
|
|
That's stuff is likely to be a mixture of Zircon (ZrSiO4) and Pr oxide, fused or not. Zircon is used as an opacifier in pottery glazes, Pr(III,IV)
oxide as a green colourant. Some bright spark had the idea of killing two birds with one stone.
If the stuff is just a physical (milled, perhaps) mixture of Pr oxide and zircon, then treat it with hot 33 % HCl. This should extract the Pr as
PrCl3, the Zircon will stay behind (becoming white in the process). This should be your first attempt.
If that doesn't work:
Finely grind (if needed). Fuse with NaOH or KOH (1 w. part of the stuff + 2 to 3 w. parts alkali) for about 30 mins on medium heat. That 'splits' the
Zircon into Na (or K) zirconate and Na (or K) silicate. The Pr oxide remains unaffected (Pr is not amphoteric).
Treat the cooled fusion product with water, simmer for a while, cool and allow to stand, decant off supernatant liquid. Gently dry the solids ('frit')
if need be. Or filter off solids, wash them, them gently dry.
The wet 'frit' is then treated with hot 33 % HCl, which will dissolve the Pr as PrCl3, the Zr as ZrOCl2. The Si stays behind as SiO2. Filter.
See how you go with that and I'll come up with an idea to separate the Pr and Zr.
Bear in mind that Pr(III,IV) oxide oxidises HCl to Cl2: ventilation, please.
[Edited on 21-6-2015 by blogfast25]
|
|
|
Sulaiman
International Hazard
Posts: 3627
Registered: 8-2-2015
Location: 3rd rock from the sun
Member Is Offline
|
|
I have no experience in this area but looking at Wikipedia entries for zirconium and praseodymium,
maybe praseodymium oxide (see post above) is attracted to a magnet much more than ZrSiO4 ?
if so then finely grinding the mixture may allow separation with just a magnet
|
|
|
blogfast25
International Hazard
Posts: 10562
Registered: 3-2-2008
Location: Neverland
Member Is Offline
Mood: No Mood
|
|
Quote: Originally posted by Sulaiman  | I have no experience in this area but looking at Wikipedia entries for zirconium and praseodymium,
maybe praseodymium oxide (see post above) is attracted to a magnet much more than ZrSiO4 ?
if so then finely grinding the mixture may allow separation with just a magnet |
It's worth a try. Obtaining complete separation would be difficult though. And it would only work in the case of a simple physical mixture of the two.
Also, I'm not sure Pr(III,IV) oxide is magnetic or magnetic enough.
|
|
|
Sulaiman
International Hazard
Posts: 3627
Registered: 8-2-2015
Location: 3rd rock from the sun
Member Is Offline
|
|
all unknown to me, but worth a try as it is so simple
and if it does not work nothing is lost
once the pigment is reacted with an acid or base, for example,
separation could become quite difficult if the 'wrong' initial reactant is used.
|
|
|
elementcollector1
International Hazard
Posts: 2684
Registered: 28-12-2011
Location: The Known Universe
Member Is Offline
Mood: Molten
|
|
I actually decided to use diluted H2SO4 and a little bit of H2O2. So far, the solution is the same color
as the remaining yellow powder (which seems to be nearly all of it), and the solution seems to bubble slightly.
Elements Collected:52/87
Latest Acquired: Cl
Next in Line: Nd
|
|
|
blogfast25
International Hazard
Posts: 10562
Registered: 3-2-2008
Location: Neverland
Member Is Offline
Mood: No Mood
|
|
| Quote: Originally posted by elementcollector1 | | I actually decided to use diluted H2SO4 and a little bit of H2O2. So far, the solution is the same color
as the remaining yellow powder (which seems to be nearly all of it), and the solution seems to bubble slightly. |
Dilute H2O2 should have no effect on something like that, IMHO.
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
