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Author: Subject: Strontium?
12AX7
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[*] posted on 31-3-2005 at 18:27
Strontium?


So uh...how could I make strontium (oxide, carbonate, etc.)? We have some celestite in the house (okay, so it's a beautiful blue mineral, well no one will miss a corner :P ), but what the heck reduces an insoluble sulfate?

From what I can tell, decomposition temperature is uselessly high...

Tim
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[*] posted on 1-4-2005 at 01:32


Celestite is SrSO4, found in tabular crystals, and is the principal ore of strontium. It is similar to anhydrite, CaSO4, and barite, BaSO4, which is the principal ore of barium.

I would think that a method of refining it would be by electrolysis of the molten sulfate, but it is stated as decomposing at 1,580ºC. This temperature, which would result in SrO, is expensive to attain and maintain, and steel-type alloys cannot be used for a vessel. Reaction with HF is another possibility, but rather dangerous and messy.
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[*] posted on 1-4-2005 at 05:34


12AX
If you want the carbonate, search for a post I made in the calcium sulphide post.
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[*] posted on 1-4-2005 at 08:26


Ah, interesting! I may also have to try the carbon or aluminum reduction too :D

Tim
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[*] posted on 1-4-2005 at 09:10


Red road safety flares are supposed to be over 70% Strontium Nitrate. This could be easily done by putting a few in a bucket of boiling water to get a soluble nitrate. If you were to burn the flare first you would end up with the strontium slag as the oxide, sulfate, and carbonate.(just a guess) A dry crushed mixture of the white slag with aluminum might yield the metal through a thermite reduction.



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[*] posted on 1-4-2005 at 16:53


Quote:
Originally posted by Mr. WizardA dry crushed mixture of the white slag with aluminum might yield the metal through a thermite reduction.


The sulfate perhaps, but is Al + (alkaline earth oxide) > Al2O3 + (metal) favorable? Since, those are all pretty high melting point = stable oxides, after all.

Tim
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[*] posted on 1-4-2005 at 19:17


It might cause some reaction, but it wouldn’t work for the oxides, even with aluminum oxide’s high lattice energy.

Doing the calculation for SrO, I got deltaH = +101KJ/mol, deltaS = -3.88J/mol*K, meaning that you’d have a hard time getting any kind of reaction with this particular oxide. Even if you did, the metal you’d get out would mostly be aluminum.

[Edited on 2-4-2005 by neutrino]
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[*] posted on 1-4-2005 at 22:18


It's not practical that's for sure. I did find this though:
The metal can be prepared by electrolysis of the fused chloride mixed with potassium chloride, or is made by reducing strontium oxide with aluminum in a vacuum at a temperature at which strontium distills off. The BP is about 1370C at 760 mm Hg.
Not exactly a self sustaining thermite reaction :-( Anyway the part about the red flares is still a viable source of the nitrate.




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