Hello Georges and others interested,

>I have attempted to extract oxygen from epidote using the Ni-vessel and
>BrF5 method. I have heated the vessels at 500 C overnight. From my review
>of literature, no special treatment has been described for epidote oxygen
>extraction using the BrF5 method. I have not produced more than 5% of the
>expected yield of O2. X-Ray diffraction confirmed it was epidote.
>
>Is there a trick I missed for epidote?
>

The advice of James Farquhar is correct, epidote is similar to garnet when 
it comes to reacting it with BrF5 or ClF3. To get 100 % yield you need to 
grind it very fine and react it at temperatures of 600 to 625 deg C for 12 
hours or so. The vessels have to be pre-conditioned for these temperatures 
though.

Regards,

Torsten

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Dr. Torsten W. Vennemann
Institut fuer Geochemie
Wilhelmstr. 56
D-72074 Tuebingen
Germany
phone ++49-(0)7071-2974992
Fax ++49-(0)7071-296870
e-mail: [log in to unmask]
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