Appeal 2007-2124
Application 10/175,515
6. The basic solution is combined with an acid solution containing zirconyl
ion to precipitate the zirconyl tungstate matrix (Ehrhardt, col. 3, ll. 24-27
and 60-68).
7. “It is preferable to slowly add the basic tungsten solution to the acid
solution . . . to promote formation of zirconyl tungstate. This is because of
the tendency of the zirconyl cation to form zirconium hydroxide” which is
undesirable (Ehrhardt, col. 4, ll. 5-12).
8. After the zirconyl tungstate matrix is precipitated, the pH of the slurry
comprising the matrix is adjusted to from 5 to 7 using a base such as sodium
hydroxide to prevent the zirconyl tungstate from re-dissolving (Ehrhardt,
col. 4, ll. 19-23).
9. “Any zirconium hydroxide which forms from the excess zirconyl cation
used as described above, may precipitate when the slurry is adjusted to a
basic pH. This precipitate may remain associated with the matrix and adsorb
any solubilized tungsten released from the matrix which would otherwise
contaminate the eluate” (Ehrhardt, col. 4, ll. 23-29).
10. The matrix material may be transferred to an empty container, such as a
glass column used in standard chromatography, for eluting and harvesting
the daughter compound Re-188 (Ehrhardt, col. 4, ll. 40-47).
DISCUSSION
The dispute in this appeal turns on the proper interpretation of the
phrase “inorganic layered hydroxide.” The Examiner contends that Ehrhardt
teaches a tungsten compound which contains hydroxide, meeting the
limitation in claim 1 of an “inorganic layered hydroxide” (Answer 3-4).
Appellants assert that the Examiner improperly interprets the claimed
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