Appeal No. 2000-1849
Application No. 08/988,481
during the melt processing of the glass composition, the
manganese compound being included to provide 0.1 to 1.0 wt. %
manganese oxide as MnO weight percent based on the total
2
weight of the glass composition.
The examiner relies upon the following references as
evidence of obviousness:
Barrett et al. (Barrett) 4,341,566 Jul. 27, 1982
Jones et al. (Jones) 5,346,867 Sep. 13, 1994
Appellants' claimed invention is directed to a nitrate/
nitrite-free method for retarding the volatilization of
selenium in the preparation of a glass composition. The method
entails including the recited amount of MnO during the melt
2
processing
of the glass composition. According to appellants'
specification, "[w]e have unexpectedly found that the manganese
compound, e.g., used in the gray glass of Jones '867 to retain
selenium, also has sufficient oxidizing ability which allows
nitrates and nitrites
to be avoided throughout the manufacturing process of the
selenium containing glass, contrary to what was formerly
believed" (page 2, last paragraph). The specification explains
in the following sentence that "[t]his also allows the amount
of sodium sulfate to be desirably increased over that which
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