Appeal No. 1998-2248
Application No. 08/552,407
silica content of potential recycle concentrates.” The gravity
separation scheme results in a much higher concentration of
titanium dioxide and a much lower amount of silica (see Sample
C, page 11, right column, compared with Sample C, page 4, Table
1). Paige also teaches the benefits of installing a
hydrocyclone in the waste stream circuit before gravity
concentration to recover a high-grade titanium ore and that
only the recovered concentrate could be recycled (page 22, left
column, first paragraph, and right column, first two
paragraphs). Finally, Paige teaches waste materials “treated
by gravity concentration to produce a recyclable titanium
concentrate” where the amount of titanium dioxide in the
gravity concentrate ranges from 69 to 90.7 weight % and “should
be recyclable” (page 23).
With regard to the examiner’s rejections applying Paige in
combination with Hildreth against claims reciting the
additional process step of grinding before recycling, our 4
comments above about Paige equally apply. Additionally, we
4Claims 2 and 9, and dependent claims 3 and 10-16,
respectively, recite an additional step of grinding the
recovered titanium dioxide-rich fraction so that at least 50%
of the particles of the fraction are smaller than 0.1 mm.
6
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