Appeal No. 1997-1793
Application No. 08/528,044
using the so-called “flame hydrolytic method,” and to a
process for making such a mixed oxide (specification, page 1,
lines 22-30). According to the appellants, the claimed mixed
oxide compositions exhibit improved UV light absorption as
compared with products of the prior art (specification, page
2, lines 17-21; appeal brief, page 4).
The appealed claims are reproduced below:
2. Titanium dioxide powder composition consisting
of a flame hydrolytically prepared iron oxide/titanium
dioxide mixed oxide with a BET surface area of 10 to 150
m /g, which contains 0.5 to 50 wt. % of iron oxide, with2
reference to the total amount, as a component of the
mixed oxide.
3. A process for preparing the titanium dioxide
powder which contains iron oxide according to claim 2
which comprises volatilizing anhydrous iron(III) chloride
together with an inert gas, transferring the volatilized
anhydrous iron(III) chloride to the mixing chamber of a
burner, mixing the volatilized iron(III) chloride in the
burner with hydrogen, air and gaseous titanium
tetrachloride in a ratio which corresponds to the
composition of the iron oxide/titanium dioxide mixed
oxide, burning the 4-component mixture in a reaction
chamber of said burner and separating the solid iron
oxide/titanium dioxide mixed oxide from the gaseous
reaction product.
4. A process as set forth in claim 3 including the
step of removing adhering hydrogen chloride in moist air.
5. A titanium dioxide/iron(III) oxide mixed oxide
powder prepared by the method of claim 3 or claim 4.
2
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