Appeal No. 96-2884
Application No. 08/181,997
36). We do not find this argument persuasive. With respect to the claims directed to iron
carbide and to iron carbide containing a few impurities, Okamura teaches that the product
produced is composed of iron carbide alone, or iron carbide and iron oxide and/or elemental
carbon. When only iron carbide is produced, one would expect the product to be of high
purity. Although, Okamura does not expressly disclose that the product produced is only
Fe C, and the use of separate reaction zones, in cases of this type, where a person having
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ordinary skill would have reason to believe that the claimed and prior art processes are
substantially identical, the burden of persuasion shifts to appellant “to prove that the subject
matter shown to be in the prior art does not possess the characteristic relied on.” In re Best,
562 F.2d at 1255, 195 USPQ at 433. Herein, appellant has made no direct comparison of
his claimed process with that of Okamura’s process, nor has he shown that the
concentrations of carbonizing and reducing agents are different than that of the prior art.
Appellant urges that one of ordinary skill in the art would not combine Stephens
and Okamura to solve problems addressed by present invention. The examiner relied upon
Stephens for two reasons: (1) to use a fluidized bed and (2) to preheat the feed. Okamura
teaches preheating the iron (column 1, lines 52-58) and in our view the use of a fluidized bed
in the conversion of an iron material to iron carbide would have been prima facie obvious in
view of Stephens teachings. Appellants do not controvert either of these positions. Rather
they address the examiner’s arguments wherein the examiner attempted to arrive at the
claimed invention by relying upon Stephens teachings using a five component gas for
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