Appeal No. 2005-0657
Application No. 10/136,984
burning zone as it travels from the kiln shell into the cooler
”to ensure good commingling” (col. 6, ll. 36-40). Finally, Oates
teaches that adding the extender at the upstream end of the
cooler “represents merely one location” where the extender may be
introduced (col. 8, ll. 8-9).
Obviousness is tested by what the combined teachings of the
references would have suggested to one of ordinary skill in the
art. See In re Young, 927 F.2d 588, 591, 18 USPQ2d 1089, 1091
(Fed. Cir. 1991); and In re Keller, 642 F.2d 413, 425, 208 USPQ
871, 881 (CCPA 1981). Here the combined teachings of the
references teach one of ordinary skill in this art to
specifically add slag at the feed end of the rotary kiln, at the
flame or heat end of the rotary kiln, in the initial cooling zone
at the discharge end of the kiln (downstream of the burning zone
24; see Figure 1 of Oates), or at the upstream end of the cooler
adjacent the exit of the kiln, or generally at many locations
(Oates, col. 8, ll. 8-9). The combined teachings of the
references would have suggested to one of ordinary skill in this
art that the optimal entry location of the slag into the kiln
would have depended on the desired residence time, the
calcination or burning temperature, and the time for adequate
mixing or commingling (and thus the length and size of the kiln
7
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