Appeal No. 2004-1043
Application No. 09/960,907
aluminum-producing electrolytic cell regardless of cell
layout.
H. The Steiger Reference (XII.H, pages 38-41)
i. Steiger is concerned with a method of internally
heating a cell (XII.H, page 38)
Appellant states that Applicant's invention is
patentable over the prior art because Steiger teaches the
application of heat inside the cell (see Appellant’s Brief,
p. 38, first paragraph).
Regarding claims 35-37 and 40-43, the Beck paper,
Berclaz and Steiger all teach the process of
electrolytically producing aluminum from alumina.
Additionally, Beck, the primary reference, discloses the
following method including a startup method:
Heatup to operating temperature of 750°C and
complete melting of electrolyte took five hours.
Two hours of electrolysis at 300 amperes
followed. (see Beck paper, p. 359, col. 2, second
paragraph)
The Beck paper does not explicitly disclose whether
the electrolyte was added to the cell before or after it
was melted. Since the entire cell operates at the
operating temperature, the addition of solid electrolyte
before melting is implied. However, the Steiger reference
was relied upon to show that the order in which the heating
and addition takes place is irrelevant. Steiger teaches,
"The cell chamber is charged with molten aluminum and
electrolyte . . . [or] the cell is charged before heat-up
with powdered electrolyte, e.g., solid cryolite, which
melts as the cell is heated to its operating temperature"
(see US ‘583, col. 13, lines 5-13). One skilled in the art
35
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