Appeal No. 2004-1043
Application No. 09/960,907
µm or less and teach, "the smaller the alumina particles,
the less the tendency to settle out on the bottom of the
cell (col. 5, lines 1-8). An undissolved alumina supply is
maintained to "provide a ready supply of undissolved
alumina for further dissolution [adjacent the anode]" (col.
3, lines 11-22).
It would have been obvious to one having ordinary
skill in the art at the time the invention was made to have
modified the method described by Beck, Steiger et al. and
Berclaz to use alumina particles having the size and
concentration as taught by Beck et al. because the alumina
particles bf that size will not settle to the bottom of the
cell and provide cell protection provided by that
concentration, while also providing a ready supply of
alumina for dissolution.
III. Claims 35-37 and 40-43 are rejected under
35 U.S.C. 103(a) as being unpatentable over Beck
("A NON-CONSUMABLE METAL ANODE FOR PRODUCTION OF
ALUMINUM WITH LOW-TEMPERATURE FLUORIDE MELTS,”
Light Metals 1995, pp. 355-360) in view of
Steiger et al. (U.S. Pat. No. 4,181,583) and in
view of Berclaz (WO 98/53120).
Regarding claim 35, Beck discloses a method for
producing aluminum comprising the following steps (see
entire document):
(a) Providing a molten salt electrolyte at a
temperature less than 900°C having alumina dissolved
therein in an electrolytic cell having an anodic liner,
wherein the liner has walls and a bottom and is
substantially inert to the electrolyte;
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