Appeal No. 2004-1043
Application No. 09/960,907
Steiger et al. disclose a method for producing
aluminum, wherein the startup method includes the steps of
either charging the cell with molten electrolyte or
charging the cell before pre-heating with solid
electrolyte, which melts as the cell is heated to its
operating temperature (col. 13, lines 5-13). When solid
electrolyte is added, the cell is heated using heaters
placed on the bottom of the cell.
It would have been obvious to one having ordinary
skill in the art at the time the invention was made to have
modified the startup method of Beck to add solid
electrolyte to the cell and heating it up to melt the
electrolyte as taught by Steiger et al. because Steiger et
al. demonstrate that the method of charging the cell with
molten electrolyte and melting a charge of solid
electrolyte within the cell during heat-up can be used
equivalently.
Regarding claim 35, Berclaz discloses a method for
producing aluminum using a cell that has an air space 52 to
adjust the temperature of the cell by supplying heating or
cooling gas to the space 52 (page 26, lines 5-36; fig. 6).
When a gas is not passed through the space 52, the space
acts as a thermal insulating space (page 26, lines 25-29).
Further, Berclaz discloses, "during cell start up, the
cathode 30 can be heated by passing hot gas through space
52" (p. 26, lines 32-33).
It would have been obvious to one having ordinary
skill in the art at the time the invention was made to have
modified the cell start up method used by Beck to use
heating gas to heat the cell at start up as taught by
Berclaz because using a heating gas positioned below the
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