Ex Parte Beck

Board of Patent Appeals and Interferences

Aug 12, 2004

09960907 (B.P.A.I. Aug. 12, 2004)

The opinion in support of the decision being entered today was
not written for publication and is not precedent of the Board.

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
____________

Ex parte THEODORE R. BECK

____________

Appeal No. 2004-1043
Application No. 09/960,907
____________

ON BRIEF
____________

Before TIMM, JEFFREY T.SMITH and PAWLIKOWSKI, Administrative
Patent Judges.
PAWLIKOWSKI, Administrative Patent Judge.

DECISION ON APPEAL

This is a decision on appeal under 35 U.S.C. § 134
from the examiner’s final rejection of claims 1-43.
Claims 1, 10, 18, 27 and 35 are representative of the
subject matter on appeal and are set forth below:
1. An improved method of producing
aluminum in an electrolytic cell containing
alumina dissolved in an electrolyte, the
method comprising the steps of:
(a) providing a molten salt
electrolytic at a temperature less than
900ºC having alumina dissolved therein in an
Appeal No. 2004-1043
Application No. 09/960,907

2
electrolytic cell having a metallic liner
which is anodic for containing said
electrolyte, said liner having a bottom and
walls extending upwardly from said bottom,
said liner being substantially inert with
respect to said molten electrolyte;
(b) providing a plurality of non-
consumable anodes and cathodes disposed in
said electrolyte;
(c) passing an electric current through
said liner and anodes through said
electrolyte to said cathodes, depositing
aluminum on said cathodes, and generating
oxygen bubbles at the anodes, said bubbles
stirring said electrolyte;
(d) periodically reducing electric
current flow to said cell for extended
periods; and
(e) maintaining said electrolyte and
aluminum in said cell in a molten condition
during said extended periods of reduced
current flow by application of heat to said
bottom for purposes of heating said cell.

10. A method of efficiently operating a
low temperature cell for the electrolytic
production of aluminum from alumina
dissolved in a molten salt electrolyte in a
manner which is regulated to consume
electrical power in a more cost-effective
basis, the method comprising the step of:
(a) providing a molten salt electrolyte
at a temperature less than 900ºC having
alumina dissolved therein in an electrolytic
cell having a metallic liner which is anodic
for containing said electrolyte, said liner
having a bottom and walls extending upwardly
from said bottom, said liner being
substantially inert with respect to said
molten electrolyte;
(b) providing a plurality of non-
consumable anodes disposed substantially
vertically in said electrolyte and a
plurality of cathodes disposed vertically in
said electrolyte, said anodes and said
Appeal No. 2004-1043
Application No. 09/960,907

3
cathodes arranged in alternating
relationship;
(c) passing an electric current through
said liner and anodes sand through said
electrolyte to said cathodes, depositing
aluminum on said cathodes, and generating
oxygen bubbles at the anodes, said bubbles
stirring said electrolyte;
(d) periodically reducing electric
current flow to said cell for extended
periods; and
(e) maintaining said electrolyte and
aluminum in said cell in a molten condition
during said extended periods of reduced
current flow by application of heat to said
bottom for purposes of heating said cell.

18. An improved method of producing
aluminum in an electrolytic cell containing
alumina dissolved in an electrolyte, the
method comprising the steps of:
(a) providing a molten salt electrolyte
at a temperature less than 900ºC having
alumina dissolved therein in an electrolytic
cell having a metallic liner which is anodic
for containing said electrolyte, said liner
having a bottom having an outside surface
and having walls extending upwardly from
said bottom, said liner being substantially
inert with respect to said molten
electrolyte;
(b) providing a plurality of non-
consumable anodes and cathodes disposed in
said electrolyte;
(c) passing an electric current through
said liner and anodes and through said
electrolyte to said cathodes, depositing
aluminum on said cathodes, and generating
oxygen bubbles at the anodes, said bubbles
stirring said electrolyte;
(d) removing heat from said cell
through said bottom of said liner by passing
an air sweep from outside said cell over
said outside surface of said bottom to
remove heat from said bottom to provided a
heated air sweep; and
Appeal No. 2004-1043
Application No. 09/960,907

4
(e) discharging said heated air sweep
to the atmosphere outside said cell thereby
maintaining said cell at said temperature.

27. A method of efficiently operating a
low temperature cell for the electrolytic
production of aluminum from alumina
dissolved in a molten salt electrolyte in
the method comprising the steps of:
(a) providing a molten salt electrolyte
at a temperature less than 900ºC having
alumina dissolved therein in an electrolytic
cell having a metallic liner which is anodic
for containing said electrolyte, said liner
having a bottom having an outside surface
and have wall extending upwardly from said
bottom, said liner being substantially inert
with respect to said molten electrolyte;
(b) providing a plurality of non-
consumable anodes disposed substantially
vertically in said electrolyte and a
plurality of cathodes disposed vertically in
said electrolyte, said anodes and said
cathodes arranged in alternating
relationship;
(c) passing an electric current through
said liner and anodes and through said
electrolyte to said cathodes, depositing
aluminum on said cathodes, and generating
oxygen bubbles at the anodes, said bubbles
stirring said electrolyte;
(d) removing heat from said cell
through said bottom of said liner by passing
an air sweep over said outside surface of
said bottom to provide a heated air sweep;
(e) discharging said heated air sweep
outside said cell;
(f) sensing the temperature of said
electrolyte to provide a reading;
(g) relying said reading to a
controller;
(h) in said controller, comparing said
reading to a set reading to provide a
comparison; and
(i) in response to said comparison,
increasing, decreasing or maintaining air
Appeal No. 2004-1043
Application No. 09/960,907

5
flow rate in said air sweep to maintain said
cell at temperature.

35. An improved method for startup of a
low temperature, electrolyte cell for
producing aluminum from alumina dissolved in
an electrolyte at less than 900ºC, the
method comprising the steps of:
(a) providing an electrolytic cell
having a metal liner for containing
electrolyte, said liner having a bottom
having an outside surface and having walls
extending upwardly from said bottom;
(b) providing a plurality of non-
consumable anodes and cathodes disposed in
said electrolyte;
(c) adding solid electrolyte and
alumina to said cell;
(d) placing at least one heater
adjacent said outside of said bottom;
(e) adding heat to said bottom until
said solid electrolyte is melted; and
(f) when said electrolyte is in molten
form, passing an electric current through
said anodes and through said electrolyte to
said cathodes, thereby depositing aluminum
at said cathodes and generating oxygen
bubbles at the anodes.

The examiner relies on the follow references as
evidence of unpatentability:
Weaver 2,062,340 Dec. 01, 1936
Steiger et al. (Steiger) 4,181,583 Jan. 01, 1980
Beck et al. (Beck) 4,865,701 Sep. 12, 1989
Berclaz WO 98/531120 Nov. 26, 1998
Beck, T.R., “A Non-Consumable Metal Anode For Production Of
Aluminum With Low-Temperature Fluoride Melts” (1995),
pp. 355-360.

Claims 1-3, 6-12, 15-20, 23-29 and 32-34 stand
rejected under 35 U.S.C. § 103 as being unpatentable over
Beck in view of Weaver and in view of Berclaz.
Appeal No. 2004-1043
Application No. 09/960,907

6
Claims 4, 5, 13, 14, 21, 22, 30, 31 and 39 stand
rejected under 35 U.S.C. § 103 as being unpatentable over
Beck (an non-consumable metal anode for production of
aluminum with low-temperature fluoride melts) in view of
Weaver, and in view of Berclaz, and further in view of Beck
(U.S. Patent 4,865,701).
Claims 35-37 and 40-43 stand rejected under 35 U.S.C.
§ 103 as being unpatentable as being unpatentable over Beck
in view of Steiger and in view of Berclaz.
Claims 38 and 39 stand rejected under 35 U.S.C. § 103
as being unpatentable over Beck in view of Steiger and view
of Berclaz and further in Beck (U.S. Patent 4,865,701).
On page 5 of the Brief, appellant states that claims
18-34 and 35-43 are claims of different scope from claims
1-17. Upon our review of appellant’s brief and reply
brief, we observe that appellant argues claims 1, 10, 18,
27, and 35 separately. We accordingly considered these
claims in this appeal. 37 CFR § 1.192(c)(7 and 8)(2003).

OPINION
Beginning on page 18 of brief, appellant argues that
the Beck paper is silent with respect to providing periods
with of reduced electrical current flow. At the top of
page 19 of the brief, appellant argues that the invention
provides that during periods of reduced current flow,
electrolyte and aluminum are kept molted by applications of
heat to the bottom of the cell. Appellant also argues that
the invention requires a plurality of anodes. With regard
to claims 18 and 27, appellant argues that these claims
require removal of heat from the cell by passing an air
sweep from outside the cell over the bottom of the cell and
Appeal No. 2004-1043
Application No. 09/960,907

7
discharging the heated air outside the cell. Appellant
argues the Beck paper cell with respect this aspect of the
claimed invention.
Appellant further argues with regard to claim 27 that
claim 27 requires controlling the temperature of
electrolyte using the controller which increases or
decreases the air sweep to control of the temperature in
the cell. Beginning on page 20 of the brief, appellant
discusses the Weaver reference. Appellant argues that with
regard to claims 1 and 10, these claims are patentable over
the combination of the Beck Paper in view of Weaver.
Appellant argues that Weaver does not employ a metallic
liner but instead employs a double refractory liner denoted
as 6 and 7. Appellant argues that because Weaver does not
employ a metallic liner claims 1 and 10 are patentable over
Weaver. Appellant further argues that claims 1 and 10,
heat is supplied to the metallic bottom during periods of
reduced current flow in order to maintain the electrolyte
and aluminum in a molten condition. Appellant argues that
Weaver heats by burning combustible material with a hollow,
cylindrical anode located on top of the electrolyte.
Appellant argues that this is different from the claimed
invention. (Brief, page 20 and 21).
Appellant further argues that claims 1 and 10 are
patentable of the Beck paper and Weaver because the
invention requires a plurality of non-consumable anodes and
cathodes to disposed in the electrolyte. Appellant argues
that Weaver only discloses a layer of molten aluminum 13 as
the cathode. Appellant states that clearly Weaver is
concerned with a different electrolytic cell employing a
molten cathode and is not concerned with non-consumable
Appeal No. 2004-1043
Application No. 09/960,907

8
cathodes as required by appellant’s claims. Thus, for this
reason, appellant argues that the invention is patentable
over Weaver. Appellant further argues that Weaver
discloses and requires the use of a hollow anode whereas
and the claimed does not. At the bottom of page 21,
appellant states that the invention does not use a hollow
anode that rotates to produce agitation. Appellant argues
that the claim provide for agitation by generating oxygen
levels when electric current is passed through liner. On
page 22 of the brief, appellant further argues that Weaver
requires the hollow anode for purposes of heating or
cooling the electrolyte. Appellant states that the
invention as claimed the anode does not function in this
way; that is, heat is added or removed through the metallic
cell bottom. Appellant states that thus even if combined
with Beck, appellant’s invention is patentable over Weaver.
Appellant further argues that with regard to claims 18
and 27, Weaver is silent with respect the use of an air
sweep on the bottom of the cell. On pages 22-23 of the
brief, appellant concludes therefore that the combination
of the Beck paper in view of Weaver does not suggest the
claimed invention. Appellant also argues that there is no
suggestion when essential steps of appellant’s invention
are missing in the references.
Beginning on page 23 of the brief, appellant argues
the Berclaz reference. Appellant submits that the Berclaz
reference is concerned with a different cell than that of
appellant. Appellant states that the claimed metallic
liner which is at anodic potential having a bottom to which
is applied heat for purposes of heating the cell during
period of reduced current flow. Appellant states that
Appeal No. 2004-1043
Application No. 09/960,907

9
Berclaz does not have a metallic liner held at anode
potential. Appellant states that Berclaz is silent with
respect to passing electric current through the metallic
liner and anodes through to the cathodes. Appellant
further argues that Berclaz describes in metallic cell 31
for the cathode material. Appellant states that Berclaz
discloses that the metal shell holds cathode material and
is held at cathode potential. At the bottom of page 24 of
the brief, appellant further argues that Berclaz differs
from the claimed invention and that Berclaz indicates that
heating and cooling is provided to adjust the temperature
of the cathode. At the top of page 25 of the brief,
appellant states that thus the heat is applied to the
cathode at start-up to pre-heat the cathode or, the cathode
is cooled during operation to perform a protective paste.
Appellant argues in his invention, heat is supplied to the
bottom of the cell (not to the cathode) to keep the
electrolyte molten under reduced current operation or heat
is removed though the bottom to control the temperature of
electrolyte during operation. Appellant argues that in his
invention, heat is added and removed from through the metal
bottom of the cell and this is not disclosed in Berclaz.
Finally, appellant argues that Berclaz is concerned with
the different type of electrolytic cell. (Brief, page 25).
On pages 26-33, appellant sets forth further in view
arguments regarding the rejection over the Beck article and
in view Weaver and further Berclaz (Items e, d, f, and g).
We have carefully reviewed this aspect of the brief.

II. The examiner’s position
Appeal No. 2004-1043
Application No. 09/960,907

10
Regarding claims 1,10,18 and 27, 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;
(b) Providing a plurality of non-consumable anodes and
cathodes disposed in the electrolyte;
(c) Passing an electric current through the anodes and
through the electrolyte to the cathodes, depositing
aluminum on the cathodes and. generating oxygen bubbles
that stir the electrolyte.
Regarding claims 2, 11, 19 and 28, Beck discloses the
use of an electrolyte temperature of 750°C (abstract).
Regarding claims 3, 12, 20 and 29, Beck discloses the
use of alkali metal fluorides in the bath including NaF
(introduction).
Regarding claims 8, 15, 23 and 32, Beck uses anodes
and an anodic liner made of Cu-Ni-Fe alloy (p. 359, col.1).
Regarding claims 7, 16, 24 and 33, Beck provides an
example of a cell operated at 0.5 A/cm2 (p. 359, col. 2).
Regarding claims 8, 17, 25 and 34, Beck discloses the
use of titanium diboride cathodes (abstract).
The method of Beck differs from the instant invention
because Beck does not disclose the following:
a. Periodically reducing the electric
current flow to the cell and applying heat
to the bottom of the cell to maintain the
bath in a molten state, as recited in claims
1 and 10;
Appeal No. 2004-1043
Application No. 09/960,907

11
b. A plurality of anodes and a
plurality of cathodes, as recited in claims
9,10, 26 and 27;
b. Removing heat from the cell through
the bottom of the liner by passing air over
the outside-surface of the bottom and
discharging the air, as recited in claims 18
and 27; and
c. Controlling the temperature of the
electrolyte using a controller, as recited
in claim 27.

Regarding claims 1 and 10, Weaver discloses a method
and apparatus for producing aluminum wherein the
temperature is controlled to maintain a preferred bath
temperature and also to operate when "off peak power" can
be used. Weaver uses a hollow anode, through which a
cooling fluid is passed to prevent the temperature from
exceeding the desired temperature range (page 3, col. 2,
lines 53-6O). Weaver also discloses that the electrolysis
can be performed "as an intermittent operation with ‘off
peak power’. . . [where] the anode can be heated by burning
combustible material there within to prevent the freezing
of the bath" (page 3, col. 2, lines 61-74).
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 of Beck to operate the cell
intermittently while maintaining the bath in a molten state
as taught by Weaver because operating the cell only during
"off peak power" times reduces the operating cost of the
operation.
Regarding claims 1, 10, 18 and 27, 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
Appeal No. 2004-1043
Application No. 09/960,907

12
heating or cooling gas to the space 52 (page 26, lines
25-36; 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).
It would have been obvious to one having ordinary
skill in the art at the time the invention was made to have
modified the temperature control pipes in the cell used by
Beck to use heating or cooling gas to control the
temperature as taught by Berclaz because using heating or
cooling gas allows the temperature of the cell to be
controlled and also provides thermal insulation in the form
of an air space when heating or cooling is not necessary.
Regarding claims 9, 10, 26 and 27, 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 of Beck to
use a plurality of cathodes because using a plurality of
cathodes and a plurality of anodes increases the amount of
aluminum that can be produced.
Regarding claim 27, Weaver maintains "a proper
temperature control within very close limits" by using a
temperature sensor and controller (page 4, col.1, lines
1-26).
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 of Beck to use a sensor and controller
as taught by Weaver because the sensor and controller
allows the temperature to be maintained within very close
limits.

II. Claims 4, 5, 13, 14, 21, 22, 30, 31 and 39 are
rejected under 35 U.S.C. 103(a) as being unpatentable over
Appeal No. 2004-1043
Application No. 09/960,907

13
Beck ("A NON-CONSUMABLE METAL ANODE FOR PRODUCTION OF
ALUMINUM WITH LOW-TEMPERATURE FLUORIDE MELTS,"
Light Metals 1995, pp. 355-360) in view of Weaver
(U.S. Pat. No. 2,062,340) and in view of Berclaz
(WO 98/53120), as applied above to claims 1-3,
6-12, 15-20, 23-29 and 32-34, and further in view
of Beck et al. (U.S. Pat. No. 4,865,701).
Beck, Weaver and Berclaz describe a method having the
limitations recited in claims 1-3, 6-12, 15-20, 23-29 and
32-34, of the instant invention, as described above in
section I.
The method described by Beck, Weaver and Berclaz
teaches the electrolytic formation of aluminum from
alumina, differs from the instant invention because they do
not teach the use of 0.2 to 30 wt.% undissolved alumina
particles, as recited in claims 4, 13, 21 and 30, and the
undissolved alumina particles have a particle size in the
range of 1 to 100 µm, as recited in claims 5, 14, 22, 31
and 39.
Regarding claims 4, 13, 21 and 30, Beck et al.
disclose the use of excess alumina at a concentration
within the claimed range of 0.2 to 30 wt.% undissolved
alumina particles (col. 6, lines 1-12).
Regarding claims 5, 14, 22, 31 and 39, Beck et al.
disclose the use of alumina particles having a diameter up
to 100 µm (col. 5, lines 1-8).
Beck et al. disclose the use of alumina particles in
the slurry having a concentration of alumina particles
within the range claimed in claim 38 of the instant
application (col. 6, lines 1-12). Beck et al. also
disclose the use of alumina particles having a size of 100
Appeal No. 2004-1043
Application No. 09/960,907

14
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;
Appeal No. 2004-1043
Application No. 09/960,907

15
(b) Providing a plurality of non-consumable anodes
and cathodes disposed vertically in the electrolyte;
(c) Heating the cell up to operating
temperature and completely melting the
electrolyte; and
(d) Passing an electric current through the anodes
and through the electrolyte to the cathodes, depositing
aluminum on the cathodes and generating oxygen bubbles that
stir the electrolyte.
Regarding claim 36, Beck discloses the use of an
electrolyte temperature of 750°C (abstract).
Regarding claim 37, Beck discloses the use of alkali
metal fluorides in the bath including NaF (introduction).
Regarding claim 40, Beck uses anodes and an anodic
liner made of Cu-Ni-Fe alloy (p. 359, col.1).
Regarding claim 41, Beck provides an example of a cell
operated at 0.5 A/cm2 (p. 359, col. 2).
Regarding claim 42, Beck discloses the use of titanium
diboride cathodes (abstract).
Regarding claim 43, the anodes and cathode are
disposed in an alternating relationship (fig. 10).
The method of Beck differs from the instant invention
because Beck does not disclose the following:
a. Adding solid electrolyte and alumina
to the cell, as recited in claim 35;
b. Placing a heater adjacent to the
bottom of the liner and adding heat to the
bottom until the electrolyte until it is
melted, as recited in claim 35; and
c. A plurality of anodes and a
plurality of cathodes, as recited in~clairn
43;

Appeal No. 2004-1043
Application No. 09/960,907

16
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
Appeal No. 2004-1043
Application No. 09/960,907

17
cell allows the temperature of the cell to be controlled
and also provides thermal insulation in the form of an air
space when heating or cooling is not necessary.

IV. Claims 38-39 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 98153120), as applied above to claims
35-37 and 40-43, and further in view of Beck et al. (U.S.
Pat. No. 4,865,701). (Although claim 39 depends from claim
2, it is treated in this section as though it depended from
claim 35, as explained in the Office action mailed December
12, 2002. Since Applicant has not changed the dependency
from claim 2, but has referred to as part of the group
consisting of claims 35-43 in section VII on page 5 of
Applicant's Appeal Brief, the claim has been treated for
both possibilities as it has been treated since the first
Office action.)
Beck, Steiger et al. and Berclaz describe a method
having the limitations recited in claims 35-37 and 40-43 of
the instant application, as explained above in section Ill.
The method described by Beck, Steiger et al. and
Berclaz differs from the instant invention because they do
not disclose the concentration of the alumina in the
slurry, as recited in claim 38, or the size of the alumina
particles, as recited in claim 39.
Beck et al. disclose the use of alumina particles in
the slurry having a concentration of al umina particles
within the range claimed in claim 38 of the instant
Appeal No. 2004-1043
Application No. 09/960,907

18
application (col. 6, lines 1-12). Beck et al. also disclose
the use of alumina particles having a size of 100 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).
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 of that size will not settle to the bottom of the
cell and provide cell protection provided by that
concentration.

(11) Response to Arguments
A. The Beck Paper (XII.A, pages 18-19)
i. The Beck paper is silent to the claimed periods of
reduced electrical current flow to the cell (XII.A, page
18) and the application of heat to the bottom of the cell
liner during periods of reduced current flow (XII.A, page
19)
Regarding claims 1-17, the Examiner acknowledges that
the primary reference of Beck does not teach the periodic
reduction of current flow to the cell and the application
of heat during the periods of reduced current flow.
However, the Examiner deems that these steps would have
been obvious to one having ordinary skill in the art at the
time the invention was made in view of the secondary
references.

Appeal No. 2004-1043
Application No. 09/960,907

19
ii. The Beck paper is silent to a plurality of anodes
(XII.A, page 19)
Regarding claims 1-43, although Beck does not
expressly disclose providing a plurality of anodes, in the
Abstract on page 355, Beck discloses:
Operation with multiple, vertical,
monopolar, metal anodes and TiB2 plate
cathodes at 0.5 A/cm2 each side promises
a 20-fold decrease in cell volume
compared to conventional [Hall-Heroult]
cells. (Abstract, p. 355)

Thus, the Beck paper provides a strong suggestion for the
use of a plurality of anodes and a plurality of cathodes.
Additionally, the use of a plurality of anodes and a
plurality of cathodes would have been obvious to one of
ordinary skill in the art at the time the invention was
made because the use of a plurality of anodes and cathodes
increases the total surface area exposed to the
electrolyte, thus increasing the amount of aluminum that
could be produced.

iii. The Beck paper is silent to the removal of heat
from the cell using an airsweep (XII.A, page 19) and to
using a controller to control an airsweep to control the
temperature of the cell (XII.A, page 19)
The Examiner acknowledges that the Beck paper does not
expressly teach the removal of heat from the cell using an
airsweep, as recited in claims 18-34, or the use of a
controller to control the airsweep, as recited in claims
27-34. However, the Examiner deems that it would have been
obvious to one having ordinary skill in the art at the time
the invention was made to have removed heat from the cell
Appeal No. 2004-1043
Application No. 09/960,907

20
using an airsweep and a controller to control the airsweep
in view of the secondary references.

B. The Weaver Reference
i. The instant invention is patentable over the
combination of the Beck paper and the Weaver reference due
to differences in structure (XII. B, pages 2U-23)
Appellant has argued several structural differences
between the cell used in the, Beck paper and the cell
taught by Weaver, including differences in electrode
structure and heating structure.
Beck teaches a method for the electrolytic production
of aluminum from alumina. Beck teaches the structure of
the electrolytic cell, including the orientation and
structure of the anodes and cathodes, as well as the use of
an anodic liner (figs. 9-11). Like Beck, Weaver also
teaches the electrolytic production of aluminum from
alumina using anodes and cathodes.
Regarding claims 1-17, the Weaver reference also
teaches a method of advantageously using off-peak power by
intermittently operating the electrolytic cell and applying
heat to prevent the freezing of the bath when the power is
not supplied (see US ‘340, p. 3, col. 2, lines 61-74).
Therefore, one of ordinary skill in the art would have been
motivated to operate the, electrolytic cell of Beck
intermittently to take advantage of off-peak power as
taught by Weaver. One skilled in the art would have heated
the electrolyte to maintain the electrolyte in molten state
as taught by Weaver to "prevent the freezing of the bath to
a hard stone-like substance which would cause damage to the
Appeal No. 2004-1043
Application No. 09/960,907

21
interior of the cell, until such a time as the power is
again available" (see US ‘340, p. 3, col. 2, lines 61-74).
One skilled in the art would recognize that the method
disclosed by Weaver is not limited to any one structure,
insofar as the structure is capable of performing the same
method. The reference of Weaver is relied upon to teach a
method for operating an electrolytic cell intermittently
and applying heat to maintain the electrolyte in a molten
state. As seen in the Beck paper on page 359, the method
requires the application of heat to melt the electrolyte
(heat-up) and the operation of the cell at a current for a
fixed time (set periods of current flow) (see Beck, p. 359,
col. 2). Therefore, the apparatus of Beck is capable of
performing the method as taught by Weaver.
Regarding claims 18-34, Appellant has argued
structural differences between the cell of the Beck paper
and the Weaver reference in the removal of heat (see
Appellant’s Brief, p. 22).
The Examiner acknowledges that Weaver does not teach
an airsweep passing over the outside bottom of the liner.
However, Weaver does teach the removal of heat using a
cooling fluid to prevent the temperature of the bath from
rising too high (see US ‘340, p. 3, col. 2, lines 52-60).
On page 22 of Appellant’s brief, Appellant states,
"Weaver is silent with respect to an air sweep on the
bottom of the cell, and thus Applicant’s invention as set
forth in claims 1 and 10 or 18 and 27 is patentable over
this combination" (see Appellant’s Brief, p. 22, second
full paragraph). This statement is inaccurate because
claims 1 and 10 do not limit the structure of the cell to
having an air sweep on the bottom of the cell.
Appeal No. 2004-1043
Application No. 09/960,907

22
Specifically, claims 1 and 10 recite the following
limitation:
(e) maintaining said electrolyte and
aluminum in said cell in a molten
condition during said extended periods of
reduced current flow by application of
heat to said bottom for purposes of
heating said cell. (Claim 1, lines 16-18;
claim 10, lines 20-22).

Claims 1 and 10 do not recite an air sweep (or any
other specific heating means) or recite any structural
limitations regarding the placement of a heating means.
Claims 1 and 14 only limit the heating means to applying
heat to the bottom of the cell liner. As seen in Figure 2
of the Weaver reference the heating means is centrally
located within the cell. Due to mechanisms of heat
transfer, the heating means would transfer heat radially
outward from the heating means, thus heating all portions
of the electrolytic cell, including the bottom of the cell.
This is affirmed by Weaver’s disclosure that the heating
means is used to prevent the electrolyte from freezing; the
majority of the electrolyte is located below the heating
mans, implying that heat is transferred in a downward
direction towards the bottom of the cell. Additionally,
the Examiner deems claims 1 and 10, as well as 18 and 27,
obvious in view of the other secondary references, which
expressly teach advantages to providing an air sweep at the
bottom, outer surface of the cell liner.

ii. The Weaver reference teaches a different method
of agitation (XJI.B, pages 21-22)
Appeal No. 2004-1043
Application No. 09/960,907

23
On page 21, Appellant states that Weaver uses a
rotating anode to produce agitation in the bath, and
Applicant's invention does not use a hollow anode that
rotates to produce agitation. Claims 1-43 of the instant
invention requires oxygen bubbles to be generated at the
anodes and electrolyte to be stirred by the bubbles.
The Beck paper discloses, "The electrode height is the
most important factor in determining the bath circulation
rate by oxygen bubbles evolved at the anode (see Beck
paper, p. 358, beginning at second to last line in col. 1).
Since Weaver teaches the use of an indestructible anode
(see US ‘340, p.1, col. 1, line 4) as well as the
performance of the same reaction using the same electrolyte
as Beck, oxygen bubbles would also be generated in the
method of Weaver. Oxygen bubbles have a lower density than
cryolite or aluminum, and would naturally rise to the
surface, thus stirring the electrolyte. Therefore, in both
references, oxygen bubbles provide agitation to the
electrolyte.

iii. Suggestion to combine the Beck and Weaver
references (XII.B, pages 22-23)
Appellant states that there is no suggestion to modify
or combine the Beck or Weaver references because "essential
steps of Applicant's invention are missing in the
references (see Appellants Brief, p. 22, beginning in the
last paragraph).
Regarding the use of a plurality of anodes and a
plurality of cathodes recited in claims 1-43, the Beck
paper itself provides motivation for their use by stating,
"Operation with multiple, vertical, monopolar, metal anodes
Appeal No. 2004-1043
Application No. 09/960,907

24
and TiB2 plate cathodes . . . promises a 20-fold decrease in
cell volume compared to conventional [Hall-Heroult] cells"
(see p. 355, Abstract). Furthermore, one skilled in the
art would have been motivated to modify the experimental,
scaled-down cell of Beck to use a plurality of, anodes and
cathodes because the use of a plurality of anodes and
cathodes increases the available surface area, which
provides a greater area on which the reaction can take
place and increases the production of aluminum.
Regarding claims 1 and 10, Weaver discloses the steps
of periodically reducing the current flow to the cell and
applying heat to the cell during the reduced periods of
current flow to prevent the freezing of the electrolyte
(see US ‘340, p. 3, col. 2, lines fit 74). Therefore,
Weaver provides teachings and suggestions for operating the
cell intermittently and applying heat to maintain the
electrolyte in a molten condition.
Regarding the general placement of the heat in claim
claims 1 and 10 and the specific use of an air sweep in
claims 18 and 27, Weaver suggests the heating of a cell to
prevent the electrolyte from freezing, and the additional
secondary references suggests motivation for the placement
of an air sweep in relation to the cell.

C. The Berclaz Reference (XII. C, pages 23-26)
i. The use of the air sweep (XII. C, pages 23-25)
Appellant states, "Berclaz is concerned with a
different cell than that of Applicant" (page 23 of
Appellant’s Brief, beginning in the last paragraph. In
support, Appellant cites a passage of the Berclaz reference
including the phrases "to adjust the temperature of the
Appeal No. 2004-1043
Application No. 09/960,907

25
cathode and "the surface of the cathode mass 32 can be
cooled to make the electrolyte contacting it form a
protective paste (see WO ‘120, p. 26, lines 25-36).
The Examiner acknowledges that the arrangement of the
elements in the Berclaz reference is different from the
arrangement of the elements. However, Berclaz, Beck and
Weaver all teach methods of electrolytically producing
aluminum from alumina using anodes and cathodes to drive
the electrolytic reaction. In addition, Weaver teaches and
provides motivation for operating the electrolytic cell
intermittently and heating the electrolyte to prevent it
from freezing during periods when power is not applied (see
US `340, p. 3, col. 2, lines 64-74). The reference of
Berclaz is therefore relied upon for the teaching of heater
placement within the electrolytic cell. Berclaz teaches
that the temperature can be adjusted by applying a heating
or cooling gas to the space (52 located underneath the cell
liner (31) (see WO `120 Figure 6; p. 26; lines 25-36).
Furthermore, in regard to claims 18 and 27, the
passage in the Berclaz reference cited by Appellant
exemplifies the manner in which apparatuses of Berclaz,
Weaver and the instant invention operate. Each of the
apparatuses heats the electrolyte through an intervening
member. In both Berclaz and the instant invention, a heat
source (air sweep) generates heat that passes through the
cell liner. Specifically, Berclaz discloses, "[I]t is
possible to adjust the temperature of the cathode 30 . . .
by supplying a heating or cooling gas to the space 52 . . .
[and] the surface of the cathode mass 32 can be cooled to
make the electrolyte contacting it form a paste (see WO
`120, p. 26, lines 29-36). Turning the electrolyte into a
Appeal No. 2004-1043
Application No. 09/960,907

26
paste requires cooling the electrolyte, which is
accomplished by cooling the liner through the use of a
cooling gas. Therefore, Berclaz teaches controlling the
temperature of the electrolyte through the use of an air
sweep.
On page 25 of Appellant's Brief, Appellant states:
In Applicant's invention, heat is added or
removed through the metal bottom of the
cell. This is not disclosed in Berclaz.
(see page 25 of Appellant's Brief,
beginning in the first paragraph)

Berclaz teaches, “[I]t is possible to adjust the
temperature of the cathode 30 (shell 31 and cathode mass
32) by supplying a heating or cooling gas to the space 52”
(see WO ‘120, page 26, lines 29-32). The shell (31) is a
metal shell that corresponds to the metal liner of
Applicant’s invention (see WO ‘120, p. 24, lines 1-2).
Therefore, Berclaz expressly teaches adding or removing
heat through the metal bottom of the cell.

ii. Suggestion to combine Beck, Weaver and Berclaz
(XII. C, pages 25-26)
Appellant states, "[T]here is no suggestion to combine
Beck, Weaver and Berclaz, that there is no expectation of
success, and all the claim limitations have not been
disclosed in these references" (see Appellant's Brief,
p. 26, second full paragraph).
Beck teaches all of the limitations recited in claims
1, 10, 18 and 27 of the instant invention, except for the
following, a plurality of anodes (claims 1, 10, 18 and 27),
periodically reducing the current flow to the cell (claims
1 and 10), maintaining the electrolyte in a molten
Appeal No. 2004-1043
Application No. 09/960,907

27
condition during the extended periods of reduced current
flow by the application of heat to the bottom of the cell
(claims 1 and 10), removing heat from the cell through the
bottom of the liner by passing an air sweep from outside
the cell over an outer surface of the bottom of the cell
(claims 18 and 27), and using a controller to control the
air sweep (claim 27). The abstract of the Beck paper
provides motivation for using a plurality of anodes (see
Beck paper, p. 355, Abstract).
Regarding claims 1 and 10, Weaver discloses the steps
of periodically reducing the current flow to the cell and
applying heat to the cell during the reduced periods of
current flow to prevent the freezing of the electrolyte
(see US `340, p. 3, col. 2, lines 61-74). Therefore, Weaver
provides teachings and suggestions for operating the cell
intermittently and applying heat to maintain the
electrolyte in a molten condition.
Regarding claims 1, 10, 18 and 27, Berclaz teaches
adding or removing heat from the bottom of the cell using
an air sweep (see WO `120, p. 26, lines 25-36). Berclaz
also provides motivation for using an air sweep to supply
or remove heat because the air space acts as a thermic
insulating space" (see WO `120, p. 26, lines 25-29). This
teaching is consistent with both the teachings of Beck, who
discloses the use of a "firebrick insulated steel shell"
(see Beck paper, p. 359, col.1, first paragraph), and the
teachings of Weaver, who discloses that the exterior walls
are insulating (see US `340, p. 2, col.1, lines 27-39). In
each reference, the electrolytic reaction takes place at
much higher temperatures than ambient temperatures, and
insulation is desired to retain heat within the reaction
Appeal No. 2004-1043
Application No. 09/960,907

28
cell. However, as both Weaver and Berclaz suggest, cooling
is also desired to maintain the temperature of the cell.
Passing current through the cell heats the cell and can
raise the temperature to undesired levels (see US ‘340,
p. 3, col. 2, lines 53-60).
Regarding the use of a controller in claim 27, Weaver
maintains "a proper temperature control within very close
limits by using a temperature sensor and controller (page
4, col. 1, lines 1-26). The use of a temperature
controller would have been obvious to one of ordinary skill
in the art because the use of a controller allows the
temperature to be maintained at the desired operating
conditions. Beck, Weaver, and Berclaz each disclose
operating the electrolytic cell at specific operating
conditions. Since the operation of the cell itself affects
the temperature of the electrolyte, the use of a controller
would be consistent with the operation of each of the
references. Furthermore, Beck discloses the use of a
thermocouple for continuous temperature measurements (see
Beck paper, p. 359, col. 2, first paragraph.

D. No suggestion or motivation (XII. D, pages 26-27)
i. References teach away from Applicant's invention
(XII.D, pages 26-27)
Appellant states that the references teach away from
Applicant’s invention for the following reasons: the Beck
paper teaches the use of "a ‘firebrick insulated steel
shell’ which would prevent heating through the metal
bottom" (see Appellants Brief, p. 26, last paragraph;
Weaver teaches that the transfer of heat "through the
bottom is reduced to ‘substantial minimum’” (see
Appeal No. 2004-1043
Application No. 09/960,907

29
Appellant’s Brief, p. 27, first paragraph); and Berclaz
does not teach "heating under reduced electrical current
operation as in Applicant’s process" (see Appellant’s
Brief, p. 27, second paragraph).
Regarding Beck's use of a firebrick insulated steel
shell, each of the references relied upon discloses teaches
insulating the entire cell. In each of the references,
aluminum is produced at elevated temperatures (minimum of
750°C). Furthermore, Weaver and Berclaz also teach heating
and cooling the electrolyte through the use of heating
mechanisms; both references also teach that the entire cell
should be insulated. Thermal insulation is used in
electrolytic cells to maintain temperatures and to prevent
the loss of heat to the atmosphere. Berclaz expressly
teaches that an air sweep is used because the air space
"acts as an thermic insulating space" between the cell
liner and the refractory blocks that surround the apparatus
(see WO '120, p. 26, lines 25-29). Therefore, since the
Beck paper requires a heating means and an insulating shell
to insulate the apparatus, the teachings of Weaver and
Berclaz are consistent with the teachings of Beck.

E. No expectation of success (XII.E, pages 21-28)
Appellant states, "[T]he references are either silent,
teach away from, or are concerned with different processes,
there can be no reasonable expectation of success" (see
Appellant’s Brief, p. 28, first paragraph).
Beck, Weaver and Berclaz all teach methods of
electrolytically producing aluminum from alumina using
cells containing anodes and cathodes. The production of
aluminum occurs by the same process. In addition, each of
Appeal No. 2004-1043
Application No. 09/960,907

30
the references teaches the addition of heat and operating
the cell while the electrolyte is in a molten condition.
Beck discloses the addition of heat to melt the electrolyte
and then performing electrolysis (applying a current) for a
set period of time (see Beck, p. 359, col. 2). Weaver
teaches the intermittent operation of the
aluminum-producing electrolytic cell to take advantage of
off-peak power and the application of heat while power is
not supplied (see US `340, p. 3, col. 2, lines 61-74).
Therefore, Beck and Weaver both teach the application of
heat and the non-continuous application of current. Beck
and Weaver also teach the insulation of the electrolytic
apparatus to prevent the loss of heat. Berclaz teaches a
similar method of electrolytically producing aluminum from
alumina. Berclaz teaches the application of heat using an
air sweep positioned at the bottom the cell to provide heat
and also provide insulation (see WO ‘120, p. 26, lines
25-36). Since each of the references teach similar methods
and are used to perform the same process of
electrolytically producing aluminum using the application
of heat and current, one skilled in the art would
reasonably expect success in the combination of the
references.

F. Cannot provide all of the limitations of the claims
(XII.F, pages 28-29)
Appellant states, "[T]he Beck Paper, Weaver, and
Berclaz do not and cannot suggest all the limitations of
the claims because the Beck Paper is silent with respect to
periods of reduced electrical current flow to the cell and
the application of heat to the metal bottom of the cell
Appeal No. 2004-1043
Application No. 09/960,907

31
during periods of reduced current flow (see Appellant’s
Brief, p. 28, first full paragraph). Appellant further
states that "teaching or suggestion” and the “reasonable
expectation for success” must be found in the prior art.
First, Examiner acknowledges that Beck does not teach
all of the limitations of the instant claims. However, as
explained above, Weaver and Berclaz teach the limitations
that Beck is silent towards, and provide teachings and
suggestions to combine the limitations in the method of
Beck. Therefore, one of ordinary skill in the art at the
time the invention was made would have been motivated to
use the teachings of Weaver and Berclaz in the method of
Beck because Weaver and Berclaz suggest reasons to use the
modifications.

G. No suggestion to make the combination (XII.G, page
29-37)
i. Application of heat to the bottom of the cell
(XII.G, page 29)
Appellant states, “The Beck Paper and Weaver make no
mention of applying heat to the metal bottom of the cell
during periods of reduced current flow” (see Appellant’s
Brief, p. 29, first full paragraph).
Weaver discloses a heating mechanism that radiates
heat in all directions, especially the downward direction
towards the electrolyte and the bottom of the cell to
maintain the electrolyte in a molten state (see US ‘340,
fig. 2; p. 3, cot. 2, lines 61-74). Additionally, the
rejection set forth in the prior Office actions further
relied on the reference of Berclaz, which expressly teaches
Appeal No. 2004-1043
Application No. 09/960,907

32
the application of heat to the bottom of the electrolytic
cell to control the temperature (see WO ‘120, fig. 6;
p. 26, lines 25-36). Berclaz also provides motivation
for using an air sweep positioned at the bottom of the
cell (see WO `120, p. 26, lines 25-36). Therefore,
one skilled in the art would have been motivated to
provide heat to the bottom of an aluminum-producing,
electrolytic cell.

ii. Avoiding the high cost of electricity is missing
the prior art (XII.G, page 30)
Appellant states, "Applicant’s steps for operating an
electrolytic cell for producing aluminum to avoid the high
cost of electricity are missing in the prior art references
(see Appellant’s Brief, p. 30, last paragraph. Weaver
expressly teaches the intermittent operation of an
aluminum-producing electrolytic cell (see US `340, p. 3,
col. 2, lines 61-74). In addition, Weaver expressly states
that the desirable working conditions "include the use of
so-called ‘off-peak power’" (see US `340, p. 3, col. 2,
lines 61-65). Therefore, Weaver clearly provides, the
motivation for one skilled in the art to operate an
electrolytic cell intermittently to take advantage of
off-peak power.

iii. Picking and choosing parts of references (XII.G,
page 39)
Appellant states, [T]he Examiner picks and chooses
only parts of these references and ignores the fair
teachings of the references" (see Appellant’s Brief, p. 31,
last paragraph.
Appeal No. 2004-1043
Application No. 09/960,907

33
Beck, Weaver and Berclaz teach methods and apparatuses
for electrolytically producing aluminum using electrolytic
cells. Each of the references provides a source of heat to
control the temperature of the electrolyte and also the
capability to apply an electric current. One of ordinary
skill in the art recognizes that methods are capable of
being used in other apparatuses and that a rearrangement of
parts to achieve the same result is obvious. More
particularly, the references of Weaver and Berclaz provide
clear motivation for modifying the method of Beck. Beck,
Weaver and Berdaz all teach, the method of electrolytically
producing aluminum, and in each case, the apparatus of each
reference is capable of using the method of the other
because they recognize the need to supply a current to the
cell and to provide a heat source to control the
temperature of the electrolyte. Therefore, the fair
teachings of the references teach and suggest the
intermittent operation of an electrolytic cell and the
application of heat to the bottom of the cell.

iv. Beck et al. ago not provide parts missing (XII.G,
pages 33-35)
Appellant states, "Beck et al. ‘701 does not provide
parts missing in the Beck Paper, Weaver and Berclaz (see
Appellant’s Brief, p. 33, third paragraph). This statement
applies to the metallic liner.
The Beck paper teaches the use of a metallic liner
(see Beck paper, p. 359, col. 1). The reference of Beck et
al. was relied upon to disclose the desirable size of
aluminum particles used in electrolytic aluminum production
cells. Therefore, since the Beck paper teaches Appellant’s
Appeal No. 2004-1043
Application No. 09/960,907

34
"missing parts", the Beck patent is not required to supply
what is already present. One skilled in the art would
recognize that the teachings of the desired particle size
in the Beck patent are relevant to any aluminum producing
electrolytic cell regardless of the cell layout.

v. Claims 35-37 and 40-43 patentable over combination (XII.
G, page 35-37)
Appellant states, "Applicant's invention as set forth
in the claims is patentable over the Beck paper taken
singly or combined with Steiger or Berclaz" (see
Appellant’s Brief, p. 36, last paragraph. In support,
Appellant relies upon structural differences in the
references.
The Examiner acknowledges that the Beck paper is
silent with regard to applying heat to the bottom of the
metal liner, and the Beck paper further teaches the use of
an insulating material surrounding the electrolytic
apparatus. However, Berclaz teaches the use of a heating
mechanism comprising an air sweep positioned beneath the
bottom the cell liner and teaches that the air space is
also used for insulation (see WO `120, p. 26, lines 25-36).
Therefore, Berclaz clearly provides motivation for
combining the heating mechanism of Berclaz with the method
of the Beck paper because it provides both the heating
function required in the Beck paper and also provides
additional insulating function as desired in the Beck
paper. The method of Steiger is relied upon to show the
equivalence of the order in which the method steps are
performed one skilled in the art would recognize that the
teaching of method step order in Steiger is relevant to any
Appeal No. 2004-1043
Application No. 09/960,907

35
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
Appeal No. 2004-1043
Application No. 09/960,907

36
would recognize that the teachings of Steiger could be used
in any aluminum-producing electrolytic cell because only
two startup methods exist for such cells, melting before or
after addition, and Steiger teaches that they can be
equivalently used.

ii. Differences in recited method (XII.H, pages
40-41)
Regarding claim 35, Appellant states that Berclaz
differs from the Applicant’s invention because "the cathode
is cooled during operation to form a protective paste" (see
Appellant’s Brief, p. 40, last paragraph.
The formation of a protective pastels a temperature
dependant function of the electrolyte. Therefore, the
ability of the heating mechanism of Berclaz to form a
protective paste demonstrates the ability to control
temperature of the electrolyte. Thus, the heating
mechanism of Berclaz is capable of performing the function
of controlling the temperature of the electrolyte by
cooling or heating.

J. Advisory Action and Conclusion (XIII and XIV, pages
42-44)
Appellant restates positions taken previously with
regard to the differences in structure between the prior
art references. Appellant insists that the structural
differences prevent the combination of the references.
Each of the references relied discloses a method of
electrolytically producing aluminum from alumina using
anodes and cathodes. In addition, the Beck paper, Weaver
and Berclaz all suggest the application of heat to the
Appeal No. 2004-1043
Application No. 09/960,907

37
electrolyte and the application of current to perform the
electrolysis reaction. Thus, the apparatus of each of the
references is capable of performing the method claimed by
the Applicant.
Regarding claims 1-17, which require the periodic
reduction of current flow to the cell and the application
of heat to the cell to maintain the electrolyte in a molten
condition, Weaver expressly teaches that off-peak power can
be used advantageously to produce aluminum in an
electrolytic cell and that the electrolyte should be heated
to prevent the electrolyte from freezing (see US `340,
p. 3, col. 2, lines 61-74). The Beck, paper also provides
a method of producing aluminum electrolytically and
requires the addition of heat and the timed application of
current (see Beck paper, p. 359, col. 2). One skilled in
the art would have been motivated by the teachings of
Weaver that off peak power could advantageously be used in
the method of Beck by operating the cell intermittently and
preventing the freezing of the electrolyte by the
application of heat. The position of the heater is riot
relevant in claims 1-17, which only require the application
of heat to the bottom of the liner. The heating mechanism
of Weaver radiates heat in all directions, including the
bottom of the cell where the electrolyte is located (see US
`340, fig. 2). In addition, Berclaz teaches the placement
of a heating mechanism at the bottom of the cell because it
provides the advantages of insulating the cell when heating
or cooling is not required. Therefore, the different
rearrangement of components in the prior art references
show that the step of applying heat to the electrolyte is
Appeal No. 2004-1043
Application No. 09/960,907

38
capable of being performed regardless of the location of
the heating mechanism.
Regarding claims 18-43, which do require certain
structural features, specifically the use of an air sweep
positioned below the bottom surface of the metal cell
liner, the Berclaz reference expressly teaches that an air
sweep provides the ability to heat and cool, as well as
provide additional insulation when air is not passed
through the space (see WO `120, p. 26, lines 25-36). The
Beck paper requires a cell having a metal liner and
insulation surrounding the apparatus (see Beck paper, p.
359, col.1). Beck also requires the addition of heat (see
Beck paper, p. 359, col. 2). Therefore, one skilled in the
art would have been motivated to use the air sweep of
Berclaz, which is positioned below the bottom of the metal
liner, in the method of Beck because it provides heat to
the cell and also insulates the cell to prevent heat loss.
One skilled in the art would recognize that the heating
mechanism of Berclaz would be beneficial in any
electrolytic cell having a metal liner and used in a method
requiring the addition of heat. Therefore, the structural
differences between Berclaz and Beck are irrelevant.
Regarding claims 35-43, which requires the addition of
heat to the bottom of the cell liner and the placement of a
heater adjacent the cell bottom, the prior art references
teach all of the limitations of the claims. The Beck paper
describes a startup method requiring steps of adding
electrolyte to the cell tan inherent step), heating the
cell, completely melting the electrolyte, and applying a
current to generate oxygen bubbles at the anodes and
aluminum at the cathodes (see Beck paper, p. 358, col. 1,
Appeal No. 2004-1043
Application No. 09/960,907

39
beginning at last paragraph; p. 359, col. 2). The method
of Beck differs from the instant claims because Beck does
not explicitly disclose where the heater is located or the
order in which the heat is applied and the electrolyte is
added. Steiger teaches a method of electrolytically
producing aluminum and teaches that either molten
electrolyte may be added to the cell, or powdered
electrolyte may be added and then melted (see US `583,
col.13, lines 5-13). Regarding the placement of the
heater, Berclaz teaches that placement of the heater at the
bottom of the cell is advantageous because it also provides
insulation to the cell to prevent heat loss (see WO 120,
p. 26, lines 25-36). One skilled in the art would have
been motivated to combine the references Beck Berclaz and
Steiger because the teachings of the prior art suggest
advantages to the combination. One skilled in the art
would recognize that the rearrangement of the components in
each reference does not affect the Method of producing
aluminum taught by the prior art.

III. Our analysis
We incorporate the examiner’s comments as our own and
affirm each of the rejections.

IV. Conclusion
Each of the art rejections is affirmed.

Appeal No. 2004-1043
Application No. 09/960,907

40

No time period for taking any subsequent action in
connection with this appeal may be extended under 37 CFR
§ 1.136(a).

AFFRIMED

CATHERINE TIMM )
Administrative Patent Judge )
)
)
)BOARD OF PATENT
) APPEALS AND
JEFFREY T. SMITH ) INTERFERENCES
Administrative Patent Judge )
)
)
)
)
)
BEVERLY A. PAWLIKOWSKI )
Administrative Patent Judge )

BAP/sld
Appeal No. 2004-1043
Application No. 09/960,907

41
ANDREW A.EXANDER
ANDREW ALEXANDER & ASSOCIATES
3124 KIPP AVENUE
P.O. BOX 2038
LOWER BURRELL, PA 15068