Electrolysis: processes – compositions used therein – and methods – Electrolytic synthesis – Utilizing fused bath
Reexamination Certificate
2002-03-01
2003-05-06
Bell, Bruce F. (Department: 1741)
Electrolysis: processes, compositions used therein, and methods
Electrolytic synthesis
Utilizing fused bath
C205S372000, C205S374000, C205S375000, C205S376000, C205S385000, C205S386000, C205S394000, C205S396000, C205S387000, C204S243100, C204S244000, C204S245000, C204S247300, C204S247400, C204S284000, C204S280000, C204S291000, C204S293000
Reexamination Certificate
active
06558525
ABSTRACT:
BACKGROUND OF THE INVENTION
The government has rights in this invention pursuant to Contract No. DE-FC07-00ID13901 awarded by the Department of Energy.
This invention relates to aluminum and more particularly it relates to an improved anode for use in the electrolytic production of aluminum from alumina dissolved in a molten salt electrolyte.
There is great interest in using an inert anode in an electrolytic cell for the production of aluminum from alumina dissolved in the molten salt electrolyte. By definition, the anode should not be reactive with the molten salt electrolyte or oxygen generated at the anode during operation. Anodes of this general type are either comprised of a cermet or metal alloy. For example, U.S. Pat. No. 4,399,008 discloses a composition suitable for fabricating into an inert electrode for use in the electrolytic production of metal from a metal compound dissolved in a molten salt. The electrode comprises at least two metal oxides combined to provide a combination metal oxide.
Also, U.S. Pat. No. 5,284,562 discloses an oxidation resistant, non-consumable anode for use in the electrolytic reduction of alumina to aluminum, which has a composition comprising copper, nickel and iron. The anode is pail of an electrolytic reduction cell comprising a vessel having an interior lined with metal which has the same composition as the anode. The electrolyte is preferably composed of a eutectic of AlF
3
and either (a) NaF or (b) primarily NaF with some of the NaF replaced by an equivalent molar amount of KF or KF and LiF.
Other anodes of this type are disclosed in U.S. Pat. Nos. 3,943,048; 3,957,600; 4,049,887; 4,529,494; 4,620,905; 4,865,701; 4,871,438; 4,956,068; 4,960,494; 4,999,097; 5,006,209; 5,069,771; 5,637,239; 5,667,649; 5,725,744; and 5,993,637.
Anodes used for electrolysis take different forms. For example, U.S. Pat. No. 3,300,396 discloses electroplating techniques and anode assemblies for electroplating wherein the anode pieces are contained in a titanium basket which is permanently destroyed in the plating tank.
U.S. Pat. No. 3,558,464 discloses novel anodes for use in electrolytic cells having generally vertical slots in the lower portion of the anodes which are open at the bottom of the anode and closed at the ends of the slots with a plurality of gas conducting channels connecting the top of the slots with the upper surface of the anode. The cathodes of the cells are the liquid mercury anode type.
U.S. Pat. No. 5,391,285 discloses an adjustable plating cell for uniform bump plating of semiconductor wafers wherein an apparatus plates metal bumps of uniform height on one surface of a semiconductor wafer (
32
). A plating tank (
12
) contains the plating solution. The plating solution is filtered (
16
) and pumped (
14
) through an inlet (
22
) to an anode plate (
24
) within plating cell (
20
). The anode plate has a solid center area to block direct in-line passage of the plating solution, and concentric rings of openings closer to its perimeter to pass the plating solution.
U.S. Pat. No. 5,532,086 discloses an anode for use in an electrochemical cell comprising a current collector layer having a thickness less than about 10 mils, and desirably less than about 4 mils, and a rigid support extending adjacent one side of the current collector layer so that the current collector layer is sandwiched between the anodic layer of the anode and the rigid support. The rigid support maintains the current collector layer in the original configuration of the current collector layer during discharge and recharge cycles of the cell. A cell containing the anode is also disclosed. The rigid support for the anode current collector can be mounted in the electrochemical cell case so as to allow for the release from the cell of gas produced at the anode.
U.S. Pat. No. 6,099,711 discloses a method for the electrolytic deposition of metal coatings, in particular of copper coatings with certain physical-mechanical and optical properties and uniform coating thickness. According to known methods using soluble anodes and applying direct current, only uneven metal distribution can be attained on complex shaped workpieces. By using a pulse current or pulse voltage method, the problem of the coatings being of varying thickness at various places on the workpiece surfaces can indeed be reduced.
U.S. Pat. No. 6,113,759 discloses an anode assembly includes a perforated anode and an electrical contact assembly attached to the anode. A perforated anode holder holds the anode. The anode holder includes perforations at least in a bottom wall such that plating solution may flow through perforations in the anode holder and perforations in the anode. An anode isolator separates the anode and a cathode. The anode isolator includes at least one curvilinear surface. The contact assembly includes a closed or substantially closed cylinder member of titanium or titanium alloy, a copper lining or disk disposed within the cylinder, and a titanium or titanium alloy post fixed and in electrical engagement with the lining or disk.
U.S. Pat. No. 6,251,251 discloses an anode assembly including a perforated anode. A perforated anode holder holds the anode. The anode holder includes perforations at least in a bottom wall such that plating solution may flow through perforations in the anode holder and perforations in the anode. An anode isolator separates the anode and a cathode. The anode isolator includes at least one curvilinear surface.
In spite of these disclosures, there is still a great need for a process utilizing a low temperature electrolytic cell for the production of aluminum using an improved anode and anode design.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an improved method for producing aluminum from alumina in an electrolytic cell.
It is another object of the invention to provide an improved method for producing aluminum from alumina in an electrolytic cell employing inert or unconsumable anodes.
It is still another object of the invention to provide an improved method for supplying alumina saturated electrolyte to the active surface of the anode in an electrolytic for producing aluminum.
And, it is another object of the invention to provide an improved method of operating an electrolytic cell employing inert anodes for producing aluminum from alumina by using an improved method of flowing alumina saturated electrolyte to anode surface.
These and other object will become apparent from the specification, claims and drawings appended hereto.
In accordance with these objects, there is provided a method of producing aluminum in an electrolytic cell containing alumina dissolved in an electrolyte, the method comprising the steps of providing a molten salt electrolyte at a temperature of less than 900° C. having alumina dissolved therein in an electrolytic cell having a liner for containing the electrolyte, the liner having a bottom and walls extending upwardly from said bottom. A plurality of non-consumable anodes and cathodes are disposed in a vertical direction in the electrolyte, the cathodes having a plate configuration and the anodes having a flat configuration to compliment the cathodes. The anodes contain apertures therethrough to permit flow of electrolyte through the apertures to provide alumina-enriched electrolyte between the anodes and the cathodes. Electrical current is passed through the anodes and through the electrolyte to the cathodes, depositing aluminum at the cathodes and producing gas at the anodes.
The invention includes an improved anode for use in an electrolytic cell for producing aluminum from alumina dissolved in a molten salt electrolyte contained in the cell. The cell contains at least one cathode and one anode disposed in the electrolyte defining a region between the electrodes, the cathode having a flat surface. The improved anode comprises a substantially flat surface configuration for disposing opposite said cathode surface to provide an anode-cathode distance defining a region between said anode and said cathode surfaces. Th
Barnett Robert J.
Bradford Donald R.
Mezner Michael B.
Alexander Andrew
Bell Bruce F.
Northwest Aluminum Technologies
LandOfFree
Anode for use in aluminum producing electrolytic cell does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Anode for use in aluminum producing electrolytic cell, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Anode for use in aluminum producing electrolytic cell will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3043085