Anode for use in aluminum producing electrolytic cell

Abstract

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 Cu—Ni—Fe—Sn 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.

Description

BACKGROUND OF THE INVENTION[0001]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.[0002]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 disclosed in U.S. Pat. Nos. 4,592,812; 4,865,701; 5,006,209; 5,284,562; 6,558,525; 6,723,222; 6,800,191; 6,811,676 and 6,837,982. Examples of other such anodes of this type are comprised of a cermet. 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...

AI Technical Summary

Benefits of technology

[0020]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 is comprised of a Cu—Ni—Fe—Sn alloy which can operate on reduced voltage resulting from reduced resistance of the surface oxide layer. The anode has long term stability of the surface oxide layer and thus produces excellent purity aluminum. It has a substantially flat surface configuration for disposing opposite the cathode surface to provide an anode-cathode distance defining a region between said anode and said cathode surfaces. When apertures are used in the anode, it permits flow of electrolyte through the apertures to provide alumina-enriched electrolyte in the region between the anodes and the cathodes.

[0024]Thus, an anode which is comprised of a Cu—Ni—Fe—Sn alloy is provided 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, the cathode having a planar surface. The anode has a substantially flat first surface for disposing opposite the cathode planar surface to provide a controlled anode-cathode distance defining a region between the anode and the cathode surfaces. The anode has a second surface disposed opposite the first surface to provide the anode with a thickness dimension. Apertures can extend from the first surface of the anode to the second surface, the apertures defined by a wall of the anode, the wall can provide additional anode active surface area during electrolysis of the alumina in the cell.

Problems solved by technology

According to known methods using soluble anodes and applying direct current, only uneven metal distribution can be attained on complex shaped workpieces.

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