Metallurgical, Inc.

Gary V Upperman

James C Withers

A process for the electrolytic deposition of aluminum at low temperatures and low electrical potential in which the anode is the sole source of aluminum and comprises a composite mixture of an aluminous material such as aluminum oxide and a reducing agent. The composite anode is positioned in the electrolyte with at least one active surface of the anode in opposed relationship to but spaced from the surface of the cathode. The greatly increased electrical resistance of the mixture of aluminum oxide and the reducing agent is minimized by passing the anodic current through one or more conductors of low electrical resistivity which extend through the mixture to or approximately to the active reaction face of the mixture in the electrolyte. The position of the ends of said conductors is maintained relative to the reaction face as the mixture is consumed in the electrolysis. These arrangements provide a minimal length of current path through the high resistant mixture and thus result in a low voltage drop of anodic current in its passage to the reaction face. A bipolar electrode arrangement may be employed with the mixture of aluminum oxide and reducing agent covering one face of the electrode with the opposite face of the electrode providing a cathode surface.

Process for the electrolytic deposition of aluminum using a composite

Carbon containing electrodes are made with a considerable reduction of energy over conventional methods for use in the aluminum industry and the like that have the strength, density and control of dimensional shape necessary for an electrode withstanding the considerable thermal, electromagnetic and chemical forces encountered in the electrolytic production of metals such as aluminum. Thus, the manufacturing process forms the green electrode materials of carbon powder or a carbon-alumina, etc. mixture and mixed with a binder comprising a liquid thermo-setting resin which is pre-cured under pressure to form a hardened stable electrode form that does not droop during coking or require support. Savings of energy here results by eliminating a heat cure step and in a reduced coking volume and time for such electrodes. Preferably the coking takes place in a tunnel kiln to further reduce energy by heating substantially only the electrodes. Coking times for such electrodes are further significantly reduced from the usual 2 days coking cycle with several days of controlled warmup getting the furnace to the maximum temperature and may be only a few hours particularly when indented slots or holes are provided in the green electrodes to minimize path lengths for escape of volatiles during coking. This permits a much faster warmup cycle and a much shorter overall coking period to save additional significant amounts of energy. Thus both faster heating rates to achieve maximum coking temperatures and shortened coking times required at peak heats are afforded by this invention. Further energy saving improvement is afforded by use of metallic or graphite heat conductors positioned in the holes or slots during coking.

Energy reduction in the manufacture of pre-baked carbon containing

A cell for the electrolysis of magnesium at low temperatures and electrical potential using a composite anode consisting of a mixture of an oxygen containing compound of magnesium and a reducing agent with internal conductors extending through the composite mixture to provide low resistance current paths through the highly resistive mixture to the active anode surface. The mixture may be employed in a self-baking mode or be prebaked. Alternatively, the mixture may be in particulate form contained within a porous membrane. A bipolar arrangement may also be employed.

Cell with composite anode for electrolytic production of magnesium

An anode is provided for use in the electrolytic deposition of aluminum at low temperatures in which the anode is the sole source of aluminum and comprises a composite mixture of an aluminous material such as aluminum oxide and a reducing agent such as carbon. Conductor means of higher electrical conductivity than the anodic mixture are provided to conduct substantially the entire anodic current to the active anode surface thereby reducing the voltage drop through the highly resistive composite mixture. The conductors may be of aluminum and sized to melt back at substantially the same rate at which the mixture is consumed. The mixture may be employed in a self-baking mode or be pre-baked. Alternatively, the mixture may be in a particulate form and contained within a porous membrane which passes the electrolyte or other dissolved material while withholding undissolved impurities. The membrane may be used with a conductor to provide bipolar electrode faces.

Composite anode for the electrolytic deposition of aluminum

A cell for the electrolytic deposition of aluminum at low temperatures and low electrical potential in which the anode is the sole source of aluminum and comprises a composite mixture of an aluminous material such as aluminum oxide and a reducing agent. Conductor means of higher electrical conductivity than the mixture are provided to conduct substantially the entire anodic current to the active anode surface thereby reducing the voltage drop through the highly resistive composite mixture. The mixture may be employed in a self-baking mode or be prebaked. Alternatively, the mixture may be in a particulate form and contained within a porous membrane which passes the electrolyte or other dissolved material while withholding undissolved impurities. The cell may have bipolar electrodes and may be used in combined winning and refining configurations.

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North Olmsted, OH, United States of America

Gary V Upperman