Aluminum Company of America

Perry A Foster, Jr

Subodh K Das

Stanley C Jacobs

Gregory J Hildeman

Gary P Tarcy

C Norman Cochran

Aaron J Becker

Warren E Haupin

Richard W Peterson

William C Sleppy

John R Minick

Raymond D Wiltzius

A method for making a light metal-rare earth metal alloy comprises adding a pellet to a bath of molten light metal, said pellet consisting essentially of a mixture of light metal powder and rare earth metal-containing compound. Such pellets, which are made under pressures of about 9 ksi or more, are preferably added to molten baths of aluminum, magnesium or combinations thereof. The light metal powders and rare earth metal-containing compounds that are mixed together to form said pellets are preferably substantially similar in terms of median particle size. This method is suitable for aluminothermically reducing scandium oxide to make aluminum-scandium alloy therefrom.

Method for making a light metal-rare earth metal alloy

An electrolysis method involving electrolyzing, between anodic and cathodic surface areas, a compound dissolved in a solvent. A liquid cathodic body is located in a region such that it is possible for waves in the body to touch anodic surface area. The improvement includes placing a bed of objects into the mentioned region. Interstices remain between the objects for accommodating liquid from the mentioned body.

Electrolysis method

An improved electrolytic cell is provided for production of a metal such as aluminum by electrolysis of a compound of the metal in a solvent or bath such as molten salt. Electrolysis is carried out by passing a current from an anode to a cathode between which the solvent bath is situated. The cathode comprises a base cathode and cathode extension surfaces comprising graphite and at least 90% refractory hard metal such as titanium diboride. The cathode extension surfaces are produced from a mixture comprising at least 90% refractory hard metal and a carbonaceous binder with little or substantially no particulate carbonaceous material and graphitizing said mixture above 2350.degree. C. to graphitize the carbonaceous material therein to exhibit the graphitic structure.

Composite cathode

A cathode for an electrolytic cell operated at elevated temperature, the cathode comprising a refractory hard metal (RHM) body embedded in a carbonaceous base. The cathode is provided with an intermediate layer of fibrous material between a side wall of a seat in the base and a wall segment of the RHM body. The layer preferably comprises low-density carbon felt, and the layer prevents breakage of the RHM body by providing a cushion against differential thermal expansion and contraction of the base and body, especially during cell start-up.

Intermediate layer for seating RHM tubes in cathode blocks

A metal such as aluminum is produced by electrolysis of a compound of the metal in a solvent or bath such as molten salt. Electrolysis is carried out by passing a current from an anode to a cathode between which the solvent bath is situated. The cathode is composed of a composite comprising graphite and a refractory hard metal such as titanium diboride. The properties and performance of the composite cathode are improved through careful manufacturing controls and selectivity with respect to electrode configuration and cell operating conditions.

Electrolytic production of aluminum using a composite cathode

A metal such as aluminum is produced by electrolysis of a compound of the metal in a solvent such as a molten salt. Electrolysis is carried out by passing a current from an anode to a cathode between which the solvent bath is situated. The cathode or cathode member is composed of a graphite substrate coated with a refractory hard metal such as titanium diboride. The coating adhesion of the TiB.sub.2 is improved through control of the manufacture and structure of the graphite substrate to favor a higher coefficient of thermal expansion and to have the density of the graphite fall within a range of 1.6 to 1.85 grams per cubic centimeter. The steps in producing the graphite may include working it so as to provide a grain direction. One embodiment includes aligning the refractory hard metal coated graphite in the electrolytic cell with the graphite grain direction parallel to the direction of current flow from anode to cathode. The refractory hard metal coating can be imparted by chemical vapor deposition and should exhibit a dense columnar structure which reduces penetration of the coating by molten aluminum.

Method of producing aluminum using graphite cathode coated with

A method for the electrolytic production of metal, including electrolyzing, between anodic and cathodic surface areas, a compound of the metal dissolved in a molten solvent, the electrolyzing being performed at a temperature such that the metal is formed in the molten state, the metal collecting in a molten metal pad, wherein the improvement includes the provision of cathodic surface area in the form of an array of elements like islands protruding out of the pad into the solvent toward the anodic surface area for establishing a series of locations at which the anode-cathode distance is up to 11/4 inches. A method for the electrolytic production of metal, including electrolyzing, between anodic and cathodic surface areas, a compound of the metal dissolved in a molten solvent, the electrolyzing being performed at a temperature such that the metal is formed in the molten state, wherein the improvement includes the provision of cathodic surface area formed from at least one hollow body in the solvent, the hollow body containing molten material. A method for the electrolytic production of metal, including electrolyzing, between anodic and cathodic surface areas, a compound of the metal dissolved in a molten solvent, the electrolyzing being performed at a temperature such that the metal is formed in the molten state, wherein the improvement includes the provision of cathodic surface area in the form of a grate inserted in the solvent.

Electrolytic production of metal

A method for the electrolytic production of metal, including electrolyzing, between anodic and cathodic surface areas, a compound of the metal dissolved in a molten solvent, the electrolyzing being performed at a temperature such that the metal is formed in the molten state, the metal collecting in a molten metal pad, wherein the improvement includes the provision of cathodic surface area in the form of an array of elements protruding out of the pad into the solvent toward the anodic surface area for establishing a series of locations at which the anode-cathode distance is up to 11/4 inches. A method for the electrolytic production of metal, including electrolyzing, between anodic and cathodic surface areas, a compound of the metal dissolved in a molten solvent, the electrolyzing being performed at a temperature such that the metal is formed in the molten state, wherein the improvement includes the provision of cathodic surface area formed from at least one hollow body in the solvent, the hollow body containing molten material. A method for the electrolytic production of metal, including electrolyzing, between anodic and cathodic surface areas, a compound of the metal dissolved in a molten solvent, the electrolyzing being performed at a temperature such that the metal is formed in the molten state, wherein the improvement includes the provision of cathodic surface area in the form of a grate inserted in the solvent.

A process for producing aluminum in which alumina is decomposed electrolytically to aluminum metal in an electrolyte bath between an anode and a cathodic interface formed between aluminum metal and the electrolyte bath. The bath consists essentially of Al.sub.2 O.sub.3, NaF, and AlF.sub.3, and has a weight ratio NaF to AlF.sub.3 up to 1.1:1. During decomposition, the bath is maintained at an operating temperature greater than 40.degree.C above the cryolite liquidus temperature of the bath and effective for preventing bath crusting in interfacial areas between bath and aluminum metal.

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New Kensington, PA, United States of America

Perry A Foster, Jr