Aluminum Company of America

Alcoa Inc.

Alfred F LaCamera

Siba P Ray

Xinghua Liu

Robert K Dawless

Frankie E Phelps

Robert A DiMilia

Douglas A Weirauch, Jr

Jan H Van Linden

Robert B Hosler

Robert L Kozarek

Joseph M Dynys

Thomas V Pierce

James O Parkhill

James T Burg

Mark Weaver

Leroy E D'Astolfo

Stanley C Jacobs

Donald L Kinosz

John M Urbanic

Thomas R Hornack

Robert William Graham

Kathleen M Tomaswick

LeRoy E Dastolfo, Jr

Matthew J McMonigle

Thomas L Francis

Donald L Stewart

R Lee Troup

Chester H Klingensmith

Charles J Culleiton

Jerry L Roddy

Thomas J Robare

Wayne W Hyland

Henry G Wickes, Jr

Kirk J Malmquist

Thomas A Trzeciak

Robert F Robl, Jr

A method for protecting anode assemblies in an electrolytic cell from thermal shock is disclosed. The method generally involves applying a thermal insulating layer () to the anode () prior to preheating the anode assembly in a furnace, where the layer () protects the anode () from thermal shock during transfer from the preheat furnace to the electrolytic cell. In a preferred embodiment the anode () is attached to a castable plate () that is also protected from thermal shock by an insulating layer.

Protecting an inert anode from thermal shock

An inert anodefor use in an electrolytic cellfor producing metals such as aluminum, is made by providing chemical source materialssuch as at least two of metal salts, metal particles, or metal oxides and dissolving them to form a solution or a slurryfollowed by adding a baseand adjusting the pH so that a gelis formed which is dried and calcinedto provide a blend of metal oxide powderwhich can be pressed and sinteredto form an inert anode

Synthesis of multi-element oxides useful for inert anode applications

Methods and apparatus are disclosed for reducing sulfur impurities in aluminum electrolytic production cells in order to significantly increase current efficiency of the cells. An impurity reduction zone may be created in the bath of an inert anode cell by submerging a purifying electrode in the bath. In another embodiment, an oxygen barrier tube may be disposed in a portion of the bath. In a further embodiment, reductants such as aluminum, CO and/or COare added to the bath. In another embodiment, electrode current is interrupted or electrodes are removed from selected regions of the cell in order to allow gaseous impurities to escape from the bath. Sulfur impurity levels may also be reduced in inert anode cells by scrubbing bath emissions from the cell before they are reintroduced into the cell, and by controlling sulfur impurity contents of materials added to the cell.

Methods and apparatus for reducing sulfur impurities and improving current efficiencies of inert anode aluminum production cells

A process for producing aluminum metal by carbothermic reduction of alumina ore. Alumina ore is heated in the presence of carbon at an elevated temperature to produce an aluminum metal body contaminated with about 10-30% by wt. aluminum carbide. Aluminum metal or aluminum alloy scrap then is added to bring the temperature to about 900-1000&deg; C. and precipitate out aluminum carbide. The precipitated aluminum carbide is filtered, decanted, or fluxed with salt to form a molten body having reduced aluminum carbide content.

Carbothermic aluminum production using scrap aluminum as a coolant

A method of producing commercial purity aluminum in an electrolytic reduction cell comprising ceramic inert anodes is disclosed. The method produces aluminum having acceptable levels of Fe, Cu and Ni impurities. The ceramic inert anodes used in the process may comprise oxides containing Fe and Ni, as well as other oxides, metals and/or dopants.

Electrolytic production of high purity aluminum using ceramic inert anodes

An electrolytic cell and electrolytic process for producing a metal by reduction of a metal oxide dissolved in a molten salt bath containing at least one chloride and at least one fluoride. A solid conductor of oxide ions is interposed between the anode and the cathode. The solid conductor preferably comprises zirconia, stabilized in cubic form by addition of a divalent or trivalent metal oxide such as yttria.

Electrolysis in a cell having a solid oxide ion conductor

Aluminum is produced by electrolytic reduction of alumina in a cell having a cathode, an inert anode and a molten salt bath containing metal fluorides and alumina. The inert anode preferably contains copper, silver and oxides of iron and nickel. Reducing the molten salt bath temperature to about 900-950.degree. C. lowers corrosion on the inert anode constituents.

Reduced temperature aluminum production in an electrolytic cell having

An electrolytic cell for reduction of a metal oxide to a metal and oxygen has an inert anode and an upwardly angled roof covering the inert mode. The angled roof diverts oxygen bubbles into an upcomer channel, thereby agitating a molten salt bath in the upcomer channel and improving dissolution of a metal oxide in the molten salt bath. The molten salt bath has a lower velocity adjacent the inert anode in order to minimize corrosion by substances in the bath. A particularly preferred cell produces aluminum by electrolysis of alumina in a molten salt bath containing aluminum fluoride and sodium fluoride.

Molten salt bath circulation design for an electrolytic cell

A low temperature salt bath for the electrolysis of metal oxides to produce the corresponding metal. The bath comprises a first salt, comprised of at least one fluoride salt, and a second salt, comprised of at least one chloride salt. The fluoride salt increases the metal oxide solubility in the molten salt bath, and the chloride salt reduces the bath liquidus temperature of the salt bath. The preferred process of practicing the invention includes using an anode consisting essentially of carbonaceous material and having an effective surface area about equal to the projected surface area of the anode.

Process for low temperature electrolysis of metals in a chloride salt

Salt-based melting process

Electrolytic cell and process for metal reduction

A container body for foods and beverages having reduced gas and vapor permeability. The container body is preferably formed from a plastic resin and coated with a thin film of diamond-like carbon.

Container body having improved gas barrier properties

A process for decomposing chlorinated hydrocarbon compounds wherein the compounds are heated to an elevated temperature of about 800.degree. to 1200.degree. C. and reacted with alumina and a reactive carbon source. A preferred operating temperature is about 800.degree. to 900.degree. C. and preferred carbon sources are activated carbon and coked alumina. The process is particularly useful for disposing of chlorinated organic compounds that are generated in the production of metal chlorides by chlorination of a metal oxide in the presence of carbon.

Process for decomposing chlorinated hydrocarbon compounds

A process for producing a refractory material comprising essentially beta'-SiAlON wherein the initial reactants include discrete particles of an SiO.sub.2 source and discrete particles of an Al.sub.2 O.sub.3 source.

Process for producing beta'-silicon aluminum oxynitride (B'-SiAlON)

An improved process for the electrolytic production of aluminum by electrolysis of aluminum chloride in a molten salt electrolyte bath. The improved process is characterized by a reduction in solubility of the reduced aluminum metal as well as a smaller metal droplet size permitting closer anode-cathode spacing in the electrolysis cell and a lower electrical resistance. The improvement comprises performing the electrolysis in an electrolyte consisting essentially of from 0.5 to 15 wt. % aluminum chloride, from 0.5 to 40 wt. % of one or more alkaline earth metal chlorides selected from the class consisting of magnesium chloride, barium chloride, strontium chloride and calcium chloride, from 10 to 90 wt. % lithium chloride and the balance sodium chloride.

Molten salt bath for electrolytic production of aluminum

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Trafford, PA, United States of America

Alfred F LaCamera