Aluminum Company of America

Alcoa Inc.

Siba P Ray

Xinghua Liu

Douglas A Weirauch, Jr

Men Glenn Chu

Alfred F LaCamera

Robert K Dawless

Frankie E Phelps

Robert B Hosler

Joseph M Dynys

Robert W Woods

Robert A Rapp

Robert A DiMilia

C Norman Cochran

Robert L Kozarek

Stephen C Byrne

Kathleen M Tomaswick

Donald P Ziegler

Alfred F La Camera

Melvin H Brown

Gary P Tarcy

Mark Weaver

David H DeYoung

G Edward Graddy, Jr

Robert A Marra

John D Weyand

R Lee Troup

Donald J Bray

Jerry L Roddy

Thomas M Gavasto

William E Libent

Kirk J Malmquist

Alfred F Lacamera

Ceramic inert anodes useful for the electrolytic production of aluminum are disclosed. The inert anodes comprise oxides of Ni, Fe and Al. The Ni&#x2014;Fe&#x2014;Al oxide inert anode materials have sufficient electrical conductivity at operation temperatures of aluminum production cells, and also possess good mechanical stability. The Ni&#x2014;Fe&#x2014;Al oxide inert anodes may be used to produce commercial purity aluminum.

Stable inert anodes including an oxide of nickel, iron and aluminum

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 novel product composed of a ceramic phase particle dispersoid in metal, including uniformly distributed, finely sized carbide phase particles formed in situ in a molten metal and a novel method for producing such a ceramic phase particle dispersoid in metal are disclosed. A salt-based liquid state reaction involving a liquid metal/alloy containing a liquid Ti, B, Si, Sc, Hf, Nb, Ta, Zr, Mo, Al (when the molten metal matrix is not aluminum), or V and a halide salt containing carbon particles forms a uniform distribution of finely sized ceramic phase particles formed and dispersed in-situ in the metal matrix. The ceramic dispersoid in metal product of the present invention includes at least about 50 volume percent of a matrix metal of aluminum; and up to about 50 volume percent of a uniform distribution of finely sized ceramic phase particles formed and dispersed in-situ in the aluminum metal matrix, wherein the finely sized ceramic phase particles have an average particle diameter of less than about 2.5 microns, and wherein the uniform distribution consists of a substantially cluster-free distribution of no more than two particles attached to one another at a magnification of 500&#xd7;.

Aluminum alloy product refinement and applications of aluminum alloy product refinement

A method of making cermet inert anodes for the electrolytic production of metals such as aluminum is disclosed. The method includes the step of spray drying a slurry comprising ceramic phase particles and metal phase particles. The resultant spray dried powder, which comprises agglomerates of both the ceramic phase and metal phase particles, may then be consolidated by techniques such as pressing and sintering to produce a cermet inert anode material. The ceramic phase may comprise oxides of Ni, Fe and at least one additional metal selected from Zn, Co, Al, Li, Cu, Ti, V, Cr, Zr, Nb, Ta, W, Mo, Hf and rare earths. The metal phase may comprise Cu, Ag, Pd, Pt, Au, Rh, Ru, Ir and/or Os. The consolidated cermet inert anode material exhibits improved properties such as reduced porosity. The cermet inert anodes may be used in electrolytic reduction cells for the production of commercial purity aluminum as well as other metals.

Cermet inert anode materials and method of making same

Ceramic inert anodes useful for the electrolytic production of aluminum are disclosed. The inert anodes comprise an oxide of Ni and Fe having a controlled Ni/(Ni&plus;Fe) mole ratio which results in a single-phase structure at the operation temperatures of aluminum production cells. The Ni and Fe oxide material may also have a single-phase structure at the sintering temperature of the material. The single-phase inert anode materials maintain sufficient electrical conductivity at the operating temperatures of the cell, and also possess good mechanical stability.

Stable inert anodes including a single-phase oxide of nickel and iron

A novel method for producing a ceramic phase particle dispersoid in metal and a novel product composed thereof. The method includes (a) providing a molten composition consisting essentially of molten aluminum alloy containing molten metal selected form the group consisting of Zr, V and combinations thereof; (b) providing a chloride salt containing fine carbon particles; and (c) reacting the chloride salt containing fine carbon particles in the molten aluminum metal liquid with the molten metal liquid to form a uniform distribution of finely sized carbide particles formed and dispersed in-situ in an aluminum alloy matrix.

Metal product containing ceramic dispersoids form in-situ

A cermet inert anode for the electrolytic production of metals such as aluminum is disclosed. The inert anode comprises a ceramic phase including an oxide of Ni, Fe and M, where M is at least one metal selected from Zn, Co, Al, Li, Cu, Ti, V, Cr, Zr, Nb, Ta, W, Mo, Hf and rare earths, preferably Zn and/or Co. Preferred ceramic compositions comprise Fe O , NiO and ZnO or CoO. The cermet inert anode also comprises a metal phase such as Cu, Ag, Pd, Pt, Au, Rh, Ru, Ir and/or Os. A preferred metal phase comprises Cu and Ag. The cermet inert anodes may be used in electrolytic reduction cells for the production of commercial purity aluminum as well as other metals.

For cermet inert anode containing oxide and metal phases useful for the electrolytic production of metals

An inert anode for the electrolytic production of metals such as aluminum is disclosed. The inert anode includes a ceramic oxide material preferably made from NiO, Fe O and ZnO. The inert anode composition may comprise the following mole fractions of NiO, Fe O and ZnO: 0.2 to 0.99 NiO; 0.0001 to 0.8 Fe O ; and 0.0001 to 0.3 ZnO. The inert anode may optionally include other oxides and/or at least one metal phase, such as Cu, Ag, Pd, Pt, Au, Rh, Ru, Ir and/or Os. The Ni&mdash;Fe&mdash;Co&mdash;O ceramic material exhibits very low solubility in Hall cell baths used to produce aluminum.

Inert anode containing oxides of nickel, iron and zinc useful for the electrolytic production of metals

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

A novel product composed of a ceramic phase particle dispersoid in metal, including uniformly distributed, finely sized carbide phase particles formed in situ in a molten metal and a novel method for producing such a ceramic phase particle dispersoid in metal are disclosed. A salt-based liquid state reaction involving a liquid metal/alloy containing a liquid Ti, B, Si, Sc, Hf, Nb, Ta, Zr, Mo, Al (when the molten metal matrix is not aluminum), or V and a halide salt containing carbon particles forms a uniform distribution of finely sized ceramic phase particles formed and dispersed in-situ in the metal matrix. The ceramic dispersoid in metal product of the present invention includes at least about 50 volume percent of a matrix metal of aluminum; and up to about 50 volume percent of a uniform distribution of finely sized ceramic phase particles formed and dispersed in-situ in the aluminum metal matrix, wherein the finely sized ceramic phase particles have an average particle diameter of less than about 2.5 microns, and wherein the uniform distribution consists of a substantially cluster-free distribution of no more than two particles attached to one another at a magnification of 500&times;.

Uniformly dispersed, finely sized ceramic particles in metals and alloys

An inert anode for the electrolytic production of metals such as aluminum is disclosed. The inert anode includes a ceramic oxide material preferably made from NiO, Fe O and CoO. The inert anode composition may comprise the following mole fractions of NiO, Fe O and CoO: 0.15 to 0.99 NiO; 0.0001 to 0.85 Fe O ; and 0.0001 to 0.45 CoO. The inert anode may optionally include other oxides and/or at least one metal phase, such as Cu, Ag, Pd, Pt, Au, Rh, Ru, Ir and/or Os. The Ni&mdash;Fe&mdash;Co&mdash;O ceramic material exhibits very low solubility in Hall cell baths used to produce aluminum.

Inert anode containing oxides of nickel iron and cobalt useful for the electrolytic production of metals

A cermet composite material is made by treating at an elevated temperature a mixture comprising a compound of iron and a compound of at least one other metal, together with an alloy or mixture of copper and a noble metal. The alloy or mixture preferably comprises particles having an interior portion containing more copper than noble metal and an exterior portion containing more noble metal than copper. The noble metal is preferably silver. The cermet composite material preferably includes alloy phase portions and a ceramic phase portion. At least part of the ceramic phase portion preferably has a spinel structure.

Inert electrode containing metal oxides, copper and noble metal

A method of forming fiber reinforced aluminum phosphate bonded material having improved strength at elevated temperatures. The method comprises the steps of: (a) preparing a slurry by blending alumina and alumina phosphate solution, the slurry being substantially free of silica; (b) providing a fiber substrate; (c) infiltrating the solution into the fiber substrate; and (d) curing the infiltrated substrate to form a fiber reinforced aluminum phosphate bonded composite material. In a preferred embodiment of the present invention, the fiber substrate is made from SiC fibers.

Fiber reinforced composite having an aluminum phosphate bonded matrix

A method of producing commercial purity aluminum in an electrolytic reduction cell comprising inert anodes is disclosed. The method produces aluminum having acceptable levels of Fe, Cu and Ni impurities. The inert anodes used in the process preferably comprise a cermet material comprising ceramic oxide phase portions and metal phase portions.

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Murrysville, PA, United States of America

Siba P Ray