Norskhydro Asa

Stein Julsrud

Ole-Jacob Siljan

Bent Erlend Vigeland

Turid Risdal

Odd-Arne Lorentsen

Knut Ingvar &angst;sen

Knut Ingvar Åsen

Christian Rosenkilde

Turid Breivik

Rita Glenne

Tyke Naas

The present invention relates to methods for operating and controlling the temperature of inert electrodes during production of molten aluminum by electrolysis of an aluminous ore, preferably alumina, dissolved in molten salts, preferably a fluoride based electrolyte, in an electrolysis cell with vertical or essentially vertical electrode configuration. The invention describes methods of designing and operating inert electrodes in a vertical and/or inclined position for production of aluminum metal, where said electrodes have an operating temperature that may deviate from the electrolyte temperature, thereby controlling the dissolution of electrode materials and preventing solid deposit formation on the electrodes. The present invention is also applicable to aluminum production cells utilizing inert electrodes in a horizontal configuration, and traditional Hall-H&#xe8;roult cells retrofitted with inert anodes.

Control of temperature and operation of inert electrodes during production of aluminum metal

The present invention relates to a method of improving the current efficiency (CE) in an electrolytic aluminum production cell with an electrolytic bath, at least one anode and at least one cathode, and passing current between said anode and said cathode through said bath and feeding an aluminum containing feedstock to the cell. The CE is improved in that the aluminum containing feedstock is prepared in a manner where it contains substantially no humidity or water before it is fed to the cell, where the electrolytic process is carried out at conditions with reduced amount of hydrogen present.

Method and means for improving electrolysis cell operation

A method for electrolytic production of aluminium metal from an electrolytic () including aluminium oxide, by performing electrolysis, with at least one inert anode () and at least one cathode () thus forming part of an electorwinning cell. The anode evolves oxygen gas and the cathode has aluminium discharged onto it in the electrolysis process, where the oxygen gas enforces an electrolyte flow pattern. The oxygen gas is directed to flow into anode grooves and is drained away from the interpolar room, thereby establishing an electrolyte flow pattern between the electrodes () and () and between over the anodes (). The invention also concerns and anode assembly and an electrowinning cell.

Utilisation of oxygen evolving anode for Hall-H&#xe8;roult cells and design thereof

An anode for the electrolysis of aluminium made from an outer dense layer of a ceramic material on a dense core made from a composite of the ceramic material of the outer layer and an electronic conductor.

Dimensionally stable anode for the electrowinning of aluminum

A method for operating one or more electrolysis cells () for production of aluminium, the cell comprising inert or substantially inert anodes, where an oxygen containing gas () evolved by the electrolysis process in the cell is gathered and removed therefrom. The oxygen containing gas is introduced into a combustion chamber () where it is reacted with a carbon containing gas () in a combustion process. Emisions of COand NOcan be reduced.

Method for operating one or more electrolysiscells for production of aluminium

The present invention relates to a solid multicomponent mixed proton and electron conducting membrane for use in a reactor, where the membrane comprises a mixed metal oxide having a structure represented by the formula: AA'(BB&#x2032;)O, wherein A is a lanthanide element or mixtures thereof, A&#x2032; is an alkaline earth element or mixtures thereof, B is chromium, manganese, or iron, B&#x2032; is titanium, aluminum, zirconium, or hafnium, and x, y, w, and d each represent a number such that 0&#x2266;x&#x2266;1, 0&#x2266;y&#x2266;1, 0.9&#x3c;w&#x3c;1.1, and d equals a number that renders the compound charge neutral and is not less than zero and not greater than about 0.6.

Solid multicomponent mixed proton and electron conducting membrane

The present invention relates to a method for production of molten aluminium by electrolysis of an aluminous ore, preferably alumina, in a molten salt mixture, preferably a sodium fluoride&#x2014;aluminium fluoride-based electrolyte. The invention describes an electrolysis cell for said production of aluminium by use of essentially inert electrodes in a vertical an/or inclined position, where said cell design facilitates separation of aluminium and evolved oxygen gas by providing a gas separation chamber () arranged in communication with the electrolysis chamber (), thus establishing an electrolyte flow between the electrolysis chamber () and the gas separation chamber ().

Method and an electrowinning cell for production of metal

A material suitable for use as the active anode surface in the electrolytic reduction of alumina to aluminium metal defined by the formula: ABCOwhere A is a divalent cation or a mixture of cations with a relative preference for octahedral coordination, B is a trivalent cation or mixture of cations with a relative preference for tetrahedral coordination, C is a trivalent cations with a relative preference for octahedral coordination or a four-valent cation with a relative preference for octahedral coordination, O is the element oxygen: When C is trivalent x=0, 0.8&#x3c;d&#x3c;1, &#x3b4;&#x3c;0.2 and x+d+d is essentially equal to 1. When C is four-valent 0.4&#x3c;x&#x3c;0.6, 0.4&#x3c;d&#x3c;0.6, &#x3b4;&#x3c;0.2 and x+d+&#x3b4; is essentially equal to 1.

Material for a dimensionally stable anode for the electrowinning of aluminum

The present invention relates to a solid multicomponent membrane for use in a reactor where the membrane comprises a mixed metal oxide having a structure represented by the formula: La Ca (Fe Ti Al ) O wherein x, y, y&prime;, w, and d each represent a number such that 0.1&lE;(y&plus;y&prime;)&lE;0.8, 0.15&lE;(x&plus;y&prime;) &lE;0.95, 0.05&lE;(x&minus;y)&lE;0.3, 0.95<w<1, and d equals a number that renders the compound charge neutral and is not less than zero and not greater than about 0.8. Furthermore, the present invention relates to a use of the membrane in a reactor for generating heat or for generating synthesis gas.

Membrane and use thereof

The present invention relates to a dense single-phase membrane having both high ionic and electronic conductivity and capable of separating oxygen from an oxygen containing gaseous mixture, where the membrane comprises a mixed metal oxide material with interstitial oxygen excess represented by the formula A A&prime; A&Prime; B B&prime; B&Prime; B&prime;&Prime; O , where A, A&prime; and A&Prime; are chosen from group 1, 2 and 3 and the lanthanides; and B, B&prime;, B&Prime; and B&prime;&Prime; are chosen from the transition metals according to the periodic table of the elements adopted by IUPAC wherein 0&lE;y&lE;2, 0&lE;y&prime;&lE;2, 0&lE;y&Prime;&lE;2, 0&lE;x&lE;1, 0&lE;x&prime;&lE;1, 0&lE;x&Prime;&lE;1, 0&lE;x&prime;&Prime;&lE;1, and x and y each represents a number such that y&plus;y&prime;&plus;y&Prime;&equals;2, x&plus;x&prime;&plus;x&Prime;&plus;x&prime;&Prime;&equals;1, and &dgr; is a number where 0&lE;&dgr;<1 quantifying the oxygen excess. Furthermore, the invention relates to a use of the membrane for production of pure oxygen, oxygen enrichment of a sweep gas for fossil energy conversion, for synthesis gas production and for production of oxygen for application in any catalytic or non-catalytic processes wherein oxygen is one of the reactants.

A method is provided for performing catalytic or non-catalytic processes which uses oxygen supplied from the permeate side of a mixed oxygen ion and electron conducting membrane by means of a sweep gas at an elevated temperature. The sweep gas is formed by burning fuel in a sweep gas preheater. The sweep gas containing oxygen picked up from the membrane is reacted with a hydrocarbon fuel in a catalytic reactor to form a syngas containing nitrogen and hydrogen. The nitrogen and hydrogen containing syngas is worked up into ammonia; the ammonia is burned in an ammonia burner to produce a nitrogen oxides containing gas, and the nitrogen oxides containing gas is used in the production of nitric acid. The process is able to directly transfer the oxygen containing sweep gas to the catalytic reactor, without any intermediate cooling; recompression and reheating.

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Skien, Norway

Stein Julsrud