Patents Assigned to Elkem ASA
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Patent number: 6572262Abstract: A method of densifying a bulk particulate material includes at least partially confining the bulk particulate material, and rotating a rotatable member submerged under the bulk particulate material about an axis of rotation to cause movement of the material particles essentially towards or away from the axis or rotation, thereby to provide a densified bulk particulate material. The method is particularly suitable for densifying silica fume. The invention extends to apparatus for densifying a bulk particulate material.Type: GrantFiled: April 2, 2001Date of Patent: June 3, 2003Assignee: Elkem AsaInventor: Kevan Vaughan Russel-Smith
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Patent number: 6530970Abstract: A method for aluminum recovery during the carbothermic production of aluminum in a smelting furnace (1,2) is disclosed, where during carbothermic reduction of alumina, aluminum and aluminum suboxide vapors are produced (3, 4), which are reacting with carbon. Reactive carbon is generated in situ by the cracking of hydrocarbon compounds (6) in a separate closed reactor vessel (5) at a temperature greater than about 1955° C. Solid aluminum carbide that formed during the reaction can then be recycled by a conduit (8) to the primary reactor for reduction to aluminum, and reactor gas (10) can be fed to a cooler (9).Type: GrantFiled: May 21, 2001Date of Patent: March 11, 2003Assignees: Alcoa Inc., Elkem ASAInventor: Tor Lindstad
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Patent number: 6478840Abstract: The present invention relates to a method for reduction of chromium content in slag during melting of stainless steel in electric arc furnaces where steel scrap and additive alloys are melted in an electric steel furnace, whereafter molten steel and slag are tapped into a ladle, removal of the slag from the steel in the ladle, transferring of the molten steel from the ladle to a converter wherein the steel is refined and where the chemical composition of the steel is adjusted by addition of alloying elements. According to the invention fine particulate ferrosilicon is added to the slag during the time interval between the slag and the steel are melted, but before the molten steel and slag is tapped into the ladle.Type: GrantFiled: June 4, 2001Date of Patent: November 12, 2002Assignee: Elkem ASAInventors: Ole Svein Klevan, Jacob Sandberg
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Patent number: 6330270Abstract: The present invention relates to a method for weighing an electrode submerged in the charge of an electric smelting furnace. The electrode is moved in vertical direction at least once, whereafter the electrode is lifted and the weight of the electrode is registered shortly after the electrode has been lifted.Type: GrantFiled: September 19, 2000Date of Patent: December 11, 2001Assignee: Elkem ASAInventors: Georg Brustad, Frode Haugen, Halvard Tveit, Aasgeir Valderhaug
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Patent number: 6178191Abstract: The present invention relates to a method for determination of the electrode tip position for consumable electrodes in electric smelting furnaces, which electrodes being submerged in the furnace charge. The voltage between two geometrically displaced points on the outside of the steel wall of the furnace pot is measured during operation of the furnace, points being situated as close as possible to the electrode for which the electrode tip position is to be determined, and as far away as possible from the other electrodes in the furnace. The electrode current for the electrode for which the electrode tip position is to be determined, is recorded at the same time as the voltage between the two points are measured, whereafter the difference between measured voltage between the two points and measured electrode current is calculated, and where the absolute value of difference increases when the electrode tip position increases and decreases when the absolute value of difference decreases.Type: GrantFiled: November 15, 1999Date of Patent: January 23, 2001Assignee: Elkem ASAInventors: Kjell Kalgraf, Gunnar Morkesdal, Ragnar Tronstad
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Patent number: 6177045Abstract: A composition for inoculating grey iron, particularly low sulphur grey iron, comprises by weight: rare earth 1.0-4.0%, preferably 1.5-2.5%; strontium 0.5-1.5%, preferably 0.7-1.0%; calcium 1.5% maximum, preferably 0.5% maximum; aluminum 2.0% maximum, preferably 0.5% maximum; silicon 40.0-80.0%, preferably 70.0-75.0%; iron balance. The composition is most preferably free of calcium and aluminum. The rare earth may be cerium, mischmetall or a mixture of cerium and other rare earths. The composition may be a mixture of ferrosilicon and the other constituents, a ferrosilicon alloy containing the other constituents or a rare earth and a silicon-bearing inoculant containing strontium.Type: GrantFiled: August 29, 1998Date of Patent: January 23, 2001Assignee: Elkem ASAInventors: Christopher Ecob, Douglas White, David Butler
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Patent number: 6157667Abstract: An electric furnace and method thereof for electric calcining of carbonaceous material for the production of graphite or graphite-containing material, wherein the carbonaceous material is supplied to the top of a vertically arranged furnace having a cylindrical cross section. The furnace is equipped with one top electrode and one bottom electrode supplied with electric current for heating of the carbonaceous material. The calcined carbonaceous material is discharged at the bottom of the furnace in one stream in the center of the furnace and one stream near the periphery of the furnace.Type: GrantFiled: October 5, 1999Date of Patent: December 5, 2000Assignee: Elkem ASAInventors: Johan Johansen, Arnfinn Vatland
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Patent number: 6102983Abstract: The invention relates to an inoculant for the manufacture of cast iron with lamellar, compacted or spheroidal graphite. The inoculant comprises between 40 and 80% by weight of silicon, between 0.5 and 10% by weight of calcium and/or strontium and/or barium, between 0 and 10% by weight of cerium and/or lanthanum, between 0 and 5% by weight of magnesium, less than 5% by weight of aluminium, between 0 and 10% by weight of manganese and/or titanium and/or zirconium, between 0.5 and 10% by weight of oxygen in the form of one or more metal oxides, the balance being iron, said inoculant further comprising between 0,1 and 10% by weight of sulphur in the form of one or more metal sulphides. The invention further relates to a method for the production of the inoculant.Type: GrantFiled: June 16, 1998Date of Patent: August 15, 2000Assignee: Elkem ASAInventor: Torbj.o slashed.rn Skaland
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Patent number: 5993508Abstract: Silicon-containing residues, as they accumulate especially during the synthesis of organosilanes out of metallic silicon, and especially methyl chloride, are processed according to the invention to briquettes, being additives for the quality adjustment of cast iron being produced in a cupola furnace in order to avoid either costly regeneration for the recovering of the valuable components or the total dumping of said silicon-containing residues. Besides the silicon-containing residue the briquettes contain 1-10 percent by weight of cardboard fiber, 5-40 percent by weight of hydraulic cement and 0-20 percent by weight of additional additives having influence on the quality of the cast iron. The cement- and cardboard fiber-containing briquettes are mechanically and thermally sufficiently stable with respect to the operation of the melting furnace. The yielding rate of the inserted small-sized silicon in the cast iron is about 85% and reaches thereby the same range of lumpy ferrosilicon.Type: GrantFiled: January 23, 1997Date of Patent: November 30, 1999Assignee: Elkem ASAInventor: Lutz Stephan
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Patent number: 5978410Abstract: The present invention relates to a method for production of carbon electrodes where a first unbaked carbonaceous electrode paste containing a binder which cures at a temperature below 500.degree. C. is supplied to an annulus between a curing chamber having an inner cross section corresponding to the cross section of the electrode which is to be produced and an inner mould material, curing of the first electrode paste by means of supplying heat to the curing chamber, removing of elongated sections of the cured first electrode paste from the curing chamber. The lengths of the cured first electrode paste are mounted on the top of the electrode column in an electric smelting furnace, a second electrode paste is optionally supplied to the central opening of the cured body of the first electrode paste, whereby the cured body of the first electrode paste and the second electrode paste are baked into a solid carbon electrode in the area of supplying electric operating current to the electrode.Type: GrantFiled: August 26, 1997Date of Patent: November 2, 1999Assignee: Elkem ASAInventors: Johan Arnold Johansen, Reidar Ugland
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Patent number: 5833772Abstract: The invention relates to a rapidly solidified silicon-based alloy, containing 2-40% by weight Al, 2-45% by weight Ti, 0-10% by weight of one or more of the elements V, Cr, Fe, Mn, Ni, Co, 0-1% by weight of one or more of the elements B, Sr and P, the rest, except for impurities, being silicon in an amount of at least 35% by weight. The invention further relates to a method for producing such alloys where a molten alloy is provided and is solidified at a rate of solidification of at least 10.sup.3 .degree. C./second. Consolidated products are produced from the silicon-based alloy by forming articles from powdered alloy and consolidating the formed articles.Type: GrantFiled: November 8, 1996Date of Patent: November 10, 1998Assignee: Elkem ASAInventors: Leif L'Estrade, Karl Forwald, Gunnar Schussler
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Patent number: 5822358Abstract: This invention relates to a method for continuous production of a self-baking carbon electrode in direct connection with the smelting furnace wherein the electrode is consumed. Blocks of a first unbaked carbonaceous electrode paste are supplied to a curing chamber arranged at the upper end of the electrode, which curing chamber is open at its top and at its bottom and has an inner cross section corresponding to the cross section of the electrode which is to be produced, blocks of the first unbaked carbonaceous paste having a smaller diameter than the inner diameter of the curing chamber, supplying a second particulate unbaked carbonaceous electrode paste to the annulus between the curing chamber and the blocks of the first unbaked carbonaceous electrode paste, second electrode paste comprising a binder which cures at a lower temperature than the first carbonaceous paste by heating means arranged on the curing chamber.Type: GrantFiled: August 26, 1997Date of Patent: October 13, 1998Assignee: Elkem ASAInventor: Johan Arnold Johansen
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Patent number: 5788945Abstract: The present invention relates to a process for removing impurities from molten silicon by treatment of molten silicon contained in a vessel with a slag having the capability of removing the impurities, particularly boron from molten silicon wherein slag is continuously or substantially continuously added to the molten silicon and that the slag is continuously or substantially continuously inactivated or removed from the silicon melt as soon as equilibrium between the slag and molten silicon is reached with respect to the impurity elements or element to be removed.Type: GrantFiled: May 8, 1997Date of Patent: August 4, 1998Assignee: Elkem ASAInventor: Anders Schei
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Patent number: 5778021Abstract: The invention relates to a self-baking carbon electrode produced in direct connection with the furnace wherein it is consumed. The electrode comprises an outer casing made from an electrical conducting material, and having inner radial, vertical ribs. Carbonaceous unbaked paste is supplied to the casing, which paste is being baked to a solid electrode by means of electric current supplied to the electrode. The inner radial, vertical ribs consist of solid carbon sheets being affixed to the inside of the casing, said carbon sheets having a ratio between radial length and thickness of above 5:1.Type: GrantFiled: February 28, 1996Date of Patent: July 7, 1998Assignee: Elkem ASAInventor: Reidar Innv.ae butted.r
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Patent number: 5772728Abstract: The present invention relates to a method for upgrading silicon-containing solid residues obtained after leaching of copper from copper-containing residues from direct synthesis of organochlorosilanes. Solid residue, optionally together with an oxidation agent, is supplied to a smelting furnace where the residues are melted and form a molten metallic phase substantially containing silicon and a calcium silicate slag and tapping of the molten metallic phase and an inert slag from the smelting furnace.Type: GrantFiled: May 19, 1997Date of Patent: June 30, 1998Assignee: Elkem ASAInventors: Inger Johanne Eikeland, Roald Gundersen, Ragnhild Jensen
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Patent number: 5769939Abstract: The present invention relates to a cement-based injection grout containing microcement and water for consolidation and/or waterproofing fine granular soils, finally fissured soils and cracks in rocks or concrete structures. In addition to microcement and water the grout contains amorphous silica particles in an amount of 5-70% based on the weight of cement and 0-10% water-reducing agents based on the weight of the cement, said grout having a weight ratio between water and cement+amorphous silica between 2 and 8.Type: GrantFiled: June 4, 1997Date of Patent: June 23, 1998Assignee: Elkem ASAInventors: Eldar O. Dings.o slashed.yr, Per Fidjest.o slashed.l, Oddny J.o slashed.rgensen