Reducing Or Smelting Slag Or Dross As Starting Material Patents (Class 75/10.35)
  • Patent number: 10435769
    Abstract: A method for refining sulfidic copper concentrate includes feeding sulfidic copper concentrate and oxygen-bearing reaction gas and slag forming material into a reaction shaft of a suspension smelting furnace, collecting slag and blister copper in a settler of the suspension smelting furnace to form a blister layer containing blister copper and a slag layer, and discharging slag and blister copper separately from the settler of the suspension smelting furnace, so that slag is fed into an electric furnace. The method further includes feeding a part of the sulfidic copper concentrate into the electric furnace.
    Type: Grant
    Filed: January 15, 2019
    Date of Patent: October 8, 2019
    Assignee: OUTOTEC (FINLAND) OY
    Inventor: Akusti Jaatinen
  • Patent number: 9625871
    Abstract: A toner container includes a second lever. A toner supply portion includes a second actuating portion that, during a process in which the toner container is attached to the toner supply portion, switches the second lever from a third position to a fourth position. The waste toner collecting portion includes a third actuating portion and a stopper member. The third actuating portion, during the toner container attachment process, acts on the second lever disposed at the third position and prohibits an attachment of the toner container, and acts on the second lever disposed at the fourth position and permits an attachment of the toner container. The stopper member is prohibits an attachment of the toner container in a state of having been attached to a first attachment position, and permits the attachment in a state of having been attached to a second attachment position.
    Type: Grant
    Filed: June 23, 2016
    Date of Patent: April 18, 2017
    Assignee: KYOCERA Document Solutions Inc.
    Inventor: Masaki Sato
  • Patent number: 9512497
    Abstract: Disclosed herein is a method of reducing slag, including the steps of: examining the components of slag to be reduced, and setting a target composition ratio after reduction; determining the mixing ratio and input amount of a complex reducing agent of a plurality of reducing agents in accordance with the set target composition ratio to determine the complex reducing agent; and supplying the complex reducing agent into molten slag to reduce the slag. The method is advantageous in that the reduction efficiency of slag can be maximized, various kinds of reducing agents can be efficiently used, and the recovery amount of valuable metals can be increased, thus reducing cost.
    Type: Grant
    Filed: July 29, 2014
    Date of Patent: December 6, 2016
    Assignees: Hyundai Steel Company, Inha-Industry Partnership Institute
    Inventors: Joon-Seong Ki, Dong-Kyung Shin, Byung-Don You, Seong-Woong Joo, Seong-Hun Hong, Jin-Ill Hwang
  • Publication number: 20150135896
    Abstract: The method of reduction processing of steel-making slag, includes: a hot steel-making slag inflow process of continuously or intermittently charging, from a slag supplying container, hot steel-making slag to a molten slag layer on a molten iron contained in an electric furnace while adjusting an amount of inflow with the slag supplying container; a reducing agent supplying process of supplying a reducing agent to the molten slag layer; an electrifying and heating process of heating the molten iron and the molten slag layer through application of electric power; and a reduction process of continuing reduction processing of the hot steel-making slag in a non-oxidizing atmosphere while intermittently discharging either one or both of the molten iron or molten slag of the molten slag layer.
    Type: Application
    Filed: June 27, 2013
    Publication date: May 21, 2015
    Inventors: Toshiya Harada, Takashi Arai, Hiroshi Hirata
  • Publication number: 20150122082
    Abstract: The invention relates to a method for processing slags of non-ferrous metallurgy, containing iron and valuable metals, to produce clean slag that is free of detrimental substances and valuable metals and suitable as it is for use as a raw material or construction material. Slag is reduced in a reduction furnace (18) with the help of reducing agents (19) so far that at least 5% of the iron of the slag is reduced into metal. At the same time, some of the valuable metals, such as zinc, lead, arsenic and cadmium, vaporize. The contents of the reduction furnace (18) are continuously mixed to prevent separation of a metallic phase from the slag. The generated slag-metal mixture (21) is tapped off from the reduction furnace (18), cooled, crushed and ground to a finer size. Finally, a metal fraction (26) is separated from a clean slag (25).
    Type: Application
    Filed: April 15, 2013
    Publication date: May 7, 2015
    Inventors: Maija-Leena Metsarinta, Jussi Liipo, Pekka Kurki, Madeleine Scheidema
  • Patent number: 8771396
    Abstract: A method for producing blister copper directly from copper concentrate is provided, comprising: a) adding copper concentrate, copper matte, slagging material, oxygen enriched air, endothermic material to an upper segment of the reaction furnace; b) adding reducing agent to the lower segment space of the reaction furnace; c) directing the produced hot coke and liquid slag into an electric furnace, and adding copper concentrate into the electric furnace to generate an electric furnace slag and copper matte; d) the copper matte being granulated and finely ground, then re-fed into the reaction furnace.
    Type: Grant
    Filed: November 14, 2012
    Date of Patent: July 8, 2014
    Assignee: Xiangguang Copper Co., Ltd.
    Inventors: Songlin Zhou, Weidong Liu, Zheling Ge
  • Publication number: 20130269481
    Abstract: The present invention provides a method for producing blister copper directly from copper concentrate, comprising: a) adding copper concentrate, copper matte, slagging material, oxygen enriched air, endothermic material to a upper segment of the reaction furnace; b) adding reducing agent to the lower segment space of the reaction furnace; c) directing the produced hot coke and liquid slag into an electric furnace, and adding copper concentrate into the electric furnace to generate an electric furnace slag and copper matte; d) the copper matte being granulated and finely ground, then re-fed into the reaction furnace. The addition of reducing agent in the lower segment will not increase the heat load of the reaction furnace since the reducing agent does not burn.
    Type: Application
    Filed: November 14, 2012
    Publication date: October 17, 2013
    Applicant: Xiangguang Copper Co., Ltd.
    Inventors: Songlin Zhou, Weidong Liu, Zheling Ge
  • Publication number: 20130186236
    Abstract: A process and an apparatus are disclosed for improved recovery of metal from hot and cold dross, wherein a dross-treating furnace is provided with a filling material with capacity to store heat. This filling material is preheated to a desired temperature by injection of an oxidizing gas to burn non-recoverable metal remaining in the filling material after tapping of the recoverable metal contained in the dross and discharging of the treatment residue. When dross is treated in such furnace, the heat emanating by conduction from the filling material is sufficient to melt and separate the recoverable metal contained in the dross, without addition of an external heat source, such as fuel or gas burners, plasma torches or electric arcs and without use of any salt fluxes. Furthermore, the recovered metal being in the molten state can be fed to the molten metal holding furnace without cooling the melt.
    Type: Application
    Filed: October 18, 2012
    Publication date: July 25, 2013
    Applicant: PYROGENESIS CANADA INC.
    Inventor: Pyrogenesis Canada Inc.
  • Patent number: 8298317
    Abstract: A steelmaking process is disclosed. The process includes producing molten steel and molten steelmaking slag in a steelmaking process, the steelmaking slag including iron units and flux units, and thereafter producing molten iron in a molten bath based direct smelting process using a substantial portion of the steelmaking slag as part of the feed material requirements for the direct smelting process. A direct smelting process is also disclosed. The process includes pre-treating ferrous material including steelmaking slag and thereafter direct smelting molten iron using the pretreated ferrous material as part of the feed material for the process.
    Type: Grant
    Filed: April 7, 2011
    Date of Patent: October 30, 2012
    Assignee: Technological Resources Pty. Limited
    Inventors: Rodney James Dry, Robin John Batterham
  • Patent number: 8157884
    Abstract: The invention concerns a method for the continuous or discontinuous extraction of a metal or several metals from a slag that contains the metal or a compound of the metal, in which the liquefied metal-containing slag is heated in a primary or secondary smelting unit (1). To provide an improved method for extracting metals, especially copper, from slags, the invention provides that the metal-containing slag is heated in a primary or secondary smelting unit (1) designed as an alternating-current electric furnace, and the molten material is then fed from the primary or secondary smelting unit (1) into a furnace (2) designed as a direct-current electric furnace, in which the metal to be extracted is subjected to an electrolytic separation, where a reducing agent in the form of calcium silicide (CaSi), calcium carbide (CaC2), ferrosilicon (FeO), aluminum (Al), and/or reducing gases is added and/or injected into the primary or secondary smelting unit (1).
    Type: Grant
    Filed: October 25, 2007
    Date of Patent: April 17, 2012
    Assignee: SMS Siemag Aktiengesellschaft
    Inventors: Rolf Degel, Jürgen Kunze
  • Patent number: 8133295
    Abstract: A method for producing lead involves feeding lead concentrate, flux and solid fuel passing to a feed preparation unit. The prepared, mixed feed is then passed to a lead smelting furnace, such as an ISASMELT furnace or other top entry, submerged lance furnace. Air or oxygen, is injected into the molten charge in the ISASMELT furnace via the submerged lance. The feed mixture is converted into lead bullion and a lead-containing slag. The slag removed from the furnace is formed into lumps having a desirable size range. The slag lumps, together with coke and flux are fed into a blast furnace. In the blast furnace, the slag is converted into lead bullion and discard slag. The lead bullion removed may be subsequently fed to a lead refinery for further treatment.
    Type: Grant
    Filed: April 4, 2008
    Date of Patent: March 13, 2012
    Assignees: Yunnan Metallurgical Group, Xstrata Technology Pty Ltd
    Inventors: Philip Scott Arthur, William John Errington
  • Publication number: 20110203413
    Abstract: A process for the treatment of loads or residues of non-ferrous metals and their alloys includes the steps of loading of scraps or dross to be processed and heating the load and melting the metal. The process additionally includes revolving the heated load, tapping the molten metal and emptying a cavity of the furnace. Heating of the load or residues to a temperature above the melting temperature of the metal or non-ferrous alloy to be recovered is carried out by means of a free burning convective arc which is independent from the supply of external gas to the process, and which may dispense with the use of melting salts.
    Type: Application
    Filed: May 5, 2011
    Publication date: August 25, 2011
    Applicants: Fundacao de Amparo a Pesquisa do Estado de Sao Paulo - Fapesp, Instituto de Pesquisa Tecnologicas do Est. S. Paulo S/A - IPT
    Inventors: Antônio Carlos da CRUZ, Oskar Wessel BENDER
  • Patent number: 7955409
    Abstract: A method of smelting copper includes: a generating step of generating blister and slag from copper matte by charging the copper matte into a smelting furnace and oxidizing the copper matte; a first refining step of refining another blister from the slag by reduction in an electrical furnace; and a charging step of charging the slag into one of the smelting furnace or another smelting furnace for treating copper concentrate and generating matte as repeating flux if copper grade of slag generated in the first refining step is higher than 0.8 weight %.
    Type: Grant
    Filed: July 14, 2009
    Date of Patent: June 7, 2011
    Assignee: Pan Pacific Copper Co., Ltd.
    Inventors: Kenta Nakakado, Makoto Hamamoto, Seiichi Watanabe
  • Patent number: 7935172
    Abstract: A steelmaking process is disclosed. The process includes producing molten steel and molten steelmaking slag in a steelmaking process, the steelmaking slag including iron units and flux units, and thereafter producing molten iron in a molten bath based direct smelting process using a substantial portion of the steelmaking slag as part of the feed material requirements for the direct smelting process. A direct smelting process is also disclosed. The process includes pre-treating ferrous material including steelmaking slag and thereafter direct smelting molten iron using the pretreated ferrous material as part of the feed material for the process.
    Type: Grant
    Filed: January 31, 2005
    Date of Patent: May 3, 2011
    Assignee: Technological Resources Pty Limited
    Inventors: Rodney James Dry, Robin John Batterham
  • Patent number: 7918917
    Abstract: A method of smelting copper includes: a generating step of generating blister and calcium ferrite slag from copper matte by charging the copper matte into a smelting furnace and oxidizing the copper matte; and a refining step of refining another blister from the calcium ferrite slag in an electrical furnace under a temperature condition of 1250 degrees C. to 1350 degrees C. and under a reductive atmosphere condition of oxygen partial pressure logPO2??9.3.
    Type: Grant
    Filed: July 14, 2009
    Date of Patent: April 5, 2011
    Assignee: Pan Pacific Copper Co., Ltd.
    Inventors: Kenta Nakakado, Makoto Hamamoto, Seiichi Watanabe
  • Publication number: 20100089202
    Abstract: During the production of stainless steel, a slag is formed during the melting of the solid material in the electric arc furnace, the slag having a high degree of metal oxides, particularly chromium oxide. The chromium concentration often reaches values of more than 30%. Currently, such slags cannot be reduced to a desired degree due to their composition. In order to minimize the resulting high loss of recyclable material, the invention provides to charge the electric arc furnace with pellets, or briquettes (8), which are made of a defined mixture of an iron carrier as the ballast material, carbon, or carbon and silicon, as the reducing agent, and a binder, wherein they react beneath the slag layer (7) in the steel melt (6) with the metal oxides of the slag (7), particularly with the chromium oxide present, in a floating, chemical, and reducing manner. The reaction gases (12) produced in the process, which are mainly made of carbon monoxide, advantageously support a foaming of the slag (7).
    Type: Application
    Filed: January 10, 2008
    Publication date: April 15, 2010
    Applicant: SMS SIEMAG AKTIENGESELLSCHAFT
    Inventors: Johann Reichel, Lutz Rose
  • Publication number: 20090249919
    Abstract: The invention concerns a method for the continuous or discontinuous extraction of a metal or several metals from a slag that contains the metal or a compound of the metal, in which the liquefied metal-containing slag is heated in a primary or secondary smelting unit (1). To provide an improved method for extracting metals, especially copper, from slags, the invention provides that the metal-containing slag is heated in a primary or secondary smelting unit (1) designed as an alternating-current electric furnace, and the molten material is then fed from the primary or secondary smelting unit (1) into a furnace (2) designed as a direct-current electric furnace, in which the metal to be extracted is subjected to an electrolytic separation, where a reducing agent in the form of calcium silicide (CaSi), calcium carbide (CaC2), ferrosilicon (FeO), aluminum (Al), and/or reducing gases is added and/or injected into the primary or secondary smelting unit (1).
    Type: Application
    Filed: October 25, 2007
    Publication date: October 8, 2009
    Inventors: Rolf Degel, Jürgen Kunze
  • Patent number: 7597736
    Abstract: In a process for utilizing slag containing oxidic iron particles, adding a reducing agent and reducing oxidic iron particles of the slag are charging the slag into a reactor vessel onto a residual iron metal containing dissolved carbon, slowly and continuously over an extended period of time, electric heating the slag and the iron melt over an extended period of time, injecting a carbon-containing reducing agent with inert gas over an extended period of time by a lance into a region close to the boundary surface between the slag and the iron melt or directly into the iron melt, dissolving the carbon of the reducing agent in the iron melt and reducing oxidic iron particles of the slag with metallic iron and CO being formed, over an extended period of time, forming a foamed slag by the resulting CO over an extended period of time, introducing an oxygen-containing gas or oxygen into the foamed slag and postcombustion of CO to CO2 over an extended period of time, bottom flushing the reactor vessel with inert gas
    Type: Grant
    Filed: November 16, 2005
    Date of Patent: October 6, 2009
    Assignee: Siemens Vai Metals Technologies GmbH & Co
    Inventors: Alexander Fleischanderl, Udo Gennari
  • Publication number: 20090211398
    Abstract: The invention is directed to a process for extracting a metal from a slag containing said metal, wherein the liquefied metal-containing slag is heated in at least one electric arc furnace (1, 2). In order provide an improved method for recovering especially copper from slags, the invention provides that the metal-containing slag is heated in a first furnace (1) constructed as an AC electric furnace or a DC electric furnace, and the melt is introduced from the first furnace (1) into a second furnace (2) which is constructed as a DC electric furnace. Further, the invention is directed to an arrangement for extracting a metal from a slag containing said metal.
    Type: Application
    Filed: June 8, 2006
    Publication date: August 27, 2009
    Applicant: SMS DEMAG AG
    Inventors: Juergen Kunze, Rolf Degel, Dieter Borgwardt, Andrzej Warczok, Gabriel Angel Riveros Urzua
  • Publication number: 20080250899
    Abstract: The invention provides a method of processing a starting material in the form of a metal oxide-containing raw metallurgical slag to obtain a processed slag product. The method includes admixing the raw slag with a reductant to obtain a reaction mixture and heating the reaction mixture to cause the reductant to reduce the metal oxide in the slag, to obtain molten metal, in particular containing f erromanganese, and molten processed slag, in particular having a manganese content of at most 10% by mass. The method further includes separating the molten processed slag from the molten metal and causing or allowing the molten processed slag to solidify, thereby to obtain a solid processed slag product. This processed slag product may be, as desired, a filler for use in brick-making or for use in formulating a ready-mix concrete, an extender for extending a cement or for producing a blended cement, or an aggregate for use in the construction or building industry.
    Type: Application
    Filed: August 28, 2006
    Publication date: October 16, 2008
    Inventor: Anton Mecchi
  • Publication number: 20080250900
    Abstract: A method for producing lead involves feeding lead concentrate, flux and solid fuel passing to a feed preparation unit. The prepared, mixed feed is then passed to a lead smelting furnace, such as an ISASMELT furnace or other top entry, submerged lance furnace. Air or oxygen, is injected into the molten charge in the ISASMELT furnace via the submerged lance. The feed mixture is converted into lead bullion and a lead-containing slag. The slag removed from the furnace is formed into lumps having a desirable size range. The slag lumps, together with coke and flux are fed into a blast furnace. In the blast furnace, the slag is converted into lead bullion and discard slag. The lead bullion removed may be subsequently fed to a lead refinery for further treatment.
    Type: Application
    Filed: April 4, 2008
    Publication date: October 16, 2008
    Inventors: Philip Scott Arthur, William John Errington
  • Patent number: 7435281
    Abstract: A pyrometallurgic process for the treatment of post-steelwork residues, comprises the following phases: preparing a furnace (1) of the electric type, suitable for the introduction of the residues; preparing the residues, for example in a hopper with the possibility of mixing with additives and reaction elements; introducing the residues, together with suitable additives and chemical reagents, into the furnace (1); introducing directly into the slag, by means of lances (4), additives, flushing and reaction elements to correct the composition of the slag (7); reacting the residues with the slag (7) to obtain: a) separation of the liquid metallic phases which are added to the metal bath (6) to form a sellable liquid metal; b) separation of the metallic volatile elements in vapour phase which, when transferred to the free zone of the furnace (1) recombine with the oxygen for the formation of oxides and consequently of powder.
    Type: Grant
    Filed: February 10, 2005
    Date of Patent: October 14, 2008
    Assignee: Techint Compagnia Tecnica Internazionale S.p.A.
    Inventors: Marcello Pozzi, Carlo Raggio, Loredana Di Sante
  • Publication number: 20080156144
    Abstract: The present invention relates to a method for reducing to metallic chromium the chromium oxide material found in slag formed in an electric arc furnace during the process of making stainless steel in that furnace. The chromium oxide content of the slag can be effectively reduced to a relatively low concentration by maintaining the slag in a liquid phase while at the same time blowing into the furnace via a carrier gas certain amounts of powdered aluminum dross. In particular, powdered aluminum dross can be blown into the furnace in amounts ranging from about 10 to 20 kg of dross per ton of molten steel in the furnace. Alternatively, powdered aluminum dross can be blown into the furnace in a thrown-in amount which satisfies the equation: 0.5?[Thrown-In Al dross (ton)×100]/[Slag in Furnace (ton)×Cr2O3 (wt %)]?1.0. Via such a method used during the stainless steel making process, the recovery of valuable chromium and the rate of chromium oxide reduction can be increased.
    Type: Application
    Filed: December 26, 2007
    Publication date: July 3, 2008
    Applicant: POSCO
    Inventors: Sang-Yuel JUNG, Yong Hwan KIM, Sun-Min BYUN, Sang-Beom LEE, Hyun-Chul CHUN
  • Patent number: 7172640
    Abstract: In a method and a device for melting down metal-containing material, preferably fine-particulate metal-containing material, such as sponge iron, in a metallurgical melting furnace (1), wherein, in an interior space (11) of the melting furnace (1), a metal melt (5) and a slag layer (6) floating on top of the metal melt (5) are maintained, the metal-containing material is added by means of a supply means dipping into the slag layer (6) and energy is added in the form of electric arcs (14), the metal-containing material is charged directly into the central region (Z) of the melting furnace (1) by means of at least one charging tube (8) exclusively serving for conveying material via the charging tube outlet (9) of the same, the electric arcs (14) are directed obliquely towards the metal melt (5) against the central region (Z) of the melting furnace (1) and the metal-containing material is melted in the slag layer (6) and a mixed process slag-metal melt is maintained in the region of the charging tube outlet (9).
    Type: Grant
    Filed: October 22, 2001
    Date of Patent: February 6, 2007
    Assignee: Voest-Alpine Industrieanlagenbau GmbH
    Inventors: Harald Berger, Peter Mittag, Bernhard Aigner
  • Patent number: 6761749
    Abstract: The invention relates to a method of producing blister copper pyrometallurgically in a suspension reactor directly from its sulfidic concentrate. According to the method the copper sulfide concentrate is fed into a suspension reactor, into which cooled and finely ground copper matte is also fed in order to bind the heat released from the concentrate.
    Type: Grant
    Filed: September 30, 2002
    Date of Patent: July 13, 2004
    Assignee: Outokumpu Oyj
    Inventors: Jaakko Poijärvi, Tarmo Mäntymäki
  • Publication number: 20040099091
    Abstract: The invention relates to a method for producing stainless steels, in particular steels containing chromium and chromium-nickel. The method is carried out in a melting device containing a metallurgical vessel, or in a melting device (1) containing at least two vessels (2, 3) for supplying a steel-casting installation, an electric arc furnace process (1) and an air-refining process taking place alternately in the two vessels (2, 3). To improve the efficiency of a method of this type, the aim of the invention is to carry out a reversible treatment of unreduced converter slag in the electric-arc furnace mode. To achieve this, in the first treatment stage, the slag (19) with a high chromium content is melted together with the added charge, the slag is then reduced during the melting process with the silicon and carbon under favourable thermodynamic conditions of the arc, once the slag has reached a minimum temperature of 1,490° C. and the slag is subsequently removed.
    Type: Application
    Filed: July 21, 2003
    Publication date: May 27, 2004
    Inventors: Karl Reiner Gotzinger, Stefan Lembe, Johann Reichel, Bernt Rollinger
  • Patent number: 6679931
    Abstract: A method for recovering metallic chromium from slags which contain chromium oxide from converter processes, such as AOD, MRP, AOD-L, MRP-L, CLU, ASM, Conarc stainless steel or vacuum processes, such as VOD, SS-VOD, RH, RH with lanze, includes drawing off the slag which is produced at the end of a blowing or treatment operation in a converter or a vacuum installation in unreduced form. The slag is charged into an electric furnace, which is also charged with a standard charge of scrap and, if appropriate, dust residues. Carbon and, if appropriate, silicon are additionally added to the electric furnace.
    Type: Grant
    Filed: April 9, 2002
    Date of Patent: January 20, 2004
    Assignee: SMS Demag AG
    Inventors: Karl Götzinger, Jan Reichel
  • Patent number: 6506225
    Abstract: In a steelmaking process in which, in order to desulfurize iron melts (4) using a strongly basic slag in a desulfurization vessel (7), the desulfurization slag (8) is brought to a temperature of from 1400-1800° C.
    Type: Grant
    Filed: November 28, 2000
    Date of Patent: January 14, 2003
    Assignee: Voest-Alpine Industrieanlagenbau GmbH
    Inventor: Hermann Pirker
  • Publication number: 20020083794
    Abstract: In a method and a device for melting down metal-containing material, preferably fine-particulate metal-containing material, such as sponge iron, in a metallurgical melting furnace (1), wherein, in an interior space (11) of the melting furnace (1), a metal melt (5) and a slag layer (6) floating on top of the metal melt (5) are maintained, the metal-containing material is added by means of a supply means dipping into the slag layer (6) and energy is added in the form of electric arcs (14), the metal-containing material is charged directly into the central region (Z) of the melting furnace (1) by means of at least one charging tube (8) exclusively serving for conveying material via the charging tube outlet (9) of the same, the electric arcs (14) are directed obliquely towards the metal melt (5) against the central region (Z) of the melting furnace (1) and the metal-containing material is melted in the slag layer (6) and a mixed process slag-metal melt is maintained in the region of the charging tube outlet (9).
    Type: Application
    Filed: October 22, 2001
    Publication date: July 4, 2002
    Inventors: Harald Berger, Peter Mittag, Bernhard Aigner
  • Patent number: 6409793
    Abstract: A method for processing steel slags and optionally iron carriers such as, e.g., electric furnace slags, converter slags, dusts derived from steel production, mill scale or secondary metallurgical residues, in which the molten steel slags or iron carriers are supplemented with chromium ores or chromium-containing and/or nickel-containing dusts in order to adjust a slag basicity of 1.2 to 1.6, whereby the bath temperature is maintained at above 1600° C., in particular between 1650° C. and 1800° C., and a carbon-containing iron bath is provided or formed. In addition to environmentally safe slags, a high-grade ferrochromium alloy may be recovered, thus enhancing the economy of the method.
    Type: Grant
    Filed: December 22, 2000
    Date of Patent: June 25, 2002
    Assignee: “Holderbank” Financiere Glarus AG
    Inventor: Alfred Edlinger