Abstract: To produce manganese containing ferroalloy for steel production, an agglomeration mixture is produced which comprises chromite ore concentrate and manganese ore fines with a grain size smaller than 6-9 mm. The mixture is agglomerated to produce green agglomeration products, such as pellets or other types of agglomerates. The green agglomeration products are sintered in a steel belt sintering furnace to produce either sinter or sintered pellets. The sinter or sintered pellets are smelted in a submerged arc furnace to produce manganese and chromium containing ferroalloy. The ferroalloy produced by the method comprises 6.0-35 w-% manganese and 31-54 w-% chromium.
Type:
Grant
Filed:
December 16, 2014
Date of Patent:
November 13, 2018
Assignee:
OUTOTEC (FINLAND) OY
Inventors:
Helge Krogerus, Pasi Mäkelä, Visa Kivinen
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).
Abstract: A process and material for producing foamed slag by which the foaming of a slag with a high chromium oxide content can be achieved. An electric arc furnace is charged with a mixture of metal oxides and carbon and, below the slag at the metal-slag interface, the metal oxide is reduced by carbon and limestone and becomes thermally discordant. The occurring gases cause the slag to foam due to the formation of bubbles.
Abstract: The invention relates to a process for producing nodular cast iron with a high number of graphic nodules. This process comprises the following steps: preparing molten base iron for wasting castings of nodular cast iron; adding Mg to the molten base iron; inoculating the casting stream with a first inoculant when casting the cast iron into a casting mold. According to the invention, between the addition of the Mg and the inoculation of the casting stream, a preliminary inoculation using a further inoculant is carried out as an additional step. The invention also relates to a casting obtained by using this process.
Type:
Grant
Filed:
February 12, 2001
Date of Patent:
March 18, 2003
Assignee:
Corus Technology B.V.
Inventors:
Pieter Cornelis Van Eldijk, Frans-Benoni Lietaert
Abstract: 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.
Abstract: A process for producing stainless steels, particularly special steels containing chromium and chromium-nickel, in a smelting arrangement having at least two vessels, for supplying a steel foundry. A charge having mostly iron-containing raw scrap materials and partially carbon-containing alloy carriers is melted in a first vessel. At a temperature of 1460° C., the melt is decarburized by the injection of oxygen so as to reduce the carbon content to less than 0.3%. The melt is heated to a tapping temperature of between 1620° C. to 1720° C. and the carbon content is subsequently reduced to 0.1%. A second charge is melted in a second vessel simultaneously with the decarburizing of the first charge in the first vessel.
Type:
Grant
Filed:
July 31, 1998
Date of Patent:
May 29, 2001
Assignee:
Mannesmann AG
Inventors:
Lutz Rose, Hartmut Vorwerk, Horst Kappes, Klaus Ulrich