Classifications

• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
  • C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
  • C21C7/0087—Treatment of slags covering the steel bath, e.g. for separating slag from the molten metal

Definitions

• the invention relates to a magnesium, carbon and aluminum
• Molten metal in a metallurgical vessel for example in a converter, in an electric arc furnace or in a pan, slag.
• the pig iron melt is separated from unwanted components before it is cast.
• the crude steel melt is produced by the melting of scrap, pig iron, molten iron and / or sponge iron and other raw materials.
• the slag must be specifically influenced or conditioned with regard to chemical and physical properties.
• the basicity ie the mass or molar ratio of the basic components to the other components of the paints (which can be calculated, for example, according to the following formula: [xCaO + MgO] /
• slag conditioners have a component that increases the basicity of the slag, in particular lime, dolomitic lime or dolomite.
• Metal melt can be reduced to the delivery of the converter.
• the process of applying the slag to the converter is also called
• Carbon monoxide gas provided in such a way.
• foaming of the slag layer is
• the object of the invention is to provide a slag conditioner by means of which the basicity and the MgO content of the slag can be increased rapidly in order to prevent the slag from attacking the refractory lining of the metallurgical vessel, in which the slag conditioner Molten metal with the on it
• Another object of the invention is to provide a
• Foaming of the paints can be achieved.
• Another object of the invention is to provide a
• a mixture or a chelate conditioner is provided for introduction into the slag contained in a molten metal in iron and steel metallurgy, the mixture comprising magnesium, carbon and aluminum in the following proportions by mass:
• MgO 45 to 90% by mass
• A1 2 0 3 1 -20% by mass.
• the mixture according to the invention or the slag conditioner according to the invention is suitable for introduction into slags
• Metal melts in any metallurgical vessel in particular for slags in converters, electric arc furnaces and pans.
• Magnesium and especially aluminum also as set forth herein other than in oxide form in the mixture according to the invention, for example in metallic form or, with regard to aluminum, in the form of carbide.
• the proportion of MgO in the mixture according to the invention By the proportion of MgO in the mixture according to the invention, the MgO saturation of the slag is reached faster, so that the corrosive attack of the slag is reduced to the refractory lining of the metallurgical vessel holding the molten metal. Furthermore, the viscosity of the slag increases with increasing MgO content.
• Magnesium is preferably present in the mixture according to the invention as an oxide, ie in the form of MgO.
• the proportions of magnesium in the mixture according to the invention are preferably present exclusively in the form of MgO, particularly preferably in the form of sintered or semi-molten magnesia.
• MgO can be present in the mixture according to the invention in proportions of at least 45% by mass, that is also for example in proportions of at least 48, 50, 52, 54, 56, 57, 58, 59, 60 or 61% by mass. Furthermore, MgO may be present in the mixture in proportions of at most 90% by mass, ie
• the proportion of carbon of the mixture according to the invention reacts when entering the mixture in the S chlacke with oxygen located in the S chlacke to carbon oxides, in particular to carbon monoxide CO and carbon dioxide C0 second
• the carbon of the mixture is oxidized promptly and vigorously with acid constituents of the slag, so that it spontaneously foams when the mixture is introduced.
• the slag thus rises, as in slag-foaming, in the air and covers the refractory lining of the metallurgical vessel.
• the Electric arc furnace is shielded by the increased volume of the foamed slag, the radiation of the arcs partially or completely with respect to the furnace wall. Due to the increased content of MgO, the slag simultaneously obtains the necessary viscosity in order to adhere to the wall during and after foaming.
• the carbon of the mixture can react directly with oxygen of the molten metal and withdraw oxygen from the molten metal.
• This extracted from the molten metal oxygen must not be removed later in additional steps by deoxidizer, such as aluminum, from the molten metal.
• At least part of the acid with which the carbon introduced from the mixture according to the invention into the paints reacts originates from iron oxides in the slag, which are reduced by the carbon to metallic iron.
• Iron oxides in contrast to metallic iron, however, are fluxes which reduce the viscosity of the paints.
• the carbon may be present substantially in pure form, for example in the form of graphite or coke, but also, for example, communitized with other constituents, for example with
• Aluminum carbide (Al 4 C 3 ) is present.
• Carbon is present in the mixture according to the invention in proportions of at least 5% by mass, ie for example also in fractions of
• carbon is present in the mixture according to the invention in proportions of at most 40% by mass, ie for example also in proportions of at most 38, 36, 34, 32, 31, 30, 29, 28, 27, 26 or 25% by mass.
• Aluminum calculated as Al 2 O 3 , in a proportion of at least
• aluminum calculated as Al 2 O 3
• the proportion of aluminum in the mixture according to the invention is herein, as stated above, calculated as Al 2 O 3 , wherein the inventive proportions of aluminum in the mixture j edoch preferably not in oxide form as Al 2 O 3 , but preferably partially, substantially or also completely in metallic form and / or in the form of carbide, ie as Al 4 C 3 .
• the inventive proportions of aluminum in the mixture j edoch preferably not in oxide form as Al 2 O 3 , but preferably partially, substantially or also completely in metallic form and / or in the form of carbide, ie as Al 4 C 3 .
• Aluminum carbide at the same time a carrier of both the proportion of aluminum and the carbon in the Mis monitoring.
• Aluminum carbide present the aluminum carbide component is particularly advantageous insofar as that both the aluminum and the
• Carbon of the aluminum carbide can react with the acid constituents of the slag and, as a result, oxidic constituents of the slag, in particular iron oxides, can be reduced. With corresponding reactions, the aluminum content of the aluminum carbide oxidizes to A1 2 0 3 and the carbon content of the aluminum carbide to C0 2 .
• Magnesium carbonate in magnesium oxide and carbon dioxide, the dolomite in magnesium and calcium oxide and carbon dioxide or magnesium hydroxide is split into magnesium oxide and water vapor.
• the carbon dioxide and the steam cause foaming of the slag.
• the mixture according to the invention is formulated in such a way that the component comprising magnesium, in particular in the form of MgO, is provided solely for increasing the basicity and the MgO content in the mixture, while the foaming of the slag is caused by other components of the mixture in particular by the components comprising carbon and aluminum. Furthermore, as no further carbonates have to be introduced into the primary metallurgical process by the slag conditioner according to the invention, the resource efficiency is higher, that is to say the specific consumption and the total weight to be introduced and transported into the slag
• the mixture has a proportion of magnesium carbonate of less than 10% by weight, that is to say, for example, a proportion of less than 9, 8, 7, 6, 5, 4, 3, 2, 1 or 0.5 mass%. %.
• the mixture has a content of Mg (OH) 2 of less than 10% by mass, that is to say for example also a fraction of 9, 8, 7, 6, 5, 4, 3, 2, 1 or 0, 5% by mass.
• the mixture has a proportion of dolomite, in particular of crude dolomite, below 10 mass%>, ie
• Calcium carbonate or limestone less than 10% by mass ie, for example, a proportion of 9, 8, 7, 6, 5, 4, 3, 2, 1 or 0, 5% by mass.
• the mixture is present in a relatively small particle size, for example at least 70% by mass, 80% by mass or at least 90% by mass or else 100% by mass in a particle size below 0, 5 mm.
• the particle size of the components of the mixture according to the invention is present below the particle sizes indicated below in the proportions by weight given in each case, it also being possible for the mixture according to the invention, for example, to fulfill only one of the following conditions with respect to its particle size:
• ⁇ 200 ⁇ at least 85 or 90 mass%> and at most 95 or 100
• ⁇ ⁇ at least 65 or 70 mass%> and not more than 75 or 80 mass%
• the mixture according to the invention has this very low mean particle size, it is possible to effect a particularly good and uniform distribution and, in particular, rapid dissolution of the mixture in a slag.
• it can be provided to provide the mixture in compacted or pressed form, for example in the form of pellets.
• a mixture according to the invention which in particular can have the previously described particle size distribution, is pressed into pellets without additions of additives.
• these pellets may have an almond-shaped, rod-shaped or spherical shape, for example with a maximum length of, for example, 50 mm, 40 mm or 30 mm.
• the pellets may also have, for example, a minimum diameter of 5, 10, 15, 20 or 25 mm.
• Grain size distribution can take effect there quickly.
• the mixture according to the invention has a proportion of calcium oxide (CaO), since by this the basicity of the slag can be further increased and the attack of S chlacke can be reduced to the refractory lining of the metallurgical vessel.
• the CaO of the mixture has, in particular, an advantageous basicity-reducing effect when the ratio of CaO to Si0 2 in the mixture
• the basicity of the slag can be increased by the CaO, in particular, if the ratio of mass fractions of CaO to Si0 2 in the mixture is not less than 0.7. It can therefore be provided that the ratio of the mass fractions of CaO to Si0 2 in the mixture according to the invention is not less than 0.7. Si0 2 can essentially be reached by impurities of the raw materials of the mixture according to the invention in this.
• the mixture comprises calcium oxide and silicon dioxide in the following proportions by weight:
• CaO can furthermore be present, for example, in proportions of at least 0, 1 or 0.2 or 0.5 or 1 or 1, 5 or 2% by weight in the mixture, and
• Si0 2 may be present, for example, in proportions of at least 0, 1 or 0.2 or 0.5 or 1 or 1, 5 or 2% by mass in the mixture and, for example, in proportions of at most 7, 6, 5, 4, 3 or 2.5 mass%>.
• the mixture in the form of pellets, wherein the mixture is compressed into pellets without the addition of additives.
• additives for pressing the mixture into pellets it may be provided to use CaO as such a pressing additive.
• the mixture contrary to the previously disclosed concept of the invention, according to which the mixture has proportions of CaO of at most 10% by mass of CaO, may have proportions of CaO of up to 40% by mass.
• the mixture preferably has no additive for pressing, so that the proportion of CaO in the mixture, as stated above, is not more than 10% by weight. It can be provided that the mixture contains iron oxides in the following
• Mass fractions includes:
• Iron oxide 0 to 7% by mass.
• Iron oxide stands for the sum of all iron oxides in the mixture, ie in particular FeO and Fe 2 0 3 , but for example Fe 3 0 4 and Fe 2 0.
• Iron oxides may also be present in the mixture in proportions of at least 0.1% by mass, 0.2% by mass, 0.4% by mass, 0.6% by mass or 0.8% by mass) and for example at most in proportions of 7% by mass, 6% by mass, 5% by mass, 4% by mass, 3% by mass, 2.8% by mass, 2.6% by mass, 2.4% by mass, 2.2 mass% or 2 mass%.
• Slag conditioners can be adversely affected by the presence of other components in the mixture.
• A1 2 0 3 comprises only small proportions of further components, for example in proportions of less than 5% by weight, 4% by weight, 3% by weight, 2.5% by weight, 2% by weight, 1, 5 mass%> or less than 1 mass%>.
• the mixture contains proportions of the following components below the below
• Mass shares includes:
• Magnesia-carbon products which have been used in the steel industry, in particular as wear linings of oxygen blowing converters, in electric arc furnaces or in pans, are in part suitable as raw material for the mixture according to the invention.
• correspondingly recycled magnesia-carbon products can be used partially, largely or exclusively as raw material for the mixture according to the invention.
• the invention also relates to the use of recycled gastric carbon products as a raw material for the mixture according to the invention or the use of such recycled magnesia-carbon products as inventive shell conditioners.
• magnesia especially sintered magnesia
• carbon especially graphite
• corundum especially carbon
• the invention furthermore relates to a method for conditioning a slag contained in a metallurgical vessel during iron and steel metallurgy, comprising the following steps:
• the mixture may, as described herein, be provided, for example, in compacted or compressed form, for example in the form of pellets.
• the mixture provided is added to the slag and sinks into it so that it can unfold its effect there according to the invention.
• the mixture according to the invention is suitable in principle as
• Slag conditioner for slag on a molten metal in any metallurgical vessel for example for molten metals in converters, electric arc furnaces or pans.
• the mixture according to the invention is particularly preferably used as a slag conditioner for thin paints on metal melts which are in a metallurgical vessel with a basic feed, ie in particular with a feed based on at least one of the following materials: magnesia, magnesia carbon, doloma or doloma -Carbon.
• the invention further relates to the use of a herein
• Components in the mass proportions according to Table 1 includes.
• the carbon was in the mixture in the form of graphite as well
• Aluminum was present in the mixture in the form of metallic aluminum and in the form of aluminum carbide.
• the raw materials used were exclusively recycled magnesia-carbon products.
• the mixture was provided in the form of almond-shaped pellets having a thickness of about 15 mm and a length of about 30 mm pressed without additional additives.
• the mixture was used as a slag conditioner for a slag on a molten metal found in an acid converter.
• the mixture was on the slag on the melt

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• Chemical & Material Sciences (AREA)
• Analytical Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)
• Carbon Steel Or Casting Steel Manufacturing (AREA)
• Treatment Of Steel In Its Molten State (AREA)

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Citations (3)

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• 2013
  • 2013-12-02 ES ES13195334.1T patent/ES2559024T3/es active Active
  • 2013-12-02 SI SI201330101T patent/SI2878685T1/sl unknown
  • 2013-12-02 PL PL13195334T patent/PL2878685T3/pl unknown
  • 2013-12-02 EP EP13195334.1A patent/EP2878685B9/de active Active
  • 2013-12-02 PT PT131953341T patent/PT2878685E/pt unknown
  • 2013-12-02 HU HUE13195334A patent/HUE026614T2/hu unknown
  • 2013-12-02 RS RS20150849A patent/RS54471B1/en unknown
• 2014
  • 2014-10-01 MX MX2016005055A patent/MX2016005055A/es unknown
  • 2014-10-01 CN CN201480062204.6A patent/CN105705662A/zh active Pending
  • 2014-10-01 WO PCT/EP2014/071022 patent/WO2015082093A1/de active Application Filing
  • 2014-10-01 US US15/038,735 patent/US20160376672A1/en not_active Abandoned
• 2015
  • 2015-12-31 HR HRP20151446TT patent/HRP20151446T1/hr unknown

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