Refractory lining arranged on bottom of metallurgical device for containing molten metal, method for providing refractory lining arranged on bottom of metallurgical device for containing molten metal, and metallurgical device for containing molten metal

Abstract

The invention relates to a refractory lining arranged on the bottom of a metallurgical device for accommodating molten metal, to a method for providing a refractory lining arranged on the bottom of a metallurgical device for accommodating molten metal, and to a metallurgical device for accommodating molten metal.

Description

[0001] The present invention relates to a refractory lining provided on the bottom of a metallurgical apparatus for containing molten metal, a method for providing a refractory lining provided on the bottom of a metallurgical apparatus for containing molten metal, and a metallurgical apparatus for containing molten metal.

[0002] In particular, an electric arc furnace (EAF) is also known as such a metallurgical apparatus for containing molten metal. Such an electric arc furnace is an industrial furnace in which an electric arc is generated, and the heat radiation thereof melts the solid metal present in the furnace, thereby producing molten metal in the furnace and making it available in the furnace. Electric arc furnaces are nowadays particularly used for melting and casting metals, especially including melting and recycling scrap iron and steel. Electric arc furnaces conventionally comprise a metal shell, the side walls of which may be at least partially further lined with refractory bricks. Nowadays, the bottoms of modern electric arc furnaces (also known as "hearths") are conventionally lined with unshaped refractory materials, i.e., so-called refractory ramming masses or refractory mixes. In particular, the bottoms of electric arc furnaces are nowadays lined with hearth masses.

[0003] The start-up procedure of a metallurgical apparatus (especially in the form of an electric arc furnace) for containing molten metal depends in particular on the quality of the refractory lining provided on the bottom of the metallurgical apparatus. Thus, the refractory lining provided on the bottom must be tightly sintered to prevent molten metal from passing through the refractory lining. This is important because the components of the molten metal passing through the refractory lining may damage the components of the electric arc furnace located below the refractory lining, such as the permanent lining or the metal shell of the electric arc furnace. In this regard, it is also particularly desirable that the refractory lining provided on the bottom is densely sintered at the lowest possible temperature during the start-up procedure, so as to thereby prevent molten metal from passing through the refractory lining provided on the bottom. In this regard, it may be desirable to provide a refractory lining that has been sintered at a low temperature. However, at the same time, refractory linings having a low sintering temperature particularly have the disadvantage of low refractoriness during operation. Although refractory linings having a low sintering temperature have the advantage of high tolerance to slag and molten metal during the start-up procedure, they are plagued by low tolerance to temperature changes and short lining life.

[0004] This dilemma - according to which the refractory lining should on the one hand have the lowest possible sintering temperature and on the other hand the highest possible refractoriness - cannot be satisfactorily solved in the prior art.

[0005] The object to be solved by the present invention is to provide a refractory lining that can be provided on the bottom of a metallurgical apparatus for containing molten metal, whereby the refractory lining should exhibit good sintering properties at low temperatures and at the same time have good refractoriness. In particular, the refractory lining should be densely sintered at low temperatures and at the same time exhibit good refractoriness, and further exhibit good tolerance to slag and molten metal, good tolerance to temperature changes, and good lining life.

[0006] To solve this object, according to the present invention, there is provided a refractory lining provided on the bottom of a metallurgical apparatus for containing molten metal, the refractory lining comprising: a first layer; and a second layer; wherein the first layer is provided on the bottom of the metallurgical apparatus; wherein the second layer is provided on the first layer; wherein the first layer and the second layer each have a chemical composition having MgO as the main oxide; wherein based on the mass of the first layer, the first layer has a chemical composition in which the proportion of Fe 2 O 3 is at most 2.8% by mass; and wherein based on the mass of the second layer, the second layer has a chemical composition in which the proportion of Fe 2 O 3 is at least 3.2% by mass.

[0007] Surprisingly, in the context of the present invention, it has been found that the above task can be solved by providing such a refractory lining.

[0008] The basic idea of the present invention is to provide a refractory lining comprising a plurality of layers. In particular, the refractory lining according to the present invention comprises at least two layers, namely a first layer and a second layer. Another basic idea of the present invention lies in that at least two layers of the refractory lining according to the present invention have different properties. According to the present invention, the first layer and the second layer have different properties. Another basic idea of the present invention is to provide that the first layer and the second layer have different properties with respect to their sintering behavior. In particular, it is envisaged that the second layer is sintered at a temperature lower than that of the first layer. This creates the possibility of solving the aforementioned dilemma. By sintering the second layer at a low temperature, a dense sintered layer of the refractory lining can be provided by the second layer even at a low temperature, thereby protecting the underlying area from the molten metal in the metallurgical apparatus. At the same time, the refractory properties of the first layer located below the second layer can be selected independently of the properties of the second layer. In this regard, the refractory properties of the first layer can be optimized independently of the refractory properties of the second layer. In particular, the refractory properties of the first layer can be optimized with respect to its tolerance to metal slag and molten metal, its tolerance to thermal shock, and its tolerance to high temperature.

[0009] In order to be able to impart good sintering behavior to the second layer, according to the present invention, the second layer has a relatively high proportion of Fe 2 O 3 . According to the present invention, based on the mass of the second layer, the second layer has a chemical composition in which the proportion of Fe 2 O 3 is at least 3.2% by mass. According to the present invention, it has been found that with such a minimum Fe 2 O3 Under this proportion, good sintering behavior can be imparted to the second layer.

[0010] In the case where the chemical composition is shown herein, this is the chemical composition measured on the fired substance (at 1025 °C) according to ISO 12677:2011-10.

[0011] According to a preferred embodiment, the second layer has a chemical composition with the content of Fe 2 O 3 in the range of 3.2 to 8.3% by mass, particularly preferably in the range of 3.2 to 6% by mass and even more preferably in the range of 3.2 to 4% by mass, in each case based on the mass of the second layer.

[0012] The second layer has a chemical composition with MgO as the main oxide. Thus, the chemical composition of the second layer is characterized by the fact that there are no other oxides with a higher mass fraction than MgO in the first layer. Preferably, based on the mass of the second layer, the second layer has a chemical composition with a proportion of MgO higher than 50% by mass. According to a preferred embodiment, the second layer has a chemical composition with a proportion of MgO in the range of 51 to 85% by mass, even more preferably in the range of 60 to 85% by mass, in each case based on the mass of the second layer.

[0013] According to the present invention, it has been found that the proportion of other oxides in the second layer also affects its sintering properties. In this regard, it can be provided that the other oxides also exist in the second layer in a specific proportion so as to be able to affect the sintering behavior of the second layer.

[0014] According to a preferred embodiment, the second layer has a chemical composition with a proportion of CaO in the range of 15 to 46% by mass, preferably in the range of 15 to 35% by mass, in each case based on the mass of the second layer.

[0015] According to a preferred embodiment, the second layer has a chemical composition with a proportion of SiO 2 in the range of 0.4 to 2.2% by mass, preferably in the range of 0.4 to 1.5% by mass, in each case based on the mass of the second layer.

[0016] According to a preferred embodiment, based on the mass of the second layer, the second layer has a chemical composition with a proportion of Al 2 O 3 in the range of 0.1 to 1.0% by mass.

[0017] According to one embodiment, it is provided that the second layer has a chemical composition with the proportion of the following oxides in the following ranges, each based on the mass of the second layer: Fe2 O 3 : 3.2 to 8.3% by mass; CaO: 15 to 46% by mass; SiO 2 : 0.4 to 2.2% by mass; Al 2 O 3 : 0.1 to 1.0% by mass; MgO: the balance to 100% by mass.

[0018] Preferably, one or more of the aforementioned oxides in the second layer may be present in the aforementioned preferred ranges accordingly.

[0019] According to the present invention, it has been found that, in particular, the oxide CaO in the second layer and SiO 2 have a special influence on its wear behavior. Preferably, in this regard, it can be provided that the mass ratio of CaO to SiO 2 in the second layer is in the range of 20 to 40, more preferably in the range of 22 to 34 and particularly preferably in the range of 24 to 32.

[0020] According to the present invention, it has been found that a correspondingly high mass fraction ratio of CaO to SiO 2 in the second layer can particularly effectively prevent the penetration of molten metal slag into and through the second layer and thus through the refractory lining according to the present invention.

[0021] The proportion of Fe 2 O 3 in the first layer is significantly lower than the proportion of Fe 2 O 3 in the second layer. This makes it possible to achieve particularly good fire resistance of the first layer. According to the present invention, it is provided that, based on the mass of the first layer, the first layer has a chemical composition in which the proportion of Fe 2 O 3 is at most 2.8% by mass. According to a preferred embodiment, the first layer has a chemical composition in which the proportion of Fe 2 O 3 is in the range of 0.2 to 2.8% by mass, even more preferably in the range of 1 to 2.8% by mass and particularly preferably in the range of 1 to 2.6% by mass, in each case based on the mass of the first layer.

[0022] As in the second layer, the chemical composition of the first layer is also characterized in that MgO is present as the main oxide, that is, there is no other oxide in the first layer having a higher mass fraction than MgO.

[0023] According to a preferred embodiment, it is provided that the first layer has a chemical composition with a proportion of MgO greater than 50% by mass, based on the mass of the first layer. According to a preferred embodiment, the first layer has a chemical composition with a proportion of MgO in the range of 65 to 98.6% by mass, even more preferably in the range of 65 to 80% by mass, in each case based on the mass of the first layer.

[0024] According to a preferred embodiment, the first layer has a chemical composition with a proportion of CaO in the range from 0.9 to 30% by mass, preferably in the range from 10 to 30% by mass, in each case based on the mass of the first layer.

[0025] According to a preferred embodiment, the first layer has SiO 2 A chemical composition in which the proportion of is in the range from 0.2 to 1% by mass, preferably in the range from 0.4 to 1% by mass, in each case based on the mass of the first layer.

[0026] According to a preferred embodiment, the first layer has Al 2 O 3 A chemical composition in which the proportion of is in the range from 0.05 to 0.4% by mass, preferably in the range from 0.05 to 0.2% by mass, in each case based on the mass of the first layer.

[0027] According to a preferred embodiment, it is provided that the first layer has a chemical composition with the following oxides in proportions within the following ranges, each based on the mass of the first layer: Fe 2 O 3 : 0.2 to 2.8 mass %; CaO: 0.9 to 30 mass%; SiO 2 : 0.2 to 1.0 mass %; Al 2 O 3 : 0.05 to 0.4 mass %; MgO: the balance is 100 mass %.

[0028] Preferably, one or more of the aforementioned oxides in the first layer may thus be present in the aforementioned preferred ranges.

[0029] According to a preferred embodiment, the CaO and SiO in the first layer 2 The mass ratio of is in the range of 4.5 to 50, particularly preferably in the range of 30 to 50.

[0030] Preferably, the second layer is arranged directly on the first layer. This means that there are no other layers or other components, such as other refractory materials or mortars, between the first layer and the second layer. In particular, this also has the following advantages: the first layer and the second layer can be optimally matched to each other, so that the refractory lining according to the invention can be provided in an optimized manner in terms of both its sintering behavior and its strength.

[0031] Preferably, no additional layer is arranged on the second layer, i.e., on the side of the second layer facing away from the first layer. This has the particular advantage that the refractory lining according to the invention can exhibit optimal sintering behavior on its upper side, which is achieved by the second layer. In this regard, the second layer is preferably exposed towards the top, i.e., on the side of the second layer facing away from the first layer, so that it can be optimally sintered during the start-up of the metallurgical device. When the refractory lining according to the invention is arranged at the bottom of the metallurgical device, the second layer preferably faces the space of the metallurgical device that accommodates the molten metal during the operation of the metallurgical device, so that the second layer is in direct contact with the molten metal during the operation of the metallurgical device. This allows the second layer to be rapidly sintered by the molten metal during the start-up process of the metallurgical device, so that the second layer immediately forms a barrier to prevent the molten metal from penetrating through the refractory lining.

[0032] The first layer is arranged on the bottom of the metallurgical device. The bottom of the metallurgical device can be designed according to the prior art. In the case where the metallurgical device is designed in the form of an electric arc furnace, the bottom of the metallurgical device can be designed according to the bottom of the electric arc furnace known in the prior art. In this regard, the bottom can be, for example, the bottom side section of the metal shell of the electric arc furnace, on which a permanent lining in the form of, for example, a refractory brick lining can also be arranged.

[0033] The first layer is preferably arranged directly on the bottom of the metallurgical device. In particular, it is preferred that no additional layer or refractory component, such as mortar, is arranged between the first layer and the bottom.

[0034] According to a preferred embodiment, the refractory lining according to the invention has a thickness in the range of 400 to 1,200 mm, particularly preferably in the range of 600 to 800 mm. According to the invention, it has been found that in the case of the refractory lining according to the invention having such a thickness, the bottom of the metallurgical device can be effectively protected against the molten metal and metal slag present in the metallurgical device, as well as against thermal erosion.

[0035] According to a preferred embodiment, it is provided that the second layer has a thickness in the range of 5 to 30% of the thickness of the refractory lining, more preferably in the range of 10 to 15% of the thickness of the refractory lining. According to the invention, it has been found that the second layer having such a thickness can effectively protect the underlying first layer and the bottom of the metallurgical device against the molten metal and metal slag.

[0036] Preferably, the second layer has a thickness in the range of 60 to 120 mm. According to the present invention, it has been found that by providing a second layer having such a thickness, the underlying first layer and the bottom of the metallurgical apparatus can be effectively protected from molten metal and metal slag.

[0037] Preferably, the first layer and the second layer are each in the form of a mass, i.e., unshaped refractory material. Preferably, the first layer and the second layer - especially when they also exist as masses - are not bonded, especially not bonded by an adhesive, and are not sintered (before starting the metallurgical apparatus in which the first layer and the second layer are used). A particular advantage of such first and second layers (which each exist as a mass) is that they are seamless, i.e., monolithic. In this regard, the first layer and the second layer preferably each exist as a monolithic layer. In this way, it is possible to prevent molten metal from passing through the refractory lining particularly effectively, and especially much more effectively than would be possible with shaped refractory products (e.g., in the form of bricks).

[0038] Preferably, the first layer and the second layer are in the form of dry masses, i.e., unshaped refractory material that is part of a binder- and water-free composition.

[0039] Particularly preferably, the first layer and the second layer are provided in the form of a hearth charge, especially as a dry hearth charge.

[0040] In order to be able to provide the first layer and the second layer with the properties according to the present invention, especially the chemical composition according to the present invention, in principle, all refractory raw materials known in the prior art can be used. It is readily apparent to the person skilled in the art which raw materials can be used to provide the first layer and the second layer with the properties mentioned herein, especially the chemical composition mentioned herein.

[0041] Preferably, the first layer and the second layer contain at least one of the following refractory raw materials: magnesia and calcined dolomite. Magnesia, i.e., a raw material based on magnesium oxide (MgO), can especially be in the form of at least one of sintered magnesia or fused magnesia.

[0042] Calcined dolomite, i.e., a raw material based on the oxides magnesium oxide and calcium oxide (CaO), can especially be present in the form of at least one of the raw materials sintered dolomite or fused dolomite.

[0043] According to an embodiment of the present invention, it can be preferably provided that the raw materials of the first layer and the second layer are present in a wide particle size distribution. According to one embodiment, it can be provided that the raw materials of the first layer and the second layer are present in the following particle sizes: wherein, based on the respective masses of the first layer and the second layer, at least 90% by mass is present in a particle size of less than 8 mm, 56 to 85% by mass is present in a particle size of less than 3.15 mm, 42 to 56% by mass is present in a particle size of less than 1.0 mm, and 6 to 22% by mass is present in a particle size of less than 0.063 mm.

[0044] Another subject of the present invention is to provide a refractory lining disposed on the bottom of a metallurgical apparatus for containing molten metal, and the method includes the following steps: Provide a metallurgical apparatus for containing molten metal, which includes: A bottom; Provide a refractory lining, the refractory lining includes: A first layer; and A second layer; wherein The first layer is adapted to be disposed on the bottom of the metallurgical apparatus; wherein The second layer is adapted to be disposed on the first layer; wherein Both the first layer and the second layer each have a chemical composition with MgO as the main oxide; wherein Based on the mass of the first layer, the first layer has a chemical composition with a proportion of Fe 2 O 3 of at most 2.8% by mass; and wherein based on the mass of the second layer, the second layer has a chemical composition with a proportion of Fe 2 O 3 of at least 3.2% by mass; Dispose the first layer on the bottom; and Dispose the second layer on the first layer.

[0045] The first layer and the second layer can be provided as disclosed herein.

[0046] In particular, the metallurgical apparatus can be an electric arc furnace as disclosed herein. In particular, the bottom of the metallurgical apparatus can be the bottom of the electric arc furnace. In particular, the bottom can be the bottom side portion of the metal shell of the electric arc furnace, as described herein, on which a permanent lining in the form of, for example, a refractory brick lining can also be arranged.

[0047] The first layer is configured to be disposed on the bottom of the metallurgical apparatus. In this regard, as disclosed herein, the first layer may be particularly preferably provided in the form of chunks, especially in the form of dry chunks. Preferably, in such a case, an unbonded and unsintered first layer is provided to be disposed on the bottom. As described above, providing the first layer in the form of such chunks also particularly has the advantage that it can be disposed on the bottom without seams, i.e., in a monolithic manner.

[0048] The first layer can be disposed on the bottom according to techniques known in the prior art. In the case where the first layer exists as chunks, it can be disposed on the bottom according to techniques known in the prior art for disposing chunks. In particular, the first layer can be disposed on the bottom in such a way that it forms a monolithic layer. For example, as known in the prior art, a suitable template can also be used to dispose the first layer on the bottom. As known in the prior art, after being disposed on the bottom, the first layer can be compacted, for example, by vibration or ramming. For example, the first layer can also be disposed on the bottom in layers in several steps.

[0049] The first layer is preferably disposed directly on the bottom of the metallurgical apparatus. In particular, it is preferred that no other layers or refractory components, such as mortar, are arranged between the first layer and the bottom.

[0050] The second layer is configured to be disposed on the first layer. In this regard, as disclosed herein, the second layer may be particularly preferably provided in the form of chunks, especially in the form of dry chunks. Preferably, in such a case, an unbonded and unsintered second layer is provided to be disposed on the first layer. As explained above, providing the second layer in the form of such chunks also particularly has the advantage that it can be disposed on the first layer without seams, i.e., in a monolithic manner.

[0051] The second layer can be disposed on the first layer according to techniques known in the prior art. In the case where the second layer exists as chunks, it can be disposed on the first layer according to techniques known in the prior art for disposing chunks. In particular, the second layer can be disposed on the first layer such that it forms a monolithic layer. For example, as known in the prior art, a suitable template can also be used to dispose the second layer on the first layer. As known in the prior art, after applying the second layer to the first layer, the second layer can also be compacted, for example, by vibration or ramming. For example, the second layer can also be disposed in layers in several steps.

[0052] Preferably, the second layer is disposed directly on the first layer. Thus, when the second layer is disposed on the first layer, there are no other layers or other components, such as other refractory materials or mortar, on the first layer.

[0053] Preferably, on the second layer, i.e., on the side of the second layer facing away from the first layer, no additional layer is provided. In this regard, the second layer is exposed upward after it is disposed on the first layer.

[0054] According to another step, it can be provided that the second layer disposed on the first layer is sintered. In particular, as described herein, it can be provided that the second layer is sintered only after it is disposed on the first layer. As is known in the prior art, the sintering of the second layer can be carried out during the start-up process of a metallurgical device (i.e., particularly in the form of an electric arc furnace). In particular, the second layer can be at least partially sintered by the molten metal formed on the first layer.

[0055] Another subject of the present invention is to provide a metallurgical device for containing molten metal, which comprises: a bottom; and a refractory lining; wherein the refractory lining is disposed on the bottom and comprises: a first layer; and a second layer; wherein the first layer is disposed on the bottom of the metallurgical container; wherein the second layer is disposed on the first layer; wherein the first layer and the second layer each have a chemical composition with MgO as the main oxide; wherein based on the mass of the first layer, the first layer has a chemical composition with the proportion of Fe 2 O 3 being at most 2.8% by mass; and wherein based on the mass of the second layer, the second layer has a chemical composition with the proportion of Fe 2 O 3 being at least 3.2% by mass.

[0056] As described herein, the metallurgical device can preferably be an electric arc furnace. In particular, the electric arc furnace can be a furnace for heating and melting scrap, hot metal, and / or direct reduced iron (DRI) via an electric arc. For example, the electric arc furnace can be a submerged arc furnace. In addition, as described herein, the bottom of the metallurgical device can in particular be designed as the bottom of an electric arc furnace known in the prior art.

[0057] The refractory lining can be configured as described herein.

[0058] Preferably, the refractory lining can be disposed on the bottom of the metallurgical device according to the present invention by the method according to the present invention.

[0059] Other features of the present invention will be apparent from the claims, the drawings, and the description of the drawings.

[0060] All features of the present invention can be combined individually or in any desired combination.

[0061] Embodiments of the present invention will be explained in more detail with reference to the accompanying drawings and related subsequent drawings.

[0062] Thereby it is shown that: Figure 1 A schematic exemplary embodiment of a metallurgical apparatus according to the present invention, which includes an exemplary embodiment of a refractory lining according to the present invention.

[0063] According to Figure 1 the exemplary embodiment of shows a metallurgical apparatus in the form of an electric arc furnace (1), which is shown in a perspective side sectional view.

[0064] As is known in the prior art, the electric arc furnace (1) includes a metal shell (2), and the metal shell (2) includes a bottom side section (3). A permanent lining (4) in the form of a refractory brick lining is arranged on the bottom side section (3) of the metal shell (2). The section (3) together with the permanent lining (4) arranged thereon forms the bottom (5) of the electric arc furnace (1). On the side walls, the lower section of the metal shell (2) is lined with a side wall wear-resistant lining (6) in the form of a brick lining made of refractory bricks. Surrounded by the electric arc furnace (1) is a furnace chamber (7) designed to accommodate molten metal.

[0065] In the region of the bottom (5), the electric arc furnace (1) further has components known in the prior art, such as a porous plug (11) and a bottom tapping (12).

[0066] An embodiment of the refractory lining (8) according to the present invention is arranged on the bottom (5). The refractory lining (8) includes a first layer (9) and a second layer (10).

[0067] The first layer (9) is directly arranged on the bottom (5). The first layer (9) is in the form of a dry hearth material arranged as a whole on the bottom (5).

[0068] The second layer (10) is directly arranged on the first layer (9) and is freely exposed on its top side. The second layer (10) thus directly faces the furnace chamber (7) surrounded by the electric arc furnace (1). The second layer (10) is in the form of a dry hearth material arranged as a whole on the first layer (9).

[0069] The refractory lining (8) has a thickness of 700 mm, wherein the second layer (10) has a thickness of 90 mm.

[0070] Both the first layer (9) and the second layer (10) are made of refractory raw materials in the form of sintered magnesite and sintered dolomite. These raw materials are selected in such masses and proportions that the first layer (9) and the second layer (10) each have a chemical composition according to the present invention, in particular an Fe 2 O 3 proportion of such quality and proportion.

[0071] Therefore, the first layer (9) has a chemical composition with the following proportions of oxides in the following amounts, each based on the mass of the first layer (9): Fe 2 O 3 : 2.4% by mass; CaO: 26% by mass; SiO 2 : 0.7% by mass; Al 2 O 3 : 0.1% by mass; MgO: 70.8% by mass.

[0072] The second layer (10) has a chemical composition with the following proportions of oxides in the following amounts, each based on the mass of the second layer (10): Fe 2 O 3 : 3.4% by mass; CaO: 23% by mass; SiO 2 : 0.8% by mass; Al 2 O 3 : 0.4% by mass; MgO: 72.4% by mass.

[0073] The particle size distribution of the first layer (9) and the second layer (10) is as follows: 90% < 8 mm, 70% < 3.15 mm, 55% < 1 mm, 20% < 0.063 mm (all the percentages are "mass %" relative to the respective masses of the first layer and the second layer).

[0074] To provide a refractory lining (8) on the bottom (5), an exemplary embodiment of the method according to the present invention was carried out.

[0075] In this regard, first, in order to place the first layer (9) and the second layer (10) on the bottom (5), the first layer (9) and the second layer (10) were provided as dry furnace bed materials.

[0076] Subsequently, the first layer (9) was placed on the bottom (5) in several steps according to the prior art, with each layer being vibration-compacted. In certain cases, especially if the slope of the slope exceeds 35°, a template can be used to place the material. After the compaction step, the first layer (9) exists as a whole layer on the bottom (5).

[0077] Subsequently, the second layer (10) is directly placed on the first layer (9), and the first layer (9) is integrally arranged on the bottom (5). If the slope inclination exceeds 35°, it can also be carried out in several steps with the aid of a template, and each layer is also vibration-compacted. After that, the second layer (10) is set as an integral layer on the first layer (9).

[0078] When the electric arc furnace (1) is subsequently started, it is found that the second layer (10) is tightly sintered at an early stage due to the molten metal formed in the furnace chamber (7), and can prevent the components of the molten metal and slag from infiltrating and passing through the refractory lining (8). In addition, the first layer (9) is proven to be highly resistant to molten metal, slag and temperature changes, and exhibits good high-temperature resistance.

Claims

1. A refractory lining (8) provided on the bottom (5) of a metallurgical apparatus (1) for containing molten metal, the refractory lining (8) comprising: 1.1 A first layer (9); and 1.2 A second layer (10); wherein 1.3 The first layer (9) is provided on the bottom (5) of the metallurgical apparatus (1); wherein 1.4 The second layer (10) is provided on the first layer (9); wherein 1.5 The first layer (9) and the second layer (10) each have a chemical composition with MgO as the main oxide; wherein 1.6 Based on the mass of the first layer (9), the first layer (9) has a chemical composition with a proportion of Fe 2 O 3 of at most 2.8% by mass; and wherein 1.7 A mass meter based on the second layer (10), the second layer (10) having a chemical composition with a proportion of Fe 2 O 3 of at least 3.2 mass %.

2. The refractory lining (8) according to claim 1, wherein the second layer (10) is directly disposed on the first layer (9).

3. The refractory lining (8) according to at least one of the preceding claims, wherein the first layer (9) has a chemical composition with a proportion of Fe 2 O 3 in the range of 0.2 to 2.8% by mass, based on the mass of the first layer (9).

4. The refractory lining (8) according to at least one of the preceding claims, wherein the second layer (10) has a chemical composition with a proportion of Fe 2 O 3 in the range of 3.2 to 8.3% by mass, based on the mass of the second layer (10).

5. The refractory lining (8) according to at least one of the preceding claims, wherein based on the respective masses of the first layer (9) and the second layer (10), the first layer (9) and the second layer (10) each have a chemical composition with a proportion of MgO higher than 50% by mass.

6. The refractory lining (8) according to at least one of the preceding claims, wherein the first layer (9) has a chemical composition with the proportions of the following oxides within the following ranges, each based on the mass of the first layer (9): Fe 2 O 3 : 0.2 to 2.8% by mass; CaO: 0.9 to 30% by mass; SiO 2 : 0.2 to 1.0 mass%; Al 2 O 3 : 0.05 to 0.4 mass%; MgO: the balance to 100% by mass.

7. The refractory lining (8) according to at least one of the preceding claims, wherein the second layer (10) has a chemical composition with the proportions of the following oxides within the following ranges, each based on the mass of the second layer (10): Fe 2 O 3 : 3.2 to 8.3 mass%; CaO: 15 to 46% by mass; SiO 2 : 0.4 to 2.2% by mass; Al 2 O 3 : 0.1 to 1.0 mass %; MgO: the balance to 100% by mass.

8. The refractory lining (8) according to at least one of the preceding claims, wherein the refractory lining (8) has a thickness in the range of 400 to 1,200 mm.

9. The refractory lining (8) according to at least one of the preceding claims, wherein the second layer (10) has a thickness in the range of 5 to 30% of the thickness of the refractory lining (8).

10. A method of providing a refractory lining (8) disposed on the bottom (5) of a metallurgical apparatus (1) for containing molten metal, the method comprising the following steps: A. Providing a metallurgical apparatus (1) for containing molten metal, which comprises: A.1 A bottom (5); B. Providing a refractory lining (8), the refractory lining (8) comprising: B.1 A first layer (9); and B.2 A second layer (10); wherein B.3 The first layer (9) is adapted to be disposed on the bottom (5) of the metallurgical apparatus (1); wherein B.4 The second layer (10) is adapted to be disposed on the first layer (9); wherein B.5 The first layer (9) and the second layer (10) each have a chemical composition with MgO as the main oxide; wherein B.6 Mass meter based on the first layer (9), the first layer (9) having a chemical composition with a proportion of Fe 2 O 3 of at most 2.8% by mass; and wherein B.7 Mass meter based on the second layer (10), the second layer (10) having a chemical composition with a proportion of Fe 2 O 3 of at least 3.2% by mass; C. Disposing the first layer (9) on the bottom (5); and D. Disposing the second layer (10) on the first layer (9).

11. The method according to claim 10, which further comprises the following additional step: E. Sintering the second layer (10) disposed on the first layer (9).

12. A metallurgical apparatus (1) for containing molten metal, which comprises: 12.1 A bottom (5); and 12.2 A refractory lining (8); wherein 12.2.1 The refractory lining (8) is disposed on the bottom (5) and comprises: 12.2.2 A first layer (9); and 12.2.3 A second layer (10); wherein 12.2.4 The first layer (9) is disposed on the bottom (5) of the metallurgical container; wherein The second layer (10) described in 12.2.5 is arranged on the first layer (9); wherein The first layer (9) and the second layer (10) each have a chemical composition with MgO as the main oxide; wherein 12.2.7 A mass meter based on the first layer (9), the first layer (9) having a chemical composition with a proportion of Fe 2 O 3 of at most 2.8% by mass; and wherein 12.2.8 A mass meter based on the second layer (10), the second layer (10) having a chemical composition with a proportion of Fe 2 O 3 of at least 3.2% by mass.

13. The metallurgical device (1) according to claim 12, which is an electric arc furnace.

14. The metallurgical device (1) according to at least one of claims 12 to 13, which has a refractory lining (8) according to at least one of claims 2 to 9.

15. The metallurgical device (1) according to at least one of claims 12 to 14, wherein the refractory lining (8) is arranged on the bottom (5) by the method according to at least one of claims 10 to 11.

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