Metal Melting Furnace

Abstract

Provided is a molten metal furnace that can prevent or suppress molten metal leakage and can suppress heat dissipation from the furnace body. A molten metal furnace has an outer wall (1) on its outer peripheral part and has a molten metal storage part for holding molten metal (M). It is characterized in that two or more lining layers are arranged on the inner wall of the molten metal furnace forming the molten metal storage part. Among the lining layers, a first lining layer (10) forming the surface in contact with the molten metal is made of a refractory material, and sealing materials (50) are provided at at least two boundaries between the first lining layer (10) and the outer wall (1). The lining layer between the sealing materials (50), (50) is a heat insulating board containing at least silica (SiO2).

Description

Technical Field

[0001] The present invention relates to a metal melting furnace for holding a molten metal such as aluminum, aluminum alloy, and non-ferrous metal. Background Art

[0002] Conventionally, there has been a melting and holding furnace for melting and holding a molten metal such as aluminum, aluminum alloy, and non-ferrous metal (see, for example, Patent Document 1). The furnace body of a general melting and holding furnace is composed of a bottom wall and a peripheral wall or side wall extending in the vertical direction from the peripheral end of the bottom wall. The bottom wall and the side wall generally include, from the outside toward the inside in sequence, an iron outer wall (sheet iron), a heat insulating layer, a support layer, and a refractory layer (hereinafter, also referred to as a refractory or refractory material) as an inner lining material, and a molten metal storage portion for holding the molten metal is formed inside the refractory layer.

[0003] In such a melting and holding furnace, for the inner lining material, particularly the refractory layer in contact with the molten metal, precast blocks of refractory, refractory bricks, castables of unshaped refractories, etc. are used. The molten metal has the property of easily penetrating into the structure of these refractory layers.

[0004] For example, oxides may sometimes be generated in a molten aluminum alloy (hereinafter, also referred to as molten aluminum), and cracks (crazing) that are likely to cause furnace body damage may occur due to long-term use or rapid temperature changes. The molten aluminum penetrates into the cracks of the refractory layer, resulting in molten metal leakage (also referred to as liquid leakage), and the molten aluminum leaks outside the molten metal storage portion.

[0005] In order to prevent molten metal leakage, Patent Document 2 discloses a lining structure of a molten metal holding container, in which two or more recesses are arranged in a staggered manner on the inner surface of a permanent lining, and further, the inner surface of the permanent lining is covered with a mortar layer having a low longitudinal elastic modulus. By adopting such a structure, the following effects are shown: the strain generated on the inner surface of the permanent lining is dispersed to prevent the generation of cracks, and in addition, even if cracks are generated on the inner surface of the permanent lining, the molten metal leakage can be prevented by the mortar layer.

[0006] Prior Art Documents

[0007] Patent Documents

[0008] Patent Document 1: Japanese Patent No. 6644776 Gazette

[0009] Patent Document 2: Japanese Unexamined Patent Application Publication No. 2017-194236 Summary of the Invention

[0010] Technical Problem to be Solved by the Invention

[0011] As described above, Patent Document 2 shows a method for preventing molten metal leakage, but does not show measures for suppressing heat dissipation from the furnace body.

[0012] It should be noted that there are the following problems with respect to the heat dissipation from the furnace body. That is, in order to keep the molten metal at a certain temperature in the molten metal storage part, it is necessary to continuously operate heat sources such as an immersion heater and an immersion burner. However, in the past, due to the heat dissipation from the furnace body, energy such as electricity and gas more than required was supplied to the heat source, resulting in low efficiency. Furthermore, since the surface temperature of the furnace body and the atmospheric temperature around the furnace body are likely to rise, there may also be problems such as burns and other injuries caused by operators contacting the furnace body and deterioration of the working environment.

[0013] In addition, regarding the prevention of molten metal leakage, although there is actually a method of using a refractory material with a thickness of about 100 mm in the refractory layer to deal with it, after about 6 to 8 years from the start of using the furnace, damage caused by cracks in the furnace body may sometimes be found.

[0014] In addition, in the case of stopping continuous operation 2 to 4 times a year only for maintenance purposes, it is extremely difficult to prevent the molten metal from leaking to the outside, and it is necessary to focus on dealing with the disadvantages in terms of ensuring the safety of operators and reducing the heat of the molten metal on the operation surface.

[0015] Therefore, an object of the present invention is to provide a metal molten metal furnace that can prevent or suppress molten metal leakage and can suppress heat dissipation from the furnace body.

[0016] Means for Solving Technical Problems

[0017] The means for solving the above technical problems are as follows.

[0018] A metal molten metal furnace having an outer wall on its outer periphery and having a molten metal storage part for holding molten metal, characterized in that

[0019] Two or more inner lining layers are provided on the inner wall of the metal molten metal furnace forming the above-mentioned molten metal storage part,

[0020] Among the above-mentioned inner lining layers, a first inner lining layer forming a surface in contact with the above-mentioned molten metal is made of a refractory material,

[0021] Sealing materials are provided at at least two boundaries between the above-mentioned first inner lining layer and the above-mentioned outer wall,

[0022] The inner lining layer between the above-mentioned sealing materials is a heat insulating board containing at least silicon dioxide (SiO 2 )

[0023] Advantages of the Invention

[0024] According to the present invention, it is possible to prevent or suppress molten metal leakage and to suppress heat dissipation from the furnace body. Brief Description of the Drawings

[0025] Figure 1 It is a cross-sectional view of a metal molten bath furnace example.

[0026] Figure 2 It is used to illustrate Figure 1 the molten liquid leakage of part X.

[0027] Figure 3 It is a cross-sectional view of an example of the sealing material arrangement in the embodiment.

[0028] Figure 4 It is a rear view of an example of the braiding of the sealing material.

[0029] Figure 5 It is a rear view of an example of the braiding of the sealing material reinforced by reinforcing fibers.

[0030] Figure 6 It is a cross-sectional view of an example of the sealing material arrangement in another embodiment.

[0031] Figure 7 It is a cross-sectional view of an example of the sealing material arrangement in yet another embodiment.

[0032] Figure 8 It is a cross-sectional view of an example of the sealing material arrangement in still another embodiment.

[0033] Figure 9 It is a cross-sectional view of an example of the sealing material arrangement in different embodiments. Detailed Embodiment

[0034] Hereinafter, embodiments of the present invention will be described.

[0035] As Figure 1 shown, the metal molten bath furnace has an outer wall 1 on the outer peripheral portion, and two or more inner lining layers are provided on the inner wall forming the molten liquid storage portion 6 to hold the metal molten liquid M.

[0036] The inner lining layer is, for example, as Figure 1 shown, composed of a first inner lining layer 10, a second inner lining layer 20, and a third inner lining layer 30.

[0037] The first inner lining layer 10 forms the surface in contact with the metal molten liquid M such as aluminum or its alloy, and is composed of a refractory material. As the refractory material, for example, a low-cement castable mainly composed of alumina (Al 2 O 3 ) can be used. During construction, the water content rate is adjusted to 10% or less, and then it is dried to make the density 2500 - 3500 kg / m 3 of the refractory material. Regarding the second inner lining layer 20, the third inner lining layer 30, etc., they will be described in detail later.

[0038] As the metal molten bath furnace, various structures can be targeted.Figure 1 The structure shown is a molten metal holding furnace for low-pressure casting, and the details are as described below.

[0039] That is, it has a hot water outlet 2 at the upper part, and the hot water outlet 2 is composed of a cylindrical furnace duct 3. In addition, it has a gas supply port 4 and an exhaust port 5 at the upper part, and can supply and exhaust pressurized gas to and from the molten metal holding chamber.

[0040] Through a pressurizing device (not shown), a pressurized gas such as an inert gas like dry air, argon, nitrogen, etc. is sent into the molten metal holding chamber via the gas supply port 4. The molten metal surface is pressurized by the pressurized gas sent into the molten metal holding chamber, and the molten metal rises in the furnace duct 3 and is pressed into a cavity formed in a casting mold (not shown) via the hot water outlet 2.

[0041] After casting is completed, the supply of the pressurized gas from the gas supply port 4 is stopped, and the pressurized gas in the molten metal holding chamber is discharged from the exhaust port 5.

[0042] In such a molten metal furnace, as described above, in addition, as Figure 2 schematically shown (an example in the case of 4 layers of the inner lining), due to long-term use and sudden temperature changes, cracks (crazing) C that are prone to furnace body damage may occur, and molten metal, such as aluminum molten metal, may penetrate into the cracks of the refractory layer to cause molten metal leakage (also called liquid leakage). The outer wall 1 is, for example, an iron outer wall. In an extreme example, there is a situation where the aluminum molten metal that has penetrated the crack reaches the outer wall 1, and the outer wall 1 expands outward due to the heat of the aluminum molten metal. The flow example of molten metal leakage is shown by Figure 2 the dashed line.

[0043] Regarding this problem, in the Figure 3 embodiment shown, a sealing material 50 (first sealing material 50A) is provided between the first inner lining layer 10 and the second inner lining layer 20 on the outer wall side, and a sealing material 50 (second sealing material 50B) is also provided between the second inner lining layer 20 and the third inner lining layer 30 on the outer wall side. It should be noted that when two or more sealing materials 50 are provided, they are sequentially called the first sealing material 50A, the second sealing material 50B, the third sealing material 50C... from the inner wall side to the outer wall side.

[0044] As this sealing material 50, a sheet-shaped sealing material can be preferably used, especially a sheet with a thickness of 2 - 10 mm.

[0045] Moreover, the sealing material 50 is particularly preferably a sheet woven from at least one of ceramic fiber and bio-soluble ceramic fiber and at least one of glass fiber and stainless steel fiber.

[0046] The bio-soluble ceramic fibers used in the present invention are selected from the fibers in Category 0 (excluded substances for applications) of the restrictions of "EU Directive 97 / 69 / EC". Therefore, it is necessary to prove safety through one of the following 4 animal experiments according to NotaQ "Determination Criteria for Bio-soluble Fibers in the Body", or it is necessary to use fibers whose value obtained by subtracting twice the standard deviation from the length-weighted geometric mean fiber diameter exceeds 6 μm according to NotaR "Determination Criteria for Non-inhalable Fibers".

[0047] (1) In the in-vivo retention test based on short-term inhalation, fibers longer than 20 μm have a loading half-life of less than 10 days;

[0048] (2) In the in-vivo retention test based on short-term intratracheal injection, fibers longer than 20 μm have a loading half-life of less than 40 days;

[0049] (3) There is no evidence of excessive carcinogenicity due to intraperitoneal administration test;

[0050] (4) In the long-term inhalation test, there are no associated pathogenic or neoplastic changes.

[0051] If it is a bio-soluble ceramic fiber that has confirmed the above safety, there are no special restrictions on its manufacturing method, chemical composition, average fiber diameter or average fiber length. For example, bio-soluble asbestos can also be used.

[0052] Bio-soluble ceramic fibers containing oxides of alkali metals and alkaline earth metals (Na 2 O, K 2 O, CaO, MgO, BaO, etc.) with a content greater than 18% by mass can be used.

[0053] Alkaline earth metal silicate cotton such as silica-magnesium oxide-calcium oxide-based can also be used.

[0054] As ceramic fibers, man-made mineral fibers mainly composed of alumina (Al 2 O 3 ) and silica (SiO 2 ), namely amorphous refractory ceramic fibers (hereinafter referred to as RCF), which are mainly used at temperatures below 1400 °C, and alumina-based crystalline ceramic fibers used at temperatures higher than 1400 °C are known. The manufacturing methods, properties, and prices of these RCF and crystalline ceramic fibers are very different, and they are used separately according to their respective characteristics.

[0055] The temperature of the molten metal, especially aluminum or aluminum alloy, reaches 700 °C or higher. Therefore, it is preferred to reinforce at least one of the ceramic fibers and the bio-soluble ceramic fibers with at least one of glass fibers and stainless steel fibers.

[0056] In particular, from the aspect of heat resistance, it is preferable to reinforce at least by using stainless steel fibers.

[0057] As the sealing material 50, in order to form a sheet-shaped sealing material, particularly a sheet with a thickness of 2 to 10 mm, fiber filaments (fibers or strands) can be woven into a sheet. Regarding weaving, in addition to Figure 4 and Figure 5 the plain weave, twill weave, and satin weave shown, an appropriate weaving method can also be adopted.

[0058] And, as shown in Figure 5 , at least one reinforcing fiber 52 among glass fibers and stainless steel fibers can be woven into at least one of the first fibers 51A and 51B, which are ceramic fibers and bio-soluble ceramic fibers, in an appropriate manner. The reinforcing fiber 52 can also be assembled inside a strand for reinforcement. Moreover, the strand assembled with the reinforcing fiber can be woven in an appropriate manner to form a sheet-shaped sealing material.

[0059] As shown in Figure 6 , a sealing material 50 (second sealing material 50B) can also be provided between the third inner lining layer 30 and the fourth inner lining layer 40 closer to the outer wall 1 side than it.

[0060] Moreover, as shown in Figure 7 , a sealing material 50 (first sealing material 50A) can be provided between the first inner lining layer 10 and the second inner lining layer 20, a sealing material 50 (second sealing material 50B) can be provided between the second inner lining layer 20 and the third inner lining layer 30, and further a sealing material 50 (third sealing material 50C) can be provided between the third inner lining layer 30 and the fourth inner lining layer 40.

[0061] In the present invention, it is only necessary to provide the sealing material 50 at at least two boundaries between the first inner lining layer 10 and the outer wall 1. For example, as shown in Figure 8 , a sealing material 50 (first sealing material 50A) can be provided at the boundary between the second inner lining layer 20 and the third inner lining layer 30, and a sealing material 50 (second sealing material 50B) can be provided at the boundary between the third inner lining layer 30 and the fourth inner lining layer 40.

[0062] Furthermore, for example, as shown in Figure 9 , a sealing material 50 (first sealing material 50A) can be provided at the boundary between the first inner lining layer 10 and the second inner lining layer 20, and a sealing material 50 (second sealing material 50B) can be provided at the boundary between the second inner lining layer 20 and the outer wall 1.

[0063] In addition, after the sealing material 50 is disposed between the inner liner layers as described above, when the molten metal M is first placed in the molten metal storage portion, the heat of the molten metal M sometimes transfers through the first inner liner layer 10 to the sealing material 50, and the sealing material 50 emits a burnt smell. In order to suppress this odor, the sealing material 50 can be pre-fired.

[0064] It is worth mentioning that regarding molten metal leakage, in the past, the selection of the material of the first inner liner layer has been mainly concerned. However, it is inevitable to generate cracks in the first inner liner layer 10, and there is a risk of cracks occurring and residual leakage of the molten metal through these cracks.

[0065] The inventor of the present invention has completed the present invention on the premise that cracks are generated in the first inner liner layer 10, rather than focusing on the selection of the material of the first inner liner layer 10.

[0066] Even if the molten metal leaks through the cracks, as long as the leakage amount can be minimized, heat dissipation to the outside of the furnace can be reduced, and the direction of leakage can be controlled to suppress penetration into the outer wall, it is possible to achieve the ultimate goal of preventing the molten metal from leaking to the outer wall. In addition, heat dissipation from the furnace body can also be suppressed.

[0067] Using the sealing material according to the present invention, especially the heat-resistant (refractory) sealing material, brings the following advantages.

[0068] (1) It can withstand the molten metal temperature (for example, it can withstand 700 °C in molten aluminum).

[0069] (2) It will not contaminate the molten metal in the molten metal storage portion.

[0070] (3) It can reduce the heat of the leaked molten metal and can suppress the penetration of the leaked molten metal before it reaches the outer wall.

[0071] (4) It can control the direction in the case of molten metal leakage.

[0072] Normally, after the leaked molten metal descends along between the inner liner layers due to gravity, if it reaches the inner liner layer on the outer wall side that is horizontally arranged, it will expand in the horizontal direction. Depending on the situation, cracks may sometimes occur in the inner liner layer on the outer wall side that is horizontally arranged, and further through the cracks, the leakage of the molten metal will expand due to gravity, and the direction of leakage cannot be predicted.

[0073] If the sealing material 50 of the present invention is provided between the inner liner layers, since the sealing material 50 becomes a resistance, the leaked molten liquid is not easily lowered along between the inner liner layers due to gravity (i.e., the descending speed can be suppressed). Moreover, the leaked molten liquid flows along the fiber direction woven by the sealing material 50 and disperses, reducing the heat (heat capacity per unit area) of the leaked molten liquid during this period. And, since the first sealing material 50A and the material of the inner liner layer on the side of the molten liquid storage part 6 of the first sealing material 50A are different, heat conduction from the inner liner layer to the first sealing material 50A can also be suppressed. As a result, the amount of molten liquid flowing to the inner liner layer on the side of the outer wall 1 of the first sealing material 50A is sharply reduced. The amount of the leaked molten liquid varies according to the size of the above-mentioned crack, but by further providing the second sealing material 50B at any boundary between the inner liner layer adjacent to the outer wall 1 side of the first sealing material 50A and the outer wall 1, the amount of heat dissipated to the outside of the furnace is reduced (the material of the second sealing material 50B and the inner liner layer adjacent to the molten liquid storage part 6 side of the second sealing material 50B, and the material of the second sealing material 50B and the inner liner layer adjacent to the outer wall 1 side of the second sealing material 50B are different, so heat conduction between each inner liner layer and the second sealing material 50B can also be suppressed), the direction of leakage can be further controlled and penetration to the outer wall 1 can be suppressed. In addition, since two or more sealing materials 50 are provided, the molten liquid is not easily in direct contact with the inner liner layer on the outer wall 1 side, and cracks are not easily generated.

[0074] It should be noted that, in the case of controlling the leakage direction of the molten liquid in the present invention, specifically, it means suppressing the speed of the leaked molten liquid and controlling the penetration to the outer wall side by narrowing the space between the inner liner layers by using the sealing material 50 to increase the resistance.

[0075] In addition, as Figure 3 the second inner liner layer 20 of the embodiment shown, as the inner liner layer located at a position sandwiched between two or more sealing materials 50 in the thickness direction, it is preferable to use a heat insulating board containing at least silica (SiO 2 ). For example, it is preferable to use a ceramic fiber board, a board containing xonotlite, etc. If the inner liner layer sandwiched between the sealing materials 50, 50 is formed into such an inner liner layer, compared with the conventional second inner liner layer 20 (for example, a castable mainly composed of alumina (Al 2 O 3 ), during construction, the moisture content is adjusted to 45 to 65%, and then dried, and the density is 1000 to 1500 kg / m 3)In contrast, as described later, weight reduction can be achieved, that is, the density can be reduced, making it easier to handle. By reducing the density of the inner liner sandwiched between the sealing materials 50, 50, compared with the heat transfer ease of the first inner liner 10, the inner liner sandwiched between the sealing materials 50, 50 is less likely to transfer heat. That is, compared with the temperature drop from the molten liquid storage part 6 side of the first inner liner 10 to the outer wall 1 side, the temperature drop of the inner liner sandwiched between the sealing materials 50, 50 from the molten liquid storage part 6 side to the outer wall 1 side is greater. In this way, it is difficult to transfer heat from the inner liner sandwiched between the sealing materials 50, 50 to the outside (for example Figure 3 in the illustrated embodiment, to the layers such as the third inner liner 30 and the fourth inner liner 40 around it), and further, leakage of the molten liquid to the outside of the furnace can be prevented, and heat dissipation from the furnace body can be suppressed.

[0076] Furthermore, Figure 3 the density of the second inner liner 20 in the illustrated embodiment is preferably set to 250 kg / m 3 or more and less than 1000 kg / m 3 , and more preferably set to 350 - 450 kg / m 3 . If the above density is less than 250 kg / m 3 , the pressure of the molten metal M in the molten liquid storage part 6 is applied to the second inner liner 20 through the first inner liner 10 and the first sealing material 50A, so the molten metal is likely to penetrate the second inner liner 20. In addition, if it reaches 1000 kg / m 3 or more, the surface of the second inner liner 20 becomes hard, and it is difficult to fix it with a tap, which is one of the methods for fixing the sealing material 50 to the second inner liner 20. Further, if the density of the second inner liner 20 is 1000 kg / m 3 or more, the second inner liner 20 becomes heavy and is likely to break, which may make handling difficult, and it is easy to transfer heat, and the temperature drop from the molten liquid storage part 6 side to the outer wall 1 side cannot be obtained sufficiently.

[0077] As Figure 3 the second inner liner 20 in the illustrated embodiment, it is preferable to use a heat insulating board containing at least silica (SiO 2 ), that is, a ceramic fiber board, a tobermorite-containing board, etc. In this way, by using the inner liner sandwiched between the sealing materials 50, 50, heat dissipation from the furnace body can be suppressed.

[0078] In the above description, the second inner liner 20 in the Figure 3 illustrated embodiment has been described, but in the Figure 7 illustrated embodiment, the second inner liner 20, the third inner liner 30, in the Figure 8 illustrated embodiment, the third inner liner 30, in the Figure 9In the illustrated embodiment, the second inner liner 20 is equivalent to the inner liner sandwiched between the sheets 50, 50. Therefore, for these inner liners, it is preferable to use the above-mentioned respective plates and densities.

[0079] It should be noted that, as in the case of the third inner liner 30 and the fourth inner liner 40 in the illustrated embodiment, as the inner liner located outside the outermost sealing material 50 (in the Figure 3 embodiment is the second sealing material 50B), a fiber containing at least one of alumina (Al Figure 3 ) and silica (SiO 2 O 3 ), or a plate having a density of 150 to 250 kg / m 2 mainly composed of calcium silicate is used to ensure heat insulation and heat resistance. 3

[0080] In addition, in the illustrated example, the number of inner liners is set to a maximum of four layers (the fourth inner liner 40), but the number of inner liner layers can also be set to five layers or more. In this case, the sealing material 50 can also be provided below the fifth layer.

[0081] Therefore, in the conventional design concept, by the first inner liner 10 composed of a refractory material having a density of 2500 to 3500 kg / m 3 forming the surface in contact with the molten metal M such as aluminum or its alloy, and the second inner liner 20 composed of a refractory material having a density of 1000 to 1500 kg / m 3 , even if cracks occur in the first inner liner 10, the flow of the leaked molten liquid can be blocked or the flow rate can be suppressed. Furthermore, by the third inner liner 30 and the fourth inner liner 40 made of a fiber containing at least one of alumina (Al 2 O 3 ) and silica (SiO 2 ) or a plate having a density of 150 to 250 kg / m 3 mainly composed of calcium silicate, the temperature of the leaked molten liquid is reduced, thereby preventing the molten liquid from leaking outside the furnace.

[0082] However, the design concept of the present invention is that, by the first inner liner 10 composed of a refractory material having a density of 2500 to 3500 kg / m 3 forming the surface in contact with the molten metal M such as aluminum or its alloy, and a combination of an inner liner of a heat insulating plate containing at least silica (SiO 2 ) sandwiched between the sealing materials 50, 50, even if cracks occur in the first inner liner 10, at least silica (SiO 2 ​The inner lining layer of the heat insulating plate of (), while preventing the flow of the leaked molten liquid, makes it difficult for heat to transfer from the inner lining layer to the outside (for example, to the peripheral layers such as the third inner lining layer 30 and the fourth inner lining layer 40 in the Figure 3 embodiment), thereby preventing the molten liquid from leaking out of the furnace and suppressing heat dissipation from the furnace body.

[0083] As can be seen from the above, the inner lining layer of the heat insulating plate sandwiched between the sealing materials 50, 50 and containing at least silicon dioxide (SiO 2 ) not only prevents the flow of the leaked molten liquid but also suppresses heat dissipation from the furnace body. Therefore, a part of the support layer for preventing the flow of the leaked molten liquid provided in the past can be omitted, or the thickness can be reduced, and thus the thickness of each inner lining layer can be made thinner than in the past. Therefore, the metal molten liquid furnace itself can be miniaturized. That is, even when the capacity of the molten liquid storage part is the same as that of the past, the size of the metal molten liquid furnace itself can be reduced. Or, even when the capacity of the molten liquid storage part is a little more than that of the past, the size of the metal molten liquid furnace can be the same as or smaller than that of the past.

[0084] Industrial Applicability

[0085] As the molten liquid, it can also be other metal molten liquids besides aluminum or aluminum alloys.

[0086] It should be noted that the technical scope of the present invention is not limited to the above embodiments, and various modifications can be made without departing from the gist of the present invention. For example, the metal molten liquid furnace of the present invention can be used in a melting holding furnace, a melting furnace, a holding furnace, a low-pressure casting furnace, etc.

[0087] Explanation of Symbols

[0088] 1... outer wall, 10... first inner lining layer, 20... second inner lining layer, 30... third inner lining layer, 40... fourth inner lining layer, 50... sealing material, 50A... first sealing material, 50B... second sealing material, 50C... third sealing material, M... metal molten liquid.

Claims

1. A metal melt furnace has an outer wall on its outer periphery and includes a melt storage part for holding the metal melt. It is characterized in that two or more lining layers are provided on the inner wall of the metal melt furnace forming the melt storage part. Among the lining layers, the first lining layer forming the surface in contact with the metal melt is made of a refractory material. Sealing materials are provided between at least two selected from the group consisting of between the two or more lining layers and between the lining layer and the outer wall. The lining layer is sandwiched between two or more of the sealing materials. The sealing material is a sheet woven from at least one of ceramic fiber and bio-soluble ceramic fiber and at least one of glass fiber and stainless steel fiber. The metal melt furnace has a laminated structure with a lining layer sandwiched between the sealing materials, and the lining layer is a heat insulating board containing at least silicon dioxide SiO 2 .

2. The metal melt furnace according to claim 1, wherein The density of the inner liner layer between two or more of the above-mentioned sealing materials is 250 kg / m 3 or more and less than 1000 kg / m 3 .

3. The metal melt furnace according to claim 1 or 2, wherein The insulation board includes at least one of a ceramic fiber board and a board containing tobermorite.

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