JP5677912B2 - Lining structure of molten metal container - Google Patents

Description

The present invention relates to a lining structure for a molten metal container such as a ladle, a converter, or a kneading wheel used in an iron making process.

Molten metal containers such as ladle, converter, and kneading car have a plurality of types of refractory layers lined on an iron outer shell generally called an iron skin. The refractory layer is composed of a wear refractory on the operating surface side and a permanent refractory on the iron skin side (hereinafter also referred to as “perm brick”). The wear refractory is designed on the assumption that it will come into contact with the molten metal and wear out, and the life of the entire molten metal container is extended by carrying out repair or replacement work. On the other hand, since permanent bricks do not come into contact with molten metal or the like, they are basically not worn out and used over a long period of time.

In recent years, as one of the CO ₂ reduction measures, it has been required to suppress the heat radiated through the iron skin, and as one of the main measures, between the iron skin and the permanent brick or between the permanent brick and There is a method of placing a heat insulating material between the wear refractories. As this heat insulating material, a material having a low thermal conductivity (high heat insulating property) is required. For example, a fine material having a fine micropore structure of 100 nm or less using ultrafine powder having a particle size of 5 to 30 nm as a main raw material. A porous heat insulating material is known (for example, refer to Patent Document 1).
The microporous heat insulating material is characterized by exhibiting a low thermal conductivity of 0.02 to 0.05 W / (m · K), but when it comes into contact with water (liquid), the ultrafine powder aggregates to provide a heat insulating effect. It has a drawback that is greatly impaired. For example, when wear refractory wears out, and when an irregular refractory is added to the surface of the worn refractory and repaired, the moisture contained in the irregular refractory condenses on the inner surface of the iron skin at a low temperature, causing condensation. When the water droplets contacted with the fine porous heat insulating material, the heat insulating effect may be reduced.

As a countermeasure for preventing water absorption of a fine porous heat insulating material, for example, in Patent Document 2, an aerosil heat insulating material (fine porous heat insulating material), a permanent refractory (perm refractory) is provided on the inner side of the outer shell, from the iron skin side. ) When applying a refractory lining layer that has workpiece refractories (wear refractories) in this order, apply a water-resistant coating material to the aerosil insulation and / or permanent refractory, and then install the workpiece refractory The construction method of the refractory lining layer characterized by these is disclosed.

In addition, for example, in Patent Document 3, an ultrafine fumed oxide is used as a main raw material, and there are peaks in the pore diameter ranges of 0.01 to 0.1 μm, 0.1 to 10 μm, and 10 to 1000 μm, respectively. The raw material consisting of particles having a pore distribution is compressed and the resulting molded body is dipped in water in advance to absorb moisture, and then dried, whereby the pore size is in the range of 0.1 to 10 μm. A method for producing a high-performance heat insulating material (microporous heat insulating material) characterized by eliminating pores having peaks therein is disclosed.

JP 2000-104110 A JP 2010-236782 A JP 2011-001204 A

However, since the iron skin temperature of the molten metal container is usually about 300 to 400 ° C., the method described in Patent Document 2 in which the water-resistant coating material is applied to the microporous heat insulating material maintains long-term durability. Is difficult. Moreover, in the method of patent document 3 which absorbs a water | moisture content to a fine porous heat insulating material previously, since heat insulation falls at the time of making water absorb, high heat insulation cannot be exhibited.

The present invention has been made in view of such circumstances, and it is possible to prevent the condensation generated on the inner surface of the iron skin from coming into contact with the fine porous heat insulating material and to prevent the heat insulating effect of the fine porous heat insulating material from being reduced. It aims at providing the lining structure of a molten metal container.

In order to achieve the above object, in the lining structure of the molten metal container according to the present invention, the first heat insulating material is ceramic fiber, heat insulating mortar, or rock wool, and the first heat insulating layer made of the first heat insulating material. And a second heat insulating layer made of a second heat insulating material containing 20% by mass or more of ultrafine powder having a particle size of 0.3 μm or less, wherein the first heat insulating layer is a molten metal container rather than the second heat insulating layer. It is characterized by being arranged on the iron skin side.

Condensation occurs in the molten metal container on the inner surface of the iron skin, which has a lower temperature than other parts. On the other hand, a 2nd heat insulating material is a microporous heat insulating material which has the characteristic that an ultrafine powder will aggregate and a heat insulation effect will be impaired greatly when it contacts with water (liquid). In the present invention, by forming a water-absorbing heat insulating material (first heat insulating material) having water absorption between the iron skin and the microporous heat insulating material (second heat insulating material), dew condensation generated on the inner surface of the iron skin. Prevents contact with the fine porous heat insulating material, and maintains high heat insulating properties for a long period of time.

In the lining structure of the molten metal container according to the present invention, the thickness of the first heat insulating layer is preferably 0.2 mm or more.
If the thickness of the first heat insulating layer is less than 0.2 mm, moisture absorption by the first heat insulating layer is not sufficient, and a decrease in the thermal conductivity of the second heat insulating material is inevitable.

Moreover, since dew condensation occurs on the inner surface of the iron skin, it is preferable to dispose the first heat insulating layer close to the inner surface of the iron skin. Therefore, in the lining structure of the molten metal container according to the present invention, it is preferable that the first heat insulation layer is in contact with the inner surface of the iron skin, but a permanent refractory is disposed between the iron skin and the first heat insulation layer. It may be.

Moreover, in the lining structure of the molten metal container according to the present invention, a permanent refractory may be disposed on the working surface side of the second heat insulation layer, and between the first heat insulation layer and the second heat insulation layer. Permanent refractories may be arranged.

In the lining structure of the molten metal container according to the present invention, a water-absorbing heat insulating material having water absorption is arranged between the iron skin and the fine porous heat insulating material, so that condensation generated on the inner surface of the iron skin is generated in the fine porous heat insulating material. Without contact, it is possible to prevent a reduction in the heat insulating effect of the fine porous heat insulating material.

It is a schematic diagram of the lining structure of the molten metal container which concerns on the 1st Embodiment of this invention. It is a schematic diagram of the lining structure of the molten metal container which concerns on the 2nd Embodiment of this invention. It is a schematic diagram of the lining structure of the molten metal container which concerns on the 3rd Embodiment of this invention. It is a schematic sectional drawing of a test apparatus. It is a graph of the drying curve by an electric furnace.

Next, embodiments of the present invention will be described with reference to the accompanying drawings for understanding of the present invention.

[Lined Structure of Molten Metal Container According to First Embodiment]
FIG. 1 shows a lining structure of a molten metal container according to a first embodiment of the present invention.
In this Embodiment, it consists of the 1st heat insulation layer 12 which consists of a 1st heat insulating material, and the 2nd heat insulating material toward the working surface 16 (surface which contacts a molten metal) from the inner surface of the iron skin 11 of a molten metal container. It arrange | positions in order of the layer which consists of the 2nd heat insulation layer 13, the layer which consists of the permanent refractory 14, and the wear refractory 15.

The first heat insulating material is a water absorbing heat insulating material having heat resistance and water absorption, and has a function of absorbing moisture condensed on the inner surface of the iron skin 11. As the water absorbing heat insulating material, ceramic fiber, heat insulating mortar, rock wool or the like can be suitably used.
The thickness of the 1st heat insulation layer 12 shall be 0.2 mm or more in order to ensure water absorption. Note that the maximum thickness of the first heat insulating layer 12 is assumed to be about 50 mm.

The second heat insulating material is a microporous heat insulating material containing 20% by mass or more of ultrafine powder having a particle size of 0.3 μm or less. The fine porous heat insulating material forms a very fine space (micropore) such as about 100 nm or less between raw material particles to regulate the heat transfer of air, and in order to form such a space, Contains ultrafine powder with a diameter of 0.3 μm or less. As the ultrafine powder, it is desirable to use a raw material having a low intrinsic thermal conductivity such as fumed silica. In addition, when the amount of ultrafine powder is less than 20% by mass, the amount of micropores is small and the heat insulating effect is not sufficient, so that the amount is 20% by mass or more, and more preferably 50% by mass or more.
The thickness of the 2nd heat insulation layer 13 assumes about 1-20 mm.
As the second heat insulating material, Porextherm WDS (registered trademark) manufactured by Porextherm Dammstoffe GmbH, Microtherm manufactured by Nippon Microtherm Co., Ltd., or the like can be used.

When the microporous insulating material comes into contact with water (liquid), the ultrafine powder aggregates and the heat insulating effect is greatly impaired. Therefore, in this Embodiment, the 1st heat insulation layer 12 which consists of a 1st heat insulating material (water absorption heat insulating material) is iron-skin rather than the 2nd heat insulating layer 13 which consists of a 2nd heat insulating material (microporous heat insulating material). It arrange | positions at the 11 side and the dew condensation which generate | occur | produced on the iron skin 11 inner surface is made not to contact a fine porous heat insulating material.
Note that water vapor (gas) does not adversely affect the heat insulating effect of the fine porous heat insulating material.

The permanent refractory 14 may be either a regular refractory (brick) or an irregular refractory. The material of the permanent refractory 14 is not limited. For example, a refractory material made of rholite, zircon, clay, chamotte, high alumina, alumina, spinel, SiC, or a combination of two or more of these can be used.

The wear refractory 15 is an irregular refractory. There are no restrictions on the material of the amorphous refractories, and the main amorphous refractories are neutral alumina, high alumina, alumina-silica, alumina-spinel, alumina-magnesia, alumina-carbon, alumina A refractory material made of -SiC, alumina-SiC-carbon, or a combination thereof can be used.

[Lining structure of molten metal container according to second embodiment]
FIG. 2 shows a lining structure of a molten metal container according to the second embodiment of the present invention.
In the present embodiment, from the inner surface of the iron shell 11 of the molten metal container toward the working surface 16, the first heat insulating layer 12 made of the first heat insulating material, the layer made of the permanent refractory 14, and the second heat insulating material. The second heat insulating layer 13 and the layer composed of the wear refractory 15 are arranged in this order. That is, a layer made of the permanent refractory 14 is disposed between the first heat insulation layer 12 and the second heat insulation layer 13.

[Lining structure of molten metal container according to third embodiment]
FIG. 3 shows a lining structure of a molten metal container according to the third embodiment of the present invention.
In the present embodiment, from the inner surface of the iron skin 11 of the molten metal container toward the working surface 16, the layer made of the permanent refractory 14, the first heat insulating layer 12 made of the first heat insulating material, and the second heat insulating material. The second heat insulating layer 13 and the layer composed of the wear refractory 15 are arranged in this order. That is, a layer made of the permanent refractory 14 is disposed between the iron skin 11 and the first heat insulating layer 12.

Although the embodiments of the present invention have been described above, the present invention is not limited to the configurations described in the above-described embodiments, and is considered within the scope of the matters described in the claims. Other embodiments and modifications are also included. For example, any two or all of the first to third embodiments may be used in combination. That is, the layer made of the permanent refractory may be two or three layers.

The drying test of the lining material implemented in order to verify the effect of this invention is demonstrated. In this test, it is assumed that the wear refractory is worn by repeated operations, and a repair material made of an irregular refractory is added to the surface of the worn wear refractory. When the repair material is dried, moisture contained in the repair material is condensed on the inner surface of the iron skin having a low temperature.

FIG. 4 shows a schematic sectional view of the test apparatus. The test apparatus is schematically configured from an electric furnace 22 for heating the test body 20 and a test body 20 attached to an opening 22 a provided in the electric furnace 22.
The test body 20 is composed of an iron box 18 and a lining material inserted into the iron box 18.

In the iron box 18, one end surface facing the opening 22 a of the electric furnace 22 is an opening surface, and a steam hole 18 a is formed in the other end surface (corresponding to the iron skin 11) facing the one end surface. . Further, the entire side wall is covered with the heat insulating material 21 so that heat does not escape from the side wall formed at the peripheral edge of the other end surface.

The lining material charged in the iron box 18 is composed of a plurality of layers. FIG. 4 shows the lining configuration of the first to eighth embodiments. That is, in Examples 1 to 8, from the other end surface of the iron box 18 toward the one end surface, the first heat insulating layer 12 made of the first heat insulating material and the second heat insulating layer 13 made of the second heat insulating material. A layer made of the permanent perm brick 14a (perm refractory 14), a layer made of the semi-perm brick 14b (perm refractory 14), a layer made of the wear refractory 15 and a layer made of the repair material 17 are formed in this order. . Further, in Comparative Example 1, the first heat insulating layer 12 is not provided in the above-described configuration, and in Example 9, a layer made of the permanent refractory 14 is disposed between the first heat insulating layer 12 and the second heat insulating layer 13. 10, a layer made of the permanent refractory 14 is disposed between the other end face of the iron box 18 and the first heat insulating layer 12.

The materials and thicknesses of the first heat insulation layer 12 and the second heat insulation layer 13 are as shown in Table 1. “WDS” in the table refers to Porextherm WDS manufactured by Porextherm Dammstoffe GmbH.
The material of the permanent brick 14a is rholite refractory brick, the thickness is 65 mm, and the material of the semi-perm brick 14b is a high Al ₂ O ₃ refractory brick, the thickness is 65 mm.
The material of the wear refractory 15 is Al ₂ O ₃ —MgO quality amorphous refractory, the thickness is 50 mm, the material of the repair material 17 is Al ₂ O ₃ —MgO quality amorphous refractory, the thickness is 80 mm, and the moisture content is 7 mass. %.

When the test body 20 is heated and dried using the electric furnace 22, the moisture contained in the repair material 17 evaporates and moves to the other end surface side of the iron box 18. Then, water vapor is released into the atmosphere from a vapor hole 18a provided on the other end surface of the iron box 18, and condensation occurs on the inner side of the other end surface of the iron box 18 in the cooling process after drying. The condensed moisture is absorbed by the first heat insulating layer 12 made of the first heat insulating material (water absorbing heat insulating material).

A drying curve by the electric furnace 22 is shown in FIG. The vertical axis in FIG. 5 is the temperature in the electric furnace 22, and the horizontal axis is the elapsed time. While measuring the heat conductivity of the 2nd heat insulating material before a drying test previously, the heat conductivity of the 2nd heat insulating material after drying the test body 20 according to the drying curve of FIG. 5 was measured. For the measurement of the thermal conductivity, a thermal conductivity measuring device QTM-D3 manufactured by Kyoto Electronics Industry Co., Ltd. was used (the thermal conductivity of the second heat insulating material after the test / the second heat insulating material before the test). Each test body was evaluated by a thermal conductivity index represented by (thermal conductivity × 100). Specifically, the thermal conductivity index is less than 110 as “◯”, 110 or more and less than 140 as “Δ”, and 140 or more as “x”, and the change in the thermal conductivity of the second heat insulating material before and after the drying test is changed. Small ones were good.

The following can be seen from the table.
(1) By comparing Examples 1 to 3 with Comparative Example 1, it can be seen that when the first heat insulating layer 12 made of the first heat insulating material (water absorbing heat insulating material) is provided, the heat insulating effect is good.
(2) By comparing Examples 4 to 6, when the thickness of the first heat insulation layer 12 is 0.1 mm, the heat insulation effect is greater than when the thickness of the first heat insulation layer 12 is 0.2 mm or more. It turns out that it falls. Further, by comparing Examples 5, 7, and 8, it can be seen that any of ceramic fiber, heat insulating mortar, and rock wool can be used as the first heat insulating material.
(3) By comparing Examples 1, 9, and 10, it can be seen that the heat insulating effect is good regardless of the position of the permanent refractory 14.

11: Iron skin, 12: 1st heat insulation layer, 13: 2nd heat insulation layer, 14: Perm refractory, 14a: This perm brick, 14b: Semi-perm brick, 15: Wear refractory, 16: Working surface, 17: Repair material, 18: iron box, 18a: steam hole, 20: specimen, 21: heat insulating material, 22: electric furnace, 22a: opening

Claims (6)

The first heat insulating material is ceramic fiber, heat insulating mortar, or rock wool, and contains a first heat insulating layer made of the first heat insulating material and 20% by mass or more of ultrafine powder having a particle size of 0.3 μm or less. A second heat insulating layer made of two heat insulating materials,
A lining structure for a molten metal container, wherein the first heat insulating layer is disposed closer to the iron skin of the molten metal container than the second heat insulating layer. In the lining structure of the molten metal container according to claim 1 Symbol placement, the lining structure of the molten metal container thickness of the first insulation layer is 0.2mm or more. The lining structure of the molten metal container according to claim 1 or 2 , wherein the first heat insulating layer is in contact with an inner surface of the iron skin. The lining structure for a molten metal container according to claim 1 or 2 , wherein a permanent refractory is disposed between the iron skin and the first heat insulating layer. The lining structure of the molten metal container according to any one of claims 1 to 4 , wherein a permanent refractory is disposed on an operating surface side of the second heat insulating layer. The lining structure of the molten metal container according to any one of claims 1 to 5 , wherein a permanent refractory is disposed between the first heat insulating layer and the second heat insulating layer.

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