JP2011105986A - Refractory-lining structure of vessel for iron-making - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a refractory-lining structure of a vessel for iron-making, which is easy in working, can reduce working man-days and also can exhibit a thermal-insulating effect for a long period of time. <P>SOLUTION: In the refractory-lining structure of the vessel 1 for iron-making, the molten iron received from a blast furnace is held, the held molten iron is conveyed, or the held molten iron is subjected to a refining treatment. The refractory-lining structure comprises an iron-shell 2, a permanent-refractory layer 3 and a working-refractory layer 4 in this order from the outside of the vessel for iron-making, and a thermal-insulating material 5, whose compression strength is more than the ferrostatic pressure generated when holding the molten iron in the vessel for iron-making is arranged between the iron-shell and the permanent-refractory layer. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a refractory lining structure for a steelmaking vessel for receiving and holding hot metal discharged from a blast furnace, transporting the held hot metal, or performing a refining process on the held hot metal.

  In today's iron making process, the hot metal produced in the blast furnace and discharged from the blast furnace is received in a vessel represented by a topped car or hot metal ladle and transported to the next steel making process. Moreover, the molten steel melted in the converter or electric furnace in the steel making process is poured into a container such as a ladle and transported to the next process such as the secondary refining process or the continuous casting process. These iron-making containers generally have a lining structure formed of three layers of a workpiece refractory layer, a permanent refractory layer, and an iron skin in order from the working surface (contact surface with the molten metal) side. Both the workpiece refractory layer and the permanent refractory layer are formed of molded bricks (standard refractory) or amorphous refractories. When the workpiece refractory layers are formed of molded bricks, they are also called workpiece brick layers and permanent brick layers. In the present invention, containers for receiving hot metal and molten steel are collectively referred to as iron-making containers.

  When the hot metal or molten steel is transported to the next process, if the elapsed time (hereinafter referred to as “lead time”) becomes longer, the heat of the molten iron or molten steel is transferred to the refractory layer and the amount of heat released from the iron skin to the outside air is reduced. The problem arises that the temperature drop of the hot metal or molten steel increases. This increase in temperature drop causes an increase in the basic unit of heat sources such as ferrosilicon in the converter, and is therefore an important development issue from the viewpoint of rationalizing the cost of manufacturing steel products. Further, when the lead time is long, the temperature of the outermost iron shell increases, which may cause creep deformation or cracking of the iron shell. Therefore, as one of means for solving these problems, several techniques relating to heat insulation in the lining structure of the iron making container have been proposed.

  For example, in Patent Document 1, in a ladle in which a heat insulation board and a work brick layer are constructed in this order on an iron skin, a heat insulation lining in which a heat insulation brick such as a raw stone brick is provided between the heat insulation board and the work brick layer. A structure has been proposed. In particular, the thickness of the heat insulating brick layer is preferably 60 mm or more, and the thickness of the work brick layer is preferably 30 mm or less.

  However, when the technique described in Patent Document 1 is applied to a hot metal ladle that receives hot metal, there is a problem that the thickness of the heat insulating brick is large and the volume of the hot metal pan is reduced. Moreover, since the thickness of the heat insulating brick is large, the temperature gradient in the heat insulating brick is increased, and there is a possibility that a crack occurs in the heat insulating brick and the refractory life is shortened. Furthermore, when the thickness of the work brick layer is set to 30 mm or less, the operating surface side temperature of the heat insulating brick becomes high, and accordingly, there is a concern that the heat transfer amount is increased accordingly and the heat insulating performance is consequently lowered. .

  On the other hand, in patent document 2 and patent document 3, the heat insulating material which prescribed | regulated the range of thermal conductivity is arrange | positioned between a permanent refractory layer and an iron skin, and a workpiece | work refractory layer, permanent refractory from the working surface side. A lining structure of an iron making container having a four-layer structure composed of a physical layer, a heat insulating material, and an iron skin has been proposed. In particular, it is desirable that the heat insulating material has a thickness of 30 mm or less and has pores of 3 to 100 nm.

  At first glance, the techniques disclosed in Patent Document 2 and Patent Document 3 seem to obtain a heat insulating effect. However, when the techniques disclosed in Patent Document 2 and Patent Document 3 are applied in a hot metal ladle, depending on the lining thickness of each part, there is a possibility of exceeding the application temperature range of the heat insulating material, in order to obtain a heat insulating effect over a long period of time. Is not enough technology. That is, the heat insulating material is lower in heat resistance than a general refractory, and usually about 1000 ° C. is the upper limit temperature for using the heat insulating material, and the heat insulating material is deteriorated at a temperature higher than that to deteriorate the heat insulating performance. Furthermore, when a heat insulating material having pores is used, the strength is reduced, and the heat insulating performance is impaired due to compression during use.

  As a countermeasure for solving the problems of Patent Document 2 and Patent Document 3, Patent Document 4 proposes a technique of disposing a protective plate between a workpiece refractory layer and a permanent refractory layer. However, this method has a problem that the construction cost of the refractory increases because the number of steps for constructing the protective plate increases during the construction of the refractory. In addition, the protective plate may burn and disappear during drying and heating, and the working environment may be deteriorated due to fuming accompanying the burning and disappearance of the protective plate in the refractory drying process.

JP 2004-50256 A JP 2000-104110 A JP 2000-226611 A JP 2003-42667 A

  To insulate the lining structure of a steel container such as a hot metal ladle to reduce the molten metal temperature drop and suppress the deformation of the iron skin, the position of the heat insulating material, the number of refractory layers, and the thickness In addition, it is necessary to have a refractory lining structure that can sufficiently reduce the number of construction steps with sufficient consideration of the material. If the above prior art is verified from these viewpoints, there are still many points to be improved.

  The present invention has been made to solve the above-mentioned problems, and the object of the present invention is to receive and hold the hot metal discharged from the blast furnace, transport the held hot metal, or refining the held hot metal. In the refractory lining structure of the iron making container for carrying out the refractory of the iron making container that is easy to construct and can reduce the number of construction man-hours and can sufficiently exhibit the heat insulation effect over a long period of time. It is to provide a lining structure.

  The refractory lining structure for a steelmaking container according to the first aspect of the present invention for solving the above problems is to receive and hold hot metal discharged from a blast furnace and transport the held hot metal or refining the held hot metal. A refractory lining structure for an iron making container for carrying out the above, having an iron skin, a permanent refractory layer, and a workpiece refractory layer in this order from the outside of the iron making container, the iron skin and the permanent refractory Between the layers, a heat insulating material having a compressive strength equal to or higher than a static iron pressure value generated when the hot metal is held in the iron making container is characterized.

  The refractory lining structure of the iron making container according to the second invention is the molded brick according to the first invention, wherein the permanent refractory layer has a thickness of 30 mm or more and 65 mm or less at the side wall and bottom of the iron making container. It consists of two or more brick layers.

  A refractory lining structure for a steelmaking container according to a third invention is characterized in that, in the first or second invention, the brick structure of the permanent refractory layer is a joint structure.

  The refractory lining structure for an iron making container according to a fourth aspect of the present invention is the refractory lining structure according to any one of the first to third aspects, wherein the workpiece refractory layer has a construction thickness of 100 mm or more.

  A refractory lining structure for a steelmaking container according to a fifth invention is any one of the first to fourth inventions, wherein the heat insulating material has a thickness of 5 mm or less.

  In the refractory lining structure for a steelmaking container according to the sixth invention, in any one of the first to fifth inventions, the heat insulating material has a thermal conductivity of 0.15 W / (m · K) or less. It is characterized by that.

  According to a seventh aspect of the present invention, there is provided the refractory lining structure for an iron making container according to any one of the first to sixth aspects, wherein the workpiece refractory layer has a thermal conductivity of 35 W / (m · K) or less. Or it consists of an indefinite shape refractory.

According to the present invention, the installation position of the heat insulating material is optimized and the refractory lining structure of the iron making container such as a hot metal ladle is heat-insulated using a high-strength heat insulating material, so that the construction is easy. A sufficient heat insulating effect can be obtained over a long period of time without increasing the number of construction steps. As a result, it is possible to create a thermal margin for hot metal over a long period of time, reduce the basic unit of heat generating agents such as ferrosilicon in the converter, and increase the amount of iron scrap used by creating a thermal margin. Therefore, it is possible to reduce the reducing agent ratio in the blast furnace, that is, to reduce CO ₂ , and an iron-making process considering the environment becomes possible. Furthermore, since the temperature of the iron skin is reduced, cracks and deformations in the iron skin are suppressed, and a long life of the iron making container is realized.

It is a figure which shows the investigation result of the relationship between the compressive strength of a heat insulating material, and temperature. It is the schematic which shows the model structure of a refractory lining. It is a figure which shows the calculation result of the heat insulation effect when changing the construction position of a heat insulating material. It is a figure which shows the calculation result of the temperature change by the side surface of a heat insulating material when changing the thickness of a heat insulating material. It is the schematic of the experimental apparatus for confirming the heat insulation effect. It is a figure which shows the measurement result of the heat flux obtained by the experimental apparatus. It is the schematic which shows the example of the hot metal ladle constructed with the lining structure which concerns on this invention.

  Hereinafter, the present invention will be described in detail.

  In the case of a ladle-shaped iron-making container represented by a hot metal ladle, the heat removal mode is (a) heat radiation from the iron skin through the refractory layer to the outside air, and (b) heat radiation from the opening to the outside air. There are two ways. Any of these heat radiations is considered to be removed by two types of heat transfer mechanisms by radiation heat transfer from the heat dissipation surface to the outside air and convection heat transfer from the heat dissipation surface.

The following equation (1) shows the amount of heat released by radiant heat transfer. However, in (1), Q _R is the heat radiation amount by radiation heat transfer (J / sec), sigma is the Stefan - Boltzmann constant ^{(= 5.67 × 10 -8 J /} (m 2 · sec · K 4)) , epsilon is emissivity (-), S _n is the heat transfer surface area (m ^2), T is the object surface temperature (K), T ₀ is the ambient air temperature (K).

The following formula (2) shows the amount of heat released by convective heat transfer. However, in (2), Q _C is the heat radiation amount by the convective heat transfer (J / sec), h _C is the natural convection heat transfer coefficient ^{(J / (m 2 · sec} · K)), S n is the heat transfer surface Area (m ² ), T is the object surface temperature (K), and T ₀ is the outside air temperature (K).

  The present inventors investigated the amount of heat removal from the hot metal ladle and its breakdown as a preliminary study. The results are shown in Table 1. As shown in Table 1, it was found that “heat removal from the iron skin” in (a) was about 40% of the whole, and “heat radiation from the opening” in (b) was about 60% of the whole. did.

  As a result of this investigation, heat removal from the iron skin is 40%, so it was confirmed that the heat removal amount by heat insulation of the lining structure can be sufficiently reduced. Therefore, the present inventors conducted various studies on the optimum lining of the hot metal ladle.

First, the compressive strength of the heat insulating material was investigated. It was found from the measurement results that when the stress-strain curve of the heat insulating material was measured using a compression tester, the compressive strength increased monotonously as the amount of strain increased. Therefore, in the present invention, the compressive stress value when a strain amount of 10% is applied is defined as the compressive strength of the heat insulating material. FIG. 1 shows the results of an investigation of the relationship between the compressive strength of the heat insulating material A and the heat insulating material B (= compressive stress value when a strain amount of 10% is applied) and the temperature. The heat insulating material A and the heat insulating material B are both Al ₂ O ₃ —SiO ₂ type materials. Moreover, in FIG. 1, the static iron pressure (about 0.36 MPa) of the hot metal in the hot metal ladle bottom part when hot metal is accommodated in the hot metal hot pot.

  As shown in FIG. 1, both the heat insulating material A and the heat insulating material B increase in compressive strength as the temperature increases, but in the heat insulating material A, the compressive strength of the heat insulating material decreases conversely at a high temperature of 800 ° C. or higher. It became below the static iron pressure value. On the other hand, the heat insulating material B always has a compressive strength equal to or higher than the static iron pressure value, and showed a characteristic that the strength increases as the temperature increases. As described above, it was confirmed that not only the compressive strength differs depending on the material and type of the heat insulating material, but also the relationship between the compressive strength and the temperature differs.

  The static iron pressure value varies depending on the shape and size of the iron-making vessel such as hot metal ladle and topped car, but if the strength of the insulation is insufficient than the static iron pressure value, the mass load of the contained molten iron over a long period of time Due to this, a decrease in thickness occurs due to compression of the heat insulating material. When the thickness of the heat insulating material is reduced, the heat conductivity of the heat insulating material is increased and the heat insulating effect of the heat insulating material is deteriorated. Therefore, the heat insulating material is received in at least the steel container used in the use environment. It was found that it was necessary to have a compressive strength higher than the static iron pressure value depending on the amount or the amount of steel received. It should be noted that the upper limit of 1000 ° C. is sufficient as the use environment of the heat insulating material.

  Next, the construction site of the heat insulating material was examined comprehensively using unsteady heat transfer calculation. A schematic diagram of the model structure of the refractory lining used for the calculation is shown in FIG. Here, the permanent refractory layer 3 was assumed to be a two-layered brick. The construction parts of the heat insulating material are respectively located between the workpiece refractory layer 4 and the permanent refractory layer 3, between the two layers of the formed brick 3a and the molded brick 3b constituting the permanent refractory layer 3, and the permanent refractory layer. The amount of heat removal (amount of temperature drop of molten metal) when the thickness of the heat insulating material was changed between 3 and the iron skin 2 was calculated. In FIG. 2, the two-layered bricks constituting the permanent refractory layer 3 are indicated by 3 a and 3 b, while the heat insulating material is not indicated. Further, the mark ● shown in FIG. 2 represents the temperature distribution.

  The calculation results are shown in FIG. The vertical axis in FIG. 3 shows the rise in the hot metal temperature when the heat insulating material is arranged as a reference, when the heat insulating material is not installed as a negative value, and the larger the negative value, the greater the heat insulating effect. Is shown. As shown in FIG. 3, when the heat insulating material is installed in any of the above three locations, the amount of heat removal is greatest when the heat insulating material is constructed between the workpiece refractory layer 4 and the permanent refractory layer 3, On the other hand, it was found that when the heat insulating material was applied between the permanent refractory layer 3 and the iron shell 2, the amount of heat removal was most suppressed. In other words, it was found that the heat insulation effect is the highest when a heat insulating material is applied between the permanent refractory layer 3 and the iron skin 2. It has also been found that when the thickness of the heat insulating material exceeds 5 mm, the rate of change in heat removal becomes small.

  Further, FIG. 4 shows the result of calculating the temperature change on the inner surface side (= operating surface side) of the heat insulating material when the thickness of the heat insulating material is changed when the heat insulating material is applied to each of the above-described parts. As shown in FIG. 4, even when the heat insulating effect is the highest when the heat insulating material is applied between the permanent refractory layer 3 and the iron skin 2, the thickness of the heat insulating material exceeds 5 mm. The inner temperature was found to exceed 1000 ° C. Moreover, when the thickness of the heat insulating material exceeded 5 mm, it turned out that the ratio of the temperature change with respect to heat insulating material thickness falls.

  From the results of FIGS. 3 and 4, it has been found that even if the thickness of the heat insulating material is larger than 5 mm, the change in the heat removal amount does not simply increase, and the rate of change in the heat removal amount gradually stagnates. In addition, since the heat insulation of the commercially available heat insulating material may shrink due to the heat of the heat insulating material itself and the thermal conductivity may increase at a high temperature exceeding 1000 ° C., the temperature of the heat insulating material may be avoided in order to avoid the quality change of the heat insulating material. Is preferably suppressed to 1000 ° C. or lower.

  Further, in the hot metal ladle, the number of layers of the molded brick of the permanent refractory layer 3 is 1, the case of 2 layers, the case of 2 layers, the back side of the permanent refractory layer 3 when changed to the case of 3 layers, that is, the heat insulating material. As a result of investigating the temperature on the inner surface side, it was found that when the permanent refractory layer 3 was formed of two or more molded bricks, the temperature was low. This is because a temperature gap is generated due to the presence of an adhesive surface such as mortar between two molded bricks. Even in the case of so-called “colored joints” where there is no mortar, a temperature gap due to the air layer is generated, so it is effective to use the permanent refractory layer 3 as two or more molded bricks. Moreover, making the permanent refractory layer 3 into two or more shaped bricks is also effective in forming a heat stress absorption margin due to heating of the bricks. Furthermore, when hot metal pretreatment such as desulfurization treatment (KR method) is performed using a hot metal ladle with a mechanical stirring desulfurization facility, centrifugal force is generated in the hot metal by the rotating stirring flow, but two permanent refractory layers 3 are formed. By using the above-described molded brick, it is effective for reducing the mechanical load on the refractory and the heat insulating material due to the centrifugal force.

  Furthermore, when the heat radiation amount when the thickness of the two-layered bricks constituting the permanent refractory layer 3 is changed and the temperature on the inner surface of the heat insulating material are investigated, the heat radiation amount is low when the thickness is 30 mm or more. It has been found. Therefore, in order to obtain a sufficient heat insulating performance, it is preferable to secure a thickness of the formed brick of 30 mm or more. On the other hand, the upper limit is not particularly defined from the viewpoint of heat insulation, but is preferably 65 mm or less from the viewpoint of securing the volume of the container and workability. In addition, various bricks, such as a MgO quality brick, a high alumina quality brick, a rhostone brick, can be used for the material of the forming brick (it is also called a permanent brick) which comprises the permanent refractory layer 3. FIG.

  In the furnace bottom, it is desirable that the permanent refractory layer 3 is formed of three or more layers of bricks from the viewpoints of preventing leakage, further heat retention, and mitigating generated stress due to hot metal. Even in this case, the brick thickness per layer is preferably 30 mm or more and 65 mm or less.

  Moreover, the lining structure of two or more molded bricks in the permanent refractory layer 3 is not “joint joints (where the joints of the two layers of permanent bricks are the same location)”, but “joint joints”. (It is desirable that the joints of the two-layer permanent bricks are different locations). In the through-joint structure, stress concentrates on the joint, causing cracks (mechanical spalling), and when hot metal or molten steel enters the refractory from the crack, there is a risk of reaching the iron skin. On the other hand, by adopting a joint structure, it is possible to alleviate the load stress due to the thermal stress and the centrifugal force of the molten iron during mechanical stirring. In the joint structure, even if cracks occur in the refractory, even if hot metal or molten steel enters the refractory from the crack, the path to the iron shell increases, so the intrusion is stopped halfway. It is possible to prevent steel leakage and leakage. Similarly, the stacked structure between the workpiece refractory layer and the permanent refractory layer is preferably a joint.

  The present inventors conducted experiments in a laboratory in order to verify the above calculation results. A schematic diagram of the experimental apparatus is shown in FIG. A lining layer simulating the refractory lining of the actual hot metal ladle is installed on the side wall of the electric resistance heating furnace, and the internal temperature of the electric resistance heating furnace is maintained at a constant temperature (= 1300 ° C) using a thermocouple and heat flow sensor. Then, the heat flux on the surface of the iron skin was measured. The heat insulating materials are between the workpiece refractory layer 4 and the permanent refractory layer 3, between the two formed bricks 3a and 3b of the permanent refractory layer 3, and between the permanent refractory layer 3 and the iron skin 2 respectively. The thickness of the heat insulating material was changed to 1 mm, 3 mm, 5 mm, 7 mm, and 10 mm, respectively.

  The measurement result of the heat flux is shown in FIG. Under the condition that the heat insulating material was applied between the permanent refractory layer 3 and the iron shell 2, the heat flux was the lowest. In each condition, the heat flux became lower as the heat insulation thickness increased up to 5 mm, but no increase in the heat flux was observed even when the thickness changed from 5 mm to 10 mm. From this experimental result, the validity of the calculation result was confirmed.

  The present invention was made on the basis of the above examination results, and the refractory lining structure of the iron making container according to the invention receives and holds the hot metal discharged from the blast furnace and conveys or holds the held hot metal. The refractory lining structure of the iron making container for carrying out the refining process, from the outside of the iron making container, having an iron skin, a permanent refractory layer, a workpiece refractory layer in this order, the iron skin and the Between the permanent refractory layer, a heat insulating material having a compressive strength equal to or higher than the static iron pressure value generated when the hot metal is held in the iron making container is characterized.

  Regarding the thickness of the workpiece refractory layer, it is preferable to ensure 100 mm or more. Usually, the hot metal ladle is used for a long time, and the workpiece refractory layer is gradually damaged by reaction with spalling and slag. In order to reduce the number of days and costs for refractory re-covering, we want to limit the work refractory layer re-sending at least once every six months. Although the workpiece refractory layer is damaged by long-term use of the hot metal ladle, the thickness of the workpiece refractory layer is to ensure a minimum of 30 mm even when the thickness is reduced to ¼ after half a year from the start of operation. It is preferable to secure a thickness of 100 mm or more during construction.

The workpiece refractory layer may be either a molded brick or an irregular refractory, but the molded brick or the irregular refractory constituting the workpiece refractory layer should have a low thermal conductivity as much as possible from the viewpoint of heat insulation. It should be used, and the upper limit of the thermal conductivity is preferably 35 W / (m · K) or less. This is because in a refractory having a thermal conductivity exceeding 35 W / (m · K), the temperature on the inner surface of the heat insulating material exceeds 1000 ° C., and the performance of the heat insulating material may be deteriorated. In addition, as materials of the refractory constituting the workpiece refractory layer, various materials such as MgO-C brick, Al ₂ O ₃ -C system, Al ₂ O ₃ -SiC system, Al ₂ O ₃ -SiC-C system brick, etc. Brick can be used.

As the heat insulating material used in the present invention, the material can be various materials such as SiO ₂ and Al ₂ O ₃ and is not particularly limited. It is necessary to use one higher than the static iron pressure. For example, a heat insulating material to which silicon carbide (SiC), titanium oxide, or the like is added may be used. Moreover, you may use the heat insulating material which mixed the fiber fiber etc. and ensured intensity | strength.

  The thermal conductivity of the heat insulating material is desirably 0.15 W / (m · K) or less from the viewpoint of obtaining the effect of reducing the heat removal amount. If it exceeds 0.15 W / (m · K), the amount of heat release increases and the expected heat insulating effect cannot be obtained. In addition, since the heat insulating material itself contracts at a high temperature exceeding 1000 ° C. and the thermal conductivity may increase at a high temperature exceeding 1000 ° C., the use temperature is preferably 1000 ° C. or lower. Regarding the construction of the heat insulating material, it is desirable to adopt a construction method that avoids moisture absorption into the heat insulating material.

  According to the present invention having such a configuration, the installation position of the heat insulating material is optimized, and the refractory lining structure of the iron making container such as a hot metal ladle is heat-insulated using a heat insulating material having high strength. It is easy to obtain a sufficient heat insulating effect over a long period of time without increasing the number of construction steps. In particular, when the thickness of the heat insulating material is 5 mm or less, the heat insulating material is not exposed to a temperature exceeding 1000 ° C., and the heat insulating material is prevented from being deteriorated, and a high heat insulating effect can be obtained over a long period of time. It becomes possible.

  As a steelmaking container, the hot metal ladle shown in FIG. 7 having a heat size of 300 tons is taken up, and a work refractory layer, a permanent refractory layer, and a heat insulating material are attached to the side wall and bottom of the hot metal pan by various construction methods. It was constructed. Here, the static iron pressure at the bottom of the hot metal ladle calculated when the heat size is 300 tons is 0.4 MPa. Table 2 shows the construction conditions of the inventive example and the comparative example. In FIG. 7, reference numeral 1 is a hot metal ladle, 2 is an iron skin, 3 is a permanent refractory layer, 4 is a workpiece refractory layer, 5 is a heat insulating material, and FIG. 7 shows an example of the present invention example 1. ing.

In Example 1 of the present invention, a heat insulating material having a material of Al ₂ O ₃ —SiO ₂ , a compressive strength of 0.6 MPa and 1.2 MPa at room temperature and 1000 ° C., and a thickness of 3 mm was used. This heat insulating material was applied between the permanent refractory layer and the iron skin. The heat conductivity of the heat insulating material is 0.15 W / (m · K). The permanent refractory layer was one layer of molded brick, and its thickness was 60 mm. A work refractory layer having a thickness of 100 mm and a thermal conductivity of 35 W / (m · K) at 1000 ° C. was used.

In Inventive Example 2, a heat insulating material having a material of Al ₂ O ₃ —SiO ₂ —SiC system, a compressive strength of 0.7 MPa and 1.3 MPa at room temperature and 1000 ° C., respectively, and a thickness of 3 mm was used. This heat insulating material was applied between the permanent refractory layer and the iron skin. The heat conductivity of the heat insulating material is 0.15 W / (m · K). The permanent refractory layer had a two-layer joint structure of molded bricks, and the thickness per layer was 30 mm. A work refractory layer having a thickness of 100 mm and a thermal conductivity of 35 W / (m · K) at 1000 ° C. was used.

  In Invention Example 3, a heat insulating material having the same material, the same strength, and the same thickness as in Invention Example 2 was applied between the permanent refractory layer and the iron skin. The permanent refractory layer had a two-layer joint structure of molded bricks, and the thickness per layer was 30 mm. A work refractory layer having a thickness of 100 mm and a thermal conductivity of 35 W / (m · K) at 1000 ° C. was used.

  In Invention Example 4, a heat insulating material having the same material, the same strength, and the same thickness as in Invention Example 2 was applied between the permanent refractory layer and the iron skin. The permanent refractory layer had a two-layer joint structure of molded bricks, and the thickness per layer was 30 mm. A work refractory layer having a thickness of 180 mm and a thermal conductivity of 15 W / (m · K) at 1000 ° C. was used.

  In Invention Example 5, a heat insulating material having the same material and strength as in Invention Example 2 and a thickness of 5 mm was applied between the permanent refractory layer and the iron skin. The permanent refractory layer had a two-layer joint structure of molded bricks, and the thickness per layer was 30 mm. A work refractory layer having a thickness of 180 mm and a thermal conductivity of 15 W / (m · K) at 1000 ° C. was used.

In Invention Example 6, a heat insulating material having a material of Al ₂ O ₃ —SiO ₂ —SiC, a compressive strength of 0.7 MPa and 1.3 MPa at room temperature and 1000 ° C., and a thickness of 5 mm was used. This heat insulating material was applied between the permanent refractory layer and the iron skin. The heat conductivity of the heat insulating material is 0.02 W / (m · K). The permanent refractory layer had a two-layer joint structure of molded bricks, and the thickness per layer was 30 mm. A work refractory layer having a thickness of 180 mm and a thermal conductivity of 15 W / (m · K) at 1000 ° C. was used.

  On the other hand, in the comparative example 1, the permanent refractory layer was 1 layer and the thickness was 60 mm. A work refractory layer having a thickness of 100 mm and a thermal conductivity of 35 W / (m · K) at 1000 ° C. was used. No insulation was constructed.

  In Comparative Example 2, the permanent refractory layer had a two-layer joint structure, and the thickness per layer was 30 mm. A work refractory layer having a thickness of 100 mm and a thermal conductivity of 35 W / (m · K) at 1000 ° C. was used. No insulation was constructed.

In Comparative Example 3, a heat insulating material having a material of Al ₂ O ₃ —SiO ₂ , a compressive strength of 0.2 MPa and 0.35 MPa at room temperature and 1000 ° C., and a thickness of 3 mm was used. This heat insulating material was applied between the permanent refractory layer and the iron skin. The heat conductivity of the heat insulating material is 0.15 W / (m · K). The permanent refractory layer had a two-layer joint structure, and the thickness per layer was 30 mm. A work refractory layer having a thickness of 100 mm and a thermal conductivity of 35 W / (m · K) at 1000 ° C. was used.

In Comparative Example 4, a heat insulating material having a material of Al ₂ O ₃ —SiO ₂ , a compressive strength of 0.2 MPa and 0.35 MPa at room temperature and 1000 ° C., and a thickness of 3 mm was used. This heat insulating material was constructed between two permanent bricks of a permanent refractory layer. The heat conductivity of the heat insulating material is 0.15 W / (m · K). The permanent refractory layer had a two-layer joint structure, and the thickness per layer was 30 mm. A work refractory layer having a thickness of 100 mm and a thermal conductivity of 35 W / (m · K) at 1000 ° C. was used.

In Comparative Example 5, a heat insulating material having a material of Al ₂ O ₃ —SiO ₂ , a compressive strength of 0.2 MPa and 0.35 MPa at room temperature and 1000 ° C., and a thickness of 3 mm was used. This heat insulating material was applied between the workpiece refractory layer and the permanent refractory layer. The heat conductivity of the heat insulating material is 0.15 W / (m · K). The permanent refractory layer had a two-layer joint structure, and the thickness per layer was 30 mm. A work refractory layer having a thickness of 100 mm and a thermal conductivity of 35 W / (m · K) at 1000 ° C. was used.

  About 300 tons of hot metal discharged from the blast furnace was received using the hot metal ladle having the construction conditions of the present invention example and the comparative example, and the amount of decrease in hot metal temperature (° C.) during the hot metal discharge period from the receiving iron was investigated. In addition, since the refractory lining structure is different, the average amount of iron received in each hot metal ladle was investigated. Furthermore, the iron skin temperature of each hot metal ladle was measured using an infrared thermometer, and the maximum iron skin temperature in each condition was compared. In all the investigations, the investigation was performed under the condition that there was no hot metal treatment from receiving to hot metal discharge, that is, the condition that there was no temperature rising process or temperature lowering process in the middle. In addition, the inside of the hot metal ladle was observed at the time of repairing the refractory of these hot metal ladle, the state of the permanent refractory layer was confirmed, the heat insulating material was recovered, and the thickness of the heat insulating material was measured. The survey results are shown in Table 3.

  Invention Examples 1 to 6 that satisfy the conditions of the present invention are low in both the maximum iron skin temperature and the hot metal temperature drop amount compared with any of Comparative Examples 1 to 5, and the effect of heat insulation is effectively obtained. It was. As a result of observing the adhesion state of the metal in the empty hot metal ladle after the hot metal was dispensed, no metal adhesion was observed in the hot metal ladle of Examples 1 to 6 of the present invention, but comparison was not made with a heat insulating material. In Examples 1 and 2, adhesion of the metal was observed. As a result, the average amount of received light also increased in Invention Examples 1 to 6 as compared with Comparative Examples 1 and 2.

  Moreover, when this invention example 1-6 is compared with the comparative example 3, in the invention examples 1-6 with high compressive strength of a heat insulating material, the thickness reduction of the heat insulating material after use was low. Thereby, it became clear by one heat insulation material construction that the heat insulation effect is maintained over the multiple times of reworking work refractory layers without renewing the heat insulation material.

  Here, when the present invention example 2 and the present invention example 3 having different joint structures of the permanent refractory layer are compared, the present invention example 3 which is the joint structure is more in comparison with the present invention example 2 which is the through joint structure. As a result, the deterioration of the permanent refractory layer was low, and there was no intrusion of metal. This is because in Example 3 of the present invention, the stacking structure of the permanent bricks is a joint, so that the load stress in the refractory is relaxed and the effect of suppressing the intrusion of the bare metal to the iron skin side is obtained. is there.

  Furthermore, in Example 4 of the present invention, the thickness of the work refractory layer was increased, and the work refractory layer having a low thermal conductivity was used, so the heat loss was further reduced. In Invention Example 5, the heat insulating material thickness was the maximum value of the optimum conditions, and the amount of hot metal temperature drop could be further suppressed than in Invention Example 4. In Invention Example 6, not only the compressive strength of the heat insulating material but also the thermal conductivity was set to a more advantageous condition, so that the highest heat insulating effect was realized among the examples of the present invention.

  From the above results, it was possible to confirm the superiority of the present invention in which the heat insulation conditions were accurately defined.

DESCRIPTION OF SYMBOLS 1 Hot metal ladle 2 Iron skin 3 Permanent refractory layer 4 Work refractory layer 5 Thermal insulation

Claims (7)

  A refractory lining structure for a steelmaking container for receiving and holding hot metal discharged from a blast furnace, carrying the held hot metal, or performing a refining process on the held hot metal, from the outside of the ironmaking container An iron skin, a permanent refractory layer, and a workpiece refractory layer in this order, and a static iron pressure generated when the compressive strength holds hot metal in the iron making container between the iron skin and the permanent refractory layer. A refractory lining structure for a container for iron making, wherein a heat insulating material having a value equal to or greater than the value is arranged.   2. The iron making according to claim 1, wherein the permanent refractory layer is formed of two or more brick layers of a formed brick having a thickness of 30 mm or more and 65 mm or less at a side wall portion and a bottom portion of the iron making container. Refractory lining structure for containers.   The refractory lining structure for a steelmaking container according to claim 1 or 2, wherein the brick structure of the permanent refractory layer is a joint structure.   The refractory lining structure for a steelmaking container according to any one of claims 1 to 3, wherein the workpiece refractory layer has a thickness of 100 mm or more during construction.   The refractory lining structure for an iron-making container according to any one of claims 1 to 4, wherein the heat insulating material has a thickness of 5 mm or less.   6. The refractory lining of a steelmaking container according to claim 1, wherein the heat insulating material has a thermal conductivity of 0.15 W / (m · K) or less. Construction.   The work refractory layer is made of a molded brick or an irregular refractory having a thermal conductivity of 35 W / (m · K) or less, according to any one of claims 1 to 6. Refractory lining structure for steel making containers.

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