TW201600491A - Process for producing lining structure of vessel for molten metal, and lining structure of vessel for molten metal - Google Patents

Abstract

Provided are the lining structure of a vessel for molten metals and a method for lining a vessel for molten metals, which are rendered possible at a lower cost than ever before while maintaining the refractory performance. The lining structure of a vessel for molten metals according to the present invention includes: a heat insulator interposed between an outer steel shell and a permanent lining refractory and having a coefficient of heat transfer of 100 W/m2K or less; and an inner lining refractory that is a refractory obtained by applying an unfired refractory or unshaped refractory which contains 60 mass% or more alumina and 4 mass% or more magnesia, 50 mass% or more of the magnesia being periclase or calcined dolomite, and which, after a 3-hour heat treatment at 1,500 DEG C, has a residual expansion of 0.8% or greater, to the vessel for molten metals and then converting the alumina and magnesia to spinel.

Description

Method for producing lining structure of molten metal container, and lining structure of molten metal container

The present invention relates to a method for producing a lining structure of a molten metal container and a lining structure for a molten metal container.

a lining structure system of various molten metal containers such as a torpedo car, a blast furnace, a steelmaking converter, a molten steel ladle, etc., to provide an outer steel on the outermost side of the molten metal container (outer steel) Shell), which is composed of a permanent lining refractory and a lining refractory toward the inside of the molten metal container. The working face (of refractory) of the innermost lining refractory is in contact with the molten metal. The properties of the refractory lining the molten metal container are required to have corrosion resistance to the molten metal, the slag of the coexisting molten oxide, and the like, and the spalling caused by the temperature change. patience.

Generally, a lining refractory containing alumina (magmina) is sintered by post-construction. Spinelization travels. As the volume of the spinel is expanded, the volume of the refractory expands and the voids present in the refractory are reduced. Thereby, the refractory can be made compact, the porosity can be lowered, and the slag can be prevented from intruding into the refractory, so that the refractory wear rate can be reduced.

In the use of the molten metal container, an imminent temperature rise and fall occurs in the vicinity of the running surface of the lining refractory. Therefore, as described above, the following problem arises when the method of making alumina and bitter soil spinel after the lining of the lining is applied to the molten metal container. That is, when the spinel in the vicinity of the running surface of the lining refractory is not sufficiently performed, the temperature due to the heating of the molten metal from the use process rises due to the thermal expansion of the lining refractory due to the thermal expansion and the accompanying tip. The expansion of the structure of the crystal petrochemical causes a problem of cracking of the lining refractory.

On the other hand, Patent Document 1 discloses that a refractory for lining is used, and alumina and bitter soil which are not sputtered and petrified are used as main materials, and after refractory construction for the inner lining, the temperature is 1300 ° C or higher. The firing is carried out for 4 hours or more, whereby the lining is sputtered with a refractory before the molten metal container is used.

Patent Document 2 proposes to add a small amount of silica which lowers the melting point, and the spinel petrochemical is rapidly carried out.

[Advanced technical literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. Hei 10-167846

[Patent Document 2] Japanese Patent No. 4220131

However, in the method disclosed in Patent Document 1, it is proposed to use a burner to heat the running surface of the lining refractory at 1300 ° C or higher and to heat it for 4 hours or more before use of the molten metal container, thereby lining the refractory. Petrochemicals travel, but in order to heat the running surface of the lining refractory at 1300 ° C or above, strong blowtorch equipment must be used. Further, since the temperature inside the refractory is lowered from the running surface toward the direction in which the refractory is permanently lining, that is, in the direction of the back surface of the refractory, the inside of the lining refractory is sufficiently heated for heating for 4 hours or longer. Spinel petrochemicals must require huge amounts of energy. Therefore, the application of the method disclosed in Patent Document 1 is not economical.

In Patent Document 2, a small amount of cerium oxide having a lowered melting point is added to partially generate a liquid phase, whereby a general solid phase is diffused and rapidly crystallized. However, the reduction in the fire resistance caused by the addition of cerium oxide may impair the advantages of the spinel and petrochemical which make the refractory compact and prevent the intrusion of the slag, and it takes a sufficient time to carry out the addition of cerium oxide. In the case of preheating, there is a problem of poor fire resistance.

The present invention has been developed in order to solve such a problem, and an object of the invention is to provide a method for producing a lining structure of a molten metal container which has sufficient fire resistance without requiring a conventional torch device, and a molten metal. The lining structure of the container.

The present invention has been developed in order to solve such a problem, and has the following features.

[1] A method for producing a lining structure of a molten metal container, which is a method for producing a lining structure having a permanent lining refractory and a lining refractory-lined molten metal container from the outer side of the iron sheet, characterized in that: A heat insulating material having a heat transfer coefficient of 100 W/m ² K or less is provided between the iron sheet and the permanent lining refractory, and the coating contains 60% by mass or more of alumina and 4% by mass or more of bitter soil and is carried out at 1500 ° C. In the case of an unfired refractory and/or an unshaped refractory as the aforementioned lining refractory, the linear change rate at room temperature before and after the heat treatment is 0.8% or more, and the molten metal container is used. Before, the running surface of the aforementioned lining refractory is preheated.

[2] The method for producing a lining structure of a molten metal container according to the above [1], wherein the lining refractory before the construction is 50% by mass or more of the bitter soil, comprising pericyl or baking. Calcined dolomite, preheating before the use of the aforementioned molten metal container, is the aforementioned lining refractory before construction, preheating to a portion of alumina and spinel of periclase or burnt dolomite bitter soil Petrochemical.

[3] A lining structure of a molten metal container, characterized in that: It is produced by the method for producing a lining structure of a molten metal container as described in [1] or [2].

According to the present invention, it is possible to provide a method for producing a lining structure of a molten metal container and a lining structure for a molten metal container which have sufficient fire resistance without requiring a conventional torch device.

1‧‧‧ 铁皮

2‧‧‧Insulation

3‧‧‧Permanent lining refractory

4‧‧‧ lining refractory

Fig. 1 is a view showing a lining structure of a molten metal container according to an embodiment of the present invention.

Fig. 2 is a graph showing the relationship between the distance from the running surface of the lining refractory of Example 1 (with heat insulating material) and Comparative Example 3 (without heat insulating material) and the spinel ratio of bitter soil.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

First, an outline of the present invention will be described. The invention relates to the manufacture of a lining structure of a molten metal container, and finds that after the lining refractory is constructed, a material capable of allowing alumina and bitter soil spinel to be used as a lining refractory is used, and the heat insulating layer is interposed. Between the iron sheet and the permanent lining refractory, the equipment cost and energy cost will not be deteriorated, and The development was completed by reducing the cost of refractories.

That is, more than half of the bitter soil is blended as periclase or calcined dolomite, in order to reduce the refractory by the spinel petrochemical and reduce the internal The crack caused by the rapid expansion of the temperature at which the lining refractory starts to rise and the synthetic expansion accompanying the expansion of the spinel petrochemical is provided with a heat insulating layer closer to the iron side than the lining refractory. Thereby, the temperature gradient inside the lining refractory can be made gentle, and the temperature of the back surface of the lining refractory and the portion to the back surface can be increased. As a result, when the preheating after construction is increased, the ratio of the spinel and petrochemical is increased, and the spinel petrochemical is further advanced to a sufficiently deep portion, and the spinel petrochemical after the actual start of use, that is, after the lining refractory starts to operate, is relatively reduced. The expansion of the travel can suppress cracking. Thereby, the equipment cost and the energy cost are not deteriorated, and the refractory cost can be greatly reduced. Further, the back surface of the lining refractory means the surface opposite to the running surface, that is, the surface in contact with the molten metal.

Fig. 1 is a view showing an example of a lining structure of a molten metal container according to an embodiment of the present invention. A metal sheet 1 is provided on the outermost side of the molten metal container. The lining structure is in contact with molten metal (not shown) on the inside, that is, on the right side of the paper. The lining structure system is provided with a heat insulating material 2, a permanent lining refractory 3, and a lining refractory 4 in this order from the iron sheet 1 toward the inner side, that is, in the direction in which the molten metal enters (the lining direction).

The heat insulating material 2 is provided in the lining structure between the permanent lining refractory 3 and the iron sheet 1, and the heat insulating material 2 has a heat transfer coefficient of 100 W/m ² K or less. Generally, the permanent lining refractory 3 has a heat transfer coefficient of about 100 W/m ² K. Here, the heat transfer coefficient refers to each refractory layer such as the lining refractory 4, the permanent lining refractory 3, and the heat insulating material 2, and the thickness of each layer is divided by the values of the respective thermal conductivities.

By forming the heat insulating material 2 as a heat insulating material having a heat transfer coefficient of 100 W/m ² K or less which is lower than the permanent lining refractory 3, the temperature gradient inside the lining refractory 4 can be made gentle and can be By increasing the temperature of the back surface and the back surface, it is possible to sufficiently perform the spinelization of the lining refractory 4 by the preheating before use. The heat insulating material 2 is generally porous and has low fire resistance. Therefore, in order to keep the temperature of the heat insulating material 2 low, it is provided between the iron sheet 1 and the permanent lining refractory 3.

Here, the thermal conductivity of the inexpensive heat insulating material is about 0.3 W/mK. When such a heat insulating material is applied as the heat insulating material 2, and the construction thickness is 3 mm, the heat transfer coefficient becomes 100 W/m ² K. For example, a nanoporous heat insulating material having a construction thickness of 6 mm and a heat transfer coefficient of 50 W/m ² K or a slightly high heat conductivity of about 0.03 W/mK can be used. When the transmission coefficient is lowered to 10 W/m ² K, the effect of the present invention can be further increased.

The permanent lining refractory 3 is generally composed of a brick such as alumina or the like, and the joint is buried with mortar. The heat transfer coefficient of the permanent lining refractory 3 is about 100 W/m ² K. In Fig. 1, one layer is illustrated, but the permanent lining refractory 3 may also be provided in two layers.

The lining refractory 4 is an unsintered refractory and/or an amorphous refractory containing alumina and bitter soil, which are sintered by refractory construction to make alumina and bitter spinel. Furthermore, "non-sintering fire resistance "Material" means a refractory that has not been previously fired before construction, and "unshaped refractory" means a refractory that has not been previously formed before construction. It is preferable that the lining refractory 4 is composed of one or both of a non-sintered refractory containing 60% by mass or more of alumina, 4% by mass or more of bitter soil, and an amorphous refractory. More preferably, the lining refractory 4 is required to contain 80% by mass or more of alumina and 5% by mass or more of bitter soil in addition to the case where graphite or the like is blended for a specific use.

Further, 4,50% by mass or more of the lining refractory before the spinel and the bitter soil are subjected to spinel and petrochemical is contained in the refractory as periclase or calcined dolomite. Thereby, since the ratio of the spinel and petrochemical can be increased after the application, the effect of tightening the lining refractory 4 or improving the corrosion resistance can be obtained. Here, it is preferable that 90% by mass or more of the bitter soil is supplied as the periclase, depending on the market situation of the raw material price.

The non-sintered refractory and/or the monolithic refractory constituting the lining refractory 4 are adjusted to have a linear change rate of room temperature before and after heat treatment at 1500 ° C for 3 hours (hereinafter also referred to as linearity after heat treatment at 1500 ° C). The rate of change is made 0.8% or more. By setting the linear change rate after the heat treatment at 1500 ° C to 0.8% or more, the lining structure including the heat insulating material 2 is used, and during the preheating after the refractory construction and after being used as the molten metal container ( After the operation, the effect of improving the corrosion resistance of the lining refractory 4 is obtained by the spinel of the alumina and the bitter soil. Here, the reason why the heat treatment temperature is 1500 ° C and the heat treatment time is 3 hours is considered as the temperature history of the molten metal container, and the temperature history of the running surface side of the lining refractory 4 after use (after running) tip The reason for the compaction of the refractory 4 lining the crystal petrochemical.

In addition, when the linear change rate of the room temperature after the heat treatment at 1500 ° C is less than 0.8%, even when the lining structure including the heat insulating material 2 is used, the lining refractory 4 cannot be sufficiently obtained. And improve the effect of corrosion resistance. In addition, when the linear change rate of the room temperature after the heat treatment at 1500 ° C is 0.8% or more in the lining structure of the layer containing the heat insulating material 2, the spin crystal is spun at a low temperature during preheating after the construction. Since the ratio of the petrochemical is low, the expansion of the lining refractory 4 at the initial stage of operation (operation) causes the expansion due to the spinel petrification to proceed violently. Therefore, the thermal expansion of the lining refractory 4 after the initial temperature rise is started. The expansion of the expansion with the spinel petrification causes cracking, and the effect of increasing the corrosion resistance and prolonging the service life of the refractory by the tightening of the refractory by the spinel is not sufficiently obtained.

Further, in order to improve the corrosion resistance by tightening the lining refractory 4, it is more desirable to set the linear change rate at room temperature after heat treatment at 1500 ° C to 1.5% or more. Here, the linear change rate after the heat treatment at 1500 ° C corresponds to a positive value of expansion and a negative value, respectively, and is made of bitter soil which is contained in the refractory of the refractory material as periclite or fired dolomite. The method of increasing the content can be increased, and it can be adjusted so as to reduce the amount of titanium oxide, iron oxide, and cerium oxide contained in the refractory, such as impurities.

In addition, the refractory of the lining refractory 4 supplied to the molten metal container can be sufficiently made to be lysed by spinel by using a material containing 60% by mass of alumina and 4% by mass or more of bitter soil. Resistance The effect of erosion improvement.

In the lining structure described above, in the case where the heat insulating material 2 is interposed between the iron sheet 1 and the permanent lining refractory 3, the effect of the spinel lining of the lining refractory 4 is promoted, and it can be used in a molten metal container. The drying and preheating process of the front lining refractory 4 is produced.

In the past, when the lining refractory 4 was dried and preheated, if the temperature of the running surface of the lining refractory 4 was maintained at 1300 ° C or more and 4 hours or more, the spinel lining of the lining refractory 4 did not travel. . On the other hand, in the present invention, the temperature of the running surface of the lining refractory 4 is raised to the back side of the lining refractory 4 by providing the heat insulating material 2 having a heat transfer coefficient of 100 W/m ² K or less. At 800 ° C, the spinel lining of the lining refractory 4 near the running surface can be sufficiently advanced. Further, from the viewpoint of shortening the drying and preheating time, it is more desirable that the temperature of the surface (running surface) of the lining lining at the end of the drying and preheating process is 900 to 1200 °C.

Therefore, it is possible to effectively suppress the crack caused by the rapid temperature rise caused by the heat of the molten metal from the start of use of the molten metal container. In addition, the cost of the refractory can be greatly reduced without deteriorating the equipment cost and the energy cost. Further, since it is not necessary to add cerium oxide as in the prior art, the fire resistance can be maintained.

[Examples]

Next, an embodiment relating to the present invention will be described. The effect of the present invention was investigated using the lining structure shown in Fig. 1 . In addition, the conventional example which investigated, the comparative examples 1 to 5, and the invention example 1 are shown in Table 1. In this In Inventive Example 1, all components including bitter soil other than periclase are non-sintered refractories and/or monolithic refractories.

(Conventional Example) In the lining structure, 91% by mass of alumina-6 mass% bitter soil is used as the lining refractory 4, and 5/6 of the bitter soil (mass basis) is previously used as alumina-bitter soil An inflow-type monolithic refractory of a material having a linear change rate of room temperature of 1500 ° C after the heat treatment at 1500 ° C. In the conventional example, the heat insulating sheet 2 was not constructed. The permanent lining refractory 3 has a heat transfer coefficient of 100 W/m ² K. The service life is 225 heats.

(Comparative Example 1) In the lining structure shown in Fig. 1, as the lining refractory 4, 91% by mass of alumina-6 mass% bitter soil similar to the conventional example was used, and 5/6 of the bitter soil was used ( The mass standard) is an inflow type amorphous refractory of a material having a linear change rate of room temperature of 0.1% after heat treatment at 1500 ° C, which is prepared in advance as alumina-bitrite spinel. An insulating sheet 2 having a thermal conductivity of 0.2 W/mK and a thickness of 3 mm was applied between the iron sheet 1 and the permanent lining refractory 3 . The total heat transfer coefficient of the heat insulating sheet 2 and the permanent lining refractory 3 is 40 W/m ² K. As a result, the service life is deteriorated by 20% compared to the conventional example.

When the refractory after use is recovered and investigated, the depth of penetration of the slag component such as calcium oxide or cerium oxide into the refractory is 40 mm deep for a normal 30 mm, and cracks are also formed at the boundary portion. . In general, when heat is applied to the back side of the refractory, the temperature of the refractory material rises and the durability is deteriorated, and the material of the alumina-bitter soil system has the same result.

(Comparative Example 2) Next, as the lining refractory 4, 91% by mass of alumina-6 mass% bitter soil was used, and 4/4 of the bitter soil was used. The amount of the standard is an inflow type amorphous refractory of a material having a linear change rate of 0.3% after heat treatment at 1500 ° C which is prepared in advance as alumina-bitrite spinel. The same heat insulation as in Comparative Example 1 was carried out. As a result, the infiltration depth was reduced to about 30 mm, but the life of the lining refractory 4 was the same as or worse than the conventional example.

(Comparative Example 3), as the lining refractory 4, 91% by mass of alumina - 6% by mass of bitter soil, and 95% by mass or more of bitter soil, which is formulated as a magnesite, is linear after heat treatment at 1500 ° C. An inflow type amorphous refractory of a material having a rate of change of 1.5%. Further, in Comparative Example 3, there was no actual heat insulating sheet. As a result, the life of the lining refractory 4 is about 11% longer than that of the conventional example.

(Comparative Example 4) As the lining refractory 4, an inflow type monolithic refractory made of 94% by mass of alumina-3 mass% bitter soil and 95% by mass or more of bitter clay as a material for blending with periclase is used. The same heat insulating sheet as in Comparative Example 1 was constructed. As a result, the life of the lining refractory 4 was longer than that of the conventional example, but it was shorter than that of the comparative example 3. This is because even if a bitter soil having a high ratio of periclase is used, when the total amount of bitter soil is less than 4% by mass, the linear change rate of room temperature after heat treatment at 1500 ° C is 0.7% lower, and refractory cannot be obtained. The effect of compaction.

(Comparative Example 5) As the lining refractory 4, an alumina raw material having a slightly larger amount of impurities and 90% by mass of alumina-6 mass% bitter soil and 95% by mass or more of bitter soil were used as the periclite. Inflow of a material having a linear change rate of 0.7% after heat treatment at 1500 ° C in which the impurities (titanium oxide, iron oxide, and cerium oxide) of the alumina raw material are 1% by mass The amorphous refractory was molded, and the same heat insulating sheet as in Comparative Example 1 was applied. As a result, the life of the lining refractory 4 was longer than that of the conventional example, but it was shorter than that of the comparative example 3. This is because even if a bitter soil having a high ratio of periclase is used, the linear change rate at room temperature after heat treatment at 1500 ° C is 0.7% lower due to the influence of impurities which are likely to cause a low melting point liquid phase, and fire resistance cannot be obtained. The effect of the compaction of the object.

Further, in the other comparative examples, the conventional examples, and the lining refractory 4 used in the first embodiment of the present invention, the impurities (titanium oxide, iron oxide, and cerium oxide) derived from the alumina raw material were 0.5% by mass. In any of the experimental examples shown in Fig. 1, the residual portion other than the sum of the numerical values shown by the composition is a component derived from the alumina of the bitter soil raw material and the alumina cement, and impurities other than the bitter soil.

(Inventive Example 1) As the lining refractory 4, 91% by mass of alumina-6 mass% bitter soil similar to that of Comparative Example 3 was used, and 95% by mass or more of bitter soil was blended as ferrargsite at 1500 °C. The material has a linear rate of change of room temperature of 1.5% after heat treatment. Further, the same heat insulating sheet as in Comparative Example 1 was applied. As a result, the life of the lining refractory 4 is about 33% longer than that of the conventional example.

That is, this is because the life of Comparative Example 3 is extended by 11% due to the change in the life of the material of the lining refractory 4, and the life of the layer of the heat insulating material 2 is extended, and the present invention is invented. The difference from the life extension of Comparative Example 3 was 22%.

In the lining structures of Inventive Example 1 and Comparative Example 3, the temperature of the running surface of the lining refractory 4 was set at the end of preheating before use. The spinel ratio of the lining refractory 4 after preheating for 48 hours at 1200 ° C is shown in Fig. 2 . Fig. 2 is a graph showing the relationship between the distance from the running surface of the lining refractory of Example 1 (with heat insulating material) and Comparative Example 3 (without heat insulating material) and the spinel ratio of bitter soil. The thickness of the lining refractory 4 is 130 mm.

In Comparative Example 3 which does not have the heat insulating material 2, in the inventive example 1 having the heat insulating material 2, the spinel ratio in each portion is 24 to 30 points higher, particularly in the depth portion of 56 to 75 mm in the center portion. It is as high as 35% with respect to 11%, and the ratio of spinel to petrochemical ratio is 3.2 times for Comparative Example 3.

In this way, it is found that 60% by mass or more of the alumina and 4% by mass or more of the bitter soil and 50% by mass or more of the bitter soil are the lining refractory 4 supplied as the periclase by the iron sheet 1 A heat insulating material having a heat transfer coefficient of 100 W/m ² K or less is provided between the permanent lining refractory 3 and the durability of the lining refractory 4 can be prolonged.

Furthermore, the present invention is not limited to the above embodiment, and of course, various design changes can be applied.

1‧‧‧ 铁皮

2‧‧‧Insulation

3‧‧‧Permanent lining refractory

4‧‧‧ lining refractory

Claims (3)

A method for producing a lining structure of a molten metal container is a method for producing a lining structure of a molten metal container having a permanent lining refractory and a lining refractory in this order from the iron sheet side, characterized in that the iron sheet and the permanent lining are A heat insulating material having a heat transfer coefficient of 100 W/m ² K or less is provided between the refractories, and the back chamber is heated before the heat treatment at 1500 ° C for 3 hours by applying 60% by mass or more of alumina and 4% by mass or more of bitter soil. The non-sintered refractory and/or the monolithic refractory which is the lining refractory of the above-mentioned lining refractory is preheated before the molten metal container is used, and the running surface of the lining refractory is preheated before the molten metal container is used. The method for producing a lining structure for a molten metal container according to the first aspect of the invention, wherein the lining refractory before the construction, the barium or the dolomite is contained in 50% by mass or more of the bitter soil, The preheating before the use of the molten metal container is the lining refractory before the construction, and preheating a part of the alumina and the spinel petrification of the bituminous or calcined dolomite. A lining structure characterized by being produced by a method for producing a lining structure of a molten metal container according to claim 1 or 2.