JPH10206031A - Heat insulating lining structure for ladle laying part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To develop a heat insulating lining structure in which there increased the life of a refractory and drying time is shortened with simple construction assuming the use of the unshaped refractory. SOLUTION: In a melted metal ladle bottom part, there is provided an SiO2 -Al2 O3 refractory/heat insulating sheet 3 provided between an alumina/ magnesia unshaped refractory 1 being an inside wear lining in contact with melted metal and an alumina quality unshaped refractory 4 being permanent lining next to an iron skin 5, and further there are provided pyrophyllite brick heat insulating/protective bricks 2 being permanent lining between the refractory heat insulating sheet 3 and the unshaped refractory 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a heat insulating lining of a ladle used in a process of handling molten metal such as iron and steel making, that is, a ladle pad.

[0002]

2. Description of the Related Art Conventionally, fired alumina bricks have been usually used for the innermost wear lining of refractory linings provided in a ladle for molten metal.
Due to the recent decrease in the number of bricklayers and the need for lower ladle costs (longer life), switching to amorphous refractories such as alumina and magnesia is progressing.

[0003] Amorphous refractories are advantageous in terms of construction because they require less labor to load than bricks. However, since water is added, kneaded and poured into the construction, water is sufficiently evaporated before use. Drying is required, and it takes more time to dry than a conventional refractory lining. In addition, when drying is insufficient, there is a danger that rapid evaporation of water will occur during use, destroying the inside of the refractory.

In order to solve such a problem, as a conventional technique, a heat insulating material is arranged on the outer surface of a steel shell during drying to prevent heat dissipation.
There is a proposal to shorten the heating and drying time (Jun 63-3838)
No.). There is also a proposal to provide a decompression hole in the steel shell, connect a vacuum pump from the decompression hole, forcibly deaerate the inside of the refractory lining, and shorten the heating and drying time (Japanese Patent Application Laid-Open No. 6-229685). ).

[0005]

[Problems to be solved by the invention] However, Kimiaki Jitsu
63-3738, the proposal of JP-A-6-229685,
There is a problem that ancillary equipment is required, the apparatus becomes large-scale and the economy is low, and the effect of the present invention can be exhibited only during drying.

Alumina-magnesia amorphous refractories have a greater resistance to erosion and infiltration by slag than bricks and other amorphous refractories, but have a large expansion difference due to temperature, and cracks and peels during use. Is easy to occur. In addition, there is a problem that the thermal conductivity is higher than that of the conventional brick, and the heat loss during operation is large.

[0007] Thus, an object of the present invention is to provide a heat insulating lining that can shorten the drying time and extend the life of a refractory, despite the simple construction, on the premise that an amorphous refractory is used. Is to develop the structure.

[0008]

SUMMARY OF THE INVENTION Therefore, in order to solve these conventional problems, the present invention aims to solve the above-mentioned conventional problems in a ladle lay for molten metal, in which a refractory which is a wear lining and an irregular which is a permanent lining. With the idea of providing a fire-resistant heat insulating sheet between the refractory and the purpose of further protection of this fire-resistant heat insulating sheet, and by providing a protective brick for the remaining thickness guide of the wear lining, shortening the drying time, Knowing that the life of a refractory can be extended, the present invention was completed.

Therefore, the present invention provides a molten metal ladle bed formed by a refractory lining, comprising an irregular refractory, which is an inner wear lining in contact with the molten metal, and a permanent lining adjacent to a steel shell. A molten metal container comprising a refractory heat insulating sheet provided between a certain refractory material and a heat insulating protective brick which is a permanent lining between the refractory heat insulating sheet and the refractory material. It is a heat insulating lining structure of the potbed part.

[0010]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic sectional view showing a ladle lay for molten metal according to the present invention. According to the present invention, as shown in FIG. In the potbed portion 10, a fire-insulating sheet 3 is provided between the irregular-shaped refractory 1 as a wear lining and the irregular-shaped refractory 4 as a permanent lining. Protective bricks 2 are provided to indicate the remaining thickness.

The entire outside of the ladle 10 is surrounded by a steel shell 5, and the side walls are also provided with a wear lining and a refractory lining which is a permanent lining. However, the present invention is not particularly limited thereto.

In the present invention, the refractory heat insulating sheet 3 is provided in order to enhance the heat insulating effect on the wear lining, whereby the heat insulating effect of the refractory of the ladle lay portion is enhanced, as will be described later. Even if alumina / magnesia is used as the wear lining, heat loss is reduced, which is preferable in terms of operation.

According to the present invention, the amorphous refractory 1 which is a wear lining is preferably made of alumina / magnesia, which is currently the most excellent corrosion resistance and infiltration resistance among the irregular refractories.

The protective brick 2 has a low thermal conductivity, exhibits thermal insulation, and is likely to come into contact with molten steel. Therefore, it is suitable to use a high-fired brazing stone or a medium to high alumina brick. It is desirable to use low-cost, inexpensive pyroxene bricks.

The refractory heat-insulating sheet 3 preferably has a low thermal conductivity and excellent heat insulation properties, and is as thin as possible, for example, 1 to 10 mm in consideration of contact with molten steel. Preferably, it is composed of a fibrous amorphous (Al ₂ O ₃ —SiO ₂ ) body. The size should just occupy a substantial area of the ladle bed. In addition, specifically, at the time of installation, the thickness is 1 to 2
It may be performed by providing a refractory heat insulating sheet of a predetermined thickness on the refractory mortar layer of mm and further providing a refractory mortar layer of 1 to 2 mm thickness thereon and fixing the whole. As the amorphous refractory 4 which is a permanent lining, it is desirable to use an alumina-based amorphous refractory having a low thermal conductivity and a high fire resistance.

Thus, by performing the lining having the above-described configuration according to the present invention, the provision of the refractory heat-insulating sheet 3 makes it possible to reduce the amount of heat dissipated when the amorphous refractories 1 and 4 are dried. The time for completely evaporating the water, that is, the drying time can be reduced.

By the effect of the fire-resistant heat insulating sheet 3, the temperature difference in the wear lining at the time of receiving steel (heat reception) can be reduced, and the cracks of the irregular-shaped refractory 1 constituting the wear lining can be suppressed.

Due to the effect of the refractory heat insulating sheet 3, the amount of heat dissipated during the transportation of hot metal and molten steel is reduced, and the temperature drop can be reduced. By making the perm lining an irregular shaped refractory,
Joints are eliminated, and steel leakage due to molten steel entering the joints can be avoided.

The heat insulation sheet can be safely lined on the ladle bed part which is relatively damaged as compared with other parts in the container. This is because the protective brick 2 is provided. Using the joint of the heat-insulating protective brick 2 as a guide, the remaining thickness of the wear lining can be easily grasped. And other excellent effects.

[0020]

EXAMPLE In this example, the bed of a 250-ton molten steel ladle was used as a heat insulating lining structure shown in FIG. 1 and the following materials were used.

Unshaped refractories (wear lining) 1:
Alumina-magnesia amorphous material with a thickness of 200 mm (Al ₂ O ₃ 92
%, MgO 5%, CaO 1.4%). Insulating protective brick (permanent lining) 2: 30 mm thick low stone brick (70% SiO ₂ , 25% Al ₂ O ₃ ). Fireproof insulation sheet 3: Fireproof insulation sheet (SiO ₂ 5
2%, Al ₂ O ₃ 48%, amorphous). Irregular refractories (permanent lining) 4: thickness 120
mm alumina shaped refractory (Al ₂ O ₃ 50%, SiO ₂ 41
%).

After the application with such a material, a temperature measuring point was provided at the point shown in FIG. 2 and drying was performed by a drying burner. The installation area of the fire-resistant insulation sheet 3 and the protective brick 2 occupies almost the entire ladle floor. FIG. 3 shows the temperature transition during drying in comparison with that of the conventional example.

The temperature of the back of the wear lining rises faster due to the effect of the heat insulating sheet, and the time (drying time) required to reach 350 ° C. (drying end temperature), which is a temperature at which water is completely evaporated and there is no fear of explosion, is obtained. About 8 hours can be reduced.

Table 1 shows the temperature gradient and the amount of heat dissipated in the heat insulating lining structure according to the present invention when molten steel is actually charged. According to the present invention, the temperature difference (/ boundary temperature) in the wear lining can be reduced by about 60 ° C., cracking and peeling of the floor can be reduced, and the irregular shape of the floor used in one campaign can be reduced. The amount of refractory repair materials was reduced by about 15% compared to the conventional model.

Further, the amount of heat dissipated can be reduced, which is effective in reducing the temperature drop of the molten steel. These excellent effects are achieved by the heat-insulating protective bricks 2 and the fire-resistant insulation sheets 3.
By preventing the exposure of the ladle, the ladle could be used until the end of its use, effectively extending its life.

[0026]

[Table 1]

[0027]

As described above, by forming the molten metal ladle bedding with the heat insulating lining structure according to the present invention, the heat insulating lining can be safely disposed on the relatively damaged floor. The effect of shortening the drying time of the fixed refractory, reducing the damage of the wear lining, and suppressing the temperature drop of the hot metal and molten steel can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a heat insulating lining structure according to the present invention.

FIG. 2 is an explanatory diagram showing temperature measurement points of a ladle pad portion.

FIG. 3 is a graph showing a temperature transition during drying.

[Explanation of symbols]

 1: Irregular refractories (wear lining) 2: Protective bricks for thermal insulation 3: Refractory thermal insulation sheet 4: Irregular refractories (permanent lining)

Claims (1)

[Claims] 1. In a ladle for molten metal constituted by a refractory lining, an irregular refractory 1 which is an inner wear lining in contact with the molten metal and an irregular form which is a permanent lining adjacent to a steel shell 5. The refractory insulation sheet 3 is provided between the refractory 4 and the refractory insulation sheet 3.
A heat insulating lining structure for a ladle for molten metal, comprising a heat insulating protective brick 2 which is a permanent lining between the refractory 1 and the refractory 1.