JP2510352B2 - Blast furnace tap iron cover covering method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method of lining a blast furnace tappipe cover.

[Prior Art] In blast furnace tapping, the gutter cover has the role of keeping the hot metal warm and preventing the spread of hot metal and slag. In recent years, the operation of a blast furnace tends to be high in temperature and pressure, and due to the severer operating conditions, the durability of the gutter cover is greatly reduced.

Therefore, for example, as disclosed in Japanese Patent Laid-Open No. 2-77510, a refractory for a gutter cover containing silicon carbide and carbon has been proposed. By blending a large amount of silicon carbide, this material is effective for corrosion resistance, spalling resistance and weight reduction.

[Problems to be Solved by the Invention] However, the above-mentioned conventional gutter cover material has high thermal conductivity due to the presence of a large amount of silicon carbide, and does not sufficiently exhibit the properties of the lining material due to the red heat of the iron shell. I had to stop using the gutter cover.

[Means for Solving the Problems] Red heat of the iron skin can be prevented by interposing a heat insulating layer on the back surface of the lining. However, when the heat insulating layer is interposed, the construction time of the gutter cover is greatly extended, and thus there is a problem that the construction is inferior. For example, if the heat insulating layer is to be cast, the lining material must be applied after the heat insulating layer has hardened, and the waiting time is considerably long. In addition, the steel skin is provided with a number of studs to hold the lining material, and if heat insulating bricks or boards are used as the heat insulating layer, the studs must be avoided and installed quickly. Construction was difficult.

The present invention solves the above problems in the construction of a gutter cover. The feature is that after forming a heat insulating layer with a thermal conductivity of 3.0 kcal / m ・ h ・ ° C or less by spraying on the inside of the iron skin provided with many studs for pulling and supporting the lining layer, further This is a method of lining a blast furnace tap pipe cover in which an lining layer made of silicon carbide accounts for 40% by weight or more of the aggregate is formed inside.

Since the formation of the heat insulation layer by spraying cures quickly, the subsequent lining layer can be immediately cast. Unlike insulation bricks or insulation boards, spraying makes it easy to apply insulation layers without taking measures to avoid studs.

Since a large amount of construction water is added, the spraying has a porous structure and has an excellent heat insulating effect. In addition, it is lightweight due to the porous structure, which reduces the overall weight of the gutter cover. This reduction in weight is effective in improving the efficiency of the gutter cover transportation work.

 The present invention will be described in more detail with reference to the drawings.

FIG. 1 is a sectional view of the gutter cover at a right angle to the length direction. The construction is reversed so that the iron skin is on the bottom.

In FIG. 1, 1 is an iron skin, 2 is a large number of studs provided inside the iron skin, 3 is a heat insulating layer, and 4 is an lining layer.

The studs 2 serve to pull and support the lining layer and reach the lining layer 4. The shape is not limited to that shown in FIG. The material of the stud is preferably metal in terms of strength and economy, but may be made of ceramic.

First, the heat insulating layer 3 is formed on the inner surface of the iron shell 1 by spraying. The specific material of the heat insulating layer 3 is not particularly limited, and is, for example, one selected from alumina, high alumina, silica, alumina-silica, magnesia, spinel, silicon carbide or brick scraps containing these as main materials. Alternatively, two or more kinds are used. To this, one or more selected from, for example, sodium phosphate, sodium silicate, hydraulic cement and the like is added as a binder. The proportion of the binder is, for example, 3 to 10% by weight of sodium phosphate, sodium silicate, etc., and 5 to 10% of hydraulic cement.
30 wt%. In addition, if necessary, one or more kinds selected from fibers, deflocculants, slaked lime, metal powder, foaming agents, lightweight aggregates, carbon, nitride, glass, etc. may be added in an appropriate amount.

For spraying the heat insulation layer 3, apply construction water to the outside to keep it at 10-15wt%.
Add about. As the spraying method, a warm method in which construction water is added and mixed from the beginning and a dry method in which construction water is added in a nozzle are known, but the latter dry method is preferable from the viewpoint of workability.

The heat insulating layer 3 needs to be formed by spraying as described above, and at the same time, have a thermal conductivity of 3.0 kcal / m · h · ° C or less. Since the material of the lining layer 4 used in the present invention has high thermal conductivity, the thermal conductivity of the heat insulating layer 3 is 3.0 kcal / m · h.
・ If the temperature exceeds ℃, it is impossible to prevent the red heat of the iron skin.

Unlike the casting, the spraying has a short time until the construction site is filled after adjusting to the sludge state, so that the curing time can be set short. Therefore, it cures quickly,
After the construction, the lining layer 4 can be immediately cast inside.

The thickness of the heat insulating layer 3 is appropriately determined according to the heat insulating properties of the heat insulating layer 3, the thermal conductivity and the corrosion resistance of the lining layer 4, and the like. For example, 1/2 to 1/4 of the total thickness of the gutter cover excluding the iron skin 1 is preferable.

The lining layer 4 formed by casting is 40 wt% of the aggregate.
Above, preferably 40 to 90 wt% is composed of silicon carbide. Fe of the pig iron component produces FeO by oxidation, and the SiC component of silicon carbide reduces this FeO to Fe having a weak erosion power, thereby improving the corrosion resistance of the lining layer 4. This is shown as a reaction formula below.

Silicon carbide prevents the intrusion of pig iron and slag and has an effect of structurally preventing spalling. Further, since silicon carbide has many voids in the particles, its composition is effective in reducing the weight of the gutter cover.

Aggregates other than silicon carbide are, for example, alumina, high alumina,
1 selected from silica, alumina-silica, magnesia, spinel, or brick scrap made from these
Seed or two or more. To the inner lining layer 4, for example, alumina cement as a binder is externally added to the inner layer 4 in an amount of about 1 to 10 wt%. As the binder, not only alumina cement but also alumina cement and aluminum phosphate may be used in combination. Also known as additives for refractory for casting molding, for example, fibers, alumina sol, silica sol, refractory ultrafine powder, peptizer, metal powder,
You may add 1 type (s) or 2 or more types selected from a foaming agent, a lightweight aggregate, carbon, a nitride, etc. in an appropriate amount. The construction water is applied outside, for example, 5 to 10 wt%.

[Examples] Examples of the present invention and comparative examples are shown below.

Table 1 shows the refractory composition used for the heat insulation layer. Table 2 shows the refractory composition used for the lining layer. And Table 3 shows the construction method and the test result of each Example and Comparative Example.

Examples 1 to 5 After forming a heat insulating layer inside the pig skin by a spraying method, a lining layer was formed thereon by casting.

Comparative Examples 1 and 2 Only the lining layer was formed without interposing the heat insulating layer.

Comparative Examples 3 and 4 Both the heat insulating layer and the lining layer were formed by casting.

As is clear from the results shown in Table 3, the gutter covers obtained according to the examples of the present invention do not have the red heat of the iron skin, are lightweight, and have excellent durability. Also, the time required for construction is short.

On the other hand, in Comparative Example 2, since the heat insulating layer was not interposed, the red heat of the iron skin was observed early in the actual machine test and the durability was poor. In Comparative Example 3, the heat insulating layer was cast and formed, so the hardening of the heat insulating layer was slow and the time required for construction was long. In Comparative Example 4, the heat conductivity of the heat insulating layer is high, and the effect of preventing red heat cannot be obtained. Comparative Example 1 has a low content of silicon carbide in the lining layer and is poor in durability.

[Effect] As described above, according to the present invention, a gutter cover having excellent workability and durability can be obtained by combining the heat insulating layer formed by spraying and the silicon carbide lining layer. Therefore, the construction method of the present invention is extremely valuable in the gutter cover, which is expected to be used under severer conditions.

[Brief description of drawings]

FIG. 1 is for explaining the construction method of the embodiment of the present invention, and shows a cross-sectional view perpendicular to the longitudinal direction of the gutter cover constructed by the construction method of the embodiment of the present invention. 1 ... iron skin, 2 ... studs 3 ... heat insulation layer, 4 ... lining layer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuyuki Sugiyama 1-3-1, Niihama, Arai-cho, Takasago, Hyogo Prefecture Harima Ceramic Co., Ltd. (72) Inventor Kenji Kitatani 1-3-3, Niihama, Arai-cho, Takasago, Hyogo Prefecture Harima Ceramics Co., Ltd. (72) Inventor Makoto Nakamura 1-3-1, Niihama, Arai-cho, Takasago, Hyogo Prefecture Harima Ceramics Co., Ltd. (56) Reference JP-A-2-77510 (JP, A) 164244 (JP, U) Actual development Sho 60-75899 (JP, U) Akira Nishikawa "Amorphous refractory-Pribrico's history-" (Sho 54-5-15) Nippon Puribrico Co., Ltd. P506-507

Claims (1)

(57) [Claims] 1. A thermal conductivity of 3.0 kcal / m · h · ° C. inside a steel skin provided with a large number of studs for pulling and supporting the lining layer.
A lining construction method for a blast furnace tap pipe cover, which comprises forming the following heat-insulating layer by spraying and then forming a lining layer comprising 40% by weight or more of the aggregate made of silicon carbide inside by casting.