JP2000319711A - Mud material for iron tapping hole in blast furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mud material for iron tapping hole which has excellent corrosion resistance, strength, or the like, and can easily be opened. SOLUTION: Refractory aggregate of the mud material has a composition containing 10-80 wt.% silicon carbide, 5-40 wt.% agalmatolite and 5-30 wt.% carbon, and in 100 wt.% of the refractory aggregate, 10-70 wt.% of the silicon carbide is regulated to have grain diameter of 5-3 mm, and 5-15 wt.% of the agalmatolite is regulated to be superfine powder having <=5 μm average grain diameter. Further, to 100 wt.% of the refractory aggregate, <=40 wt.%, by the outer ratio of the silicon nitride. iron (Si3N4.Fe) is added.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mud material used for closing a blast furnace taphole (hereinafter, simply referred to as a mud material).
It is about.

[0002]

2. Description of the Related Art In recent years, as blast furnaces have become larger and operating conditions have become more severe, the load on mud materials has increased. In addition to mud materials, there is a demand for measures to reduce energy consumption and unit cost and to reduce labor by reducing the number of workers in front of the furnace.

It is known to add fine powdered silicon carbide to the matrix portion of a mud material structure in order to improve the corrosion resistance and wear resistance of the mud material (for example, Japanese Patent Publication No.
No. 44-13026). Further, silicon nitride, silicon iron nitride, metals, and the like are added for further improving corrosion resistance, wear resistance, and peeling resistance.

[0004]

The mud material has corrosion resistance,
In addition to abrasion resistance and the like, ease of opening during tapping is required.
Conventional mud materials are excellent in corrosion resistance, hot strength and sintering strength, but excessive strength development causes a decrease in porosity.

[0005] As a result, a considerable amount of time is required for the opening operation,
The hole or the hole for opening was deformed by the heat and sometimes melted, so that the opening operation was not easy. Further, it is not preferable in that the peel resistance is reduced.

[0006] Siliceous raw materials known as one of the refractory aggregates of mud materials are refractory raw materials having relatively low particle strength. Therefore, it is conceivable to improve the porosity by increasing the amount of the siliceous raw material.However, when the siliceous raw material increases, the corrosion resistance and wear resistance decrease, and it is difficult to secure a sufficient tapping time. Become.

An object of the present invention is to provide a mud material which can be easily opened and has excellent corrosion resistance, abrasion resistance and peeling resistance.

[0008]

SUMMARY OF THE INVENTION The present invention combines a silicon carbide raw material having high corrosion resistance to hot metal and slag, and a rock which is effective in enhancing the wear resistance and peeling resistance of the matrix portion. As a result of examining the use particle size and the abundance ratio, a mud material having the intended characteristics was obtained.

The characteristics of the mud material of the present invention are as follows.
As refractory aggregate, silicon carbide 10-80 wt%, limestone 5-40
wt%, 5-30 wt% carbon, and the refractory aggregate
10 to 70% of the silicon carbide in a proportion of 100 wt%.
wt% with a particle size of 5 to 3 mm;
In this case, wt% is defined as an ultrafine powder having an average particle size of 5 μm or less.

[0010] The inventors of the present invention have proposed a technique for improving the porosity.
The idea was to use the chips of the material generated at the time of opening as the abrasive. For that purpose, a raw material having a high hardness that can be used as an abrasive must be used. In addition, in order to suppress hot strength, which is an adverse effect of porosity, and to impart corrosion resistance and peeling resistance, it is necessary to use a raw material that is difficult to sinter,
Further, it is necessary to provide the matrix portion with a bonding strength that does not cause the material to flow away at the time of tapping.

Conventionally, refractory aggregates used for mud materials include alumina, alumina-silica, silica, high alumina, magnesia, magnesia-calcia, spinel, carbide, nitride, carbon, coke, clay and metal. And so on. Among them, those having high hardness include alumina, high alumina, and silicon carbide. However, alumina and high-alumina raw materials have high hot strength of mud material,
The property of high hardness is offset, and as a result, the effect of improving the porosity cannot be obtained.

On the other hand, silicon carbide has a very high hardness, and is generated as chips at the time of opening, and silicon carbide itself acts as an abrasive. Moreover, since silicon carbide is a material that is difficult to sinter, the development of hot strength is suppressed. As a result, it effectively works to improve the porosity. In addition, since silicon carbide essentially has slag penetration resistance and slag resistance, it also exhibits excellent effects in improving the corrosion resistance and wear resistance of the mud material.

However, since silicon carbide is difficult to sinter, the peeling resistance of the mud material during tapping is reduced. In this regard, in the present invention, by combining the matrix portion and the aggregate by using a combination of the ultrafine powder of limestone, it is possible to prevent the loss of the aggregate at the time of tapping, which causes a decrease in peeling resistance. In addition, since silicon carbide is hardly sinterable, oversintering does not occur even when a combination of ultrafine stones is used, and the effect of the porosity is not impaired.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, if the proportion of silicon carbide in the refractory aggregate is less than 10% by weight, the effect of porosity cannot be remarkably obtained, and if it exceeds 80% by weight, the effect of peeling resistance is poor.

The silicon carbide is used as coarse particles having a particle size of 5 to 3 mm in an amount of 10 to 70 wt% based on 100 wt% of the refractory aggregate. The proportion of silicon carbide having a particle size of 5 to 3 mm is 10 wt%.
If it is less than 1, silicon carbide does not sufficiently act as an abrasive at the time of opening, so that the opening property is poor. If the proportion of silicon carbide having a particle size of 5 to 3 mm exceeds 70 wt%, the sintering resistance is promoted, and the wear resistance and the peeling resistance are reduced. As a result, the tapping time is shortened and the effect of the present invention is obtained. Can not be obtained.

The pyroxene is pyrophyllite, sericite,
It is a refractory raw material mainly containing kaolin and quartz, and has an effect of bonding silicon carbide and a matrix part with moderate strength.
Pyroxene is 5 wt% in proportion to 100 wt% of refractory aggregate.
When the amount is less than the above, the effect of the binding property is not exerted, and the porosity is poor.

[0017] In the pyroxene, the average particle size is 5 μm or less in the proportion of 5 to 15 wt% in the proportion of 100 wt% of the refractory aggregate, and the proportion of the pyroxene in the total of 100 wt% of the refractory aggregate is 5%.
4040 wt%. If the proportion of the average particle size of 5 μm or less is less than 5 wt% with respect to the entire refractory aggregate, the effect of the porosity of the pyrophyllite cannot be obtained. Becomes porous and causes a decrease in corrosion resistance.

In this case, the average particle diameter can be specified by, for example, particle diameter measurement by a laser diffraction method.

Carbon has the effect of improving the permeability of the mud material and speeding up its sintering. Specific examples of the material include coke, carbon black, graphite, and the like.

Carbon is 5 to 100% by weight of the refractory aggregate.
30 wt% is blended. If the addition amount is less than 5 wt%, sintering is not performed quickly and the tapping hole blocking function is inferior. If the addition amount exceeds 30 wt%, the corrosion resistance decreases.

In the present invention, the above-mentioned refractory aggregate is essential, but other materials such as alumina and clay may be combined.

For example, alumina is effective in improving the corrosion resistance, but excessive addition of alumina increases the number of cuts.
The appropriate ratio is 40 wt% or less on an inner scale. Clay is effective in imparting plasticity to the material and speeding up the filling operation. However, since the use of a large amount causes a decrease in corrosion resistance, the ratio is desirably 3 to 20% by weight.

In addition to the above, the mud material of the present invention may contain metal silicon, Fe-Si, silicon nitride, silicon nitride iron, or the like as long as the effects of the present invention are not impaired. For example, silicon iron nitride (Si ₃ N ₄ .Fe) is added in a range of not more than 40 wt% on the basis of 100 wt% of the refractory aggregate.

In the present invention, the pyroxene binds the silicon carbide and the matrix portion with a moderate strength. However, it cannot be denied that the corrosion resistance tends to decrease as the amount of addition increases. In this regard, the addition of silicon iron has the effect of preventing a decrease in corrosion resistance when the amount of added rock is increased, without impairing the bonding effect of the rock made of iron with moderate strength.

In the case where silicon iron nitride is added, the proportion thereof is set to 40 wt% or less, more preferably 1 to 30 wt%, on the basis of 100 wt% of the refractory aggregate. Addition ratio is 40wt%
Exceeding the temperature is not preferable because the development of the strength becomes extremely large and the porosity during tapping deteriorates. The particle size is not particularly limited, but is preferably 0.5 mm or less.

The type of the binder and the proportion thereof are not particularly different from those of the prior art. For example, tar, tall oil, heavy oil, phenolic resin, etc. can be used, and the addition ratio thereof is 100% for refractory aggregate.
It is desirable that the weight ratio is 10 to 40% by weight.

[0027]

EXAMPLES Examples of the present invention and comparative examples will be described below with reference to Table 1.

Table 1 shows the composition and test results of the examples of the present invention and comparative examples. In each example, the following tests were carried out after kneading the materials with the composition shown in Table 1. .

Hot bending strength: Test pieces obtained by forming a specimen to a size of 40 × 40 × 160 mm and then drying were measured for bending strength at 1000 ° C. and 1200 ° C. to determine the strength of the mud material. Tested.

Opening property: The tap hole of a blast furnace of more than 5000 m ³ is approximately 3
It was closed with a mud material of 00 kg and actually opened. Drilling was performed with a drill and a drill as usual, and evaluation was made by the ease of drilling work.

Tapping time: The interval from the opening to the next blockage was defined as the tapping time. The diameter of the tap hole after opening gradually increases due to the flow of pig iron, and if the diameter becomes too large, it becomes difficult to close the tap hole. The longer the time until the blockage is, the better the corrosion resistance, peeling resistance and the like.

[0032]

[Table 1]

As shown in the test results shown in Table 1, all the mud materials of the examples of the present invention were excellent in hole opening easiness, and the tapping could secure a long time exceeding 160 minutes. It can be seen that among the examples of the present invention, the material added with silicon iron nitride has a longer tapping time and is excellent in durability.

On the other hand, Comparative Example 1, in which only silicon carbide is fine powder, is inferior in porosity because silicon carbide does not show a sufficient effect as an abrasive at the time of piercing. In Comparative Example 2, the hot-bending strength was insufficient and the peeling resistance was inferior because of not using the ultrafine stone, and a sufficient tapping time could not be secured.

In Comparative Example 3, the proportion of the ultrafine pyroxene was too large, and the amount of silicon carbide having a particle size of 5 to 3 mm was small, resulting in inferior porosity and short tapping time. In Comparative Example 4 in which the amount of silicon carbide having a particle size of 5 to 3 mm was too large, the hot strength was significantly reduced, and the tapping time was not sufficient. The tapping time is also short for Comparative Example 5 in which the proportion of the entire pyrophyllite is too large.

In Comparative Example 6, although iron silicon nitride was added, the tapping time was short because the proportion of the entire pyrophyllite was too large.

[0037]

As described above, according to the present invention, the drilling workability is significantly improved by imparting hardness that can be used as an abrasive to the chips of the mud material, resulting in a delay in the drilling operation. It can be done quickly without. In addition, the tapping time can be extended due to excellent corrosion resistance, peeling resistance, and the like, and as a result, tapping work becomes more efficient.

Claims (2)

[Claims] 1. As a refractory aggregate, silicon carbide 10 to 80 wt.
%, 5 to 40 wt% of rock, and 5 to 30 wt% of carbon, and 10 to 70 wt% of the silicon carbide has a particle size of 5 to 3 mm in a proportion of 100 wt% of the refractory aggregate. A blast furnace taphole mud material of which 5 to 15 wt% is ultrafine powder having an average particle size of 5 μm or less. 2. The refractory aggregate of 100 wt% of the above composition is further coated with silicon iron nitride (Si ₃ N ₄ .Fe) 40 watts.
The mud material for a blast furnace taphole according to claim 1, wherein t is added in an amount of not more than t%.