JPH07115955B2 - Blast furnace tap closure - Google Patents

Description

TECHNICAL FIELD The present invention relates to a blast furnace taphole closing member.

Conventional technology and its problems With the recent increase in size of blast furnace and severer operating conditions, corrosion resistance (slag resistance), heat resistance, wear resistance, etc. of tapping plug clogging material against hot metal and slag Improvement is strongly desired.
In particular, if the slag resistance is low, the amount of slag in the latter half of the tapping increases, causing rapid wear and expansion of the taphole, and a large amount of in-furnace gas leaks from the enlarged taphole together with the hot metal and slag. , The tap hole must be closed again before tapping is performed sufficiently. Such reduction of tapping time is
Inevitably, the number of tapping times is increased, the tapping operation efficiency and workability are markedly reduced, and the tapping work load increases and the production amount decreases due to unstable operation.

In order to solve the above-mentioned problems, attempts have been made to improve the slag resistance by increasing the residual carbon rate of liquid organic binders such as coal tar. In order to increase the residual coal rate of coal tar, the pitch component should be increased. However, when the pitch component exceeds a certain amount, the clay of the binder rises remarkably, the respective components do not mix sufficiently uniformly during the production of the plugging material, and the workability becomes extremely poor.
As a solution to such a drawback, a liquid organic binder containing a phenol resin as a main component, for example, a solution obtained by dissolving a phenol resin in diethylene glycol is used. However, since 1) the boiling point of diethylene glycol is relatively low at 244.3 ° C in this binder, the plugging material hardens rapidly when the tap hole is plugged, and the volatilization of volatile components falls within a narrow temperature range. Since it concentrates, there is a problem that it is not possible to sufficiently cover the irregular asperity and crack damage part of the furnace wall in the hole, and the original characteristic of phenol resin, that is, the characteristic that the residual carbon rate is high is fully exhibited. Has not reached. Moreover, since diethylene glycol has hygroscopicity, it is difficult to store the occlusive material using this binder for a long period of time.

Means for Solving the Problems The present inventor has conducted extensive studies in view of the problems of the above-mentioned conventional techniques, and as a result, as a plugging material having a specific composition, a thermosetting phenolic resin and decrystallized anthracene oil and / or By adding a liquid organic binder consisting of creosote oil,
1) High residual coal rate 2) Rapid hardening does not occur when the tap hole is closed, and it is possible to sufficiently cover irregular irregularities and crack damages on the tap wall inner wall 3) Serviceability The present invention has been completed based on the finding that an occlusion material that can remarkably improve the strength and strength and 4) can further stabilize the workability can be obtained.

That is, the present invention relates to (a) carbon raw material 60 to 84% by weight, silicon carbide 5 to 15% by weight, carbon black 4 to 15% by weight, metallic silicon 2 to 8% by weight, and Al ₂ O ₃ —SiO ₂ based carbonized bone. A liquid organic binder comprising 100 parts by weight of a plugging material raw material composed of 5 to 20% by weight and (b) 60 to 90% by weight of a phenol resin and 10 to 40% by weight of decrystallized anthracene oil and / or creosote oil 15 ~
This relates to a blast furnace taphole closing material containing 20 parts by weight.

In the present invention, carbon materials, silicon carbide,
Carbon black, metallic silicon and Al ₂ O ₃ —SiO ₂ type refractory aggregate are used.

As the carbon raw material, any of ordinary carbon raw materials other than carbon black can be used, and examples thereof include earth-like graphite, scaly graphite, coal coke, petroleum coke, and electrode pulverized products. The amount of the carbon material blended is preferably about 60 to 84% by weight in the plugging material. If it is less than 60% by weight, the slag resistance of the obtained blocking material is not sufficient, while if it exceeds 84% by weight, the strength of the obtained blocking material is lowered.

Any ordinary silicon carbide can be used. The compounding amount of silicon carbide is preferably about 5 to 15% by weight in the plugging material. Outside the above range, the slag resistance and strength are reduced, which is not preferable.

The particle diameters of the carbon material and silicon carbide are not particularly limited and may be appropriately selected. For example, particles of about 3000 to 500 μm and particles of about 210 μm or less may be mixed in appropriate amounts and used.

Carbon black is effective in improving the plasticity and bondability and slag resistance of the occluding material. The carbon black is not particularly limited, and any ordinary carbon black can be used, and examples thereof include channel black, furnace black, and acetylene black produced by incompletely burning hydrocarbons. The particle size of carbon black is not particularly limited and may be appropriately selected, but the average particle size is usually about 74 μm or less. If it exceeds 74 μm, the cohesive force is reduced, and the plasticity suitable for filling the taphole may not be obtained in some cases. The compounding amount of carbon black is preferably about 4 to 15% by weight in the raw material of the occluding material. Below 4% by weight,
The characteristics of carbon black are not sufficiently exhibited, while if it exceeds 15% by weight, the plasticity becomes too large, and it becomes difficult to fill the taphole.

Metallic silicon reacts with CO gas generated by oxidation of a carbon-based raw material to generate silicon carbide (β-SiC) and SiO ₂ , and mainly reacts with carbon black in a temperature range of about 1100 to 1500 ° C. Exerts a strong binding force and improves strength and slag resistance. The SiO ₂ liberated during the generation of silicon carbide suppresses the excessive generation of CO gas and densifies the structure. The compounding amount of metallic silicon is preferably about 2 to 8% by weight in the raw material of the plugging material. If it is less than 2% by weight, the above effect is not exerted, while on the other hand, 8
If the content is more than weight%, the strength becomes excessive and it becomes difficult to open the tap hole.

Al ₂ O ₃ -SiO ₂ -based carbonized aggregate is mainly melted and softened in a high temperature range of 1500 ° C. or higher to have fluidity, and β-SiC produced by the reaction of this melt and carbon black with a carbon raw material. And SiO ₂
And are mixed to densify the structure of the occluding material, which is effective for improving the slag resistance and suppressing the oxidation of the occluding material component. Al ₂ O ₃ -SiO
_{The 2} type refractory aggregate is not particularly limited, and ordinary one can be used, for example, Al ₂ O ₃ content of about 10 to 20%, SiO ₂ content of 75
To about 85%, Al ₂ O ₃ content of about 85 to 95%, SiO ₂ content of about 5 to 10%, and the like. Al ₂ O ₃ −S
The amount of iO ₂ -based refractory aggregate is 5 to 20% by weight in the raw material of the plugging material.
It is good to set the degree. If it is less than 5% by weight, there is no effect of suppressing the oxidation of the occluding material in the high temperature range, while if it exceeds 20% by weight, the slag resistance is lowered.

In the present invention, a liquid organic binder containing a phenol resin as a main component and decrystallized anthracene oil and / or creosote oil as a solvent is used. This liquid organic binder hardens from around 300 ° C, volatilization of volatile components does not concentrate in a narrow temperature range, and it spreads over a wide temperature range of about 235 to 360 ° C, so it maintains fluidity. It takes a long time, the number of pores is small, and the pore diameter is small. Moreover, since a large amount of phenol resin can be added, the residual carbon rate can be increased, and the slag resistance and strength can be improved. As the phenol resin, a usual thermosetting resol-type phenol resin can be used, and examples thereof include those in which the solvent is phenol.
The compounding amount of the phenol resin is preferably about 60 to 90% by weight in the liquid organic binder. As the decrystallized anthracene oil and creosote oil, any ordinary one can be used.
The amount of decrystallized anthracene oil and / or creosote oil is preferably about 10 to 40% by weight in the liquid organic binder. If it is less than 10% by weight, there is no effect of suppressing the rapid hardening of the plugging material when the taphole is blocked, while if it exceeds 40% by weight,
Improvement of slag resistance and strength becomes insufficient.

The blending amount of the liquid organic binder is preferably about 15 to 20 parts by weight with respect to 100 parts by weight of the occluding material. If the amount is less than 15 parts by weight, the respective components of the occluding material are not uniformly mixed at the time of production, and the plasticity necessary for pushing with the gun when the tap hole is closed cannot be obtained.
On the other hand, if it exceeds 20 parts by weight, the fluidity becomes excessive and the structure becomes non-uniform, and the slag resistance and the strength deteriorate. In addition, the clogging of the tap hole is insufficient, which is not preferable.

The occlusive material of the present invention is produced by mixing the predetermined amounts of the above-mentioned components by a conventional method in this field.

In closing the tap hole of the blast furnace using the plugging material of the present invention, any of the usual plugging methods in this field can be adopted.

EFFECTS OF THE INVENTION The plugging material of the present invention has 1) a high residual carbon rate, and 2) does not undergo rapid hardening when the taphole is blocked, so that irregular irregularities and crack damages on the taphole inner wall are prevented. It can be sufficiently covered, and 3) it is extremely excellent in slag resistance and strength, and 4)
Stabilize workability.

Examples The following examples and comparative examples will further clarify the present invention. Tables 1 to 4 show the chemical components of the raw materials used in the examples. As for metallic silicon, the Si content is 97.5%.
I used the one.

Examples 1 to 3 and Comparative Examples 1 and 2 At the blending ratio shown in Table 5, a liquid organic binder was added to 100 parts by weight of the occluding material and kneaded well, and the occlusive material of the present invention ) And a conventional occlusive material (Comparative Examples 1 and 2). The various blocking materials thus obtained were molded, subjected to a push-and-fill test at 600 ° C. into the taphole, then fired at 1400 ° C., and then subjected to a performance test. The results are shown in Table 5.

The linear expansion and contraction conform to JIS R-2576, and the apparent porosity is JIS
According to R-2205, compressive strength was measured according to JIS R-2575. The slag resistance was expressed as 100 in Example 1.

It can be seen from Table 5 that the product of the present invention has remarkably excellent slag resistance and strength as compared with the conventional product, and the filling degree is also superior to the conventional product.

When the product of the present invention (Example 2) and the conventional product (Comparative Example 2) were used to block the tap hole of the large-scale blast furnace of Company A (4500 m ³ ), the conventional product showed a tapping time of 165 to 217 minutes and an average output. Pig time 195 minutes,
While the average taphole length was 2950 mm, in the product of the present invention, the tapping time is 198 to 236 minutes, the average tapping time is 220 minutes, the average tapping length is 3200 mm, and the workability is remarkable. Stable. Further, from this, it becomes clear that the filling degree of the present invention is improved and the covering property of the taphole inner wall is increased.

Claims (1)

[Claims] (A) 60 to 84% by weight of carbon material, 5 silicon carbide
15 wt% of carbon black 4-15 wt%, 2-8 wt% silicon metal and Al2O ₃ -SiO ₂ refractory aggregate 5-20 wt%
Liquid organic binders 15 to 20 consisting of 100 parts by weight of a occluding material as a raw material and (b) 60 to 90% by weight of a phenol resin and 10 to 40% by weight of decrystallized anthracene oil and / or creosote oil
Blast furnace taphole closing material containing parts by weight.