JP2000192120A - Plugging material in iron tapping hole - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plugging material in an iron tapping hole for plugging the iron tapping hole in a blast furnace, excellent in the expandability to the width direction from the view point of the protection of a furnace wall and excellent in the closeness and the strength characteristic. SOLUTION: The plugging material in the iron tapping hole in this method, is composed of a powder part containing carbon block having 15-80 ml/100 g oil absorption of dibutyl phthalate(DBP) and pitch having 100-300 deg.C softening point and a binder of one or more kinds selected from a group composed of tar and resin base binder in a refractory aggregate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tap hole closing material used for filling a tap hole of a blast furnace to close the tap hole.

[0002]

2. Description of the Related Art As a tap hole closing material for closing a tap hole of a blast furnace, a refractory raw material containing a clay component and a sintering aid such as a metal are kneaded with an organic binder such as tar or phenol resin. Compositions are commonly used.

[0003] Techniques required for a blast furnace tap hole plugging material generally include good filling properties by a press-in machine, high bond strength at high temperatures, and excellent hot metal resistance. As described above, the clay component is usually used for the tap hole plugging material in order to keep the filling property by the press-fitting machine good. Here, when the compounding amount of the clay component is reduced, when the tapping hole plugging material is extruded from the filling machine to fill the taphole, it becomes difficult to extrude the taphole plugging material, and a good filling is performed. The problem arises that it becomes impossible to do so. However, when the clay component is added, it is necessary to increase the amount of binder such as tar, which leads to a decrease in strength at high temperatures or an increase in smoke at the start of tapping, thereby enabling stable tapping. It is not satisfactory in terms of environmental protection.

Japanese Unexamined Patent Publication (Kokai) No. 8-119754 discloses a tap hole plugging material characterized by containing not more than 3% by weight of a clay component and 2 to 20% by weight of carbon black. ing. That is, the tapping hole blocking material disclosed in this publication adds carbon black as an alternative to the clay component to reduce the amount of the clay component added. However, depending on the type of carbon black, it cannot be expected to reduce the amount of binder added. For example, when carbon black having a large oil absorption is blended, the amount of tar added increases as in the case where a large amount of a clay component is added, and improvement in strength properties and the like cannot be expected.

Further, Japanese Patent Application Laid-Open No. 10-36177 discloses that carbonaceous raw materials excluding carbon black raw materials are 5 to 25% by weight, silicon carbide is 5 to 50% by weight, silicon nitride based raw materials 10 to 10%.
45% by weight, dibutyl phthalate (DBP) oil absorption of 10
0 (ml / 100 g) or less carbon black raw material 2
Disclosed is a blast furnace tap hole plugging material characterized in that 100 parts by weight of a powder portion comprising 15% by weight and 15 to 75% by weight of a refractory raw material contains 10 to 25% by weight of a carbon-containing binder in an outer case. Have been. However, when a carbon black raw material having a dibutyl phthalate (DBP) oil absorption of 100 ml / 100 g or less is added, the expandability of the tap hole plugging material at the time of plugging differs from that of the clay component-containing tap hole plugging material in the lateral direction. Is poor in development and tends to expand in the straight traveling direction, poor in adhesion to old materials, and may cause problems from the viewpoint of furnace wall protection.

[0006]

As described above, a tap hole plugging material using a specific carbon black by reducing the addition of a clay component has a small amount of a binder to be added, is dense, and has excellent strength properties. However, it is poor in plasticity due to the reduction of clay components, expands in the straight direction when clogged, has poor expandability in the lateral direction, and lacks adhesion to old materials.

Accordingly, an object of the present invention is to provide a tap hole plugging material for plugging a blast furnace tap hole which is excellent in deployability in the lateral direction from the viewpoint of furnace wall protection, dense and excellent in strength properties. Is to provide.

[0008]

In order to solve the above-mentioned problems, the amount of binder such as tar is reduced, the material is dense, the strength is excellent, and the expandability in the lateral direction at the time of closing is improved. The present invention was completed by developing a taphole plugging material for furnace wall protection capable of forming a strong deposit.

That is, the present invention relates to a powder portion comprising a refractory aggregate containing carbon black having a dibutyl phthalate (DBP) oil absorption of 15 to 80 ml / 100 g and a pitch having a softening point of 100 ° C. to 300 ° C. And at least one kind of binder selected from the group consisting of tar and resin binders.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention relates to a refractory aggregate containing dibutyl phthalate (hereinafter referred to as "DBP") having an oil absorption of 15 to 80 ml / 1 as a powder portion constituting a taphole closing material.
00 g of carbon black 1 to 15% by weight, softening point 10
Excellent plasticity even when the amount of binder added is reduced by using a mixture obtained by adding and blending a pitch of 1 to 5% by weight at 0 to 300 ° C and a clay component of 6% by weight or less (preferably without a clay component). Further, it is possible to provide a taphole closing material excellent in deployability in a lateral direction when closed.

That is, the tapping hole blocking material of the present invention has a DBP oil absorption of 15 to 80 ml / 100 as an alternative to the clay component.
g of carbon black are used. If the DBP oil absorption of carbon black exceeds 80 ml / 100 g, the amount of binder added must be increased in order to impart suitable properties, and there is no point in replacing the clay component.

[0012] Here, carbon black has a term called "structure" which means a structure based on the connection or aggregation of particles, which is based on fusion, that is, a chemical bond or a physical property such as van der Waals force. It shows the cohesiveness of primary aggregates due to specific bonding. This highly cohesive carbon black (DBP oil absorption is 80 m
1/100 g) tends to increase the amount of tar added as a binder, similarly to the taphole plugging material to which the clay component is added, as shown in FIG.

FIG. 1 shows the amount of tar addition necessary to make the extrusion resistance (marshall value) of the tapping hole closing material about 350 kgf when carbon black having a different DBP oil absorption is added at 5% by weight. (Here, the amount of pitch added is 2% by weight, and the other powder parts have the same composition as Example 1 shown in Table 1 described below.)

Here, the reason why the extrusion resistance value is adjusted to about 350 kgf is that when the extrusion resistance value is 400 kgf or more, the slip property is poor, and the extrusion resistance value cannot be used in the actual furnace operation, and when the extrusion resistance value is less than 300 kgf. This is because, depending on the tapping hole closing material, the consistency may increase to 70 or more, and shape retention may not be secured. This extrusion resistance value was measured using a stainless steel sample holder (L1 = 9 cm, L2 = 6 cm, L
3 = 26cm, L4 = 12cm, L5 = 2cm), 6
The kneaded soil kept at 0 ° C. was filled, and a cylinder head (D) was measured using a measuring device shown in FIG. 3 (A: sample extruding face plate, B: sample holder, C: pedestal, D: cylinder head). ) Was measured as the total load applied to the sample extrusion face plate when the extrusion speed was 10 mm / sec.

As shown in FIG. 1, it is recognized that when the DBP oil absorption of carbon black is 80 ml / 100 g or less, the amount of tar added is clearly reduced. Therefore, in the tapping hole blocking material of the present invention, carbon black having a DBP oil absorption of 80 ml / 100 g or less is used, and more preferably a DBP oil absorption of 50 ml / 100 g.
The following carbon blacks. Further, the lower limit of the DBP oil absorption is 15 ml / 100 g, and if it is less than 15 ml, the cohesiveness of carbon black is small and the function as a substitute for the clay component is undesirably weak.

The DBP oil absorption is 15 to 80 ml / 1.
The amount of carbon black within the range of 00 g is 1 to
It is in the range of 15% by weight. Here, if the compounding amount of the carbon black is less than 1% by weight, it is not possible to secure slipperiness enough to substitute for a clay component, and
Exceeding the weight percent is not preferable because it hinders the sinterability of the structure of the taphole closing material and lowers the strength characteristics.

As an alternative to the clay component, a DBP oil absorption of 1
The tap hole plugging material using carbon black at 5 to 80 ml / 100 g has good slipperiness, but the expandability during plugging tends to go straight compared to the conventional tap hole plugging material containing a clay component. Therefore, from the viewpoint of furnace wall protection, which is one of the functions of the tap hole closing material, the adhesion to the old material is disadvantageous. This is compared to the conventional clay component-containing taphole plugging material.
The tapping hole plugging material using carbon black has low plasticity, poor expandability at the time of filling, poor adhesion to old material, and protrudes toward the furnace core, even if the same level of slip property is secured. Due to such a tendency, the spreadability in the lateral direction is poor, the adhesion to the old material is reduced, the deposition property on the furnace bottom is reduced, and the function of protecting the furnace bottom is reduced.

Therefore, in the tapping hole plugging material of the present invention, a pitch is added and used in order to enhance the expandability in the lateral direction. Since the pitch softens in the operating temperature range of the tap hole plugging material, the tap hole plugging material added with the pitch has excellent spreadability in the lateral direction, good adhesion with the old material, Is also good, and stable deposits in the furnace can be formed. The pitch used in the present invention has a softening point in the range of 100 to 300 ° C. here,
If the softening point of the pitch is lower than 100 ° C, the tapping hole blocking material softens in the mud gun before the tapping hole is closed, and the plugging property decreases, leaking from the gap between the mud gun and the tapping hole and sufficient blocking effect. Is not preferred because it cannot be performed.
Also, if the softening point of the pitch exceeds 300 ° C., it does not soften within the closing operation time, the effect of adding and using the pitch is small, it expands in the straight direction, has poor adhesion to the old material, and has a strong deposit. Is not formed.

The amount of pitch having a softening point in the range of 100 to 300 ° C. is 1 to 5% by weight. If the added amount of the pitch is less than 1% by weight, the effect of adding the pitch cannot be sufficiently exerted. If the added amount exceeds 5% by weight, the porosity increases because the sintering of the refractory aggregate is suppressed. It is not preferable because it is not possible to obtain excellent strength characteristics.

The refractory aggregate constituting the powder portion of the tap hole plugging material of the present invention contains 5 to 50% by weight of a silicon carbide raw material, 5 to 45% by weight of a silicon nitride raw material, and 10 to 50% by weight of an alumina raw material. It is desirable to use in the ratio of.

Further, as other refractory aggregate, it is also possible to use an oxide material such as lozenge, mullite, spinel, zircon, zirconia, magnesia, etc., and these may be used alone or in combination of two or more. good. When these refractory aggregates are used, it is desirable that the amount added be 10% by weight or less. If the addition amount of these refractory aggregates exceeds 10% by weight, the addition amount of the main refractory aggregates is reduced, which is not preferable.

Further, the tapping hole plugging material of the present invention may be allowed to contain a clay component in an amount of 6% by weight or less for ensuring slipperiness. Here, if the addition and blending amount of the clay component exceeds 6% by weight, the amount of the binder added is undesirably increased. In addition, as the clay component, for example, Kibushi clay, ball clay, frog eye clay and the like can be used.

The tapping hole closing material of the present invention comprises a powder portion having the above-mentioned composition and a binder. Tar or resin binders can be used as the binder. The amount of the binder to be added is 8 to 17% by weight based on the powder part, more preferably 1 to 17% by weight.
1 to 15% by weight. The tar has a high viscosity (50
It is preferable to use one having a viscosity at 1000C of 1000 to 5000 cPs and a residual carbon ratio of 30% or more. As the resin binder, for example, a resol type or novolak type phenol resin can be used.

[0024]

EXAMPLES Examples and comparative examples are shown below to further describe the tapping hole blocking material of the present invention. Example A composition as shown in Table 1 was prepared, the obtained composition was kneaded for about 5 minutes, and then tar was added as a binder and kneaded for about 30 minutes. The kneading temperature is 60 ° C.
Here, tar has a viscosity of 2000 cPs at 50 ° C. and a residual carbon ratio of 33%. The amount of tar added was adjusted to be about 350 kgf (total load by the tester shown in FIG. 3) by extrusion resistance measurement (Marshall test). The shape retention was measured by using a penetration tester described in JIS K2220 and measuring the length of penetration of a needle having the shape shown in FIG. 4 in 5 seconds. In addition, 60 ° C
When the consistency exceeds 80, the shape retention is low. When the consistency is less than 50, the shape retention is not a problem, but the expandability at the time of filling tends to go straight, and there is a problem in the formation of a furnace bottom deposit. Therefore, the consistency at 60 ° C. is preferably from 50 to 70.

Next, at a molding pressure of about 5 MPa, 40 × 40 ×
After bending to 160 mm and reducing heat at 1350 ° C. for 3 hours, the sample was measured for flexural strength and apparent porosity. FIG. 5A schematically shows an apparatus used for evaluating the deployability of the tap hole closing material at the time of closing. A coke (5) having a particle size of 10 to 30 mm is charged into a heating furnace (8) which can be divided vertically into two parts, and the temperature is raised to about 1500 ° C. while blowing combustion air (4) from the lower part. Using a hydraulic machine composed of (6) and a hydraulic cylinder (2), the sample (the tap hole plugging material: 1) is charged into the furnace at about 1 kg / time. After the filling operation was repeated three times at intervals of 10 minutes, the opening was sealed and naturally cooled to room temperature. Then, the furnace was divided into two parts, and the distribution state of the tap hole plugging material was compared and investigated. The distribution at filling was evaluated by dividing the length in the straight direction by the length in the horizontal direction as shown in the following equation:

## EQU1 ## Developability = 2.times.straight direction (Z) / [horizontal horizontal direction (X) + vertical horizontal direction (Y)] Here, for the filled sample, horizontal horizontal direction (X), vertical horizontal direction (Y) ) And the straight traveling direction (Z) are as shown in FIG. In other words, it is evaluated that the larger the numerical value, the straighter the tendency to expand, and the smaller the numerical value, the easier it is to expand in the horizontal direction. Table 1 also shows the obtained results.

[0026]

[Table 1]

As shown in Comparative Example 1, the clay component, DBP
Those having no oil black in the range of 15 to 80 ml / 100 g to which carbon black and pitch are not added, have poor slipperiness, and it is necessary to increase the amount of tar added to secure an extrusion resistance value of 350 kgf. Becomes larger,
Sufficient shape retention cannot be ensured.

Further, as shown in Comparative Example 2, when the clay component was added in an amount of about 10% by weight in order to secure the slipperiness, 20% by weight was added on the outside in order to obtain a predetermined extrusion resistance value. Excess tar must be added, resulting in high apparent porosity and reduced flexural strength.

Example 1 in which 5% by weight of carbon black having a DBP oil absorption of 30 ml / 100 g and 2% by weight of pitch were added, and Example 2 in which 10% by weight of carbon black having a DBP oil absorption of 30 ml / 100 g and 2% by weight of pitch were added.
Has sufficient lubricity, has a tar content of 12 to 13% by weight (outer shell), and has a DBP oil absorption of 15 to 80 ml / 10
In the range of 0 g, the carbon black and the pitch can be reduced as compared with no addition (25% by weight), the flexural strength increases to 19 to 20 MPa, and the apparent porosity decreases to 17%. By adding carbon black and pitch having a DBP oil absorption within the range of 15 to 80 ml / 100 g without adding the clay component, the binder addition amount can be reduced without lowering the slipperiness. The porosity can be reduced and the bending strength can be increased.

Also, in Example 3 in which 5% by weight of carbon black having a DBP oil absorption of 30 ml / 100 g and 4% by weight of pitch were added, the amount of tar added was reduced as in Example 1, and the flexural strength was sufficiently 19 MPa. Characteristic.

Also in Example 4 in which 5% by weight of carbon black having a DBP oil absorption of 80 ml / 100 g and 2% by weight of pitch were added, the added amount of tar was reduced to 13% by weight, and the flexural strength was 18 MPa, showing sufficient characteristics. ing.

However, as in Comparative Example 3, the DBP oil absorption 3
When 20% by weight of 0 ml / 100 g of carbon black is added, the amount of tar added and the strength properties are reduced as compared with the case where 5% by weight of the carbon black is added. It turns out that 15 weight% or less is suitable.

Further, as in Comparative Example 4, the DBP oil absorption 11
When 5% by weight of 0 ml / 100 g of carbon black is added, the amount of tar added increases, the porosity increases, the strength characteristics decrease, and the effect of reducing the clay component decreases, as in the case of adding the clay component. The carbon black to be added preferably has a DBP oil absorption of 80 ml / 100 g or less, since the carbon black is diluted.

Further, as in Embodiments 5 and 6, D
In the case of adding 2% by weight or 6% by weight of a clay component together with 5% by weight of carbon black having a BP oil absorption of 30 ml / 100 g and 2% by weight of pitch, the sliding property was maintained as in Examples 1 and 2. The amount of tar added can be reduced as it is, the porosity decreases, the flexural strength also increases, the clay component in an amount of 6% by weight or less and the DBP oil absorption 15 to
It turns out that it is also possible to simultaneously add 80 ml / 100 g of carbon black. However, if the clay component is 6
If it exceeds 10% by weight, the DBP oil absorption is 15 to 80 ml / 10
Even when 0 g of carbon black is used in combination, the amount of tar cannot be reduced, and the effect of adding the carbon black is not exhibited. Therefore, DBP oil absorption 15-80m
When 1/100 g of carbon black and a clay component are added simultaneously, the amount of the clay component added is preferably 6% by weight or less.

Next, the effect of the pitch addition will be described using a comparative example. The consistency suitable for the conditions of use as taphole plugging material is in the range of 80 to 100 at 120 ° C. If the consistency is less than 80, the material is poor in plasticity and the adhesion to the old material is low, which is not desirable. Also, if the consistency is 1
If it exceeds 00, it will be soft and cause mud wetting when closed,
It is not preferable because there is a high possibility that sufficient filling cannot be performed.

As shown in Comparative Example 5, when no pitch was added, the consistency was small and the plasticity was low. That is, since the consistency at 120 ° C. is less than 80, the tap hole plugging material is hard at the time of plugging,
There is a possibility that a strong sediment cannot be formed on the furnace bottom because it easily spreads in the straight direction and has low adhesion to the old material. Further, as shown in Comparative Example 6, when 8% by weight of the pitch was added,
High consistency (consistency at 120 ° C. exceeds 100),
There is a high possibility that mud leakage will occur due to excessive softening in the mud gun during use.

[0037]

According to the tapping hole closing material of the present invention, carbon black having a DBP oil absorption of 15 to 80 ml / 100 g is used in an amount of 1 to 1 carbon black.
By adding and blending 5% by weight and pitch of 1 to 5% by weight, and making the clay component 6% by weight or less, the tar content is reduced, the density is increased, the strength properties are increased, and the furnace bottom is protected. From the viewpoint, the deployability in the lateral direction at the time of closing can be improved.

[Brief description of the drawings]

FIG. 1 is a graph showing the amount of tar addition necessary for adjusting the extrusion resistance value of a tapping hole closing material to about 350 kgf when carbon black having various DBP oil absorptions is added at 5% by weight.

FIG. 2 is a view showing a stainless steel sample holder for measuring an extrusion resistance value.

FIG. 3 is a diagram illustrating an apparatus for measuring an extrusion resistance value.

FIG. 4 is a diagram illustrating the shape of the needle of the penetration tester.

FIG. 5 (a) is a view showing an apparatus for measuring the expandability of a tap hole plugging material, and FIG. 5 (b) is a view showing a horizontal lateral direction (X) of a filled sample used for determining the expandability. ), A vertical horizontal direction (Y), and a straight traveling direction (Z).

[Explanation of symbols]

 A Sample Extrusion Faceplate B Sample Holder C Pedestal D Cylinder Head 1 Sample 2 Hydraulic Cylinder 3 Filled Sample 4 Combustion Air 5 Coke 6 Hydraulic Pump 7 Thermocouple 8 Heating Furnace

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tatsuya Kageyama 2-2-1 Otemachi, Chiyoda-ku, Tokyo Shinagawa White Brick Co., Ltd. (72) Masafumi Kitamura 2--2 Otemachi, Chiyoda-ku, Tokyo No.1 item Kawashira Brick Co., Ltd. F term (reference) 4G033 AA02 AA17 AA19 AB01 AB07 AB21 AB25 BA01 4K055 AA01 JA15

Claims (4)

[Claims] 1. A refractory aggregate comprising dibutyl phthalate (DB)
P) One or two types selected from the group consisting of a powder portion containing carbon black having an oil absorption of 15 to 80 ml / 100 g and a pitch having a softening point of 100 ° C to 300 ° C, and a tar and a resin binder. A tapping hole closing material comprising the binder described above. 2. The tap hole plugging material according to claim 1, wherein the content of carbon black is 1 to 15% by weight and the content of pitch is 1 to 5% by weight. 3. The tap hole closing material according to claim 1, wherein the content of the binder is 8 to 17% by weight based on the powder portion. 4. The tap hole plugging material according to claim 1, which comprises a clay component in an amount of not more than 6% by weight.