JPH111373A - Mad material for tap hole - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an inexpensive mad material for tap hole, excellent in high early-strength property and corrosion resistance (high-temperature strength) and having good thermal stability without causing burning. SOLUTION: In this mad material for tap hole obtained by compounding refractory aggregate such as alumina, agalmatolite, chamotte, silicon carbide with a carbonaceous raw material such as coke or graphite, fire clay such as kaolin or bentonite and a binder, the binder comprises a mixture of coal particles with a fraction component having 100-450 deg.C boiling point in coal tar and the fraction component having 100-450 deg.C boiling point is one or more substances selected from naphthalene absorbent oil, tar absorbent oil, anthracene oil, anthracene oil freed from crystal, benzene, toluene, xylene and phenols or a hydrocarbon containing >=20 wt.% aromatic compound whose condensed ring is tricyclic or tetracyclic and carbon content of coal particles is preferably 78-90 wt.%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a taphole mud material excellent in early strength and corrosion resistance used for a taphole of a blast furnace, a shaft furnace, or the like.

[0002]

2. Description of the Related Art In recent years, in order to improve the work efficiency in front of a blast furnace, to save labor in front-of-furnace work, to reduce furnace-turning equipment and repair costs, etc., tapping is performed for a long time from one tap hole. Continuous tapping operation is drawing attention.

[0003] In order to realize this continuous tapping operation, crimping and holding time of a mud gun against a tapping mud material (also referred to as filler) can be reduced, and even if tapping is performed for a long time. It is required as an essential requirement (basic characteristics) that the tapping diameter is small and the tapping speed can be maintained stably.

[0004] In order for the taphole mud material to satisfy the above requirements, it is required that after filling into the taphole, it is quickly fired and solidified to exhibit strength. This rapid firing, solidification, and strength development in this relatively low temperature range (below 300 ° C) is called early strength. Further, in order to satisfy the above, it is required that the high-temperature strength is high and the steel has excellent corrosion resistance to hot metal and slag. Here, the high temperature strength is 400 ° C
The strength in the above temperature range serves as a measure, and the higher the high-temperature strength, the higher the corrosion resistance.

On the other hand, conventionally, mud materials have been prepared by mixing refractory aggregates such as alumina, laurite, chamotte, and silicon carbide with carbonaceous materials such as coke and carbon and refractory clay such as kaolin and bentonite. Used with a binder. For example, those using a tar-based binder to which coal tar, pitch, etc. are added (hereinafter referred to as a tar-based mud material), and those using a synthetic resin such as a phenol resin as a binder in recent years (hereinafter, referred to as a phenol-based mud material) Is also commonly used.

Recently, it has been proposed to add coal tar or cutback pitch and expandable or weakly caking coal as binders to conventional refractory materials. For example, Japanese Patent No. 2,592,224 discloses that a binder is added to a refractory material in a certain ratio, and the composition of the binder is based on coal tar or cutback pitch, expandable caking coal or weak caking. A technology is disclosed in which charcoal is present in a certain ratio.

According to this technique, the viscosity of the mud material is suppressed even during use (high temperature), and the binder remains without separation. As a result, it is described that the mud material is densified and the corrosion resistance is improved.

[0008]

However, the above-mentioned phenolic resin-based mud material has a drawback that it is hardened in the mud gun by heat radiated from the furnace. In addition, in the tap hole during filling, troubles such as seizure between the mud and the tap hole lining may occur.

In the technique described in Japanese Patent Publication No. 2592224, the coal tar or cutback pitch used contains many heavy components, and the viscosity itself is high. If you add intumescent or weak caking coal to this,
The viscosity of the binder itself becomes considerably high. Therefore, there is a problem that the viscosity of the obtained mud material becomes too high, and the filling workability is remarkably reduced.

As a method of improving the workability of filling the mud material, it is conceivable to add a large amount of a binder to the refractory aggregate. However, in this case, when the mud material is used at a high temperature, the porosity increases with the volatilization of the binder, and as a result, the corrosion resistance is significantly reduced, so that this method cannot be used.

In addition, components having a relatively low boiling point in the coal tar or cutback pitch volatilize during use of the mud material without contributing to the reaction,
As a result, there is a problem that the porosity of the mud material is increased and the corrosion resistance is reduced.

The present invention has been proposed to solve the above-mentioned problems of the prior art, and is excellent in the early strength and corrosion resistance (high-temperature strength) required properties of the mud material, and furthermore, has the effect of preventing seizure. It is an object of the present invention to provide a taphole mud material which is inexpensive and has good thermal stability without raising.

[0013]

Means for Solving the Problems A first invention is to provide a refractory aggregate such as alumina, wax, chamotte, silicon carbide and the like.
Coke, carbonaceous raw materials such as graphite, kaolin, refractory clay such as bentonite, and a taphole mud material blended with a binder, the binder has a boiling point of 100 to 450 ° C in coal particles and coal tar. It is a mud material for a taphole characterized by being a mixture with a component.

The present invention has been made as a result of earnestly studying the mechanism of developing the strength of a mud material using a tar mixed with coal particles as a binder. In the process, first, the viscosity of the mud material shows a thickening phenomenon that does not decrease even at high temperatures but rather increases, because a part of the components of coal tar or cutback pitch reacts with coal particles. I figured it out. That is, this reaction is a so-called swelling phenomenon that occurs because the components in the coal tar infiltrate into the fine structure of the coal particles.

As a result of the investigation, it was found that only certain components in the coal tar or cutback pitch contributed to this reaction. Furthermore, it has been found that this specific component is a component having a boiling point range of 100 ° C. or more and 450 ° C. among coal tar. Therefore, in the present invention, a target mud material is obtained by using a specific component in the coal tar instead of the coal tar or the cutback pitch.

The mixture of coal particles and a specific component (boiling point: 100 to 450 ° C.) in coal tar is a slurry substance,
Thermally stable in the low temperature range below 0 ° C and 200 ° C
It has the property of being rapidly solidified by heating as described above. Therefore, various prototypes of mud materials containing a binder having different particle size of coal particles, components of coal tar (by boiling point, by distillation product), and a mixing ratio thereof were studied and studied.

In the process of compounding (kneading) with the refractory aggregate, no particular problem occurred with this mud material. The mixing ratio of this binder to the refractory aggregate was not much different from the conventional tar-based mud material or phenol resin-based mud material. In addition, when the obtained mud materials were heated at 200 ° C. or higher, it was confirmed that these mud materials rapidly solidified and were firmly bonded to the refractory aggregate, and the mud material exhibited early strength.

When the above mixture is used as a binder, coal particles are uniformly dispersed in the raw material of the mud during the mixing (kneading) of the raw material and the mixture.
It was confirmed that the mud material had sufficient plasticity in a low temperature region until it was charged into the mud gun and pressed into the tap hole, and had good thermal stability. In addition, it was confirmed that troubles such as hardening in the mud gun and seizure between the mud and the taphole lining did not occur.

The refractory aggregate is alumina, laurite,
Examples thereof include chamotte, silicon carbide, and the like. These materials are merely examples, and may be substituted for these materials. Similarly, the carbonaceous material is coke, graphite, etc., and the refractory clay is kaolin,
Although it is bentonite, it is needless to say that each alternative may be used.

The second invention relates to a method for producing a coal tar having a boiling point of 100
℃ ~ 450 ℃ components naphthalene absorption oil, tar absorption oil,
A taphole mud material according to the first invention, which is at least one of anthracene oil, decrystallized anthracene oil, benzene, toluene, xylene, and phenols.

The naphthalene-absorbed oil, tar-absorbed oil, anthracene oil, decrystallized anthracene oil, benzene, toluene, xylene, and phenols used in the present invention are relatively easily available because of their industrial production. It is also cheap. In addition, it contains abundant components related to swelling, and when mixed with coal particles to form a slurry, has a significantly lower viscosity than coal tar and is easily kneaded.
Furthermore, the mud material finally obtained is excellent in early strength and corrosion resistance.

According to a third aspect of the invention, a refractory aggregate such as alumina, wax, chamotte, and silicon carbide, a carbonaceous material such as coke and graphite, a refractory clay such as kaolin and bentonite, and a binder are blended. In the taphole mud material, the binder is a mixture of coal particles and a hydrocarbon containing at least 20% by weight of an aromatic compound having 3 to 4 condensed rings. It is a mud material.

In the course of the study, the raw material to be mixed with the binder does not need to be particularly limited to the coal tar component.
It has been found that the effects of the invention can be obtained even with an aromatic compound having 3 to 4 fused rings. Furthermore, in this case, it was found that the concentration of the aromatic compound may be low, and that 20% by weight is sufficient. According to the present invention, the desired mud material can be obtained in this way, and the range of choice of the raw material can be greatly expanded, and the characteristics of the obtained mud material, for example, the early strength and high temperature characteristics, can be controlled.

According to a fourth aspect, the carbon content of the coal particles is 7%.
It is a taphole mud material according to any one of the first to third inventions, which is 8 to 90% by weight.

In the present invention, the performance is improved by appropriately setting the carbon content of the coal particles. If the lower limit of the carbon content is less than this, the swelling reaction with the coal tar component and the like is reduced, and if the carbon content exceeds the upper limit, the swelling reaction is also reduced.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION As the refractory aggregate constituting the mud material of the present invention, those used for conventional tar or phenol resin mud materials can be used. For example, high alumina raw materials such as fused alumina and sintered alumina; acidic raw materials such as laurite and clay chamotte; silicon carbide, silicon nitride, and silicon nitride iron;

In the present invention, at least one of these refractory aggregates is used. The particle size of the refractory aggregate is not particularly limited, and may be appropriately selected according to the required properties of the mud material. Usually, the particle size of the refractory aggregate is 5 to 1
mm is 10-30%, 1-0.1mm is 10-30%, 0.1mm or less is 20-5
It is desirable to adjust to be 0%.

Coke, graphite and the like may be used as the carbonaceous raw material. As the refractory clay, those usually used for mud materials can be used, and examples thereof include kaolin, serinite, bentonite and the like.

The amounts of the refractory aggregate and the refractory clay are not particularly limited, and may be appropriately selected.
It may be about 95% by weight, and the refractory clay may be about 5-20% by weight.

The coal used as the coal particles is not particularly limited, and for example, peat, lignite, subbituminous coal, bituminous coal, anthracite, etc. can be used. In particular, subbituminous coal and bituminous coal are preferable from the viewpoint of handling and properties. More preferably, the effect is large when the carbon content of the coal particles is 78 to 90% by weight.
The particle size of the coal powder is preferably 5 mm or less, more preferably 100 μm or less, for mixing with heavy oil to form a slurry.

The coal tar used is for metallurgy,
It is possible to use by-products in the process of producing coke by carbonizing coal for city gas. In the present invention, a component having a boiling point of 100 ° C to 450 ° C in the coal tar is used. The method for separating the components in such coal tar is not particularly limited, but generally it can be easily obtained by atmospheric distillation or vacuum distillation.

In particular, among these components in coal tar, naphthalene-absorbed oil, tar-absorbed oil, anthracene oil, decrystallized anthracene oil, benzene, toluene, xylene, phenols and the like are industrially produced and obtained. Is easy. In addition, instead of the components in the coal tar, a hydrocarbon containing at least 20 parts by weight of an aromatic compound having 3 to 4 condensed rings may be used. The components in these coal tars and their substitutes are hereinafter referred to as tar distillation components.

The mud material of the present invention may be prepared by mixing the mud material raw material of refractory aggregate, carbonaceous raw material, and refractory clay with coal particles in advance and then adding the above-mentioned tar distillation component. It is also possible to add a mixture of coal particles and tar distillation components in advance to the mud material.

The mixing ratio between the coal particles and the tar distillation component is not particularly limited, but is preferably from 1: 1 to 1: 7 by weight.

Further, in addition to refractory aggregates, carbonaceous raw materials, refractory clay, coal particles and tar components, as a third additive, carbonaceous bituminous substances such as coal tar pitch and petroleum pitch, and phenol resin are synthesized. It is also possible to add resins and various solvents for adjusting viscosity.

[0036]

EXAMPLES In order to confirm the effects of the present invention, a taphole mud material in which a mixture of coal particles and the above-described coal tar distillation component was blended with the mud material raw material was experimentally produced and subjected to a performance test.

The composition of the prototype mud material was as follows: as a refractory aggregate, alumina 20% by weight, laurite (grain size 3 mm or less) 3
0% by weight, silicon carbide (particle size 1mm or less) 20% by weight, silicon nitride 10% by weight, carbonaceous material, coke (particle size 0.1mm
Hereinafter, 10% by weight and 10% by weight of kaolin clay as refractory clay.

As coal particles, 70% by weight of a particle having a particle size of 0.74 mm or less and 70% by weight of a particle having a particle size of 0.10 mm or less are used. Coal tar distillation components include naphthalene-absorbing oil (boiling point: 218 to 282). ° C), tar absorption oil (boiling point: 216-349
C) and decrystallized anthracene oil (boiling point: 178-436 ° C) and components having a boiling range of 150-250 ° C in coal tar and 25
Components at 0-450 ° C were used.

As a comparative example, the ratio of particles having a particle size of 0.74 mm or less was
70% by weight of coal particles, coal tar produced as a coke oven, cutback pitch, and components having a boiling point range of 80 to 150 ° C and 300 to 500 ° C in the coal tar were selected. A 100% coal tar was also used as a comparative example.

Table 1 shows the proportions (%) of these mixtures used as binders in Examples and Comparative Examples.
Table 1 also shows the viscosity of the prepared binder at the kneading temperature (50 ° C.).

[0041]

[Table 1]

In this table, Examples 1 to 6 are examples in which, among components having a boiling point of 100 ° C. to 450 ° C. in coal particles and coal tar, a distilled product produced industrially is applied. Example
7 and 8 have a boiling point of 150-250 in coal particles and coal tar
This is an example in which a component at 250 ° C and a component at 250 to 450 ° C are blended as a binder.

Comparative Example 1 is an example in which coal particles and coal tar are blended as a binder. Comparative Example 2 has a boiling point range of 80 to 150 ° C. in coal particles and coal tar.
Comparative Example 3 is an example in which a component having a boiling point range of 300 to 500 ° C. in coal particles and coal tar is blended as a binder. Comparative Example 4 is an example in which coal particles and cutback pitch are blended, and Comparative Example 5 is an example in which coal tar (without mixing of coal particles) is blended as a binder. The cutback pitch is obtained by converting pitch into a solution with creosote oil.

Next, the consistency, compressive strength, and erosion index were measured in a laboratory by the test method described later. The tapping time was measured by filling a tapping hole of an actual blast furnace with a prototype mud material and tapping. The occurrence of seizure was visually checked after tapping.

The consistency is an index for evaluating the hardness of the mud material, and was measured using a penetrometer, a cone and a sample container specified in a consistency tester JIS K2220 (grease). When this value is 30 or more, it can be evaluated that the composition has good hardness.

The compressive strength was measured according to the test method (JIS R2206) for the compressive strength of refractory bricks. The compressive strength after heating a prototype mud at a test temperature of 300 ° C for 10 to 20 min. Is an index for evaluating the early strength in a low temperature region.
If it can secure Pa or more, the early strength is satisfied.

Among the compressive strengths, the compressive strength after heating of 3 to 5 hrs in an atmosphere of a test temperature of 300 ° C. to 1500 ° C. indicates high-temperature strength, and is an index for indirectly evaluating corrosion resistance. If the compressive strength under these conditions can be secured to 20 MPa or more, the corrosion resistance is satisfied and a stable tapping time for a long time can be secured.

[0048] The erosion index is an index for directly evaluating the corrosion resistance.
The erosion depth after immersing 300 g of the mud material at 1550 ° C. for 3 hours was measured, and this was represented by an index. When this value is 60 or less, good corrosion resistance is obtained.

The tapping time (min./tap) is the time from the start of tapping until the tapping ends and the tapping port is closed again.
The goal is to secure tapping time of 0 minutes or more. Table 2
Figure 6 shows the performance test results of the prototype taphole mud material.
In Table 2, the numbers in the column of the compressive strength indicate the heating temperature and the heating time until the test. For example, 300-10-20mi
n. indicates the compressive strength after heating at a test temperature of 300 ° C. for 10 to 20 min.

[0050]

[Table 2]

From Table 2, it can be seen that Examples 1 to 6 in which an industrially produced distilled product was used as the binder,
It has a consistency of 35 to 37 and a compressive strength of 2 to 21.5 MPa in the low-temperature region (300 ° C for 10 to 30 min), ensuring plasticity and early strength. The high temperature strength is 20 to 52
MPa and erosion index of 41 to 55 are obtained, and good corrosion resistance is secured. As a result, the tapping time of 200 minutes or more was obtained in each case.

Boiling point 150 in coal particles and coal tar
Tables 2 and 3 of Examples 7 to 8 in which the components of 250 to 450 ° C and the components of 250 to 450 ° C were blended showed that the consistency was 35, the compressive strength in the low temperature region was 4.9 to 22 MPa, and the plasticity and the early strength were high. Is ensured. The high temperature strength is 21 ~
58 MPa and an erosion index of 39 to 40 were obtained, and good corrosion resistance was secured. As a result, the tapping time of 200 minutes or more was obtained in each case.

On the other hand, in the comparative example, the result was as follows. First, Comparative Example 1 in which coal particles and coal tar were blended as binders required 35% of the binder to be added in order to ensure proper consistency (plasticity). Therefore, at high temperatures, the high-temperature strength does not reach the target value at 300 to 800 ° C due to an increase in porosity due to volatilization of the binder component. As a result, the corrosion resistance index and tapping time did not reach the targets.

The boiling point range between coal particles and coal tar is 80
Comparative Example 2 in which a component at ~ 150 ° C was blended as a binder
Has no problem with the amount of binder added when producing a mud material as a trial, but does not exhibit early strength. This is because the boiling range of the components in the coal tar is too low at 80 to 150 ° C., so that no swelling reaction occurs with the coal particles when heated. Further, the high-temperature strength does not reach the target of 20 MPa, so that the corrosion resistance is poor. As a result, the tapping time of 200 minutes or more has not been obtained.

The boiling point range between coal particles and coal tar is 30.
Comparative Example 3 in which components at 0 to 500 ° C were blended as a binder
Required 38% of the binder added to ensure proper consistency (plasticity). Therefore, at high temperatures, the porosity increased due to the volatilization of the binder component, and the high-temperature strength was reduced, and as a result, the corrosion resistance index and the tapping time did not reach the targets.

In Comparative Example 4 in which coal particles and cutback pitch were blended as a binder, the amount of the binder added was 39 in order to ensure proper consistency (plasticity).
% Needed. Therefore, at high temperatures, the porosity increased due to the volatilization of the binder component, and the high-temperature strength was reduced, and as a result, the corrosion resistance index and the tapping time did not reach the targets.

In Comparative Example 5 in which coal tar was blended as a binder, the amount of binder added for obtaining plasticity was 19
%, But no early strength, which is a disadvantage of the tar-based mud material, is not exhibited at all. In addition, high temperature strength is the target of 20
Since it does not reach MPa, the corrosion resistance is also poor. As a result, 200
Minute tapping time is not obtained.

The same effects as those of naphthalene-absorbed oil were also obtained by using benzene, toluene, xylene and phenols.

[0059]

According to the present invention, by mixing a mixture of coal particles and a specific tar distillation component with a refractory raw material as a binder, the basic properties for achieving continuous tapping operation, that is, early strength and corrosion resistance. (High temperature strength),
Moreover, an inexpensive mud material can be obtained. Further, this mud material can provide a thermally stable taphole mud material without seizure.

Claims (4)

[Claims] 1. A taphole comprising a refractory aggregate such as alumina, wax, chamotte and silicon carbide, a carbonaceous material such as coke and graphite, a refractory clay such as kaolin and bentonite, and a binder. In the mud material, this binder is used for the coal particles and the boiling point in coal tar of 100 ° C to 450 ° C.
A tapping hole mud material which is a mixture with the following components. 2. The component having a boiling point of 100 ° C. to 450 ° C. in the coal tar is one or more of naphthalene-absorbed oil, tar-absorbed oil, anthracene oil, decrystallized anthracene oil, benzene, toluene, xylene, and phenols. The taphole mud material according to claim 1. 3. A taphole comprising a refractory aggregate such as alumina, wax, chamotte, and silicon carbide, a carbonaceous material such as coke and graphite, a refractory clay such as kaolin and bentonite, and a binder. A mud material for tapholes, wherein the binder is a mixture of coal particles and a hydrocarbon containing at least 20% by weight of an aromatic compound having 3 to 4 condensed rings. 4. The taphole mud material according to claim 1, wherein the carbon content of the coal particles is 78 to 90% by weight.