JPH06298572A - Mud material - Google Patents

Abstract

PURPOSE:To develop a mud material effective for extending the depth of iron spout, uniformizing the structural strength in the iron spout as far as possible at a high level for different temperatures at different depths, improving the abrasion resistance throughout the whole depth range, remarkably improving the durability in combination with the chemical ablation caused by the component constituting the material, reducing the labor for the discharge of iron slag, improving the working environment and prolonging the furnace life. CONSTITUTION:The mud material is produced by compounding a conventional refractory aggregate for mud material with (A) 1-8wt.% of functional phenolic resin fine particles as a sintering material, (B) 1-12wt.% of AN-Si alloy powder or 1-12wt.% of metallic Al powder and metallic Si powder in total and (C) 8-20wt.% of a novolak phenolic resin as a sintering binder.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mud material.

[0002]

2. Description of the Related Art In recent years, technological innovations such as increasing the amount of tapping due to large-scale blast furnaces and high-pressure operation, drastically reducing coke by blowing pulverized coal, and drastically extending operating years have led to changes in mud material usage conditions. It is harsh and the required quality is becoming higher and higher. Recently, the required characteristics of mud materials have been changing, such as the need for quality in consideration of the work environment has become particularly strong.

That is, the conventional mud material has mainly improved stable operation for the purpose of closing the taphole, tapping and slag, but recently, it has been possible to reduce the work amount and improve the working environment. Mud materials are required to solve the protection of furnace wall bricks around the taphole, which is the most important issue and is the main point of life extension of the furnace body.

[0004] Various blast furnaces at present have a taphole equipped with one to four cooling plates in one furnace, and the normal tapping work uses these tapholes alternately. The problem of opening and closing is usually several hours at the same tap.

However, depending on the operating method, only two diagonal tapholes are alternately used continuously for one week or more,
After that, there is also continuous tapping that uses one tapping continuously due to the method of using the tapped hole in the rest, the situation of the gutter, the trouble of the mud gun, etc. Sometimes you have to

Due to the variety of operations, the mud material is required to have the following characteristics: It has the optimum tenacity and plasticity so as to facilitate the filling work into the taphole by the mud gun; The mud material immediately after filling the inner part should have a shorter firing time and emit less smoke at the time of opening. Sintering strength after firing does not fluctuate due to different temperatures of the taphole length and the firing time. , It is desirable to have a constant strength as much as possible, and it is easy to open holes; corrosion resistance against slag and hot metal, little increase in tap hole diameter, stable tapping speed can be maintained, tapping time The number of pigs per day can be reduced and the number of pig irons per day can be reduced; when filling in the furnace, the adhesiveness with the old material at high temperature, the volume stability at the time of rapid heating, and the fast tapping are stable and stable tapping is possible. Forming and maintaining the mouth depth, It can protect; it does not contaminate the work environment.

[0007] For example, mud materials used for blast furnace taps and the like have been studied for various refractory raw materials, grain composition, binders, etc. in order to have the above-mentioned characteristics. For example, chamotte, loach, coke, clay-based silicate-based materials, high-ban-soil alumina in place of low-van-soil-based, electro-fused (or sintered) alumina, silicon carbide, silicon nitride,
Alumina based on coke and clay as main raw materials is becoming mainstream. In addition, as a binder for caking, the present situation is that conversion from a coal-based tar-based binder to a petroleum-based or resin-based binder is attempted for the purpose of improving the working environment.

[0008]

In recent years, large-scale high-pressure blast furnaces have more than several decades of operating experience, and production technology has become extremely sophisticated. It is becoming more common to set a target for such years of operation. The contents of operation and technological innovation are being pursued year by year, and the blast furnace bricks are now under severe usage conditions, and the service life must be extended.

For that purpose, it is preferable not only to combine the latest advanced technology at the time of construction of the furnace but also to improve the operation technology and the performance of the mud material at the time of actual operation to form a stable taphole. Is important for more efficient production and life extension of the furnace body.

One of the most important factors in improving the working environment and prolonging the life of the furnace body is the extension and stability of the taphole depth.
To secure the extension and stability of the taphole, the taphole is installed at an angle of 10 to 18 ° toward the bottom of the furnace, and the fluid resistance due to the long pipe is also taken into consideration. As the slag time is extended, the frequency of tapping slag work is reduced, and the amount of residual pig iron and residual slag is reduced in the tapping slag work, so that the work can be managed at a constantly low level of hot metal in the furnace, which reduces wind pressure fluctuation It is possible to prevent secondary damages due to sudden wind breaks due to equipment failure, etc., and play a major role in terms of operational stability and safety. Moreover, one of the most important factors in the life extension measures of the furnace body is to reduce the damage of the furnace wall brick under the furnace body. The severely damaged part of the furnace wall brick in the lower part of the furnace body is the part that is subject to norachrome damage (local damage) near the hot water storage surface, and of course the damage around the taphole that discharges hot metal and molten slag is most significant. . Therefore, it is no exaggeration to say that damage to the furnace wall brick around the taphole is the most important factor affecting the life of the furnace body. The main measure to reduce the damage load around the taphole is that there is a part where the furnace shell is opened to install the taphole and the cooling plate etc. are buried. Since the molten iron in the furnace flows in a concentrated manner toward the furnace, the flow of the molten iron around the furnace is reduced and suppressed to suppress the diffusion effect at the interface between the furnace refractory and the molten iron and to cool the water outside the furnace. As a result, the melting rate and mechanical damage of the lower bricks of the furnace body can be efficiently reduced by reducing the reaction rate due to the temperature decrease at the interface. Suppressing the flow around the molten iron slag in the furnace near the taphole is to increase the taphole depth and discharge the molten pigtail from the center of the furnace as much as possible.

Therefore, it is not an exaggeration to say that the role of the mud material is to maintain a stable taphole and depth, to improve the tapping work and to protect the goodwill around the lower taphole of the furnace body. .

However, although the current mud materials have been improved and improved, the stable taphole depth and its performance which are sufficiently satisfied with respect to the movement of the contents in the furnace and the violent downflow of the molten pig iron and its performance. However, the present situation is to cope with the problem by filling a large amount of mud material, reducing the inner diameter of the tuyere at the upper taphole, closing the tuyere, and widening the tuyere spacing in terms of equipment.

With these measures, an increase in the filling amount of the mud material causes an increase in smoke generation and a deterioration of the working environment due to insufficient firing, and if the equipment is dealt with, the air flow rate balance in the furnace is impaired. Absent. Therefore, we developed a mud material suitable for blast furnace operation technology, extended the taphole depth, carried out stable tapping work, and enabled long-time tapping.
One of the most important issues is to reduce the number of pigs per day, reduce the amount of pig iron slag work, and improve the environment.

Conventionally, as a measure for improving the working environment, it has been proposed to change the binder for binding mud materials from a coal tar type to a resin type, which aims to reduce smoking, foul odor, early development of strength and reduction of firing time. As a result, improvements have been made in the environment for filling the taphole, such as shortening the working time.

However, in the blast furnace operation, the mud material filled in the taphole has a temperature gradient of 300 to 400 ° C. from the outside of the furnace to the deep inside of the furnace to 1500 ° C. at the front end of the inside of the furnace.
There is the above range, the mud material sintering strength at each depth is not always satisfactory, and technically it was not possible to sufficiently achieve continuous high strength in the low intermediate temperature range, so there are also problems caused by it. There were many.

In addition, resin mud materials, which have recently become the mainstream in terms of working environment, can be improved in low temperature strength around 300 ° C. by using hexamethylenetetramine, resole or the like as a curing accelerator. The strength increases with decreasing temperature and the degree of decrease tends to 1000
At temperatures above ℃, the strength gradually increases due to the start of sintering of the refractory, but there is a part with weaker structural strength in the depth structure, and the linear expansion of the tissue also tends to contract, and Voids and internal microcracks are generated around the grain boundaries, which easily breaks during the opening work and causes troubles during the tapping work.

Further, when a curing accelerator is used to make the thermosetting property remarkable, the adhesion property with the red-heated accumulated mud material in the furnace is impeded, and the tap hole depth becomes difficult to extend.

Conventionally, the higher the durability of mud material is, the higher the corrosion resistance is, the more conventional the refractory composition for mud material is, the more pure high melting point alumina, alumina spinel, silicon carbide, silicon nitride, coke, etc. The content of clay and silicate minerals having a relatively low melting point tends to be minimized from the viewpoint of chemical erosion, and therefore, it cannot be denied that the refractory composition is difficult to sinter, There is a limit to the strength development that can be obtained from the binder for sintering, and it is the current situation that the strength of each depth portion at different temperatures cannot be adjusted arbitrarily.

Therefore, it is an object of the present invention to extend the taphole depth and to level the tissue strength in the taphole as much as possible while increasing the tissue strength in the taphole at different temperatures. In addition, a mud material that has improved wear resistance over the entire depth and has significantly improved durability in addition to chemical erosion due to material constituents, can reduce the work of tapping waste, improve the environment and prolong the life of the furnace body. To develop.

[0020]

The mud material according to the present invention comprises a refractory aggregate for a conventional mud material, 1 to 8% by weight of functional particulate phenolic resin and Al-S as a sintering material.
1 to 12% by weight of i-based alloy powder or 1 to 12% by weight of metal Al powder and metal Si powder in total, and 8 to 20% by weight of novolac type phenol resin as a binder for sintering are added and blended. And

[0021]

The mud material of the present invention has a strength of 300 degrees as a method of arbitrarily expressing strength at different depths at different temperatures.
By using a functional fine particle phenolic resin in the range of up to 1000 ° C, a strong and uniform carbon bond can be obtained at 700 ° C.
In the above range, the bond due to the formation of the carbide from the metal, that is, in the range of 700 ° C. or higher in the range of 700 ° C. or higher by applying the Al—Si alloy powder or the metallic Al powder and the metal Si powder, the range of 1300 ° C. or higher in the carbide of the metal aluminum component. It is possible to arbitrarily increase the structure strength of the mud material by generating carbides of metallic silicon components at different temperature ranges of reducing atmosphere in each part within the taphole depth.

That is, the present invention is a conventional mud material composed of fused-grain alumina, sintered alumina, bauxite, shale shale, alumina spinel, lozenge, silicon carbide, silicon nitride, carbon material, clay, etc., whose particle size is adjusted. For refractory aggregates for
1 to 8% by weight of functional fine particle phenol resin as a sintering material, 1 to 12% by weight of Al-Si alloy powder or metal Al powder and metal Si powder, and novolac type phenol resin 8 to 8 as a binder for sintering. It relates to a mud material characterized by using 20% by weight.

Among the sintered materials used for the mud material of the present invention,
The functional fine particle phenol resin effective for strength development in a low temperature range (300 to 1000 ° C) has a weight average molecular weight of more than 10,000 and contains 0.1 to 0.3 methylol groups per benzene ring. Among the polymer resins
The boiling dissolution amount in a methanol solvent is 40% by weight or more.

It should be noted that, for an acetone solvent, 2 at room temperature.
It is preferable that the amount of dissolution after 4 hours is less than 50% by weight from the viewpoint of reducing the volume change in the binding process with the binder for binding and the carbonization process.

Since the functional fine-particle phenol resin has an appropriate methylol group in the molecular structure, it has a slow thermosetting property and is no different from other resins such as novolac type phenol resin used as a binder for binding. Since it has excellent affinity and reactivity, and the residual carbon content is very high at 70% by weight or more, it exhibits a homogeneous crosslinked structure in the mud material structure. With high residual coal,
Further, since a homogeneous and strong C—C bond can be formed, the strength of the conventional general novolac type phenol resin powder, coal pitch and petroleum pitch is weak especially in the low temperature region around 300 to 1000 ° C. , Is a solution to the weak point. Further, the slow thermosetting property has excellent adhesiveness without hindering the adhesion with the red-heated accumulated mud material in the furnace.

On the other hand, the strength development in the temperature range from about 700 ° C. to the upper part is expressed by adding Al—Si alloy powder or metallic Al powder and metallic Si powder to produce Al ₄ C ₃ or the like from a metallic aluminum component in a reducing atmosphere. As for the carbide, the metal silicon component produces carbides such as SiC at 1300 ° C. or higher, and the SiO ₂ component in the refractory composition is partially reduced by metallic aluminum to produce the SiC component and the like.
The formation of these carbides contributes to the cohesive strength of the refractory structure,
It is possible to adjust the strength to a desired value together with the sintering of the refractory itself.

In comparison with the functional fine particle phenol resin, the conventional general novolac type phenol resin powder has a weight average molecular weight of 300 to 800 and a functionality of 0 to 0.01 methylol groups per benzene ring. It is extremely less than about one-tenth or less of the particulate phenolic resin, so it has poor thermosetting properties, the amount of residual carbon is less than 50% by weight due to the decomposition that occurs in the carbonization process from polymerization, and the C--C bond is also inhomogeneous. Sufficient strength was not obtained. The resol type phenol resin has a methylol group of 1 to 1 per benzene ring.
There are too many three, the heat curing rate is very fast, and dense and coarse portions are formed in the crosslinked structure in the process of heating, exhibiting inhomogeneous CC bonds, and the heat curing rate is too fast. That is, it is not preferable in that the adhesiveness during hot is impaired.

When the boiling dissolution amount in a methanol solvent is less than 40% by weight among the characteristic values of the functional fine particle phenol resin, the heat melting property and the self-curing property of the functional fine particle phenol resin are deteriorated. In addition, the affinity and reactivity with the novolak type phenolic resin added as a binder for the mud material to the mud material are impaired, resulting in insufficient C—C bond, so that sufficient C—C bond strength is obtained. There is an inconvenience to say.

If the amount added is outside the applicable range of 1 to 8% by weight, for example, if it is less than 1% by weight, the effect of developing strength is weak, and if it exceeds 8% by weight, the linear expansion coefficient of the refractory structure is high. There is an inconvenience such that the degree of the negative tendency becomes large and the viscosity becomes too strong, which makes the filling work by the mud gun difficult.

Further, the Al--Si alloy powder, the metal Al powder, or the metal Si powder used for the purpose of developing the sintering strength in the temperature range of 700 ° C. or higher has a coarse particle size of 100 mesh or more, and the refractory structure is It is not preferable because the dispersibility in the microstructure and the reactivity in the above are impaired.

As is clear from the phase diagram of the Al-Si binary alloy, the content ratio of the Al component in the Al-Si alloy powder is the lowest at the eutectic point near 88% by weight, which is about 577 ° C. From above such an intermediate temperature range, the reaction of forming Al-based carbide is activated, and as the Si component increases, the melting point of Si approaches and becomes higher, and when the content of the Si component reaches around 60% by weight. The melting point is about 1130 ° C. Therefore, 700 to 1300 in the temperature zone inside the taphole
It is most suitable for obtaining the sintering strength in the range of ° C.
In order to obtain the sintering strength especially in the temperature range up to 1000 ° C where the sintering reaction of the refractory aggregate for mud material does not sufficiently occur,
The Al component ratio is required to be 40 to 90% by weight. If the Al component ratio is less than 40% by weight, sufficient strength in the range of 700 to 1000 ° C cannot be obtained. On the other hand, referring to the Si component, clay and silicate minerals having a high SiO ₂ content in the mud material refractory gradually start to sinter at around 1000 ° C. A high-alumina refractory aggregate having a high melting point and a reduced SiO ₂ content tends to be generally adopted from the point of view of loss, and it is difficult to sinter the refractory itself. Therefore, 1
In order to develop the sintering strength in the range of 300 ° C or higher, A
It is necessary that the Si component in the 1-Si-based alloy be contained in an amount of 10 to 60% by weight, and in other ranges, 700
The balance between the strength of 1300 ° C and the strength of 1300 ° C or higher is unfavorable. Also, metal Al powder and metal S
Even when i powder is used together, the composition ratio of the Al component and the Si component is in accordance with the above.

The addition amount of the Al--Si alloy powder or the total addition amount of the metal Al powder and the metal Si powder is 1% by weight.
If it is less than the above, the effect of enhancing the sintering strength cannot be expected, and if the addition amount exceeds 12% by weight, the strength of 700 ° C. or higher becomes too high, and even if the present high-performance opener is used. However, it is not preferable because the opening of the taphole becomes difficult and the mud material forming the depth of the taphole is broken by the resistance at the time of opening.

The addition amount of the novolac type phenol resin which is the binder for caking used in the present invention is 8 to 20.
A range of 10% by weight is preferable, and if less than 8% by weight, the workability of filling the taphole with a mud gun becomes poor, and if more than 20% by weight, the structure of the mud material after firing becomes coarse and durability is reduced, which is preferable. Absent.

[0034]

EXAMPLES The present invention will be further described below with reference to Examples and Comparative Examples. Examples Table 1 below shows the characteristics of the binder for carbon bonding, and Table 2 shows the characteristics of the Al-Si alloy.
Table 3 shows the chemical composition and particle size of the raw material used as the refractory aggregate, and Table 4 shows the composition of the examples and comparative examples. In addition, the symbol KBF resin in the table is a functional fine particle phenol resin (Kanebo Corporation-trade name: Bell Pearl),
The N-type F resin is a general commercial novolak type phenol resin.

[0035]

[Table 1]

[0036]

[Table 2]

[0037]

[Table 3]

[0038]

[Table 4]

[0039]

[Table 5]

The test method for each characteristic comparison shown in Table 4 will be described below. The samples to be used for the measurement of each characteristic value are, for each composition, using a heating type lower mixer, using an N-type F resin solution as a binder for binding, keeping the dough temperature at 30 to 40 ° C., and thoroughly kneading. And used as the clay for molding the specimen. Physical property values were created with a shape of 35 × 35 × 140 mm and a molding pressure of 14.7 MPa, and used as a test piece. Corrosion resistance comparison: * 1 is 15 for high frequency induction furnace type erosion test method
50 ° C x 3 hours, 10 kg of pig iron as an erosion agent and 300 g of blast furnace slag x 6 times are the maximum erosion depths expressed as an index, * 2 is the arc type rotary drum erosion test method at 1550 ° C x 3 hours, erosion 2 kg of pig iron as an agent and 800 g of blast furnace slag × 3 times the maximum erosion depth by exchanging 3 times are shown as an index, and the durability was compared. Thermosetting speed: * 5 is 50 at a molding pressure of 14.7 MPa
2 pieces of mud material briquette molded to mmφ x 50 mmh
Iron plate on 300mmφ kW spiral electric heater
(9 mm × 350 mm × 350 mm) was placed, the surface temperature of the iron plate was kept at 500 ° C., a briquette was placed on the iron plate, and the time required for curing to the upper part was obtained and compared as a heat curing rate.

As a result of a practical test of the mud material of the product 3 of the present invention in a large high-pressure blast furnace (volume 4550 m ³ ), Comparative product 1
On the other hand, the average tapping time of 14 days (1 campaign) was 162 minutes, which was 217 minutes, and the depth of tapping was 3400 mm and 3510 mm. Therefore, by arbitrarily expressing and leveling the strength of different temperature zones of the respective parts within the taphole depth, which is the main object of the mud material of the present invention, wear damage, which is one of the corrosion resistance factors, can be improved, and It is possible to demonstrate that the slow curing property of KBF resin led to depth extension without hindering the adhesiveness during hot work, and at the same time, it was possible to develop an epoch-making mud material that can improve the working environment. It was

[0042]

EFFECTS OF THE INVENTION The mud material of the present invention makes it possible to express the strengths of different temperature zones at the respective parts within the taphole depth of the blast furnace to arbitrarily high strengths and level the strengths. Due to this, the recent mud materials have become highly refractory-oriented with high purity and high melting point due to the pursuit of high corrosion resistance, so it is difficult to sinter the refractory structure, and among the corrosion resistance factors of melt damage resistance and wear resistance damage, Although the erosion resistance has been improved, it is most important to improve the wear damage, which is another factor, especially under the use conditions such as tapping, and the present invention solves this point. Is. In addition, the adhesiveness with the burning mud material in the furnace and the moderate slow thermosetting property to prevent the coarsening and collapse phenomenon of the structure due to the rapid gasification of volatile components in the mud material due to rapid heating , It was possible to achieve excellent characteristics by using a specific resin, which enables the depth of taphole to be extended and maintain stable, and it is possible to significantly reduce the work environment, blockage, and preparation work for holes. Improvements have been made, and daily light tapping work and protection of bricks at the bottom of the blast furnace furnace body can extend the blast furnace operating years. Further, the mud material of the present invention can be applied not only for the purpose of blocking the tap hole of the blast furnace, but also for closing the tap hole of the electric furnace and the gate for handling molten metal.

Claims (1)

[Claims] 1. A conventional refractory aggregate for mud material, containing 1 to 8% by weight of functional fine particle phenolic resin and 1 to 12% by weight of Al-Si alloy powder or metal A as a sintering material.
1 to 12% by weight in total of 1 powder and metallic Si powder, and 8 to 20% by weight of novolac type phenol resin as a binder for sintering, and mixed.