JPH09157047A - Mud material for tap hole - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mud material for a tap hole having an excellent high- early-strength property and corrosion resistance. SOLUTION: This mud material for the tap hole consists of refractory aggregate, such as alumina, agalmatolite, chamotte and silicon carbide, carbonaceous raw materials, such as cake and graphite, and refractory clay, such as kaolin and bentonite, and is formed by compounding a mixture composed of coal particles and heavy gravity oil. This heavy gravity oil is coal tar or its distillate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mud material for tapholes such as blast furnaces and shaft furnaces, and more particularly to a mud material having excellent early strength and corrosion resistance.

[0002]

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

A mud material for tapping (also called a filling material) for realizing this continuous tapping operation can shorten the time for crimping and holding the mud gun, and the tapping opening does not expand even after tapping for a long time. It is essential (basic characteristic) that the tapping speed can be maintained stably.

To satisfy the above condition, after filling the taphole,
Produce strength by rapidly baking and solidifying (200 ° C
In order to satisfy the expression of low temperature strength in the temperature range below, which is called early strength, it is necessary to have high temperature strength and excellent corrosion resistance to hot metal and slag (temperatures above 400 ° C). The high temperature strength in the region is a measure,
The higher the high temperature strength, the higher the corrosion resistance) is required.

On the other hand, mud materials have hitherto been called by mixing refractory aggregates such as alumina, wax stone, chamotte, and silicon carbide with carbonaceous raw materials such as coke and carbon, and refractory clay such as kaolin and bentonite. The thing using the tar-type binder which added tar, pitch, etc. (henceforth a tar-type mud material) has been generally used.

Recently, a mud material using a synthetic resin such as phenol resin as a binder (hereinafter referred to as a phenol resin-based mud material) is disclosed in Japanese Patent Publication No. 56-6396 and Japanese Unexamined Patent Publication No. 4-280878. It is disclosed. Phenolic resin-based mud material has a relatively high fixed carbon ratio of phenolic resin, so it has high firing strength and excellent corrosion resistance, little black smoke and abnormal dust generation, and a good working environment at opening. It has characteristics such as the above, and is being put to practical use in recent years.

The fixed carbon ratio is a value obtained by subtracting the total of percentages of water, volatile matter and ash in industrial analysis from 100, and is a fixed residue other than ash remaining when carbon etc. is carbonized under specified conditions. Equivalent to. This measurement method is JIS
According to M 8813.

[0008]

In the tar-based mud material, a large amount of tar is added as a binder to soften the mud gun due to equipment restrictions such as mud guns and perforators. ) Must be secured.

However, when the tar is heated to 400 ° C. or higher, the light component in the tar starts to volatilize and is thermally decomposed, and the residual component is carbonized and solidified and sintered to develop strength. In other words, if you do not go through such a process,
Since high temperature strength is not expressed, early strength cannot be obtained.

Further, at this time, since the tar component is volatilized, the refractory structure is fragile and the high temperature strength is low, so that the taphole is easily melted and deteriorated in corrosion resistance. As a result, long tapping per tap (over 200 minutes) cannot be secured,
Continuous tap operation cannot be achieved.

On the other hand, the phenolic resin-based mud material achieves early strength because the phenolic resin as a binder cures at a low temperature of 200 to 300 ° C., thereby eliminating the drawbacks of the tar-based mud material. However, the phenol resin has a large volume shrinkage in the curing and carbonization process, and peels from the aggregate in the high temperature region. Therefore, the phenol resin-based mud material has low high-temperature strength, poor corrosion resistance, and continuous tap operation cannot be achieved.

In addition, phenol resin is
The problem is that it is extremely expensive and causes an increase in manufacturing costs, and that the adhesive force with the old mud material is too strong in the taphole during filling with mud material, or seizure occurs with the taphole lining material. There's a problem. Furthermore, since the mud material before filling is hardened in the mud gun by the heat radiated from the tappipe (this is said to have poor thermal stability in the low temperature range),
There is a problem that the workability before the furnace is poor.

The present invention has been proposed in order to solve the above-mentioned problems of the prior art, and has the basic characteristics for achieving continuous tapping operation, namely fast strength and corrosion resistance (high temperature strength). An object of the present invention is to provide a mud material for tapping, which is excellent, inexpensive, does not cause seizure, and has good thermal stability.

[0014]

According to the invention of claim 1, refractory aggregates such as alumina, wax, chamotte and silicon carbide,
A tapping mud material composed of carbonaceous raw materials such as coke and graphite and refractory clay such as kaolin, serinite and bentonite, and a mixture of coal particles and heavy oil, which is characterized in that Is.

As a result of earnest studies, the inventors of the present invention have found that the above-mentioned refractory aggregates, carbonaceous raw materials, mud raw materials such as refractory clay, which are used in conventional tar-based or phenol resin-based mud materials, are It has been found that the above object can be achieved by blending a mixture of particles and heavy oil as a binder.

First, the mixture of coal particles and heavy oil is
It was found that it is a slurry-like substance and is thermally stable in a low temperature region of 200 ° C. or lower, but has a property of rapidly solidifying when heated at 200 ° C. or higher. This is a so-called swelling phenomenon that occurs because heavy oil infiltrates inside the fine structure of coal (particles).

Therefore, the present inventors paid attention to the mixture having the above-mentioned characteristics, and produced various prototypes of mud materials in which the particle size of coal particles, the type of heavy oil, and the binder in which these compounding ratios were changed, When heated at a temperature of 200 ° C or higher,
It was confirmed that these mud materials rapidly solidified and were strongly bonded to the refractory aggregates, and that the mud materials exhibited early strength.

Further, when the above mixture is used as a binder, coal particles are uniformly dispersed in the mud raw material during the mixing (kneading) process of the mud raw material and the mixture,
In addition, since the mixture has a higher fixed carbon ratio than tar, it contributes to the development of strength as compared with the tar-based mud material using tar as a binder. Therefore, the high temperature strength is remarkably increased, and excellent corrosion resistance to hot metal and slag can be obtained.

Further, the mud material according to the present invention is excellent in early strength and corrosion resistance (high temperature strength).
Coal particles and heavy oil are inexpensive, and mud material is charged into a mud gun and has sufficient plasticity in the low temperature range until it is pressed into the tap hole, and has good thermal stability. In addition, it has excellent characteristics such as curing in the mud gun due to radiated heat, which is a drawback of phenol resin mud material, and no trouble such as seizure between mud and tap lining in the tap hole during filling. Also found to have.

A second aspect of the present invention is a mud material for tapping, wherein the heavy oil is coal tar or a distilled product thereof.

In general, the swelling phenomenon caused by the infiltration of heavy oil into the fine structure of coal is particularly remarkable when heavy oil is coal tar or its distilled product.

Therefore, the inventors of the present invention made various types of mud materials using coal particles and a mixture of coal tar or a distilled product thereof as a binder, and investigated and confirmed their characteristics.
As a result, it was confirmed that, compared with the mud material in which a heavy oil such as coal tar was blended with the above coal particles, the mud material was superior in the early strength, and the high temperature strength was increased, and the corrosion resistance was excellent. It was

[0023]

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

In the present invention, at least one kind 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 characteristics of the mud material. For example, a particle size range of 5 to 1 mm is 10 to 30% by weight (hereinafter abbreviated as%). ), 1 to 0.1 mm
Is preferably 10 to 30%, and 0.1 mm or less is preferably 20 to 50%.

Coke, graphite or the like can be used as the carbonaceous raw material. As the refractory clay, the refractory clay used in conventional mud materials can be used, and examples thereof include kaolin, serinite, and bentonite.

The blending amounts of the refractory aggregate and the refractory clay are not particularly limited and may be appropriately selected. For example, the refractory aggregate may be about 80 to 95% and the refractory clay may be about 5 to 20%. .

The coal used as the coal particles is not particularly limited and, for example, peat, lignite, subbituminous coal, bituminous coal, anthracite and the like can be used. It is preferable because it is stable. The particle size of the coal particles is required to be slurried in order to obtain a uniform mixture with the heavy oil. For this purpose, the particle size is preferably 5 mm or less, more preferably 100 μm or less.

As the heavy oil, either coal-based oil or petroleum-based oil can be used. In the coal system, coal tar, coal liquefaction residual oil, etc. can be used. Petroleum-based heavy oil such as atmospheric residue, vacuum residual oil, asphaltene, which is a straight-run type, cracking-type ethylene tar, FCC decant oil, and oil sand-based orinocotal and cold. A lake or the like can be used.

In the present invention, the refractory aggregate, the carbonaceous raw material, the mud raw material for the refractory clay, and the coal particles may be mixed in advance, and then the heavy oil may be added and blended. It is preferable to add a mixture obtained by previously kneading and heavy oil to the mud material raw material because stable characteristics of the mud material can be obtained.

The blending ratio of the coal particles and the heavy oil is not particularly limited, but the weight ratio is preferably 1: 1 or more and 1: 5 or less.

In addition to refractory aggregates, carbonaceous raw materials, refractory clay, coal particles and heavy oil, carbonaceous bituminous substances such as coal tar pitch and petroleum pitch as a third additive,
It is also effective to add synthetic resins such as phenolic resins and various solvents for adjusting the viscosity.

[0032]

EXAMPLES In order to confirm the effect of the present invention, a mud material for tapholes was prepared by mixing a raw material for mud material with a mixture of coal particles and heavy oil, and was subjected to a performance test.

The composition of the prototype mud material was 20% alumina as a refractory aggregate, and pyrophyllite (grain size 3 mm or less).
30%, silicon carbide (particle size 1 mm or less) 20%, silicon iron nitride 10%, carbonaceous raw material, coke (particle size 0.1 m)
m or less) 10%, 10% kaolin clay as refractory clay
And

The particle size of coal particles is 0.74 m.
70% for m or less, 70 for 0.10 mm or less
%, Two types of heavy oil, tar and two types of petroleum heavy oil, crude anthracene oil as a tar distillation product, and two types of phenol resin, novolac type and resol type, as binder raw materials, A mixture having a blending ratio (%) shown in Table 1 was used as a binder.

[0035]

[Table 1]

Table 2 shows the performance test results of the trial mud material for tapping.

[0037]

[Table 2]

The consistency, compressive strength and erosion index were measured in the laboratory by the test methods described later. The tapping time was measured by filling the tapping port of the actual blast furnace with the trial mud material and tapping. The occurrence of seizure was visually confirmed after tapping.

The consistency is an index for evaluating plasticity, and if this value is 30 or more, it can be evaluated as having good plasticity.

Compressive strength 300 ° C.-10 min-60 mi
n is 1 in the test mud material atmosphere at a test temperature of 300 ° C.
It is the compressive strength after heating for 0 min to 60 min and is an index for evaluating the early strength in the low temperature region. If a compressive strength of 2 MPa or more can be ensured under these conditions, early strength is satisfied.

Compressive strength 300 ° C.-5 hrs-Compressive strength 1
500 ° C.-3 hrs is the high temperature strength after heating at each test temperature, and is an index for indirectly evaluating the corrosion resistance. If the compressive strength under this condition can be secured at 20 MPa or more, the corrosion resistance is satisfied and the stable tapping time is secured for a long time, but if it is 50 MPa or more, seizure with the tapping lining material occurs Undesirably occurs.

The erosion resistance index is an index for directly evaluating the corrosion resistance, and if this value is 60 or less, good corrosion resistance is obtained, but if it is 70 or more, the corrosion resistance deteriorates, which is not preferable.

The tapping time (min / tap) was aimed at securing a tapping time of 200 minutes or more in order to achieve continuous tapping operation.

Examples 1 to 3 are cases where tar was blended as a binder as coal particles and heavy oil. From Table 2, the consistency is 35 and the compressive strength in the low temperature region is 3.8 to 16 MPa, and the plasticity and the early strength are secured. A high temperature strength of 20 MPa or more and an erosion resistance index of 45 were obtained, and good corrosion resistance is secured. As a result, a tapping time of 200 minutes or more was obtained, and it was confirmed that this mud material can achieve continuous tapping operation. Further, the high temperature strength was 50 MPa or less, and seizure did not occur.

Example 4 is a case where coal particles and crude anthracene oil (distilled product of tar as heavy oil) are blended with a binder, and Example 5 is a case where coal particles and petroleum heavy oil are blended with a binder. From Table 2, it was confirmed that almost the same characteristics as in Examples 1 to 3 were obtained, and that these mud materials could also achieve continuous tapping operation.

In Comparative Example 1, tar was used as a binder and 2
This is the case where 0% is blended. In this case, the plasticity is not a problem, but the early-stage strength, which is a drawback of the conventional tar-based mud material, is hardly exhibited. Further, since the high temperature strength of 20 MPa or more is not obtained, the corrosion resistance is slightly inferior. As a result, the tapping time of 200 minutes or more has not been obtained.

Comparative Example 2 is a case where 20% of a novolac type phenol resin is blended as a binder. From Table 2, although the plasticity is not a problem, the early strength does not reach the target value and the high temperature strength has a value close to the target, but the corrosion resistance and the tapping time have not reached the target values.

Comparative Example 3 is a case where 10% of novolac type and 10% of resol type phenolic resin are mixed as a binder. In this case, plasticity is no problem,
Early strength has also reached the target value, but high temperature strength is 300 ° C.
Although the target value was reached at -5 hrs, the target value was not reached in the high temperature region of 800 ° C or higher. Therefore, it is considered that the corrosion resistance index and the tapping time could not reach the target values.

The compressive strength was measured according to the method for testing the compressive strength of refractory bricks (JIS R2206). The corrosion resistance index is a value obtained by measuring the erosion depth after immersing the mud material in the high-frequency induction furnace for 10 kg of pig iron and 300 g of blast furnace slag 6 times and immersing the mud material for 3 hours at 1550 ° C., and expressing it as an index. .

[0050]

Since the mud material of the present invention is composed of the above-mentioned raw material and binder, it is excellent in fast strength and corrosion resistance (high temperature strength) which are basic characteristics for achieving continuous tapping operation. Moreover, it is possible to provide a mud material for tapping that is inexpensive, does not cause seizure, and has good thermal stability (plasticity).

Claims (2)

[Claims] 1. A mud material for a taphole comprising a refractory aggregate such as alumina, wax, chamotte, and silicon carbide, a carbonaceous raw material such as coke and graphite, and a refractory clay such as kaolin and bentonite. A mud material for tapholes, characterized by containing a mixture of heavy oils. 2. The mud material for tapping taps according to claim 1, wherein the heavy oil is coal tar or a distilled product thereof.