JP2000233977A - Press-patching material for filling space within furnace wall of blast furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a press-patching material for filling a space formed on the rear side of lining refractory within the furnace wall of a blast furnace, in such a state that the pass-patching material is excellent in safety and thermal conductivity. SOLUTION: This press-patching material 4 has a composition obtained by adding a liquid novolak type phenolic resin and a powdery phenolic resin as binders to refractory aggregate containing as its main constituent material, at least one material selected from silicon carbide, graphite and petroleum coke, each of which has <=1 mm grain size, wherein if necessary, thermally expansive graphite is further added to the resulting composition in a <=15 wt.% ratio of the graphite to the composition on the inner percentage basis.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a blast furnace wall,
The present invention relates to a press-fitting material to be filled into the back of a refractory lining.

[0002]

2. Description of the Related Art In recent years, the conditions for using refractory linings have become severer due to high-pressure operation, blow-in of heavy oil and pulverized coal, enrichment of oxygen, and the like accompanying the enlargement of blast furnaces. As a countermeasure, wear of the refractory lining is reduced by water spraying on the outer surface of the outer shell or forced cooling by installing a stave cooler.

FIG. 1 schematically shows a vertical sectional structure of a blast furnace wall and a state of press-fitting repair thereof. For the refractory lining (1), carbonaceous bricks are used. A carbonaceous amorphous refractory (3) having a thickness of about 100 mm is filled between the lining refractory (1) and the outer shell (2) by a casting method or a stamping method. Although not shown in the figure,
The furnace wall provided with the stave cooler is filled with a carbonaceous refractory material having a thickness of about 100 mm between the stave cooler and the lining refractory material in the same manner as described above.

[0004] The irregular-shaped refractory (3) acts as a thermal expansion absorption allowance of the lining refractory (1). Further, the carbonaceous material has a good thermal conductivity and thus has a cooling effect.

[0005] The furnace wall of the blast furnace has an irregular refractory (3) due to thermal expansion and contraction of the refractory (1) and contraction and deterioration of the irregular refractory (3) located on the back side thereof due to the high temperature during the operation. A gap (gap) (5) is formed on both side surfaces of ()). That is, in the example of FIG. 1, the gap (5) is generated between the lining refractory (1) and the irregular refractory (3), and between the outer shell (2) and the irregular refractory (3). ). Further, although not shown in the drawing, in the furnace wall provided with the stave cooler, gaps are formed between the lining refractory and the irregular refractory, and between the stave cooler and the irregular refractory.

Although the width of the gap (5) is as small as about several millimeters, the heat conductivity of air is extremely low, so that the cooling effect of the furnace wall is significantly reduced by the heat insulating effect. Therefore, filling the gap (5) with the press-fitting material (4) is performed.
As a conventional press-fitting material, there has been proposed a material prepared by adding a binder of tar or liquid thermosetting resin to graphite-based refractory aggregate to prepare a paste-like material (JP-A-63-297).
487).

As shown in FIG. 1, the press-fitting material (4) is filled by connecting a pressure feed pipe (6) to a perforation provided in the outer shell (2), and passing the gap (5) from the pressure feed pipe (6). ). The filled press-in material (4) is hardened by furnace wall heat and closes the gap (5). By utilizing the fact that the aggregate of the press-fitting material (4) is carbonaceous and has excellent thermal conductivity, the furnace wall cooling effect is prevented from lowering.

[0008]

However, a conventional press-fitting material using tar as a binder is not preferable in terms of working environment because tar contains a large amount of benzopyrene which is a carcinogen. Further, since tar has a property of being in a liquid state at 400 ° C. or lower, it does not sufficiently cure even after filling in the gap, and the thermal conductivity required for the press-fitting material is not sufficient.

On the other hand, press-fitting materials using a liquid thermosetting resin as a binder have been considered. The use of a liquid thermosetting resin as a binder is advantageous in working environment because it hardly contains harmful substances, and has advantages such as easy viscosity adjustment and press-fitting at room temperature.
However, in the case of a mere liquid thermosetting resin, the viscosity decreases in a temperature range from the press-fitting into the gap to the thermosetting, and a uniform structure cannot be obtained by solid-liquid separation between the refractory aggregate and the binder. Therefore, there is a disadvantage that the thermal conductivity of the press-fitting material after curing is not sufficient.

In particular, when the ambient temperature of the gap to be press-fitted is particularly high, when a liquid thermosetting resin is used, in the process of hardening the press-fitting material, the hardening of the surface layer contacting the refractory lining precedes the hardening of the inside. In addition, since the hardening foams with boiling, the press-fitting material structure becomes porous,
This will further promote a decrease in thermal conductivity.

Further, the liquid thermosetting resin shows a tendency to shrink due to evaporation of volatile components even after thermosetting, and due to this shrinking action, a fine gap which causes a decrease in thermal conductivity is formed in the structure of the press-fitting material itself. There is also a problem.

An object of the present invention is to provide a press-fitting material for filling a gap in a blast furnace wall, which solves the above-mentioned conventional disadvantages.

[0013]

SUMMARY OF THE INVENTION The present invention relates to a refractory aggregate mainly composed of at least one selected from the group consisting of silicon carbide, graphite and petroleum coke having a particle size of 1 mm or less, and a liquid as a binder. This is a press-fitting material for filling the blast furnace wall gap produced by adding a novolak type phenol resin and a powdered phenol resin.

In the present invention, a liquid novolak type phenol resin and a powdered phenol resin are used in combination as a binder.
These do not contain carcinogens, unlike tar and the like, and are excellent in safety in working environment. Further, since the liquid novolak type phenol resin is thermoplastic,
Even when the atmosphere temperature in the gap is high at the time of press-fitting the furnace wall into the gap, there is almost no foaming phenomenon which causes the press-fit material to be porous since there is no pre-curing of the surface layer.

In the present invention, the powdered phenolic resin is heated and then softened and melted by filling with a press-fitting material by the combined use with the powdered phenolic resin. Suppress solid-liquid separation during heating of the material structure.

Further, the liquid resin binder has a smaller fixed carbon amount than the solid resin binder, but the powdered phenol resin has a large fixed carbon amount, thereby increasing the residual carbon ratio of the press-fitting material structure and increasing the heat conductivity. Can be increased.

[0017] The press-fitting material of the present invention may further contain 15% by weight or less of expandable graphite. When the expandable graphite is added, the expandable graphite is thermally expanded by receiving heat after filling the press-fitting material, and the thermal expansion improves the adhesion of the press-fitting material to the gap, and the improvement of the thermal conductivity by the press-fitting further increases. Will be noticeable.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The refractory aggregate used in the present invention is selected from the group consisting of silicon carbide, graphite and petroleum coke.
The main material is a seed or more. In addition, silica, alumina, magnesia and the like may be partially combined. However, since these may cause a decrease in thermal conductivity, when these are combined, it is preferably 50% by weight or less of the entire refractory aggregate. Particle size of refractory aggregate is 1
mm or less. Preferably, it is 0.5 mm or less.
Since the gap of the furnace to be filled is narrow, if the particle size exceeds 1 mm, it may not be possible to sufficiently enter every corner of the gap, and the effect of the press-fitting material of the present invention may not be exhibited.

The solid content of the liquid novolak type phenol resin used as a binder in the present invention is a thermoplastic resin. Liquid novolak type phenol resin is about 200 ° C
Thermal curing does not occur at heating temperatures up to 200 ° C., and curing starts in a temperature range exceeding 200 ° C. due to a crosslinking reaction of the resin. That is, after the press-fitting material is filled, the material is hardened by receiving heat from the furnace wall.
The molecular weight of the liquid novolak type phenol resin is not particularly limited, but the average molecular weight is 300 to 1000.
Is preferable because it is easy to adjust the liquid viscosity.

The amount of the solvent for converting the novolak-type phenolic resin into a liquid is preferably small because the evaporation thereof causes the press-in material to contract. For example, the weight ratio of novolak type phenol resin: solvent is preferably in the range of 30:70 to 70:30. The type of solvent for the liquid novolak type phenol resin is not particularly limited, but a polyhydric alcohol having a high boiling point and low volatility and odor is preferred. For example, ethylene glycol (boiling point 198 ° C.), diethylene glycol (24
5 ° C.), triethylene glycol (287 ° C.) and the like.

The powdery phenol resin may be either a novolak type or a resol type. It is preferable to use a high molecular weight type having a softening point of 80 ° C. or higher. If the softening point is lower than 80 ° C., the injection material is melted in the process of mixing with the liquid resin to increase the viscosity of the press-in material, and the press-in filling property tends to be inferior (that is, the viscosity of the press-in material increases, and the gap between the furnace walls increases). Tend to be difficult to enter).

The preferred mixing ratio of the refractory aggregate and the binder is 20 to 60% by weight of the refractory aggregate, and the total amount of the liquid novolak type phenolic resin and the powdered phenolic resin is 40 to 60%.
80% by weight. If the amount of the binder is too large, the press-fitting material shrinks upon curing and the thermal conductivity decreases. On the other hand, if the amount of the binder is too small, the fluidity of the press-fitting material is reduced, and it is insufficient to spread all over the gap.

The mixing ratio of the liquid novolak type phenol resin to the powder phenol resin is 98: 2 to 8 by weight.
A range of 0:20 is preferred. If the ratio of the liquid novolak type phenolic resin is more than 98% by weight, the effect of adding the powdered phenolic resin tends to decrease. If the ratio is less than 80:20, the powdered phenolic resin dissolves in the liquid novolak type phenolic resin, and the viscosity of the resin binder becomes low. It is not sufficient in press-fitting workability due to the increase.

The combination ratio and addition ratio of each of the above binders are adjusted so as to obtain an appropriate viscosity for the press-fitted material within the range of the present invention. Further, before the press-fitting material is pressed into the gap between the furnace walls, it may be heated in advance to obtain an appropriate viscosity.

Expandable graphite is produced by immersing phosphorous graphite in, for example, a mixed solution of concentrated sulfuric acid and concentrated nitric acid, followed by washing with water and drying. On the other hand, expanded graphite is produced by further heating it at about 800 to 1000 ° C. and expanding it by 50 to 300 times in the C-axis direction (direction perpendicular to the carbon layer). In the present invention, graphite in which sulfuric acid is interposed at the layer boundary of graphite, that is, expandable graphite in a state where heat expansion treatment is not performed is used.

The ambient temperature in the gap between the furnace walls filled with the press-in material is usually 100 to 400 ° C. depending on the heat of the furnace wall. When the expandable graphite expands about 1.5 to 3 times at this ambient temperature, the press-fitting material adheres and fills the gap without any gap. The addition ratio of the expandable graphite to the composition of the press-fitting material is 15
% By weight or less. If the content is more than 15% by weight, the expansion becomes excessive, the structure of the press-fitting material becomes porous, and the thermal conductivity decreases. Conversely, in order to obtain the above-mentioned effect of the expandable graphite, the proportion must be at least 1% by weight on an inner basis.

The press-fitting material of the present invention may further contain, for example, metal powder, a hardening accelerator, pitch and the like in addition to the above. Examples of the metal powder that can be added include Al, Si, Mg, and F.
e or an alloy thereof, which has an effect of preventing oxidation of the carbon component. When metal powder is added, a preferable ratio in the press-fitting material is 0.5 to 5% by weight. The hardening accelerator promotes hardening after filling of the press-fitting material. Specific examples include one or more selected from hexamine, active MgO, malic acid, maleic acid, p-toluenesulfonic acid, and the like.

The hardening accelerator promotes hardening of the press-fit material in a low temperature region where the gap between the furnace walls is 200 ° C. or less, and improves the thermal conductivity. However, if added in a large amount, the foaming phenomenon may be caused at a high temperature of 200 ° C. or higher. Therefore, the proportion of the press-fitted material is 5% by weight or less, preferably 0.5 to 3%.
% By weight. The pitch may be a coal-based or petroleum-based pitch having a softening point of 50 ° C. or higher. The pitch has the effect of increasing the strength of the pressed-in material structure by being carbonized by being heated. The ratio is 5% of the total press-fitting material.
% By weight or less is preferable. If the amount is too large, the curing speed of the press-fitting material becomes low.

[0029]

Examples Examples of the present invention and comparative examples are shown below.

[0030]

[Table 1]

[0031]

[Table 2]

Table 1 shows properties and the like of the binder used in each example. Table 2 shows the composition of the press-fitting material of each example and the test results. In each example, the materials were kneaded with the composition shown in Table 2 and then tested by the following methods.

Thermal conductivity; length 200 × width 200 × thickness 30
mm, and after heating at 300 ℃ × 10hrs,
It was measured by the transient hot wire method.

Viscosity: Measured with a B-type viscometer. Heating is
Adjusted in an oil bath. The degree of solid-liquid separation was also evaluated.

Foamability / shrinkage; inner diameter 50 mm × height 10
150 g was cast into a 0 mm container and rapidly heated in an electric furnace to 500 ° C. in 4 hours. After cooling, it was cut in the vertical direction, and the degree of blistering (foaming property) on the upper surface of the construction and the degree of gap (shrinkage) between the construction body and the container were observed.

Each of the press-fitting materials according to the embodiments of the present invention has a high thermal conductivity of the construction and hardly foams or shrinks during curing. In contrast, Comparative Example 1 did not use a powdered phenol resin, had a low viscosity at 120 ° C.,
Solid-liquid separation occurred. In Comparative Example 2 using a resole-type phenol resin that is a thermosetting resin and Comparative Example 3 using a furan resin, solid-liquid separation occurred due to low viscosity at 120 ° C. In addition, the surface of the construction body was foamed due to rapid thermal curing, and furthermore, shrinkage due to solvent evaporation after curing was large.

Comparative Example 4 using a resol type phenol resin and a powdered phenol resin is effective in preventing solid-liquid separation, but cannot improve foaming and shrinkage. In Comparative Example 5, a large amount of expandable graphite was added, and there was no shrinkage but excessive porosity, and the thermal conductivity was reduced.

Examples 3 and 4 and Comparative Examples 1 and 3 were tested by actually inserting them into the blast furnace wall. After kneading the material of each example with a mortar mixer, it was injected with a squeeze-type pump. The press-in amount was about 500 kg for each material.

The effect of each example was confirmed from temperature measurement records by a thermometer buried in the back of the lining of the blast furnace furnace wall. As a result, in the materials of Examples 3 and 4, since the press-fitting material filled the gaps all over, and because there was no foaming or shrinkage, the cooling action by the water spraying of the iron skin was sufficiently propagated to increase the back surface temperature of the lining brick. Dropped. Also, almost no decrease in thermal conductivity over time was observed.

On the other hand, when the materials of Comparative Examples 1 and 3 were used, a decrease in the back surface temperature of the lining brick was observed immediately after press-fitting, but after one week, the temperature rose to about the same level as before press-fitting. Press-fitting was necessary again.

[0041]

The press-fitting material of the present invention uses a mixture of liquid novolak type phenolic resin and powdered phenolic resin as a binder. No problem and safety is high. In addition, due to the synergistic effect of the novolak type phenolic resin being thermoplastic and the addition of the powdered phenolic resin, in the temperature range from press-fitting to thermosetting, it can be used as a conventional material using a thermosetting resin liquid as a binder. Hardly any solid-liquid separation can be seen. In addition, there are almost no problems such as shrinkage due to evaporation of volatile components of the binder after thermosetting, and porosity due to foaming generated when the ambient temperature of the gap to be pressed is high.

As a result, the blast furnace wall using the press-fitting material of the present invention can exert a cooling effect due to the good thermal conductivity of the press-fitting material, and can significantly improve the durability of the lining brick. it can.

In particular, if expandable graphite is further added as in claim 2, the adhesion and filling of the press-fitting material into the gaps becomes more reliable, and the cooling effect can be further improved.

[Brief description of the drawings]

FIG. 1 schematically shows a vertical section of a blast furnace wall and a method of filling a press-fit material.

[Explanation of symbols]

 1: Refractory lining 2: Outer shell 3: Unshaped refractory 4: Press-fitting material 5: Gap 6: Pumping pipe

Continued on the front page (72) Inventor Naotoshi Yasuda 1-3-1 Shinhama, Arai-machi, Takasago-shi, Hyogo F-term in Harima Ceramics Co., Ltd. 4G033 AA14 AA15 AA17 AB24 BA04

Claims (2)

[Claims] 1. A liquid novolak-type phenolic resin and powder as a binder to a refractory aggregate mainly composed of at least one selected from the group consisting of silicon carbide, graphite and petroleum coke having a particle size of 1 mm or less. Press-fitting material for filling the blast furnace wall gap produced by adding phenol resin. 2. A press-fitting material for filling a gap in a blast furnace wall, which is produced by further adding 15% by weight or less of expandable graphite to the press-fitting material according to claim 1.