JPH11183042A - Method of spraying refractory and spray material used therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the adhesion of a spray material compounded with a carbon material, without deteriorating high corrosion resistance which a carbon material-compounded spray material has in a method of spraying the spray material with an accelerator added in a nozzle. SOLUTION: The method comprises adding water content for execution to a spray material prepared by adding org. fibers 0.01-2 wt.% at outer percentage to 100 wt.% of a refractory compd. contg. needle cokes 0.5-15 wt.%, and then adding an accelerator in a nozzle to spray the material on a wall 3. The needle coke is a high graphitized coke having a developed needle structure obtd. by heat treating e.g. coal tar pitch at 1000 deg.C or higher and pref. has a grain size of 0.5 mm. The org. fibers are e.g. of polypropylene, nylon, PVA (polyvinyl alcohol), polyethylene, acrylic resin, polyester, etc. This improves the adhesion and quickly forms an executed body with a high spalling resistance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refractory spraying method capable of spraying a large amount at a time and forming a thick body.

[0002]

2. Description of the Related Art Refractories used in various kinds of molten metal containers or associated equipment are repaired by spraying the refractories as wear progresses. As one of the spraying construction methods, there has been proposed a method in which a quick-setting agent is added to a spraying material to which a working moisture is added in advance in a nozzle and sprayed. For example, Japanese Patent Application Laid-Open No. 54-61005,
For example, see JP-A-1-119773 and JP-A-62-36070.

[0003] In this method, a large amount of spray can be sprayed at a time by adding the working moisture to the spray material in advance. In addition, since the quick-setting agent is added in the nozzle, there is no problem such as curing of the spray material progressing while the spray material is on standby,
Excellent workability.

[0004]

The spraying material used here has improved corrosion resistance, especially against hot metal, when a carbon material such as graphite, carbon black, pitch, coke, etc. is blended into a part of the aggregate. I do. This is due to the fact that the carbon raw material is hardly wet by hot metal and chemically hardly reacts with hot metal. However, a sprayed material containing a carbon material drastically drops, and it is not easy to form a thick construction body such as a lining furnace repair for a blast furnace gutter or a hot metal vessel.

According to the present invention, in a spraying method in which a spray material containing a carbon material is used and a quick-setting agent is added in a nozzle, the adhesion of the spray material containing a carbon material is maintained without impairing the high corrosion resistance. The purpose is to improve.

[0006]

According to the refractory spraying method of the present invention, an organic fiber is externally applied to a refractory composition containing 0.5 to 15% by weight of acicular coke and 100% by weight of an organic fiber.
After adding the construction moisture to the spray material added by weight% in advance,
It is characterized in that a quick-setting agent is added and sprayed in a nozzle.

[0007] In the spray material, the carbon raw material has an effect on corrosion resistance, but causes a decrease in adhesion. In the spraying method in which the quick-setting agent is added in the nozzle, the spraying material is sprayed without being sufficiently mixed with the quick-hardening agent. This manifests a decrease in adhesion due to the blending of the carbon raw material.

According to the present invention, acicular coke is used as a carbon raw material to be blended with a spray material, and an organic fiber is combined with the coke to form an adhering material without impairing the corrosion resistance of the spray material blended with a carbon raw material. Improvement can be achieved.

Although it is known to add organic fibers for the purpose of spraying material adhesion, the remarkable effect of the present invention can be obtained only in combination with needle coke.
This is presumably because the organic fiber is entangled with the needle-like coke at the needle-like portion and the fiber is further strengthened in the traction effect of the construction body structure by the fiber.

[0010] The fiber material includes metal, ceramic, etc. in addition to organic materials.
Obtained in organic fibers. This is because organic fibers are softer than metal fibers or ceramic fibers, and are more likely to be locked by needle coke.

Further, when sodium silicate is used as the quick setting agent, the spalling resistance of the sprayed construction is improved. When the sprayed construction body was subjected to high temperature heating, sodium silicate SiO ₂
The Si generated by the thermal decomposition of the component reacts with the C component of the acicular coke to generate SiC. The high thermal conductivity of the SiC reduces the temperature gradient in the structure of the construction body, thereby reducing the resistance to soot. It is considered that the polling property is improved.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Needle-like coke is a coke having a high degree of graphitization with a needle-like structure, which is obtained by heat-treating coal tar pitch at a high temperature of 1000 ° C. or more. For use in the present invention, the particle size is preferably 0.5 mm.
In addition, those which have been subjected to a hydrophilic treatment by coating with a surfactant or the like may be used, but are not preferred from the economical viewpoint.

Needle-like coke is a refractory blended composition of a sprayed material.
It accounts for 0.5 to 15% by weight of 0% by weight. More preferably, it is 1 to 10% by weight. If the amount is less than 0.5% by weight, the carbon material has no effect of imparting corrosion resistance. If the amount exceeds 15% by weight, the corrosion resistance is reduced due to oxidation of the acicular coke.

The refractory aggregate other than the acicular coke is not particularly limited. For example, sintered alumina, fused alumina, shale, mullite, pyroxene, chamotte, andalusite, quartzite, sintered magnesia, fused magnesia, sintered magnesia-calcia, fused magnesia-calcia, fused aluminum Main material is ₂ O ₃ -MgO spinel, sintered Al ₂ O ₃ -MgO spinel, chromite, bauxite, sillimanite, zircon, etc., if necessary, zirconia, zircon, silicon carbide, clay, calcined alumina, volatile Combine silica and the like.

Further, carbon raw materials such as scale graphite, earth graphite, anthracite, pitch coke, carbon black and electrode scrap may be used in combination with needle coke. However, it is preferable that the total amount of the carbon material does not exceed 15% by weight due to problems such as adhesion.

The particle size of the refractory aggregate as a whole is determined in consideration of adhesion, filling property, nozzle pumping property and the like as in the case of conventional spraying materials.
Adjusting to coarse, medium, and fine particles is sufficient.

The binder is, for example, alumina cement, magnesia cement, aluminum lactate, Portland cement or the like. The proportion in the refractory composition is 1 to 1
2% by weight is preferred. For example, when ultra-fine magnesia powder such as lightly burned magnesia is used as a part of the refractory aggregate, the ultra-fine magnesia powder also serves as a binder, so that it is not particularly necessary to add it as a binder.

The material of the organic fiber is, for example, polypropylene, nylon, PVA (polyvinyl alcohol), polyethylene, acryl, polyester or the like.

Among these organic fibers, PVA fibers are particularly effective. This is considered to be because the surface of the PVA fiber is melted when it is subjected to heating such as furnace residual heat in the presence of construction water, and the action of locking the needle coke by viscousness and softening is greater.

The proportion of the organic fibers is determined by the above-mentioned refractory composition 1
It is 0.01 to 2% by weight on the basis of 00% by weight. If it is less than 0.01% by weight, there is no adhesion effect, and if it exceeds 2% by weight, the corrosion resistance lowers. The dimensions of the organic fibers are not particularly different from those used for conventional amorphous refractories, and are preferably 0.5 to 25 mm.

Although the present invention requires the use of organic fibers as described above, metal fibers or ceramic fibers may be used in combination with such fibers, if necessary. Examples thereof include metal fibers such as stainless steel, iron, and aluminum, and ceramic fibers such as alumina, silica, alumina-silica, and magnesia. However, a large amount of addition causes a reduction in corrosion resistance and causes clogging of the nozzle. Therefore, it is preferably 5% by weight or less as a proportion of the composition of the refractory composition.

In addition, if necessary, a dispersant, a water reducing agent, a metal powder, a foaming agent, a curing retarder, a curing accelerator, coarse refractory particles and the like may be combined. In particular, the addition of a dispersant is preferable from the viewpoint of a water reducing effect.

Specific examples of the dispersant include sodium tripolyphosphate, sodium hexametaphosphate, sodium polyacrylate, sodium polyacrylate, polycarboxylic acid, and sodium ligninsulfonate. The addition amount is preferably 0.01 to 1% by weight based on 100% by weight of the refractory composition.

The spraying material having the above composition is prepared by adding and kneading water for application in advance to form a slurry. The appropriate amount of construction water at that time varies depending on the particle size configuration of the aggregate, the presence or absence of a dispersant, and the like. However, when the entire sprayed material is 100% by weight, the adjustment can be made within the range of 3 to 15% by weight. preferable.

Specific examples of the quick-setting additive added in the spray nozzle include sodium silicate, slaked lime, calcium oxide, magnesium oxide, sodium phosphate, sodium aluminate, potassium aluminate, calcium aluminates and the like. It does not matter whether it is liquid or powdery, but it is preferable to use it as a liquid dispersed or dissolved in water or the like, because of its good dispersibility in the spray material. For example, water glass can be used as the liquid sodium silicate. The addition amount of the quick setting agent in the nozzle is adjusted within the range of 0.1 to 5% by weight based on the type of the quick setting agent with respect to 100% by weight of the spray material containing the working moisture. Is preferred.

Further, for example, in a nozzle together with sodium silicate, an acrylamide quaternary salt as a flocculant;
A cationic polymer such as a polyamine quaternary salt or a methacrylic acid ester may be added in an amount of 0.1 to 1% by weight based on 100% by weight of the refractory composition.

In particular, when sodium silicate is used as the quick setting agent, as described above, the reaction with the acicular coke causes
Due to the formation of C, the spalling resistance of the sprayed material is improved. Although it is known that SiC has an effect of spalling resistance, SiC generated by reaction with acicular coke
Are ultrafine particles, and it is considered that the spalling resistance is remarkably improved by filling the particles in the matrix portion.

FIG. 1 schematically shows a spraying device used in the present invention. The quick-setting agent supply pipe (2) is connected to the nozzle (1), and the spraying material is sprayed on the wall surface (3) after the quick-setting agent is added in the nozzle (1).
(4) is a spray construction body. Although not shown in the drawing, the supply of the quick setting agent is performed together with the compressed air to promote the mixing of the spray material and the quick setting agent. The material pumping system includes a squeeze type, a screw type, a piston type, and the like, and a piston type which can obtain a high pressure during the pumping is preferable. In the figure, the connection point of the quick-setting agent supply pipe (3) is near the tip of the nozzle (2), but is not limited to this, and may be behind the position shown in the figure according to the working environment.

[0029]

EXAMPLES Table 1 shows Examples and Comparative Examples of the present invention and test results thereof. Each example uses a spraying device using a piston type pumping machine, and sprays a spraying material obtained by adding and mixing water for construction in advance to a vertical wall made of high alumina refractory.
It was sprayed at a rate of 80 kg / min. The hardener was added with auxiliary compressed air near the nozzle tip.

[0030]

[Table 1]

The test method is as follows. Adhesion; 500 mm distance from nozzle tip to sprayed surface
In order to form a 180mm thick construction body.
0 kg was sprayed, and the adhesion rate was determined. Corrosion resistance; after spraying by the method described above, the sprayed body was cut out, dried by heating at 110 ° C. for 24 hours, and the erosion size was measured by a rotary erosion test using molten steel as a solvent. Is shown as an index with 100 as the index. The smaller the value, the better the corrosion resistance.

Spalling resistance: The sprayed body cut out in the same manner as above was placed in an electric furnace at 1400 ° C., taken out after heating for 30 minutes, allowed to cool naturally, and this heating-cooling was repeated until cracks were formed. The number of times was determined.

In an actual machine test, a lining of a molten steel vessel lined with an alumina-based irregular-shaped refractory was sprayed and repaired, and the adhesion state and durability were measured. The state of adhesion was evaluated by visual observation and evaluated on a scale of 1 to 5 (large adhesion 5 ← → small 1). For durability, the wear rate was determined. "-" In the actual machine test results
Indicates not tested.

In the method according to the embodiment of the present invention, there was almost no dripping of the sprayed material, a construction body having a thickness of 180 mm was reliably formed, and an excellent effect was obtained in terms of durability. Among the examples of the present invention, those in which sodium silicate is used as the quick setting agent have excellent spalling resistance. Further, those using PVA for the organic fibers have further improved adhesion.

On the other hand, Comparative Example 1 in which needle-like coke was used but no organic short fiber was added, Comparative Example 2 in which organic fiber was added but no needle-like coke was used, and organic short fiber was used. Comparative Examples 3 and 4 in which carbon materials other than acicular coke were added but which were added were all inferior in adhesiveness to Examples of the present invention. Further, Comparative Examples 4 and 5 in which the amount of needle coke or organic fibers is too large are inferior in corrosion resistance. Comparative Example 6 with a small amount of organic fibers is inferior in adhesion.

The above results are also reflected in actual machine tests.
All of the examples of the present invention are excellent in adhesion. The examples using sodium silicate as a quick setting agent are more excellent in durability than the other examples, due to their excellent spalling resistance.

The spraying method according to the present invention is particularly excellent in durability against pig iron since the spraying material contains a carbon material, and is used for repairing or lining linings of blast furnace gutters, mixed iron wheels, mixed iron furnaces, hot metal pots, and the like. In particular, the effect is great.

[0038]

[Effect] The present invention uses a spray material to which construction moisture is added in advance.
In the refractory spraying method in which a quick-setting agent is added and sprayed in the nozzle, it is possible to improve the adhesion of the carbon-containing material without impairing the corrosion resistance to hot metal. Further, when the type of the quick setting agent is specified in this construction method, the spalling resistance of the spray construction body is improved. As a result, a construction body having a large thickness and excellent spalling resistance can be quickly formed, and the spraying efficiency of the refractory can be significantly improved.

[Brief description of the drawings]

FIG. 1 schematically shows an example of a spraying apparatus used in the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Nozzle 2 Quick setting agent supply pipe 3 Wall surface 4 Spray construction

Claims (3)

[Claims] An organic fiber is added to 100% by weight of a refractory composition containing 0.5 to 15% by weight of acicular coke, and organic fibers are externally applied to the composition.
A method for spraying refractories, characterized in that a spray material added to a content of about 2% by weight is added in advance to the working moisture, and then a quick-setting agent is added and sprayed in a nozzle. 2. The method according to claim 1, wherein the quick-setting agent is sodium silicate. 3. A spraying material used in the refractory spraying method according to claim 1.