JPH0948676A - Amorphous refractory for spraying - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtaind prepared unshaped refractory for gunning that develops less dust, has excellent workability and can provide sufficient works.

SOLUTION: This refractory is obtained by mixing 100 pts.wt. of a refractory material with 2-10 pts.wt. of silica sol or alumina sol, or kneading the mixture together with water added in a quantity of ≥10 pts.wt. It is preferable for this refractory to use silica sol which contains 10-50 wt.% SiO₂ or alumina sol which contains 5-30wt.% Al₂O₃.

COPYRIGHT: (C)1997,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spray-shaped amorphous refractory material (fire-resistant spray material), and more specifically, it is used for repairing blast furnace gutters, mixed pig wheels, converters, ladles, tundish, etc. Regarding standard refractories.

[0002]

2. Description of the Related Art A spraying method, in which a refractory material (unshaped refractory material for spraying) is mixed with water by a nozzle of a spraying machine and sprayed, is easy to construct. It has the feature that the number of construction personnel can be reduced.

Amorphous refractory for spraying used in blast furnace gutters, mixer trucks, converters, ladles, tundish and the like is generally one having alumina cement or phosphoric acid as a binder.

[0004] However, the amorphous refractory for spraying using alumina cement or phosphoric acid as a binder has a problem that dust is inevitable during construction and the working environment is deteriorated. In particular, when the scaly graphite, which is hard to be wetted by water, is contained in an amount of 2% or more, the working environment is significantly deteriorated.

Therefore, as a measure against dust generation, a method of spraying water on the spraying amorphous refractory by a pre-dampener to suppress dust generation, and separating the fine particles from the aggregate and the fine powder constituting the spraying amorphous refractory There are methods such as a method of spraying into a slurry and a method of moistening the spraying amorphous refractory by adding water to the spraying amorphous refractory in advance and kneading before spraying.

However, the above has a problem that the effect of suppressing dust generation is small. In addition, there is a problem that dust cannot be prevented when the sprayable amorphous refractory is put into the hopper from the container bag. Further, the above method has a problem that the concentration of the fine powder slurry and the maintenance and management of the slurry supply equipment are required, which complicates the work. Further, the above method has a problem that the work is complicated because it is necessary to add water to the spraying amorphous refractory in advance before the spraying work and knead the mixture.

[0007] Further, in order to prevent dust generation, a method of previously moistening the amorphous refractory for spraying before shipment from the factory can be considered, but cement and phosphoric acid are not preferable because they elute in water.

The above problems are mainly related to workability and working environment. However, the above-mentioned amorphous refractory for spraying using alumina cement or phosphoric acid as a binder has the following problems in terms of quality of the construction body. There is such a problem. (a) When the cement is hardened with alumina cement or phosphoric acid, the construction body tends to be layered, which causes abrasion due to peeling during operation. (b) Also, in the case of bonding by hydration of alumina cement,
The rapid drying has a problem that explosion occurs due to dehydration of the hydrate. (c) Further, when an amorphous refractory for spraying using alumina cement or phosphoric acid as a binder is constructed, a rebound loss is unavoidable, and therefore a target construction product may not be obtained. Note that this rebound loss is considered to occur when the wetness of the powder during construction is insufficient.

The present invention solves the above problems, and an object thereof is to provide an amorphous refractory material for spraying, which produces little dust, is excellent in workability, and can obtain a good construction body. I am trying.

[0010]

In order to achieve the above object, the spraying amorphous refractory of the first invention of the present application is made of a refractory material 1
Silica sol or alumina sol 2 to 100 parts by weight
It is characterized by adding 10 parts by weight and kneading.

The amorphous refractory for spraying according to the second aspect of the present invention is kneaded by adding 2 to 10 parts by weight of silica sol or alumina sol and 10 parts by weight or less of water to 100 parts by weight of the refractory material. It is characterized by that.

Further, the silica sol contains SiO ₂ of 10
It is those containing 50 wt% and is characterized in that the sol is one which contains Al ₂ O ₃ 5 to 30 wt%.

In the spray-shaped amorphous refractory of the present invention, various commonly used materials can be used as the refractory material (powder). However, since the binder or the binder and water are added and kneaded, hydrated CaO, MgO and the like are not preferable.

In the spray-shaped amorphous refractory of the present invention, since silica sol or alumina sol is added and kneaded as a binder to the refractory material, compared with the above-mentioned conventional method (method using a pre-dampener, etc.), It is possible to reliably suppress dust generation during spraying work. In addition, silica sol or alumina sol is added in advance as a binder,
Since it is kneaded, it is possible to avoid dust generation at the time of throwing in the hopper, and it is not necessary to spray or knead water for the purpose of dust prevention before spraying work, which improves workability. You will be able to improve.

In the spray-shaped amorphous refractory material of the present invention, the binder such as silica sol or alumina sol gels and hardens due to the temperature rise during drying of the construction body, so that a bond such as cement or phosphoric acid is formed. Unlike the one using the binder to be formed, the strength of the construction body is increased and the stratification is suppressed. Therefore, it becomes possible to suppress and prevent the occurrence of peeling during operation.

Further, as described above, the strength of the construction body is increased, and since a bond due to hydration does not occur as in the case where alumina cement is used as a binder, the hydrate is obtained even when it is rapidly dried. Explosion due to the dehydration of will not occur and efficient and good construction can be performed.

Further, by mixing the refractory material and the binder silica sol or alumina sol in advance,
It is possible to suppress the rebound loss due to insufficient wetting and reliably form the target construction body.

In the sprayed amorphous refractory material of the present invention, the proportion of the refractory material and the binder (silica sol or alumina sol) is 100 parts by weight of the refractory material and 2 to 10 parts by weight of silica sol or alumina sol. It is preferable. This is because if the proportion of silica sol or alumina sol is less than 2 parts by weight, wetting of the refractory material becomes insufficient, and if it exceeds 10 parts by weight, it becomes a slurry and cannot be sprayed by conventional spraying equipment.

Further, in the sprayed amorphous refractory material of the present invention, as the silica sol, for example, SiO ₂ particle diameter 5
It is possible to use a commercially available material having a SiO ₂ content of 00 nm or less and a SiO ₂ content of 10 to 50% by weight.

Further, in the spray-shaped amorphous refractory material of the present invention, as the alumina sol, for example, a commercially available one having an Al ₂ O ₃ particle diameter of 500 nm or less and an Al ₂ O ₃ content of 5 to 30% by weight is used. can do.

Further, in the sprayed amorphous refractory of the second invention of the present application, water is added at a ratio of 10 parts by weight or less to 100 parts by weight of the refractory material.
This is because if the amount of water added exceeds 10 parts by weight, the whole becomes a slurry and cannot be sprayed with conventional spraying equipment. When silica sol or alumina sol having a high water content is used, the addition of water may not be necessary. In such a case, the spray-shaped amorphous refractory material is the spray-resistant amorphous material of the first invention of the present application. Equivalent to a standard refractory.

In addition, in the amorphous refractory for spraying of the second invention of the present application, the amount of water added is preferably determined in consideration of the material (type and composition ratio) of the refractory material. That is,
For example, when natural band shale is used as an aggregate, it is desirable to add about 10 parts by weight of water because the water absorption is high. However, when fused alumina having a dense structure is used as an aggregate, the water absorption is Since it is low, it is sufficient to add about 5 parts by weight of water.

The ratio of binder to water is preferably adjusted according to the physical properties required for the construction body. That is, when high strength (mechanical strength such as bending strength) is required, reduce the ratio of water to the binder,
When high corrosion resistance is required, it is desirable to increase the ratio of water to the binder.

[0024]

EXAMPLES The features of the present invention will be described below in more detail with reference to the examples. In this example, a case where a refractory material (Al ₂ O ₃ —SiC—C quality) that is generally used as a blast furnace gutter spraying material is used as the refractory material will be described.

The refractory material (alumina, silicon carbide, scaly graphite and clay), the binder (silica sol or alumina sol) and water were blended and kneaded in the proportions shown in Table 1 to prepare an amorphous refractory for spraying. . As a comparative example,
A refractory material (alumina, silicon carbide, scaly graphite and clay) and alumina cement or sodium phosphate and slaked lime were blended and mixed to prepare an amorphous refractory for spraying.

[0026]

[Table 1]

In Table 1, Samples A, B, C and H are comparative examples outside the scope of the present invention, and others (Samples D, E, F, G, I, J and K are within the scope of the present invention. It is an example in.

In this example, a silica sol having a SiO ₂ content of 40% by weight, a pH of 10 and NaOH stabilization was used as the silica sol, and Al ₂ was used as the alumina sol.
O ₃ content of 10 wt%, pH6, Cl ^- was used an alumina sol stabilization.

Then, the following tests were carried out on the sprayed amorphous refractories of the above-mentioned Examples and Comparative Examples.

Spraying test Spraying was carried out under the following spraying conditions, and the rebound loss, the adhesive strength of the sprayed product and the degree of dust generation were evaluated. [Blowing conditions] Lead gun nozzle diameter: 1.5 inches Discharge rate: 40 kg / min Jet pressure: 3.0 kgf / cm ² Construction shape: (φ) Approx. 500 mm × (t) 150 mm In the spraying test, the nozzle water Spraying was performed by adding an appropriate amount of water from the ring. In addition, sample A using alumina cement as a binder was used as a standard sample, and the rebound loss of each sample, the adhesive strength of the sprayed construction product, and the degree of dust generation were observed. Table 2 shows the results.

[0031]

[Table 2]

However, the rebound loss is shown as a ratio (% by weight) to the total spray amount of the particles which are rebound and become a loss. Regarding the adhesive strength, those equivalent to the standard sample are shown as medium, and those significantly larger than the standard sample are shown as large. Further, regarding the degree of dust generation, those equivalent to the standard sample are shown as medium, those significantly less than that are less, and those much more than that are many. However, Sample H could not be sprayed due to excessive water content.

It can be seen from Table 2 that the samples of the examples have less rebound loss, have the same adhesive strength as the samples of the comparative examples, and have less dust generation.

Explosion test A thermocouple is installed on the surface of a spray-applied body (sample) having a substantially elliptical planar shape and a thickness of 150 mm formed by spraying, and a predetermined temperature rises until the surface temperature reaches 600 ° C. The presence or absence of explosion was determined by heating at a temperature rate (3 ° C / min, 5 ° C / min, 10 ° C / min) and raising the temperature. Table 3 shows the results.

[0035]

[Table 3]

In the evaluation, those in which no explosion was observed were indicated by ◯, and those in which explosion occurred were indicated by x. However, since the sample H was incapable of being sprayed due to excessive water content, the explosion test was not performed. From Table 3, it can be seen that the samples of the examples did not have an explosion.

Test for stratification of construction body The presence or absence of stratification was determined by observing the cross section of the sprayed construction body subjected to the explosion test. Sample A (Comparative example)
Is about 2 in a direction substantially parallel to the sample surface of the cross section.
Fine cracks with a width of about 0.2 mm were observed at intervals of 0 mm.
Further, the cracks were observed as if they were continuous in parallel with the sprayed wall surface, and it was confirmed that the construction body had stratification. Regarding sample B (comparative example), fine cracks having a width of about 0.2 mm were observed at intervals of about 5 mm in the direction substantially parallel to the sample surface in the cross section. Further, the cracks were observed as if they were continuous in parallel with the sprayed wall surface, and it was confirmed that the construction body had stratification. For other samples, only cracks with a width of about 0.5 mm (grooves with a width of about 0.5 mm formed in a direction substantially perpendicular to the surface) were observed on the surface of the samples, and cracks were found inside the construction body. No stratification was observed.

Physical property test After adding an appropriate amount of water and kneading, thrust into a mold and 40 mm ×
After being molded into a shape of 40 mm × 160 mm and dried at 110 ° C. for 24 hours, bending strength and porosity were measured. In addition, the dried sample is 1400 ° C in a coke breeze.
After firing for 3 hours, bending strength and porosity were measured. The results are shown in Table 4.

[0039]

[Table 4]

It can be seen from Table 4 that the samples of the examples have substantially the same or better physical properties than the samples of the comparative examples.

Relationship between the ratio of the binder and water and the characteristics of the construction body The total amount of the binder and water was changed to 8 parts by weight with respect to 100 parts by weight of the refractory material (the same refractory material as the sample in Table 1). The sprayed amorphous refractory was molded using a mold and 1
After drying at 10 ° C. for 10 hours, bending strength and porosity were measured, and after the dried sample was baked at 1400 ° C. for 3 hours in a coke breeze, bending strength,
The porosity was measured. Binder to water ratio (binder /
The relationship between (water) and bending strength and melt loss index is shown in FIG. FIG.
As shown in Fig. 3, when the binder ratio increases, the bending strength increases, but the melting loss index also increases, and corrosion resistance tends to decrease.When the binder ratio decreases, the bending strength decreases, but corrosion resistance decreases. It can be seen that there is a tendency for the value to improve (the melt loss index decreases). Therefore, it is understood that the ratio of water to the binder may be reduced when high strength is required, and the ratio of water to the binder may be increased when high corrosion resistance is required.

In the above embodiment, the case where either the silica sol or the alumina sol is used as the binder has been described, but it is also possible to use both in combination.

The amorphous refractory for spraying of the present invention is not limited to the above-mentioned examples in other points as well, and the brands of silica sol and alumina sol, types of refractory aggregate, composition of refractory material, and improvement of physical properties. It is possible to make various applications and modifications within the scope of the gist of the invention with respect to the presence or absence of the addition of a trace amount of additive to be added, a concrete construction method, and the like.

[0044]

As described above, the amorphous refractory for spraying of the present invention has 2 to 10 parts by weight of silica sol or alumina sol (or 2 to 10 parts by weight of silica sol or alumina sol and 100 parts by weight of refractory material). Less than weight part of water)
Since it is added and kneaded, it has less dust generation and is excellent in workability, and also has little rebound loss and is also excellent in explosion resistance. In addition, the sprayed amorphous refractory work product of the present invention does not form a layer after drying and is excellent in peeling resistance.

Therefore, by applying the spray-shaped amorphous refractory material of the present invention to a blast furnace gutter or the like, it becomes possible to easily and surely form a construction body having excellent durability, which is significant.

[Brief description of drawings]

FIG. 1 is a graph showing the relationship between the ratio of binder and water (binder / water), bending strength, and melt loss index.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kyonobu Toriya 2 1576, Higashioki, Aki, Ako-shi, Hyogo Prefecture 2 Kawasaki Furnace Material Co., Ltd. (72) Innovator Nobuaki Muroi, Ako-shi, Hyogo 2 Kawasaki Furnace Co., Ltd. at 1576 Oki (72) Inventor Seijiro Tanaka 2 Kawasaki Furnace Co., Ltd. at 1576 Higashioki, Nakahiro, Ako City, Hyogo Prefecture

Claims (3)

[Claims] 1. An amorphous refractory for spraying, characterized in that 2 to 10 parts by weight of silica sol or alumina sol is added to 100 parts by weight of a refractory material and kneaded. 2. An amorphous refractory for spraying, characterized in that 2 to 10 parts by weight of silica sol or alumina sol and 10 parts by weight or less of water are added to 100 parts by weight of a refractory material and kneaded. 3. The silica sol contains 10 to 50 SiO ₂ .
The amorphous refractory material for spraying according to claim 1 or 2, characterized in that the content thereof is 5% by weight, and the alumina sol contains 5 to 30% by weight of Al ₂ O ₃ .