JPH09183673A - Monolithic refractory - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a monolithic refractory for spraying having properties such as fire resisting characteristic sufficiently durable against repeating use, heat insulating property, extremely low reactivity with materials in a furnace, proper strength, volume stability and spalling resistance due to the heat history and provided with excellent working environmental property and high sticking property. SOLUTION: One or more kinds of refractory raw materials selected from the refractories such as alumina, mullite, chamotte, silica stone, silicon carbide, microsilica, clay are used and these raw materials are composed of 50-70wt.% coarse particle raw material having 0.5-3.5mm particle diameter, 1-7wt.% fine particle raw material having 0.125-0.5mm particle diameter and a fine powder raw material, 95% of which passes through the mesh of 0.125mm, and one or more kinds of additives such as a water holding material, a sizing agent, a water reducing agent or the like and a hardening agent such as alumina cement are blended by 25-45% in total quantity with the fine powder raw material per the refractory raw material having the above particle size constitution.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an amorphous refractory material for spraying.

[0002]

BACKGROUND OF THE INVENTION Blown amorphous refractories are used for forming and repairing refractory linings in industrial kilns.

In the spray refractory disclosed in Japanese Patent Laid-Open No. 62-265181, a small amount of inorganic calcium salt and organic calcium salt are added to the castable refractory in order to improve the adhesion to the wall surface of the furnace, the adhesive strength and the durability. It is configured. It has also been proposed to add an amine silicate together with an inorganic calcium salt and an organic calcium salt to enhance the adhesiveness and the adhesive strength.

Further, in the repairing spray material disclosed in Japanese Patent Laid-Open No. 156080/1988, a small amount of a swelling organic substance, which is an acrylic polymer, is added to a refractory material in order to improve adhesion and hopping resistance. It has become. This repairing spraying material is intended to enhance viscosity and water absorption by the added swelling organic substance and enhance adhesion to the furnace wall surface.

[0005]

The amorphous refractory for spraying for forming and repairing the refractory lining of the industrial kiln is
Generally, the following characteristics must be provided. They are fire resistance, heat insulation, refractory reaction with substances in the furnace, proper strength, volume stability by heat history, spalling resistance, easy dismantling, and easy workability during furnace construction. In particular, with regard to easy workability, it is possible to cite an appropriate construction water width, high adhesiveness, little dust generation, and the like.

However, in the conventional amorphous refractory for spraying, a relatively large amount of a thickener, a water retention agent, a sizing agent, etc. was often added in order to improve the adhesiveness.

For this reason, although the adhesion can be improved, the characteristics of the construction body tend to be deteriorated. That is, the decrease in strength,
Problems such as wear and shrinkage during use, cracking, peeling, and reaction with in-furnace substances due to porosity occur, resulting in shortened service life.

The spray refractories disclosed in the above-mentioned JP-A-62-265181 and JP-A-63-156080 have not yet enjoyed a sufficiently satisfactory service life.

In view of such problems of the prior art, the present invention provides a fire resistance capable of sufficiently withstanding repeated use, a heat insulating property, a difficult reactivity with a substance in a furnace, an appropriate strength, and a volume stability due to heat history. It is an object of the present invention to provide an amorphous refractory for spraying, which has properties such as spalling resistance and good working environment at the time of furnace construction and high adhesion.

[0010]

Means for Solving the Problems The present invention is based on alumina,
Using one or more refractory raw materials selected from mullite, chamotte, silica stone, silicon carbide, micro silica, clay, etc.,
The refractory raw material comprises 50 to 70% by weight of a coarse grain raw material having a grain size of 0.5 to 3.5 mm, 1 to 7% by weight of a fine grain raw material having a grain size of 0.125 to 0.5 mm, and a sieve of 0.125 mm. % Of the fine particle raw material having a particle size that passes through, and one or more additives such as a water retention agent, a sizing agent, a water reducing agent, and a hardening material such as alumina cement are mixed with the fine powder raw material. The gist is an irregular shaped refractory, which is characterized by being mixed in a total amount of 25 to 45% by weight.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The inventors of the present invention suppress the addition of thickeners and sizing agents as much as possible in order to enhance the characteristics of a construction body, and nevertheless provide sufficient adhesive force, so that irregular refractory materials are used. Focusing on the grain size composition of the aggregate. Then, as a result of intensive studies on the particle size constitution of the aggregate, the present invention has been completed.

As the aggregate of the amorphous refractory material of the present invention, one or more refractory raw materials are appropriately selected from refractory materials such as alumina, mullite, chamotte, silica stone, silicon carbide, micro silica and clay. Of course, in addition to these refractory materials, generally used raw materials for amorphous refractory materials can be used as needed.

The refractory raw material has a particle size composition of 0.5 to 0.5.
Coarse-grain raw material of 3.5 mm 50 to 70% by weight, and grain size 0.1
1 to 7% by weight of fine grain raw material of 25 to 0.5 mm, and 0.12
It consists of a fine powder raw material with a particle size that passes through 95% or more of a 5 mm sieve. In the present specification, particles having a particle size of 0.5 to 3.5 mm are coarse particles, particles having a particle size of 0.125 to 0.5 mm are fine particles, and a particle size of 95% or more passes through a 0.125 mm sieve. Those having the above will be referred to as fine powder.

With respect to the refractory raw material having such a particle size constitution, one or more additives such as a water retention agent, a sizing agent, a water reducing agent and a hardening material such as alumina cement are contained in a total amount of 25 to 4 in the fine powder raw material.
5% by weight is added.

Alumina, mullite, chamotte, silica stone,
One or more coarse-grained raw materials (0.5-
The reason why the compounding amount of 3.5 mm) is limited to 50 to 70% by weight will be described.

When a refractory raw material that is coarser than the coarse-grained raw material, that is, a raw material having a grain size of more than 3.5 mm is included, reband loss increases and workability and adhesiveness decrease.
From such a viewpoint, the maximum diameter of the coarse grain raw material is 0.5 to 3
It is preferable to limit to the range of mm.

When the content of coarse particles exceeds 70% by weight, the volume stability, strength, etc., among the above characteristics, cannot be maintained at a good level, and reband loss increases rapidly, resulting in workability and adhesion. Sexual deterioration occurs.

On the other hand, if the amount of coarse particles is less than 50% by weight, the amount of fine-grain raw material or fine-powder raw material increases, resulting in an increase in shrinkage and a decrease in thermal shock resistance, strength, volume stability and the like. However, workability and adhesion are also reduced.

From such a point of view, the blending amount of the coarse grain raw material is preferably 55 to 65% by weight. The optimum amount of coarse particles is 57 to 63% by weight.

Next, alumina, mullite, chamotte,
The reason for limiting the compounding amount of one or more fine grain raw materials (0.125 to 0.5 mm) of a refractory such as silica stone and silicon carbide to 1 to 7% by weight will be described. Note that limiting the compounding amount of fine particles to 1 to 7% by weight is one of the important points of the present invention.

When the content of fine particles is less than 1% by weight,
The contraction increases, and the strength and volume stability also decrease.

On the other hand, when the amount of the fine particles is more than 7% by weight, the particles are close to continuous particles, so that the particles collide with each other and the adhesiveness deteriorates.

From such a viewpoint, the compounding amount of fine particles is 2
~ 6% by weight is preferred. Also, the optimum amount of fine particles is
It is 3 to 5% by weight.

Next, the reasons for limiting the mixing ratio of the fine powder and the additive will be described. One or more fine powder raw materials selected from refractory materials such as alumina, mullite, chamotte, silica stone, silicon carbide, microsilica, and clay that pass 95% or more through a 0.125 mm sieve, and a water retention agent, a sizing agent, a water reducing agent, etc. The total amount of one or more additives and a hardening agent such as alumina cement is 25 to 45
It is designed to be blended in a weight percentage.

When the total amount of the fine powder raw material, the additive, and the curing agent is less than 25% by weight, the adhesiveness is deteriorated and problems such as strength occur.

On the other hand, if the total amount of these exceeds 45% by weight, the shrinkage increases and the strength and the volume stability decrease.

From such a viewpoint, the total amount of the fine powder raw material, the additive and the curing agent is preferably 30 to 40% by weight. In addition, in the optimum mode, the total amount of the fine powder raw material, the additive, and the curing agent is 34 to 39% by weight.

The addition amount of alumina cement in the fine powder raw material is preferably 10 to 20% by weight. The reason is that if it is 10% or less, the adhesiveness is lowered or proper strength cannot be obtained, and if it is 20% or more, the fire resistance and the corrosion resistance are lowered.

As the water retention agent, the sizing agent, and the water reducing agent, those usually used can be used if necessary.

As the hardening material, in addition to alumina cement, a hardening accelerator for alumina cement or the like can be used together.

The amorphous refractory material of the present invention has a structure in which the particle size composition of the refractory material is limited as described above, and a high adhesion property is obtained by its action. Therefore, the amount of additives such as a sizing agent can be significantly reduced as compared with the conventional amorphous refractory. The additive is 25 to 4 in the total amount of the fine powder raw material and the curing agent.
Although it is configured to be added by 5% by weight, it is preferable that the total amount of the water retention agent, the sizing agent and the water reducing agent is 1% by weight or less.

[0032]

EXAMPLES Examples 1 to 3 and Comparative Example 4 of the present invention will be described below.
7 will be described.

Bone preparations (coarse particles), fine particles,
A fine powder and a curing material were mixed, a small amount of a water retention agent and a sizing agent were added thereto, predetermined water was added, and the mixture was kneaded with a universal mixer for 1 minute. Then, a refractory sample for physical property evaluation test was manufactured by punching using a 40 × 40 × 160 mm frame.

Further, the kneaded amorphous refractory material was sprayed with a spraying machine (model alibar 400F: trade name) onto the iron frame for spraying test of FIG. The test iron frame 10 has a large number of studs 11. The dimensions of the iron frame are 900 mm for B and 2200 m for C.
m and D were 1200 mm.

The test results are shown in Table 1. Regarding the adhesiveness, the circle mark indicates good and the triangle mark indicates slightly inferior.

As shown in Table 1, in Examples 1 to 3, the residual shrinkage ratio and the compressive strength to such an extent that no problem occurs in actual use were obtained. The adhesion was also good.

On the other hand, in Comparative Example 4, the adhesion was good, but the shrinkage ratio was large, and good properties in terms of volume stability and strength could not be obtained.

In Comparative Examples 5 to 7, the residual shrinkage and the compressive strength were sufficient, but the adhesion was poor. In the examples, the case where chamotte was used as the refractory material was described, but the same result was obtained when alumina, mullite, silica stone, silicon carbide or the like was used.

[0039]

[Table 1]

[0040]

EFFECTS OF THE INVENTION According to the amorphous refractory of the present invention, it is possible to secure a good working environment with less dust generation, high adhesion and sufficient strength, and other various properties. Therefore, it can be sufficiently applied to various industrial furnaces.

[Brief description of the drawings]

FIG. 1 is a front view showing a test iron frame used in a spray test of an irregular shaped refractory material of an example.

2 is a cross-sectional view taken along the line AA of the test iron frame in FIG.

[Explanation of symbols]

 10 Iron frame for test 11 Stud 12 Test zone 13 Wall surface 14 Base

Claims (4)

[Claims] 1. One or more refractory raw materials selected from refractory materials such as alumina, mullite, chamotte, silica stone, silicon carbide, microsilica, and clay, and the refractory raw material has a particle size of 0.5 to 3.5 mm. 50 to 70% by weight of the coarse grain raw material, 1 to 7% by weight of the fine grain raw material having a grain size of 0.125 to 0.5 mm, and a fine powder raw material having a grain size that passes through a sieve of 0.125 mm by 95% or more. One or more additives such as a water retention agent, a sizing agent, a water reducing agent, and a hardening material such as alumina cement are added to the refractory raw material of the composition in a total amount of 25
An amorphous refractory characterized by being mixed up to 45% by weight. 2. The blending ratio of the coarse grain raw material is 55 to 65% by weight.
The irregular refractory material according to claim 1, wherein 3. The amorphous refractory material according to claim 1, wherein the mixing ratio of the fine grain raw material is 2 to 6% by weight. 4. The total amount of the fine powder raw material, the additive, and the curing material is 30.
The amorphous refractory material according to claim 1, characterized in that the content is -40% by weight.