JPH11199336A - Castable refractory - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a eastable refractory that can insure sufficient fluidity, the crude particles are prevented from separating from the fine particles, by specifying the formulation of crude particles, medium-size particles and fine particles in a specific proportion. SOLUTION: This castable refractory comprises (A) 24-32 wt.% of crude particles with particle sizes of 12.0-2.5 mm, (B) 8-16 wt.% of medium-size particles with particle sizes of 2.5-1.0 mm, (C) 17-30 wt.% of fine particles with particle sizes of' 1.0-0.075 mm and (D) the rest of most fine particles with particle sizes of <0.075 mm. There is no specific restriction in the refractory raw materials to be used and alumina, magnesia, spinel, chromium ore, mullite, chamotte, buhlstone, agalmatolite, and the like can be used single or in combination. There is no restriction in binders and dispersant to be used as a bonding agent. The binder is, for example, alumina cement, phosphate salt, water glass and the like. The dispersant is, for example, sodium hexa-metaphosphate, sodium alkylbenzene-sulfonate and the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a tundish,
The present invention relates to castable refractories used for ladles, gutter materials, cover materials, and the like.

[0002]

2. Description of the Related Art Castable refractories used in tundishes, ladles, gutter materials, cover materials, etc. are usually, for example, 25 to 40% by weight of coarse particles having a particle size of 12.0 to 2.5 mm. 18-30% by weight of medium grains having a particle size of 2.5-1.0mm, 15-25% by weight of fine grains having a particle size of 1.0-0.075mm, and fine powder having a particle size of less than 0.075mm 20- Those having a particle size configuration such as 35% are used.

As the refractory raw materials, various refractory raw materials such as alumina, magnesia, spinel, mullite, chamotte, and silica stone are used.

In these castable refractories, alumina cement is usually used as a binder. Note that a special binder such as a phosphoric acid type or a water glass type may be used as the binder.

Various dispersants such as sodium hexametaphosphate, sodium pyrophosphate, and sodium alkylbenzenesulfonate have been used.

The above-mentioned castable refractories are usually constructed by adding a predetermined amount of water, kneading them with a mixer, and then pouring or vibration casting.

[0007]

However, in the conventional castable refractories having the above-mentioned particle size composition, when kneading with a mixer and applying vibration, the degree of separation between coarse particles and fine powder is reduced. There is a problem that the cast body is large and uneven casting is generated in the work body, so that the work body becomes uneven.

As a method of reducing the above problem, a method of reducing the amount of water to be added can be considered. In this case, it is possible to suppress the separation of coarse particles and fine powder, There is a problem that the property cannot be obtained. If the amount of water added is increased in order to ensure fluidity, separation of coarse particles and fine powder cannot be prevented, and there is no point in employing this method.

An object of the present invention is to solve the above problems and to provide a castable refractory capable of ensuring sufficient fluidity while preventing separation of coarse particles and fine powder. I do.

[0010]

In order to solve the above-mentioned problems, the present inventors have proposed a method for forming coarse grains (12.0-2.5 mm), medium grains (2.5-1.0 mm), and fine grains. (1.0-0.075m
m) and fine powder (less than 0.075 mm) are examined in various ways, and by adjusting these compounding ratios, a castable refractory with good fluidity and in which coarse particles and fine powder are difficult to separate can be obtained. , And further conducted experiments and studies to complete the present invention.

That is, the castable refractory of the present invention comprises: coarse particles having a particle size of 12.0 to 2.5 mm: 24 to 32% by weight; medium particles having a particle size of 2.5 to 1.0 mm: 8 to 16 % By weight, fine particles having a particle size of 1.0 to 0.075 mm: 17 to 30% by weight, and the balance is characterized by using fine powder having a particle size of less than 0.075 mm.

That is, in the castable refractory of the present invention, coarse particles, medium particles, and fine particles are set to 24 to 32% by weight, 8 to 16% by weight, and 17 to 30% by weight, respectively, as compared with the conventional particle size constitution. In addition, the weight ratio of the medium grain region is reduced, and by adopting such a particle size configuration, it is possible to obtain a castable refractory having good fluidity and hardly separating coarse particles and fine powder.

As described above, in the castable refractory of the present invention, the proportion of coarse particles is preferably in the range of 24 to 32% by weight. This is because when the proportion of coarse particles exceeds 32% by weight. This is because the degree of separation between coarse particles and fine powder is increased, and when the ratio of coarse particles is less than 24% by weight, characteristics such as spalling resistance are deteriorated.

The ratio of the medium grains is preferably in the range of 8 to 16% by weight.
When the amount of water added exceeds kw%, the separation of fine powder increases when the amount of water added during kneading is increased. Due to the increased separation. In addition, when considering that the added moisture fluctuates, the ratio of medium grains is 10 to 14% by weight.
Is more preferable.

In the castable refractory of the present invention, it is preferable that the ratio of fine particles is in the range of 17 to 30% by weight. It depends greatly. In addition, it is more preferable that the ratio of the fine particles be in the range of 19 to 27% by weight.

There is no particular restriction on the particle size and the mixing ratio of the fine powder of less than 0.075 mm constituting the balance.

There are no particular restrictions on the refractory raw materials to be used, and various raw materials such as alumina, magnesia, spinel, chromite, mullite, chamotte, quartzite and laurite can be used alone or in combination. is there.

Similarly, there is no particular limitation on the binder and dispersant used as the binder. In addition, as a binder, alumina cement, phosphate, water glass, and the like can be used. Also, as a dispersant,
Phosphates such as sodium hexametaphosphate and sodium pyrophosphate and organic dispersants such as sodium alkylbenzene sulfonate and sodium polyacrylate used in ordinary castable refractories can be used alone or in combination. .

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described, and features thereof will be described in more detail. As a refractory raw material,
Using chamotte, mullite, and alumina, they were blended so as to have a particle size configuration as shown in Tables 1 and 2, and castable refractories for comparison (Table 1: sample numbers (comparative examples) 1 to 4) and Castable refractories (Table 2: Sample Nos. (Examples) 5-12) within the scope of the present invention were prepared.

[0020]

[Table 1]

[0021]

[Table 2]

Then, a predetermined amount of water was added to the castable refractory of Comparative Example (Sample Nos. 1 to 4) and the castable refractory of Example (Sample Nos. 5 to 12) and kneaded for 3 minutes with a small universal mixer. . Then, the kneaded sample was poured into the flow cone, and the free flow value when no vibration was applied, the vibration flow value when 1.3 G × 1 min vibration was applied, and the index of the separation state of coarse particles and fine powder were obtained. The diameter of the convex portion at the center of the kneaded sample was measured. The results are shown in Tables 1 and 2.

FIG. 1 is a diagram for explaining the free flow value, the vibration flow value, the diameter of the convex portion at the center of the kneaded sample which is an index of the separation state of coarse particles and fine powder, and the like. The value of the entire diameter A including the 1 expanded portion 1a is
The values shown as the free flow value and the vibration flow value in Tables 1 and 2 (the value of the diameter A when no vibration is applied is the free flow value, and the diameter A when the vibration of 1.3 G × 1 min is applied. Is the vibration flow value), and the diameter B of the convex portion 1b at the center of the kneaded sample 1 in FIG. 1 is the index of the convex portion diameter in Tables 1 and 2 which is an index indicating the separation state of coarse particles and fine powder. Value. Note that the difference between the flow value A and the convex part diameter B indicates the degree of fine powder separation, and the convex part becomes steep, and the greater the difference between A and B, the greater the degree of fine powder separation. .

Sample No. 1 (Comparative Example) in Table 1 is a castable refractory in which the amount of coarse particles is out of the range of the present invention and the amount of medium and fine particles is in the range of the present invention. Yes,
When the added moisture is 7.5% by weight, the free flow value is 10
Although the fluidity is good at 0 mm and the vibration flow value is 190 mm, the coarse particles are convex and the convex diameter is 131 mm, and the degree of separation between coarse particles and fine powder is large. In addition, in the case of the castable refractory of Sample No. 1, when the added moisture was increased to 8.5% by weight, the degree of fine powder separation was further increased.

The sample numbers in Table 1 (Comparative Examples) 2 to 4
Is a castable refractory in which the ratio of the medium-granular portion is out of the range of the claims of the present invention, and the vibration flow value is large to some extent, but the coarse particles are not uniformly spread and remain as convex portions, and fine powder separation occurs. Was observed.

On the other hand, the castable refractories of Sample Nos. 5 to 12 in Table 2 in which the proportions of coarse, medium, and fine grains are within the range of the present invention have large free flow values and vibration flow values, and are excellent. Flow rate (part spread area) and convex part diameter (coarse grain spread area)
Indicate almost the same value, indicating that the degree of separation between coarse particles and fine powder is small.

FIG. 2 schematically shows the flow state when the kneaded samples of sample numbers 5 to 12 are vibrated. In the case of the castable refractory according to the embodiment of the present invention, since the degree of separation between coarse particles and fine powder is small, the diameter (flow value) A of the entire kneaded sample 1 including the spread portion 1a and the diameter B of the convex portion 1b are determined. The difference is small and the convex portion 1b is gentle.

From the above results, it can be seen that the castable refractory of the example of the present invention has better fluidity and less separation of coarse particles and fine powder than the castable refractory of the comparative example.

The castable refractory of the present invention is not limited to the above embodiment, and various applications and modifications can be made within the scope of the invention.

[0030]

The castable refractory of the present invention has a coarse grain,
Medium and fine grains are 24 to 32% by weight, 8 to 16% by weight, and 17 to 30% by weight, respectively. This prevents separation of water and ensures sufficient fluidity.

That is, according to the present invention, when kneading and constructing castable refractories, it is possible to obtain good fluidity without being influenced by the amount of water added during kneading, Separation of coarse particles and fine powder can be prevented, and uneven casting and floating of fine powder can be prevented, and a uniform construction body can be formed.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining a free flow value, a vibration flow value, a diameter of a convex portion at a central portion of a kneaded sample, which is an index of a separated state of coarse particles and fine powder, and the like.

FIG. 2 is a diagram showing a vibration flow value of a kneaded sample according to an embodiment of the present invention, and a diameter of a convex portion at a central portion of the kneaded sample which is an index of a separated state of coarse particles and fine powder.

[Explanation of symbols]

1 kneaded sample 1a expanded portion 1b convex portion A diameter of entire kneaded sample including expanded portion B convex portion diameter

Claims (1)

[Claims] 1. Coarse particles having a particle size of 12.0 to 2.5 mm: 24 to 32% by weight; medium particles having a particle size of 2.5 to 1.0 mm: 8 to 16% by weight; Fine cast of 0 to 0.075 mm: Castable refractory containing 17 to 30% by weight of fine powder having a particle size of less than 0.075 mm in the balance.