JP2942090B2 - Shrinkable mortar for high expansion brick construction - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blast furnace,
Converters, molten steel pots, mortars used when building various molten metal containers such as tundishes with bricks, especially suitable for building furnaces with high thermal expansion bricks Mortar.

[0002]

2. Description of the Related Art Blast furnaces, molten iron pots, mixed iron wheels, converters, molten steel pots,
When building furnaces for various molten metals such as tundishes with bricks, furnaces may be built without using cushioning material between the bricks.However, use cushioning materials to take the expansion allowance of the brick. Often. In this case, a mortar is used, or a material that is burned off by heat, such as cardboard, is used.
In a normal furnace construction, the expansion allowance of the brick can be sufficiently achieved by adding a clay or the like to a refractory material and using a normal mortar kneaded with water.

[0003]

Since the mortar has shrinkage properties, it is usually possible to absorb the expansion allowance of the brick. However, when the brick is highly expandable and has no creep property, In some cases, a problem arises only with the contraction ability of ordinary mortar. Also, when the expansion margin is taken with cardboard or the like, if the portion is not sufficiently tightened, a gap will be formed, and the use of cardboard or the like is particularly dangerous in a molten metal container.

Japanese Patent Application Laid-Open No. 55-167185 discloses a method in which a surfactant is added to a mortar base material to form fine bubbles inside the mortar. It has been found that the agent adversely affects the refractory material and reduces its service life.

Therefore, when building a furnace using a high-expansion brick, development of a new shrinkable mortar in which the mortar has a high hot shrinkage rate and in which each joint shrinks uniformly. Is desired.

[0006]

Means for Solving the Problems The present inventors have studied mortars that meet the above-mentioned requirements, and as a result, have successfully developed a mortar to which a compound that becomes a refractory oxide by being decomposed by heating is added. That is, the present invention relates to a high-expansion brick composed of 50 % by weight or more of one or more powders of one or more compounds in which a refractory material is decomposed by heating to form a refractory oxide, and a refractory powder for building . Mortar. Ma
In addition, the present invention is based on the fact that the refractory material
One or more powders of compounds that will be refractory oxides
Highly expansive brick consisting of 50% by weight or more and remnant of refractory powder
Shrinkable mortar for construction.

[0007] In general mortars, clay or the like is added to a refractory powder such as alumina or magnesia, and the mixture is kneaded with water. In the present invention, the refractory powder is decomposed by heating to obtain a refractory oxide. In place of a mixture of a compound to be used and a conventional refractory powder. The method for producing the shrinkable mortar of the present invention may be produced using the same additives and kneading methods as in the prior art, except that the refractory powder of the mortar to be used is changed to that of the present invention. The particle size to be used may be the same as the conventional one.

The refractory powder used in the present invention is a refractory material used for conventional mortar, and is usually magnesia, calcia, dolomite, spinel, alumina, mullite, alumina silica, silica, or the like.

The compound which is decomposed by heating to form a refractory oxide, which is a feature of the present invention, is a compound which decomposes to a refractory oxide at the operating temperature of a molten metal container. Examples include carbonates, sulfates, nitrates, hydroxides, halides, hydrates, and organic acid salts of magnesium, calcium, aluminum, silicon, zirconium, and the like. At the time of use, one or more of these compounds are selected and used in the same particle size range as the refractory powder used simultaneously. The amount used is 50 % by weight or more of the refractory material, and is appropriately mixed with the refractory powder, but without using the refractory powder, it is also possible to use only a compound which is decomposed by heating to a refractory oxide. It is possible. High expandability
The most common basic non-creep brick
When building bricks, it is decomposed by heating to form
Refractory oxides are basic like magnesia and calcia
It is preferably an oxide.

In the present invention, the combination of the refractory powder and the compound which is decomposed by heating to form a refractory oxide is not particularly limited, but the combination of the compound which is decomposed by heating to form a refractory oxide. However, it is more preferable that the refractory powder is substantially the same as the refractory powder used at the same time or has little mutual reactivity. For example, when the refractory powder is magnesia, the compound which is decomposed by heating to become a refractory oxide is magnesium carbonate or magnesium hydroxide, or calcium carbonate or hydroxide. .

[0011]

The compound used in the present invention, which is decomposed by heating to form a refractory oxide, is decomposed into an oxide when decomposed into an oxide in a temperature range of 300 to 1000 ° C., and the anions are dispersed as a gas to form fine particles. The pores remain, but they act to absorb the expansion of the brick. Since the pores formed by the volatilization of the decomposition gas are very fine and uniform at all joints, the expansion of the brick is equally absorbed and the stress due to the expansion of the brick does not concentrate on a specific place. In addition, since there is no large gap as in the case of using cardboard, there is no need to worry about occurrence of a bullion.

When the amount of the compound which is decomposed by heating and becomes a refractory oxide used in the present invention is increased, the number of pores generated as fine pores increases, and the absorption allowance for expansion increases. The expansion allowance can be adjusted with the same joint thickness depending on the type of brick used. The expansion allowance can be adjusted by changing the type of anions to be decomposed.

[0013]

EXAMPLE 3 3 parts by weight of clay were added to 100 parts by weight of a compound which becomes a refractory oxide by heating when refractory powder such as magnesia powder and magnesium carbonate powder shown in Table 1 were heated, and water was added. In addition, knead and put in a 50 mm φ × 50 mm mold,
After drying, the upper and lower surfaces were restrained and the sample was heated to 1400 ° C., and the maximum thermal stress and shrinkage of the sample were measured. All of the comparative examples in Table 2 are mortars conventionally used. To 100 parts by weight of the refractory powder, 3 parts by weight of clay, a small amount of a known additive was added, and 25 parts by weight of water were added. Using the kneaded material, the evaluation was performed in the same manner as in the examples.

[0014]

[Table 1]

[0015]

[Table 2]

As is clear from the results of Tables 1 and 2, the present invention using a compound which is decomposed by heating to form a refractory oxide has a larger shrinkage ratio than a conventional mortar. Thermal stress can be reduced (Example 2 and Comparative Example 1, Example 6 and Comparative Example 2). Further, the shrinkage ratio can be changed by changing the amount of carbonate or the like used (Examples 1 to 4 and Examples 6 and 7), so that a necessary expansion allowance can be obtained.

[0017]

According to the present invention, as a refractory material for mortar,
By using a mixture of a refractory powder and a compound which is decomposed by heating to form a refractory oxide, or a compound powder alone, it is possible to take allowance for a high-expansion brick. Further, by changing the type and amount of the compound which is decomposed by heating to become a refractory oxide, the expansion allowance can be arbitrarily adjusted without changing the thickness of the mortar. Therefore, the mortar of the present invention exhibits an excellent shrinkage effect as a joint mortar when a furnace is built using high thermal expansion bricks.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Satoshi Tsuboi 26-1 Koshinda, Okayama City (56) References JP-A-55-32783 (JP, A) (58) Fields investigated (Int. Cl. ⁶⁾ , DB name) C04B 35/66

Claims (2)

(57) [Claims] 1. 50 % by weight of powder of at least one compound of a compound which is decomposed by heating to form a refractory oxide when a refractory material is heated
High expansion characterized by the above and the refractory powder remaining
Shrinkable mortar for building bricks . 2. The refractory material is decomposed by heating and becomes basic.
One or more powders of compounds that will be refractory oxides
50% by weight or more and the balance of refractory powder
High expandable brick shrinkable mortar for construction.