JPH07110792B2 - Basic amorphous refractory - Google Patents

Description

TECHNICAL FIELD The present invention relates to a basic amorphous refractory material.

[Prior Art] In conventional basic amorphous refractories, it is known to use basic aluminum lactate as a binder as disclosed in JP-A-60-65761. Further, JP-A-58-99177 discloses that the hydration of MgO can be prevented by using amorphous silica fine powder for the MgO amorphous refractory.

Further, JP-A-60-108373 discloses that addition of a siliceous raw material prevents cracks and cracks caused by heating and cooling.

[Problems to be Solved by the Invention] However, if MgO clinker and basic aluminum lactate are used alone, fluidity as an irregular shaped refractory kneaded clay, insufficient strength development after firing, and lactic acid disappearing at a high temperature of 800 to 100
There was a problem that the strength decreased at 0 ° C.

In addition, since conventional amorphous refractories that use ultra-fine SiO ₂ are often used in combination with alumina cement, there is a limit to the extension of the pot life when used for MgO quality irregular refractory,
In addition, the corrosion resistance was not always satisfactory.
Similarly, when using a siliceous raw material, the addition amount is 10
There is a problem in corrosion resistance because it is as high as ~ 45 wt% and alumina cement is often used as a binder.

[Means for Solving the Problems] The present invention has been made to solve the above problems.
The present invention is a basic amorphous refractory using MgO clinker, refractory containing 10 to 50 wt% of MgO clinker fine particles in which particles of 0.1 mm or less are 70 wt% or more and particles of 0.005 mm or less are 10 wt% or less. 0.1-5% by weight of basic aluminum lactate applied to 100% by weight of the aggregate, and (A) 2-8% by weight of SiO ₂ ultrafine powder with a particle size of 5 μm or less, (B)
₂ to 8 wt% of at least one kind of SiO ₂ -containing mineral such as silica stone, silica sand, wax stone, and clay having a particle size of 1 mm or less, and 4 to 12 wt% of the total amount of (A) and (B) % The basic amorphous refractory contained in each is the gist.

Refractory aggregates other than the MgO clinker used for the basic amorphous refractory of the present invention include MgO, Al ₂ O ₃ and MgO that are commonly used.
-Al ₂ O ₃ , chromium steel, ZrO ₂ , SiC, etc. are used as appropriate.
In addition, most of these aggregates are generally used with a particle size of 0.1 to 5 mm. Further, as the MgO clinker, seawater MgO clinker, sintered clinker of natural magnesite, or electrofused MgO clinker is used.

The refractory aggregate has 70 wt% or more of particles of 0.1 mm or less, and
It is preferable that particles of 0.005 mm or less contain 10 to 50 wt% of MgO clinker fine particles whose content is 10 wt% or less. That is, if the particles of 0.1 mm or less are not contained in an amount of 70 wt% or more, a gap occurs in the particle size distribution of the refractory aggregate, resulting in an increase in porosity and a decrease in strength of the obtained refractory.

In addition, particles of 0.005 mm or less in MgO clinker fine particles are 10 wt.
%, Slaking tends to occur during storage, and MgO particles of 0.1 mm or less in MgO clinker fine particles are 10 wt.
If it is less than%, the curing time of the amorphous refractory becomes long, which is a problem in use. Further, if the MgO clinker fine particles in the refractory aggregate are more than 50 wt%, the shrinkage after heating of the amorphous refractory becomes large, which is not preferable.

As the basic aluminum lactate, any known one can be used, for example, Takiserum M-25 manufactured by Taki Chemical Co., Ltd.
00 is appropriate. As a composition of basic aluminum lactate, one having an Al ₂ O ₃ / lactic acid molar ratio of about 0.2 to 2.0 is suitable.

If the amount of basic aluminum lactate added is less than 0.1% by weight, the amount of added water increases and the porosity of the construction body increases, which is not preferable. Also, the amount added is 5w outside
If it is more than t%, lactic acid disappears during heating and the amount of generated gas increases, which embrittles the construction body. Further, aluminum lactate is also expensive, so for economic reasons, the amount of aluminum lactate added was set to 0.1 to 5% by weight.

Suitable as ultrafine SiO ₂ powder is silica flour, evaporated silica or the like having a particle size of 5 μm or less, and the amount of addition thereof is 2 to 8% by weight. If the SiO ₂ ultrafine powder having a particle size of 5 μm or less is less than 2 wt% on the outside, the MgO clinker causes slaking during drying of the irregular refractory, and cracks occur in the refractory. In addition, silica flower is 8w outside
If it is more than t%, the viscosity of the kneaded clay increases and it becomes impossible to perform pouring.

If the particle size of the ultrafine SiO ₂ powder is not less than 5 μm, there are problems in terms of the fluidity of the kneaded clay and the strength of the construction body. Further above Mg
Only a combination of O fine particles, aluminum lactate, and ultrafine SiO ₂ powder has a drawback that the MgO clinker has a very high melting point and is difficult to sinter, and the strength after firing does not increase. To solve this problem, it is sufficient to add more SiO ₂ ultrafine powder, but this is not feasible because of the problem that the workability decreases as described above.

The basic amorphous refractory of the present invention includes silica stone, silica sand, wax stone,
It was discovered that the addition of SiO ₂ -containing minerals such as clay has an effect on strength development after firing and does not lower workability, and was invented.

The amount of addition of the SiO ₂ -containing mineral is set to ₂ to 8% by weight.
This is because if the amount added is less than 2% by weight, the effect of improving strength is poor, and if the amount added is more than 8% by weight, no further effect is obtained and the corrosion resistance decreases.
The particle size is 1 mm or less so that it can be uniformly dispersed in the matrix portion of the irregular refractory.

It should be noted that the SiO ₂ ultrafine powder and the SiO ₂ -containing minerals are added as a total amount
4wt% or more is required, but the upper limit is 12wt%. This is because if it is too much, the corrosion resistance is reduced.

The basic amorphous refractory material of the present invention has the above-mentioned composition, and it is effective to use a curing accelerator and / or a curing retarder for adjusting the curing time, if necessary. There are, for example, the following preferable modes of use.

That is, as a curing accelerator, at least 1 wt% or less of one kind of carboxylic acid, aluminum sulfate or the like is applied, and as a curing retarder, 5 wt% of an alkaline earth metal carbonate or the like.
It is preferable to mix the following.

[Examples] Table 1 shows Examples and Comparative Examples of the present invention. In Table 1, the total amount of refractory aggregate is 100 wt%, and the value in () is the outer weight w
It is the amount added by t%.

The fine particles of MgO clinker described as 0.1 mm or less in Table 1 are particles having a particle size of 0.1 mm or less at 70 wt% or more and particles having a particle size of 0.005 mm or less at 10 wt% or less.

Examples 1 to 3 in Table 1 are comparative examples, and Example 1 uses alumina cement instead of aluminum lactate.
Cracks occur after drying at ℃, and the pot life is short, which is not practical.

In Example 2, Al ₂ O ₃ ultrafine powder was used instead of SiO ₂ ultrafine powder, but cracks occurred after drying at 400 ° C., and it was not usable. In addition, Example 3 has a composition in which aluminum lactate and SiO ₂ ultrafine powder are added in combination, and is good without cracks after drying at 400 ° C., but in places where the hot bending strength is weak and abrasion resistance is required. Sufficient service cannot be obtained.

Examples 4 to 9 are examples of the basic irregular-shaped refractory material of the present invention, which has a hot bending strength twice or more as compared with the comparative examples of Examples 1 to 3, and thus the corrosion resistance index of the refractory material, that is, the durability is improved. is doing. In addition, in Examples 7 to 9, chromite, Al ₂ O ₃ , and SiC were used as the refractory aggregates in addition to the MgO clinker, and the basic amorphous refractory material of the present invention contained other aggregates. Indicates that it can be used.

Note that the corrosion resistance index is the value when a slag erosion test is performed by a high frequency induction furnace, but the corrosion resistance indexes of Examples 4 to 9 which are the basic amorphous refractories of the present invention are not so different from the corrosion resistance index of Example 3. However, in Example 1 using alumina cement, the corrosion resistance index is very poor.

[Effects of the Invention] As described above, in the basic amorphous refractory of the present invention, a refractory aggregate containing a predetermined amount of MgO clinker having a predetermined particle size, aluminum lactate, SiO ₂ ultrafine powder, silica stone, silica sand, a rock stone, By adding SiO ₂ -containing minerals such as clay together, workability,
It is possible to manufacture a product with excellent crack resistance and high strength. For steel making, it is a pouring material for ladle,
It is very suitable for clothing materials for tundish, lance, heating furnace hearth, etc., as rotary kiln for cement and waste liquid incinerator.

Claims (1)

[Claims] 1. In a basic amorphous refractory using MgO clinker, particles of 0.1 mm or less are 70 wt% or more and 0.005 or less.
100% by weight of refractory aggregate containing 10 to 50% by weight of MgO clinker fine particles whose particles of mm or less are 10% by weight or less, and 0.1 to 5% by weight of basic aluminum lactate outside (A)
₂ to 8 wt% of SiO ₂ ultrafine powder with a particle size of 5 μm or less
(B) S of silica stone, silica sand, wax stone, clay, etc. with a particle size of 1 mm or less
A basic amorphous refractory material containing 2 to 8 wt% of at least one of iO ₂ -containing minerals on the outer side and 4 to 12 wt% of the total amount of (A) and (B) on the outer side.