JP3128427B2 - Alumina / Spinel amorphous refractories - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an alumina / spinel amorphous refractory, and more particularly to an alumina / spinel amorphous refractory for a ladle.

[0002]

2. Description of the Related Art Various applications have been filed for alumina / spinel amorphous refractories. For example, Japanese Patent Application Laid-Open No. 55-23204 discloses that magnesium aluminate spinel is 10-85% and alumina is 5-3% by weight.
A castable refractory for use in a vacuum degassing apparatus or the like, which contains 0% and high alumina cement in a ratio of 10 to 25%, is disclosed.

JP-A-64-87577 discloses 50 to 90% by weight of alumina clinker, 5 to 40% by weight of spinel clinker having a particle size of 1 mm or less, and alumina cement 3
A material consisting of ２５25% by weight is disclosed. Further, JP-A-3-205368 discloses alumina-based refractory raw materials 47 to 47.
Spinel refractory raw material 5 with 94% by weight and particle size of 1 mm or less
A material comprising 40% by weight and 1 to 3% by weight of alumina cement is disclosed.

Japanese Patent Application Laid-Open No. Hei 5-238838 discloses an ultrafine MgO.Al ₂ O ₃ spinel powder having a particle size of 5 μm or less.
Alumina-spinel pouring refractory consisting of 5% by weight, alumina cement of 1 to 20% by weight, balance of alumina raw material, 1 to 15% by weight of ultrafine powder of MgO.Al ₂ O ₃ -type spinel having a particle size of 5 μm or less, particles MgO · Al with a diameter of 1mm or less
₂ O ₃ quality spinel clinker 38 wt% or less, alumina cement 1-20% by weight, the balance being an alumina raw material and the refractory pouring the total amount of the spinel ultrafine spinel clinker is 40 wt% or less Is disclosed.

[0005] Spinel used for the above-mentioned irregular shaped refractory is usually 1900 in the process of spinel material production.
Sintered at a temperature of at least ℃. However, these amorphous refractories have a weak connective structure, and do not have a dense structure.Structural spalling caused by slag infiltration in a composition with a small amount of added spinel and slag in a composition with a large amount of added spinel ( It has disadvantages such as increased peeling damage.

[0006] JP-A-5-238819, chemical composition MgO19~25 wt%, with Al ₂ O ₃ 75 to 81 wt%, has a composition contain inevitable impurities derived from raw materials other , The lattice constant of the spinel crystal is 8.0820 °
The following is an ultrafine spinel powder having an average particle size of 5 μm or less, in which the presence of periclase is not recognized;
gO15~25 wt%, with Al ₂ O ₃ 75-85% by weight,
A spinel crystal having a composition containing unavoidable impurities derived from the raw material and having a lattice constant of 8.0820 ° or less;
(2) The lattice constants are a ₀ = 4.758 ° and c ₀ = 12.99
A spinel-corundum ultrafine powder having an average particle size of 5 μm or less in which 1% or more of corundum crystals coexist and no periclase is observed;
a magnesium compound and an aluminum compound which become gO and Al ₂ O ₃ , and / or a compound containing magnesium and aluminum as MgO in an amount of 19 to 25% by weight;
₂ O ₃ is mixed at a ratio of 75 to 81% by weight or less, and baked at a temperature of 1200 to 1500 ° C. for 40 to 120 minutes to produce a spinel, and pulverized by a pulverizer to an average particle diameter of 5 μm or less. A method for producing ultrafine spinel powder; 15 to 25% by weight of a magnesium compound and an aluminum compound and / or a compound containing magnesium and aluminum, which become MgO and Al ₂ O ₃ by heating, as MgO, respectively, and Al ₂ O ₃ Are mixed at a ratio of 75 to 85% by weight, and baked at a temperature of 1200 to 1500 ° C. for 15 to 120 minutes to produce spinel and corundum, and pulverized by a pulverizer to an average particle diameter of 5 μm or less. A method for producing ultrafine spinel-corundum powder is disclosed.

[0007] The publication discloses that the above-mentioned spinel ultrafine powder or spinel-corundum ultrafine powder is blended as a raw material for basic and neutral amorphous refractories, and cracks or collapse due to digestion during drying of the construction. Disclosure of the fact that it is possible to reduce the moisture content of the amorphous refractory and to obtain a dense construction body as an ultrafine powder without causing cracking or peeling due to volume change during heating, and without impairing corrosion resistance and fire resistance. There is also.

[0008]

However, the above-mentioned Japanese Patent Application Laid-Open
The spinel ultrafine powder or spinel corundum ultrafine powder having an average particle size of 5 μm or less described in -238819 is intended to be applied as an ultrafine powder to basic or neutral amorphous refractories. Yes, which is lower than the sintering temperature of 1900 ° C.
By baking at a temperature of 00 to 1500 ° C., the growth of spinel crystals is suppressed and the pulverization is facilitated, and it is not intended for use in an alumina / spinel amorphous refractory.

Accordingly, an object of the present invention is to provide an alumina / spinel amorphous refractory in which erosion and slag infiltration are suppressed by forming a dense structure.

[0010]

That is, the alumina of the present invention is used.
・ Spinel amorphous refractories are alumina raw materials 40 to 93
weight%,Al ₂ O ₃ : MgO weight ratio = 70: 30-9
Having a composition of 5: 5 and a temperature of 1300-1600 ° C.
Calcined inParticle size 1mm~ 5 μmCalcined spinel 5-4
0% by weight and 2-20% by weight of alumina cement
It is characterized by becoming.Further, the alumina / sulfur of the present invention
Pinel amorphous refractories are 33 to 90 weight of alumina raw material.
%, Spinel material 3-60% by weight, and alumina material
And the total amount of spinel raw materials 40 to 93% by weight, Al
₂ O ₃ : MgO weight ratio = 70:30 to 95: 5
Grains having and calcined at a temperature of 1300-1600 ° C
5 to 40% by weight of a calcined spinel having a degree of 1 mm to 5 μm and
It is characterized by containing 2-20% by weight of Lumina cement.
Sign.

Further, the alumina / spinel amorphous refractory of the present invention comprises 33 to 90% by weight of an alumina raw material, 3 to 60% by weight of a spinel raw material, and a total amount of 40 to 93% by weight of an alumina raw material and a spinel raw material. 5 to 40% by weight of calcined spinel having a particle size of 1 mm to 5 μm, 2 to 20 alumina cement
%, And 10 to 40% by weight of pulverized particles having a particle size of 10 to 50 mm selected from the group consisting of fused alumina, ban shale and alumina brick.

[0012]

The present invention has solved the conventional problems by blending a calcined spinel with a conventional alumina-based amorphous refractory or an alumina / spinel-shaped amorphous refractory.

Here, the calcined spinel used in the present invention has a particle size of 1 mm to 5 μm, and is composed of Al ₂ O ₃ : Mg.
O has a composition of weight ratio = 70: 30 to 95: 5, and 1
It is calcined at a temperature of 300 to 1600 ° C. for 30 to 100 minutes. If the particle size of the calcined spinel exceeds 1 mm, it is not preferable because the strength of the construction body is reduced.
On the other hand, if it is less than 5 μm, the spalling resistance is undesirably reduced. Here, the calcined spinel Al
_{When the} weight ratio of 2O ₃ : MgO is more than 70:30, MgO is not preferable because the digestion resistance is inferior, and when the weight ratio is less than 95: 5, the effect as a spinel is small, which is preferable. Absent. Further, if the calcination temperature is less than 1300 ° C., it is not preferable because spinel generation is insufficient, and if it exceeds 1600 ° C., crystal growth of the spinel becomes large and the effect as the calcined spinel is lost, which is not preferable. . Furthermore, the calcination time is 30
If the time is less than minutes, it is not preferable because the generation of spinel is insufficient, and if it exceeds 100 minutes, the crystal growth of the spinel becomes large and the effect as the calcined spinel is lost, which is not preferable.

[0014] The calcined spinel thus obtained is
The average crystal grain size of spinel is 3 μm or less (normal spinel clinker is 10 μm or more), and the mineral composition is spinel or spinel and corundum.

In the amorphous refractory of the present invention, the calcined spinel is added in an amount of 5 to 40% by weight, preferably 10 to 30% by weight. When the amount is less than 5% by weight, the effect of improving corrosion resistance is small, and
If the content exceeds 40% by weight, the fluidity of the material is lowered and the required amount of added water is increased, which is not preferable.

Further, in the irregular refractory of the present invention,
40 to 93% by weight of alumina raw material, preferably 50 to 8%
0% by weight is blended. As the alumina raw material, for example, sintered alumina, fused alumina, ban shale, bauxite and the like can be used. If the added amount of the alumina raw material is less than 40% by weight, the total amount of the calcined spinel and the alumina cement exceeds 60% by weight, which is not preferable because the fluidity is reduced and the required added moisture is increased.
If the content exceeds 93% by weight, the amounts of the calcined spinel and the alumina cement are reduced, which is not preferable.

In the irregular refractory of the present invention,
A part of the alumina raw material can be replaced with a conventional spinel raw material. In this case, a sintered spinel or an electrofused spinel can be used as the spinel material. By substituting a part of the alumina raw material with the spinel raw material, corrosion resistance and slag infiltration resistance can be improved. The amount of the spinel material added is 3 to 60% by weight, preferably 10 to 50% by weight. If the added amount of the spinel material is less than 3% by weight, the effect of adding the spinel material is small, and if it exceeds 60% by weight, the added amount of the alumina material is undesirably small. When the spinel material is added, the amount of the alumina material added is 33 to 90% by weight, and the total amount of the alumina material and the spinel is 40 to 93% by weight, preferably 50 to 8%.
It is within the range of 0% by weight. If the total amount is less than 40% by weight, the total amount of the calcined spinel and the alumina cement exceeds 60% by weight, which is not preferable because it causes a decrease in fluidity and an increase in necessary water content. 93% by weight
Exceeding the amount of the calcined spinel and alumina cement decreases, and the effect of adding the calcined spinel is small,
It is not preferable because a tissue defect may occur.

The amorphous refractory of the present invention contains 2 to 20% by weight, preferably 8 to 20% by weight of alumina cement. Alumina cement that has been conventionally used in a castable manner can be used.

In the alumina / spinel amorphous refractory of the present invention, 10 to 10
Pulverized particles such as 50 mm of fused alumina, shale, shale and alumina brick can be added to the above-mentioned composition in an amount of 10 to 40% by weight.

The alumina-spinel amorphous refractory of the present invention having the above-mentioned composition ratio is 4 to 8% by weight, preferably 5% by weight, based on a predetermined amount of water, for example, the amorphous refractory.
About 8% by weight can be added and used by a conventional operation.

[0021]

EXAMPLES The alumina / spinel amorphous refractory of the present invention will be further described below with reference to examples. Example 1 This example illustrates the effect of the grain size of the calcined spinel on the construction. The calcined spinel used in this example is Al
71.3% by weight of ₂ O ₃ , 27.7% by weight of MgO, Fe ₂ O
_It has a composition of 0.2% by weight, 0.2% by weight of SiO _{2 and} 0.3% by weight of CaO, and is obtained by firing at 1450 ° C. for 60 minutes. And the average crystal grain size of spinel is 1.5μ
m. The calcined spinel, sintered alumina, and high alumina cement having various particle size ranges described in Table 1 were mixed at the mixing ratio shown in Table 1, and then a predetermined amount of water was added and mixed. 65mm × 114mm × 230
It was poured into a metal frame having a size of mm, molded, cured at 20 ° C. for 24 hours, and further dried for 24 hours to obtain a specimen. A spalling test was performed on each of the specimens obtained as described above as follows: Test method = panel spalling method Sample shape = 65 mm × 114 mm × 230 mm Temperature / time = 1500 ° C. heating 30 minutes ← → release Cold 30 minutes Evaluation method = ◎-small crack generation, ○-medium crack generation, Δ-slightly crack generation Some results obtained are also shown in Table 1.

[0022]

[Table 1]

From the above Table 1, it can be seen that as the particle size of the calcined spinel becomes smaller, oversintering is more likely to occur, which causes a reduction in spalling resistance, and it is not preferable to use a calcined spinel having a particle size of less than 5 μm. I understand.

Example 2 Using the raw materials described in Table 2 below, the following Tables 3 and 4
Are prepared, a predetermined amount of water is added to each of the formulations, mixed, and then poured into a metal frame having a size of 50 mm × 200 mm × 65 mm, molded at 20 ° C. for 24 hours, and cured at 105 ° C. The sample was dried by drying for 24 hours.

Tables 3 and 4 also show the linear change rate after heating and the result of the erosion test of each specimen obtained as described above. The linear change rate after heating was 15 in accordance with JIS R2555.
Results after treatment at 00 ° C. for 3 hours, and the erosion test was performed under the following conditions: Apparatus: Rotary drum erosion test apparatus Sample shape: 50 mm × 200 mm × 65 mm Temperature / time: 1650 ° C.-4 hours Slag exchange every hour Slag: converter slag (CaO / SiO ₂ = 3.65)
1.2 kg / cycle The erosion depth index and the infiltration depth index are calculated by comparing the erosion depth dimension and the infiltration depth dimension of Comparative Examples 4 and 5 in Table 4 with 100.
The smaller the value, the better the corrosion resistance and infiltration resistance.

[0026]

[Table 2]

In Table 2, the calcined spinel A has an average crystal grain size of 1.5 μm and is composed of a mineral composition spinel, and the calcined spinel B has an average crystal grain size of 1 μm and is composed of a mineral composition spinel and corundum. The calcined spinel C has an average crystal grain size of 3 μm and is composed of a mineral composition spinel, and the calcined spinel D has an unclear particle interface, but has an average crystal grain size of about 0.3 μm and a mineral composition spinel.

[0028]

[Table 3]

[0029]

[Table 4]

[0030]

According to the present invention, it is possible to provide an alumina / spinel amorphous refractory in which erosion and slag infiltration are suppressed by forming a dense structure.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-64-87577 (JP, A) JP-A-3-205368 (JP, A) JP-A-4-104965 (JP, A) (58) Investigation Field (Int.Cl. ⁷ , DB name) C04B 35/66

Claims (3)

(57) [Claims] 1. An alumina raw material of 40 to 93% by weight, Al ₂
O ₃ : MgO weight ratio = 70: 30 to 95: 5
And 5 to 40% by weight of calcined spinel having a particle size of 1 mm to 5 [ mu] m calcined at a temperature of 1300 to 1600 [deg.] C. and 2 to 20% by weight of alumina cement. Fixed refractories. 2. An alumina raw material of 33 to 90% by weight, a spinel raw material of 3 to 60% by weight, and a total amount of alumina raw material and spinel raw material of 40 to 93% by weight, Al ₂ O ₃ : MgO weight
It has a composition of a quantity ratio = 70: 30 to 95: 5, and 130
Particle size calcined at a temperature of 0 to 1600 ° C. 1 mm to 5 μm
5-40% by weight of calcined spinel and alumina cement 2
Alumina / spinel amorphous refractory, characterized in that it comprises about 20% by weight. 3. A calcined spinel having 33 to 90 % by weight of alumina raw material and 3 to 60% by weight of spinel raw material, a total amount of alumina raw material and spinel raw material of 40 to 93 % by weight, and a particle size of 1 mm to 5 μm 5 to 40% by weight. , alumina cement 2 to 2
0% by weight , and fused alumina, ban shale and alumina
Particle size 10-50mm selected from the group consisting of brick
To become a grinding grains contain outside multiplying 10-40 wt%
Characterized by alumina and spinel amorphous refractories.