JP2766624B2 - 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 having excellent durability, and more particularly to an alumina / spinel amorphous refractory for a ladle.

[0002]

2. Description of the Related Art It is known that spinel has the ability to suppress the infiltration of slag by dissolving components such as FeO and MnO in slag. Various applications have been filed for alumina / spinel amorphous refractories, which can provide superior durability as compared with aluminum refractories. For example,
Japanese Patent Application Laid-Open No. 55-23204 discloses that magnesium aluminate / spinel is 10-85% and alumina is 5% by weight.
A castable refractory for use in a vacuum degassing apparatus or the like is disclosed, in which a high alumina cement is blended at a ratio of 10 to 25% and a high alumina cement at a ratio of 10 to 25%. According to this publication, magnesium aluminate spinel has a molar ratio of MgO: Al ₂ O ₃ of 1: 1 and is 60% on the MgO side and 8% on the Al ₂ O ₃ side.
Although there is a description that a material having a range of 0% can be used, there is no particular reference to the particle size of the magnesium aluminate spinel.

Japanese Patent Application Laid-Open No. 60-60985 discloses that at least 60 parts by weight of spinel clinker, 10 to 35 parts by weight of alumina clinker,
An amorphous refractory composition for ladle lining, comprising 10 parts by weight, is disclosed.

JP-A-64-87577 discloses that alumina clinker is 50 to 90% by weight, spinel clinker having a particle size of 1 mm or less is 5 to 40% by weight, alumina cement 3 is used.
A material consisting of ２５25% by weight is disclosed.

Japanese Unexamined Patent Publication (Kokai) No. 2-6373 discloses that (a) a refractory material comprising 70 to 99% of an aggregate mainly composed of an alumina material and 30 to 1% of fine spinel powder; A cast amorphous refractory comprising at least one of amine silicate, alumina sol and basic aluminum lactate as a binder and (c) alumina cement as a curing agent is disclosed. This publication states that the particle diameter of the spinel fine powder is 100 μm or less, and if the particle diameter is too large, the reaction with the slag is not sufficiently performed, and the penetration of the slag cannot be sufficiently suppressed. is there. In addition,
The cast amorphous refractory described in this publication is obtained by mixing a binder in addition to a refractory material and alumina cement as a hardener, and comprises an amorphous refractory comprising a refractory material and alumina cement. Is a different character.

Japanese Patent Application Laid-Open No. 3-205368 discloses 47 to 94% by weight of an alumina-based refractory raw material,
An alumina-spinel amorphous refractory comprising 5 to 40% by weight of a gO.Al ₂ O ₃ spinel refractory raw material and 1 to 3% by weight of alumina cement is disclosed.
In this publication, MgO · Al ₂ O ₃ spinel refractory raw material of MgO, the weight ratio of Al ₂ O ₃ may not necessarily the theoretical composition, MgO: weight ratio of Al ₂ O ₃ is 10/90
It is described that those in the range of from 40/60 to 40/60 are preferable. Further, when the particle size is 1 mm or more, the slag permeability is remarkably deteriorated. It is disclosed that there is almost no effect of suppressing the corrosion resistance, and that when used in an amount exceeding 50% by weight, the corrosion resistance is significantly reduced.

Japanese Patent Application Laid-Open No. 5-238838 discloses an ultrafine MgO.Al ₂ O ₃ spinel powder having a particle size of 5 μm or less.
5 wt%, MgO.Al ₂ O ₃ -based spinel clinker having a particle size of 1 mm or less 38 wt% or less, alumina cement 1-2
0 wt%, the balance being composed of an alumina raw material, and the total amount of the spinel ultrafine powder and the spinel clinker is 40%.
Disclosed is a cast refractory having a wt% or less. According to this publication, the blending of ultrafine spinel powder is extremely effective for slag erosion resistance and slag penetration resistance. The average particle size is preferably 0.1 to 3 μm, and the effect is less than 1 wt%. There is a disclosure that when the content exceeds 15 wt%, the amount of construction moisture increases and a dense construction body cannot be obtained. In addition, it is described that in a spinel clinker having a particle diameter of 1 mm or less, it is preferable that the ratio of each component of MgO and Al ₂ O ₃ constituting the spinel is larger in the Al ₂ O ₃ component than in the theoretical composition.

Japanese Unexamined Patent Publication (Kokai) No. 3-174368 discloses an alumina raw material of 10 to 82% by weight and a Mg particle having a particle size of 0.3 mm or more.
The O · Al ₂ O ₃ spinel raw material 10 to 70% by weight and mixtures of alumina cement 8-20% by weight, particle size 1
Disclosed is an alumina / spinel pouring material characterized by containing 10 to 40% by weight of crushed alumina particles having an outer diameter of 0 to 50 mm. This publication discloses that crack extension can be suppressed by adding alumina crushed particles.

[0009]

However, when a spinel raw material is added to an alumina-based amorphous refractory, if the particle diameter of the spinel raw material is about 1 mm to 75 μm, the effect of improving the slag infiltration resistance is still insufficient. Not enough. When a large amount of spinel raw material having a particle size of 5 μm or less is used, although the slag infiltration resistance is improved, the linear change rate after heating tends to shrink, the heat resistance spalling property is inferior, and cracks and the like are liable to occur. This causes problems such as a decrease in performance.

[0010] Accordingly, an object of the present invention is to provide an alumina / spinel amorphous refractory having more excellent slag infiltration resistance than conventional ones, and having heat resistance spalling property by imparting residual expansion after heating. Is to do.

[0011]

That is, according to the present invention, a particle size of 7
1% by weight or more and less than 5% by weight of fine spinel powder of 5 μm or less,
However, the content of spinel ultrafine powder of 5 μm or less is 1% by weight.
Less, alumina cement 2-20% by weight, particle size 0.3m
m and less than 15% by weight of alumina fine powder, and the remainder is made of an alumina-spinel irregular shaped refractory comprising an alumina raw material having a particle size of more than 0.3 mm and 8 mm or less.

Further, the present invention relates to an alumina-rich spinel having a content of ultrafine spinel powder having a particle size of 75 μm or less, 1% by weight or less and less than 5% by weight; Raw material 60% by weight or less, alumina cement 2 to 20% by weight, particle size 0.3mm
The present invention relates to an alumina / spinel amorphous refractory, characterized in that the following alumina fine powder is 15 to 40% by weight, and the balance is made of an alumina-based material having a particle size of more than 0.3 mm and 8 mm or less.

Further, the alumina-spinel amorphous refractory of the present invention includes crushed particles of fused alumina, sintered alumina pellets, crushed particles of fused spinel, sintered spinel pellets, crushed particles of ban shale, and alumina brick. Particle size of one or more selected from the group consisting of crushed grains
m can be compounded in an amount of 10 to 40% by weight on the outer surface.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention makes it possible to achieve both slag infiltration resistance and heat-resistant spalling resistance by specifying the particle size and the mixing ratio of spinel raw materials used for alumina / spinel amorphous refractories. This solves the conventional problems.

Here, the particle diameter of the spinel fine powder used in the present invention is 75 μm or less, and the blending ratio of the spinel fine powder having a particle diameter of 75 μm or less is 1% by weight or more and less than 5% by weight. In slag proportion of the spinel fines less than 1 wt.% FeO, invasion suppression of MnO component is not sufficient, CaO in the slag is 5% by weight or more, invasion suppression of components such as SiO ₂ is not sufficient. This is considered for the following reasons.

Since spinel suppresses slag infiltration by dissolving components such as FeO and MnO in slag, the specific surface area per the same weight increases as the particle size decreases, and the effect of suppressing infiltration increases. However, spinel does not have the ability to suppress infiltration of components such as CaO and SiO _{2 in} slag, and it is considered that alumina suppresses these. On the other hand, under conditions where spinel and alumina coexist, alumina solid-dissolves in spinel with heating, and under conditions where alumina cement and alumina coexist, CaO, which is the main component of alumina cement with heating,・ Al ₂
O ₃ has a known be a CaO · 6Al ₂ O ₃ composition react with the alumina. From these facts, in the alumina / spinel amorphous refractory, the alumina in the fine powder portion is indispensable for suppressing the infiltration of components such as CaO and SiO ₂ in the slag, but it is equivalent to spinel and alumina cement in the heating stage before use. It can be seen that the amount has been consumed. For this reason, the spinel fine powder needs to be added to a composition containing sufficient alumina fine powder, and the optimal amount of the spinel fine powder is 1% by weight or more and less than 5% by weight.

Further, in the amorphous refractory of the present invention,
The content of the ultrafine spinel powder having a particle size of 5 μm or less needs to be less than 1% by weight. This is because when the content of the ultrafine spinel powder having a particle size of 5 μm or less is 1% by weight or more, the linear change rate after heating tends to shrink, and the heat-resistant spalling property decreases due to over-sintering, which easily causes cracks and the like. That's why.

This tendency can be observed from the results shown in FIG. That is, FIG. 1 shows that the compounded amount of the sintered alumina is 86% by weight, the compounded amount of the alumina cement is 10% by weight, the sintered spinel fine powder having a particle size of 75 to 5 μm and the particle size of 5 μm
The total amount of the following sintered spinel ultrafine powder was set to 4% by weight, and the specimens obtained by variously changing the ratio of the sintered spinel fine powder and the sintered spinel ultrafine powder therein after heating at 1500 ° C. for 3 hours were used. It is a graph which shows a line change rate. Here, the plot is sintered spinel fine powder 3.6% by weight, sintered spinel ultrafine powder 0.4% by weight, the plot is sintered spinel fine powder 3.4% by weight, sintered spinel ultrafine powder 0.6% by weight, plot Is sintered spinel fine powder 2.5% by weight, sintered spinel ultrafine powder 1.
5% by weight, plot: sintered spinel fine powder 2% by weight, sintered spinel ultrafine powder 2% by weight, plot: sintered spinel fine powder 1% by weight, sintered spinel ultrafine powder 3% by weight, plot: sintered spinel ultrafine powder 4 % By weight. From the results shown in FIG. 1, it can be seen that when the blending ratio of the sintered spinel ultrafine powder is 1% by weight or more, the linear change rate after heating of the test sample shows a tendency to shrink. Therefore, the content of the ultrafine spinel powder having a particle diameter of 5 μm or less in the fine powder of spinel having a particle diameter of 75 μm or less is preferably as small as possible. However, when an amorphous refractory is actually compounded as a product, it is completely within the range of 75 to 5 μm. It is impossible to use the classified spinel fine powder in terms of cost, and spinel ultrafine powder is inevitably mixed. In this case, the mixing ratio of the spinel ultrafine powder is less than 1% by weight based on the total amount of the amorphous refractory. It can be seen that the amount is acceptable.

Here, the fine spinel powder used in the present invention may be either an electrofused product or a sintered product. The component ratio in the spinel is preferably approximately the theoretical composition of Al ₂ O ₃ : MgO = 7: 3, but the Al ₂ O ₃ component is slightly lower than the theoretical composition.
(For example, about 10% by weight) Although there is no problem even if it is large, MgO
If the amount of the component is larger than the theoretical composition, it is not preferable because digestion resistance is poor.

The alumina / spinel amorphous refractory of the present invention contains 2 to 20% by weight, preferably 8 to 20% by weight of alumina cement. As the alumina cement, those conventionally used as a pouring material can be used.

Next, alumina fine powder having a particle size of 0.3 mm or less is added to and blended with the alumina / spinel amorphous refractory of the present invention. The compounding amount of the alumina fine powder is 15 to 40% by weight. When the blending amount of the alumina fine powder is less than 15% by weight, the effect of the addition is not exhibited, which is not preferable.
On the other hand, when the content exceeds 40% by weight, the amount of added water is undesirably increased when the refractory is constructed as an irregular shaped refractory. As the alumina fine powder, sintered alumina fine powder, fused alumina fine powder and the like can be used.

Further, the alumina raw material constituting the remainder of the alumina / spinel amorphous refractory of the present invention is selected from artificial raw materials such as sintered alumina and electrofused alumina and natural raw materials such as bauxite and ban shale. One or two
More than species can be used. However, since an increase in SiO ₂ causes the generation of a low-melting substance, it is desirable to use sintered alumina or electrofused alumina. The particle size of the alumina raw material is more than 0.3 mm and 8 mm or less.

In another embodiment of the present invention, a particle size of 75 μm
By using the following spinel fine powder and alumina-rich composition spinel raw material with a particle size of 1 mm or more, it is possible to impart residual expansion after heating without impairing slag infiltration resistance, and further improve heat-resistant spalling properties Becomes

The alumina-rich composition spinel raw material having a particle diameter of 1 mm or more is used as an aggregate of alumina / spinel amorphous refractory. The composition of the alumina-rich composition spinel raw material has an Al ₂ O ₃ content of 80% by weight or more, and its mineral phase is spinel or a coexistence type of spinel and colantam. When the particle size is less than 1 mm, the effect of imparting residual expansion after heating is small, and the composition is A
If Al ₂ O ₃ is less than l ₂ O ₃ : MgO weight ratio = 80: 20, it is not preferable because slag infiltration increases. The mixing ratio of the alumina-rich composition spinel material is set to 60% by weight or less. When the blending ratio of the alumina-rich composition spinel material exceeds 60% by weight, the amount of the aggregate increases,
As a result, the fine powder is insufficient, and the fluidity of the irregular-shaped refractory is lowered, which is not preferable because the workability is impaired.

In yet another embodiment of the present invention, wherein the particle size is 75
1% by weight or less and less than 5% by weight of fine spinel powder having a particle size of 1 μm or less, with the exception that the content of ultrafine powder of spinel having a particle size of 5 μm or less is less than 1% by weight, 2-20% by weight of alumina cement, and the balance being alumina / spinel amorphous 1% by weight or more and less than 5% by weight of refractory or spinel fine powder having a particle size of 75 μm or less, provided that the content of ultrafine powder of spinel having a particle size of 5 μm or less is less than 1% by weight and 60% by weight or less of an alumina-rich spinel raw material having a particle size of 1 mm or more , Alumina cement 2
Alumina-spinel amorphous refractory composed of 20% by weight, with the balance being alumina raw material, was prepared by adding fused alumina crushed particles, sintered alumina pellets, fused alumina spinel crushed particles having a particle size in the range of 10 to 50 mm. One or two or more coarse grains selected from the group consisting of sintered spinel pellets, crushed granite shale grains and crushed alumina bricks are subjected to 10
Addition of up to 40% by weight can suppress crack elongation.

The alumina-spinel amorphous refractory of the present invention having the above-mentioned compounding ratio is 4 to 8 weight by weight with respect to a predetermined amount of water, for example, the alumina-spinel amorphous refractory of the present invention. %, Preferably about 5 to 8% by weight.

[0027]

EXAMPLES The alumina / spinel amorphous refractory of the present invention will be further described below with reference to examples. Table 1 shows the chemical components of the raw materials used in the examples, and Table 2 shows the examples in comparison with comparative examples. Each composition shown in Table 2 was added with predetermined water, kneaded, poured into a metal frame having a sample shape determined for each test, molded and cured at 20 ° C. for 24 hours,
After drying at 105 ° C. for 24 hours, they were subjected to the following tests.

The linear rate of change after heating is the result after treatment at 1500 ° C. for 3 hours in accordance with JIS R2555. In this test, the sample shape was 40 mm × 40 mm.
× 160 mm.

The erosion test was performed under the following conditions. (1) Apparatus: Rotary drum erosion test apparatus (2) Sample shape: 50 mm x 200 mm x 65 mm (3) Temperature / time: 1650 ° C-4 hours, slag exchange every 1 hour (4) Slag: converter slag (CaO / (SiO ₂ = 3.65) 1.2 kg / cycle The erosion depth index and the immersion depth index are shown in Comparative Example 1 in Table 3.
The erosion depth dimension and the infiltration depth dimension of the sample are 100. The smaller the numerical value, the better the corrosion resistance and the infiltration resistance.

The spalling test was performed under the following conditions. (1) Test method: panel spalling method (2) Sample shape: 65 mm x 114 mm x 230 mm (3) Temperature / time: heating at 1500 ° C for 30 minutes-cooling 30
Min, 10 cycles (4) Evaluation method: −-low crack generation, ○ -medium crack generation, △
-Slight crack generation Many results are shown in Tables 2 and 3.

[0031]

[Table 1]

[0032]

[Table 2]

[0033]

[Table 3]

[0034]

[Table 4]

REFERENCE EXAMPLE The results of applying the above-mentioned present invention product and the comparative product to an actual furnace are shown below: A steelworks side wall life The comparative product 5 has 250 charges, whereas the comparative product 5 has 300 charges. there were. B steelworks side wall life The comparative product 16 had 150 charges, whereas the present invention product 3 had 200 charges. B steel plant floor life The comparative product 13 had 125 charges, whereas the present invention product 6 had 160 charges.

[0036]

As described above, according to the present invention, 1% by weight or more and less than 5% by weight of spinel fine powder having a particle size of 75 μm or less is added to the alumina / spinel amorphous refractory.
Alumina spinel having more excellent slag infiltration resistance than before by setting the content of spinel ultrafine powder of 1 μm or less to less than 1% by weight, and having heat resistant spalling property by imparting residual expansion after heating. An effect is provided that a refractory of irregular quality can be provided.

[Brief description of the drawings]

FIG. 1 shows the blending amount of spinel ultrafine powder having a particle size of 5 μm or less in alumina / spinel irregular shaped refractory and 15
It is a graph which shows the relationship of the linear change rate after heating at 00 degreeC for 3 hours.

Claims (3)

(57) [Claims] 1. A spinel fine powder having a particle size of 75 μm or less, 1% by weight or more and less than 5% by weight, provided that the content of a spinel ultrafine powder of 5 μm or less is less than 1% by weight, alumina cement 2-20%
Alumina fine powder having a particle size of 0.3 mm or less by weight, 15 to 40
% By weight, and the balance being made of an alumina raw material having a particle size of more than 0.3 mm and 8 mm or less.
Spinel amorphous refractories. 2. 1% by weight or more and less than 5% by weight of spinel fine powder having a particle size of 75 μm or less, provided that the content of ultrafine spinel powder having a particle size of 5 μm or less is less than 1% by weight and 60% by weight of an alumina-rich composition spinel raw material having a particle size of 1 mm or more. % Or less, 2 to 20% by weight of alumina cement, 15 to 40% by weight of fine alumina powder having a particle size of 0.3 mm or less, and the remainder is made of an alumina raw material having a particle size of more than 0.3 mm and 8 mm or less. Alumina / spinel amorphous refractory. 3. One or two kinds selected from the group consisting of fused alumina crushed grains, sintered alumina pellets, fused spinel crushed grains, sintered spinel pellets, crushed shale granules, and crushed alumina bricks. The above particle size is 10-50m
The alumina / spinel amorphous refractory according to claim 1 or 2, which contains 10 to 40% by weight of coarse particles of m in outer diameter.