JP2003252686A - Refractory - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide refractories such as cast material that is excellent in corrosion resistance and generates less cracking, having a long service life. <P>SOLUTION: The refractories comprise a CaO content of 0.5% by mass or less, a total amount of lactic acid and glycolic acid of 0.005-1% by mass and the remainder of Al<SB>2</SB>O<SB>3</SB>, SiO<SB>2</SB>, MgO and carbon. The refractories is a formulation of 3-15% by mass of an alumina super fine powder having an average particle size of 1.5 μm or less, 0.01-2% by mass of aluminum lactate or glycolic acid/aluminum lactate and 0.01-3% by mass of a lightly calcined magnesia having an iodine absorption amount of 20 iodine mg/g or more and an average particle size of 1 μm or less. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refractory material for pouring construction.

[0002]

2. Description of the Related Art Casting refractories (hereinafter referred to as "casting materials"), which are used as refractory materials for molten steel vessels such as molten steel ladle, tundish, vacuum degassing furnace, or molten steel processing equipment, are widely used. . For example, Patent Document 1 and the like propose an alumina-magnesia casting material.

However, the operating conditions of the molten steel container and the molten steel processing apparatus in recent years are becoming severer by increasing the temperature of molten steel, extending the time of staying in molten metal, stirring by blowing gas, etc., and high durability such as alumina-magnesia Even if it is a durable material, its life is by no means sufficient, and there is a strong demand for casting materials with excellent durability.

As a measure for improving it, Patent Document 1 proposes an alumina-magnesia casting material in which aluminum lactate is added to a binder. Here, aluminum lactate is used as the binder, and alumina cement, which is a CaO source, and silica, which is a SiO ₂ source, are removed, thereby obtaining an effect of improving melt damage resistance and heat spalling resistance by suppressing sintering. Further, Patent Document 2 also proposes an alumina-magnesia casting material in which aluminum lactate is added to a binder as a material for wet spraying and alumina cement which is a CaO source is removed.

[0005]

[Patent Document 1] Japanese Patent Laid-Open No. 11-130550

[Patent Document 2] Japanese Unexamined Patent Publication No. 10-194853

[0006]

However, in the case of alumina-magnesia, the removal of alumina cement and silica reduces the production of low-melting-point substances, which slows the spinel-forming reaction between alumina and magnesia. There is a problem that internal cracking or peeling damage due to expansion stress occurs due to rapid expansion during the formation reaction.

Further, if alumina cement and silica are removed, the formation of low melting point substances is suppressed, and the formation of low melting point substance layers at the contact boundary with slag during use of refractory materials is reduced. Poor effect of preventing polling suppression. As a result, sufficient durability cannot be obtained due to peeling damage due to structural spalling and the cracks.

When the construction is carried out by spraying as in Japanese Patent Application Laid-Open No. 10-194853, the structure of the construction body is relatively porous, so that the contact area between the particles of alumina and magnesia is small, so that the spinel formation reaction occurs. Since the porous structure has a slow expansion function to expand and absorb, the alumina sponge and silica are removed to suppress the sintering, so that the heat-resistant spalling property can be obtained.

On the other hand, in the pouring construction using a mold such as a core, the structure of the construction body is dense, and a material having only cement removed cannot avoid a rapid expansion, and has an actual complex shape. Internal cracks or peel damage due to expansion stress occur in the lining of the molten steel container or the molten steel processing apparatus.

When aluminum lactate is used as the binder except alumina cement or silica,
Probably because the shrinkage cracks that occur during curing cannot be suppressed, defects occur in the construction body. These cracks facilitate penetration of slag and molten steel into the internal structure during use of the refractory, and are therefore less effective in preventing structural spalling suppression. As a result, sufficient durability cannot be obtained due to peeling damage due to structural spalling and the cracks.

The present invention provides a casting material which can prevent peeling damage and the occurrence of cracks and can obtain sufficient durability.

[0012]

[Means for Solving the Problems]
Therefore, the present invention has the following structures. (1) 0.5% by mass or less of CaO, lactic acid and glycolic acid
Of 0.005 to 1 mass% and MgO of 0.01 to 3
2 mass%, SiO₂Is 0.05 to 50% by mass, and the balance is A
l₂O₃And other unavoidable ingredients
And refractory. (2) CaO is 2% by mass or less, and lactic acid and glycolic acid are combined.
Amount 0.005-1% by mass, Al₂O₃Is 0.1 to 45
Mass%, SiO₂Is 0.05 to 5% by mass, and the balance is MgO
And other unavoidable components
Fireworks. (3) CaO 0.5 mass% or less, lactic acid and glycolic acid
Of 0.005 to 1% by mass, ZrO₂Is 10 to 70
Mass%, SiO₂Is 5 to 50 mass% and MgO is 0.01
~ 5% by mass, balance Al₂O₃And other unavoidable achievements
A refractory material characterized by being composed of minutes. (4) CaO 0.5 mass% or less, lactic acid and glycolic acid
Of 0.005 to 1% by mass and carbon of 1 to 44% by mass
%, SiO₂0.1 to 90% by mass, SiC 1 to 80
% By mass, 0.01 to 10% by mass of MgO, the balance being Al₂
O₃And other unavoidable components
Refractory. (5) CaO is 2% by mass or less, and lactic acid and glycolic acid are combined.
Amount is 0.005 to 1% by mass, carbon is 0.5 to 30% by mass
%, SiO₂Is 0.05 to 20 mass%, Al₂O ₃But
0.1 to 15% by mass, balance MgO and other unavoidable
Refractory characterized by being composed of various components. (6) Alumina ultrafine powder having an average particle diameter of 1.5 μm or less is 3 to
15 mass% aluminum lactate, glycolic acid lactate
One of the aluminum and aluminum glycolates
Rui or two or more kinds in a total amount of 0.01 to 2 mass% and iodine
Adsorption amount of 20 iodine mg / g or more and average particle size of 1 μm or less
Contains 0.01-3% by mass of the following light-burned magnesia fine powder
Any one of the above (1) to (5), characterized in that
It is a refractory material as described in the item.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is characterized in that no alumina cement serving as a CaO source is used for the purpose of improving corrosion resistance and heat-resistant spalling resistance. The CaO component is unavoidably contained in refractory raw materials other than alumina cement, but has a smaller effect on corrosion resistance and spalling resistance than the CaO component intentionally added due to alumina cement. It is considered that this is because the CaO component in the refractory raw material is a stable compound, whereas the CaO component in the alumina cement is unstable and reacts with the surrounding aggregate and the like by receiving heat. In the present invention, attention was paid to the CaO component derived from alumina cement, which has a large adverse effect, and by eliminating this, a highly durable refractory material was obtained.

The CaO content of the refractory material of the present invention is set to a value in excess of these unavoidable amounts and without intentional addition of CaO. That is, CaO components derived from refractory raw materials other than alumina cement are usually 0.5% by mass or less when alumina-based, alumina-silica-based, spinel-based, silica-based, zircon-based, and zirconia-based raw materials are mainly used, In the case of magnesia-based raw materials, these values are less than 2% by mass.
The upper limit of the O content is set. Also, although relatively small,
Since CaO in the refractory raw material cannot be ignored, it is necessary to regulate the CaO content to a predetermined amount or less.

The total amount of lactic acid and glycolic acid in the refractory material of the present invention is 0.005 to 1% by mass. This is an amount corresponding to the added amount of 0.01 to 2% by mass of aluminum lactate, aluminum glycolate lactate, aluminum glycolate, etc. described later. Aluminum lactate, glycolic acid aluminum lactate, and aluminum glycolate are composed of lactic acid, glycolic acid, and aluminum ions (aluminum oxide when expressed as an oxide). Therefore, the amount of lactic acid or glycolic acid is aluminum lactate, aluminum glycolate lactate, glycol It becomes less than the addition amount of aluminum acid salt. The amount of lactic acid or glycolic acid was 0.
If it is less than 005 mass%, there is no effect of generation of fine cracks due to expansion and contraction, and if it exceeds 1 mass%, cracks due to curing shrinkage occur and the problem of reduced corrosion resistance occurs.

From the viewpoint of the chemical composition of refractories, Al
₂ O _3, SiO _2, 0.5 wt% CaO is the case of many refractories such as ZrO ₂ or less, In the case of more refractory of MgO CaO 2 wt% or less, total amount of lactic acid and glycolic acid It is 0.005 to 1 mass%.

The chemical composition and composition of various refractories will be described below. The invention according to (1) above is a refractory containing a large amount of Al ₂ O ₃ component and containing alumina-based or alumina-silica-based raw material as a main component, that is, alumina-magnesia, alumina-spinel, alumina-spinel magnesia,
It is a high-alumina refractory material whose chemical composition is CaO.
Is 0.5% by mass or less, and the total amount of lactic acid and glycolic acid is 0.
005 to 1 mass%, MgO 0.01 to 32 mass%, S
iO ₂ is 0.05 to 50% by mass, and the balance is Al ₂ O ₃ and other unavoidable components. The reason for defining the total amount of CaO, lactic acid and glycolic acid in this way is as described above.

MgO is derived from lightly burned magnesia, magnesia-based raw materials, dolomite-based raw materials, spinel-based raw materials, and the like.
If the amount of gO is less than 0.01% by mass, the shrinkage control during curing is not sufficient, and if it exceeds 32% by mass, magnesia hydrates, causing problems such as cracks in the construction body and increased slag infiltration. .

SiO ₂ is derived from silica-based raw materials such as volatile silica and alumina-silica-based raw materials. If it is less than 0.05% by mass, the thermal shock resistance of the construction body is deteriorated and magnesia is hydrated. If it exceeds 50% by mass, the corrosion resistance deteriorates.

The balance is Al₂O₃And other unavoidable achievements
Minutes. Al₂O₃Is an alumina type, alumina-silica
It originates from each raw material, such as those based on the system and spinel. Inevitable ingredients
Is iron oxide, MnO, TiO₂, Na₂O, P₂O_Five,
V ₂O_FiveOr oxides with stable nuclides such as C, C
Although these are compounds such as
Therefore, it is preferably 5% by mass or less.

When the amounts of lactic acid and glycolic acid in the refractory are controlled, the performance of the refractory can be managed and grasped more accurately than the ratio of aluminum lactate, aluminum glycolate lactate, aluminum glycolate, etc., which will be described later, is controlled. You can This is because commercially available aluminum lactate, aluminum glycolate lactate, and aluminum glycolate contain diluents, fillers, and the like, and the amounts of components such as aluminum lactate are not constant.

In the present invention, the following method was used to measure the amounts of lactic acid and glycolic acid in the refractory. That is, in accordance with the method for elution test of soil, etc. of Notification No. 46 of the Environment Agency, a sample of 2 mm or less and pure water adjusted to pH 5.8 to 6.3 were used in a volume ratio of 10% (sample 50 g and pure water 500 ml). Mix at a ratio and shake at room temperature and pressure (shaking width 4-5c
m, 200 times per minute) and shake continuously for 6 hours. This solution was allowed to stand for 30 minutes, centrifuged at about 3000 rpm, and the supernatant was filtered with a membrane filter having a pore size of 0.45 μm to obtain a measurement solution.

This was measured by capillary zone electrophoresis or high performance liquid chromatography. In the capillary zone electrophoresis method, a fused silica capillary was used, and the sample injection was performed by the drop method. Detection was by UV absorption by the on-column method. In the high performance liquid chromatography method, an ordinary column having an inner diameter of 3 to 4 mm is used and the flow rate is 0.
The ultraviolet absorptivity was measured at a flow rate of about 5 to 2 ml / min. Capillary electrophoresis is superior in detection sensitivity.
The difference between the two results was within 20%.

The present invention according to (2) above is a refractory material such as magnesia or magnesia spinel, which has a large amount of MgO component, and its composition is such that CaO is 2% by mass or less and the total amount of lactic acid and glycolic acid is 0. 0.005 to 1 mass%, Al ₂ O ₃
Is 0.1 to 45% by mass, SiO ₂ is 0.05 to 5% by mass, and the balance is MgO and other unavoidable components.

Al ₂ O ₃ is derived from ultrafine alumina powder, alumina-based raw material, spinel-based raw material, etc., and is required to be 0.1% by mass or more for suppressing slag infiltration and imparting strength, but if it exceeds 45% by mass, corrosion resistance is increased. descend.

SiO ₂ is derived from silica-based raw materials and magnesia-based raw materials, and is used in an amount of 0.05 mass% to prevent hydration of magnesia.
Is necessary, but if it exceeds 5% by mass, the corrosion resistance decreases.

The balance is MgO and other unavoidable components. MgO is derived from lightly burned magnesia, magnesia-based raw materials, dolomite-based raw materials, spinel-based raw materials, and the like. Inevitable components are iron oxide, MnO, TiO ₂ , Na ₂ O, P ₂
An element having a stable nuclide such as O ₅ , V ₂ O ₅ , B ₂ O ₃ and C, or a compound such as an oxide is preferably used in an amount of 5 mass% or less so as not to impair the corrosion resistance.

The present invention according to (3) above is a refractory material containing a large amount of zircon or zirconia, and its chemical composition is C
aO is 0.5% by mass or less, the total amount of lactic acid and glycolic acid is 0.005 to 1% by mass, ZrO ₂ is 10 to 70% by mass,
SiO ₂ is 5 to 50 mass%, MgO is 0.01 to 5 mass%, and the balance is Al ₂ O ₃ and other unavoidable components.

ZrO ₂ is derived from zircon or zirconia, and if it is less than 10% by mass, sufficient corrosion resistance cannot be obtained. If it exceeds 70% by mass, the spalling resistance may be deteriorated.

SiO ₂ is derived from silica-based or alumina-silica-based raw materials. If SiO ₂ is less than 5% by mass, spalling resistance is deteriorated, and if it exceeds 50% by mass, corrosion resistance is deteriorated.

MgO is derived from lightly burned magnesia, magnesia-based raw materials, dolomite-based raw materials, spinel-based raw materials, etc.
If it is less than 0.01% by mass, the light-burning magnesia is insufficient and the curing shrinkage suppressing effect is insufficient. If it is 5% or more, the corrosion resistance is adversely affected.

The balance is Al ₂ O ₃ and other unavoidable components. Al ₂ O ₃ is derived from alumina, alumina-silica, spinel, and other raw materials. The unavoidable component is an element having a stable nuclide such as iron oxide, TiO ₂ , Na ₂ O, V ₂ O ₅ , P ₂ O ₅ or a compound such as oxide, and is preferably 5% by mass so as not to deteriorate the corrosion resistance. Below.

The present invention according to (4) above relates to a refractory material containing a large amount of alumina, silica, carbon and silicon carbide, wherein CaO is 0.5% by mass or less, and the total amount of lactic acid and glycolic acid is 0.005. ~ 1% by mass, carbon is 1 to 44% by mass,
SiO ₂ is 0.1 to 90 mass%, SiC is 1 to 80 mass%, MgO is 0.01 to 10 mass%, and the balance is Al ₂ O _3.
And other unavoidable ingredients.

Carbon is derived from carbon itself and silicon carbide-based raw materials, and if it is less than 1% by mass, the slag infiltration resistance and corrosion resistance are lowered, and if it exceeds 44% by mass, oxidative wear is increased.

SiO ₂ is derived from both alumina-silica and silica-based raw materials and silicon carbide-based raw materials. If it is less than 0.1% by mass, sinterability is insufficient and hot strength is difficult to develop, and if it exceeds 90% by mass. Then, the corrosion resistance deteriorates.

SiC is derived from a SiC-based raw material and is 1% by mass.
If it is less than 80% by weight, the corrosion resistance is insufficient, and if it exceeds 80% by mass, oxidative wear may occur.

MgO is derived from lightly burned magnesia, magnesia-based raw material, dolomite-based raw material, spinel-based raw material, etc.
If it is less than 0.01% by mass, shrinkage during curing cannot be sufficiently suppressed, and if it exceeds 10% by mass, slag infiltration increases.

The balance is Al ₂ O ₃ and other unavoidable components. Al ₂ O ₃ is derived from alumina ultrafine powder, alumina, alumina-silica, silica and spinel raw materials. Other components are iron oxide, TiO ₂ , Na ₂ O, V ₂ O ₅ , P
An element having a stable nuclide such as ₂ O ₅ or a compound such as an oxide is preferably used so as not to impair the corrosion resistance.
It should be less than or equal to mass%.

The present invention according to (5) above is a refractory material containing a large amount of magnesia and carbon, the chemical composition of which is 2% by mass or less of CaO, and the total amount of lactic acid and glycolic acid is 0.005-1.
Mass%, carbon 0.5 to 30 mass%, SiO ₂ 0.0
5 to 20 mass% and Al ₂ O ₃ 0.1 to 15 mass%, with the balance being MgO and other unavoidable components.

If the amount of carbon originating from organic substances such as carbonaceous raw materials and resins is less than 0.5% by mass, slag infiltration is large, and if it exceeds 30% by mass, oxidative wear is large.

If the SiO ₂ content is less than 0.05% by mass, magnesia will hydrate, and if it exceeds 20% by mass, the corrosion resistance will decrease.

When Al ₂ O ₃ is less than 0.1% by mass, sufficient strength is not exhibited, and when it is 15% by mass or more, corrosion resistance is deteriorated.

The balance is MgO and other unavoidable components.
MgO is derived from lightly burned magnesia, magnesia, dolomite, and spinel raw materials. Other unavoidable components are iron oxides and Mn derived from the above-mentioned respective raw materials, boride, glass powder, metal powder and binder, hardening modifier and the like.
It is an element having a stable nuclide such as O, P ₂ O ₅ , B ₂ O ₃ or a compound such as an oxide, and is preferably 10% by mass or less in order not to lower the corrosion resistance.

In the invention according to the above (6), ultrafine alumina powder, one or more of aluminum lactate, aluminum glycolate lactate and aluminum glycolate, and light burned magnesia fine powder are added without blending alumina cement. To do. In other words, the strength after curing is ultrafine alumina powder,
It is secured by aluminum lactate, aluminum glycolate lactate, and aluminum glycolate, and cracking during curing is suppressed by lightly baked magnesia fine powder.

The ultrafine alumina powder imparts strength to the construction body due to its cohesive force. Further, since the structure is densified, the corrosion resistance and the slag infiltration resistance are improved. In the invention according to (6),
Alumina ultrafine powder having an average particle size of 1.5 μm or less is combined. This is to increase the filling property of the matrix portion of the structure of the construction body, thereby eliminating extra voids between particles and preventing shrinkage cracks due to gelation of aluminum lactate, aluminum glycolate lactate, and aluminum glycolate described later. The effect of will be more certain.

The amount of ultrafine alumina powder is 10
The proportion of 0 mass% is 3 to 15 mass%, and the average particle size is 1.5 μm or less. The ratio of alumina ultrafine powder is 3
When the content is less than mass%, the effect of preventing shrinkage cracks of the construction body is poor, and 1
If it exceeds 5% by mass, the spinel reaction will be excessive, possibly leading to a decrease in spalling resistance. If the average particle size exceeds 1.5 μm, the expected filling properties and the strength of the construction product cannot be obtained.

As the ultrafine alumina powder, it is preferable to use calcined alumina because it is easily available from commercial products. Calcined alumina is known to have various particle sizes. In the present invention, as long as 3 to 15 mass% of alumina ultrafine powder having an average particle diameter of 1.5 μm or less is used, alumina ultrafine powder having another particle diameter may be combined. Further, a plurality of alumina ultrafine powders having different particle diameters may be combined in the range of an average particle diameter of 1.5 μm or less.

Aluminum lactate, aluminum glycolate lactate, and aluminum glycolate play a role as a binder for hardening the casting material during curing by gelation caused by the reaction with working water, and due to the expansion and contraction accompanying the gelation. Causes microscopic cracks to form in the construction body structure. The fine cracks remain in the tissue when the construction body is dried and heated, and thus they effectively function to impart air permeability, absorb expansion, and relax thermal stress.

The amount of aluminum lactate, aluminum glycolate lactate and aluminum glycolate added was 0.
If it is less than 01% by mass, the effect of expansion and absorption is not obtained, and if it exceeds 2% by mass, the corrosion resistance is lowered. Further, the addition may be carried out in a state of being previously thawed with water. Furthermore, by adding lightly burned magnesia, desired effects of volume stability and corrosion resistance can be obtained. The reason is considered as follows.

The fine cracks due to the gelling reaction of aluminum lactate, aluminum glycolate lactate, and aluminum glycolate are effective for the expansion and absorption of the construction body as described above, but at the same time, the cracks due to curing shrinkage occur. The crack due to the curing shrinkage has a much larger crack width than the fine crack caused by the gelation reaction, and causes a decrease in corrosion resistance.

On the other hand, when light burned magnesia is combined, aluminum lactate, aluminum glycolate lactate, and aluminum glycolate are adsorbed to Mg eluted from the light burned magnesia at the time of kneading, and aluminum lactate and aluminum lactate glycolate are adsorbed. By suppressing the rapid gelation reaction observed when aluminum glycolate is used alone, shrinkage cracks during curing are prevented.

Further, there is a curing form in which magnesia and alumina are already combined at the time of curing due to the reaction of light-burned magnesia with aluminum lactate, aluminum lactate glycolate, and aluminum glycolate, and these are spinelized at a relatively low temperature range. The spinel produced here has a very fine grain size. This, together with the prevention of shrinkage cracks during curing, contributes greatly to the improvement of corrosion resistance and volume stability.

These effects according to the present invention are obtained by adsorbing iodine of 20 iodine mg / g or more, more preferably 30 to 200 iodine mg / g, and having an average particle diameter of 1 μm or less, even more preferably 0.00, among light burned magnesia. It is only demonstrated when using light-burned magnesia fine powder of 5 μm or less. The amount of iodine adsorbed on lightly burned magnesia powder is 20 iodine m
If it is less than g / g, the reaction with aluminum lactate, aluminum lactate glycolate, and aluminum glycolate is inferior, so that there is no effect in preventing shrinkage cracks during curing. Also,
When the amount of iodine adsorbed on the lightly burned magnesia fine powder exceeds 200 iodine mg / g, the hydration reaction is likely to occur and the digestion resistance of the refractory structure tends to be deteriorated, which is not preferable.

If the average particle size exceeds 1 μm, the reaction with aluminum lactate, aluminum glycolate lactate and aluminum glycolate is slow even if the iodine adsorption amount is 20 iodine mg / g or more. No effect of preventing shrinkage cracks. Even if either the iodine adsorption amount or the average particle size of the lightly baked magnesia fine powder deviates from this range, the effect aimed at by the present invention cannot be obtained.

The iodine adsorption amount can be measured in accordance with JIS-K6338, which is a method for measuring the surface properties of fine magnesia powder. The average particle size can be measured by a laser diffraction method. Further, the particle size of ultrafine alumina powder, which will be described later, can also be measured by a laser diffraction method.

If the amount of the lightly burned magnesia fine powder is less than 0.01 mass% relative to 100 mass% of the refractory aggregate composition, there is no effect of preventing curing shrinkage. If it exceeds 3% by mass, the pouring material will have high viscosity during kneading, and the fluidity during construction will decrease, making it difficult to obtain a dense construction body.

The lightly burned magnesia fine powder is obtained by calcining magnesium hydroxide in a relatively low temperature range, and the iodine adsorption amount varies depending on the particle size adjustment, the calcining temperature and other operations in the manufacturing process. Various qualities of iodine adsorption amount and particle size are commercially available, and the light burned magnesia fine powder used in the present invention can also be obtained from this commercially available product. Further, if the light-burning magnesia fine powder having the iodine adsorption amount and the particle size limited in the present invention is used in the amount in the range limited in the present invention, the light-burning magnesia fine powder having another iodine adsorption amount and the particle size is used in combination. You may.

The aluminum lactate includes aluminum lactate in a narrow sense, and includes, for example, basic aluminum lactate and aluminum citrate lactate as described in JP-A-9-194264. For example, basic aluminum lactate is produced by reacting water-soluble aluminum with carbonic acid or a carbonate or the like and lactic acid. As aluminum lactate, one having a molar ratio of Al ₂ O ₃ / lactic acid of 0.3 to 2 is preferable, but it is not limited to this.

Aluminum lactate glycolate is included in a broad sense of aluminum lactate. For example, it can be obtained by preparing a mixed solution of aluminum lactate and glycolic acid, which is an organic acid, and then drying this. It is preferable that the molar ratio of Al ₂ O ₃ / (lactic acid + glycolic acid) is 0.3 to 2,
It is not limited to this. Aluminum glycolate has an Al ₂ O ₃ / glycolic acid molar ratio of 0.3 to 2
However, the present invention is not limited thereto.

Raw materials used for the refractory material of the present invention will be described below. The alumina raw material is a refractory raw material having both corrosion resistance and volume stability. It does not matter whether it is an electrofused product or a sintered product. For the fine powder portion, calcined alumina which is easily available as fine powder may be used. The purity of Al ₂ O ₃ is preferably 95% by mass or more. The magnesia-based raw material used in the present invention may be either a sintered product or an electromelted product. MgO purity is 9
It is 0% by mass or more, and more preferably 95% by mass. Part or all of the magnesia-based raw material used in the present invention,
A magnesium carbonate raw material having a chemical analysis value of MgO content of 35 mass% or more may be used. As magnesium carbonate, natural magnesite, synthetic magnesium carbonate, magnesium carbonate hydroxide (basic magnesium carbonate), etc. can be used.
The gO content is preferably 35% by mass or more and the particle size is preferably 1 mm or less.

The raw material of magnesium carbonate is from around 600 ° C.
Decomposition (MgCO₃→ MgO + CO ₂) By construction body
Creates microvoids in the tissue. And this fine void is
In addition to absorbing and relaxing the expansion of refractory materials, when using the construction body
Prevents oversintering of the surface layer in
Also exerts an excellent effect on. Raw magnesium carbonate
From the viewpoint of corrosion resistance, the proportion of the material is 7
0 mass% or less, or 1 in the ratio of the total refractory aggregate
It is more preferably 0% by mass or less. Particle size of magnesia raw material
Is the same as the below-mentioned alumina raw material,
Considering the fluidity or the filling property of the construction body, coarse particles, medium particles,
Adjust to fine particles.

Volatile silica and silica can be used as the silica-based raw material. Volatile silica is added to an alumina-magnesia amorphous amorphous refractory or a basic amorphous amorphous refractory, and is effective for relaxing expansion stress during spinel formation and suppressing magnesia hydration. Volatile silica is obtained, for example, as a by-product in the production of silicon or a silicon alloy, and is commercially available under the trade name of silica flour or micro silica. Ultrafine particles having an average particle size of 1 μm. It is desirable that the compounding ratio is 3% by mass or less in terms of the ratio to the entire refractory aggregate.
If it exceeds 3% by mass, a low-melting point substance is generated more and the corrosion resistance is lowered. The most preferable range is 0.05 to 1.5% by mass.

As the spinel raw material, electrofused or sintered spinel, spinel-like slag and the like can be used. Al ₂ O ₃
Impurities other than MgO and MgO are preferably less than 80 mass%. It can be used even if it is out of the stoichiometric composition.

Alumina-silica based raw material is pyrophyllite,
Clay, chamotte, sillimanite, andalusite, kyanite, natural or synthetic sintered or fused mullite,
There are shale shale and bauxite, which can be used according to the application. All may be regular products.

The zircon material is natural zircon sand,
Zircon flour can be used, and natural baddeleyite and synthetic zirconia can be used as the zirconia raw material. All of them can be regular products.

As the dolomite raw material, synthetic products and natural products can be used. Those that have been treated to enhance hydration resistance are suitable as cast refractories. As the carbonaceous raw material, those which are usually used can be used. Examples of the carbon-based raw material include scaly graphite, carbon black, anthracite, earthy graphite, electrode scrap, and powder pitch.

The carbide type raw material is a silicon carbide type raw material and the like, and as the silicon carbide type raw material, those generally used for refractories can be used. As boride, B ₄ C, Ca
B ₆ , ZrB ₂ or the like can be used. In addition, raw materials used for refractories other than these, such as glass powder, may be added.

The metal powder is added to suppress the oxidation of the carbonaceous raw material and to improve the strength of the refractory, and one or more kinds of metal aluminum, metal silicon, metal magnesium, metal calcium, or a mixture or compound thereof can be used. . The particle size is preferably 1 mm or less. For example, hydraulic alumina fine powder may be added as a binder. Unlike alumina cement, hydraulic alumina fine powder does not cause a decrease in corrosion resistance, and has an effect of preventing the work body from sticking out due to expansion.

Other peptizers known as additives for casting materials, refractory coarse particles, hardening modifiers, short metal fibers (for example, stainless steel fibers), organic fibers, ceramic fibers, carbon fibers, chrome ores, foams. Agents and the like may be added. Boric acid, lithium carbonate or the like may be added as a curing modifier. The added amount is usually 0.5% by mass or less. In particular, the addition of a deflocculant is necessary to impart fluidity during construction. As a specific example, for example, sodium tripolyphosphate, sodium hexametaphosphate, sodium ultrapolyphosphate, acidic sodium hexametaphosphate, sodium borate,
Examples include sodium citrate, a carboxyl group-containing polyether dispersant, sodium tartrate, sodium polyacrylate, sodium sulfonate, and the like. The proportion of addition is preferably 0.01 to 0.5 mass% as an external weight to 100 mass% of the refractory aggregate.

The coarse refractory particles have an effect of preventing peeling damage by cutting off the development of cracks generated in the refractory structure. Specific examples thereof include alumina, spinel, mullite, magnesia and the like. Further, it may be a brick scrap mainly made of alumina or spinel, a refractory-used product, or the like. The particle size of the coarse refractory particles is preferably in the range of 10 to 50 mm, although there is a balance with the maximum particle size of the refractory aggregate. In addition, the ratio is preferably 35% by mass or less, more preferably 5 to 30% by mass, when applied to 100% by mass of the refractory aggregate.
Is. If it exceeds 35% by mass, the strength of the construction body is deteriorated due to the unbalance of the particle size composition, and the corrosion resistance is deteriorated.

Each component in the refractory can be quantitatively analyzed by a fluorescent X-ray method using a glass bead sample. In general, carbon is heated and oxidized and analyzed as a gas.

The refractory material of the present invention can be applied not only as a casting material but also as a dry or wet spray material, a plastic refractory material, a patching material, a stamp material, a ramming material, a sling material, a coating material, a mortar and the like. . Adjust the amount and type of binders and additives as needed. The construction method may be a conventional method according to each type of refractory material. In the case of a pouring material, about 4 to 8 mass% of construction water is added to the whole of the above-described compounded composition by external application, and pouring is carried out using a mold such as a core. In addition, it is preferable to improve the filling rate by applying vibration during pouring.

[0073]

[Examples] [Example 1] Examples of the present invention conducted with a casting material and comparative examples thereof are shown below. In each example, 6.5% by mass is obtained by applying the applied water to the entire compounded composition shown in Table 1 and Table 2 on the outside.
Add and knead, pour into the formwork, and after curing, 110
A test piece was obtained by drying at a temperature of 24 hours. The CaO amount in the table is a numerical value converted as the CaO amount by multiplying the mass of each compound by the CaO concentration. As the alumina ultrafine powder in each example, calcined alumina manufactured by Showa Denko KK was used. As the volatile silica, silica flower manufactured by Elchem Co., Ltd. was used. Aluminum lactate and aluminum glycolate lactate are manufactured by Taki Chemical Co., Ltd.

The test method is as follows. Corrosion resistance; Steel piece by mass ratio: Converter slag (FeO content: 2
0 mass%) = 50:50 as erosion agent, 1700 ° C. × 5
A time rotary erosion test was performed to measure the erosion size. Slag penetration resistance: After performing a rotary erosion test under the above conditions, the slag penetration size was measured. Resistance to spalling; Steel slab by mass ratio: Converter slag (FeO
Content: 20% by mass) = 50: 50 as an erosion agent, and after heating at 1700 ° C. for 30 minutes using a rotary erosion test device, 30
After air cooling for a minute, this was repeated 6 times and the state of crack generation was observed. ⊚ has no cracks, ◯ is microcracks (having a width of hair cracks that can be visually confirmed), Δ is a small crack (crack having a width of approximately 0.3 mm or less), and × is a large crack (width is approximately 0.
Cracks of more than 3 mm) have occurred.

[0075]

[Table 1]

[0076]

[Table 2]

Each number in the comparative example is of the same material system as each number in the example of the present invention. Comparative Example 1 is an ordinary alumina-magnesia material, and Inventive Example 1 is a combination of aluminum glycol lactate lactate and light burned magnesia fine powder with alumina ultra fine powder without adding alumina cement. Hereinafter, Comparative Example 2 and Inventive Example 2 are alumina-spinel, 3 is alumina-spinel-magnesia, 4 is alumina, 5 is high alumina, 6 is magnesia-spinel, 7 is magnesia,
8 is zircon, 9 is alumina-silicon carbide-carbon, and 10 is magnesia carbon. Aluminum lactate was used in Examples 8 and 9 of the present invention. The present invention example is
All of them had less melting loss and less slag penetration than the corresponding comparative examples. It also reduced spalling.

[Example 2] An actual machine test was conducted by using the casting material of the present invention example 2 for the bottom and the casting material of the present invention example 1 for the side wall of a 270 ton molten steel ladle. First, perma brick was installed on the bottom, then cast tuyere, porous plug, and hot water block were installed, and then the material that had been kneaded by adding 6.5% by mass of water was poured into the bottom for about 24 hours at room temperature. I was cured in.
For the side wall, first apply the perm brick, then place the core,
The material kneaded by adding 6.5% by mass of water was poured and the work was performed. After curing for about 24 hours, MgO on the slag line
-C brick was built, heated to about 1000 ° C before use, dried and preheated before use.

In the usual molten steel ladle lining, the bottom is made of the material of Comparative Example 2 and the side wall is made of Comparative Example 1. The wear rate in this case is usually 2.0 mm / ch for the bottom and 0.95 mm / ch for the side wall ( ch = charge: 1 ladle ladle is shown). On the other hand, the wear rate of the bottom invention example 2 was 1.5 mm / ch, and the wear rate of the side wall invention example 1 was 0.65 mm / ch.
The wear rate was suppressed to 0%. Also, the cracks in the refractory after use were reduced.

The actual machine test was carried out on the lining of the molten steel ladle, but the refractory material of the present invention is not limited to this, and can be widely used for the lining of equipment such as tundish, vacuum degassing furnace, converter, electric furnace, etc. You can

[0081]

INDUSTRIAL APPLICABILITY The refractory material of the present invention can exhibit excellent durability even under severe operating conditions in recent steel refining furnaces and the like. As a result, it is possible to improve the operation rate, reduce the basic unit of the refractory lining, and the number of repairs of the refractory lining.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Toshi Nakamura             1st Fujimachi, Hirohata-ku, Himeji City Nippon Steel Corporation             Inside the Hirohata Works (72) Inventor Yasuhiro Yamada             5-3 Tokai-cho, Tokai-shi Nippon Steel Corporation             Inside Nagoya Steel Works (72) Inventor Tokio Taki             5-3 Tokai-cho, Tokai-shi Nippon Steel Corporation             Inside Nagoya Steel Works (72) Inventor Shoichi Itose             1-3-1 Niihama, Arai-cho, Takasago-shi Kurosaki Harima Strain             Shiki Company Second Manufacturing Division Takasago Amorphous Factory F term (reference) 4G033 AA01 AA02 AA03 AA07 AA12                       AA14 AA17 AA21 AA24 AB10                       AB21

Claims (6)

[Claims] 1. CaO is 0.5% by mass or less, the total amount of lactic acid and glycolic acid is 0.005 to 1% by mass, and MgO is 0.1% by mass.
01 to 32 wt%, SiO ₂ is 0.05 to 50 wt%,
A refractory material characterized in that the balance comprises Al ₂ O ₃ and other unavoidable components. 2. CaO is 2% by mass or less, the total amount of lactic acid and glycolic acid is 0.005 to 1% by mass, and Al ₂ O ₃ is 0.
A refractory material characterized by comprising ₁ to 45% by mass, SiO ₂ from 0.05 to 5% by mass, and the balance being MgO and other unavoidable components. 3. CaO is 0.5% by mass or less, the total amount of lactic acid and glycolic acid is 0.005 to 1% by mass, and ZrO ₂ is 1%.
A refractory material characterized by comprising 0 to 70% by mass, SiO ₂ from 5 to 50% by mass, MgO from 0.01 to 5% by mass, and the balance being Al ₂ O ₃ and other unavoidable components. 4. CaO is 0.5 mass% or less, the total amount of lactic acid and glycolic acid is 0.005-1 mass%, and carbon is 1-4.
4 mass%, SiO ₂ 0.1-90 mass%, SiC 1
80 wt%, MgO from 0.01 to 10% by weight, refractory material, characterized in that the balance of Al ₂ O ₃ and other inevitable components. 5. CaO is 2% by mass or less, the total amount of lactic acid and glycolic acid is 0.005 to 1% by mass, and carbon is 0.5 to 3%.
0 mass%, SiO ₂ 0.05 to 20 mass%, Al ₂ O
A refractory material characterized in that ₃ is 0.1 to 15 mass% and the balance is MgO and other unavoidable components. 6. An alumina fine powder having an average particle size of 1.5 μm or less in an amount of 3 to 15% by mass, and one or more of aluminum lactate, aluminum glycolate lactate, and aluminum glycolate in a total amount of 0.01. ~ 2 mass%
And 0.01 to 3 mass% of light-burned magnesia fine powder having an iodine adsorption amount of 20 iodine mg / g or more and an average particle diameter of 1 μm or less, 6. Refractories.