JPH06287074A - Castable refractory containing chromium solid-solution spinel clinker - Google Patents

Abstract

PURPOSE:To provide a castable refractory, used as linings of transporting containers for molten iron such as a blast furnace spout, a torpedo car or a hot metal ladle, treating containers for molten steel such as a ladle for the molten steel, vacuum degassers, e.g. an RH degasser, a vacuum oxygen decarbonizing (VOD) container or an argon oxygen decarburizing (AOD) container and mass blocking, etc., of ladies or tundishes and excellent in corrosion and spalling resistance. CONSTITUTION:This chromium solid-solution clinker comprises 80-97wt.% chromium solid-solution spinel clinker and 3-20wt.% alumina cement and <=92wt.% alumina raw material, as necessary, may be used in combination. Furthermore, crushed grains having 10-50mm grain diameter and >=SK37 refractoriness can be used together.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a blast furnace gutter, a mixed pig iron car, a hot metal transport container such as a hot metal ladle, a molten steel ladle, a vacuum degassing device such as RH, a lining of a molten steel processing container such as VOD and AOD, and an inlet. The present invention relates to an amorphous refractory material containing a chromium solid solution spinel clinker excellent in corrosion resistance and spalling resistance used for pots, tundish mass blocks and the like.

[0002]

2. Description of the Related Art Blast furnace gutter, mixed piggy wheel, hot metal transport container such as hot metal ladle, molten steel ladle, vacuum degassing device such as RH, VOD, AO
Alumina-magnesia or magnesia-alumina, which uses high-alumina, magnesia, and spinel formation by combining alumina and magnesia as linings for molten steel processing vessels such as D, ladle, and tundish mass block Amorphous refractory such as alumina and chrome with chromium added is used. Damages of these amorphous refractories are melt loss due to hot metal, molten steel or slag, structural spalling due to slag infiltration and thermal spalling, and further improvement is required. In order to prevent the penetration of slag, it has been attempted to apply an amorphous refractory material mixed with carbon, etc., but there is a drawback that the amount of erosion increases due to the oxidation of carbon and the embrittlement of the refractory structure, which improves the durability. Has not arrived. In addition, as an amorphous refractory with improved corrosion resistance and prevention of slag penetration, MgO-Al ₂
Alumina-spinel-based materials or alumina-spinel-magnesia-based materials obtained by combining O ₃ -based spinel and magnesia with alumina are disclosed in JP-A-55-23004, JP-A-59-128271, and JP-A-60-60985, respectively. Japanese Patent Laid-Open Publication No. 64-87577.

More specifically, JP-A-55-23004 discloses that spinel clinker having a theoretical composition of MgO: Al ₂ O ₃ molar ratio of 1: 1 is 10 to 85% by weight, alumina is 5 to 30% by weight, A material composed of 10 to 25% by weight of alumina cement is disclosed in JP-A-59-128271 as MgO: Al ₂
The O ₃ molar ratio is close to the theoretical composition 0.8: 1.2 to 1.1: 0.
In the material of which the spinel of No. 9 is 50 to 95% by weight and the balance is mainly composed of alumina, JP-A-60-60985 discloses at least 60 parts by weight of spinel clinker having a theoretical composition and 10 to 35 parts by weight of alumina clinker. Part, a material consisting of 3 to less than 10 parts by weight of alumina cement is described. Further, JP-A-64-87577 discloses that MgO: Al ₂
The O ₃ molar ratio is close to the theoretical composition of 0.7: 1.3 to 1.3: 0.
No. 7, a spinel clinker of 5 to 40 wt%, an alumina clinker of 50 to 90 wt%, and an alumina cement of 3 to 25 wt% are described.

[0004]

However, these irregular shaped refractory materials are blast furnace gutters, slag line parts such as hot metal trucks, hot metal pots and ladles, RH furnaces which come into contact with molten metal or slag under high temperature and high temperature atmospheres. When used in secondary refining furnaces such as VOD, AOD, and mass blocks, the durability cannot be said to be sufficient, and the durability is improved by lining with alumina / carbon brick, magnesia / carbon brick, magnesia / chrome brick, etc. We are trying to improve it, and the present situation is that it has not been completely modified. From the viewpoint of labor saving in construction, it is strongly desired to provide an irregular refractory material having higher corrosion resistance.

Therefore, an object of the present invention is to provide a blast furnace gutter, a mixed pig iron car, a hot metal transport container such as a hot metal ladle, a molten steel ladle, a vacuum degassing device such as RH, a lining of a molten steel processing container such as VOD and AOD, and an inlet. It is intended to provide an irregular shaped refractory having excellent corrosion resistance and spalling resistance used for pots, tundish mass blocks and the like.

[0006]

[Means for Solving the Problems] The inventors of the present invention have conducted daily research on the amorphous refractory having excellent durability by improving the corrosion resistance of the irregular refractory described above, and as a result, the penetration of spinel slag MgO containing chromium as a solid solution as a spinel clinker that has both the suppression effect and the excellent heat resistance of chromium oxide and high chemical resistance to slag.
By using an Al ₂ O ₃ · Cr ₂ O ₃ -based spinel clinker, a conventional amorphous refractory that combines a conventional MgO · Al ₂ O ₃ -based spinel clinker, magnesia clinker, chromium oxide, etc. with alumina clinker By comparison, it was found that the corrosion resistance was remarkably improved, and an amorphous refractory having a corrosion resistance comparable to that of magnesia / carbon brick or magnesia / chrome brick was obtained, and the present invention was completed.

That is, the amorphous refractory material containing chromium solid solution spinel clinker according to the first aspect of the present invention contains 80 to 97% by weight of chromium solid solution spinel clinker and 3 to 20% by weight of alumina cement. Characterize.

Further, the amorphous refractory material containing chromium solid solution spinel clinker according to the second aspect of the present invention comprises 5 to 97% by weight of chromium solid solution spinel clinker, 92% by weight or less of alumina raw material and 3 to 20% by weight of alumina cement. It is characterized by containing.

The amorphous refractory material containing chromium solid solution spinel clinker according to the third aspect of the present invention is 100 parts by weight of a mixture of 80 to 97% by weight of chromium solid solution spinel clinker and 3 to 20% by weight of alumina cement. , 10 to 50 mm in size and 10 to crushed particles with fire resistance of SK37 or higher
It is characterized by adding 50 parts by weight.

Further, the amorphous refractory material containing chromium solid solution spinel clinker according to the fourth aspect of the present invention is 5 to 97% by weight of chromium solid solution spinel clinker, 92% by weight or less of alumina raw material and 3 to 20% by weight of alumina cement. 100 parts by weight of a mixture consisting of 10 to 50 mm particle size and fire resistance S
It is characterized by adding 10 to 50 parts by weight of crushed particles of K37 or more.

[0011]

The chromium solid solution spinel clinker used in the amorphous refractory of the present invention is a sintered product synthesized in a general firing facility such as a rotary kiln, a tunnel kiln or a shaft kiln, or a melting facility such as an electric furnace, It may be either an electromelted product or a combination thereof. The chemical constituent of the chromium solid solution spinel clinker is MgO 2
40 wt%, Cr ₂ O ₃ is 0.05 to 10 wt%, Cr ₂
The total amount of O ₃ and Al ₂ O ₃ has a chemical composition of 60 to 98 wt%, and MgO.Al ₂ O ₃ spinel and corundum in which chromium is solid-dissolved, or a chromium solid-solution MgO containing a small amount of periclase crystals. Any Al ₂ O ₃ spinel clinker may be used, and these can be obtained from commercial products. Here, the upper limit of MgO is set to 40% by weight because
The theoretical composition of the O.Al ₂ O ₃ spinel is MgO: Al ₂ O ₃
The weight ratio is 28.3: 71.7, and when MgO exceeds 28.3% by weight, chromium hardly dissolves in MgO and MgO precipitates as periclase crystals, which is used as an amorphous refractory. If it does, the problem of digestion due to hydration occurs. Further, the content of Cr ₂ O ₃ is 0.1.
If it is less than 05% by weight, the effect of improving the corrosion resistance is small, and if it exceeds 10% by weight, Cr ₂ O ₃ is precipitated in an undissolved state, and there is a risk of conversion to hexavalent chromium which is a harmful substance.

In the present invention, the amount of chromium solid solution spinel clinker added is 5 to 97% by weight. That is, if it is less than 5% by weight, there is no effect of improving the corrosion resistance by using the chromium solid solution spinel clinker, and if it exceeds 97% by weight, the addition amount of the alumina cement, which is the binder, becomes small and the strength is lowered. The amount of the chromium solid solution spinel clinker added when the alumina raw material is not added is preferably 80 to 97% by weight in view of the relationship with alumina cement described later.

Next, as the aluminous raw material used in the second and fourth aspects of the present invention, one or more of sintered alumina, fused alumina, bauxite, shale shale, etc. can be used. However, since an increase in the SiO ₂ component causes generation of a low melting point substance, it is preferable to use sintered alumina or fused alumina. For bauxite, bun shale, etc., it is preferable to use fine particles (0.3 mm) or more because of the problem of SiO ₂ component. The added amount is 92% by weight or less. If the amount added exceeds 92% by weight, the amount of chromium solid solution spinel clinker added and the amount of alumina cement added become insufficient, and problems of reduced corrosion resistance and reduced strength occur.

Alumina cement has hitherto been generally used as a binder for refractories. The amount added is 3 to 20% by weight. That is, if it is less than 3% by weight, the strength is insufficient and the effect as a binder is not obtained.
If it exceeds 0% by weight, the amount of CaO.MgO.Al ₂ O ₃ -based low-melting point substances produced increases, and the corrosion resistance decreases.

The relationship of the amount ratio of the above components is shown in FIGS. 1 and 2. FIG. 1 shows the mixing ratio of MgO: Al ₂ O _{3 with a} molar ratio of MgO: Al ₂ O ₃ of 3% and a solid solution of spinel clinker containing MgO: Al _{2 in} which 3% of chromium is solid-dissolved in an alumina casting material using 12% by weight of alumina cement. O ₃ mol is 1:
₃ is a graph showing the relationship between the corrosion resistance and the compounding ratio of the ordinary MgO.Al ₂ O ₃ spinel of No. 1; Further, FIG. 2 shows a mixing ratio of MgO: Al ₂ O ₃ molar ratio of chromium solid solution spinel clinker having a solid solution of 3% of chromium in an alumina casting material containing 12% by weight of alumina cement and MgO: Normal MgO · Al with Al ₂ O ₃ molar ratio of 1: 1
It is a graph showing the relationship between the mixing ratio of ₂ O ₃ spinel and slag penetration resistance.

In the third and fourth aspects of the present invention, crushed particles having a fire resistance of SK37 or more and a particle size of 10 to 50 mm are used for the purpose of improving the heat resistant spalling property by suppressing the extension of cracks. 10 to 50 parts by weight can be added to 100 parts by weight of the mixture of the above components. As the crushed particles, fused alumina crushed to 10 to 50 mm,
Alumina materials such as sintered alumina and shale shale, magnesia materials such as fused magnesia and sintered magnesia, spinel materials such as fused spinel and sintered spinel, high alumina bricks, magnesia bricks, spinel bricks, magnesia / chrome bricks One or more kinds of crushed particles of oxide-based bricks such as crushed particles of alumina-carbon brick, crushed particles of carbon-containing brick such as magnesia-carbon brick, spinel-carbon brick, and the like can be used. In order to suppress the extension of cracks and improve the heat resistant spalling property, it is preferable to use crushed particles having a larger specific surface area than spherical particles. Further, the use of crushed particles having a fire resistance of less than SK37 is not preferable because the corrosion resistance is reduced. The addition amount is the mixture 1 of the above components.
It is 10 to 50 parts by weight with respect to 00 parts by weight. That is, 1
If it is less than 0 part by weight, the effect of improving the spalling resistance by the addition is insufficient, and if it exceeds 50 parts by weight, a good construction product cannot be obtained due to an increase in the amount of added water.

Further, the amorphous solid refractory material containing chromium solid solution spinel of the present invention further includes organic fibers, metal powders such as Al, steel and stainless fibers, hardening modifiers, etc. within a range that does not impair the effects of the present invention. One or more of the above may be added.

As the method for constructing the amorphous refractory material containing chromium solid solution spinel clinker according to the present invention, casting construction, spraying construction, ramming construction, etc. can be used, and it can also be used as a material for a block lining such as a precast block. .

[0019]

EXAMPLES The amorphous refractory material containing chromium solid solution spinel clinker of the present invention will be further described with reference to the following examples. Examples Table 1 below shows chemical compositions of raw materials used in Examples and Comparative Examples.

[0020]

[Table 1]

The following Tables 2 and 3 show the raw material composition and various characteristics of the examples and comparative examples. In Tables 2 and 3, each of the amorphous refractories shown in Comparative Examples except for bricks was kneaded by adding an appropriate amount of water, and then vibration-cast into a metal frame for 24 hours at 105 ° C. After drying, it was subjected to each test shown below. (1) Line change rate after heating (1500 ° C x 3 hours): JIS-R
2555 (2) Erosion test device: Rotating drum erosion test device Sample shape: 50 × 200 × 65 mm Slag used: Converter slag (CaO / SiO ₂ = 3.65) Slag usage: 1.2 kg / cycle

[0022]

[Table 2]

[0023]

[Table 3]

Table 4 below shows the results of application in an actual furnace.

[0025]

[Table 4]

[0026]

INDUSTRIAL APPLICABILITY The amorphous solid refractory material containing chromium solid solution spinel clinker according to the first and second inventions of the present invention, by utilizing the chromium solid solution spinel clinker, suppresses the penetration of slag by spinel and the high chemistry of chromium oxide. It is a non-constant refractory material with high corrosion resistance that also has a static resistance effect, and is a material having a corrosion resistance comparable to that of magnesia-carbon bricks and magnesia-chromium bricks, which was impossible with conventional non-constant refractory materials.

The amorphous refractories according to the third and fourth inventions of the present invention have the effect of significantly improving the heat-resistant spalling property of the above-mentioned irregular refractory material, and have high corrosion resistance and high resistance. It is an amorphous refractory that has both spalling properties.

As described above, the amorphous solid refractory material containing chromium solid solution spinel clinker according to the present invention is used in the recent severe hot metal,
While exhibiting excellent durability in molten steel processing containers, ladle slag line and R
It is a material that exhibits sufficient durability even for refining vessels such as H, VOD, and AOD, and has excellent effects in labor saving in construction and reduction in the basic unit of refractory material due to indefinite shape.

[Brief description of drawings]

FIG. 1 MgO: Al in which 3% of chromium is solid-dissolved in an alumina casting material using 12% by weight of alumina cement.
Mixing ratio of chromium solid solution spinel clinker having a ₂ O ₃ molar ratio of 1: 1 and ordinary M having a MgO: Al ₂ O ₃ molar ratio of 1: 1.
is a graph showing the relationship between the mixing ratio and the corrosion resistance of the gO · Al ₂ O ₃ spinel.

FIG. 2 MgO: Al in which 3% of chromium is solid-dissolved in an alumina casting material using 12% by weight of alumina cement.
₂ O ₃ molar ratio of 1: 1 chromium solute spinel clinker proportion and MgO: Al ₂ O ₃ molar ratio of 1: 1 in ordinary compounding ratio and slag penetration resistance of MgO · Al ₂ O ₃ spinel It is a graph which shows the relationship with.

Claims (4)

[Claims] 1. Chromium solid solution spinel clinker 80-9
An amorphous refractory material containing chromium solid solution spinel clinker, which comprises 7% by weight and 3 to 20% by weight of alumina cement. 2. A chromium solid solution spinel clinker 5 to 97.
An amorphous refractory material containing chromium solid solution spinel clinker, characterized in that the content of the alumina solid material is not more than 92% by weight and the amount of alumina cement is 3 to 20% by weight. 3. Chromium solid solution spinel clinker 80-9
Chromium solid characterized by adding 10 to 50 parts by weight of crushed particles having a particle size of 10 to 50 mm and a fire resistance of SK37 or more to 100 parts by weight of a mixture consisting of 7% by weight and 3 to 20% by weight of alumina cement. Amorphous refractory containing molten spinel clinker. 4. A chromium solid solution spinel clinker 5 to 97.
1 part of crushed particles having a particle size of 10 to 50 mm and a fire resistance of SK 37 or more in 100 parts by weight of a mixture consisting of 1% by weight, 92% by weight or less of alumina raw material and 3 to 20% by weight of alumina cement.
An amorphous refractory material containing chromium solid solution spinel clinker, characterized by being added in an amount of 0 to 50 parts by weight.