JP3117180B2 - Amorphous refractory molded body and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an amorphous shaped refractory molded article (including an enforced body) having excellent hot metal resistance and spall resistance and suitable for use in a furnace bottom construction of a blast furnace for ironmaking, and a method for producing the same. About.

[0002]

2. Description of the Related Art In recent years, a blast furnace hearth structure is generally constructed by installing a carbon block as a lower layer inside a steel shell, a middle brick on the lower layer, and a chamotte brick on the upper layer. The structure is mainly.

[0003] The above-mentioned middle bricks have excellent hot metal resistance and spall resistance in order to prevent the erosion of hot metal, slag, and alkali, to insulate the heat in the furnace, and to protect the carbon blocks in the lower layers. Al ₂ O ₃ -C-Si bricks were are normally used.

In addition, Al ₂ O ₃ -C-SiC bricks and C-Si are disclosed in Japanese Patent Application Laid-Open No. 63-57706.
C bricks, further, Japanese Publication and Al ₂ O ₃ -SiO ₂ quality bricks shown in 61-122160, JP-this is brick with added SiC whiskers.

[0005] The upper brick and the middle brick are small bricks weighing about 30 to 40 kg per piece, and are piled up one by one during the blast furnace construction work, which is troublesome. Since it is hard work and takes a lot of time, the furnace construction process becomes long and the efficiency is low. In particular,
Recently, there are many problems due to the aging of the furnace construction and the shortage of skilled workers, and automation, labor saving and mechanization of the furnace are required.

As a means for solving this problem, a brick bonding block in which small bricks are combined in advance before a furnace is being built is being adopted. Since these brick adhesive blocks are apparently large bricks, they can be easily handled by using cranes and lifts during furnace construction, making furnace construction more efficient,
Enable labor saving. However, the set shape is restricted, and the cost is increased by the amount of the adhesive compared to the small brick. Further, since the number of joints does not decrease in such an adhesive block, it is not possible to expect an improvement in durability with an increase in size. In other words, mortar is usually used for joints and gaps between such bricks during furnace construction.However, mortar has a significantly poorer structure than brick, and as a result, hot metal enters the joints after the blast furnace is fired, resulting in fire resistance. Shorten the life of objects.

[0007] In view of this, it is desirable to manufacture a large-sized monolith without joints. However, large-sized bricks are difficult to manufacture due to quality or dimensional accuracy. The cost for using the firing furnace is too high to be practical.

[0008] For this reason, molded articles using irregular-shaped refractories have come to be used. In general, such a molded article made of an amorphous refractory is prepared by adding a powder material using alumina cement or the like as a binder to a mixture of a refractory raw material whose particle size has been adjusted, usually to a casting site, and adding Is added, kneaded, cast, cured, deframed, and subjected to heat treatment if necessary.

The molded article made of the amorphous refractory thus obtained has the following advantages.

[0010] Even in a large shape, uniform quality can be obtained as compared with brick, and a special molding machine and a baking furnace are not required. Therefore, the size can be easily increased, the number of joints in the hearth can be reduced, and fire resistance can be reduced. An improvement in the durability of the layer can be expected. In the case of a cast block, it is easy to install and repair a core for lifting with a lifting plug.

Since it is a cast molded body, it can be formed into a block without being restricted to a frame shape. Therefore, there is no restriction on the shape in terms of production, and there is a portion where a brick such as a gap at a furnace bottom corner can not be arranged. Special shaped bricks can be easily manufactured.

[0012] However, the amorphous refractory molded article has the following disadvantages in the production thereof, in addition to such advantages.

[0013] Since the molding pressure is lower and the amount of added moisture is larger than that of brick, the density of the molded body is low, the pore diameter is increased, the hot metal penetration resistance is reduced, and the hot strength is reduced.

Since a large amount of a binder having low heat resistance such as alumina cement is used, the corrosion resistance of the molded block,
Reduces hot properties such as volume stability and hot strength, and reduces spall resistance.

[0015] After kneading the amorphous refractory, an internal cavity is apt to be generated when molded by vibration filling when cast into a mold, and this cavity collectively develops and remains as a closed cell,
Relatively large cavities are formed on the surface and inside of the compact, thereby reducing the hot metal penetration resistance of the compact.

[0016]

SUMMARY OF THE INVENTION An object of the present invention is to provide a molded article for improving the hot strength, spall resistance, and hot metal penetration resistance of an irregular shaped refractory molded article for improving the efficiency of furnace construction. And its manufacturing method.

[0017]

The molded article according to the present invention comprises:
The high-temperature properties of the molded article are improved by using a dispersant or the like while suppressing the amount of cement added as a binder.

That is, the amorphous refractory molded article of the present invention comprises 75 to 90% by weight of Al ₂ O ₃ , 4 to 15% by weight of C, 1 to 6% by weight of metal Si, and silicic powder. of SiO ₂ 1 to 6 wt%, CaO hydraulic cements origin
Is added to a composition containing 0.5 to 2% by weight of a dispersant.
It is a cast molded product to which 0.05 to 1% by weight is added, and 1
The average pore diameter after reduction firing at a temperature of 300 to 1500 ° C. is 1 μm or less.

As the dispersing agent to be used, a dispersing agent used for a usual casting material can be used. For example, alkali metal phosphate, alkali metal carboxylate, alkali metal humate, salt such as sodium polycarboxylate, salt such as sodium alkyl sulfonate, salt such as sodium aromatic sulfonate, alkali metal silicate, Alkali metal carbonates, salts such as sodium ligninsulfonate, sodium maleic anhydride-isobutylene copolymer and ammonium salts thereof, and further, one or more kinds of substances having the same effect as those described above are obtained. You can select and use. The amount of these dispersants used is within the usual range of use, for example, 0.00 per 100 parts by weight of refractory aggregate.
It is about 5 to 1.000% by weight.

[0020] As the refractory aggregate to be used in the present moldings, corrosion resistance against the molten iron, wear resistance, Al ₂ with excellent volume stability
O ₃ is used.

[0021] As a raw material of Al ₂ O _3, as long as Al ₂ O ₃ content of 95% or more is not particularly limited, fused alumina, sintered alumina, synthetic alumina such as calcined alumina, natural corundum, Among them, natural alumina such as bauxite is mentioned, and among them, fused alumina is most desirable to satisfy the above-mentioned conditions, and the particle size is 0 mm or more and 5 mm or more.
The particle size is adjusted to two types of less than 5 mm and less than 5 mm and less than 10 mm.

In particular, it is preferable that 1 to 6% by weight of Al ₂ O _{3 be} calcined alumina of 10 μm or less.

When calcined alumina is used in combination with a dispersing agent, a deflocculant, a surfactant, etc., it has a low fluidity at the time of kneading and can be cast. It becomes strong and corrosion resistance can be improved. 1
If the amount is less than 6%, a sufficient effect cannot be obtained, and if it exceeds 6%, an oversintering phenomenon is liable to occur and the spall resistance is lowered.

The total amount of fused alumina or calcined alumina needs to be 75 to 90% by weight. If it is less than 75% by weight, the hot metal resistance is poor. Poor sport performance.

As C, natural graphite such as flaky graphite, flaky graphite and earthy graphite, artificial graphite such as artificial electrode waste, coke, carbon black, anthracite, coal powder, pitch powder, carbon brick waste and the like are used. . Among these carbons, anthracite is good because of its low solubility in hot metal, low volatile content, dense granules itself, excellent alkali resistance, and low cohesiveness. Burnt anthracite is good. Such anthracite and graphite aggregates have various particle sizes such as powder and granules, and large particles of up to about 2 mesh can be used.

As the siliceous powder, white carbon, anhydrous or hydrous amorphous silicic acid, evaporated silica, shirasu, fly ash and the like are used. In this siliceous powder, the primary particles have a particle diameter of several μm to several tens μm, and the secondary particles formed by agglomeration are also approximately 20 μm or less.

[0027] CaO is derived from hydraulic cement which is added together as a binder for refractory materials. Generally, alumina cement is used. Alumina cement is one or two equivalents of refractory alumina cement of JIS standard. Other than Ca
A high-alumina cement, a high-alumina cement super, etc., manufactured by Denki Kagaku, which has a small O content, can also be used.

The molded body can be produced by kneading under reduced pressure or molding by casting under reduced pressure vibration.

At the time of production, the types of aggregate, binder, and dispersant are determined, and are adjusted to coarse particles, medium particles, and fine particles in order to obtain a compact having a fine structure by reducing the added water during kneading.

In order to obtain a molded body having an average pore diameter of 1 μm after reduction firing at a temperature of 1300 to 1500 ° C., it is necessary to minimize the amount of water added during kneading, and be careful not to add excessive water. For example, a mixer having a good kneading effect such as a vortex mixer is used. Further, after kneading, the mixture is cast into the frame by vibratory filling while applying vibrations to the kneaded material and the frame directly or indirectly using a rod-shaped vibrator or a vibrating iron under normal pressure to deaerate the kneaded material. At this time, the kneaded material in which the amount of added water is suppressed as described above has a high viscosity and is difficult to deaerate. For this reason, when casting the kneaded material, it is difficult for the entrained air to escape, and such air gathers in the molded body to form a relatively large cavity in the molded body, thereby lowering the hot metal resistance of the molded body. Therefore, in order to prevent the formation of a cavity in the compact, if necessary, the kneaded material and the frame should be vibrated strongly during demolding to sufficiently deaerate or knead under reduced pressure or a method of casting under reduced pressure vibration. Is used to deaerate the molded body.

The average pore diameter of the molded product is 1300 to 1
After the reduction firing at 500 ° C., the compact disposed on the blast furnace hearth receives heat at the time of use and receives 130 ° C. under a reducing atmosphere.
This is because the temperature is raised to 0 to 1500 ° C. Then, at this time, the structure in the compact is densified as described above.

[0032]

[Function] With the addition of carbon, high corrosion resistance and alkali resistance against blast furnace slag, as well as improvement in spalling resistance due to volume stability, and the structure of the compact compacted by reaction with metallic silicon under a reducing atmosphere at high temperature. I do. If the amount used is less than 4% by weight, the alkali resistance and the corrosion resistance decrease.
Conversely, if the content exceeds 15% by weight, since carbon is hydrophobic, the fluidity of kneading after adding water to the powdery material of the amorphous refractory decreases, and the casting must be carried out with excess water. Therefore, a compact having a dense structure cannot be obtained, the strength is significantly reduced, and the hot metal penetration resistance is reduced.

The metallic silicon is heated and reacts with carbon under a reducing atmosphere, and self-bonds to generate β-SiC. This reaction strengthens the matrix of the molded body,
The hot strength is improved, the average pore diameter is reduced to 1 μm or less, and the hot metal penetration resistance is improved. At this time, the weight ratio at which metal silicon and carbon react is about 50 parts by weight of carbon to 100 parts by weight of metal silicon. It is desirable that the particle size of the metallic silicon be small in order to efficiently carry out the reaction, but the particle size of 1 mm or less is sufficient.
The following fine powders are even better.

Here, even if casting is performed by adding, for example, β-SiC powder, SiC whiskers, or other SiC powder raw materials to the compound without adding a predetermined amount of metallic silicon or carbon, and adjusting the particle size, The average pore diameter of the structure after reduction firing cannot be made 1 μm or less. That is, using metallic silicon and carbon as raw materials, these raw materials in the matrix react under a reducing atmosphere of 1300 to 1500 ° C. which is equal to the operating temperature of the actual furnace, and β-SiC is generated, whereby the structure becomes dense.

The reason for the reduction firing is that metal silicon and carbon react in a reducing atmosphere to form β-SiC. If oxidation firing is performed without reduction firing, metal silicon is oxidized. To silicon dioxide.

When the amount of metallic silicon is set to 1 to 6%, if it is less than 1%, a sufficient effect cannot be obtained, and if it exceeds 6%, the amount of carbon reacting with silicon powder becomes too large. As a result, metal silicon and carbon cannot be sufficiently reacted with each other, which is not industrially meaningful and also reduces spall resistance.

The reason why the average pore diameter is limited to 1 μm or less is as follows.
If the average pore diameter exceeds 1 μm, the hot metal penetrates into the compact and the compact is significantly worn.

This can be confirmed by the following equation and the calculated value.

V = A · √ (b ² r / 4) · √ (γ cos θ / η) · t v: melt penetration amount A: cross-sectional area b: apparent porosity r: pore diameter γ: melt surface Tension θ: Contact angle between the refractory and the melt t: Time η: Viscosity of the melt Therefore, by limiting the average pore diameter of the compact to 1 μm or less, the amount of hot metal entering the compact is reduced. Can be. Here, the reason for limiting the average pore diameter in the molded body is that it is difficult to reduce all the pore diameters in the molded body to 1 μm or less, and a molded body in which the average pore diameter is controlled to 1 μm or less, After trial use under the actual furnace conditions of high pressure operation, it was confirmed from the inspection results after use that there was no problem in use.

The SiO ₂ derived from the siliceous powder is used in the refractory material to densify the structure. That is, by adding a siliceous powder, the fluidity at the time of casting is improved, casting is performed with low moisture, the structure is densified, the porosity is reduced, and the hot metal resistance is improved.

A molded product containing this type of siliceous powder can be cast with low moisture by using a dispersant, a deflocculant, a surfactant and the like in combination with the calcined alumina. In addition, a dense structure can be obtained by improving the filling property, and a high-strength structure can be obtained by promoting sintering because the siliceous powder is ultrafine. 1% by weight
Above is good, and below this, sufficient effect cannot be obtained.
However, when the used amount exceeds 6% by weight, the oversintering phenomenon easily occurs, and the corrosion resistance decreases.

When the content of CaO is less than 0.5% by weight, the dry strength is reduced, and it is impossible to construct a dry molded body. Also, 2
If the content is more than 10% by weight, it reacts with the above-mentioned SiO ₂ when the refractory material is used, and anorthite (CaO.Al ₂ O ₃ .2SiO
₂ ) and Gehlenite (2CaO.Al ₂ O ₃ .Si)
O ₂ ) and other low-melting compounds are formed, lowering the heat resistance of the refractory aggregate. Alumina cement forms a hydrate when hardened, and this hydrate decomposes when the temperature rises, resulting in an intermediate strength of the refractory material. Lower.

As described above, according to the present invention, even in the case of a cast molded article, by adjusting the above composition and the casting method, 1 can be obtained.
A hot-iron-resistant brick having a mean pore diameter of 1 μm or less after reduction and firing at a temperature of 300 to 1500 ° C. can be used as a considerably shaped body. As a result, the durability in use is increased, and a large-sized molded body is made possible to facilitate the furnace construction.

Regarding the size, shape and weight of the molded body,
The size of the compact that can be adjusted in consideration of the size of the blast furnace and the size of the compact that can be adjusted in consideration of the ability of the crane and lift to handle large compacts during construction, the loading of large compacts into the hearth, and pressing work during construction. Although the size and weight are limited, compared to small bricks, the size of the compact is 0.1
About m ³ or more is necessary, and preferably about 0.2 m ³ or more can be applied.

[0045]

EXAMPLES Examples in which the present invention is applied to a molded product for a blast furnace hearth are shown below together with comparative examples.

Examples 1 to 4 Examples 1 to 3 in Table 1 show that calcined alumina, metallic silicon,
The addition amount of the siliceous powder, the hydraulic cement, and the dispersant is kept constant within a predetermined range, and the addition amount of the calcined anthracite is 4 to 15 parts, that is, the C amount is 4 to 15% by weight. And adjusted with fused alumina so that the total was 100 parts. In Example 4, the amount of metallic silicon was increased from the composition of Example 3, and the Al ₂ O ₃ component was adjusted to the lower limit to obtain a blended raw material.

The particle size of this compounded raw material is adjusted to coarse particles, medium particles, and fine particles so that dense packing can be obtained, and water is added to each powder material so as to be in a standard softness state specified in JIS R2553. After kneading, pressure-reduced vibration casting was performed at a size of 900 × 600 × 500 mm, and after curing, deframing and drying, cut out to a size of approximately 200 × 100 × 100 mm,
Reduction calcination was performed at 350 ° C. in a sheath filled with coke breeze. Thereafter, a sample was cut out in a size of 40 × 40 × 160 mm, and the quality was measured.

[0048]

[Table 1] As Comparative Example 1, the blended raw materials shown in Table 2 were mixed for 100 minutes after kneading.
After molding at a molding pressure of 0 to 1300 kg / cm ² , removing the frame, drying, and reducing and firing at 1350 ° C., 40 × 40 × 14
A sample was cut out at a size of 0 mm. Thereafter, a quality measurement was performed.

The molded articles shown in Examples 1 to 4 obtained the same or better quality as compared with the quality of the brick of Comparative Example 1.

In Comparative Examples 2 to 4 shown in Table 2, 0 parts (C = 0%), 3 parts (C = 3%) and 16 parts (C = 1
6%) and the adjusted Al ₂ O ₃ is greater than 90%,
It was less than 5%. As for the manufacturing method, a sample was manufactured in the same manner as in Examples 1 to 4, and the quality was measured.
Samples with C of 3% and 0% cracked in the spalling test, and samples with a large C of 16% had insufficient strength and could not be molded.

[0051]

[Table 2] Examples 5 and 6 In Examples 5 and 6 of Table 1, the amounts of calcined alumina, calcined anthracite, siliceous powder, hydraulic cement, and dispersant were fixed within the scope of the present invention, and metallic silicon was used. 1 copy (Si = 1
%) And 5 parts (Si = 5%), and adjusted with fused alumina so that the total becomes 100 parts. The production of the sample
The quality was measured by the same method as in Examples 1 to 4, and as a result, the quality was equal to or higher than the quality of the brick in Comparative Example 1.

In Comparative Examples 5 and 6 in Table 2, the metal silicon was 0%.
Parts and 7 parts (Si = 7%) of the additive were manufactured in the same manner as in Examples 1 to 4, and then sampled and quality was measured. was there. In the case of 7% Si, the infiltration of hot metal was not observed, but cracks occurred in the spalling test.

Examples 7 and 8 In Examples 7 and 8 shown in Table 1, the amounts of the calcined alumina, calcined anthracite, metallic silicon, siliceous powder, and the dispersant were determined.
The composition of the product is constant within the scope of the claims, and 2 parts (CaO = 0.6%) and 6 parts (CaO =
(1.8%) and adjusted with fused alumina so that the total would be 100 parts. The samples were manufactured in the same manner as in Examples 1 to 4, and the quality was measured. As a result, the quality of the bricks was equal to or higher than that of the brick of Comparative Example 1.

In Comparative Examples 7 and 8 shown in Table 2, 1 part (CaO = 0.3%) and 8 parts (CaO = 2.4) of the hydraulic cement were used.
%) Was manufactured in the same manner as in Examples 1 to 4, and the quality was measured by sampling. As a result, CaO was 0.3%.
%, The sample was not molded due to insufficient strength. When the content of CaO was as high as 2.4%, cracks were generated in the spalling test, and permeation of hot metal was observed in the hot metal permeation test. Examples 9 and 10 Examples 9 and 10 in Table 1 show calcined alumina, calcined anthracite,
The addition amounts of the metal silicon, hydraulic cement and dispersant are fixed within the scope of the present invention, and 1 part of the siliceous powder (SiO
₂ = 1%) and 5 parts (SiO ₂ = 5%), and the total is 1
It was adjusted with fused alumina so as to be 00%. The samples were manufactured in the same manner as in Examples 1 to 4, and the quality was measured. As a result, the quality of the bricks was equal to or higher than that of the brick of Comparative Example 1.

In Comparative Examples 9 and 10 in Table 2, the siliceous powder was
Parts and 7 parts after fabrication addition products of (SiO ₂ = 7%) in the same manner as in Examples 1-4, sampling and result of quality measurement, what SiO ₂ is 0%, the spalling test No cracks occurred in the test, but infiltration of hot metal was observed in the hot metal infiltration test. When the content of SiO ₂ was as high as 7%, cracks were generated in the spalling test, and infiltration of the hot metal was observed in the hot metal permeation test.

Examples 11 and 12 In Examples 11 and 12 shown in Table 1, the amounts of calcined anthracite, metallic silicon, siliceous powder, hydraulic cement and dispersant were fixed within the scope of the present invention. 1 part and 6 parts of calcined alumina were added and adjusted with fused alumina so that the total would be 100%. The samples were manufactured in the same manner as in Examples 1 to 4, and the quality was measured. As a result, the quality of the bricks was equal to or higher than that of the brick of Comparative Example 1.

On the other hand, Comparative Examples 11 and 1 shown in Table 2
2 is a calcined alumina containing 0 parts and 7 parts of additives.
After manufacturing in the same manner as above, sampling and quality measurement were performed. As a result, no cracking occurred in the spalling test for calcined alumina with 0% 0%, but penetration of hot metal was observed in the hot metal penetration test. Was done. In the case of calcined alumina as large as 7%, cracks occurred in the spalling test, and infiltration of hot metal was observed in the hot metal infiltration test.

Examples 13 and 14 Examples 13 and 14 shown in Table 1 were the same as Examples 1 to 4 except that the amount of the dispersant added in Example 1 was 0.005 part and 1 part on the outside. Quality measurement after production by
Comparative Example 1 In comparison with the quality of bricks, all of them obtained equal or higher quality.

On the other hand, Comparative Examples 13 and 1 shown in Table 2
No. 4 is an additive having 0 parts and 1.1 parts of a dispersant as in Examples 1 to 4.
As a result of quality measurement by sampling after production in the same manner as in the above, it was found that the sample with 0% dispersant had insufficient strength and could not be molded. When the dispersant content was as high as 1.1%, cracks were generated in the spalling test, and permeation of the hot metal was observed in the hot metal permeation test.

Comparative Example 15 shown in Table 3 is the same as that of Example 1
Was replaced by β-SiC generated after firing, and the quality was measured by sampling after manufacturing in the same manner as in Examples 1 to 4. As a result, no crack was generated in the spalling test. Infiltration test showed penetration of hot metal.

In Comparative Example 16 shown in Table 3, the calcined anthracite of the composition of Example 1 was replaced with β-SiC, and the quality was measured by sampling after production in the same manner as in Examples 1 to 4. As a result, no crack was generated in the spalling test as in Comparative Example 15, but permeation of the hot metal was observed in the hot metal permeation test.

Further, in Comparative Example 17 shown in Table 3, 4 parts of calcined anthracite (C
The amount was 4% by weight), replaced with 5 parts of β-SiC, manufactured in the same manner as in Examples 1 to 4, sampled, and measured for quality. As a result, permeation of the hot metal was observed in the hot metal permeation test. .

Further, Comparative Example 18 shown in Table 3
Water is added to the powdered material to the standard softness indicated by JIS R2553 in the composition of Example 1 in Table 1, and after kneading, vibration casting under a normal pressure of 900 × 600 × 500 mm is performed. After curing, de-framing and drying, about 200 × 1
After cutting into a size of 00 × 100 mm, reduction firing was performed at 1350 ° C. in a sheath filled with coke breeze. Thereafter, a sample was cut out in a size of 40 × 40 × 160 mm, and the quality was measured. In the sample thus obtained, many residual air bubbles were confirmed on the surface and inside thereof, the average pore diameter became 1 μm or more, and permeation of hot metal was recognized in the hot metal permeation test.

Further, Comparative Examples 19 to 22 shown in Table 3
The addition amount of the fused alumina, calcined alumina, metallic silicon, siliceous powder, hydraulic cement, and dispersant is fixed within the scope of the present invention, and 4 parts of calcined anthracite is used as another carbon source, that is, anthracite, pitch. , Carbon black, and coke, and blended in 4 parts each, and cast, deframed, cured, and dried in a size of 900 × 600 × 500 mm in the same manner as in Examples 1 to 4. As a result, due to the change of the carbon source, the curing strength of the molded body decreases due to an increase in the added moisture during kneading, the internal vapor pressure increases during drying, and the internal pressure in the molded body increases due to volatile components in the carbon source. Internal cracks after drying, 40 × 40
A sample could not be cut out at a size of × 160 mm, making quality measurement impossible.

[0065]

[Table 3] As described above, the reduction firing of the molded body of the present invention has been described in the case where the molded body is subjected to heat when the furnace is ignited after the molded body is built on the blast furnace hearth. Heat treatment in advance, and the furnace can be built on the blast furnace hearth. For example, after the casting is completed, the unframed and cured Al ₂ O ₃ −
After the C-Si based molded body is dried at 300 to 500 ° C.,
Reduction firing at 1300 to 1500 ° C. can be performed in advance.

When the molded article of the present invention is applied to a blast furnace, a molded article can be obtained by setting a mold frame at the bottom of the blast furnace and casting directly, instead of the molded article in advance.

The compact obtained in this manner is placed on a blast furnace hearth, and after burning, the compact receives heat, that is, is reduced and fired to densify the structure and has characteristics similar to brick.

[0068]

The following effects can be obtained by the molded article of the amorphous refractory of the present invention.

(1) Since it is possible to build a large molded body, the construction period can be shortened, and the furnace can be saved in labor.

(2) Since the number of joints is small, when hot metal comes into contact with the hot metal, melting loss due to hot metal and slag intrusion into the joints can be reduced, and the refractory layer of the blast furnace hearth, that is, the service life of the refractory becomes longer. (3) Since it is a cast molded body, there is no restriction on the shape from the viewpoint of manufacturing. In other words, specially shaped bricks that include parts where bricks can not be placed, such as gaps in the upper furnace bottom corner part of the furnace, can not be manufactured with bricks so far, or the manufacturing cost is too high, so stamps and mortar etc. However, if it is a molded article, such a special shape can be produced relatively easily.

──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Rin Nakamura 20-1 Shintomi, Futtsu-shi, Chiba Nippon Steel Corporation Technology Development Division (72) Inventor Akio Ishii 20-1 Shintomi, Futtsu-shi, Chiba New Nippon Steel Corporation (58) Investigated field (Int. Cl. ⁷ , DB name) C04B 35/00-35/22 C04B 35/622-35/636 C04B 35/66

Claims (4)

(57) [Claims] 1. An Al ₂ O ₃ content of 75 to 90% by weight and a C content of 4%.
15 wt%, the metal Si 1 to 6% by weight, and SiO ₂ 1 to 6 weight percent of the siliceous powder origin, the CaO of hydraulic cement origin composition containing 0.5 to 2 wt% It is a cast molded product to which a dispersant is added in an amount of 0.005 to 1% by weight, and has an average pore diameter of 1 μm or less after reduction firing at a temperature of 1300 to 1500 ° C. . 2. The amorphous refractory molding according to claim 1, wherein 1 to 6% by weight of Al ₂ O ₃ is calcined alumina. 3. The amorphous refractory molded product according to claim 1, wherein a part or all of the C content is calcined anthracite. 4. An Al ₂ O ₃ content of 75 to 90% by weight and a C content of 4%.
15 wt%, the metal Si 1-6% by weight, and SiO ₂ 1-6 wt% of the siliceous powder origin, composition consisting of CaO hydraulic cements origin containing 0.5-2 wt% A method for producing an amorphous refractory molded body, characterized in that raw materials to be used are kneaded under reduced pressure or cast under reduced pressure.