JPH06144939A - Basic castable refractory - Google Patents

Abstract

PURPOSE:To improve corrosion resistance by compounding the refractory aggregate containing MgO and a small amount of ZrSiO4 with the compound of Al2O3 and/or ZrO2, a phosphate glass and/or a borate silicate glass, a binder and a deflocculant. CONSTITUTION:The prescribed amount of Mg(OH)2 powder and ZrSiO4 powder are mixed and calcined, and the refractory aggregate containing 0.5-3.0wt.% ZrSiO4 and the remainder consisting essentially of MgO is produced. One-10 wt.pts. in outer of a phosphate glass and/or a borate silicate glass having 400-700 deg.C softening point, a suitable amount of the hydraulic binder such as alumina cement and the deflocculant such as sodium polyaclylate and water is added to the 100 wt.pts. of the compound consisting of 80-95% the refractory aggregate and 1-20% Al2O3 fine powder and/or ZrO2. And, 1-10 wt.pts. of the metallic fiber such as stainless steel having 10-30mm length is compounded at the part which requires the resistance to heat spalling.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a basic amorphous refractory having excellent corrosion resistance, slag infiltration resistance and spalling resistance, and more particularly to a refractory lining for refining molten steel.

[0002]

2. Description of the Related Art It has been conventionally known that a basic amorphous lining refractory mainly containing MgO has excellent corrosion resistance against molten steel and slag. Especially in the refining process of molten steel, the wear of refractory materials due to slag with high FeO concentration and high C / S is severe, the corrosion resistance to these slag is excellent, and the development of basic cast refractory materials that does not contaminate the molten steel has been developed. Is desired. However, the magnesia clinker used as an aggregate for the basic pouring material has a large coefficient of thermal expansion, and thus is weak against thermal spalls.
As a slag component such as the above easily penetrates, there is a drawback that structural spalls are also likely to occur. On the other hand, JP-A-60
In JP-A-60986, an alumina clinker and a spinel clinker are added to a magnesia clinker.
7-92581 attempts to improve the slag infiltration resistance and the structural stability by adding a graphite aggregate to the magnesia clinker, but the high corrosion resistance, which is the greatest attraction of the basic material, has been proposed. It will damage.

[0003]

The basic amorphous refractory containing MgO as a main component exhibits high corrosion resistance against high basicity slag in a molten steel refining vessel, but thermal spall or slag infiltration due to expansion. It also has the drawback that structural spalls due to For this reason, peeling damage frequently occurs in refining vessels under severe operating conditions, and the high corrosion resistance cannot be utilized. Therefore, in the present invention, while maintaining the high corrosion resistance originally possessed by the basic refractory, not only to prevent structural spall by suppressing the slag infiltration, but also a base showing a strong resistance to thermal spall. The purpose is to provide an irregularly shaped refractory material.

[0004]

The present invention provides, as the molten steel refining vessel lining material, a refractory bone containing ZrSiO ₄ in an amount of 0.5% by weight or more and less than 3.0% by weight, and the balance being mainly MgO. Material 80-99 wt% and Al ₂ O ₃ , Z
One or _two of phosphate glass and borosilicate glass are added to 100 parts by weight of a mixture containing 1 to 20% by weight of either or both of rO ₂ and 1-1.
The object is to provide an amorphous refractory containing 0 part by weight and an appropriate amount of a binder and a deflocculant.

Further, for a portion requiring a higher heat resistance spall resistance, ZrSiO ₄ is added in an amount of 0.5% by weight or more.
A blend comprising less than 0% by weight of 80% to 99% by weight of refractory aggregate containing MgO as a main component and one or both of Al ₂ O ₃ and ZrO ₂ and 1 to 20% by weight. 1 to 10 parts by weight of one or two kinds of phosphate glass and borosilicate glass is applied to 100 parts by weight, and 1 to 10 parts by weight of metal fiber is applied to the outside, and an appropriate amount of bonding is performed. The present invention provides an irregular shaped refractory material characterized by containing an agent and a deflocculant.

[0006]

The clinker used as the main aggregate in the present invention is
As described above, the content of ZrSiO ₄ is 0.5% by weight or more and less than 3.0% by weight. Powdered Mg in the starting material
ZrSiO ₄ mixed with (OH) ₂ or active MgO powder in the powder state is used as ZrO ₂ and S during clinker firing.
Dissociated into iO ₂ and ZrO ₂ and 2Mg at the periclase grain boundary
It exists as O.SiO ₂ . When ZrSiO ₄ is contained in the above range, the dissociated SiO ₂ component forms a highly viscous liquid phase with the infiltrated slag, so that the infiltration of the slag can be suppressed and the corrosion resistance is not adversely affected. Where ZrSiO ₄
If the amount of Cu is 3.0% by weight or more, the SiO ₂ component existing in the periclase grain boundaries becomes excessive, so the corrosion resistance due to the infiltrated slag decreases, and if it is less than 0.5% by weight, the infiltration of the slag cannot be suppressed. .

The basic amorphous material of the present invention comprises 80 to 99% by weight of the above refractory aggregate and 1 to 20% by weight of one or both of Al ₂ O ₃ and ZrO ₂ . The reason for adding Al ₂ O ₃ here is that during use, Al ₂ O ₃ reacts with MgO in the vicinity of the operating surface to form MgO.Al ₂ O ₃ (spinel) with good corrosion resistance in the matrix part, It is to increase the bonding force between particles and suppress the infiltration of slag. Therefore, this added Al ₂ O ₃ is more effective when added in the form of fine powder because the reaction proceeds faster.
The reason why the amount of Al ₂ O ₃ added is 1 to 20% by weight is as follows.
If it exceeds 20% by weight, the above reaction proceeds too much, the structure becomes dense, and the heat resistant spall resistance deteriorates.
This is because if the amount is less than the above, the amount of spinel produced is small and the effect of suppressing slag infiltration cannot be seen.

Next, the reason for adding ZrO ₂ is to reduce the viscosity of the slag by allowing ZrO ₂ to absorb the CaO component in the slag that has infiltrated into the refractory, thereby suppressing the infiltration. Z which is usually used as a refractory material
As rO ₂ , in addition to ZrO ₂ simple substance, CaO, MgO,
The so-called "stabilized zirconia", which is a solid solution with Y ₂ O ₃ , Al ₂ O ₃ and the like, can be mentioned. For the present invention, unstabilized ZrO ₂ , MgO-stabilized ZrO _{2 and the} like are effective, but C
With respect to aO-stabilized ZrO ₂ , since CaO has already been absorbed, no significant effect is observed.

The reason why the amount of ZrO ₂ is 1 to 20% by weight is that if the amount of ZrO ₂ exceeds 20%, the heat-resistant spalling property becomes poor and cracks are likely to occur during temperature raising and lowering, and it is less than 1%. This is because the effect of suppressing slag infiltration is hardly seen. Al ₂ O ₃ and Zr having such a function
Since O ₂ hardly reacts with each other and does not cancel each other in terms of function, it is possible to add both at the same time.

Further, the product of the present invention contains 1 to 10 parts by weight of one or two kinds of phosphate glass and borosilicate glass as an outer coat based on 100 parts by weight of the above-mentioned composition. Any of these glasses may be used as long as they have a softening point of 400 to 700 ° C. As an example, Table 1 shows the components and softening point of each one of phosphate glass and borosilicate glass.

[0011]

[Table 1]

In the temperature range in the vicinity of this, the softening glass imparts a bonding force, and in the temperature range around 1000 ° C., MgO in the fine grain portion is bonded through the liquefied glass phase. In this way, since the strength is expressed even in the middle and low temperature range where sintering between particles is unlikely to occur, the material of the present invention has high heat resistant spall resistance, while the infiltration of the slag component is suppressed by the presence of the glass phase. It also has the effect of In order to exert the effects of these glass additions, it is necessary to add 1 part by weight or more, but if it exceeds 10 parts by weight, the glass component becomes excessive and the corrosion resistance is adversely affected.

Although the above materials have sufficient durability for ordinary refining vessels, a metal fiber is added to the above materials for a portion requiring higher heat resistance spall resistance due to rapid heating and quenching. By doing
It is possible to prevent the development of large and small cracks caused by the thermal spalls or the structural spalls, and prevent damage due to the exfoliation of the material. In order to impart this anti-stripping effect, it is necessary to add at least 1 part by weight of fiber to the outside, but if it exceeds 10 parts by weight, workability during kneading will be impaired and pores after construction will be impaired. However, there is a problem that the slag infiltrates remarkably due to the increase of the rate, the collapse of the structure due to the oxidation of Fe during use, and the deterioration of the corrosion resistance.

The metal fiber used in the present invention is 1
It is made of a metal having excellent heat resistance and oxidation resistance at 000 ° C. or higher, and indicates, for example, stainless steel or nickel alloy. The shape is such that the length is 10 to 30 mm, the cross-sectional shape is circular or rectangular, and the diameter or the length of one side is about 0.2 to 3 mm.

The basic amorphous refractory material of the present invention includes alumina cement, portland cement, ρ-alumina, hydraulic binder such as light burned magnesia, and sodium hexametaphosphate, which are used for ordinary amorphous refractory materials. A deflocculant such as sodium polyacrylate or sodium tripolyphosphate is blended, and after adding water or the like to the mixture and sufficiently kneading, it is molded by pouring and used as a refractory lining for a refining vessel.

[0016]

[Examples] As examples, data obtained regarding the effect of improving the corrosion resistance and spall resistance by various additives, a compounding example of the basic amorphous refractory which is the product of the present invention, and an example of the material showing good results The results of the furnace test are shown below. Table 2
Shows the blending of various amorphous refractories obtained in the present invention.

FIG. 6 shows a conventional clinker made by adding predetermined ZrSiO ₄ to MgO as an aggregate.
FIG. 3 is a diagram showing changes in corrosion resistance and spall resistance of an amorphous refractory made by adding an appropriate amount of a binder and a deflocculant thereto.

The term "corrosion resistance index" used herein means the average of the results of immersion test for 3 hours in molten slag having a basicity C / S = 3 or 5 at a temperature level of 1550, 1600 and 1650 ° C. in a high frequency melting furnace. Is. That is, the conventional M
The gO quality amorphous refractory material A is indicated by an index comparing the amount of erosion loss of each material, and the material A is set as a reference value 100, and the larger the value, the better the corrosion resistance.

[0019]

[Table 2]

The spall resistance index of the sample was 1400.
After holding for 15 minutes in a calcination furnace at ℃, a cycle test of rapid heating and quenching in which forced out air cooling for 15 minutes was carried out, and the number of repetitions until flaking occurred was compared with that of the conventional MgO amorphous amorphous refractory A. It is shown by an index, and the larger the value is with 100 as a reference, the better the spall resistance. From this result, the optimum amount of ZrSiO ₄ added to the clinker is 0.5% by weight or more and less than 3% by weight.

FIG. 3 shows the corrosion resistance index and the spall resistance index when gradually adding fine powder Al ₂ O ₃ having an average particle size of 10 μm or less to the amorphous refractory B containing ZrSiO ₄ in the optimum range. , And the index is based on the material B as 100. From this result, the addition amount of Al ₂ O ₃ is 1
The optimum range is from 20% to 20% by weight.

FIG. 4 shows that the irregular refractory material B has a particle size of 74 μm.
The change in the corrosion resistance index and the spall resistance index when gradually adding fine particles ZrO _{2 of} m or less is shown, and the index is shown with the material B as the reference value 100. The optimum amount of ZrO ₂ added is 1% by weight or more and 20% by weight or less.

Similarly, FIG. 5 shows a comparison of the spall resistance index when 10% by weight of fine ZrO ₂ particles having various particle sizes of 74 μm or less are added to the amorphous refractory material B. Addition Z
As the rO ₂ species, unstabilized ZrO ₂ or MgO-stabilized Z
It is most effective to add rO ₂ .

FIG. 1 (A) shows that phosphate glass is added to 100 parts by weight of an amorphous refractory E containing ZrSiO ₄ , Al ₂ O ₃ and ZrO ₂ in the optimum ranges obtained from the results of FIGS. The corrosion resistance index and spall resistance index when gradually added are shown. In addition, various indices are 10 for Material E
It is set to 0. The optimum amount of phosphate glass added is 1 part by weight or more and 10 parts by weight or less.

Similarly, FIG. 1B shows the corrosion resistance index and the spall resistance index when borosilicate glass is gradually added to 100 parts by weight of the amorphous refractory material E obtained from the results of FIGS. Is shown. In addition, various indices are 10 for Material E
It is set to 0. The optimum amount of borosilicate glass added is 1 part by weight or more and 10 parts by weight or less.

FIG. 2 shows an irregularly shaped refractory material H1 according to the present invention.
The corrosion resistance index and the spall resistance index when stainless steel fibers are gradually added to 00 parts by weight are shown. The various indices are based on the material H of 100. The optimum amount of stainless fiber added is 1 part by weight or more and 10 parts by weight or less.

Based on the above results, ZrSiO ₄ -containing Mg
The O-aggregate is the main aggregate, Al ₂ O ₃ and ZrO ₂ are added thereto, and phosphoric acid, borosilicate glass, and stainless fiber are added to the basic amorphous refractory materials F to K. It was presumed that it had higher slag infiltration resistance and heat-resistant spall resistance than the basic amorphous refractory, and still maintained high corrosion resistance, so a test was conducted using it as the RH lining. The results are shown in Table 3. The wear resistance index used here is a number showing the ratio of the wear amounts of the conventional material A and the materials F to K of the present invention in percentage. The reference value is 100, and the larger the number, the higher the durability. ing.

[0028]

[Table 3]

From the above, the materials F to K of the present invention are
It was found that compared with the conventional material A, it has less wear and shows excellent durability. As described above, this material was confirmed to have high durability as a refractory for refining equipment.
It is considered that it can be sufficiently used as a refractory material for kiln furnaces other than refining equipment such as ladle and gutter.

[0030]

As described above, by adding Al ₂ O ₃ , ZrO ₂ , glass species, metal fibers, etc. to the MgO aggregate containing a small amount of ZrSiO ₄ , the lining for refining vessels having high durability can be obtained. A refractory could be invented.
By using the basic amorphous refractory which is the product of the present invention, it is possible to extend the life of the RH and other secondary refining furnaces, and not only to reduce the amount of refractory used, but also to use conventional bricks. By using it as a part, it was possible to reduce the cost of furnace construction work.

[Brief description of drawings]

FIG. 1 (A) shows changes in corrosion resistance index and spall resistance index when phosphate glass is gradually added to material E by external coating. (B): Changes in corrosion resistance index and spall resistance index when borosilicate glass is gradually added to the material E by external coating.

FIG. 2 shows changes in corrosion resistance index and spall resistance index when stainless fiber is gradually added to material H by external coating.

FIG. 3 shows changes in corrosion resistance index and spall resistance index when Al ₂ O ₃ is gradually added to the material B.

FIG. 4 shows changes in corrosion resistance index and spall resistance index when ZrO ₂ is gradually added to the material B.

FIG. 5 shows changes in spall resistance index when various ZrO ₂ was added to Material B in an amount of 10% by weight.

FIG. 6 shows changes in corrosion resistance index and spall resistance index of each clinker in which ZrSiO ₄ was gradually added to MgO.

Continuation of front page (51) Int.Cl. ⁵ Identification number Reference number within the agency FI Technical display location C04B 35/66 Q (72) Inventor Shiro Yunari Nishinosu, Oita City, Oita Pref. Nippon Steel Oita Co., Ltd. Ironworks (72) Inventor Hitoshi Nishiwaki 1-3-1 Niihama, Arai Town, Takasago City, Hyogo Prefecture Harima Ceramics Co., Ltd.

Claims (2)

[Claims] 1. ZrSiO ₄ 0.5% by weight or more and 3.0
Blend 10 containing less than 10 wt% of the refractory aggregate containing less than 80 wt% and the balance MgO as the main component, and 1 to 20 wt% of one or both of Al ₂ O ₃ and ZrO _2.
1 to 10 parts by weight of one or two kinds of phosphate glass and borosilicate glass are externally added to 0 parts by weight, and an appropriate amount of a binder and a deflocculant are blended. Basic amorphous refractory. 2. ZrSiO ₄ is 0.5% by weight or more and 3.0
A blend 10 comprising less than 80% by weight of a refractory aggregate containing less than 80% by weight and the balance being MgO as a main component, and 1 to 20% by weight of one or both of Al ₂ O ₃ and ZrO _2.
1 to 10 parts by weight of one or two kinds of phosphate glass and borosilicate glass are externally applied to 0 parts by weight, and 1 to 10 parts by weight of metal fibers are externally applied, and an appropriate amount is bonded. A basic amorphous refractory, characterized by containing an agent and a deflocculant.