JP3026640B2 - Zirconia material added basic pouring material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a highly durable casting material using a basic material used for furnace construction of various steelmaking vessels such as converters, ladles, and tundishes.

[0002]

2. Description of the Related Art Basic materials such as magnesia and dolomite have been awarded as materials constituting refractories used in steelmaking containers due to their corrosion resistance. On the other hand, from the viewpoint of furnace construction, an attempt has been made to apply an indefinite refractory construction using a pouring material or the like in order to integrally construct a vessel.

[0003] The casting of a basic material performed for the purpose of dramatically improving the slag corrosion resistance of the steelmaking container, and purifying the steel and improving the efficiency of the construction, has a disadvantage that the strength, which is a disadvantage of the construction, is small. In addition to the poor filling properties, the large thermal expansion characteristic of basic materials and the easy absorption of slag combine to inevitably cause peeling or metal intrusion due to cracks near the working surface. .

Japanese Patent Application Laid-Open No. 59-26979 discloses a means for preventing peeling of such a basic irregularly shaped article due to heating and cooling.
As can be seen in the publication, a method of mixing coarse bone with a basic material has been put to practical use. However, this method is effective at the time of heating and drying or at the beginning of operation, but since the basic material has high fire resistance and poor reactivity with slag, the slag penetrates into the material and as a result The phenomenon that structural spolling occurs was observed.

As a solution to this problem, in order to suppress slag penetration,
A first method of adding a carbon material disclosed in JP-A-59-227779 and a second method of adding a chromium component disclosed in JP-A-61-146770 have been proposed. .

[0006]

However, among the above-mentioned methods for suppressing slag permeation, the first method of adding a carbon material prevents the carbon material from being oxidized because it is difficult to form a densely formed body of irregular shape. Can not. In addition, in the second method of adding the chromium component, the volume stability of the construction body cannot be secured,
No satisfactory results have been obtained.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and it is possible to advantageously suppress slag infiltration, and to improve zirconia in which hot strength and spalling resistance can be improved. It is an object of the present invention to provide a basic pouring material added with a system material.

[0008]

Means for Solving the Problems The present inventors have studied various types of amorphous refractories using a basic material, and after intensive research, added a zirconia-based refractory material.
We succeeded in developing a material with improved hot strength and spoiling resistance in addition to the suppression of slag permeation by the basic pouring material. Further studies have found that it is more effective to add an alumina material in addition to the zirconia-based refractory material, and have completed the present invention.

That is, the present invention relates to a zirconia-based material-added basic casting material containing 3 to 20 parts by weight of a zirconia-based refractory material per 100 parts by weight of a basic refractory material. This is a zirconia-based material-added basic pouring material containing 3 to 20 parts by weight of a zirconia-based refractory material and 5 to 20 parts by weight of an alumina material with respect to 100 parts by weight of a material.

Further, the zirconia-based refractory material is preferably one or more selected from the group consisting of zirconia, alumina / zirconia, magnesia / zirconia, and calcia / zirconia.

As the basic refractory material used in the present invention, various magnesia clinkers, dolomite clinkers, calcia clinkers, magcalcia clinkers and the like are used alone or in combination. It is also possible to use these basic materials as main components and other oxide refractory materials, non-oxide refractory materials, carbon materials and the like. Further, it is also effective to add coarse aggregate of various materials having a particle size of 10 to 90 mm.

A feature of the present invention is that a zirconia-based refractory material is added to the basic refractory material. The zirconia-based refractory material contains ZrO ₂ as a main component and is at least one of zirconia, badderite, alumina / zirconia, magnesia / zirconia, calcia / zirconia, and the like. As zirconia, any of stabilizing, non-stabilizing, semi-stabilizing and the like can be used, but non-stabilizing zirconia is preferable from the effects described later. Of the above, alumina-zirconia is particularly suitable for the zirconia compound. However, since zircon generates SiO ₂ by dissociation, it is desirable to avoid zircon in view of using a basic refractory material. In the case of a zirconia compound, the ratio between zirconia and other components is preferably about 95/5 to 20/80 by weight. The amount of the zirconia-based refractory material is 3 to 20 parts by weight based on 100 parts by weight of the basic refractory material. When the amount exceeds 20 parts by weight, the volume stability of the construction body decreases, and when the amount is less than 3 parts by weight, the effect of addition is not exhibited, and neither is preferable. The zirconia-based material is desirably used for the fine powder portion.

Further, in the present invention, more favorable results can be obtained by using an alumina material in combination. Alumina materials include fused alumina, sintered alumina, sillimanite,
One or two or more of kite, andalcite, etc., and a spinel material can also be used. It is more effective to add the alumina material to the fine powder portion.
The amount of the alumina material is 5 to 20 parts by weight based on 100 parts by weight of the basic refractory material. If the amount exceeds 20 parts by weight, the reduction in corrosion resistance and volume stability decreases, and if the amount is less than 5 parts by weight, the effect of addition is not exhibited.

[0014] The casting material of the present invention contains a binder, a dispersing agent, a deflocculant, a water reducing agent and the like as appropriate in addition to the refractory material, and is completely different from the conventional casting material in blending, kneading, construction and drying. The same can be done. The work is usually carried out in an aqueous system using an alumina cement or a phosphoric acid-based binder, but can also be carried out in a non-aqueous system using a phenol resin-based binder. In the case of a water system, a cement system is more suitable for a phosphoric acid system since the construction body expands slightly. In addition, in the case of a phosphoric acid-based binder, a silica flower is added to the refractory material 1 to impart workability and strength of the construction body.
It is advisable to add 2 parts by weight.

[0015]

According to the present invention, the zirconia-based refractory material is added to the basic refractory material, so that the added zirconia changes from a monoclinic type to a tetragonal type during the heating process, and furthermore to MgO and CaO in the refractory material. And transforms into a cubic type, and finally expands in volume at that time, so that the pores of the construction body are closed, the pore diameter decreases, the air permeability decreases, preventing slag penetration and preventing the construction body heat It also leads to an improvement in inter-strength. Since the transformed zirconia reacts with MgO and CaO in the refractory material and is stabilized, when the construction body is cooled, the transformation in the reverse direction no longer occurs and the volume stability is maintained. Although there is a method in which zirconia coexists in the clinker together with magnesia, the effect due to transformation cannot be expected because zirconia is stabilized during firing of the clinker.

When the construction body comes into contact with the infiltrated slag, the zirconia component reacts with the slag and melts to increase the melting point of the slag and at the same time increase the viscosity, thereby suppressing the penetration of the slag into the construction body, and This has the effect of preventing spoiling. Further, as a result of generating microcracks in the structure when zirconia undergoes thermal transformation, the growth of cracks generated in the construction body is prevented, so that the thermal
The ring is relieved. When magnesia-zirconia or calcia-zirconia is used as the zirconia-based material, the effect of the transformation of zirconia is not seen because zirconia is stabilized, but the CaO component increases the viscosity of the slag and suppresses penetration. effective.

Addition of alumina is effective to further enhance the effect of zirconia to prevent slag penetration. Alumina also reacts with the slag to increase the viscosity to prevent penetration, so that it is more effective to use alumina in combination with zirconia. In addition, alumina reacts with magnesia to form spinel, which causes volume expansion, and thus has an effect of closing pores.
Therefore, the use of alumina zirconia is the most desirable additive. In this case, if the amount of alumina alone in alumina / zirconia is insufficient, alumina may be added separately. However, when alumina is added excessively, the volume expansion due to spinelization is too large, and the volume stability of the construction body decreases.

[0018]

EXAMPLE Water was added to a material having the composition shown in Table 1 for construction. Table 1 also shows the physical properties of the construction body after the heat treatment and the results of various tests. Zirconia is non-stabilizing,
Alumina-zirconia and calcia-zirconia used were those having a zirconia content of 40% by weight. The slag test was performed at 1650 to 1700 ° C. for 4 hours using a rotary slag erosion tester. The composition of the slag used was SiO ₂ : 18 by weight.
%, Al ₂ O ₃ : 10%, Fe ₂ O ₃ : 24%, CaO: 36
%, MgO: 6%, MnO: 3%, CaO / SiO ₂ =
2.0. The sporing resistance index was represented by an index in which rapid heat quenching between 1400 ° C. and room temperature was repeated three times, and the degree of decrease in compressive strength before and after the test was set to 100 in Comparative Example 1. In both the examples and the comparative examples, workability such as fluidity and curability was good and there was no problem.

[0019]

[Table 1]

According to Table 1, Example 1 in which a zirconia-based material was added to a basic material and Examples 2 to 5 in which alumina and zirconia were added in combination were compared with Comparative Examples 1 and 2 in which no zirconia-based material was used. Thus, any of the effects of improving hot strength, suppressing slag penetration, and improving spalling resistance are remarkably exhibited. In particular, in Examples 1, 2, and 3, it can be seen that the effect of alumina / zirconia as the zirconia-based material is remarkable.

[0021]

As described above, according to the present invention, zirconia added to a basic refractory material is transformed from a monoclinic type to a tetragonal type and further to a cubic type during a temperature rise process,
At that time, the volume expands eventually, so the pores of the construction body are closed, the pore diameter decreases, the air permeability decreases, preventing slag penetration, improving spalling resistance, and improving the hot strength of the construction body Becomes Also, by adding alumina in addition to the zirconia-based refractory material, slag penetration prevention becomes more effective.

Continued on the front page (72) Inventor Masato Nakai 1-1, Tobata-cho, Tobata-ku, Kitakyushu-shi, Fukuoka Nippon Steel Corporation Yawata Works (72) Inventor Akira Watanabe 102-12 Shiomijin 102, Okayama-shi, Okayama Prefecture 72) Inventor Hirokuni Takahashi 1799-1 Ibe, Ibe, Bizen City, Okayama Prefecture (72) Inventor Kenji Anan 55-8, Fukuoka, Osafune-cho, Oku-gun, Okayama Prefecture (56) References JP-A-3-93674 (JP, A) ( 58) Field surveyed (Int. Cl. ⁷ , DB name) C04B 35/66

Claims (3)

(57) [Claims] 1. The method according to claim 1, wherein 100 parts by weight of the basic refractory material is
A zirconia-based material-added basic casting material comprising 3 to 20 parts by weight of a zirconia-based refractory material (excluding zircon) . 2. A zirconia refractory material of 3 to 20 parts by weight and an alumina material of 5 to 20 parts by weight per 100 parts by weight of the basic refractory material.
A basic casting material added with a zirconia-based material, which is contained by weight. 3. The zirconia-based refractory material is zirconia,
One or two selected from the group consisting of alumina / zirconia, magnesia / zirconia, and calcia / zirconia
3. The method according to claim 1, wherein the number is at least one.
A zirconia-based material-added basic pouring material as described in the above.