JPH08151277A - Casting material for ladle - Google Patents

Abstract

PURPOSE: To obtain a casting material for a ladle that is a transferring vessel for molten steel and having excellent slag infiltration resistance and corrosion resistance as the casting material for a slag line by adding a carbonaceous raw material with a specific component. CONSTITUTION: This casting material for a ladle is composed of 80-98wt.% of a magnesia raw material and 2-20wt.% of a carbonaceous raw material, which are further mixed with 0.1-1.0wt.% of a basic aluminum lactate, 0.2-2wt.% of silica flour having particle diameters of <=5μm and 0.1-5.0wt. % of an ammonium salt of a formalin condensate with an aromatic sulfonic acid in terms of outer ratios. Preferably, the carbonaceous raw material is a mixture of carbon black with pitch and the compounding ratio of the pitch to the carbon black is one or less than one in terms of weight ratio. When the carbonaceous raw material is not the mixture of carbon black with pitch, a large amount of water is required for getting fluidity necessary to cast, and accordingly a product has a high porous ratio after dried and fails to get sufficient durability.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a casting material for a ladle which is a container for transporting molten steel, and more particularly to a casting material used for a slag line portion of a ladle.

[0002]

2. Description of the Related Art Unburned Mg is added to the slag line of a ladle.
O-C (magnesia-carbon) brick is often used, and high durability is obtained because of its excellent corrosion resistance, slag infiltration resistance, and heat resistant spalling resistance. However, in response to the shortage of brick laying workers in recent years and automation based on so-called 3K measures, amorphous refractory materials are being used as lining materials for various molten steel containers, and in ladle, alumina-spinel is used as walls and floor members. The use of quality castables is being established. Conventionally, as a slag line member for a ladle, a magnesia-containing amorphous refractory that is made of a raw material obtained by firing or melting a mixture of magnesia and zircon (ZrSiO ₄ ) and has excellent slag infiltration resistance has been reported (Japan Iron and Steel Institute). Volume, CAMP-ISIJ, Vol.5
(1992) p. 248-250). Also known is a magnesia-carbonaceous casting refractory composed of magnesia or spinel (MgAl ₂ O ₄ ) and earth-like graphite or pitch (see Japanese Patent Laid-Open No. 59-83979 and Japanese Patent Publication No. 62-20153). . Furthermore, basic aluminum lactate and silica (SiO ₂ ) are used as magnesia clinker.
An amorphous refractory material containing fine powder contained therein is also known (see JP-A-63-60168).

[0003]

However, it is difficult to say that an amorphous refractory made of a raw material obtained by firing or melting a conventional mixture of magnesia and zircon has sufficient durability as compared with MgO-C bricks. Also, magnesia-carbonaceous cast refractory consisting of magnesia or spinel and earth-like graphite or pitch is not practical because one is a non-aqueous system using phenolic resin, and the other is aqueous system, but alumina cement is used. Therefore, high corrosion resistance cannot be expected. Further, the cementless amorphous refractory obtained by adding basic aluminum lactate and fine powder containing SiO ₂ to the magnesia clinker is a non-carbon type, and improvement in durability cannot be expected due to slag infiltration. Therefore, the present invention is
An object of the present invention is to provide a pouring material for ladle which has further excellent slag infiltration resistance and corrosion resistance as a pouring material for a slag line portion.

[0004]

In order to solve the above problems, the casting material for ladle of the present invention is a magnesia raw material 8
0 to 98% by weight and 2 to 20% by weight of carbonaceous material,
Basic aluminum lactate 0.1 to 1.0% by weight,
0.2 to 2% by weight of silica flour having a particle size of 5 μm or less, ammonium salt of aromatic sulfonic acid formalin condensate 0.
1 to 5.0% by weight is added, respectively. The carbonaceous raw material is a mixture of carbon black and pitch, and it is preferable that the ratio of pitch / carbon black is ≦ 1 by weight.

[0005]

In the casting material for ladle of the present invention, when a basic material such as magnesia having excellent corrosion resistance and a carbonaceous material having excellent slag infiltration resistance are used in an aqueous system, silica flour and aromatic sulfone are used. The ammonium salt of acid formalin condensate functions to improve hydration resistance of basic raw materials and dispersibility of carbonaceous raw materials, and basic aluminum lactate gels in the coexistence of magnesia raw materials and carbonaceous raw materials. It functions as a hardening material by the action.

When the carbonaceous raw material is less than 2% by weight, it is difficult to substantially suppress slag infiltration, and improvement in durability cannot be expected, and when it exceeds 20% by weight, the working water for use as a casting material It becomes difficult to keep the amount low, resulting in a high porosity and a decrease in durability. If the amount of the basic aluminum lactate added is less than 0.1% by weight in the external ratio, the curing strength will be insufficient, and if it is more than 1.0% by weight in the external ratio, the gelation effect will be remarkable and the cured product will Generates cracks. Silica flour is indispensable as a hydration inhibitor when using a magnesia raw material in an aqueous system.
Although the details of the hydration suppressing effect of silica flour are unknown,
Selective reaction between magnesia raw material and silica flour,
In other words, it seems that the pozzolanic effect suppresses the hydration of the magnesia raw material itself. When the particle size of silica flour exceeds 5 μm, suppression of hydration of the magnesia raw material is not observed. For the same reason, if the added amount is less than 0.2% by weight, cracks due to hydration occur during drying, and if the added amount exceeds 2% by weight, the fluidity necessary for pouring is imparted. Therefore, the amount of water added increases, and the porosity of the construction body after drying becomes high, so that high durability cannot be obtained. The ammonium salt of the aromatic sulfonic acid formalin condensate compensates for the suppression of hydration of the magnesia raw material, and at the same time improves the dispersibility of the carbonaceous raw material due to the surface-active effect, resulting in a water reducing effect.
When the amount of the ammonium salt of the aromatic sulfonic acid formalin condensate added is less than 0.1% by weight in the external ratio, the water reducing effect cannot be obtained, a large amount of water is required, and the construction body after drying is Porosity becomes high, high durability cannot be obtained, and if the external ratio exceeds 5.0% by weight, a large amount of bubbles are generated in the construction body due to the surfactant effect, and the porosity of the construction body is high. As a result, high durability cannot be obtained.

When the carbonaceous raw material is other than a mixture of carbon black and pitch, for example, in the case of scaly graphite or earth-like graphite used for MgO-C bricks, a large amount of water is added in order to impart fluidity necessary for pouring. As a result, the porosity of the construction product after drying becomes high, and high durability cannot be obtained. When carbon black or pitch is used, a very small amount of working water is required. However, when only carbon black is used, a relatively dense work body can be obtained, and thus cracks are likely to occur due to the internal vapor pressure during drying. Further, when only the pitch is used, the volatile content of the pitch itself is large, so the porosity after drying becomes high, and high durability cannot be obtained. The mixing ratio of the mixture of carbon black and pitch is pitch / carbon black> 1.
If it is a weight ratio, the porosity of the construction body becomes high as in the case of using only the pitch, and high durability cannot be obtained.

[0008]

EXAMPLES Examples of the present invention will be described below together with comparative examples. Examples 1 to 3 First, various raw materials were mixed in the respective formulations shown in Table 1 to obtain casting materials. These casting materials were kneaded with water in a conventional mixer and then poured into a 40 × 40 × 160 mm mold. Then, after curing at room temperature for 24 hours, various samples were obtained by drying at a temperature of 110 ° C. for 24 hours. Each of the obtained samples was subjected to measurement of the bulk density, apparent porosity, and compressive strength, and an erosion test of dipping during slag-washing washing using an induction furnace. Also 1500 ° C
After the heat treatment at the temperature of 1, the bulk density, the apparent porosity and the dimensional change rate were measured. The measurement results and test results are also shown in Table 1.

[0009]

[Table 1]

Comparative Examples 1 to 16 First, with the respective formulations shown in Tables 2 to 4, casting materials were obtained in the same manner as in Examples 1 to 3, and after mixing with water, Examples 1 to 3 were obtained. Various samples were obtained by the same operation. In addition,
The composition using alumina cement as the hardening material did not harden even after curing at room temperature for 24 hours, so that it was dried as it was without demolding. Various samples were subjected to the same physical property measurement and erosion test as in Examples 1 to 3, and the results are shown in Tables 2 to 2.
It is also shown in 4.

[0011]

[Table 2]

[0012]

[Table 3]

[0013]

[Table 4]

From Tables 1 to 4, the products of the present invention are superior in slag infiltration resistance and corrosion resistance to the comparison products containing no carbon and the high alumina cement as the hardening material. You can see that.

[0015]

As described above, according to the casting material for ladle of the present invention, a basic raw material such as magnesia having excellent corrosion resistance and a carbonaceous raw material having excellent slag infiltration resistance are used in an aqueous system. In this case, silica flour and ammonium salt of aromatic sulfonic acid formalin condensate function to improve hydration resistance of basic raw material and dispersibility of carbonaceous raw material, and basic aluminum lactate is used as magnesia raw material and carbonaceous material. Since it functions as a hardening material by the gelling action in the coexistence of quality raw materials, it is possible to obtain the fluidity as a casting material with a small amount of construction water, and it does not contain CaO components like conventional alumina cement, Since no melting point substance is generated, the corrosion resistance and the slag infiltration resistance can be further improved.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hideo Uemoto 1st Nanto, Ogakie-cho, Kariya city, Aichi Toshiba Ceramics Co., Ltd. Kariya factory (72) Inventor, Kazuaki Matsuo 1st Nanto, Ogakie-cho, Kariya city, Aichi prefecture Toshiba Ceramix Co., Ltd. Kariya Plant (72) Inventor Noboru Nakamura 1 Nanto, Ogakie-cho, Kariya City, Aichi Prefecture CERAMIC Corp. Kariya Plant (72) Inventor Akio Kuwahara 3 Koji, Oshima, Kashima-cho, Ibaraki Prefecture Address Sumitomo Metal Industries, Ltd. Kashima Steel Works (72) Inventor Yuzo Ogiso, Hikari 3 Kashima-cho, Kashima-gun, Ibaraki Prefecture Address 3 Sumitomo Metal Industries Kashima Steel Works (72) Inventor, Masashi Ando Kashima-machi, Kashima-gun, Ibaraki Prefecture Hikari No. 3 Sumitomo Metal Industries Co., Ltd. Kashima Works

Claims (2)

[Claims] 1. A silica flower having a magnesia raw material of 80 to 98% by weight and a carbonaceous raw material of 2 to 20% by weight and an external ratio of 0.1 to 1.0% by weight of basic aluminum lactate and a particle size of 5 μm or less. A pouring material for ladles, wherein 2 to 2% by weight and 0.1 to 5.0% by weight of an ammonium salt of an aromatic sulfonic acid formalin condensate are added, respectively. 2. The carbonaceous raw material is a mixture of carbon black and pitch, wherein pitch / carbon black ≦ 1.
The pouring material for ladle according to claim 1, wherein the pouring material has a weight ratio.