JPH05170559A - Zrb2-c based filler for tap hole of blast furnace - Google Patents

Abstract

PURPOSE:To provide a long-life filler for a tap hole of a blast furnace. CONSTITUTION:The objective long-life filler for a tap hole of a blast furnace contains ZrB2 and carbon powder having particle diameters adjusted to <=3mm, preferably <=1mm in amounts of 15-90 pts.wt. and 10-35 pts.wt., respectively. The function of ZrB2 comprising excellent slag resistance and molten iron resistance can fully be exhibited to enable the spouting of molten iron over a long period by the balanced discharge of slag and molten iron.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ZrB ₂ -C type filler used for closing the taphole of a blast furnace.

[0002]

2. Description of the Related Art Conventionally, as a filler for a blast furnace taphole, as described in Japanese Patent Publication No. 50-39091, oxides such as pyrophyllite and alumina, and non-oxides such as silicon carbide and silicon nitride. It is usually used that carbon or the like is used as an aggregate, clay, pitch or the like is added to the aggregate, and an organic compound such as tar or resin is used as a binder.

However, this filler needs to be softened by using a relatively large amount of binder due to the capacity of blast furnace equipment such as a mud gun and an opening machine, which results in a structure as a refractory after filling. There is a constraint that the strength is not good and the strength is not so high. Therefore, in the final stage of tapping, there is a problem that the opening diameter of the tapping hole becomes large due to the disappearance of the filling, the tapping and slagging speed rapidly increase, and the tapping time becomes short and the tapping state cannot be controlled. there were.

As a means for solving the problem, a method of reducing the "open hole diameter" has been adopted, but the speed at the initial stage of tapping is too slow and the slag discharge is delayed, so that the operating trouble due to the rise of the internal pressure of the furnace is likely to occur. Therefore, the "aperture diameter" that governs the durability of the filler must be selected to be an appropriate diameter for discharging the hot metal and slag in a well-balanced manner, and the number of taps per day is almost fixed. There is.

Further, as seen in JP-B-48-79218, ZrSiO ₄ (zircon) is added and decomposed into ZrO ₂ and SiO ₂ at a high temperature (1400 ° C. or higher), and ZrO _{2 has} a fire resistance. Although some have been made to have a high durability, it is not possible to expect a significant improvement in durability due to the formation of SiO ₂ .

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a highly durable blast furnace taphole filler capable of tapping for a long time even if the taphole diameter of the blast furnace is increased. ..

[0007]

The highly durable blast furnace taphole filler of the present invention contains ZrB ₂ and carbon powder, the particle size of which is adjusted in a proportion of 15 to 90 parts by weight and 10 to 35 parts by weight, respectively. It is characterized by containing.

The particle size of ZrB ₂ used is adjusted to 3 m.
m or less, preferably 1 mm or less.

SiC, Si ₃ N ₄ or the like can be added to this filler. Since SiC, Si ₃ N _{4 and the} like have good slag resistance but poor molten pig iron resistance, the total amount is preferably 30 to 50 parts by weight, and the particle size is preferably 50 μm or less. Incidentally, Si in place of the Si ₃ N _{4 3} N ₄ Fe
It is also possible to use

[0010] It is also possible to use a ZrO ₂ having excellent corrosion resistance as well as ZrB ₂ to be used below 50 parts by weight of ZrB _2.

Refractory materials used in combination with ZrB ₂ include carbon materials usually used for taphole fillers, SiC, Si ₃ N ₄ and Si, FeSi which are non-oxides of Si. Raw materials such as sintered materials and refractory clay and wax for imparting filling properties can be used.

As the carbon raw material, anthracite, coal / petroleum coke, natural / artificial graphite, etc. can be arbitrarily selected. When the amount of use is less than 10 parts by weight with respect to 15 to 90 parts by weight of ZrB _2. However, if the amount is more than 35 parts by weight, the amount of binder increases and the structure becomes poor, and the corrosion resistance decreases. The particle size is preferably 1 mm or less, of which 50% or less is preferably contained in an amount of 50% or more.

Furthermore, if metal powder is added to this filler as a sintering agent, the strength is increased and the abrasion resistance is improved. As the metal powder, Si, Al, Al-Si alloy, Al-Mg alloy, Al-Si-Ca alloy, Al-M
A g-Ca alloy or the like can be used. For example, metallic silicon powder reacts with carbon in the formulation to form β-SiC and contributes to bonding. Further, the Al metal powder reacts with nitrogen in the compound to react with AlN or carbon to form Al ₄ C ₃ and contributes to corrosion resistance and strength development. The amount added is 1
If the amount is more than 15 parts by weight, the strength becomes too high and opening becomes difficult.

Since the front surface of the taphole is exposed to the atmosphere, there is a risk of oxidation. Although the addition of the above metal has an antioxidant effect, it is more preferable to use a boron compound such as B ₄ C together.

B ₄ C has the effect of reacting with CO to form a film of B ₂ O ₃ and preventing surface oxidation of carbon. It is sufficient to add 5 parts by weight or less to the carbon raw material. If the amount is too large, the amount of the melt is low, so that the corrosion resistance is lowered.

Further, in order to impart peeling resistance to the taphole filler at the time of opening and tapping, a fibrous substance such as Si is used.
Whiskers such as C, Si ₃ N ₄ and Al ₂ O ₃ may be added. The addition amount is preferably 1 to 3 parts by weight. If it is less than 1 part by weight, the effect of preventing peeling is small, and if it is more than 3 parts by weight, the dispersibility is deteriorated. Further, the shape of the whiskers is preferably 0.1 to 1 μm in diameter and 50 to 5000 in aspect ratio from the viewpoint of dispersibility and toughness enhancement.

Further, as the organic binder used in the filler of the present invention, commonly used coal tar or phenol resin can be applied, and those having a large amount of fixed carbon are preferable.

[0018]

The blast furnace taphole filler according to the present invention does not easily wet molten metal and is extremely stable against molten metal and slag.
It maximizes the properties of rB ₂ and its durability is significantly increased even when a relatively large amount of binder has to be used in order to use ordinary mud guns, punches and the like. If the blending ratio is less than 15 parts by weight with respect to 10 to 35 parts by weight of carbon powder, the effect is small, and if it is more than 90 parts by weight, the thermal shock resistance is impaired.

[0019]

【Example】

Example 1 Table 1 shows the relationship between strength and corrosion resistance when the amount of ZrB ₂ used was changed while the metal silicon powder was kept constant at 5 parts by weight. Although the hot strength was almost the same, the corrosion resistance was improved as the amount of ZrB ₂ used was increased, and the ZrB ₂ system showed a value 4 to 10 times that of the alumina system.

[0020]

[Table 1] Example 2 Table 2 shows the relationship between the strength and the corrosion resistance when the amount of ZrB ₂ used was changed while the metal silicon powder was kept constant at 5 parts by weight. Although the hot strength is almost the same, the corrosion resistance is improved as the amount of ZrB ₂ used is increased, and the ZrB ₂ system shows a value 4 to 9 times that of the alumina system.

[0021]

[Table 2] Example 3 In Table 3, the amount of ZrB ₂ used was 40 parts by weight of Examples 5 and 9.
The results of investigating the influence of the addition amount of metallic silicon powder as a sintered material on the strength and the corrosion resistance in 0 part by weight of Example 7 are shown. By increasing the amount of metallic silicon powder, the strength is further increased and the corrosion resistance is also improved.

Similarly, in the alumina type, the hot strength is improved by the addition of the metallic silicon powder, but the corrosion resistance is not so much improved as compared with the ZrB ₂ type.

It has been shown that the ZrB ₂ system strengthens the structure and improves the corrosion resistance by adding metallic silicon powder. The corrosion resistance was 5 to 10 times higher than that of the alumina type.

[0024]

[Table 3] Example 4 Table 4 shows the results of adding the metal Al powder, the boron compound, and the whiskers based on Example 5 in Table 2. All the additives have increased strength and good corrosion resistance.
Here, in Examples 5, 7 and 9 in which the corrosion resistance was good,
An actual furnace test was carried out in a large-scale blast furnace of 000 m ³ class. There was no problem in the filling property, and a predetermined amount of press-fitting was possible. However, since Example 9 having a high hot strength was very hard and it took time to open the hole, the hole was opened using the "O ₂ " lance. Example 5
Nos. 7 and 7 took a little longer to open the holes than the alumina type, but they could be opened by a drill.

The durability becomes longer with the addition amount of ZrB ₂ with respect to the tapping time of about 3 hours of the alumina system.
In the formulation of No. 6, the tapping time was about 6 hours, and in Example 7, 7.5.
It was time and it was possible to tap for more than twice as long. O
Example 9 with ₂ lance openings was 5 hours. Further, as a result of testing the formulations of Examples 10, 11 and 12 in Table 4 in an actual furnace, it was possible to secure a tapping time of 10 to 15% or more as compared with Example 5.

[0026]

[Table 4] As described above, it has been proved that the mud material containing ZrB ₂ as an aggregate is very excellent in corrosion resistance. The opening diameter was increased in order to facilitate initial melt discharge, but it was possible to leave the tap for a long time because of its good corrosion resistance.

[0027]

EFFECT OF THE INVENTION The blast furnace taphole filler according to the present invention fully utilizes the function of ZrB ₂ which is excellent in slag resistance and hot metal resistance, and discharges slag and hot metal in a well-balanced manner for long time tapping. to enable.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Isao Furusato 1-1, Higashihama-machi, Hachimansai-ku, Kitakyushu, Fukuoka Prefecture Kurosaki Ceramics Co., Ltd. (72) Minoru Kataoka, 7 Tsukiji, Kisarazu-shi, Chiba Kurosaki Ceramics Co., Ltd. Company Kisarazu Factory (72) Inventor Yoshihiko Uchida 7 Tsukiji, Kisarazu City, Chiba Prefecture 1 Kurosaki Ceramic Industry Co., Ltd. Kisarazu Factory (72) Inventor Takashi Matsunaga 7 Tsukiji Kisarazu, Chiba Prefecture Kurosaki Ceramic Industry Company Kisarazu Factory (72) Inventor Nakamura No. 1 Kimitsu, Kimitsu-shi, Chiba Nippon Steel Co., Ltd. Kimitsu Steel Co., Ltd. (72) Inventor Masaaki Nakayama, No. 1 Kimitsu, Kimitsu, Chiba Nippon Steel Co., Ltd. Kimitsu Steel Co., Ltd. (72 ) Inventor Shigeru Amano 1 Kimitsu, Kimitsu-shi, Chiba Nippon Steel Co., Ltd. Kimitsu Steel Co., Ltd. (72) Inventor Takeshi Iwanaga, Futtsu-shi, Chiba 20-1 Shintomi Nippon Steel Co., Ltd. Technology Development Division (72) Inventor Takayoshi Sato 1 Kimitsu, Kimitsu City, Chiba Prefecture Nippon Steel Co., Ltd. Kimitsu Works (72) Inventor Masanori Kobayashi Kimitsu City, Chiba Prefecture Kimitsu No. 1 Nippon Steel Co., Ltd. Kimitsu Steel Co., Ltd.

Claims (1)

[Claims] 1. A blast-furnace taphole filler, which comprises ZrB ₂ and C powder whose particle sizes have been adjusted in a proportion of 15 to 90 parts by weight and 10 to 35 parts by weight, respectively.