JPH06100378A - Refractory composition containing carbon compounded with boron-modified phenolic resin binder - Google Patents

Abstract

PURPOSE:To provide a carbon-containing refractory composition having excellent oxidation resistance. CONSTITUTION:A carbon-containing refractory composition is prepared by compounding a boron-modified phenolic resin as a binder to a composition containing carbon powder, one or more metals selected from Al, Mg, Ca and Si or their alloy and a refractory aggregate. The boron component to form a boron-modified phenolic resin in the carbon-containing refractory reacts with oxygen to form B2O3 and oxygen is consumed by the reaction to prevent the oxidation of the metals and alloys of Al, Mg, Ca and Si.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lining of a molten metal container such as a converter having a high secondary combustion ratio, a mixing pig car, a smelting reduction furnace,
The present invention relates to a carbon-containing refractory composition suitable for use in continuous casting equipment (nozzles, immersion nozzles, long nozzles, sliding nozzles, stoppers, etc.) and other melting furnaces for non-ferrous metals.

[0002]

2. Description of the Related Art Generally, the refractory used as an accessory for refining molten metal is excellent in spalling resistance, slag erosion resistance and wear resistance. In order to satisfy this condition, refractory materials containing carbon-containing refractory aggregates as a main component have recently become mainstream. For example, as a lining material for molten metal containers, magnesia / carbon refractory materials are used in converters, alumina / SiC / carbon refractory materials or alumina / carbon refractory materials in hot metal trucks and smelting reduction furnaces, and alumina in continuous casting equipment.・ Carbon refractories are widely used.

However, with the recent advancement of high grade steel, the refining temperature rises in converters and mixed pig irons, the secondary combustion ratio rises, smelting reduction, scrap melting, refining in ladle and tundish, etc. However, the conditions for using carbon-containing refractories are extremely severe. Under such severe conditions, the carbon-containing refractory cannot avoid the deterioration of the characteristics due to the deterioration of the refractory structure due to the oxidation of carbon.

Therefore, in order to suppress the oxidation of carbon, various metals such as Al, Mg, Ca and Si, and Si
It has been proposed to incorporate carbides such as C and B ₄ C into refractory materials. Further, it is preferable to add a metal boride compound system to JP-A-60-195061 and JP-A-64-141.
No. 74 publication.

[0005]

However, SiC, B ₄
Carbide such as C has a problem that its decomposition tends to cause deterioration of corrosion resistance and deterioration of structure, and a refractory compounded with a metal boride compound system is premised on high temperature firing, and is used as an accessory to molten metal refining equipment. There is a problem in that it is not suitable in terms of characteristics.

On the other hand, various metals such as Al, Mg, Ca and Si do not have these problems, but since they have a small effect of imparting oxidation resistance, they must be used in a large amount under strong oxidizing conditions. However, when a large amount of metal is blended in this way, properties such as spalling resistance and corrosion resistance may be impaired. Therefore, there is a limit to the amount of metal blended, and it is not possible to obtain a sufficient effect of increasing oxidation resistance. It was difficult.

The present invention has been made in view of the above points, and an object thereof is to provide a carbon-containing refractory composition excellent in oxidation resistance.

[0008]

The carbon-containing refractory composition according to the present invention comprises carbon powder, Al, Mg, and C.
It is characterized in that it contains one or more metals selected from a and Si or alloys thereof, and a refractory aggregate, and is blended with a phenol resin modified with boron as a binder.

The present invention will be described in detail below. As the carbon powder, it is possible to use any carbonaceous material such as natural graphite, artificial graphite, coke, carbon black, and mesophysical carbon, but it is preferable to use as high purity as possible. Further, as the refractory aggregate, electrofused alumina, electrofused products such as electrofused magnesia, sintered products such as sintered magnesia,
Any other material such as SiC can be used,
It is preferable that the purity and the bulk density are as high as possible.

Further, in the present invention, Al, Mg, Ca, Si
These metals are used alone or in combination of two or more, and as the metal, these alloys can also be used. The present invention is characterized by using a phenol resin modified with boron as a binder. This boron-modified phenol resin can be prepared, for example, by reacting phenol with formalin to synthesize a phenol resin, and adding boric acid to cause this reaction. The molecular structure of the boron-modified phenolic resin is generally represented by the following formula I or formula II.

[0011]

[Chemical 1]

Therefore, the above carbon powder, Al, M
The carbon-containing refractory composition according to the present invention can be prepared by blending one or more metals selected from g, Ca, Si or alloys thereof, refractory aggregates, and boron-modified phenolic resin, respectively. A carbon-containing refractory material can be obtained by kneading, molding, and curing it. Here, the blending amount of the carbon powder, the metal or alloy thereof, and the refractory aggregate is a percentage with respect to the total amount thereof, and the carbon powder is 3 wt% to 30 wt% and the metal or alloy thereof is 0.5 wt% to. The range of 7% by weight is preferable, and the balance is the refractory aggregate. In particular, if the content of the metal or its alloy is less than 0.5% by weight, the effect of increasing the oxidation resistance of the refractory cannot be sufficiently obtained by the composition of the metal or its alloy, and conversely the metal or its If the alloying amount exceeds 7% by weight, the characteristics of the refractory such as spalling resistance and corrosion resistance may be impaired, which is not preferable. In addition, the amount of boron-modified phenolic resin blended, these carbon powder, metal or alloy,
The resin content is preferably in the range of 2 parts by weight to 5 parts by weight, and the boron content in the resin is preferably in the range of 0.5% by weight to 7% by weight, based on 100 parts by weight of the total amount of the refractory aggregate. .

[0013]

The boron component internally contained in the carbon-containing refractory as a boron-modified phenol resin reacts with oxygen outside or inside the refractory to form B ₂ O ₃ , and consumes oxygen to generate Al, Mg, Ca, Si. It is possible to prevent oxidation of the metal or alloy and improve the oxidation resistance of the refractory. Especially when the refractory aggregate is MgO, B ₂ O ₃ is 2MgO.B
To form a highly viscous products such as ₂ O ₃ or 3MgO · B ₂ O _3, and if the refractory aggregate is Al ₂ O _3, B ₂ O ₃ is as 9Al ₂ O ₃ · 2B ₂ O ₃ It is possible to form a highly viscous product, coat other raw materials containing carbon to shield it from oxygen, and further improve the oxidation resistance.

[0014]

EXAMPLES The present invention will now be illustrated by examples. -Magnesia-Carbon Refractory as Lining Material for Converter- (Example 1) 940 parts by weight of phenol, 37 in a reaction vessel
% Formalin (450 parts by weight) and boric acid (310 parts by weight) were added, the mixture was refluxed for about 60 minutes, reacted for 180 minutes, and then heated to 200 ° C. for dehydration. The resulting boron-modified phenolic resin (I) has a softening point of 110.
C., the boron content was 4.2% by weight.

Then, as the refractory aggregate, electromelted magnesia and sintered magnesia are used together, and natural graphite having a purity of 98% is used. Further, Al is used as a metal and A is used as a metal alloy.
Each of the 1-Mg alloys was used, and these were put into a Simpson mixer in the composition shown in Table 1. On the other hand, the above boron-modified phenol resin (I) was added to diethylene glycol at 60: 4.
It was dissolved at a weight ratio of 0 to adjust the viscosity at 25 ° C. to 250 poise, and this was used as a binder for the formulation shown in Table 1 (Table 1
Is the resin content), and 10% by weight of hexamethylenetetramine as a curing agent is added as a curing agent to the Simpson mixer, and these are kneaded for 60 minutes to prepare a carbon-containing refractory composition. .

After the composition was filled in a mold, it was press-molded 20 times with a vacuum friction press to form a molded body in advance.
After drying for 24 hours in a dryer set at 0 ° C., it was placed in another shuttle pot and heat-cured at 250 ° C. for 10 hours. Test pieces were cut out from the carbon-containing refractory material thus obtained, and various physical properties were measured. The results are shown in Table 1. In addition, in Table 1, "the thickness of the decarburized layer (*
The test "1)" was carried out by measuring the thickness of the decarburized portion after the test piece was heat-treated at 1400 ° C under atmospheric pressure for 3 hours.
The larger the degree of decarburization, the poorer the oxidation resistance can be evaluated. Also, “Ratio of strength reduction after heat treatment (* 2)”
The test was carried out by subjecting the test piece to heat treatment at 600 ° C. for 2 hours and measuring the difference in normal temperature bending strength before and after the test, and the rate of decrease was displayed. The larger the decrease rate, the lower the oxidation resistance and the strength of the structure can be evaluated.

Comparative Example 1 Phenol 940 was placed in a reaction vessel.
Parts by weight, 689 parts by weight of 37% formalin and 9.4 parts by weight of oxalic acid were added, the temperature was raised for about 60 minutes, and the mixture was reacted for 180 minutes under reflux. Next, by heating to 200 ° C. and performing dehydration, a solid phenol resin having a softening point of 97 ° C. was obtained. This phenol resin was dissolved in diethylene glycol in a weight ratio of 60:40 to adjust the viscosity at 25 ° C. to 150 poise, and this was blended in the same manner as in Example 1 and hexamethylenetetramine was added to the resin in a weight percentage of 10%. A carbon-containing refractory composition having the composition shown in Table 2 was prepared by compounding. Then, this carbon-containing refractory composition was molded, dried and cured in the same manner as in Example 1 to prepare a carbon-containing refractory, and various physical properties were measured in the same manner as in Example 1. The results are shown in Table 2.

[0018]

[Table 1]

[0019]

[Table 2]

(Example 2) The softening point was 103 in the same manner as in Example 1 except that the addition amount of boric acid was changed to 100 parts by weight.
A boron-modified phenol resin (II) having a boron content of 1.0% by weight was prepared. Thereafter, using this boron-modified phenolic resin (II) as a binder, a carbon-containing refractory composition having the composition shown in Table 3 was prepared in the same manner as in Example 1. Then, this carbon-containing refractory composition was molded, dried and cured in the same manner as in Example 1 to prepare a carbon-containing refractory, and various physical properties were measured in the same manner as in Example 1. The results are shown in Table 3.

[0021]

[Table 3]

-Alumina.S as a lining material for hot metal cars
iC / Carbon Refractory- (Example 3) Fused alumina or SiC was used as the refractory aggregate, Al and Si were used as the metals, and otherwise boron-modified phenol resin (I ) Was added as a binder to prepare a carbon-containing refractory composition having the composition shown in Table 4. Then, this carbon-containing refractory composition was molded, dried and cured in the same manner as in Example 1 to prepare a carbon-containing refractory, and various physical properties were measured in the same manner as in Example 1. The results are shown in Table 4.

Comparative Example 2 A carbon-containing refractory composition having the composition shown in Table 5 was prepared in the same manner as in Example 3 except that the phenol resin prepared in Comparative Example 1 was used as a binder. Then, this carbon-containing refractory composition was molded, dried and cured in the same manner as in Example 1 to prepare a carbon-containing refractory, and various physical properties were measured in the same manner as in Example 1. The results are shown in Table 5.

[0024]

[Table 4]

[0025]

[Table 5]

(Example 4) A carbon-containing refractory composition having the composition shown in Table 6 was prepared in the same manner as in Example 3 except that the boron-modified phenolic resin (II) prepared in Example 2 was used as a binder. Then, this carbon-containing refractory composition was molded, dried and cured in the same manner as in Example 1 to prepare a carbon-containing refractory, and various physical properties were measured in the same manner as in Example 1. The results are shown in Table 6.

[0027]

[Table 6]

-Refractory for Alumina-Carbon Immersion Nozzle Used in Continuous Casting Facility- (Example 5) Use of fused alumina, sintered alumina, fused silica as a refractory aggregate and Si as a metal In the same manner as in Example 1 except for the above, the boron-modified phenolic resin (I) was added as a binder to prepare a carbon-containing refractory composition having the composition shown in Table 7. Then, this carbon-containing refractory composition was molded, dried and cured in the same manner as in Example 1 to prepare a carbon-containing refractory, and various physical properties were measured in the same manner as in Example 1. The results are shown in Table 7.

Comparative Example 2 A carbon-containing refractory composition having the composition shown in Table 8 was prepared in the same manner as in Example 5 except that the phenol resin prepared in Comparative Example 1 was used as a binder. Then, this carbon-containing refractory composition was molded, dried and cured in the same manner as in Example 1 to prepare a carbon-containing refractory, and various physical properties were measured in the same manner as in Example 1. The results are shown in Table 8.

[0030]

[Table 7]

[0031]

[Table 8]

Example 6 A carbon-containing refractory composition having the composition shown in Table 9 was prepared in the same manner as in Example 5 except that the boron-modified phenolic resin (II) prepared in Example 2 was used as a binder. Then, this carbon-containing refractory composition was molded, dried and cured in the same manner as in Example 1 to prepare a carbon-containing refractory, and various physical properties were measured in the same manner as in Example 1. The results are shown in Table 9.

[0033]

[Table 9]

As can be seen from the above tables, each of the examples in which the boron-modified phenolic resin was used as the binder in the same metal composition was compared with the comparative example in which the phenolic resin was used as the binder. It is confirmed that the decarburized layer has a smaller thickness than that of the above, and the strength reduction rate after the heat treatment is smaller, and the oxidation resistance is improved.

[0035]

As described above, the present invention can be used as a binder.
Since it contains a phenol resin modified with boron,
As a boron-modified phenolic resin in carbon-containing refractories
Boron component that is supposed to be internal is external or fire resistant
B reacts with oxygen inside the object₂O ₃And consumes oxygen
That Al, Mg, Ca, Si metals and alloys are oxidized.
Can also prevent the oxidation of refractory materials
Of.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Reference number within the agency FI Technical indication location C08L 61/14 LMS 8215-4J (72) Inventor Kazuhiko Kawasaki 2-5, Kumasai, Hachimansai-ku, Kitakyushu, Fukuoka −47 (72) Inventor Toshihiro Suruga 2-2 Funamachi, Hachimansai Ward, Kitakyushu City, Fukuoka Prefecture

Claims (1)

[Claims] 1. Carbon powder and Al, Mg, Ca, S
A carbon-containing refractory composition comprising one or more metals selected from i or their alloys and a refractory aggregate, and blending a boron-modified phenol resin as a binder.