KR100209064B1 - Refractory composition for forming inner-wall in furnace - Google Patents

Abstract

The present invention relates to a refractory material for forming an inner wall suitable for reinforcing adhesion with an inner wall when filling a fireproof material in a damaged part of an inner wall of a blast furnace outlet, and increasing sinterability and robustness, and increasing corrosion resistance and physical properties. SiC) 40 to 85 parts by weight, 5 to 15 parts by weight of Ai ₂ O ₃ -SiO ₂ based material, 3 to 10 parts by weight of Al ₂ O ₃ raw material, 2 to 10 parts by weight of volatile carbon-containing material, silicon nitride as a sintering aid, 5 to 15 parts by weight of one or more metal powders of silicon, aluminum and ferrosilicon, one or two of anhydrous coal tar or a thermosetting resin is 10 to 20 parts by weight of the mixed composition.

Description

Refractory composition for forming inner wall of blast furnace exit

The present invention relates to a fireproof material (hereinafter referred to as a mud material) composition for forming an inner wall of a blast furnace outlet port, and more particularly, to enhance adhesion to an inner wall of a damaged outlet port, and to facilitate the operation of filling a mud material. In addition, the present invention relates to a mud material composition suitable for increasing corrosion resistance and physical properties while having rapid sintering and robustness.

In recent years, the size of blast furnaces, the increase in output from high-temperature and high-pressure operation, the drastic reduction of coke ratio due to the injection of pulverized coal, etc. Inner wall erosion is severely progressed due to drop and drop of inner wall or chemical reaction with inner molten iron and slag components.

Therefore, the inner portion around the exit port is greatly damaged, and as shown in FIG. 1, the depth of the inner wall of the exit port is shortened.

If the depth of the exit port is shortened, high temperature and high pressure operation are impossible, and the production cannot be increased.The heat inside the furnace is moved around the exit port, and the amount of radiant heat is increased. In extreme cases, the charterers will be kicked out of the furnace and spilled.

As a countermeasure against internal wall damage, the mud material is pushed through the exit port by using a mud gun from inside the exit port during the blast furnace or during operation, so that the mud material is accumulated. It is secured.

As a method of applying such a mud material, Japanese Unexamined Patent Publication No. Hei 4-280, 878 improves the adhesion to the main components composed of alumina, bauxite, alumina spinel, silicon carbide, silicon nitride, carbon material, clay and metal powder. Novolak-type phenolic resin solution is added as a binder for caking to increase the depth of the exit port. In Japanese Patent Laid-Open No. 63-288, 972, a refractory raw material and a binder mainly composed of SiO ₂ or Al ₂ O ₃ are used. By adding carbon fiber to the finished base material, the tensile strength is increased to form a stable depth.

However, in the depth reinforcement method using the mud material, the existing blast furnace protection layer of the blast furnace method is formed at the front end of the inner wall of the furnace, or there is an existing gummer material that is embedded (that is, the mud material is filled through the exit port). If the basic furnace wall is damaged as shown in FIG. 1, the formation of the furnace wall cannot be expected as the kind of the mud material.

Therefore, although the operation of stopping the operation of the blast furnace and replacing and repairing the damaged exit port is a fundamental measure, there is a significant economic and time loss.

The present invention has been made to solve the above-mentioned conventional problems, the mud material having a composition different from that of the prior art through the chemical reaction through the latent heat in the furnace and the reaction with coke existing in the furnace, etc. The purpose of the present invention is to enhance adhesion to the inner wall, ease of work for filling the mud material, to improve corrosion resistance to the molten iron and slag, and to provide a mud material having increased physical properties.

1 is a damaged state of the inner wall of the blast furnace.

2 is an inner wall shape diagram after filling the refractory material composition according to the present invention.

* Explanation of symbols for main parts of the drawings

4: Damage to the inner wall 5: Iron bar

6: fireproof material

The present invention is 40 to 85 parts by weight of silicon carbide (SiC), 8 to 25 parts by weight of refractory raw materials, 2 to 10 parts by weight of volatile carbon-containing materials, 10 parts by weight or less of coke, 5 to 15 parts by weight of sintering aid, coal tar, phenol One or two of the resins is composed of a mud material for securing the inner wall depth of the blast furnace exit, which is a mixture of 10 to 20 parts by weight.

The reason for the numerical limitation according to the mud material composition is as follows.

Silicon carbide is in the range of 40 to 85 parts by weight.

At this time, the silicon carbide raw material used is preferably 85% or more in purity, when the purity is 85% or less, the corrosion resistance is lowered and the erosion is faster after the inner wall is formed.

When the amount of silicon carbide having the above-mentioned grade is 40 parts by weight or less, the thermal conductivity is lowered, so that the sintering of the tissues during the working time is not complete, the corrosion resistance to the slag is lowered, and when it is 85 parts by weight or more, the workability is decreased, and the relative binder And the lack of expansion raw material is inferior in hot adhesion with the inner wall, poor tissue wear.

The refractory material is composed of 5 to 15 parts by weight of Al ₂ O ₃ -SiO ₂ based material and 3 to 10 parts by weight of Al ₂ O ₃ , which is 8 to 25 parts by weight.

The Al ₂ O ₃ -SiO ₂ based raw materials are used as hot-swellable _{material, Al 2 O 3 15 ~ 60} %, SiO 2 40 ~ 85% clay, and pyrophyllite as a function of range or silica-alumina and room Lima nitro group, Kaolinite raw materials are used.

If the amount used is 5 parts by weight or less, it is not possible to impart expandability, and when used at 15 parts by weight or more, the corrosion resistance is greatly reduced.

In addition, Al ₂ O _{3 preferably} has a purity of 95% or more and uses a raw material having a particle size of 75 μm or less, and when the amount thereof is 3 parts by weight or less, the sintering property is lowered. Corrosion resistance falls.

The coke is used in an amount of 10 parts by weight or less, but the carbon content of 80% or more, and when the coke ingot is present in the furnace may not be used, but also within 10 parts by weight even under the conditions of pulverized coal operation.

If the amount is 10 parts by weight or more, the hot strength of the structure is lowered, and the wear resistance is lowered.

The volatile carbon-containing material is used in 2 to 10 parts by weight, and is composed of a material having a softening point of 100 ° C. or higher and a material of 350 ° C. or higher.

If the amount is less than 2 parts by weight, the fluidity in the mud gun is not expressed. If the amount is more than 10 parts by weight, the amount of tar is increased and the structure becomes porous during sintering and oxidized when the gas blown in operation is oxygen. Corrosion resistance falls.

The sintering agent is 5 to 15 parts by weight of the metal powder, but at least one of silicon nitride, silicon, aluminum, ferrosilicon.

If the amount is less than 5 parts by weight, rapid sintering is difficult, and high strength properties and slag resistance at hot temperatures are not obtained.

In addition, when the amount is 15 parts by weight or more, the structure of the sintered body is rather deteriorated, and the corrosion resistance is lowered, and it is present in an unreacted excess state.

In addition, when the particle size of the powder used is 44 μm or less, the sintering becomes so fast that the next work such as secondary filling and opening is impossible, so it is preferable to use the range of 60% between 44 μm and 74 μm.

Carbon content 20 to 50% of anhydrous coal tar alone or powdered resin or liquid resin of molecular weight 400 ~ 800 is used together, the amount is 10 to 20 parts by weight.

Such coal tar resin is used to express workability to be filled after being preheated by a mud gun, and serves as a carbon source capable of reacting with metal powder, which is a sintering aid, by remaining xanthan powder during firing after filling.

At this time, if the amount used is less than 10 parts by weight, the filling workability is not expressed, and if it is more than 20 parts by weight, it becomes too soft and the inner wall forming tissue becomes weak even when filled.

In the present invention, it is preferable to use an ultra-fine powder of -0.075mm in the particle size of the whole raw material according to the resultant formulation as described above within 40 to 60%, wherein the workability and The bonding force with the residual components in the furnace is reduced, and the reaction rate with the furnace wall is also reduced.

On the other hand, if the content exceeds 60%, the filling pressure decreases during filling, so that no firm structure can be obtained in the furnace, and the sintering speed is so fast that separation of the sintered layer between filling amounts may occur, As the amount of volatile increases, the porosity of the tissue increases due to gas generation during firing.

2 is a state diagram filled with the mud material of the present invention in the damaged portion of the inner wall of the exit port, the unmelted iron ore and coke layer (1), slag layer (2), molten iron layer (3) is formed in the blast furnace, The mud material is filled in the damaged part 4 of the inner wall of the exit port, and the mud material 6 is filled in the a, b, and c portions when the mud material is introduced through the iron rod 5 connected to the mud gun (not shown). do.

Since the action of the filled inner wall forming mud material is mainly composed of iron ore and coke in the furnace, in order to form a hot adhesion with the filled mud material, the thermal energy is supplied by using the latent heat of the inside of the furnace, In addition, the following reaction of the refractory material forms an inner wall structure.

As one of the reactions, when looking at the carbide bond between the refractory metal component and carbon, the blended carbon, tar, and volatile carbon compounds are volatilized to generate CO and CO ₂ gas from above 400 ° C.

In particular, when the temperature reaches 1200 ° C. or more, CO gas continuously generates β-SiC by solid-phase reaction.

The reaction scheme is as follows.

In addition, for firm coupling with the damaged inner wall,

Primarily

Secondarily

These chemical reactions enable the formation of inner wall formation in the furnace.

The following is described according to the embodiment.

As shown in Table 1, the conventional mud material (A, B) and Example (C ~ E) composition of the mud material of the present invention.

Table 2 shows the quality characteristics according to the composition.

As a result of applying the molten iron in the Korex blast furnace, whose depth was sharply lowered due to damage to the inner wall of the exit port by high-temperature operation, and using the material of Table 1 after discharging the slag, it was shown in Table 3.

In the state where the damage of the furnace wall proceeds as shown in FIG. 1, the formation of the furnace wall and the depth of the furnace were not achieved only by the filling of the existing mud material. However, after applying the present invention, the depth of the furnace body was secured to the depth of the furnace body. Also it can be seen that the return to the normal state.

Therefore, it is judged that the present invention forms a sufficient furnace wall at the damaged part of the furnace, and the furnace wall is formed as shown in FIG.

In the D material with less expansion material, the thermal expansion effect was less, and the depth of the exit port gradually decreased as the service life was decreased due to insufficient bonding between the filled mud material and the damaged inner wall.

However, if the content of the expanded material including the clay presented in the range of the composition of the present invention exceeds 15%, the initial depth is secured as much as the existing furnace body, but the damage progresses gradually due to deterioration of corrosion resistance as the use period elapses, resulting in shorter depth. Losing results were obtained.

By applying the mud material composition for forming the inner wall formed as described above to the blast furnace whose depth is sharply lowered by the inner wall damage of the exit port, it has a strong bond with the damaged inner wall in response to the reaction using the latent heat inside the blast furnace repair and Increased depth and erosion resistance ensure the normal operation of the blast furnace, allowing stable operation without disrupting production planning.

Claims (5)

40 to 85 parts by weight of silicon carbide (SiC), 5 to 15 parts by weight of Ai ₂ O ₃ -SiO ₂ based material, 3 to 10 parts by weight of Al ₂ O ₃ raw material, 2 to 10 parts by weight of volatile carbon-containing material, and sintering aid 5 to 15 parts by weight of at least one metal powder of silicon nitride, silicon, aluminum, and ferrosilicon, and 10 to 20 parts by weight of one or two of anhydrous coal tar or a thermosetting resin. Refractory composition for forming. The refractory composition for forming an inner wall of a blast furnace exit port according to claim 1, wherein coke is added in an amount of 10 parts by weight or less. The raw material according to claim 1, wherein the Ai ₂ O ₃ -SiO ₂ -based raw material is a hydrous or anhydrous silicate alumina having Al ₂ O ₂ 15 to 60%, SiO ₂ 40 to 85% grade, and clay and lead stone, silimite group, kaori A fireproof composition for forming an inner wall of a blast furnace exit port, which is characterized by being a knight group. The fire retardant composition according to claim 1, wherein the anhydrous coal tar has a carbon content of 25% or more. The refractory composition for forming an inner wall of a blast furnace outlet port according to claim 1, wherein a total of -0.075 mm of the total particle size of the composition comprises 40 to 60%.