JP3590474B2 - Shrinkable ramming material for blast furnace and lining structure using the same - Google Patents

Description

表１において、本発明における沸点の異なる溶剤によるフェノール樹脂を使用したラミング材の実施例１〜９は、いずれも、１００°Ｃから４５０°Ｃへの温度上昇に伴い可縮率の上昇が確認された。また、この温度域での熱伝導率はいずれも≧２０Ｗ／ｍ・°Ｃであり、さらに、スタンピングによる作業性についても問題はなかった。
【００４５】
【表２】

表２において、比較例１は、実施例１で用いたフェノール樹脂Ａを使用したが、液量が少なすぎてスタンピング不能となりサンプルの作成ができなかった。
【００４６】
比較例２は、実施例１で用いたフェノール樹脂Ａを多量に使用したため、液量が多すぎて充填不足を招いたためか、熱伝導率が低下した。
【００４７】
比較例３は、液量は規定内であったが、黒鉛原料が少ないため熱伝導率が低下した。
【００４８】
比較例４〜７はフェノール樹脂の性状が不良であるため、温度上昇に伴う可縮率の上昇が十分でなく、また、熱伝導率も１００〜４５０°Ｃの温度域で＜２０Ｗ／ｍ・°Ｃとなった。
【００４９】
次に、従来のラミング材に代わる本発明のラミング材により施工した高炉のライニング構造を図によって説明する。
【００５０】
図１は、本発明の高炉用可縮性ラミング材を用いた高炉側壁及び炉底部部分の縦断面図であり、炉外側から鉄皮１、ステーブ２、ラミング材３、そしてカーボンれんが４の順に内張りされている。
【００５１】
ラミング材３に本発明の可縮性ラミング材を使用することにより、カーボンれんが４の熱膨張による熱応力が発生してセリ出す力、即ちラミング材３への圧縮応力を吸収し割れの原因がなくなり、また、熱伝導性も良いためステーブ２による冷却効果も上がり鉄皮１の損傷も防ぐことができる。
【００５２】
図１において５はカーボン保護リングれんが、６は本発明が適用できるラミング材によるスタンプ代、７は保護れんがを示す。
【００５３】
本実施例の他に図示しないが、鉄皮１、ラミング材３、カーボンれんが４の順に配設した内張り構造もある。この場合においてもカーボンれんが４の熱応力を緩和し、高炉の長期安定操業を図ることができる。なお、冷却方法については、鉄皮１の外側に水冷ジャケットが配設されている。
【００５４】
【発明の効果】
（１） 本発明の可縮性ラミング材とこのラミング材を使用したライニング構造は、高炉の長期操業時における、炉底や炉壁部のカーボンれんがの約６０〜４５０°Ｃで発生する熱膨張による熱応力を、ラミング材の可縮により連続して吸収緩和することが可能となり、カーボンれんがのセリ割れ、ステーブまたは鉄皮の熱応力による変形を防止する。
【００５５】
（２） 本発明の可縮性ラミング材は、高い熱伝導性を持つため、カーボンれんが背面からの奪熱によってカーボンれんがの温度を低下させることができ、その結果、カーボンれんがの熱膨張を抑制し、高炉の高寿命化に寄与する。
【図面の簡単な説明】
【図１】本発明の高炉用可縮性ラミング材を用いた高炉炉壁及び炉底部分の縦断面図である。
【符号の説明】
１ 鉄皮
２ ステーブ
３ ラミング材
４ カーボンれんが
５ カーボン保護リングれんが
６ ラミング材のスタンプ代
７ 保護れんが[0001]
TECHNICAL FIELD OF THE INVENTION
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ramming material used for relaxing thermal stress of a carbon brick on a furnace bottom and a furnace wall during a long-term operation of a blast furnace, and a lining structure using the same.
[0002]
[Prior art]
Generally, the furnace bottom or side wall of the blast furnace is cooled with a stave or the like from the outside to protect the lining brick from cooling.As a thermal expansion allowance of the brick, a lining carbon brick and a stave or steel shell outside the furnace are used. As described in JP-A-53-11106 and JP-A-58-1006, a ramming (stamp) material of carbon or silicon carbide having thermal conductivity is used. ing.
[0003]
In recent years, the life of a blast furnace is 10 to 15 years, and during this long-term use, the pool is also eroded, so that, for example, heat is easily transmitted to carbon bricks disposed at the bottom of the furnace. As the operation continues, the temperature of the carbon brick gradually rises. As a result, even when the carbon brick is cooled from the outside of the furnace, its back surface temperature rises to about 100 to 450 ° C., and thermal stress is generated by the thermal expansion of the carbon brick itself, which is a cause of cracking due to swelling. Cause. That is, compressive stress acts on the ramming material cast on the back surface of the carbon brick.
[0004]
At present, as the ramming material, there is a ramming material containing a non-aqueous binder such as tar pitch, for example, in order to prevent a reduction in corrosion resistance due to steam oxidation of graphite and carbon brick.
[0005]
[Problems to be solved by the invention]
When tar pitch is used as the ramming material, the ramming material softens once in a temperature range of about 50 to 150 ° C, but gradually solidifies as the temperature rises to about 450 ° C. As the temperature rises, the deformability for relaxing the thermal stress of the carbon brick decreases.
[0006]
Further, when the temperature reaches about 200 ° C. or more, a relatively large cavity is formed in the construction body after the gas evaporates from the ramming material, and the thermal conductivity of the ramming material decreases. In addition, tar pitch itself contains harmful substances such as benzopyrene, which is not preferable in terms of environment at the time of production.
[0007]
As described above, the ramming material containing a non-aqueous binder such as tar pitch can reduce the thermal stress of carbon brick during long-term operation of a blast furnace even if the thermal conductivity is high, thereby achieving long-term stable operation. Was not enough.
[0008]
Therefore, the present invention provides a method for continuously reducing the thermal stress generated in the temperature range of 60 to 450 ° C. of the carbon brick on the furnace bottom and the furnace wall during long-term operation of the blast furnace, with the shrinkability used for continuous absorption and relaxation. It is intended to provide a ramming material and a lining structure having high thermal conductivity.
[0009]
[Means for Solving the Problems]
The shrinkable ramming material for a blast furnace according to the present invention has a boiling point different from that of an aggregate containing a graphite raw material or one or more refractory raw materials having a boiling point of not more than 10% by weight and the balance being a graphite raw material. A mixture in which 10 to 30% by weight of a shrinkable agent comprising at least one kind of solvent and a phenol resin is mixed, wherein voids are formed in a temperature rise process of 60 to 450 ° C., and a heat conductivity is 20 W / m 2 It is characterized by the fact that the temperature is at least ℃, and it is installed at the part in contact with the carbon brick of the blast furnace.
[0010]
Further, the shrinkable ramming material for a blast furnace according to the present invention is disposed in a portion in contact with the carbon brick, such as between a carbon brick and an iron shell, between a carbon brick and a stave, and in an expansion allowance portion of a carbon brick at a furnace bottom. To form a blast furnace lining structure.
[0011]
The blast furnace is said to perform a high-temperature continuous operation in which the maximum temperature in the furnace rises to 2000 ° C. or higher, so that the temperature of the lined carbon brick also rises to about 1600 ° C. Therefore, even if the carbon brick is a material having a low thermal expansion, an internal stress is generated due to the thermal expansion. Therefore, the shrinkable ramming material for a blast furnace of the present invention is characterized in that the carbon brick has a low thermal expansion property, and fully utilizes the property of high heat conductivity capable of dissipating heat, so that the carbon brick can be placed between the carbon brick and the steel bar or stave. In the area of contact with the carbon brick and the expansion allowance of the carbon brick at the bottom of the furnace, the same thermal conductivity as the carbon brick enhances the cooling effect of the carbon brick, and also functions as a cushioning material that absorbs the thermal expansion of the carbon brick .
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
The shrinkable ramming material for a blast furnace of the present invention uses a graphite material having a high thermal conductivity and a phenol resin having a high residual carbon ratio in combination with a plurality of solvents having different boiling points to provide a highly heat-conductive and continuously heatable ramming material. Express shrinkage.
[0013]
Phenol resins added to graphite are roughly classified into solid, powder, and liquid forms. Among them, solid or powdered phenol resin alone is heated and softened temporarily, but its deformability is small, and it does not reach the point where it absorbs and absorbs the thermal stress caused by the thermal expansion of carbon brick during operation of the actual furnace. .
[0014]
Further, a solvent is usually used for the liquid phenol resin. When this solvent receives heat, it evaporates little by little. For example, if its boiling point is lower than about 200 ° C., a void is formed in the construction body during the temperature rise to about 200 ° C. Although stress can be absorbed and relieved, formation of new voids in the ramming material is reduced in a temperature range of about 200 ° C. or more, and as a result, shrinkability is obtained in about 200 ° C. or more. It becomes difficult. In order to compensate for this, it is conceivable to add a large amount of these solvents, but as the solvent evaporates, very large voids are formed in the construction body, resulting in a decrease in thermal conductivity. Therefore, when the solvents having different boiling points are combined in a temperature range of less than about 60 to 250 ° C. and a temperature range of about 250 to 450 ° C., the time from the start to the end of the evaporation of the solvent overlaps with each solvent. Since it is continued, the thermal expansion of the carbon brick accompanying the temperature rise is continuously absorbed.
[0015]
Regarding the shrinkage rate, it is thought that shrinkage of about 10% or more is necessary after curing due to the recent increase in size of the blast furnace. However, as in the present invention, the shrinkage temperature is about 60 to 450 ° C. As it rises, it needs to be raised gradually.
[0016]
As the refractory aggregate used in the present invention, high thermal conductivity is required for the ramming material, so that the graphite raw material is used as a main aggregate exceeding 90% by weight. The reason for using a large amount of graphite raw material is to enhance the cooling effect of the carbon brick. Generally, the higher the thermal conductivity, the more desirable, and at least the same as the thermal conductivity of the recently used carbon brick. This is because the temperature is set to 20 W / m · ° C. or more. This is to release the heat inside the furnace as much as possible outside the furnace.However, if the thermal conductivity of the ramming material filled between the staves or the iron shell is lower than that of the carbon brick, the cooling capacity of the carbon brick decreases. It is. In addition, the function as a cushioning material mainly having a low thermal expansion property also decreases.
[0017]
As the graphite raw material, in addition to natural graphite such as flaky graphite, flaky graphite, earthy graphite and the like, artificial graphite such as graphite electrode scrap is used in the form of granules or powder.
[0018]
Aggregates other than graphite raw materials include charcoal, coke, calcined anthracite, pitch powder, carbonaceous materials such as carbon black, carbides such as silicon carbide, aluminum carbide and zirconium carbide, zirconium nitride, silicon nitride, aluminum nitride and silicon nitride iron. , Such as silicon nitride, boron nitride, etc., silicides such as silicon and ferrosilicon, borides such as boron carbide, and other materials containing oxides, such as silica, silica sand, fused silica, hydrated amorphous silica, anhydrous amorphous silica Etc., alumina such as mullite, bauxite, ban shale, sillimanite, kyanite, sintered alumina, fused alumina, calcined alumina, etc., and alumina such as rhoite, chamotte, pottery stone, clay, kaolin, bentonite etc. -Refractory raw materials such as siliceous material, zircon and zirconia can be selected and used alone or in combination of two or more.
[0019]
These refractory raw materials can be used within 10% by weight due to the particle size distribution and plasticity of the ramming material, but if it is more than this, the thermal conductivity will be lower than 20 W / m · ° C, and the characteristics of graphite will be poor. Certain high thermal conductivity cannot be utilized.
[0020]
In the present invention, as a shrinkable agent, 10 to 30% by weight of a shrinkable agent comprising two or more solvents having different boiling points and a phenol resin is used. If the amount of the shrinkable agent is less than 10% by weight, the amount of liquid in the ramming material is insufficient, so that the workability at the time of stamping is remarkably reduced, and insufficient filling is liable to be caused. Is generated, and on the contrary, insufficient filling is apt to occur, and the workability is reduced.
[0021]
Solvents used for phenolic resins are used in combination on the premise that no chemical reaction occurs between the solvents.However, the performance of the carbon brick, such as strength and corrosion resistance, must not be reduced. Those that cause trouble are not preferred.
[0022]
When a solution is made by dissolving another solvent having a high boiling point in one solvent, the boiling point of the mixed solvent is generally higher than that of the pure starting solvent. By continuously evaporating these mixed solvents in a temperature range of about 60 to 450 ° C., voids can be continuously generated in the structure of the ramming material during the process of increasing the temperature.
[0023]
The need to continuously have voids in the structure of the ramming material in a temperature range of about 60 to 450 ° C. is due to a material design having voids at a temperature lower than about 60 ° C., which is the lower limit of this temperature range. This is because most of the solvent evaporates during the period from the application at normal temperature to the heating to about 60 ° C. In the temperature range up to about 60 ° C., the number of air bubbles contained in the tissue in the ramming material increases, and it is not practically meaningful to cause a decrease in thermal conductivity. In many cases, the substance itself poses a danger in handling. Even if the material is designed so as to have voids in the amorphous refractory structure at a temperature higher than the upper limit of about 450 ° C., at or above this temperature, the thermal stress of the carbon brick is rather higher than the yield point of iron. Deformation of the steel is more problematic.
[0024]
Examples of phenols used as a raw material of the phenolic resin used in the present invention include phenol, orthocresol, metacresol, paracresol, xylenol, ethylphenol, propylephenol, butylphenol, octiphenol, noniphenol, phenylphenol and cumyl. There are phenols such as phenol, catechol, resorcinol, hydroquinone and bisphenol A, and these can be used alone or in combination of two or more.
[0025]
The phenolic resin may be in the form of solid, powder, or liquid. The phenolic resin is dissolved in an organic solvent in advance, or the solid or powdery phenolic resin and the solvent are simultaneously mixed with the refractory aggregate. Can be used.
[0026]
The organic solvent described below can be used as the solvent of the present invention. Examples include monohydric alcohols, dihydric alcohols, polyhydric alcohols, ketones, esters, ethers, ketone esters, ester ethers, aromatic solvents, aliphatic solvents, and the like. Of these, one or more of those having different boiling points are used in combination with a solvent having a high boiling point, such as polyhydric alcohols such as dihydric alcohols (glycols) and triols of trihydric alcohols. Can be used in combination.
[0027]
As specific examples, when the boiling point is around 60 to 100 ° C., methanol, ethanol, 1 and 2-propanol, 2-butanol, n-butanol, methyl ethyl ketone, methyl isobutyl ketone, ethylene glycol ethers, propyl acetate / isopropyl / butyl Etc. At a boiling point of about 200 ° C., there are octanol, ethylene glycol, propylene or diethylene glycols, benzyl alcohol, 1 and 3-propane or butanediol, furfuryl alcohol, furfural, diethylene glycol ethers, ethyl / propyl carbonate and the like. At a boiling point of around 300 ° C., there are glycerin, triethylene or tetraethylene glycols, triacetin, dimethyl / diethyl phthalate or dibutyl. At a boiling point of about 400 ° C., there are dioctyl phthalate / diisononyl / diisodecyl / butylbenzene and the like.
[0028]
In addition, various metal fibers and other fibers known as additives for this type of amorphous refractory, such as carbon fiber, SiC fiber, and the like, as well as animal fibers and vegetable natural fibers, Regenerated fiber such as viscose, semi-synthetic fiber such as acetate, synthetic fiber such as polyamide, polyester, polyurethane, polyolefin, polyvinyl chloride, polyvinylidene chloride, polyfluoroethylene, polyacryl, PVA, etc. And other organic fibers can be added.
[0029]
Regarding the construction of the lining structure of the present invention, the ramming material of the present invention is directly conveyed to a construction site or a construction site as a wet kneaded mixture. At this time, it can be molded in advance using an Amsler molding machine or the like, and transported in a preform state. Next, the air in the ramming material is expelled by directly or indirectly hitting or vibrating the ramming material conveyed to the construction site or the construction site with an air rammer, a vibro rammer, or electromagnetic vibration, and the blast furnace bottom, the furnace wall In order to improve the structure of the carbon brick and iron skin and the ramming material between the carbon brick and the stave, the filling is performed densely.
[0030]
【Example】
Liquid phenolic resins A to D prepared by dissolving a powdered novolak type phenolic resin in a plurality of solvents having different boiling points (bp) were prepared as shrinkable agents used in Examples of the present invention.
[0031]
Further, as the shrinkable agent used in the comparative examples, liquid phenolic resins E to H were prepared by dissolving powdered novolak type phenolic resin in a single product or a solvent having an equivalent boiling point.
[0032]
Phenol resin A is ethylene glycol (bp 198 ° C), diethylene glycol (bp 254 ° C), glycerin (bp 290 ° C), dibutyl phthalate (bp 339 ° C). 2) and a powdery novolak type phenol resin were dissolved at a weight ratio of 1: 1 to obtain a liquid phenol resin.
[0033]
Phenol resin B is ethylene glycol (bp 198 ° C), diethylene glycol (bp 254 ° C), glycerin (bp 290 ° C), dibutyl phthalate (bp 339 ° C). ) And a novolak-type phenolic resin in a powdery form in a ratio of 1: 2: 1: 1 and a powdery novolak-type phenolic resin in a ratio of 3: 2 by weight to obtain a liquid phenolic resin.
[0034]
The phenol resin C is a mixed solvent of methyl alcohol (bp 64.5 ° C.) and diisonyl phthalate (bp 403 ° C.) in the same ratio, and a powdery novolak phenol resin in a weight ratio. The phenol resin was dissolved in a ratio of 1: 1 to obtain a liquid phenol resin.
[0035]
Phenol resin D is ethylene glycol (bp 198 ° C), methyl alcohol (bp 64.5 ° C), glycerin (bp 290 ° C), butyl phthalate (bp 339). ° C) was used as a mixed solvent at a ratio of 1: 1: 1: 2, and was dissolved with a powdered novolak type phenol resin at a weight ratio of 2: 1 to obtain a liquid phenol resin.
[0036]
The phenol resin E was dissolved only in ethylene glycol (bp 198 ° C.) as a solvent at a weight ratio of 2: 1 with the powdery novolak phenol resin to obtain a liquid phenol resin.
[0037]
The phenolic resin F is obtained by mixing a mixed solvent of furfuryl alcohol (bp 170 ° C.) and 2-butoxyethanol (bp 170 ° C.) in the same ratio, and a powdery novolak phenol resin in a weight ratio. The phenol resin was dissolved in a ratio of 1: 1 to obtain a liquid phenol resin.
[0038]
The phenol resin G was dissolved only in ethylene glycol (bp 198 ° C.) as a solvent at a weight ratio of 2: 1 with the powdery resol type phenol resin to obtain a liquid phenol resin.
[0039]
The phenolic resin H is a mixed solvent of furfuryl alcohol (bp 170 ° C.) and 2-butoxyethanol (bp 170 ° C.) in the same ratio, and a powdery resol type phenol resin in a weight ratio. The phenol resin was dissolved in a ratio of 1: 1 to obtain a liquid phenol resin.
[0040]
Tables 1 and 2 show examples in which each phenolic resin was applied to the shrinkable ramming material for blast furnaces of the present invention and comparative examples. The phenolic resin in each table is indicated by + before the numerical value for external use.
[0041]
The shrinkage and thermal conductivity of the examples and comparative examples in the present invention were determined as follows.
[0042]
After adjusting the particle size of the powder mixture including the graphite raw material so as to be all under 1 mm, a liquid phenol resin is added, and after kneading, the mixture is placed in a 50φ × 50 mm mold and subjected to molding by stamping. After drying, the shrinkage after heating to 100 ° C., 200 ° C., 300 ° C. and 450 ° C. was determined.
[0043]
Also, after kneading in the same manner as above, the mixture was placed in a 40 mm × 40 mm × 160 mm mold, stamped, and dried at a temperature of less than 100 ° C. for 24 hours. The thermal conductivity after heating was determined.
[0044]
[Table 1]

In Table 1, in Examples 1 to 9 of the ramming material using a phenol resin with a solvent having a different boiling point in the present invention, it was confirmed that the shrinkage rate increased with the temperature rise from 100 ° C to 450 ° C. Was done. The thermal conductivity in this temperature range was ≧ 20 W / m · ° C., and there was no problem in the workability by stamping.
[0045]
[Table 2]

In Table 2, in Comparative Example 1, the phenolic resin A used in Example 1 was used, but the amount of the liquid was too small to allow stamping, and a sample could not be prepared.
[0046]
In Comparative Example 2, since the phenolic resin A used in Example 1 was used in a large amount, the amount of liquid was too large to cause insufficient filling, or the thermal conductivity was lowered.
[0047]
In Comparative Example 3, the liquid volume was within the specified range, but the thermal conductivity was reduced due to the small amount of the graphite raw material.
[0048]
In Comparative Examples 4 to 7, since the properties of the phenolic resin were poor, the increase in shrinkage with temperature rise was not sufficient, and the thermal conductivity was also <20 W / m · in the temperature range of 100 to 450 ° C. ° C.
[0049]
Next, a lining structure of a blast furnace constructed using the ramming material of the present invention instead of the conventional ramming material will be described with reference to the drawings.
[0050]
FIG. 1 is a longitudinal sectional view of a blast furnace side wall and a furnace bottom portion using a shrinkable ramming material for a blast furnace of the present invention, and in order from the outside of the furnace, an iron shell 1, a stave 2, a ramming material 3, and a carbon brick 4 in this order. It is lined.
[0051]
The use of the shrinkable ramming material of the present invention for the ramming material 3 causes thermal stress due to the thermal expansion of the carbon brick 4 to generate squeezing force, that is, absorbs the compressive stress on the ramming material 3 and causes cracks. Since the stove 2 is no longer used and has good thermal conductivity, the cooling effect of the stave 2 is improved, and damage to the steel shell 1 can be prevented.
[0052]
In FIG. 1, reference numeral 5 denotes a carbon protective ring brick, 6 denotes a stamp allowance made of a ramming material to which the present invention can be applied, and 7 denotes a protective brick.
[0053]
Although not shown, there is also a lining structure in which an iron shell 1, a ramming material 3, and a carbon brick 4 are arranged in this order in addition to the present embodiment. Also in this case, the thermal stress of the carbon brick 4 can be reduced, and a long-term stable operation of the blast furnace can be achieved. As for the cooling method, a water-cooling jacket is provided outside the steel shell 1.
[0054]
【The invention's effect】
(1) The shrinkable ramming material of the present invention and the lining structure using the ramming material are used for the thermal expansion of the carbon brick at the bottom and the wall of the furnace at about 60 to 450 ° C. during long-term operation of the blast furnace. Can be continuously absorbed and relaxed by the shrinkage of the ramming material, thereby preventing the carbon brick from cracking and deformation of the stave or steel shell due to the thermal stress.
[0055]
(2) Since the shrinkable ramming material of the present invention has high thermal conductivity, the temperature of the carbon brick can be lowered by heat taken from the back surface of the carbon brick, and as a result, the thermal expansion of the carbon brick is suppressed. And contributes to prolonging the life of the blast furnace.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a blast furnace wall and a furnace bottom using a shrinkable ramming material for a blast furnace according to the present invention.
[Explanation of symbols]
Reference Signs List 1 steel bar 2 stave 3 ramming material 4 carbon brick 5 carbon protection ring brick 6 stamping fee of ramming material 7 protection brick

Claims (3)

It is a mixture of an aggregate containing a graphite raw material and 10 to 30% by weight of a shrinkable agent consisting of two or more solvents having different boiling points and a phenolic resin. A shrinkable ramming material for a blast furnace, wherein a void is formed and the thermal conductivity is 20 W / m · ° C. or more, and the ramming material for a blast furnace is disposed at a portion in contact with a carbon brick of a blast furnace. 10% to 30% by weight of a shrinkable agent composed of two or more solvents having different boiling points and a phenol resin with respect to the aggregate whose one or more refractory materials are within 10% by weight and the balance is a graphite material. The shrinkable ramming for a blast furnace according to claim 1, wherein the mixture is a mixture, wherein voids are formed during a temperature rise process of 60 to 450 ° C, and the thermal conductivity is 20 W / m ° C or more. Wood. It is a mixture obtained by mixing 10 to 30% by weight of a shrinkable agent consisting of two or more solvents having different boiling points and a phenol resin with an aggregate containing a graphite raw material. A blast furnace lining structure in which a void is formed and a blast furnace shrinkable ramming material having a thermal conductivity of 20 W / m · ° C. or more is disposed at a portion in contact with the carbon brick.

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