JPH10182252A - Baking repair material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a baking repair material forming carbon bonds in a hot state, not causing settling or separation, undergoing no change with the lapse of time, having high hot spreadability, requiring a short baking time after application and ensuring a high durability by blending a refractory material with specified amts. of naphthalene as a fluidizing aid and a material forming carbon bonds in a hot state. SOLUTION: This baking repair material is obtd. by blending 100 pts.wt. refractory material with 1-20 pts.wt. naphthalene as a fluidizing aid and 5-40 pts.wt. material forming carbon bonds in a hot state, mainly coal or petroleum tar pitch having <=300 deg.C softening point optionally combined with phenol. The compsn. of the refractory material is regulated in accordance with that of a base material to be repaired and preferably contains about 20-60% fine powder of <=0.3mm size used in the conventional monolithic refractories.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a baking repair material for hot repairing various smelting furnaces, molten metal containers and the like.

[0002]

2. Description of the Related Art Conventionally, as a hot repair material applied to damaged parts such as a converter wall, an AOD furnace, an electric furnace, and an LF pot, and refining furnaces, vessel walls, furnace bottoms, etc. Interburning materials and the like are used. As such a hot baking material, dolomite, a lump having a consistency obtained by kneading a refractory raw material such as magnesia with a coal tar binder, for example, in a converter, throw the steel from the furnace port after tapping into a damaged part in the furnace, It is repaired by melt flow development and baking by heat in the furnace.

[0003] The properties required as a baking material are that there is no change with time, that it has good spreadability, that it has good adhesion, that it has good durability, that baking hardening time is short, and the like.
Baking materials using coal tar binder change over time,
Although there is no problem in spreadability and durability, there is a problem that the curing time is long.

[0004] Therefore, as a method of solving the drawback of a long baking time of a bulk baking material using a conventional coal tar binder, the viscous fluidity using a liquid novolak type phenol resin is aimed at shortening the baking time. Has been proposed to improve the effect.
No. 26679 and Japanese Patent Publication No. 6-31161)
However, since the phenolic resin solution contains a solvent, the strength of the cured product is low due to the small amount of residual carbon when carbonized, and because it is a viscous, flowable baking material, There is a problem that there is a temporal change due to sedimentation and separation of particles.

[0005] Further, in order to shorten the baking time and improve the durability, the powder obtained by coating the basic refractory raw material mixed powder with pitch and / or creosote oil is treated with a fuel oil, a heavy oil as a wetting agent, C ₉ There has been proposed a powder baking material obtained by adding an aromatic petroleum resin mainly composed of a fraction (Japanese Patent Laid-Open No. 4-170).
No. 370) has an excellent durability because the curing time is short and the strength of the cured product due to carbon bonding is high, but the solidification occurs during storage in summer due to creosote oil or heavy oil added as a combustion aid or wetting agent. There is.

Further, a baking material in which a substance that forms a carbon bond when heated and a lactam is added as a fluidization aid has been proposed (JP-A-6-157149), but the lactam has a deliquescent property. There is a problem that it is strong and that it is converted into a polyamide by ring-opening polymerization in the presence of water and an alkali metal, and there is a problem that it is solidified during storage in the summer or under high-temperature and high-humidity conditions.

Further, a baking material to which a substance which forms a carbon bond by heating and diphenyl or diphenylamine as a fluidization aid is added has been proposed (Japanese Patent Laid-Open No. 8-169).
772) is not sufficient in adhesive strength as compared with the conventional one.

[0008]

DISCLOSURE OF THE INVENTION The present invention is directed to repairing a carbon-bonded brick such as magnesia-carbon brick used in various refining furnaces from the viewpoint of adhesiveness to a base material and durability. The objective is to provide a baked powder repair material with high durability, which has a carbon bond formed by heat, has no sedimentation separation and changes with time, has a large spreadability in heat, has a short baking time after construction, and has high durability. .

[0009]

The baking repair material of the present invention forms a carbon bond between 1 part by weight and 20 parts by weight using naphthalene as a fluidizing aid and 100 parts by weight of a refractory material. It is characterized in that the substance is blended at a ratio of 5 to 40 parts by weight.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The refractory material used in the present invention can be a material suitable for a base material used for a repaired part. For example, basic oxides such as magnesia, dolomite, calcia, alumina, chromia Neutral oxides, such as
One or a combination of two or more of acidic oxides such as silica, zircon and zirconia, and non-oxides such as carbon, silicon carbide and silicon nitride. The particle size of the refractory material is preferably adjusted to about 20% to 60% of fine powder having a size of, for example, 0.3 mm or less, which is used for ordinary amorphous refractory materials.

[0011] Further, tar and pitch can be mainly used as a substance which forms a carbon bond when heated, and phenol resins can be used in combination. The amount of refractory material 1
5 parts by weight to 40 parts by weight, more preferably 10 parts by weight to 30 parts by weight with respect to 00 parts by weight. If this amount is less than 5 parts by weight, a sufficient carbon bond will not be formed, and the construction will be inferior in strength and adhesiveness. If it exceeds 40 parts by weight, the construction will have a large apparent porosity, and the slag resistance will be poor. The pitch used in the present invention may be coal-based or petroleum-based, and its softening point is melted by furnace heat and has a role of making it a fluid state, so the softening point is limited to 300 ° C. or lower. And usually 100 to 200 ° C.

The phenol resin is preferably a thermoplastic novolak type resin, and has a melting point of 120 ° C.
The following may be used at room temperature in powder or flake form.

Further, naphthalene used in the present invention is:
Purified naphthalene obtained as a by-product of coal carbonization, scaly crystals with white or colorless luster, melting point 80.3
C., boiling point 210.degree. C., no hygroscopicity, insoluble in water, extremely compatible with pitch, and melts hot with the pitch to exhibit excellent flow promoting action of the baking material, 210.degree.
At the above-mentioned temperature, it evaporates and burns quickly to act on the carbonization promoting action of the pitch, and exhibits the effect of shortening the curing time. In addition, there is an excellent effect that the wettability between the pitch, which has been reduced in viscosity due to the high compatibility with the pitch, the refractory aggregate, and the furnace wall is improved, and high adhesive strength is obtained.

The amount of addition is 1 to 20 parts by weight, preferably 1 to 15 parts by weight, per 100 parts by weight of the refractory aggregate. If the amount is less than 1 part by weight, the spreadability of the baked material during heating is insufficient, and if it exceeds 20 parts by weight, the construction becomes porous and the corrosion resistance decreases, and neither is preferable.

[0015] In addition, a metal powder or the like can be used in combination for the purpose of preventing oxidation and improving the strength of the construction body.

In the present invention, when a powdery binder is used, the binder is used as a powdery repair material, and when a binder is used in a liquid state, it becomes a clay. Either form is easy to transport and store, and hardly changes over time.
In using the baking repair material of the present invention, it is only necessary to put it in a repairing site such as various refining furnaces by an appropriate method and bake it.

The refining furnaces to be repaired have at least 600
℃ or higher, the naphthalene contained in the repair material of the present invention is melted by the retained heat of the furnace wall, the entire repair material spreads in a fluid state, flows to the details of the repair site, and the refractory material is removed. After filling and curing of the repair material by the action of the binder, a carbon bond is formed. The naphthalene melts, starts to flow, volatilizes, decomposes, and burns away, so that the baking time is completed in a short time.

In the present invention, since a glidant having excellent compatibility is used, it is more excellent in filling property, adhesiveness and durability than a baked material using only tar or pitch. Furthermore, naphthalene is reduced in molecular weight by volatilization and decomposition, and is burned by the heat in the furnace, so there is little smoke, and the heat of combustion also promotes the carbonization of binders such as tar, pitch, and phenol resin, which are slow in thermosetting due to the heat of combustion. You. Hereinafter, the present invention will be described with reference to examples.

[0019]

Examples 1 to 5 are examples relating to a baking repair material of the present invention. Comparative Example 1 is a refractory material to which a thermoplastic liquid phenol resin is added, and Comparative Example 2 is a pitch and a fluidizing agent. Comparative Example 3 was obtained by adding pitch and diphenyl as a fluidization aid to refractory material, Comparative Example 4 was obtained by adding pitch to refractory material, and Comparative Example 5 was obtained by adding pitch to refractory material. Creosote oil and heavy oil are added as a combustion aid and a wetting agent.

800 g of the composition shown in Table 1 was put on a castable plate in a furnace maintained at 1000 ° C., and after extinguishing, the castable plate was taken out of the furnace and the average diameter of the spread of the baked material was measured as spreadability. did.

The curing time was as follows. A ring-shaped metal frame having an inner diameter of 53 mm × 40 h was placed on magnesia brick kept at 1000 ° C., 200 g of a sample was charged, and the time until the whole was cured was measured. Immediately after the sample was cured, the adhesive strength was measured by a shear adhesive strength measuring machine. In a furnace maintained at 1000 ° C., 1 kg was placed in an enclosure made of magnesia brick.
After charging and curing, the physical properties of the cured product were also measured.

Further, as a storage test, 150 g of a sample was filled in a metal frame having an inner diameter of 50 mm × 50 h at a temperature of 50 ° C.
A material that collapsed when subjected to a load of 0.25 kg / cm ² and pulled out after holding for 1 hour was regarded as good. The storage property of the baking material kneaded with the liquid phenol resin was tested at the depth of the upper separated liquid layer when the kneaded material was left at room temperature for 3 days.

The results are shown in Tables 1 and 2 simultaneously. The compositions in the table are parts by weight.

[0024]

[Table 1]

^{* 1} Novolak resin having a melting point of 85 ° C. (number average molecular weight 815)

[0026]

[Table 2]

^{* 2} Novolak resin (number average molecular weight 26
5) 50% triethylene glycol solution, viscosity 55P
(25 ° C.) (manufactured by Sumitomo Durez Co., Ltd.) The baking repair material of the present invention had better fluidity represented by spreading property and baking time represented by curing time as compared with the comparative repair material. Furthermore, it is considered that the corrosion resistance and the durability are significantly improved due to the low porosity and high adhesive strength of the construction body.

Further, in the storage test showing the change over time, the baking repair material of the present invention does not show a solidification phenomenon, but the baking repair materials of Comparative Examples 2 and 5 show a solidification phenomenon. Changes are expected. Further, in Comparative Example 1 using a liquid phenol resin, sedimentation and separation of coarse particles were observed, and changes with time were observed.

[0029]

Since the baking repair material of the present invention uses naphthalene as a fluidization aid, it has good hot spreadability, curability, adhesiveness, physical properties of the construction, and durability of the baking material. Leads to improvement. Moreover, since there is no change with time such as solidification and sedimentation in summer, it is an excellent baking repair material that can be easily transported and stored, is easy to handle and perform, and can be baked in a short time.

Claims (2)

[Claims] 1 to 20 parts by weight of naphthalene as a fluidizing aid, and 5 to 40 parts by weight of a substance capable of forming a carbon bond by heating based on 100 parts by weight of a refractory material.
A baking repair material characterized by being blended in parts by weight. 2. The baking repair material according to claim 1, wherein the substance that forms a carbon bond when hot is a pitch having a softening point of 300 ° C. or less.