KR19980036817A - Carbon Spray Material for Steelmaking Containers - Google Patents

Abstract

The present invention relates to a carbon-based spray material (aka Gunning material) for steelmaking vessels used for hot repair of molten metal containers such as converters, to a total of 100wt% of magnesia aggregate, dolomite aggregate, carbon, It contains 2-8 wt% of inorganic binder of silica and 1-5 wt% of antioxidant. The formed spray material is sprayed using hot water on a molten metal container refractory wall such as a converter to spray the pitch and resin in the material. After fluidizing, carbonization produces a strong carbon bond structure on the refractory wall, which has the effect of extending the life of the furnace and reducing the cost, shortening curing time, improving adhesion and preventing carbon oxidation, thereby improving corrosion resistance. There is.

Description

Carbon Spray Material for Steelmaking Containers

The present invention relates to a carbon-based spray material (aka Gunning material) for steelmaking vessels used for hot repair of molten metal containers such as converters.

In general, molten metal containers such as converters are spray repaired on the furnace walls for the purpose of extending the life. In addition, in order to improve the operation rate of the container, this repair is carried out hot. In the initial spray repair, a silica-based inorganic binder was used, but the solvent content was severely lowered due to the severe operating conditions of the furnace, that is, high temperature blowing, and thus the frequency of repair was increased. Recently, dolomite (MgO.CaO) phosphate-based Spraying materials are used to contribute to the prolongation of furnace life and reduction of raw units.

In addition, a phosphorus-free carbonaceous-based spray material focusing on dephosphorization and adhesiveness with Mg-carbon lead for special steel fabrication and solvent resistance is used in parallel, and shows good results. As the carbon-based spray material, as described in Japanese Patent No. 55-42218, a spray material using a resin such as phenol resin and furan resin has been proposed as a binder, and Japanese Patent No. 59-8672 discloses a spray material. Zero spray material was proposed, and Japanese Patent No. 4-280877 also proposed a spray material in which a binder was added to the resin and the pitch. Such a material was particularly suitable for hot repair, as the binder was carbonized by royal after spraying to produce a carbon bond excellent in corrosion resistance and adhesive strength.

However, resins and pitches used to produce carbon bonds are difficult to mix with construction moisture, require curing time to burn and attach, and oxidize with water and air. In addition, as the furnace operation conditions have become more severe in recent years, such as high temperature smelting of converters, strong adhesion is required at a fast curing time, and there is a problem in that the contents should be further improved.

Accordingly, the present invention has been made to solve the above-mentioned problems, and the carbon-based spray material for spraying and repairing the fireproof wall of the molten metal container such as a converter using hot water, the pitch and the resin in the material After the fluidization, carbonized carbon-based spray materials for carbon steel containers are carbonized to create a strong carbon bond structure, which contributes to the life of the furnace and reduction of raw units, and to shorten the curing time, and to increase the corrosion resistance by preventing adhesion and oxidation of carbon. The purpose is to provide.

The present invention for achieving the above object is a spray material made by mixing 2-8 wt% of inorganic binders of silica and 1-5 wt% of an antioxidant with respect to a total of 100 wt% of magnesia aggregate, dolomite aggregate, and carbon. It is characterized by.

In addition, the raw material (magnesia + dolomite) to the subsidiary material (carbons) of the raw material and the auxiliary material consisting of magnesia aggregate, dolomite aggregate, carbon, characterized in that the composition ratio of 9: 1 to 7: 3.

In addition, among the raw materials of magnesia and dolomite, the composition ratio is characterized by consisting of 9: 1 to 5: 5.

In addition, carbon as an auxiliary material is composed of a pitch and a novolak phenol resin, the ratio is characterized in that consisting of 5: 5 to 9: 1.

Hereinafter, preferred embodiments of the present invention will be described in detail.

To the total 100 wt% of the magnesia aggregate, the dolomite aggregate, and carbon, 2 to 8 wt% of the inorganic binder of silica and 1 to 5 wt% of the antioxidant are added. In addition, the raw material (magnesia + dolomite) to the subsidiary material (carbons) is composed of 9: 1 to 7: 3 among raw and auxiliary raw materials including magnesia aggregate, dolomite aggregate and carbon.

At this time, the composition ratio of magnesia aggregate and dolomite aggregate is composed of 9: 1 to 5: 5, and the carbon as an auxiliary material is composed of pitch and novolak phenol resin, and the ratio is composed of 5: 5 to 9: 1. do.

At this time, as an antioxidant added to prevent oxidation of carbon, metals such as aluminum, silicon, magnesium, and alloys thereof are used. This is an additive that must be added in the carbon-based spray material, and its content is most suitably 1 to 5% based on 100% of the raw and auxiliary raw materials. If 1% or less is added, the main function of the antioxidant is not exhibited, and if it is 5% or more, it is unnecessary to increase and increase the flux.

Hereinafter, more specific examples and comparative examples of the present invention will be described.

Example

Table 1 shows the examples and comparative examples of the present invention and the results. The wall temperature of the furnace on which the magnesia-carbon brick is stacked is heated to 1200 ° C., and then sprayed using a dry gun to spray the spray material. The adhesion rate was measured. The curing time was taken 500g of the sample to which 15% of water was added, put into 1000 ℃ and burned to measure the curing time attached. In addition, a specimen (sample length 35mm) was made for the sample, and the physical properties and corrosion resistance at 1500 ° C were measured.

Comparative example

Comparative Example 1 is the case of using only magnesia aggregate as a raw material, Comparative Example 2 is the case using only pitch in carbon, Comparative Example 3 is the case of adding the phosphate binder in the inorganic binder, Comparative Example 4 does not add the antioxidant If not, the adhesion rate, curing time, physical properties, and corrosion resistance were measured in the same manner as in Example.

Analysis and test results of Examples and Comparative Examples division Example Comparative Example One 2 3 4 Raw material (wt%) Magnesia aggregate 50 100 50 50 50 Dolomite Aggregate 50 - 50 50 50 Raw materials pitch ○ ○ ○ ○ ○ Phenolic Resin ○ ○ - ○ ○ Binder Silicate ○ ○ ○ ○ ○ Phosphate - - ○ ○ - Antioxidant ○ ○ ○ ○ - Adhesion Rate (%) 90 85 90 90 90 Curing time (min) 4.5 4.5 6.0 4.5 4.5 Physical property (1500 ℃) Rate of change (%) -2.1 -1.7 -2.5 -2.4 -2.4 Volume specific gravity 2.2 2.5 2.0 2.2 2.2 Porosity (%) 32 30 37 32 32 Compressive strength (kg / cm ² ) 20 25 18 14 13 Bending strength (kg / cm ² ) 15 19 12 ² 10 10 Corrosion resistance Erosion Length (mm) 3.2 3.5 4.0 5.1 5.5 Erosion Rate (%) 9.0 10.0 11.4 14.6 15.7

Compared to the embodiment of the present invention of Table 1, in Comparative Example 1, the compressive strength and the bending strength are large, the porosity is small, while the curing time is the same as the embodiment, while the adhesion rate, which is the subject of the present invention, is low and the volume The specific gravity is large, and in the case of Comparative Example 2, the adhesion rate is similar to that of Example, while the curing time is long, the porosity is large, the compressive strength and the bending strength are small, and in the case of Comparative Examples 3 and 4, the adhesion rate and curing time are The same as the embodiment, but the compressive strength and the bending strength is much lower than the example, there was a weakness that the corrosion resistance is lowered.

Therefore, in the case of the embodiment according to the present invention, the adhesion rate was large, the curing time was small, the proper porosity and the compressive strength were shown, and the corrosion resistance was satisfactory.

As described above, the spray material according to the present invention is carbonized to create a strong carbon bond structure, which contributes to the life extension of the furnace and reduction of the unit, and shortens the curing time, and prevents adhesion and oxidation of carbon, thereby improving corrosion resistance. .

Claims (4)

A carbon-based spray material for steelmaking vessels, characterized in that 2-8 wt% of inorganic binders of silica and 1-5 wt% of antioxidants are blended with respect to 100 wt% of magnesia aggregate, dolomite aggregate, and carbon. A raw material (magnesia + dolomite) to a subsidiary material (carbons) is composed of 9: 1 to 7: 3 according to claim 1, wherein the raw material and raw material consisting of magnesia aggregate, dolomite aggregate and carbon is composed of 9: 1 to 7: 3. Carbon spray material for steelmaking containers. The carbonaceous spray material for steelmaking container according to claim 1, wherein the composition ratio of magnesia and dolomite is 9: 1 to 5: 5. 2. The carbon-based spray material for steelmaking container according to claim 1, wherein the carbons, which are secondary ingredients, are composed of pitch and novolak phenol resin, and the composition ratio is 5: 5 to 9: 1 .