KR100356179B1 - Graphite-containing castable refractory composition - Google Patents

Abstract

PURPOSE: A castable refractory containing graphite which has excellent heat resistance, impact resistance and anti-corrosive property as well as long working life and can be recycled is provided. CONSTITUTION: The amorphous castable refractory containing graphite is characterized in that the graphite is contained as waste refractory type containing small particulate graphite having particle diameter less than 0.1 mm on which a hydrophilic surfactant is coated, medium particulate graphite having particle diameter of 0.1-1 mm on which a resin is coated, and alumina graphite having particle diameter of 1-5 mm, wherein the content of small particulate graphite and medium particulate graphite is 1 to 5 wt% and 1 to 10 wt%, respectively, and the content of waste refractory containing graphite is 5 to 30 wt% to be 1 to 5 wt% of the amount of graphite added to the material.

Description

Graphite-containing castable refractory composition

The present invention relates to a castable refractory material that can be used in furnace equipment, such as ladle wall, ladle bottom, ladle well block, blast furnace barrel, crossroad car, etc., more specifically, heat resistance, thermal shock resistance And a graphite-containing castable refractory having excellent corrosion resistance.

Graphite-containing refractory containing graphite is widely used in the field of steelmaking and steelmaking because it has excellent properties such as heat resistance and thermal shock resistance, and is difficult to get wet with molten iron, molten steel, and molten slag and thus shows excellent corrosion resistance. However, in the case of graphite-containing orthogonal refractory, it requires a lot of work in manufacturing and construction, but requires a lot of cost and working time as a whole. As a result, in recent years, in the field of refractory, manufacturing and construction are simple, so that the portion of the amorphous refractory, which is relatively low in cost and independent of the shape of the construction site, is gradually increasing.

Amorphous refractory is to construct the composition of the powder mixed in the field by adding water in the field, when containing graphite, the graphite is hydrophilic when mixed with water will increase the water content. This increase in water content causes a decrease in physical properties such as increasing porosity and lowering strength after drying.

Therefore, many methods have been studied to solve the weak point of such graphite-containing amorphous refractory. Among them, there is a method of increasing the hydrophilicity by surface-treating the graphite surface or coating the resin. However, the method of increasing the hydrophilicity by coating the graphite powder with the surfactant has a limit on the amount of graphite that can maintain the strength, so that when a large amount is added to form amorphous refractory, no bond is formed in the matrix so that the strength is increased. There is a problem of low. In addition, the method of manufacturing granules by coating the organic resin on the graphite and using the amorphous refractory material does not effectively prevent the penetration of slag because the graphite coated with the organic resin is present in the granulated portion and the graphite is not present in the fine powder. In addition, since the porosity is increased by evaporation of volatile components in the resin at a high temperature when a large amount is added, there is a problem in that physical properties such as corrosion resistance are lowered.

On the other hand, in recent years, active research on the reuse of waste refractories has been actively conducted to cope with environmental problems, but the ratio of recycling is still very small.

Accordingly, the present inventors have repeatedly conducted research and experiments to solve the above problems, and based on the results, the present invention proposes the present invention. By appropriately controlling the form of neutral graphite and pulverized graphite-containing waste refractories coated with resin on the surface and adding the content at a proper ratio, waste refractories can be recycled while preventing the decrease in strength and water consumption. It is an object of the present invention to provide a graphite-containing castable refractory having excellent heat resistance, heat shock resistance and corrosion resistance.

In the present invention for achieving the above object, in the amorphous castable refractory containing a part of graphite, the graphite has a particle diameter of 0.1mm or less, the surface of which is coated with a hydrophilic surfactant, the resin is coated on the surface of the particle size 0.1- Neutral graphite granulated to 1mm and alumina graphite-containing waste refractories having a particle diameter of 1mm or more, wherein the fine graphite is 1-5% by weight, the neutral graphite is 1-10% by weight, and the added graphite The graphite-containing waste refractories are related to graphite-containing castable refractories in an amount of 5-30 wt% so that the content is 1 to 5 wt%.

Hereinafter, the present invention will be described in more detail.

Generally, castable refractory compositions are known in many varieties, representative of which are 75-95% by weight of aggregate raw materials and 2-15% by weight of alumina cement, and 0-15% by weight of other ultrafine raw materials. And the castable refractory composition formed. The castable refractory composition as described above is usually used by adding 4-15% by weight of water, kneading, pouring into a mold of a desired form, curing and drying.

In the present invention, 1-5% by weight of particulate graphite having a particle diameter of 0.1 mm or less, whose surface is coated with a hydrophilic surfactant, and the surface of the castable refractory composition, are granulated to a particle size of 0.1-1 mm. It is prepared by adding 1-10 wt% of neutral graphite and 1-30 wt% of graphite containing waste refractory to a content of 5-30 wt%.

The fine graphite having a particle size of 0.1mm or less coated with a hydrophilic surfactant is contained in an amount of 1-5% by weight. If the content is less than 1% by weight, the effect of graphite addition such as preventing slag penetration due to the addition of graphite is weak. This is because when the amount exceeds 5% by weight, the amount of the added water increases, which not only lowers the physical properties but also the strength. At this time, the particle size of the surface-treated graphite is preferably 0.1mm or less.

The hydrophilic surfactant that coats the surface of the particulate graphite is not particularly limited, and both low-foaming and hydrophilic nonionic and anionic surfactants such as glycolic acid soda, naphthalene sulfonic acid soda, alkylbenzene sulfonic acid, and the like are possible, and cationic Although surfactants are possible, most cationic surfactants are toxic and should be avoided. Moreover, you may use polymer dispersing agents, such as methyl cellulose.

Surfactant treatment of the graphite can be carried out by a conventional method, for example, by adding 1-5% by weight of the surfactant to the graphite with graphite, mixed with adding water to coat the surfactant on the graphite surface After drying, use.

Neutral graphite, which had a resin coated on the surface and granulated to a particle size of 0.1-1 mm, contained 1-10% by weight, but the addition amount was less than 1% by weight, and the graphite addition effect was insignificant. This is because the dispersibility in the table is poor and the resin is pyrolyzed when used at a high temperature, and the porosity is increased by the generated gas, thereby preventing the formation of a dense sintered body. At this time, the particle diameter of the granulated graphite is preferably 0.1-1mm.

The resin coating the graphite is not particularly limited, and examples thereof include hydrophilic phenolic resins, fran resins, xylene resins, melamine resins, acrylic resins, and the like. It is preferable to use.

Granulation with the resin can be carried out by a conventional method. For example, 10-40% by weight of resin is added to graphite fine powder, and the mixture is pressurized and then dried.

The graphite-containing waste refractories having a particle diameter of 1 mm or more are contained in 5-30% by weight. If the content is less than 5% by weight, the effect of graphite addition is insignificant. Because it becomes. At this time, the size of the waste refractories is preferably a particle size of 1mm or more, it is required to be equal to or smaller than the maximum particle size of the refractory aggregate is more preferably to limit the particle size to 1 ~ 5mm.

The graphite-containing waste refractories may include alumina and magnesia, and both types may be used depending on the material of the amorphous refractory material. In general, since the waste form refractory has a graphite content of about 15%, the amount of graphite added due to the addition of the graphite-containing waste refractory is about 1-5% by weight.

Hereinafter, the present invention will be described in more detail with reference to Examples.

Example

Crushing of graphite and alumina-carbon waste refractory bricks resin-coated with 30% by weight of finely divided graphite and phenolic resin surface-treated with 1% by weight of alkyl benzene sulfonic acid in a castable refractory composition having a compounding ratio as shown in Table 1 below Add water and knead it with water (flow value) 150 and pour it into the mold.40x40x160mm (porosity, bending strength test), 110 (length) x40 (height) x87.8 (upper side) x115.9 (lower side) mm Molded to size cross-cutting (for erosion test) and 60 x 60 x 60 mm (for spalling test). The molded article was cured at room temperature for 24 hours, and then dried at 100 ° C for 24 hours. Further, the dried product was reduced and calcined at 1400 ° C. for 3 hours to prepare a fired product. The apparent porosity and the bending strength of the dried product and the fired product were obtained and shown in Table 1 below.

In addition, by repeating the temperature increase ↔ water cooling up to 1400 ℃ to repeat the number of times until some of the specimen is dropped to the spalling resistance and the results are shown in Table 1 below.

In addition, after performing a rotary erosion test with ladle slag (CaO / SiO ₂ : 6.0, Al ₂ O ₃ : 21%), the erosion depth and the slag penetration depth were measured. The rotary erosion test measures the slag penetration depth and erosion depth after repeating 1600 ℃ x 1 hour x 10 times in a rotary erosion tester, by the following formula (1) and (2) based on Comparative Example (7) The infiltration index and the corrosion resistance index were obtained, and their values are shown in Table 1 below.

As shown in Table 1, Inventive Example (1-3) was changed in the content of the surface-treated finely divided graphite, resin coated neutral graphite and waste refractory within the scope of the present invention, Comparative Example (1-7) ) Used castables made to contents outside the scope of the present invention.

Inventive Example (1-3) was superior in strength to Comparative Example (1-7), and it was found that the penetration and erosion of slag were greatly suppressed, and the properties such as spalling resistance and slag infiltration index were excellent.

As described above, according to the present invention, by containing the surface-treated finely divided graphite, resin-coated neutral graphite, and graphite-containing waste refractories together in castable refractories, strength, nass compared with conventional graphite-containing castable refractories As it improves pollenability and penetration into slag and erosion, it is not only provided with the effect of increasing the service life of the refractory when applying the obtained refractory to ladle walls, ladle bottoms, ladle well blocks, blast furnaces, cross talk cars, etc. The effect of recycling it is also provided.

Claims (3)

In the amorphous castable refractory containing some graphite, The graphite is in the form of particulate graphite having a particle size of 0.1 mm or less, the surface of which is coated with a hydrophilic surfactant, neutral graphite of which the resin is coated on the surface and granulated to a particle size of 0.1-1 mm, and alumina graphite containing waste particles having a particle diameter of 1 to 5 mm. In this case, the fine graphite is 1-5% by weight, the neutral graphite is 1-10% by weight, and the graphite-containing waste refractory is 5-30% by weight so that the content of the graphite is 1-5% by weight. Graphite-containing castable refractory, characterized in that contained in a content of% The method of claim 1, The surfactant used in the surfactant treatment is graphite-castable refractory, characterized in that selected from the group consisting of soda glycolic acid, sodium naphthalene sulfonic acid, sodium alkylbenzene sulfonic acid. The method of claim 1, The resin is a graphite-containing castable refractory, characterized in that selected from the group consisting of phenol resin, frans resin, xylene resin, melamine resin and acrylic resin.