KR20080099216A - Refractory repairing material for equipment of iron/steel making, method for preparing thereof and composition comprising the same - Google Patents

Abstract

A method for manufacturing raw materials of repair materials for manufacturing facilities of steel and iron is provided to have excellent sinterability and a corrosion resistance and to increase a lifetime of interior materials of refractories of the steel and the iron. A method for manufacturing raw materials of repair materials for manufacturing facilities of steel and iron comprises steps of: comprising one or more selected from a group consisting of magnesite, light magnesia and burned magnesia; pulverizing and mixing one or more minerals selected from group consisting of olivine, serpentine, talcum and pyroxene (B) and one or more minerals selected from a group consisting of quartz and silica (C); molding and drying the pulverized and mixed materials; and plasticizing or fusing the dried materials.

Description

Refractory repairing material for equipment of equipment for iron / steel making, method for preparing honey and composition comprising the same}

The present invention relates to a fire resistant repair material of a steelmaking / steelmaking facility, a manufacturing method thereof, and a repair material including the same. More specifically, the present invention is a method for manufacturing a raw material of fire-resistant repair material for repairing the interior of various equipment such as furnace, ladle, tundish and the like used in steelmaking and steelmaking, manufactured from this manufacturing method It provides the raw material and the repair material composition containing this raw material.

In various furnaces such as converters, electric furnaces, etc., refractory materials are constructed inside a container-shaped metal casing or frame, and once the operation is started, the refractory is protected after processing a certain amount of molten steel except for the blast furnace which does not turn off until newly constructed. In order to repair the damaged or damaged parts, the furnace wall is periodically repaired.

The furnace is filled with molten steel of 1500 ℃ or higher, and various chemical reactions such as decarburization reaction and deoxidation reaction occur, so that the furnace wall contacting with the molten steel is damaged by erosion by molten steel. Accidents may occur.

As mentioned above, the furnace wall which comes into contact with molten steel is generally made by constructing a refractory brick, and this refractory brick must not only soften at a high temperature of at least 1,500 ° C. or more, but also maintain its strength sufficiently, and must be able to withstand chemical effects. do.

In other words, refractory bricks have high fire resistance, high strength, high thermal shock resistance, and strong resistance to chemical erosion. The repair of a furnace wall made of fire bricks satisfying such conditions is performed according to the degree of erosion and damage. It can be divided into construction and partial repair. When rebuilding is not possible to normalize the damaged part by surface repair only because the degree of damage is so severe, rebuilding it with new refractory brick or rebuilding it In the case where the entire repair is required by the end of the critical life, the partial repair is performed when only the surface portion of the furnace wall is damaged and the furnace wall can be normalized only by repairing the surface portion.

Particularly, in the case of the partial repair, the furnace is heated in a hot state, and thus, the hot repair work requires considerable energy and time to heat the furnace after the furnace is completely cooled. Because it becomes.

As mentioned above, the partial or full reconstruction of the furnace wall repair has no problem after the reconstruction because it reconstructs the furnace wall using a new refractory brick, but in the case of partial repair, the fireproof material is sprayed in the hot state to the furnace wall. Because of the spraying, if the original bond between the damaged original furnace wall and the overlaid repair layer is not perfect, the repair layer is easily pulled off by molten steel, and the damaged part before the repair is suddenly further damaged, resulting in damage to the furnace wall. There is a problem that can be linked.

The furnace wall repair performed by the spray method not only serves to cultivate a damaged furnace wall but also periodically repairs the damaged furnace wall to prevent damage or erosion of a normal furnace wall caused by high temperature molten steel. It also serves to extend the life of the furnace wall by forming a coating layer for protecting the furnace wall.

The spray material used for partial repair of the spray method that is carried out hot to extend the life of various normal or damaged furnace walls as described above is a fireproof material that is attached to the furnace wall by being sprayed on the furnace wall by kneading with high pressure water using a spray gun. In addition, it should not only have excellent adhesion and corrosion resistance with the refractory bricks constituting the furnace wall, but also no thermal explosion and peeling after spraying, and a short curing time.

Silica-based inorganic binders, which have been widely used as the spraying materials, have a lower effect as the operating conditions of the furnace become more severe in order to improve steel quality. In recent years, a spray containing high-melting binder added to magnesia (MgO) or dolomite Although ash has been developed, this also has a disadvantage of low corrosion resistance and adhesion.

That is, the spray material made of magnesia or dolomite is lacking in sintering property, and the moisture is rapidly evaporated at the time of being attached to the furnace wall by hot spraying, so that the adhesion to the furnace wall is reduced.

And the adhesion of the spray material is greatly affected by the temperature of the furnace wall, because the spray is carried out at a temperature of 800 ℃ or more spray material due to the high vapor pressure repulsion is formed by the rapid evaporation of water sprayed with the spray material The rate of splashing on the surface of the furnace wall is high without being attached to the furnace wall.

In addition, the state of the spray material adhered to the furnace wall is unstable due to the repulsive force due to the vapor pressure, and is easy to fall off due to the injection impact of molten steel or the like and molten steel vortex after construction.

In other words, the spray material that is hot sprayed and has low adhesive strength should be sintered quickly because it is easily damaged until it is sintered by the heat of the furnace wall and forms a strong ceramic bond with the surface of the furnace wall. The spray material has a long sintering time, so the initial dropout rate after construction has a disadvantage in that the furnace wall protection efficiency is lowered.

And to solve the shortcomings of the spray material mainly made of magnesia or dolomite, carbon-based spray materials have been developed that produce a carbon bond excellent in corrosion resistance and adhesive strength by carbonization of the binder by spraying after the spraying, but these The resin or pitch used to produce is difficult to mix with moisture during construction, and the carbonization time is not only long, but the curing time is long, as well as oxidized by water and air.

On the other hand, the existing forsterite-based amorphous repair material used in various facilities for steelmaking / steelmaking is applied without firing or by firing MgO-SiO ₂ raw materials such as natural olivine, olivine, serpentine, talc, etc. The amount of impurities such as Fe ₂ O ₃ is large and does not form a forsterite crystal phase as a whole in the raw material, and the compactness is low, so it is difficult to be commercialized due to its weakness in corrosion resistance compared to general magnesia-based amorphous repair materials.

Accordingly, an object of the present invention is to provide a method for producing a repair material having forsterite as a main mineral, and a repair material for steel / steel equipment using the material obtained by the manufacturing method, which can solve the above-mentioned problems. do.

In order to provide the above object, the present invention does not use natural forsterite-based minerals, but synthesizes the materials necessary to theoretically have a forsterite mineral phase. to provide.

In the present invention

(A) at least one selected from the group consisting of magnesite, mild magnesia and calcined magnesia; It provides a method for producing a repair material raw material for steel or steelmaking equipment comprising the step of firing or melting at least one mineral selected from (B) and (C).

At this time, the calcined magnesia includes Dead Burned Magnesia (DBM) and the like, wherein (B) is at least one mineral selected from the group consisting of olivine, serpentine, talc and fluorite, (C) is silica and At least one mineral selected from the group consisting of silica sand.

The method of manufacturing a repair material of a steelmaking or steelmaking facility using the firing process of the method includes the following steps:

(A) at least one selected from the group consisting of magnesite, mild magnesia and calcined magnesia; Grinding and mixing one or more minerals selected from (B) and (C);

Shaping and drying the mixed and ground products; And

Firing the dried molding.

In addition, the manufacturing method of the repair material of the steelmaking or steelmaking equipment using the melting process of the above method comprises the following steps:

(A) at least one selected from the group consisting of magnesite, mild magnesia and calcined magnesia; Grinding and mixing one or more minerals selected from (B) and (C); And

Melting the mixed and ground product.

In the pulverizing and mixing step, the final magnesia content of the raw material to be prepared may be 50 to 80% by weight, preferably 60 to 70% by weight, and then mixed, or mixed and ground.

For the repair material prepared above, forsterite is a main mineral phase and periclase is a negative mineral phase.

Specifically, in order to manufacture the repair material raw material of the present invention, in order to grind the starting materials described above, it is preferable to grind into fine powder when the firing process is used, and when the melting process is used, grinding of the degree of grinding (particle diameter of 10 mm or less) You can do it.

Next, the starting materials are weighed so that the magnesia content of the final repair material is 50 to 80% by weight, preferably 60 to 70%, and kneading is performed for at least 20 minutes to prevent ubiquity by adding water in a kneader.

Next, in the case of using the firing process, the kneaded material kneaded well is formed into a ball shape or a brick shape using a molding machine and then dried. The drying temperature is performed at 110 ° C. or more for 10 hours or more to remove moisture.

The dried ball or brick shaped body is charged to a kiln and maintained at a temperature of 1500 ° C. or higher, preferably 1500 to 1800 ° C. for at least 3 hours to form a compact plastic body and form a forsterite mineral phase.

On the other hand, in the case of using a melting process, the kneaded kneaded material is introduced into an electromelting furnace to be melted, cooled by natural drying, or the like, and the molten ingot is crushed or cut into a required size to be used as a repair material. Can be used.

The melting temperature varies with the composition of the mixture but is carried out at approximately 1850-2200 ° C.

In addition, the present invention provides a furnace wall repair material prepared by the above-described manufacturing method.

The present invention also provides a repair material for a steelmaking or steelmaking facility further comprising the above-described furnace wall repair material and optionally magnesia.

The repair material may further include a silicic acid-based binder or a phosphoric acid-based binder.

When preparing the repair material is to crush the raw material produced by the firing to mix with magnesia or a binder.

The steelmaking or steelmaking facility may include an electric furnace, a converter, a ladle, a RH (Rheinstahl Heraeus) deposition tube or a tundish, but the present invention is not limited thereto. Applicable

The repair material may be applied in a form that can be easily attached to the inner wall of the facility, such as a spray material or a coating material.

The amorphous repair material made by using the raw material prepared by the forsterite-based raw material synthesis method according to the present invention has excellent sintering resistance and corrosion resistance and can improve the life of refractory interior materials of steel and steel.

As described above, the present invention includes magnesite (MgCO ₃ ), light burned magnesia, calcined magnesia, olivine, olivine, serpentine, fluorite, silica, silica, etc., as a source of magnesia (MgO) and silica (SiO ₂ ). Theoretically, the magnesia (MgO) content in which the forsterite mineral phase is produced is combined to be 50 to 80% by weight, preferably 60 to 70%. Synthetic method.

Amorphous repair material applied with synthetic raw materials made by this manufacturing method has better corrosion resistance than conventional MgO-SiO ₂ based raw material, and has better sintering and corrosion resistance than general magnesia-based amorphous repair material, which can lead to longer life of refractory interior materials. The product can be manufactured.

As shown in Table 1, conventional olivine-based raw materials have a low melting point, so that erosion may increase when applied to operating temperatures of about 1550 to 1700 ° C. in steelmaking and steel making synthetic forsterite raw materials to improve corrosion resistance. .

Mineral water Composition Melting point (℃) Other Forsterite 2MgOSiO ₂ 1890 Thermal stability Faylite 2FeOSiO ₂ 1280 Antigorite 3MgO · 2SiO ₂ · 2H ₂ O 800 ° C .: Forsterite progress Pericles MgO 2800 Thermal stability Enstatite MgOSiO ₂ Transition above 1050 ℃ Clinoenstatite MgOSiO ₂ 1577 Talc 3MgO · 4SiO ₂ · H ₂ O 900 ~ 1000 ℃ dehydration transition

Hereinafter, the present invention will be described in more detail by the following examples. The following examples are merely to illustrate the invention is not limited to the contents of the present invention by the following examples.

First, the chemical components of the starting materials for preparing the repair material of the present invention are illustrated in Table 2 below.

division Natural olivine Calcined olivine Magnesite (MgCO ₃ ) Small MgO burr Chemical composition (%) MgO 46.80 50.79 47.01 88.61 0.00 CaO 0.48 1.12 0.90 1.01 0.07 Al ₂ O ₃ 0.92 0.51 0.03 0.08 0.09 Fe ₂ O ₃ 8.36 6.88 0.30 0.60 0.05 SiO ₂ 38.38 38.19 0.31 0.91 99.67 L.O.I * 4.48 0.76 51.39 8.79 0.10

* L.O.I: Loss of Ignition

Table 3 below shows the combination ratios of the starting materials of the prior art, the examples and the comparative examples. Conventional examples have conventionally been used as raw materials for repair materials, and comparative examples are those in which the final magnesia content is outside the scope of the present invention.

Combining the starting materials of the following Table 3, finely pulverized and molded into a size 230 × 114 × 65mm, dried in a test drying furnace for 24 hours at 110 ℃ and put into a shuttle kiln (shut Kiln) and calcined at 1,500 ℃ 3 hours. Physical properties of the synthesized raw materials are also shown in Table 3.

Table 4 shows an example prepared by applying the synthesized raw material as an electric repair spray material, and also compared the results are shown.

In Table 4, the compressive strength and the residual linear expansion change rate were tested and calculated by KSL 3503 and KSL 3117, respectively, and the adhesion strength was applied at a thickness of 5 mm on the surface of the refractory brick for steel furnace furnace walls at 1350 ° C. After firing and attaching, 1Kg of steel balls were dropped 10 times at a height of 50 cm on the surface thereof, and cracks generated in the fired composition layer were observed. This progressing state '○', there is no abnormality or a case where the fine crack occurred only at the point where the strong ball is dropped as '◎'.

As can be seen in Table 4, in the electric furnace spray material refractory to which the synthetic material prepared according to the present invention was applied, the adhesion strength and the corrosion resistance were excellent.

Claims (13)

(A) at least one selected from the group consisting of magnesite, mild magnesia and calcined magnesia; Method for producing a repair material raw material for steel or steelmaking equipment comprising the step of firing or melting one or more minerals selected from the following (B) and (C): (B): at least one mineral selected from the group consisting of olivine, serpentine, talc and fluorite; (C) one or more minerals selected from the group consisting of silica and silica sand. The method of claim 1, wherein the method (A) at least one selected from the group consisting of magnesite, mild magnesia and calcined magnesia; Grinding and mixing one or more minerals selected from (B) and (C); Shaping and drying the mixed and ground products; And Method for producing a repair material raw material for steel or steelmaking equipment comprising the step of firing the dried molding. The method of claim 1, wherein the method (A) at least one selected from the group consisting of magnesite, mild magnesia and calcined magnesia; Grinding and mixing one or more minerals selected from (B) and (C); And Method for producing a repair material raw material for steel or steelmaking equipment comprising the step of melting the mixed and ground products. The method according to claim 2 or 3, The pulverizing and mixing step is characterized in that the material is carried out by measuring the material so that the final magnesia content of the raw material is 50 to 80% by weight. The method according to claim 4, The pulverizing and mixing step is characterized in that the material is carried out by measuring the material so that the final magnesia content of the raw material to be manufactured 60 to 70% by weight. The method according to claim 1, The prepared repair material is forsterite is the main mineral phase, Pericles is a negative mineral phase manufacturing method of the repair material raw material characterized in that. The method according to claim 1 or 2, The firing is a repair material raw material manufacturing method characterized in that carried out at a temperature of 1500 ~ 1800 ℃. The method according to claim 1 or 3, The melting method for producing a repair material, characterized in that carried out at a temperature of 1850 ~ 2200 ℃. The raw material for repair materials of steelmaking or steelmaking facilities manufactured by the manufacturing method according to any one of claims 1 to 3. The repairing material of steelmaking or steelmaking facilities which further contains the repairing material raw material of any one of Claims 1-3, and optionally magnesia. The method according to claim 10, The repair material further comprises a silicic acid-based binder or a phosphoric acid-based binder. The method according to claim 10, The steelmaking or steelmaking equipment is any one selected from the group consisting of an electric furnace, converter, ladle, RH immersion pipe and tundish. The method according to claim 10, The repair material is a repair material, characterized in that the spray material or a coating material.