KR20110069219A - A slag deoxidizer, and an apparatus and method for manufacturing thereof - Google Patents

Abstract

PURPOSE: A slag deoxidizer, device and method for manufacturing the same are provided to prevent the occurrence of harmful dust and white smoke when being put into a ladle and enhance the cleanliness of ingot steel. CONSTITUTION: A slag deoxidizer separates and removes oxygen from slag after refining. The slag deoxidizer consists of 93~95weight% of Al, 2.5weight% or less of Fe, and inevitable impurities. The weight of the slag deoxidizer is 3~5g and is cast in a conical shape. The specific gravity of the slag deoxidizer is 2.7~2.8. The conical deoxidizer melts aluminium scraps in an aluminium melting reverberatory furnace an then is cast in a molten-metal distributor(3) and a continuous caster. The molten-metal distributor comprises 4~5mm diameter of a nozzle. The continuous caster has a moving speed of 1.0~2.0m/sec.

Description

Slag deoxidizer, manufacturing apparatus and manufacturing method therefor {A slag deoxidizer, and an apparatus and method for manufacturing}

The present invention relates to a slag deoxidizer used immediately after the converter refining or immediately after the completion of the RH refining, and more specifically, an Al molten distributor having a nozzle having a diameter of 4 to 5 mm after dissolving aluminum scrap using an aluminum melting reflector and 1.0 to Conical pellet type aluminum deoxidizer of 3 ~ 5g in weight manufactured using a continuous casting machine having a moving speed of 2.0m / sec, Al: 93 ~ 95%, Fe: 2.5% or less The present invention relates to a slag deoxidizer composed of the remaining other unavoidable impurities, a manufacturing apparatus thereof, and a manufacturing method thereof.

In general, when refining ultra-low carbon steel in a molten steel manufacturing process centered on a converter, a refining method for shortening cleanness and RH refining time of molten steel by injecting a solid slag deoxidizer into the ladle slag immediately after the converter goes out and immediately after the completion of RH vacuum degassing. I'm using For this deoxidation operation, it is common to add a metal having excellent affinity with oxygen, and aluminum is mainly used as a metal deoxidizer for this purpose. This series of operations is called deoxidation and it is divided into molten steel deoxidation and slag deoxidation depending on the deoxidation target.

In addition, there are methods of deoxidizing molten steel and slag at the same time and deoxidizing only slag according to the deoxidation method, and deoxidizers for molten steel include Al, Fe-Si, Fe-Mn, and in the case of slag deoxidizer, Korea patent is registered. Iron oxide (hereinafter referred to as FeO) and manganese oxide (hereinafter referred to as MnO) contained in 20 to 30% by weight of ladle slag such as 10-0847051, Patent 1999-0042920, Patent 1997-0004987, Patent 1999-000467, and Patent 1999-003067 It has been proposed a composition of slag deoxidizer and a method for reducing lower oxides.

However, the slag deoxidizers can be made of quicklime or limestone and inorganic binders (liquid sodium silicate, molasses, cement, benzo) in metallic aluminum (powdered, canned chips) or metallic aluminum separated from dross after melting aluminum. It is not only complex but also complicated in the manufacturing process, and the reaction between the aluminum dross and the inorganic binder. Ammonia gas is generated and working environment is very poor.

In addition, the components of these slag deoxidizers are slag deoxidizers in the range of at least 15 to 60% by weight of aluminum (AL), and when these slag deoxidizers are added to the ladle slag, lower oxides of the slag, that is, FeO, MnO, etc. It can be reduced to achieve the desired purpose, but since the raw materials (limestone and Al dross) and chips (Size 2mm or less) have been molded and dried, they are transported and stored in the hopper or put into the ladle at the discharge port of the feeding device. Since a large amount of harmful fugitive dust is generated and limestone and aluminum dross react with molten steel to generate flame and white smoke, not only workability is bad but also polluting the environment.

In order to solve this problem, aluminum scrap cans are cut to a certain size and heated to burn organic substances or paints on the surface, and then crushed products or aluminum wires manufactured using extruders to a certain size. Although cut and used, this type of product is not only complicated and inexpensive to manufacture, but also has a unit weight of between 0.5 and 2 g and is too light and has a low specific gravity that does not penetrate into the solidified ladle slag layer. Accordingly, the reaction efficiency of the slag deoxidizer is lowered because it reacts with oxygen in the air rather than reacting with iron oxide or manganese oxide in the ladle slag. On the other hand, if the weight is 6g or more, the aluminum injected to deoxidize the slag layer passes through the slag layer to reach the molten steel, and the aluminum content in the molten steel is not only increased, but the supersaturated aluminum in the molten steel and the slag containing lower oxide such as FeO and As a reaction of the following reaction formula 1, there is a problem in that the alumina to inhibit the molten steel in the molten steel is produced in the molten steel to make the cleanliness of the molten steel poor.

(Scheme 1) 3FeO + 2Al-> Al ₂ O ₃ + 3Fe

As described above, the problem of the deoxidizer due to mechanical molding may be somewhat solved is the deoxidizer manufactured by the casting method. Hereinafter, a deoxidizer and a method of manufacturing the same according to the prior art will be described.

1 is an example of a deoxidizer by a casting method disclosed in Korean Patent No. 10-0586403 and a manufacturing method thereof, and FIG. 1 shows an outline of a deoxidizer manufacturing apparatus according to the prior art. Although the present invention is somewhat different from the present invention in that it is for producing an aluminum deoxidizer containing iron pieces, it will be referred to only for casting deoxidizer.

As shown in FIG. 1, the present invention provides a mold transfer conveyor 22 in the injection nozzle 32 of the injection part 33 in a state in which a mold conveying conveyor 22 is transported with a mold (not shown). Molten aluminum is injected into the groove of each mold passing downward.

In addition, the iron reinforcing element transferred to one end of the reinforcing element conveying conveyor 51 of the iron reinforcing element injecting unit 55 in each mold is introduced into the groove of the mold, the injection portion 33 and the iron piece reinforcing element injecting unit ( The mold after 55) is transferred forward while cooling at room temperature continuously after the injection of molten aluminum and the input of the steel reinforcing element are finished.

As such, when the molten iron composite deoxidizer is moved forward in the cooled state, the cooling water is injected from the injection pipe 61 of the cooling unit 66, and the iron composite deoxidizer in the normal temperature cooling state is quenched. As the mold is cooled and transferred forward through the cooling unit 66, the edge of the mold is repeatedly charged by the price unit 88, and the mold and the iron strip composite deoxidizer are lifted, thereby allowing the iron strip composite deoxidizer to be separated from the mold. do. As the iron composite deoxidizer continues to move forward in the state separated from the mold, the mold is returned to the return point.

However, various problems have arisen in the conventional deoxidizer casting method as described above.

First, it is difficult to determine the amount of molten aluminum injected from the injection nozzle of the injection unit to an appropriate amount, and there is a hassle of determining and fixing the proper amount through several measurement processes. Therefore, in order to change the size of the cast deoxidizer, there is a problem that it is not easy to control the size of the deoxidizer because it is necessary to find a proper amount of aluminum to be injected again through new trial and error.

Second, the composite deoxidizer is a metal piece having a higher specific gravity and higher melting point than aluminum in the aluminum base, and is intended to replace the conventional aluminum molten steel deoxidizer for deoxidizing molten steel during the steelmaking process.

Therefore, in order to manufacture and utilize a deoxidizer that can only act in the slag layer of molten steel as in the present invention, it is necessary to develop a deoxidizer which can stay together in the slag layer for a long time, but there is no such concept of development. The reality is that no deoxidizer with similar specific gravity and conditions has been provided.

The present invention has been made to solve the problems of the prior art as described above, the concentration of the lower oxide which is a pollution source of molten steel, such as FeO and MnO present in the high melting steelmaking slag flowing into the ladle after the tapping in the converter. In providing a ladle slag deoxidizer which can be reduced to increase the cleanliness of molten steel, an object of the present invention is to provide a deoxidizer that can act intensively only in the slag layer on the upper part of the molten steel.

In addition, the present invention for this purpose is to provide a deoxidizer having a specific gravity and conditions similar to the slag layer, and an apparatus and a manufacturing method thereof.

In addition, unlike the deoxidizer by the conventional mechanical molding, the deoxidizer by the new casting method, which is more workable than the conventional casting method and works more effectively in the slag layer, without generating harmful fugitive dust and white smoke during ladle injection. It aims to provide.

In order to achieve the above object, the ladle slag deoxidizer of the present invention is a deoxidizer for separating and removing oxygen from slag after steelmaking refining, and the weight percent does not include Al: 93 to 95% and Fe: 2.5% or less (“0”). And other remaining unavoidable impurities, and cast into a conical shape with a weight of 3-5g, specific gravity of 2.7 ~ 2.8.

In addition, the conical deoxidizer of the present invention, after dissolving the aluminum scrap in the aluminum melting reflector, characterized in that continuously cast in a molten metal distributor having a nozzle size of 4 ~ 5mm and a continuous casting machine having a moving speed of 1.0 ~ 2.0m / sec It is done.

In addition, the slag deoxidizer manufacturing apparatus of the present invention, in the deoxidizer manufacturing apparatus comprising an aluminum molten reflector, a melt runner, a melt distributor and a speed control motor, characterized in that the melt distributor is characterized in that the nozzle diameter is 4 ~ 5mm. .

In addition, the slag deoxidizer manufacturing method of the present invention is a deoxidizer manufacturing method for separating and removing oxygen from slag after steelmaking, solid aluminum is added to a molten reflector and heated to a weight% of Al: 93 to 95%, Fe: 2.5 Preparing an aluminum molten metal formed of no more than% (not including "0") and the remaining other unavoidable impurities; Introducing the molten aluminum into a molten distributor having a nozzle diameter of 4 to 5 mm via a molten runner; Injecting molten metal introduced into the molten metal into a mold through a nozzle; And separating the cooled and cured deoxidizer from the mold in the mold.

As described above, the present invention reduces the concentration of lower oxides, which are contaminants of molten steel, such as FeO and MnO, present in the high melting steelmaking slag introduced into the ladle after tapping into the ladle in the converter to improve cleanliness of the molten steel. Provide slag deoxidizer. In particular, it is possible to provide a deoxidizer which can only act intensively in the slag layer on top of the molten steel.

Accordingly, the present invention provides a deoxidizer having a specific gravity and conditions similar to those of a slag layer, a manufacturing apparatus thereof, and a manufacturing method thereof.

In addition, unlike the deoxidizer by the conventional mechanical molding, the deoxidizer by the new casting method, which is more workable than the conventional casting method and works more effectively in the slag layer, without generating harmful fugitive dust and white smoke during ladle injection. to provide.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

3 is a schematic view of a slag deoxidizer production apparatus according to the present invention. The slag deoxidizer production apparatus of the present invention comprises an aluminum molten reflection furnace, a melt runner, a melt distributor and a speed control motor.

In order to manufacture the slag deoxidizer according to the present invention, solid aluminum such as can scrap and aluminum scrap is first introduced into the aluminum melting reflection furnace 1, and then heated and melted above the melting point. The molten aluminum is weighed to have a chemical composition of Al: 93-95%, Fe: 2.5% or less (does not contain "0") and the rest of the unavoidable impurities in weight% to control the input ratio.

The aluminum molten metal extracted from the molten reflection furnace 1 is transferred to the molten metal distributor 3 through the molten runner 2, and the molten metal introduced into the mold 4 through the nozzle of the molten metal distributor 3 is preliminarily introduced into the mold. It solidifies to a certain shape according to the formed shape. In the present invention, as shown in Fig. 2, solidification into a cone is recommended. According to the nozzle size of the molten metal distributor 3, the emission of aluminum molten metal is changed, and thus the weight of the deoxidizer finished product is determined.

4 is a schematic diagram of a melt distributor used in the present invention. A plurality of nozzles 7 are formed on the bottom of the molten metal distributor 3. In order to form deoxidizers with slag-like conditions, the diameter size of the nozzle should be 4-5mm. This is an important factor in forming the conditions of deoxidizer which acts intensively on slag such as the size, weight, specific gravity of deoxidizer, etc. together with the speed of continuous casting to be similar to molten steel slag. If the diameter size of the nozzle is less than 4mm or more than 5mm, the deoxidizer having a weight of 3-5g in the continuous casting machine having a moving speed of casting speed of 1.0 ~ 2.0 m / sec can not be produced due to physical constraints.

A plurality of molds 4 are placed on the conveyor belt 6 below the molten metal distributor 3. The moving speed of the conveyor belt 6 is controlled by the speed regulating motor 5 at a casting speed of 1.0 to 2.0 m / sec. Each mold 4 has a plurality of molten metal accommodating parts. Melt receivers are usually paired and arranged with the nozzles of the upper melt dispenser but are not required to mate. The shape of the molten metal receiving part may be provided in various forms, but in the present invention, it is recommended to cast the inverted line cone. Therefore, when the deoxidizer is cast and becomes a finished product, the shape of the natural deoxidizer has a conical shape.

The reason for casting the deoxidizer into conical shape is that the conical deoxidizers are not interviewed with each other when they are introduced into the molten steel slag through the hopper in the future, so that they can be easily separated and the contact surfaces are reduced even inside the molten steel slag to prevent tangling. Because you can.

When the molten aluminum is solidified in the mold 4 to form a deoxidizing agent, after cooling, the deoxidizing agent is separated from the mold and blows hard on one side of the mold 4 so that it can easily come out. The deoxidant separated by the reverse process is reversed while the conveyor belt 6 proceeds downward and is collected by collecting the conveyor belt 6 below.

The weight of the slag deoxidizer thus prepared is adjusted to have 3 to 5g. If the weight of the slag deoxidizer is less than 3g, the deoxidizer cannot rest on the slag layer and deoxidizes.If the weight of the slag deoxidizer is more than 5g, the deoxidizer penetrates the slag layer under its load and gravity at the It causes a problem of changing the purity of molten steel.

Hereinafter, the change of the unit weight of the deoxidizer according to the change in the unit weight of the deoxidizer and the playing speed according to the nozzle diameter, which is a key part of the present invention, will be described in more detail.

Table 1 shows the change in the unit weight of the deoxidizer (Al-SHOT) according to the nozzle diameter measured by the experiment. [table. As can be seen from 1], when the size of the nozzle diameter is larger than 5mm, the unit weight increases steeply. When the nozzle size is less than 3.5mm, the unit weight is not only small but also the nozzle clogging occurs frequently. Will occur.

[Table.1] Unit weight change according to nozzle diameter

Nozzle Diameter (mm) 3 3.5 4 4.5 5 5.5 Weight (g) 1.3 2.2 3.1 4.0 4.9 8.5

In addition, the size and weight of the deoxidizer may vary depending on the speed of the continuous casting mold.

Table 2 shows the weight change of the deoxidizer according to the playing mold speed.

The slower the playing speed, the higher the unit weight. At speeds of 2.5m / sec or more, it contributed to product shape and underweight in the manufacturing process.

Table 2

Playing speed (m / sec) 0.3 0.5 1.0 1.5 2.0 2.5 Weight (g) 12.1 7.3 4.9 3.8 3.1 2.1

As can be seen from above, in order to manufacture a deoxidizer with an appropriate weight of 3 to 5 g and a specific gravity of 2.7 to 2.8, which can be used as a ladle slag deoxidizer in the steelmaking process, the nozzle diameter of the distributor must be within the range of 4 to 5 mm, and the playing mold The speed should be 1.0 ~ 2.0m / sec.

As described above, the aluminum scrap is directly melted and continuously cast by using a reflection furnace, so that the Sol.Al is 93 to 95%, the T.Fe is 2.5% or less, and the remainder is a slag deoxidizer having a weight of 3 to 5 g or less. The production method is not only very economical compared to the conventional method, but also an effective and unique method that can improve productivity and quality by intensively deoxidizing slag.

The deoxidizer produced by the present invention (AL-SHOT) can be expected to improve the slag deoxidation effect up to 120% compared to the conventional slag deoxidizer, the slag deoxidizer field used in the steelmaking process does not occur scattering dust and flames during the injection Is a very useful invention.

Hereinafter, the present invention will be described in more detail with reference to Examples. These examples are only for illustrating the present invention in more detail, it will be apparent to those skilled in the art that the scope of the present invention is not limited by these examples in accordance with the gist of the present invention. .

≪ Example 1 >

Next, the results of experiments on the slag deoxidation effect for the present invention are shown in [Table 3]. The experiment was carried out in a 100ton class converter (LD-Converter), and the contents of lower oxides (T. Fe and MnO) in slag were changed according to the amount of slag deoxidizer added to the slag deoxidant by ladle slag after the slab was applied to the same steel. The results obtained by luminescence analysis are shown.

[Table 3]

Before input Existing Material 1 Existing Material 2 Invention Ingredients (AL%) AL 35% AL65% AL93% Input amount (KG) 200 150 70 Lower oxide weight% 20-30 8-10 3-5 <3 Dust and white smoke O O X

As can be seen from Table 3, quicklime or limestone and inorganic binder (liquid sodium silicate) in metallic aluminum (powdered, can-broken chips) or metallic aluminum separated from dross generated after aluminum dissolution. , Molasses, cement, benzoite), etc., in comparison with the existing materials 1 and 2, which have undergone molding and drying after mixing in an appropriate ratio, in the case of the present invention, the maximum amount of 35 to 50% of the existing materials A 60% improvement was achieved, and there was little generation of harmful fugitive dust and white lead at the time of injection.

1 is a schematic diagram of an iron piece composite deoxidizer production apparatus according to the prior art.

Figure 2 is a photograph showing the shape of the slag deoxidizer of the present invention.

3 is a schematic view of a slag deoxidizer production apparatus according to the present invention.

4 is a front cross-sectional view and a plan view of the melt dispenser of the present invention.

♣ Explanation of symbols for main part of drawing ♣

DESCRIPTION OF SYMBOLS 1: Melting reflection furnace 2: Melt runner 3: Melt distributor 4: Mold

5: motor 6: conveyor belt 7: nozzle

22: mold transfer conveyor 32: injection nozzle 33: injection unit

51 reinforcement element conveying conveyor 55 input unit 61 injection pipe

66: cooling unit 88: price unit

Claims (4)

In the deoxidizer which separates and removes oxygen from slag after steelmaking refining, By weight% Al: 93-95%, Fe: 2.5% or less (does not contain "0") and the rest of other unavoidable impurities, cast into cone shape of 3 ~ 5g weight, specific gravity of 2.7 ~ 2.8 Slag deoxidizer, characterized in that The method according to claim 1, The conical deoxidizer is a slag deoxidizer, characterized in that the molten aluminum scrap in the aluminum melting reflector after continuous casting in a molten distributor having a nozzle size of 4 ~ 5mm diameter and a continuous casting machine having a moving speed of 1.0 ~ 2.0m / sec In the deoxidizer manufacturing apparatus comprising an aluminum molten reflection furnace, a melt runner, a melt distributor and a speed control motor, The molten metal distributor is a slag deoxidizer manufacturing apparatus, characterized in that the nozzle diameter is 4 ~ 5mm In the manufacturing method of the deoxidizer for separating and removing oxygen from the slag after steelmaking refining, Preparing aluminum molten metal formed of Al: 93-95%, Fe: 2.5% or less (not including "0") and the remaining other unavoidable impurities by weight by adding solid aluminum to a melting reflector; Introducing the molten aluminum into a molten distributor having a nozzle diameter of 4 to 5 mm via a molten runner; Injecting molten metal introduced into the molten metal into a mold through a nozzle; Method for producing a slag deoxidizer characterized in that it comprises the step of separating the cooled, hardened deoxidizer from the mold in the mold.

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