KR101040554B1 - Steel refinery flux and manufacturing method thereof - Google Patents

Abstract

PURPOSE: Steel refinery flux and a preparation method thereof are provided to improve the efficiency of work using the flux because no dust is generated from the flux put in molten metal and the components of the flux uniformly react in molten metal. CONSTITUTION: A method of preparing steel refinery flux(10) comprises steps of: crushing limestone to the size less than 20mm, plasticizing the crushed limestone at 880~980°C to obtain granular quicklime(12) of 5~20mm, collecting and crushing aluminum dross generating in refinement of aluminum, adding a binder to the crushed aluminum dross to obtain granular aluminum(11) of 5~20mm, and mixing the granular aluminum and the granular quicklime at the weight ratio of 4:6~6:4.

Description

Steelmaking flux and its manufacturing method {STEEL REFINERY FLUX AND MANUFACTURING METHOD THEREOF}

The present invention relates to a steelmaking flux that is introduced into a molten metal to form a slag layer to prevent the surface of the molten metal from contacting the atmosphere, and more particularly, a slag layer is formed in the molten metal within a short time. The present invention relates to a steelmaking flux which can be injected (injected) by using an input device and quickly and easily form a basicity of a desired slag, and a method of manufacturing the same.

In general, steel produced in an electric furnace is deteriorated due to non-metallic inclusions, such as oxygen, sulfur, and phosphorus, and thus, impurities must be removed during the steel manufacturing process. In addition, since the molten metal is oxidized in contact with the oxygen in the atmosphere and the quality of the steel may be degraded, the surface of the molten metal should be prevented from contacting the atmosphere.

To this end, flux is injected to the surface of the molten metal during steel production. The flux is applied to cover the parts in contact with the gas and the atmosphere in the furnace so as not to directly contact the melt and the gas and the atmosphere in the furnace. In addition, the introduced flux may play a role of improving the quality of the steel, such as removing impurities in the molten metal and preventing the absorption of carbon from the electrode.

Steelmaking flux may mainly comprise fluorite (CaF ₂ ), quicklime (CaO), Al ₂ O ₃ , SiO ₂ and the like. However, the use of fluorspar (CaF ₂ ) has a disadvantage that the refractory can be eroded by the high acidity, it may be advantageous to use quicklime (CaO). Quicklime prevents heat dissipation of the molten surface and can perform dephosphorization and desulfurization.

In addition, Al ₂ O ₃ can be obtained from aluminum dross generated in the aluminum refining process. In general, aluminum dross is used by pulverizing the dross generated in the refining process, so its shape may be irregular and the reactivity may be uneven when it is added into the molten metal. In addition, since the particle size and shape is uneven and there is a large amount of fine particles in powder form, when it is added to the molten metal is scattered and lost in the form of dust and agglomerates on the surface of the molten metal.

The present invention is to provide a steelmaking flux that can react uniformly in the molten metal when dust is not generated when it is added to the molten metal and a method of manufacturing the same.

In addition, the present invention is to provide a steelmaking flux and a method for manufacturing the same, which can be injected into the automatic injection device when the molten metal is injected and the slag layer is formed in the molten metal within a short time, thereby shortening the operation time.

Steelmaking flux according to an embodiment of the present invention for realizing the above problems, the granular aluminum and granular quicklime produced by adding a binder to the aluminum dross generated during smelting of aluminum in a weight ratio of 4: 6 to 6: 4 Can be mixed.

The particle size of the granular aluminum may be 5 to 20mm.

The particles having a particle size of 5 to 20 mm may be 85% or more of the total weight of the granular aluminum.

The granular quicklime may have a particle size of 5 to 20 mm.

The particles having a particle size of 5 to 20 mm may be 85% or more of the total weight of the granular quicklime.

According to an aspect of the present invention, there is provided a method of manufacturing a flux for steelmaking, comprising: crushing limestone to a size of 20 mm or less, and calcining the crushed limestone at 880 to 980 ° C. for 5 to 20 mm. Preparing granular calcined circuits, collecting and pulverizing aluminum dross generated during smelting aluminum, and adding a binder to the pulverized aluminum dross to produce granular aluminum of 5 to 20 mm, and the granular aluminum Mixing the agent and the granular quicklime in a weight ratio of 4: 6 to 6: 4.

In the step of collecting and grinding the aluminum dross, a plurality of aluminum dross are collected and mixed such that the Al ₂ O ₃ content of the aluminum dross is 5: 5 in a weight ratio of CaO included in the quicklime. It may further comprise the step of grinding.

According to the steelmaking flux and the manufacturing method according to the present invention configured as described above, dust is not generated when introduced into the molten metal, the flux input efficiency is increased and the working environment is improved, and the components of the flux in the molten metal They react uniformly with each other to improve the work efficiency. In addition, it is possible to inject (inject) using a feeder to form a slag layer in a short time, shorten the operating time, increase the recovery rate of expensive metals (Mn, Cr, Ni, Mo, V, etc.) and improve the basicity of slag Easy to fit quickly and easily

1 is a photograph of a steelmaking flux according to an embodiment of the present invention.
2 is a flow chart schematically showing a method of manufacturing a steelmaking flux according to an embodiment of the present invention.
3A is a schematic diagram of a steelmaking flux injector for explaining a state of use of the steelmaking flux according to an embodiment of the present invention.
3B is a schematic diagram of a steelmaking flux injector for explaining a state of use of the steelmaking flux according to an embodiment of the present invention.

Hereinafter, a steelmaking flux according to a preferred embodiment of the present invention and a manufacturing method thereof will be described in detail with reference to the accompanying drawings. In the present specification, the same or similar reference numerals are assigned to the same or similar configurations in different embodiments, and the description thereof is replaced with the first description.

1 is a photograph of a steelmaking flux according to an embodiment of the present invention.

Referring to this drawing, the steelmaking flux 10 according to an embodiment of the present invention may be manufactured in a form in which granular aluminum 11 and granular quicklime 12 are mixed.

The granular aluminum 11 and the quicklime quicklime 12 may be formed in a mixture in a weight ratio of 4: 6 to 6: 4.

The granular aluminum 11 may be made of aluminum dross produced during aluminum smelting. The aluminum dross is obtained in an aluminum refining process, and the aluminum dross may include a large amount of Al ₂ O ₃ and some metals Al, SiO ₂ , and the like. The granular aluminum 11 can be made of a powder obtained by collecting and grinding such aluminum dross. The granular aluminum 11 may be manufactured by mixing a plurality of aluminum dross and collecting the Al ₂ O ₃ until a predetermined amount or more is pulverized. Granular aluminum 11 may be prepared by adding a binder to the powder of crushed aluminum dross. Specifically, the granular aluminum 11 may be prepared by granulating by mixing binders such as water glass or molasses with the aluminum dross powder collected and pulverized. Water glass and molasses used in the manufacture of the granular aluminum 11 may be used alone, or both may be used.

Granular aluminum (11) is possible in a variety of forms, but is preferably produced in a spherical shape so as to have the largest reaction surface area when added to the molten metal. The particle size of the granular aluminum 11 is preferably 5 mm or more and 20 mm or less. More preferably, the proportion of particles having a particle size of 5 mm or more and 20 mm or less is preferably 85% or more relative to the total weight of the granular aluminum 11. If the particle size is less than 5mm, it may be scattered in the furnace like powder, so it may not be injected into the molten metal.If the particle size exceeds 20mm, injection by using the injector may be blocked by blocking the passage of the injector, and it may be rapidly removed from the surface of the melt. It may not melt, which may lower the oxidation prevention efficiency of the molten metal. If the particle size is 5mm or more and 20mm or less, it may be easy to pass through a hopper or feeder for introducing the steelmaking flux 10 into the electric furnace.

The granular aluminum 11 may be sprayed onto the surface of the molten metal by a hopper or an injector, and the granular aluminum 11 may quickly react with the molten metal while being in contact with the surface of the molten metal. The metal Al contained in the granular aluminum 11 causes deoxidation in the molten metal, wherein the alumina deposit forms slag and covers the surface of the molten metal so that the molten surface, the gas in the furnace, and the atmosphere contact the molten surface. Will be prevented.

The granular quicklime 12 can be produced using limestone as a raw material. The granular quicklime 12 can be in various forms but can be generally amorphous. The granular quicklime 12 may have a particle size of 5 mm or more and 20 mm or less. That is, the granular quicklime 12 and the granular aluminum 11 may have the same particle size range. It is preferable that the particle size of the granular quicklime 12 is 5 mm or more and 20 mm or less, more than 85% of the total weight of the granular quicklime 12. If the granular quicklime 12 is less than 5 mm, it is scattered in the form of dust in the furnace, which is not only environmentally harmful, but also increases the rate at which it cannot be introduced into the molten metal. In addition, when the particle size of the granular quicklime 12 is more than 20 mm, the melting speed is slow when it is added to the molten metal surface, the slag formation may be delayed and work efficiency may be reduced. In addition, the weight ratio of quicklime is high when the feed tube is clogged, so it cannot be inserted into the automatic feeding device. If the particles having a particle size of 5 mm or more and 20 mm or less are 85% or more of the total weight, the fine particles generated during the grinding of the granular aluminum and the quicklime quicklime may adhere to the large particles and the scattering may be suppressed. Particles are separated and scattered from large particles, which may cause problems such as particle loss and working environment pollution. That is, when 15% or more of fine powder of less than 5mm is formed in the manufacturing process of granular quicklime and granular aluminum dross, the degree of scattering is strong in the furnace, which makes it difficult to efficiently enter the molten metal.

CaO, a component of the granular quicklime 12, is combined with sulfur in the molten metal,

CaO + S → CaS + O

Reaction may contribute to the adjustment of slag basicity, desulfurization and denitrification.

2 is a flow chart schematically showing a method of manufacturing a steelmaking flux according to an embodiment of the present invention. The manufacturing method of the steelmaking flux 10 according to the embodiment of the present invention will be described with reference to the drawings.

First, in order to manufacture the granular quicklime 12, the limestone which is a raw material of the granular quicklime 12 is crushed to a size of 20 mm or less (S10). At this time, if the limestone is less than 20mm it is also possible to use immediately without crushing.

Limestone crushed to the size of 20mm or less is calcined to produce a quicklime (S20). In the calcining operation of limestone, the limestone charged in the rotating heater body can be heated by a burner and preheated using exhaust gas. While the limestone filled in the preheater continuously descends by gravity, the gemstone may be preheated by the heat gas discharged from the main body and then moved to the main body and fired. At this time, the temperature for firing the crushed limestone is preferably 880 ~ 980 ℃.

Aluminum dross generated during aluminum smelting is collected, and the collected aluminum dross is prepared by grinding (S30). The aluminum dross is composed of metal aluminum, aluminum oxide, aluminum nitride, and the like, although the composition varies depending on the source. When aluminum dross reacts with water, it violently hydrolyzes, causing an increase in temperature and gas. At this time, the exothermic reaction may go up to 200 degrees Celsius. For this reason, aluminum dross produced during smelting of aluminum is a very dangerous material for handling and landfilling. Therefore, the aluminum dross can be used to reduce the risk of environmental pollution and handling by recycling the antioxidant and deoxidizer during steelmaking.

Aluminum dross is divided into white dross having an aluminum content of 15 to 80% and black dross containing a large amount of chloride and aluminum about 7 to 15%. The aluminum dross may use one of white dross and black dross, or both. When the content of Al ₂ O ₃ in the steelmaking flux 10 is lower than the content of CaO, the content of aluminum in the slag is lowered, thereby lowering the slag formation efficiency and lowering the oxidation prevention efficiency of the molten steel. In addition, when the content of Al ₂ O ₃ is higher than the content of CaO, the phosphorus that should be contained in the slag is formed because excess metal aluminum separates oxygen from phosphorus and then combines with oxygen separated from phosphorus to form an oxide. A compounding phenomenon may be brought back from slag to molten steel.

Collecting and grinding the aluminum dross may include collecting a plurality of aluminum dross such that the Al ₂ O ₃ content included in the aluminum dross has a CaO content in the weight ratio of about 5: 5 in weight ratio. do. More preferably, the Al ₂ O ₃ content included in the aluminum dross is adjusted to be 5: 5 by weight ratio of CaO included in the quicklime. The aluminum dross collected in this way can be pulverized with a grinder or the like. Aluminum dross can be ground to have particles of at least 0.2 mm. Aluminum dross is preferably ground to have particles of less than 1 mm, taking into account the size of the final product.

A binder may be added to the pulverized aluminum dross to prepare a granular aluminum 11 of 5 to 20 mm (S40). A binder (binder) may be added to the pulverized aluminum dross powder using a pulverizer or the like.

As the binder, known molasses (starch), water glass, or the like can be used. A binder can be used 1 type or in mixture of 2 or more types.

The granular aluminum 11 is manufactured by adding a binder to the aluminum dross powder, wherein the size of the granular aluminum 11 finally prepared is preferably 5 to 20 mm in diameter based on a spherical shape. The shape of the granular aluminum 11 may be any shape, but is preferably spherical in order to maximize the surface area reacting with the molten metal and to react uniformly.

After the preparation of the granular quicklime 12 and the granular aluminum 11 is completed, the two steel materials may be mixed in a ratio of 4: 6 to 6: 4 in weight ratio to produce the steelmaking flux 10 (S50). In order to prevent oxidation of the molten metal by rapidly forming initial slag after the molten steel is manufactured, it is important to rapidly react by injecting the steelmaking flux 10. When the ratio of the granular quicklime 12 and the granular aluminum 11 is 4: 6 to 6: 4, the reaction with the molten metal occurs quickly and the oxidation prevention efficiency of the molten metal is good.

The reason for mixing the steelmaking flux 10 in two ratios (granular quicklime 12 and granular aluminum 11) in a weight ratio of 4: 6 to 6: 4 is to quickly and easily dissolve in the molten metal. .

In the binary system of Al ₂ O ₃ and CaO, which are the main components of the steelmaking flux, the melting point is the lowest when the ratio is 5: 5. When the quicklime or aluminum dross are added alone to each other with time difference for slag formation, the melting point is difficult to occur due to compounding. As a result, the temperature of the melt is lowered because the respective flux components are not easily dissolved. As a result, higher calories are required to dissolve the components of the flux, which may cause an increase in the power ratio.

On the other hand, when the granular quicklime 12 and the granular aluminum 11 are added at the same time, the melting point of the flux injected by reacting each other with Al ₂ O ₃ and CaO, which are the main components of the granular quicklime and granular aluminum, is reduced. As a result, there is an advantage that the cooling of the molten metal can be easily and quickly dissolved in the steelmaking flux 10.

3A to 3B are schematic diagrams of a steelmaking flux injector for explaining a state of use of the steelmaking flux according to an embodiment of the present invention.

Steelmaking flux 10 formed as shown in the drawing may be injected into the electric furnace 200 or LF (Ladle Furnace, 300) by the injector 100. Specifically, the steelmaking flux 10 is accommodated in the reservoir 110 constituting the injector 100 and then discharged to the outside through the discharger 120. The discharged steelmaking flux 10 is moved to the hopper 400 through the injection pipe 140 by the air pressure generated by the air pump 130. The steelmaking flux 10 moved to the hopper 400 by the injector 100 is introduced into the electric furnace 200 or the LF 300 through the hopper 400. The diameter of the injection tube 140 through which the steelmaking flux 10 passes is generally about 50 mm. Thus, in order to smoothly inject the steelmaking flux 10 according to the embodiment of the present invention, the granular aluminum 11 and the granular quicklime 12 preferably have a diameter of 5 to 20 mm. When the particle size of the steelmaking flux 10 is less than 5 mm, the amount of the steelmaking flux 10 that is lost, such as being blown up while being blown upward by the air pressure generated by the air pump 130 and attached to the injection tube 140, is lost. There can be a lot of drawbacks. In addition, when it exceeds 20mm, the weight of the steelmaking flux 10 becomes heavy, so that it is not easy to blow up to the upper by air pressure, and thus work efficiency may decrease, and a large amount of steelmaking flux 10 is injected into the injection tube ( When passing through 140 occurs in the injection tube 140 or the problem that does not transfer to block the injection tube (140).

According to the steelmaking flux and the manufacturing method according to the present invention configured as described above, dust is not generated when the electric furnace 200 or LF (300) injected into the molten metal, the working environment is improved, the recovery rate is increased and in the molten metal It is easy to dissolve in and reacts uniformly, thereby improving work efficiency. In addition, it is possible to smoothly inject through the injector 100, and to form a slag layer in a short time through rapid dissolution, it is effective to shorten the operating time, reduce the power ratio and quickly adjust the basicity of the slag.

Steelmaking flux as described above and a method of manufacturing the same is not limited to the configuration and operation of the embodiments described above. The above embodiments may be configured such that various modifications may be made by selectively combining all or part of the embodiments.

10: steelmaking flux 11: granular aluminum
12: granular quicklime 100: injector
110: reservoir 120: ejector
130: air pump 140: injection pipe
200: electric furnace 300: LF
400: Hopper

Claims (7)

Granular aluminum and granular quicklime prepared by adding a binder to aluminum dross generated during aluminum smelting are mixed in a weight ratio of 4: 6 to 6: 4, and the particle size of the granular aluminum is 5 to 20 mm, and the particle size is 5 to 20 mm. Phosphorus particles are 85% or more of the total weight of the granular aluminum, flux for steelmaking.
delete delete The method according to claim 1,
The grain size of the granular quicklime is 5 to 20mm, steelmaking flux.
The method according to claim 4,
The particles having a particle size of 5 to 20mm is 85% or more of the total weight of the granular quicklime, steelmaking flux.
Crushing limestone to a size of 20 mm or less;
Calcining the crushed limestone at 880-980 ° C. to produce a granular quicklime of 5 to 20 mm;
Collecting and grinding aluminum dross generated during smelting of aluminum;
Adding a binder to the pulverized aluminum dross to prepare a 5 to 20 mm granular aluminum; And
Mixing the granular aluminum and the granular quicklime in a weight ratio of 4: 6 to 6: 4; comprising, manufacturing steel flux.
The method of claim 6,
Collecting and grinding the aluminum dross,
Steelmaking flux further comprising the step of collecting, mixing and grinding a plurality of aluminum dross so that the Al ₂ O ₃ content contained in the aluminum dross is 5: 5 in a weight ratio and the content of CaO included in the quicklime Manufacturing method.

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