KR100782262B1 - Manufacturing method of flux for steelmaking with ladleslag - Google Patents

Abstract

A method of manufacturing steelmaking flux using ladle slag is provided to use steelmaking byproducts having a particle size of 5mm or less, thereby reducing manufacturing cost. A method of manufacturing steelmaking flux using ladle slag includes the steps of cooling ladle slag(10), crashing the cooled ladle slag(20), selecting the ladle slag having a particle size of 5mm or less(30), adding syrup to the selected ladle slag(40), adding CaO powder into the syrup-added ladle slag(50), manufacturing a monochromatic body using the syrup and CaO powder-added ladle slag(60), and curing the monochromatic body(70).

Description

 Manufacturing method of flux for steelmaking using ladle slag and manufacturing steel flux using same {Manufacturing method of flux for steelmaking with ladleslag}

1 is a flow chart of a steel manufacturing flux manufacturing method using a ladle slag according to an embodiment of the present invention.

The present invention relates to a steelmaking flux manufacturing method using a ladle slag, and to a steelmaking flux manufactured using the same, more specifically, by producing a steelmaking flux by efficiently recycling the ladle slag powder having a particle size of 5mm or less, conventional limestone Method of manufacturing flux for steelmaking using ladle slag to reduce production cost in steelmaking by using steelmaking by-products while preventing expansion collapse and dust generation of briquettes by using powder alone and steelmaking manufactured using the same It's about flux.

In general, the non-metallic inclusions (O, S, P, etc.) contained in the steel in the steelmaking process has a problem of lowering the properties of the steel, in particular, oxides and sulfides in the non-metallic inclusions greatly reduce the properties of the steel, such as electric furnaces and converters Flux is used to remove these impurities in the steelmaking process.

However, the conventional flux is prepared by crushing calcined limestone calcined limestone (CaO) and bauxite calcined bauxite at a suitable ratio, then calcined, melted and cooled, and then crushed and sorted to an appropriate particle size. The high price of flux is dependent on the total amount of income.

On the other hand, in order to solve the above problems, slag, that is, inexpensive flux using slag (Skull) also referred to as the solidified and fixed to the upper part of the ladle in the process of repairing and leaving the molten iron (Slag) Attempts have been made to manufacture. Representatively, Korean Patent Application Publication No. 10-2005-0084699 (name: flux replacement agent composed of mini mill refining slag) recovers refined slag that is excluded after refining in a refining furnace during the mini mill steelmaking process. The flux replacement agent composed of a mini mill refinement slag that can replace the steelmaking flux used in the electric furnace steelmaking process is proposed, but the mini mill refinement slag used in the flux substitute has a particle size of 5 to 50 mm among the mini mill refinement slag. As the use of the refined slag screening, refining slag with a particle size of 5mm or less had a problem that can not be utilized.

In addition, Korean Laid-Open Patent Publication No. 10-1997-0043121 (name: manufacturing method of flux for refining aluminum deoxidation steel using ladle slag), 20-40 parts by weight of limestone powder is mixed with 100 parts by weight of ladle slag, and this mixture Proposed a method for producing aluminum deoxidation steel refining flux using ladle slag which is formed into pellet or briquette, but when the limestone powder alone is used in the ladle slag, the strength of pellet or briquette is weak. The productivity of the molded product is reduced, and the amount of dust generated during handling of the molded product is not only detrimental to the working environment.In addition, when molding the ladle slag having a particle size of 5 mm or less into pellets, it is required to be molded by adding water. There was a problem such as excessively increased generation amount.

The present invention is to solve the above problems, in particular, the present invention by adding a quick lime (CaO) powder and molasses to the ladle slag powder having a particle size of 5mm or less and then briquette forming the flux for steelmaking, the conventional limestone powder Method of manufacturing flux for steelmaking using ladle slag to reduce production cost in steelmaking operations by using steelmaking by-products with a particle size of 5mm or less while preventing expansion and collapse of briquettes due to single use It is an object to provide a steelmaking flux.

Features of the present invention for achieving the above object, the cooling step 10 for cooling the ladle slag, the crushing step 20 for crushing the cooled ladle slag, and the particle size of 5 mm or less of the crushed ladle slag A sorting step 30 of selecting a ladle slag, a molasses adding step 40 of adding molasses to the selected ladle slag, and quicklime (CaO) of adding quicklime (CaO) powder to the ladle slag to which the molasses is added Ladle comprising a powder addition step 50, briquette forming step 60 for producing briquettes using a ladle slag to which the molasses and quicklime (CaO) powder is added, and curing step 70 for curing the briquettes Steelmaking plus manufacturing method using slag.

Another feature of the present invention for achieving the above object is a steelmaking flux produced by the above method.

The molasses addition step 40 according to the above characteristics of the present invention may constitute an embodiment in which 10 parts by weight to 15 parts by weight of molasses is added based on 100 parts by weight of the ladle slag of 5 mm or less.

In addition, the quicklime (CaO) powder addition step 50 according to the characteristics of the present invention, it can constitute an embodiment to add 0.5 parts by weight to 3 parts by weight of quicklime (CaO) powder with respect to 100 parts by weight of ladle slag 5mm or less. have.

In each of the above embodiments, 100 parts by weight of the ladle slag of 5 mm or less may constitute an embodiment containing 25 parts by weight or more of the ladle slag of 0.5 mm or less.

The objects, features and advantages of the present invention will be more readily understood by reference to the accompanying drawings and the following detailed description.

Hereinafter, with reference to the accompanying drawings will be described in detail the configuration and effect of the preferred embodiment of the present invention.

1 is a flow chart of a steelmaking flux manufacturing method using a ladle slag according to an embodiment of the present invention, the steelmaking flux using a ladle slag of the present invention cooling step (10), crushing step (20), and screening It is prepared through the step 30, molasses addition step 40, quicklime (CaO) powder addition step 50, briquette forming step 60, and curing step 70.

The cooling step 10 is a step of cooling the ladle slag, the ladle slag used the ladle slag generated in the secondary refining process of the steelmaking process of integrated steelworks, the cooling of the ladle slag is a slag of molten slag 500 The solution is quenched with water and cooled by air cooling thereafter.

Iron having magnetic properties in the ladle slag generated in the secondary refining process was removed through magnetic screening. The chemical composition of the ladle slag is shown in Table 1 below, and the physical properties thereof are shown in Table 2 below.

Table 1. Chemical Composition of Ladle Slag (Unit: wt%)

T-Fe CaO Al ₂ O ₃ SiO ₂ MgO MnO S 1 to 3 43 ~ 47 22-30 8-12 4 ~ 7 0.6 to 1.0 0.1-0.3

Table 2. Properties of Ladle Slag

Crystal phase composition Average particle diameter 12CaO · 7Al ₂ O ₃ [40 ~ 60%] 2CaO · SiO ₂ [30 ~ 50%] Others [10% or less] 21 μm

The crushing step 20 is to crush the cooled ladle slag,

The sorting step 30 is a step of sorting the ladle slag having a particle size of 5mm or less of the crushed ladle slag, 100 parts by weight of the ladle slag 5mm or less in the screening process so that the ladle slag of 0.5mm or less contains 25 parts by weight or more. It is desirable to.

The molasses adding step 40, as the step of adding molasses to the selected ladle slag, the molasses is most preferably added to the molasses 10 parts by weight to 15 parts by weight based on 100 parts by weight of the ladle slag 5mm or less,

The quicklime (CaO) powder addition step (50) is a step of adding quicklime (CaO) powder to the ladle slag to which the molasses is added, and the quicklime (CaO) powder has a particle size of 3000 cm 2 / g or more It is effective to use, and the amount of quicklime (CaO) powder is most preferably added 0.5 parts by weight to 3 parts by weight of quicklime (CaO) powder with respect to 100 parts by weight of ladle slag of 5 mm or less.

The briquette forming step 60 is a step of producing briquettes using a ladle slag to which molasses and quicklime (CaO) powder is added, and the curing step 70 is a step of curing the briquettes.

Hereinafter, a preferred addition amount of each of the additives is calculated through Comparative Examples and Examples for the steelmaking flux using the ladle slag of the present invention manufactured through the above steps.

Table 1 shows the primary compressive strengths of the added amounts of Comparative Examples 1 to 5 and Examples 1 to 4.

Table 3. Primary compressive strength for the amounts of Comparative Examples 1 to 5 and Examples 1 to 4 added

division Ladle slag bookbinder Compressive Strength (Day 1) 5 ~ 0.5mm 0.5 mm or less molasses Quicklime (CaO) Powder Lime powder water Comparative Example 1 75 25 - - 30 10 27.1 Comparative Example 2 100 0 15 One 25.4 Example 1 75 25 15 One 79.4 Example 2 50 50 15 One 69.3 Example 3 0 100 10 One 65.7 Example 4 50 50 15 3 65.5 Comparative Example 3 50 50 15 5 10.6 Comparative Example 4 50 50 15 0 26.2 Comparative Example 5 50 50 7 One 4.7

In Comparative Example 1 of Table 3, 30% by weight of lime powder and 10% by weight of lime powder and water were used as the binder based on 100 parts by weight of the ladle slag in which 75 parts by weight of the ladle slag 0.5 to 5 mm and 25 parts by weight of 0.5 mm or less were combined. The briquette was prepared by mixing, and the primary compressive strength of the briquette prepared by the above mixing ratio was 27.1 kgf / cm 2, and the compressive strength was weak, and the surface cracks and the amount of fine powder generation were excessively undesirable.

In Comparative Example 2, briquettes were prepared by mixing 15% by weight of molasses and 1% by weight of quicklime (CaO) powder as binders based on 100 parts by weight of ladle slag having a size of 0.5 to 5 mm of ladle slag. The primary compressive strength of briquettes was not as high as 25.4 kgf / ㎠ and the surface cracks of briquettes were not desirable.

In Comparative Example 3, 15% by weight of molasses and 5% by weight of quicklime (CaO) powder were mixed as binders based on 100 parts by weight of the ladle slag, which is 50 parts by weight of the ladle slag 0.5 to 5 mm and 50 parts by weight of 0.5 mm or less. The briquette was prepared by the above method, and the primary compressive strength of the briquette prepared by the above compounding ratio was not high as 10.6 kgf / cm 2. This is because the amount of quicklime (CaO) powder added as a binder is excessive and the unreacted quicklime (CaO) is present after the reaction with molasses, and the unreacted quicklime (CaO) powder is a factor that reduces the strength of briquettes. to be.

In Comparative Example 4, briquettes were prepared by using molasses as a binder in an amount of 15% by weight based on 100 parts by weight of the ladle slag in which 50 parts by weight of the ladle slag 0.5 to 5 mm and 50 parts by weight of 0.5 mm or less were combined. In this case, the lack of quick-acting lime (CaO) as a catalyst for accelerating the cure rate of molasses is not considered to be the strength of the briquettes.

In Comparative Example 5, a mixture of 7% by weight of molasses and 1% by weight of quicklime (CaO) powder was used as a binder based on 100 parts by weight of the ladle slag, which is 50 parts by weight of 0.5 to 5 mm and 50 parts by weight of 0.5 mm or less. It was judged that briquettes were produced in this case, and in this case, the amount of molasses used was insufficient and the intensity of briquettes could not be expressed.

In the case of Example 1, a mixture of 15% by weight of molasses and 1% by weight of quicklime (CaO) powder as a binder was added to 100 parts by weight of the ladle slag including 75 parts by weight of 0.5 to 5 mm and 25 parts by weight of 0.5 mm or less. The primary compressive strength of the briquette was 79.4 kgf / cm 2, and the synergistic effect of the compressive strength was superior to that of the briquette prepared by the conventional binder of Comparative Example 1. This is the result of increasing the rate of hardening of briquettes by the reaction of ladle slag of less than 0.5 mm and molasses and quicklime (CaO), thus showing the effect of increasing the initial strength, the increase in the initial strength is positively correlated with the productivity improvement. There is.

Examples 2 and 4 are 15% by weight of molasses and 1% by weight of quicklime (CaO) powder as a binder based on 100 parts by weight of ladle slag, which is 75 parts by weight of 0.5 to 5 mm and 25 parts by weight of 0.5 mm or less. Briquettes were prepared by mixing by weight%, and in this case, the compressive strength of briquettes was increased by the same reaction as in Example 1.

Example 3 produced briquettes with respect to 10% by weight molasses and 1% by weight of CaO powder as a binder with respect to 100 parts by weight of ladle slag, which combined 50 parts by weight of 0.5 to 5 mm in size and 50 parts by weight of 0.5 mm or less. Also in the case, the same compressive strength improvement effect as in Example 1 was obtained.

Therefore, in the manufacture of steelmaking flux by recycling the ladle slag of 5mm or less through the comparative examples and examples above, the molasses in the molasses addition step 40, the molasses 10 to 100 parts by weight of the ladle slag 5mm or less It is most effective to add 15 parts by weight to 15 parts by weight, and the amount of quicklime (CaO) powder added in the quicklime (CaO) powder addition step (50) is 0.5 parts by weight of quicklime (CaO) powder based on 100 parts by weight of ladle slag of 5 mm or less. It is most effective to add 3 parts by weight, and it is most effective to contain 25 parts by weight or more of ladle slag of 0.5 mm or less in 100 parts by weight of the ladle slag of 5 mm or less, which is the basis of the amount of each addition.

In addition, the steelmaking flux manufacturing method using the ladle slag of the present invention and the steelmaking flux manufactured using the same can be variously modified, so long as it does not deviate from the object scope of the present invention, all modified embodiments of the present invention It should be interpreted as being included in the scope of rights of the company.

According to the present invention, by using the steelmaking by-products while preventing the expansion and collapse of briquette molding due to the use of conventional limestone powder alone, the production cost in steelmaking operations can be lowered.

Claims (5)

In the method of manufacturing the steelmaking flux by recycling the ladle slag of less than 5mm generated during the refining process of the steelmaking process, A cooling step 10 of cooling the ladle slag, Crushing step 20 for crushing the cooled ladle slag, A sorting step 30 of sorting the ladle slag having a particle size of 5 mm or less among the crushed ladle slags, Molasses addition step (40) of adding molasses to the selected ladle slag, A quick lime (CaO) powder addition step (50) of adding quicklime (CaO) powder to the ladle slag to which molasses is added, A briquette forming step 60 of preparing briquettes using a ladle slag to which molasses and quicklime (CaO) powder are added, Steelmaking plus manufacturing method using a ladle slag characterized in that it comprises a curing step (70) for curing the briquettes. The method of claim 1, Molasses addition step 40, 10 to 15 parts by weight of molasses is added to 100 parts by weight of the ladle slag of 5 mm or less ladle slag flux manufacturing method using a ladle slag. The method of claim 1, Quick lime (CaO) powder addition step (50), A method for manufacturing steel flux using a ladle slag, wherein 0.5 part by weight to 3 parts by weight of quicklime (CaO) powder is added to 100 parts by weight of a ladle slag of 5 mm or less. The method of claim 2 or 3, 100 parts by weight of ladle slag less than 5mm, A steelmaking flux manufacturing method using a ladle slag, characterized in that it contains 25 parts by weight or more of the ladle slag of 0.5mm or less. Steelmaking flux produced by the method of claim 1

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