KR20040079744A - Premelted boron slag composition for production of mold flux and mold flux manufactured therefrom - Google Patents

Abstract

PURPOSE: A premelted boron slag composition for manufacturing mold flux is provided to minimize moisture in the mold flux and improve uniform melting characteristics, fluidity and viscosity by developing a premelted boron slag composition that does not have hydration reaction, and a mold flux manufactured from the same is provided. CONSTITUTION: The premelted boron slag composition for manufacturing mold flux comprises 20 to 50 wt.% of SiO2, 20 to 50 wt.% of CaO, 5 to 35 wt.% of B2O3, 1 to 15 wt.% of Na2O, and 1 to 10 wt.% of Al2O3, wherein the premelted boron slag composition is formed of particulate having particle size of 95% or more of which pass through 200 or 325 meshes. The mold flux is characterized in that it is manufactured from the premelted boron slag composition comprising 20 to 50 wt.% of SiO2, 20 to 50 wt.% of CaO, 5 to 35 wt.% of B2O3, 1 to 15 wt.% of Na2O, and 1 to 10 wt.% of Al2O3.

Description

Electrolytic boron slag composition for mold flux production and mold flux prepared therefrom {PREMELTED BORON SLAG COMPOSITION FOR PRODUCTION OF MOLD FLUX AND MOLD FLUX MANUFACTURED THEREFROM}

The present invention relates to a molten boron slag composition as a raw material for the adjustment of the boron component used in the manufacture of the mold flux, and a mold flux prepared therefrom. Boron slag composition as a molten raw material for adjusting boron components with lower melting point, more uniform chemical composition and more uniform melting characteristics and no hydration reaction, and melt properties, fluidity, viscosity, etc. It relates to a mold flux that can be adjusted in various ways.

In general, the mold flux is an important consumable subsidiary material used as an additive in a mold in the continuous casting process of steel, and when it is put on the molten steel in the mold, the molten steel receives three layers of an unmelted layer, a sintered layer, and a molten slag layer. The main function of the mold flux is to keep the molten steel in close contact with the carbon content, to prevent the solidification of the molten steel, to prevent the reoxidation of the molten steel by the atmosphere, and to absorb the inclusions floating from the surface of the molten steel. Function, the lubrication function between the coagulation cell and the mold, and the heat transfer medium between the coagulation cell and the mold. In particular, the mold flux changes into liquid slag in contact with molten steel and flows between the mold and the solidification cell to lubricate, thereby improving operation stability and continuous surface quality of the continuous casting process.

In general, the mold flux is a mixed material of various compounds composed of SiO ₂ , CaO, MgO, Al ₂ O ₃ , Na ₂ O, Fe ₂ O ₃ , MnO ₂ , B ₂ O ₃ , C, and the like.

When the raw material of the mold flux is a raw material that is not a natural raw material, the chemical and physical characteristics are better than those of the natural raw material. The molten mold flux raw material has uniform melting characteristics. This proves that they have a uniform chemical composition.

In addition, it is necessary to use the molten raw material as a raw material for adjusting the melting characteristics of the molten and natural acid-based raw material having a single melting characteristics to have the above good characteristics. Therefore, the raw material for maintaining the properties of the molten substrate raw material as well as adjusting the single melting characteristics of the substrate raw material should be a compound having a uniform chemical composition that is uniformly melted at a constant temperature. In other words, it must be a molten material that consists of several component systems.

Conventionally, a multi-component melting and natural acid based raw material is used, and a mixed type having a characteristic of melting at a proper temperature by mixing a high-purity flux material having a low melting point for adjusting melting characteristics (Mixed) ) Mold flux was mainly used.

However, such a mixed mold flux exhibits a nonuniform chemical composition in the fine region due to the mixing of raw materials, and moreover, has a nonuniform melting characteristic due to segregation of the chemical composition. Even though the melting raw material having a low melting point was melted, in the case of a natural acid based raw material having a high melting point, the melting raw material was not melted but floated in the molten slag pool.

The present invention has been made to solve the above-mentioned problems of the prior art, an object of the present invention is a uniformity in which the raw material for adjusting the boron component is not hydrated by reacting with water without the crystal moisture in the raw material to be injected to manufacture the mold flux. To provide a molten boron slag composition which is a melt synthesis raw material having a chemical composition distribution and having a low melting point.

In addition, another object of the present invention is to provide a mold flux prepared using the molten boron slag composition, which can improve the melting characteristics of the mold flux and exhibit uniform melting characteristics, thereby contributing to continuous casting operation stability and slab quality improvement. There is.

1 is a schematic system diagram for producing a molten boron slag composition according to the present invention,

Figure 2 is a flow chart showing a method for producing a mold flux using the molten boron slag composition according to the present invention.

<Explanation of symbols for the main parts of the drawings>

1: Raw material input bucket 2: Raw material input port

3: household cyclone 4: blower

5: melting furnace 6: cooling water

7: air hole 8: hot water outlet

9: ejector 10: cleaning dust collector

11: chimney

In order to achieve the above object of the present invention, the present invention provides a melted raw material (Premelted Materials) of CaO-SiO ₂ -B ₂ O ₃ -Na ₂ O-Al ₂ O ₃ (5-membered system, electrolytic boron slag composition) It was developed to adjust the uniform melting characteristics of a single raw material based on a natural acid to have a uniform melting characteristics. In addition, the molten boron slag composition according to the present invention minimizes the formation of crystal moisture in the mold flux manufacturing process, so that the molten steel leakage caused by the crystal water contained in the mold flux when picked up in the molten steel is picked up in the molten steel. Minimize the break out.

In particular, the molten boron slag composition for producing a mold flux according to the present invention is _{20 to} 50wt% SiO ₂ , _{20 to} 50wt% CaO, 5 to 35wt% B ₂ O ₃ , _{1 to} 15wt% Na ₂ O and 1 to ₂ Al ₃ O ₃ It is characterized by having a composition of 10wt%.

In addition, the mold flux according to the present invention is characterized in that the molten boron slag composition is prepared by using a molten raw material for adjusting the boron component of the base material obtained by melting and cooling in the air and then grinding it.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

1 is a schematic system diagram for producing the molten boron slag composition according to the present invention, Figure 2 is a flow chart showing a method for producing a mold flux using the molten boron slag composition according to the present invention.

The molten boron slag composition and a method for producing a mold flux using the same according to the present invention will be described with reference to FIGS. 1 and 2.

First, 20 wt% of CaCO ₃ (limestone), 15 wt% of SiO ₂ (silica), 65 wt% of Na ₂ B ₄ O ₇ 5H ₂ O (Borax Pentahydrate) and fuel using the raw material input bucket (1) Cokes as is introduced into the melting furnace 5 through the raw material inlet 2 at a ratio of 7: 3 (raw material: fuel). At this _{time, SiO 2 20~50wt%, CaO 20~50wt} %, B 2 O 3 5~35wt%, Na 2 O 1~15wt%, Al 2 O 3 ratio of the content of the melt, preferably 1~10wt% synthetic search Do.

The main component of the molten boron slag composition is SiO ₂ -CaO-B ₂ O ₃ , and Al ₂ O ₃ is an impurity. This compound became a region of low melting point and attempted to reach a lower melting point by adding Na ₂ O.

Subsequently, the raw material introduced by the heat of combustion of the coke becomes a liquid CaO—SiO ₂ —B ₂ O ₃ —Na ₂ O—Al ₂ O ₃ (a dedicated boron slag composition) and flows out continuously to the tap-hole 8. The molten boron slag composition in the form of powder is obtained by cooling the molten boron slag composition exiting the tapping hole 8 in the air in the air.

Subsequently, the cooled molten boron slag composition is pulverized into a powder form of fine particles passing 95% or more through 200 mesh or 325 mesh through a grinding process.

The mold flux is manufactured using this electrolytic boron slag composition as a raw material.

Reference numeral 3 denotes a collector cyclone, 4 denotes a blowhole, 5 denotes a melting furnace, 6 denotes a cooling water, 7 denotes an air hole, 8 denotes a hot water outlet, 9 denotes an exhauster, 10 denotes a scrubber, and 11 denotes a chimney.

<Example>

(1) Preparation of molten boron slag composition

First, 20 wt% of CaCO ₃ (limestone), 15 wt% of SiO ₂ (silica), 65 wt% of Na ₂ B ₄ O ₇ · 5H ₂ O (Borax Pentahydrate) together with the fuel (coke) After the addition, the molten crystals of borax hydrate are vaporized and melted and synthesized with the remaining raw materials to form a molten boron slag composition. As a result, it could be confirmed that SiO ₂ 32wt%, CaO 33wt%, B ₂ O ₃ 20wt%, Na ₂ O 9wt%, Al ₂ O ₃ 2wt% ratio.

Subsequently, the molten material was cooled outside the melting furnace 5 and then powdered through a pulverization process to prepare a molten boron slag composition.

In the molten boron slag composition, the crystallized water of borax pantahydrate containing crystallized water is evaporated in the melting furnace 5 and melted and synthesized with the injected raw material to form anhydrous molten boron slag composition. The molten boron slag becomes inactive in contact with water, and furthermore, minimizes the formation of crystal moisture in the mold flux manufacturing process, so that the crystal moisture contained in the mold flux is picked up into the molten steel during the continuous casting process. It can minimize the break out caused by the molten steel (Break Out).

(2) mold flux manufacturing

The molten boron slag composition was used as a raw material and added together with other raw materials to produce a mold flux, which was applied to a continuous casting process of slabs and blebs of Gwangyang Works, Slabs and Blums of Pohang Works, and I & I Steel Blum. It was found that the continuous casting operation stability and cast quality were improved.

According to the molten boron slag composition for producing a mold flux according to the present invention and a mold flux prepared therefrom, a molten reaction-free molten boron slag composition is developed, and the mold flux is prepared using the same to minimize crystal moisture in the mold flux. Improved or improved uniform melt properties and fluidity and viscosity can contribute to operational stability and surface quality due to smooth workability in continuous casting processes.

Claims (3)

A molten boron slag composition for producing a mold flux, comprising the following composition. end. 20-50 wt% SiO ₂ I. 20-50 wt% CaO All. 5-35 wt% B ₂ O ₃ la. 1-15 wt% Na ₂ O hemp. 1-10 wt% Al ₂ O ₃ The molten boron slag composition of claim 1, wherein the molten boron slag composition is composed of fine particles having a particle size of 95% or more passing through 200 or 325 meshes. The mold flux manufactured using the electrolytic boron slag composition of Claim 1 or 2 as a raw material.