KR20020089080A - Silicon-carbon based briquette for rising temperature of melt - Google Patents

Abstract

PURPOSE: A silicon-carbon based briquette with high strength is provided to elevate the temperature of melt without dust scattering. CONSTITUTION: The silicon-carbon based briquette used in steelmaking industry comprises carbon 5 to 40 wt.% and 60 to 95 wt.% of ferrosilicon with a diameter of 1 to 10 mm. The silicon-carbon based briquette comprises carbon 5 to 30 wt.% and 70 to 95 wt.% of silicon carbide with a diameter of 1 to 10 mm.

Description

Silicon-carbon Based Briquette for Rising Temperature of Melt}

The present invention relates to a heat generating agent used for heating up a molten metal in a steelmaking process, and more particularly, to a silicon-carbon type heat generating agent having a briquette type having excellent temperature raising efficiency in a molten metal.

As a heating element for heating the steelmaking industry, ferro-silicon (Fe-Si) ingots having an Si content of about 75% by weight, anthracite coal or coke are mainly used. Ferrosilicon has a melting point of 1,350 ℃, which is lower than that of the molten metal, but is relatively high and its specific gravity is lower than that of the molten metal. Therefore, when the ferrosilicon ingot is introduced into the molten metal, the dissolution rate is slow and the oxidation reaction rate is delayed, thereby making it difficult to obtain a temperature raising effect of the molten metal within a short time. In addition, when the anthracite coal road melting point is added into the molten state in the ingot state, the oxidation reaction rate is slow, and the specific gravity is very low, so that it floats on the molten metal, and a large part of the oxidative calorific value does not contribute to the temperature rise of the molten metal.

In order to improve this problem, to increase the dissolution rate of ferrosilicon and carbon injected into the molten metal for the purpose of raising the temperature, the size of the ferrosisilium and anthracite coal is less than 10mm or smaller than the bulk, or silicon carbide (SiC) A method of increasing the dissolution rate by adding a was also adopted. However, these methods reduce the amount of particles used in the raw materials, which increases the amount of dust generated during the manufacturing and conveying process, resulting in environmental pollution due to dust scattering during transport and operation into the molten metal, as well as entanglement in the storage container. There is a problem that workability is degraded. In addition, the fine powder is collected in the unreacted state when put into the furnace, there is a problem that the error rate in the molten metal compared to the input amount is lowered.

The present invention is proposed to ameliorate the problem with these conventional heating agents.

An object of the present invention is to provide a briquette-type silicon-carbon-based heat generating agent which is excellent in the strength of the heat generating agent, the generation of fine powder is small and the dissolution rate is improved when the melting rate is added to the molten metal.

The present invention for achieving the above object in the heat generating agent is added in the molten metal for the temperature increase of the molten metal in the steelmaking process,

It is related with the silicon-carbon type heat generating agent for molten metal temperature rising of briquette form which contains carbon: 5-40 weight% and ferrosilicon of 1-10 mm in size: 60-95 weight%.

In addition, the present invention is a heat generating agent which is added in the molten metal to increase the temperature of the molten metal in the steelmaking process,

It relates to a silicon-carbon-based heat generating agent for molten metal temperature rising in briquette form, comprising carbon: 5 to 30% by weight and silicon carbide having a size of 1 to 10 mm: 70 to 95% by weight.

Hereinafter, the present invention will be described in detail.

The heat generating agent of the present invention is prepared in the form of briquette by blending carbon powder with ferrosilicon or silicon carbide. In the present invention, it is preferable to use a ferrosilicon or silicon carbide raw material having a particle size of 1 ~ 10mm. If the particle size of the raw material is more than 10mm, it is difficult to form into a briquette form and is easily broken due to low strength after molding, and the dissolution rate in the molten metal is sharply lowered, so that the rapid heating reaction cannot be achieved. On the other hand, the raw material particle size is less than 1mm is not preferable in consideration of cost or environmental aspects, such as not only increase the generation of dust during the production, but also requires a separate crushing process.

In addition, if the raw material added to the carbon powder is too large, briquette molding is difficult due to the high content of carbon having a low binding force, and the specific gravity of the briquette after molding is lower than that of the slag, so that it floats on the slag, thereby lowering the temperature raising efficiency for the molten metal. Not. Therefore, as a component of the silicon, when using ferrosilicon, carbon is about 5 to 40% by weight is appropriate, when using silicon carbide is suitable for blending about 5 to 30% by weight of carbon.

When the carbon powder is blended with the ferrosilicon or silicon carbide to prepare a briquette, the binder is added by a conventional method. As a caking additive, it may be an organic or inorganic caking additive, but an inorganic caking agent may be mixed with an inorganic substance in steel made of crude steel, which may affect trace components in the steel. In this case, the crude steel condition should be set by accurate calculation in advance. Therefore, in consideration of this point, it is more preferable to use an organic type binder which can be volatilized to air by oxidation in a furnace in crude steel.

Hereinafter, the present invention will be described in detail through examples.

Example 1

Inventive Example (1-6)

In order to determine the proper particle size of the heat generating agent according to the present invention, after mixing the carbon powder having a size of about 1 mm and a little starch while varying the particle diameter of the ferrosisilon and silicon carbide, the bracket was prepared and the compressive strength And dissolution rate was measured. The compressive strength was measured for the brackets manufactured in 100g units, and the dissolution rate was charged into 500g each of the induction furnaces in which 100Kg of deoxidized molten metal maintained at 1550 ° C was dissolved. The results are shown in Table 1.

division Particle diameter of ferrosilicon (mm) Silicon carbide particle size (mm) Compounding ratio (% by weight) Compressive strength (Kg / ㎠) Si yield after 5 minutes (weight%) Ferrosilicon Silicon carbide Carbon Inventive Example 1 One - 80 - 20 82 97 Inventive Example 2 5 - 80 - 20 76 97 Inventive Example 3 10 - 80 - 20 53 94 Inventive Example 4 - One - 80 20 86 98 Inventive Example 5 - 5 - 80 20 78 96 Inventive Example 6 - 10 - 80 20 52 93

Comparative Example (1-4)

Except that the particle size of the ferrosilicon and silicon carbide was changed as shown in Table 2, the compressive strength and the dissolution rate were measured in the same manner as the invention example, and the results are shown in Table 2.

division Particle diameter of ferrosilicon (mm) Silicon carbide particle size (mm) Compounding ratio (% by weight) Compressive strength (Kg / ㎠) Si yield after 5 minutes (weight%) Ferrosilicon Silicon carbide Carbon Comparative Example 1 12 - 80 - 20 36 87 Comparative Example 2 15 - 80 - 20 20 85 Comparative Example 3 - 12 - 80 20 34 88 Comparative Example 4 - 15 - 80 20 19 85

As shown in Table 2, in the case of the heat generating agent of Comparative Example (1-4) in which the particle size of the raw material exceeded 10 mm, the compressive strength of the heat generating agent was lower than the compressive strength (50 Kg / cm 2) used as a general steelmaking raw material. It was easy to break when the particle size was large, so that the dissolution rate was slowed, resulting in the Si error rate not reaching 90% by weight after 5 minutes in the molten metal.

On the contrary, as shown in Table 1, in the case of the heat generating agent of Inventive Example (1-6) manufactured using a raw material having a particle size of 10 mm or less, the silicone error rate after at least 5 kg / cm 2 of compressive strength and 5 minutes in the molten metal was increased. At least 90% by weight.

On the other hand, the heat generating agent using the raw material having a particle size of about 1mm or less is not only necessary for the crushing process to make a fine size, but also in terms of environmental aspects such as cost generation, such as dust generation.

Example 2

Inventive Example (7-15)

In order to find out the proper mixing ratio of raw materials, a heat generating agent was prepared at the mixing ratio as shown in Table 3 using ferrosilicon and silicon carbide having a particle size of about 3 mm, and the compressive strength, specific gravity, and temperature rise of the molten metal were measured for each heating agent. It was. Table 3 shows the results. Here, the compressive strength was measured as in Example 1. In addition, the temperature raising efficiency is about 100g of deoxidized molten metal at 1550 ° C., each about 500g of each heating agent is added, and after 5 minutes, the temperature of the molten metal is measured by the heat of oxidation of Si and carbon. Is expressed as a percentage.

division Particle diameter of ferrosilicon (mm) Silicon carbide particle size (mm) Compounding ratio (% by weight) Compressive strength (Kg / ㎠) importance Temperature increase efficiency (%) after 5 minutes Ferrosilicon Silicon carbide Carbon Inventive Example 7 3 - 95 - 5 98 3.4 63 Inventive Example 8 3 - 90 - 10 90 3.3 62 Inventive Example 9 3 - 80 - 20 82 3.2 60 Inventive Example 10 3 - 70 - 30 74 3.1 59 Inventive Example 11 3 - 60 - 40 58 2.9 58 Inventive Example 12 - 3 - 95 5 96 2.5 62 Inventive Example 13 - 3 - 90 10 91 2.45 60 Inventive Example 14 - 3 - 80 20 86 2.4 56 Inventive Example 15 - 3 - 70 30 73 2.3 56

Conventional example (1) (2)

Except for using ferrosilicon (30mm ingot) and silicon carbide (3mm) as a heat generating agent, the experiment was conducted in the same manner as in Example (7-15), and the results are shown in Table 4.

Comparative Example (5-7)

The experiment was carried out in the same manner as in Inventive Example (7-15), except that the mixing ratio of the raw material having a particle size of 1 mm was changed as shown in Table 4. Table 4 shows the result.

division Particle diameter of ferrosilicon (mm) Silicon carbide particle size (mm) Compounding ratio (% by weight) Compressive strength (Kg / ㎠) importance Temperature increase efficiency (weight%) after five minutes Ferrosilicon Silicon carbide Carbon Conventional Example 1 30 - 100 - - - 3.7 48 Conventional Example 2 3 3 - 100 - - 2.5 43 Comparative Example 5 One - 50 - 50 28 2.6 56 Comparative Example 6 - One - 60 40 46 2.25 54 Comparative Example 7 - One - 50 50 26 2.2 52

As shown in Table 4, in the case of Comparative Example (5-7) in which ferrosilicon or silicon carbide is out of the condition range, the compressive strength of the heat generating agent is lower than the strength normally used as steelmaking raw material, so it is easy to be damaged during handling. It was inappropriate.

In addition, in the case of using ferrosilicon alone, the conventional example (1) having a large particle size was not easily dissolved, and thus the temperature raising efficiency was low after the injection.In the case of the conventional example (2) using silicon carbide alone, even if the particle size was appropriate, It was found that the heating efficiency was low due to the large amount of heat generated in the air.

On the contrary, as shown in Table 3, in the case of the invention (7-15) that satisfies the appropriate condition range, it was found that the Bracket heating agent had a high compressive strength and an excellent temperature raising efficiency.

As described above, the bracket-type heat generating agent according to the present invention has a high intensity compared to the conventional heat generating agent, has little dust and excellent workability, and has a high dissolution rate when it is added into the molten metal.

Claims (2)

In the heat generating agent added in the molten metal to increase the temperature of the molten metal in the steelmaking process, Carbon: 5 to 40% by weight of ferrosilicon having a size of 1 to 10mm: 60 to 95% by weight, and a briquette-shaped molten silicon-carbon heating element. In the heat generating agent added in the molten metal to increase the temperature of the molten metal in the steelmaking process, Carbon: Silicon carbide having a temperature of 5 to 30% by weight and silicon carbide having a size of 1 to 10 mm: 70 to 95% by weight, and briquette form.