KR100843841B1 - Briquette having superior strength and formability - Google Patents

Abstract

The present invention relates to briquettes used as a substitute for scrap iron in converters, and more particularly, to briquettes in which powdered iron particles are used as a main raw material and steelmaking dust or fine coke is added thereto to improve strength and formability.

The present invention for achieving the above object is one or two selected from the group consisting of steelmaking dust: 5 to 15 parts by weight and fine powder coke: 3 to 6 parts by weight based on 100 parts by weight of iron, binder: 1 to 8 weight The technical subject matter of the briquette which is excellent in the intensity | strength and moldability which are formed negatively is excellent.

The briquettes of the present invention have an effect of remarkably improving the compressibility from 256 to 276 kgf and from 85.2 to 89.1% of formability.

Briquettes, iron, steelmaking dust, coke, strength, formability

Description

Briquette having superior strength and formability

The present invention relates to briquettes used as a substitute for scrap iron in converters, and more particularly, to briquettes in which powdered iron particles are used as a main raw material and steelmaking dust or fine coke is added thereto to improve strength and formability.

Iron is recovered from the slag generated in the steelmaking process or the steelmaking process by various separation methods, and the iron powder is agglomerated and manufactured as a scrap iron for steel scrap in the steelmaking process. Agglomeration techniques based on powders include pellets, briquetting, and sintering. The choice of agglomeration method is greatly influenced by the particle size of the raw material. In general, the pellet method is used when the particle size of the raw material is extremely fine, the briquetting method is used for particles of medium size having a maximum particle size of about 4 to 5 mm or less, and the sintering method is used for granulation having a maximum particle size of about 10 mm.

Usually, the iron-containing powdered iron particles extracted from the slag have a wide particle size distribution and exhibit a characteristic particle size of up to about 8-10 mm. The bulking method suitable for the particle size characteristic of this iron-iron particle | grain is the briquetting method, and is actually applied industrially. Binders and binding aids used in the manufacture of briquettes from powdered iron particles include molasses and slaked lime, water glass or water glass and slaked lime, and cements. However, the powdered iron particles have a large maximum particle size and a large particle size distribution, and thus, when molded into the briquettes in the pocket of the briquette, they are not easily formed into briquettes due to segregation of coarse particles, or they are often differentiated while being discharged from the pockets. Therefore, slaked lime is generally used as a bonding aid, because the filling of pores between raw material particles increases the filling density of briquettes, thereby improving moldability, and promoting the curing reaction of molasses or water glass to increase the strength. Because. In addition, when the binder is used as cements, an additional additive may not be required.

However, such slaked lime and cements are limited in their amount of use because they lower the quality of the bulk of the bulk material made of iron as an inorganic material.

Accordingly, an object of the present invention is to provide a briquette having excellent moldability and strength while selecting a binding aid that does not lower the grade of briquettes.

Briquettes of the present invention for achieving the above object is one or two selected from the group consisting of steelmaking dust: 5 to 15 parts by weight and fine powder coke: 3 to 6 parts by weight with respect to 100 parts by weight of iron, binder: 1 ~ It is composed of 8 parts by weight.

Hereinafter, the present invention will be described in detail.

In the present invention, the iron is a high iron content and can be used for high iron rods, and a representative example thereof is shown in Table 1 as iron powder extracted from slag of steelmaking and steelmaking processes used in conventional molasses. In addition, examples of the binder include molasses and water glass mainly used in conventional briquettes.

A feature of the present invention is the use of steelmaking dust and fine coke as a bonding aid. Steelmaking dust and fine coke are advantageous because they have a low gangue content with the advantage of being cheap as waste.

Steelmaking dust in the present invention helps maintain the iron concentration of briquettes made of iron because the iron content is high. In addition, since most of the coke is a combustible material, there is an effect of preventing the increase in the gangue content according to the use of the coke and an additional supply of calories. In other words, steelmaking dust plays a major role in improving compressive strength, and coke plays a major role in improving formability. Therefore, one or both of these can be used as binding agents for briquetting.

Steelmaking dust is mixed 5 to 15 parts by weight with respect to 100 parts by weight of iron, but the content should be at least 5 parts by weight to ensure a certain target strength, if more than 15 parts by weight will increase the strength but formability This gets worse.

In the case of coke, 3 to 6 parts by weight of iron is mixed with respect to 100 parts by weight of iron, the content of which is 3 parts by weight or more to ensure the target formability and strength, and more than 6 parts by weight becomes poor strength.

When steelmaking dust and coke are mixed together, the mixing amount thereof should be within 15 parts by weight. In the case of more than 15 parts by weight, the improvement of formability and strength is not significant.

As the binder, molasses and water glass are used, and a mixed amount thereof is used in an amount of 1 to 8 parts by weight based on 100 parts by weight of iron.

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

EXAMPLE

The particle size distribution and major chemical composition of iron, steelmaking dust and coke raw materials used in the present invention are shown. In addition, the chemical composition and particle size distribution of slaked lime used as a conventional binding aid is also shown in Table 1.

Particle size distribution Chemical composition + 5 mm + 1 mm 1 mm T, Fe,% M.Fe,% CaO,% C,% Iron 10-30 42-70 20-40 86.7 78.1 6.2 Slaked lime - 34.8 65.2 - - 65.1 - Steelmaking dust - - 100 65.2 43.4 18.5 0.8 Fine coke - - 100 - - - 87.6

As the main raw material of Table 1, molasses or water glass was used as a binder, and slag lime, steelmaking dust, and fine coke were added as a binder to prepare briquettes. Table 2 shows the formability and the compressive strength of the briquettes.

Briquettes were sized 30 mm x 40 mm and molding pressure was 2.5 ton. The determination of formability is carried out by analyzing the particle size of 20 kg of briquettes falling on the belt conveyor 60 cm below the briquettes and measuring the weight ratio of briquettes maintained at a particle diameter of 5 mm or more. It was judged that the original shape was well maintained from the impact, that is, the moldability was good.

A B C D E F G H I J K Binder molasses,% 3 3 3 3 3 3 3 3 3 3 3 Slaked lime,% 0 3 0 0 0 0 0 0 0 0 0 Steelmaking Dust,% 0 0 2 5 10 15 20 0 0 0 0 cokes 0 0 0 0 0 0 0 One 3 6 9 system 3 6 5 8 13 18 23 4 6 9 12 quality Formability,% 81.8 85.2 85.5 86.7 86.8 86.7 86.5 84.3 86.0 89.1 89.7 Strength, Kgf 215 256 258 268 271 276 278 247 257.2 256.5 251 Remarks Comparative example Comparative example Comparative example Inventive Example Inventive Example Inventive Example Comparative example Comparative example Inventive Example Inventive Example Comparative example

As shown in Table 2, the formability and compressive strength of briquettes using molasses and slaked lime are 85.2% and 256 kgf, respectively.

In contrast, when steelmaking dust was used in place of the slaked lime according to the present invention, the formability and the compressive strength were improved to a maximum of 86.8% and 276kgf. When the fine coke was used, the moldability and the compressibility reached a maximum of 89.1% and 257kgf. Could know. When the amount of steelmaking dust exceeded 15%, the moldability was slightly lowered and the strength was gradually improved. When the amount of coke exceeded 6% and reached 9%, the moldability was continuously improved, but the strength was lowered.

As described above, according to the present invention, when the slaked lime is replaced with steelmaking dust in the briquette manufacturing process using molasses or water glass, the compressive strength is remarkably improved to 256 → 276kgf, and moldability is slightly improved, and when slaked lime is replaced with coke, The formability was remarkably improved from 85.2 to 89.1%, but there was no significant change in strength. Therefore, it can be seen that the steelmaking dust proposed in the present invention has an effect of improving strength and the fine powder coke has an excellent effect of improving formability. In addition, when steelmaking dust is used in place of slaked lime, the iron content of steelmaking dust is high, which helps to maintain the iron concentration of briquettes made of iron, and when coke is used, coke is mostly combustible material. There is an effect of preventing the increase in the gangue content by using the and the additional supply of calories.

Claims (3)

One or two kinds selected from the group consisting of steelmaking dust: 5 to 15 parts by weight and fine powder coke: 3 to 6 parts by weight, and binder: 1 to 8 parts by weight of iron powder with excellent strength and formability . The briquette having excellent strength and formability according to claim 1, wherein the sum of the steelmaking dust and the fine powder coke is within 15 parts by weight. The briquette of claim 1, wherein the binder is one selected from the group consisting of molasses and wheat glass.