JP3531409B2 - Granular raw materials for high grade sinter production - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a granular raw material having a high total iron content, which is advantageous for producing a high-grade sintered ore, and in particular, it is fired without deteriorating the quality of the sintered ore. The present invention relates to a granular raw material (generally pseudo particles) capable of reducing the SiO ₂ content in the slag.

[0002]

Sintered ore used as a blast furnace raw material is generally produced by the following method. First, the iron ore unloaded from the ship is piled up in a powder ore yard for each brand. After that, a pile of various powdered ores, CaO-containing auxiliary materials such as limestone and quicklime, SiO ₂ -containing auxiliary materials such as silica stone, carbonaceous materials such as sintered dust and coke, etc. at a preset ratio by the bedding method. Mix to make blending powder. This blending powder and each raw material such as limestone, quick lime, silica stone and / or serpentine, powder coke and / or anthracite, and return ores and, in some cases, plain ore,
Put it in each blending tank,
Sub-materials are continuously cut out. For these raw materials and auxiliary materials,
Further, an appropriate amount of water is added, and the mixture is mixed and regulated in the primary mixer, and then granulated in the secondary mixer.

The raw material granulated in this way, that is, the granular raw material (generally pseudo particles) for producing the sintered ore is continuously placed on the pallet of the endless moving great type sintering machine at a height of 50.
It is supplied in layers of about 0 to 700 mm. Next, the carbonaceous material of the surface layer is ignited in an ignition furnace, and the carbonaceous material is burned while forcibly sucking air downward. The granular raw material is sintered and agglomerated by the combustion heat generated at this time.

After cooling the sintered cake thus produced,
After crushing and sizing, particles of 3 to 5 mm or more are charged into the blast furnace as product sinter. 3 ~ generated in the crushing and sizing process
The powder sinter having a diameter of 5 mm or less is used again as a part of the sintering raw material as the return ore.

Sintered ore is used as a main raw material for the production of hot metal in a blast furnace, and in order to improve the production rate of hot metal, the content of total iron content in the sinter, that is, the supply of sinter with high iron grade is provided. Is requested. On the other hand, in order to improve the quality of the sinter, S that controls the amount of slag phase produced in the sinter
It becomes necessary to reduce the iO ₂ content. However, if the SiO ₂ content in the sinter is reduced, the amount of the slag phase having the binder function of the above-mentioned granular raw material (pseudo-particle) is reduced, and the strength of the sinter is reduced.

Therefore, as one of the methods for preventing the strength from decreasing even if the SiO ₂ content in the sinter is reduced, the reactivity of SiO ₂ added to the granular raw material at the time of firing is improved, As a conventional method, the unreacted amount of SiO ₂ is reduced and the amount of SiO ₂ that effectively acts on particle bonding is maintained. For example, in Japanese Examined Patent Publication No. 56-45458, silica particles, which are a source of SiO ₂ , are pulverized to have a particle size of less than 1 mm, and the total particle size of the sintered ore raw material is 1 m.
A method (prior art) in which the proportion of raw material particles of less than m is increased within the range of 25 to 60 wt.% is disclosed.

[0007]

However, in the above-mentioned prior art and other prior arts, the distribution state of the SiO ₂ -containing particles in the raw material of the sintered ore is such that the particles are dispersed inside the pseudo particles and fired. In the process, the strength of the sinter was maintained by forming a melt phase throughout the pseudo particles. An example of the distribution state of each constituent particle inside the pseudo particle prepared by this method is schematically shown in FIG.

In FIG. 4 (a), a coarse ore 6a having a relatively large particle size is used as a core, and fine SiO ₂ containing particles 19b, a CaO containing particle 20b and a fine coke 7b having a relatively small particle size are provided around the core. Pseudo-particle 21 formed by gathering
a is shown. On the other hand, in FIG. 4B, some fine ores 4b having a relatively small particle size are dispersed, and the fine SiO ₂ containing particles 19b, the fine CaO containing particles 20b and the fine coke 7b are filled in these gaps. Shows a pseudo particle 21b formed by being embedded. In addition, FIG. 4 (c) has one coarse grain coke 7a as a core, and fine SiO ₂ containing particles 19b, fine CaO containing particles 20b and fine ore 4b around the core.
Shows a pseudo particle 21c formed by agglomeration of particles.

The conventional method of dispersing SiO ₂ -containing particles in pseudo particles has the following disadvantages. Figure 4 (a)
As shown in the above, as a granular raw material for sintering, the coarse ore having a particle size of a size that does not cause the formation of pseudo particles and may exist alone, or the vicinity of a coarse ore having a particle size close to that, SiO _2- containing particles and CaO-containing particles are distributed. Therefore, FIG.
The SiO ₂ content is insufficient for pseudo particles containing a large number of fine ores as shown in (b), as compared with those for which a binder amount should be secured in order to secure the sintering strength. Thus
The strength of the sintered ore cannot be maintained sufficiently.

Further, coke added as a fuel source is also
As shown in (c) of FIG. 4, since the surroundings are covered with the fine-grain SiO ₂ -containing particles 2b, the fine-grain CaO-containing particles 3b and the fine-grain ore 1b, the coarse-grain coke 4 inside the pseudo-particle 5 is formed.
The flammability of a deteriorates, and some of it remains unburned. as a result,
Grains that have become insufficient in heat do not have sufficient strength for the sintered ore because the binding force of the particles is weak.

Due to the above problems, there is a limit to the reduction of the SiO ₂ content of the binder component in the pseudo particles, and the iron quality of the sintered ore cannot be improved. In order to solve the above problems, an object of the present invention is to provide SiO ₂
It was decided to obtain a granular raw material (pseudo-particles) for producing a sintered ore so that the strength of the sintered ore product does not decrease even if the content rate is reduced.

An object of the present invention is to solve the above problems, thereby reducing the SiO ₂ content of sinter, reducing the amount of slag generated during blast furnace operation, and contributing to the improvement of the hot metal production rate. It is to provide granular raw materials for the production of high-grade sinter.

[0013]

From the above-mentioned viewpoints, the inventors of the present invention have made extensive studies in developing a granular raw material for producing a high-grade sintered ore.

In order to solve the above-mentioned problems, the present inventors should classify each raw material for preparing pseudo particles according to the size of the particle size, and secure a true binder amount in order to secure the strength of the sinter. For the granulation of the ore on the fine grain side, the addition amount of the SiO ₂ -containing substance and the CaO-containing substance is intensively distributed, coarse ores with a certain grain size or more are not made into pseudo particles, and further, the above-mentioned SiO ₂ In order to distribute the coke distribution as a heat source according to the distribution tendency of the added amount of the contained substance and the CaO containing substance, and to improve the combustibility of the coke and prevent unburned particles, coarse particles having a certain particle size or more We focused on the fact that coke was not made into pseudo particles.

Based on the above observation, it was found that the problems can be solved by classifying each raw material according to an appropriate particle size and appropriately distributing the heat source substance. The present invention has been accomplished based on these findings, the granular raw material for high-grade sintered ore production in claim 1 wherein the ore, coke solid fuel, silicosis stone SiO ₂ containing material, as well as, limestone and CaO of Oishi ash
In the granular raw material for the production of sinter, which consists of contained substances,
The granular raw material is a mixture of pseudo particles, ore simple particles, and solid fuel simple particles, and the pseudo particles are fine ores having a particle diameter of less than 1 mm, fine solid fuel having a particle diameter of less than 1 mm, and SiO 2. _{It is} composed of _2- containing substance particles and CaO-containing substance particles, the ore simple substance particles are coarse-grained ores having a particle diameter of 1 mm or more, and the solid fuel simple substance particles are coarse-grain coke having a particle diameter of 1 mm or more. It has a special feature.

The particles having a particle size of 1 to 2 mm are intermediate particles which do not become a nucleus of the granulation and have a small action of adhering to other particles and granulating. Therefore, if particles having this particle size are mixed, the increase in the particle size of the granular raw material due to granulation is generally hindered, and the average particle size is reduced. On the other hand, in the granular raw material granulated with particles of 1 mm or less, since different kinds of particles having a large surface area are densely present, the generation of the melt is promoted during sintering, and the effect of improving the strength was obtained. From the above, in the present invention, the particle size of 1 mm is used as the classification point.

The granular raw material for producing a high-grade sinter according to claim 2 is the granular raw material according to claim 1, in which fine solid fuel particles having a particle size of less than 1 mm are distributed only on the surface portion as pseudo particles. It is characterized by being present.

The granular raw material for producing high-grade sinter according to claim 3 is the granular raw material according to claim 1 or 2, wherein the particle diameters of the SiO ₂ -containing substance particles and the CaO-containing substance particles in the pseudo particles are All of them are characterized by being less than 1 mm.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Next, an embodiment of the present invention will be described. FIG. 1 shows a flow chart for preparing a granular raw material for producing a sintered ore of the present invention.

1n and coke powder 2 of various brands are finely ore 4 and fine coke 5 having a particle size of less than 1 mm and coarse ore 6 of 1 mm or more in a sieving facility 3
And coarse grain coke 7. Fine ore 4, limestone 8 and quicklime 9 used as a binder, and silica stone 1
0 and water 11 are added, and the primary pseudo-particles 14 are prepared by mixing and adjusting the humidity with the primary mixer 12. However, the SiO ₂ content is contained in the powder ore 1 and the gangue content of the fine coke, and when preparing pseudo particles having a low SiO ₂ content,
In many cases, it is not necessary to add silica stone 10 as a SiO ₂ source. Next, the primary pseudo particles 14 and the fine coke 5 are charged into the coating mixer 15 and granulated again. Thus, the fine coke 5 on the surface of the primary pseudo particles 14
The pseudo particles 16 to which is attached are prepared. Fine coke 5
Thus, it is desirable that the entire amount is attached to the surface of the primary pseudo particles 14 (hereinafter referred to as “exterior”) because of its excellent strength and reducibility. However, in this case, there is a difference in granulation property depending on the brand of the ore, and if it is difficult to cover the entire amount of the fine coke 5 with the ore, a part of the coke 5 is mixed in advance before charging the primary mixer 12, and then mixed and adjusted with the primary mixer. Keep it moist (below,
"Interior"). From the beginning, the fine coke 5 may be entirely mixed and conditioned with the primary mixer 12.

On the other hand, a coarse-grained ore 6 and a coarse-grained coke 7 having a grain size of 1 mm or more, and the pseudo-particle 16 are mixed in a mixer 1
Charge in 7 and mix. In order to achieve the features of the present invention, the coarse ore 6, the coarse coke 7 and the pseudo particles are appropriately mixed, and the mixing action works even during transportation and charging of the sintering machine. It is not always necessary to install the mixing mixer 17. Thus, the granular raw material 18 for producing a sinter having the characteristics of the present invention is obtained.

FIG. 2 is a schematic sectional view for explaining the formation process of the granular raw material for sinter according to the present invention and the characteristics of the structure. In the same figure, (a) represents fine ore 4 and limestone 8 + quick lime 9 (+ silica stone 10), (b) represents primary pseudo particles 14 and fine coke 5 granulated from (a), And (c) represents the granular raw material according to claim 2 of the present invention, which is composed of a mixture of the pseudo particles 16 in which the fine coke 5 is attached to the surface of the primary pseudo particles 14, the coarse ore 6, and the coarse coke 7. It is a thing.

In the granular raw material for sinter according to the present invention,
Since the pseudo particles 16 secure a sufficient amount of binder ((limestone 8 + quick lime 9 (+ silica stone 10)) and have a sufficient amount of fine coke 5 adhered to the surface, the coke flammability is improved. Due to its superiority, the binder is supplied with a sufficient amount of heat necessary for melt formation, and particle bonding strongly progresses during the firing process. The particles of the ore exist as a sinter ore in which a thin fusion layer is formed on the surface with itself as a nucleus.Since coarse ores usually have high density, the diffusion rate of reducing gas into the interior is high. Since it is slow, the reduction of the core portion is delayed, but in the case of the present invention, since the surface fusion layer is thin, the rate of reduction to the particle core is high, and the reducibility is improved.

[0024]

EXAMPLES Next, the granular raw material for producing high-grade sinter according to the present invention will be further described by way of examples.

According to the flow chart for preparing the granular raw material of the present invention shown in FIG. 1, granular raw materials within the scope of the present invention (Examples 1 to 6) and granular raw materials outside the scope of the present invention (Comparative Examples 1 to 1)
3) was prepared and fired to produce sinter. Table 1 shows the preparation conditions for the granular raw materials of the examples and comparative examples.

[0026]

[Table 1]

In each of the examples, the iron ore and the solid fuel were classified by 1 mm, the total iron content target was a constant value of 60 wt.% And the basicity was a constant value of 2.0. In the case where the fine solid fuel is added to the primary pseudo particles as an external method or the interior is used as a method for adding the fine solid fuel, a SiO ₂ -containing substance and a CaO-containing substance as a binder are added to 1 mm.
A test was carried out by appropriately combining the cases where the classification was performed with and when the levels of the SiO ₂ content and the slag content were changed.

On the other hand, in the comparative example, the conventional ore and fine solid fuel are classified into SiO 2 without classification according to the size of the particle.
_{2 The} containing substance and the CaO containing substance were also mixed without classifying the particle size, and the fine solid fuel was incorporated in the primary pseudo particles (Comparative Example 1), the exterior (Comparative Example 2), and the ore and the fine particles. The solid fuel was classified with a particle diameter of 2 mm, the particle diameters of the SiO ₂ -containing substance and the CaO-containing substance were not classified, and the fine solid fuel was incorporated in the primary pseudo particles (Comparative Example 3). However, the target for the total iron content was a constant value of 60 wt.% And the basicity was a constant value of 2.0, which was the same as in the example. Table 2 shows the chemical composition of the iron ore used.

[0029]

[Table 2]

FIG. 3 shows typical operation result results (production rate and product yield) for each example and each comparative example.
In addition, the strength characteristics (TI ₊₁₀ ) and reducibility (J
The test results of IS-RI) and reduction dust resistance (RDI) are shown.

The following matters can be seen from FIG. Sintered ores obtained by firing the pseudo particles of the comparative example, which is outside the scope of the present invention, are both inferior in at least one of reducibility and reduction pulverization resistance, and both are excellent. There is nothing.

On the other hand, the sinter according to the present invention is excellent in all of the strength properties, the reducibility and the reduction pulverization resistance of the sinter. Moreover, the production rate and product yield are also excellent.

[0033]

As described above, according to the present invention,
Even if the SiO ₂ content in the granular raw material is reduced and the total iron content is increased, the sintered mineral product produced using this granular raw material does not cause a decrease in strength and an excellent product is obtained. Therefore, stable blast furnace operation can be performed, and moreover, hot metal can be produced with good yield. As described above, it is possible to provide a granular raw material for producing a high-grade sinter having an excellent product quality, which brings industrially useful effects.

[Brief description of drawings]

FIG. 1 is a flow chart for preparing a granular raw material for producing a sinter according to the present invention.

FIG. 2 is a schematic cross-sectional view illustrating the formation process of the granular raw material for sinter according to the present invention and the characteristics of the configuration.

FIG. 3 is a graph showing operation results of granular raw materials (pseudo particles) for sinter ores of Examples and Comparative Examples, and quality characteristics of the sinter.

FIG. 4 is a schematic diagram showing a distribution state of each constituent particle inside a conventional pseudo particle.

[Explanation of symbols]

1 powdered ore 1a, ..., n various brands of powdered ore 2 coke powder 3 sieving device 4 fine ore 5 fine coke 6 coarse ore 6a relatively large coarse ore 7 coarse coke 8 limestone 9 quicklime 10 silica 11 water 12 primary mixer 14 primary pseudo particles 15 coated mixer 16 pseudoparticles 17 a mixer 18 particulate material 19b relatively particle size of small particulate SiO ₂ containing particles 20b relatively particle diameter of small fine CaO-containing particles 21a pseudo particles (conventional Example) 21b Pseudoparticles (conventional example) 21c Pseudoparticles (conventional example)

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hideaki Sato, 1-2, Marunouchi, Chiyoda-ku, Tokyo Japan Steel Pipe Co., Ltd. (72) Takashi Watanabe, 1-2, Marunouchi, Chiyoda-ku, Tokyo Nippon Steel Pipe (72) Inventor Shoichi Rokugawa 1-2-2 Marunouchi, Chiyoda-ku, Tokyo Nippon Steel Tube Co., Ltd. (72) In-house Takanori Inoguchi 1-2-1 Marunouchi, Chiyoda-ku, Tokyo Nippon Steel Tube Co., Ltd. (56) Reference JP 54-71005 (JP, A) JP 60-138020 (JP, A) JP 60-169527 (JP, A) JP 8-291341 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C22B 1/00-61/00

Claims (3)

(57) [Claims] 1. A ore, coke of solid fuel, the silicofluoride stone Si
O ₂ containing material, and consists of CaO-containing material limestone and raw lime in particulate material for sintered ore production, the particulate material has a pseudo particles, and the ore alone grain, mixture comprising solid fuel alone particle And the pseudo particles have a particle size of 1 m.
a fine ore of less than m, a fine solid fuel having a particle size of less than 1 mm, a SiO ₂ -containing substance particle, and a CaO-containing substance particle, wherein the ore simple substance particle is a coarse-grained ore having a particle size of 1 mm or more, and The granular raw material for producing high-grade sinter, characterized in that the solid fuel simple particles are coarse coke having a particle diameter of 1 mm or more. 2. The granular raw material for producing a high-quality sintered ore according to claim 1, wherein the pseudo-particles are such that the fine solid fuel having a particle diameter of less than 1 mm is distributed only on the surface portion. . 3. The particle diameters of the SiO ₂ -containing substance particles and the CaO-containing substance grains in the pseudo particles are all 1 mm.
The granular raw material for producing high-grade sinter according to claim 1 or 2, characterized in that it is less than.