JPH10265782A - Production of coke for producing sintered ore and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a coke having the optimal grain size distribution suitable for the production of a sintered ore for blast furnaces in a small fine powder generation ratio by crushing coke with roll crushers in plural stages having small crushing ratios, subsequently. SOLUTION: Rolls 1 having a distance C1 between the rolls 1 and rolls 2 having a distance C2 (C2 <C1 ) between the rolls 2 are vertically disposed. Raw material coke 5 in an ore-storing hopper 3 is ground between rolls 1, and the ground coke having smaller sizes than the distance C1 between the rolls 1 is again ground between rolls 2. In the method, the grinding ratio of each step is small in comparison with that of a single roll crusher, and the coke can be crushed into the same grain size in multi-stages. The generation of fine powder due to the excessive grinding of the coke can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for producing coke used for producing sintered ore, which is a main raw material of a blast furnace.

[0002]

BACKGROUND OF THE INVENTION sinter, CaO-containing auxiliary raw materials limestone, etc. fine iron ore, a mixture of SiO ₂ containing auxiliary materials and coke such as silica stone and serpentinite, pseudo granulated by adding an appropriate water thereto After that, it is charged on the pallet of the downward suction type sintering machine, and after igniting the coke on the surface layer, the coke is sintered while sucking air downward, and the compounding material is sintered by the heat of combustion. The coke is obtained by crushing small and medium-sized coke under a sieve classified by a screen with a rod mill crusher.

[0003]

When the coke for sintering is a fine powder, the packing density increases and the permeability decreases, and the sintering speed decreases. The fine coke has a small heat holding power and is ignited. Because the fire extinguishes quickly, the temperature of the raw material layer on the pallet cannot be raised to a high temperature, the amount of melting decreases, and the strength decreases. Due to the remarkable decrease and the low heat retention of coke, heat propagation between coke particles is difficult to perform uniformly, and uneven coking and unburned portions are generated, resulting in problems such as reduced strength. on the other hand,
If the particle size is large, the heat holding power is large, so the amount of melting increases and the strength increases. ゝ The excessive generation of the melt impairs air permeability, lowers the firing rate, and the excessive generation of the melt This causes non-uniform ventilation in the raw material layer, resulting in non-uniform firing and unburned portions, causing problems such as reduction in strength.

The present inventors have conducted various experiments on the particle size of coke suitable for sinter production, and as a result, the coke particle size was 0.5%.
It has been found that the use of ~ 5 mm coke increases yield and improves productivity. However, it is not easy to obtain a coke having an appropriate particle size distribution of 0.5 to 5 mm with a conventional rod mill pulverizer, and coarse particles having a particle size of 5 mm or more increase or fine particles of 0.5 mm or less. The proportion tends to increase.

[0005] The inventors of the present invention conducted various experiments in consideration of crushing by a roll crusher. As a result, it has been found that not only a product having a size smaller than the set interval between the rolls is obtained, but also the generation ratio of fine powder is reduced. The present invention has been made as a result of further study on crushing by a roll crusher, and an object of the present invention is to provide a method and an apparatus capable of further reducing the generation rate of fine powder.

[0006]

The method of the present invention is characterized in that the crushing of coke by a roll crusher is performed in several stages with a reduced crushing ratio in each stage. The roll crusher used in the present invention may be composed of a plurality of roll crushers with different intervals between the rolls, but preferably one roll crusher provided with a plurality of sets of rolls with different intervals is used.

[0007] The apparatus of the present invention is an apparatus for performing the above-mentioned method, and comprises a roll crusher in which a plurality of sets of rolls having a narrower interval between rolls are installed vertically in a downward direction.

[0008]

Figure 1 DETAILED DESCRIPTION OF THE INVENTION, shows a conceptual diagram of a roll crusher according to the present invention, distance C ₁ between rolls
Roll 1 and a roll 2 with an interval C ₂ (C ₂ <C ₁ ) are arranged vertically, and a storage hopper 3 is placed on the roll 1,
A hopper 4 is provided between the rolls 1 and 2, and the raw coke 5 in the ore storage hopper 3 is first crushed between the upper rolls 1.
Most of the coke size smaller than the interval C ₁ between the time rolls is discharged without being crushed, to drop into the hopper 4. Then coke small hopper 4 size than C ₁ is crushed to a smaller size than the distance C ₂ between rolls between the lower roll 2. Similarly this time, most of the coke size smaller than the distance C ₂ between the rolls is discharged without being crushed.

Next, the crushing ratio by the roll crusher will be specifically described. The distance C ₁ between the roll 1 1
0 mm, by setting the distance C ₂ between rolls 2 to 3 mm, of the feed coke 5 below the diameter 30mm in貯鉱hopper 3, crushing ratio maximum diameter 30mm coke in the roll 1 30/10 = 3 / Coke having a maximum diameter of 10 mm on the roll 2 at a crushing ratio of 10/3 = 3.3 /
Crushed in 1.

[0010] On the other hand, when a single roll crusher using a set of rolls is used to set the distance between the rolls to 3 mm to obtain the same raw material coke having the same particle size, the coke having a maximum diameter of 3 mm is crushed. Crushed at 30/3 = 10/1, resulting in excessive pulverization.

[0011]

【Example】

Example 1 A raw coke having a particle size of 10 to 15 mm was crushed by using a roll crusher of the type shown in FIG. 1 and setting the interval C1 between the rolls ₁ to 5 mm and the interval C2 between the rolls ₂ to 3 mm.
The resulting product coke contained about 17% fine coke less than 0.5 mm. Incidentally, the same raw coke as above was crushed at one time by using a single-mounted roll crusher and setting the interval between the rolls to 3 mm. The resulting product coke contained about 21% fine coke of 0.5 mm or less.

[0012] Example 2 10 mm spacing C ₁ between the roll 1, the distance C ₂ between rolls 2
Was set to 5 mm, and the raw material coke having the same particle diameter of 10 to 15 mm as in Example 1 was crushed. The particle size distribution of the resulting product coke is indicated by white circles in FIG. Incidentally, the same coke was crushed once by using a single-mounted roll crusher with the roll interval set to 5 mm. The particle size distribution of the resulting product coke is indicated by black circles in the figure.

As shown in the above examples, the ratio of fine powder having a size of 0.5 mm or less decreased when the crushing ratio was reduced and crushed twice, rather than crushed once with a large crushing ratio.

[0014]

According to the first aspect of the present invention, by setting the interval between the rolls, it is possible to surely obtain particles having a particle size equal to or less than the set particle size, and crushing by a roll crusher is carried out in several stages, and Since the crushing ratio per time is reduced, excessive pulverization is eliminated, and the generation ratio of fine powder is reduced.

According to the second or third aspect of the present invention, it is possible to obtain a product coke with a low generation rate of fine powder by a single roll crusher.

[Brief description of the drawings]

FIG. 1 is a schematic view of a roll crusher according to the present invention.

FIG. 2 is a graph showing the particle size distribution of product coke obtained by using a single-type and a multiple-type roll crusher.

[Explanation of symbols]

 1, 2, roll 3, storage hopper 4, hopper 5, coke

Continued on the front page (72) Inventor Nobuyuki Tatsumoto 11-1 Showa-cho, Kure-shi, Hiroshima Nisshin Steel Co., Ltd. Kure Works

Claims (3)

[Claims] 1. A method for producing coke having an optimum particle size distribution used for producing sintered ore for a blast furnace, wherein the crushing of coke by a roll crusher is performed in several stages with a reduced crushing ratio in each stage. A method for producing coke for producing sintered ore, characterized by the following. 2. The method according to claim 1, wherein the roll crusher is a continuous roll crusher in which a plurality of sets of rolls are installed in a vertical direction. 3. An apparatus for carrying out the method according to claim 2, comprising a roll crusher in which a plurality of sets of rolls having a narrower interval between rolls are installed vertically in a downward direction.