JPH10259429A - Coke for producing sintered ore and producing device and method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily and surely obtain the most suitable grain size of coke used to production of sintered ore by crushing the grain size distribution of the coke to a specific range with a roll crusher. SOLUTION: The grain size distribution of the coke is made to 0.5-5.0 mm, desirably 1.0-5.0 mm. For this purpose, the roll crusher composed of paralleled one pair of rolls 11A, 11B rotation-driven with a motor, a fixed bearing 12 for supporting the roll 11A, a movable bearing 15 for supporting the roll 11B and advancing/retreating along a guide 13 and a hopper 16 arranged above the gap between the rolls, is used. The movable bearing 15 is advanced/retreated with a handle operation and the gap C between the rolls is adjusted to make the suitable gap and the coke from the hopper 16 is charged into the gap between the rolls and crushed. By this method, the crushing is executed to the one having mainly larger size than the gap C and the one having smaller than the gap C is not crushed or crushed at little chance, and the ratio of developing the fine powder is little.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[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] Fig. 1 shows an example of a flow of coke transport in a steel mill. A raw coke 1 is classified by a screen 2, and large coke is used as a raw material for a blast furnace and small and medium lump is used as a raw material. Is further classified by a screen 3, a part of the medium lump is crushed by a blast furnace 4, and the other medium lumps and small lumps are crushed by a rod mill crusher 5. Those having a certain size or less are used as sintering raw materials, while those having a certain size or more are crushed again by the rod mill crusher 5 together with small and medium-sized coke as return material.

[0004]

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 the production of sinter ore, and as a result, the particle size was 0.5
It has been found that the use of ~ 5 mm coke increases yield and improves productivity. To obtain coke having a particle size distribution of 0.5 to 5 mm, the operating conditions in a rod mill pulverizer may be adjusted, but this has the following problems.

That is, in order to minimize the proportion of fine powder having a particle size of 0.5 mm or less, increase the coke feed rate, reduce the number of rods used in a rod mill, or reduce the rod diameter. It is good to reduce the impact crushing force, but in this case, the return material to the crusher of 5 mm or more increases, and those of 5 mm or less decrease, the crushing effect decreases, and the operation rate of the equipment increases. In addition, the increase in the return material of 5 mm or more affects the entire coke conveyance flow in steelworks.

On the other hand, in order to minimize the proportion of coarse particles,
It is advisable to decrease the coke feed rate or increase the number of rods used in the crusher, or increase the rod diameter to increase the impact crushing force.However, as the proportion of fine powder of 0.5 mm or less increases. In addition, if the coke supply speed is reduced, the entire coke conveying flow in the steel mill is affected.

[0008] A first object of the present invention is to provide coke having an optimum particle size for use in sinter production.
A second object is to provide a manufacturing apparatus and a method that can easily and surely obtain coke of such a particle size.

[0009]

The invention for achieving the first object is characterized in that the particle size distribution of coke is set to 0.5 to 5.0 mm, preferably 1.0 to 5.0 mm. As shown in FIG. 2, the inventors of the present invention have found that coke A having a particle size of 0.5 mm or less and an average particle size of 0.21 mm, coke B having a particle size of 5 mm or less and an average particle size of 1.15 mm, Diameter 0.5-5.0m
m, coke C having an average particle size of 1.99 mm, particle size of 1.0
５5.0 mm, coke D having an average particle size of 2.53 mm and coke E having a particle size of 2.0 to 5.0 mm were added, and each of the quasi-granulated blended raw materials was uniformly charged into a heat-resistant container, and then mixed with the actual machine. A firing experiment was performed under the same conditions. FIG. 3 shows the sintering time min of each coke, FIG. 4 shows the yield indicating the percentage of products, and FIG. 5 shows the productivity t / h · m ² .

As shown in FIGS. 4 and 5, coke D having a particle size of 1.0 to 5.0 mm is best for both yield and productivity, and coke D having a particle size of 0.5 to 5.0 mm. C came after this. However, coke E having a large particle size having a particle size of 2.0 to 5.0 mm and an average particle size of 3.51 mm was reduced in both yield and productivity. The invention for achieving the second object is an invention for obtaining the above-mentioned coke, in which a roll having a pair of rolls juxtaposed at an appropriate interval and a charging port for charging coke between the rolls. Another invention is characterized in that the crusher is crushed by using the above-mentioned roll crusher and setting an interval between rolls to 3 mm.

The crushing by the roll crusher is mainly performed for the one having a size larger than the space between the rolls, and is not performed or rarely performed for the one having a size smaller than the space between the rolls. Compared with a rod mill crusher that crushes by the impact crushing force of a rod, the generation rate of fine powder is smaller, and only those having a size smaller than the interval between rolls can be obtained.

[0012]

FIG. 6 schematically shows a roll crusher used in the present invention.
A pair of rolls 11A and 11B driven to rotate by
A fixed bearing 12 for supporting the roll 11A;
A movable bearing 15 rotatably supported by the guide 13 and slidably supported by the guide 13 and advanced and retracted along the guide 13 by operating the handle 14; and a hopper 16 disposed above the space between the rolls and charging coke between the rolls. When the movable bearing 15 is moved forward and backward by operating the handle, the distance C between the rolls is adjusted.

FIG. 7 shows the use of the above-mentioned roll crusher.
It shows the particle size distribution of the coke obtained when the coke is pulverized by setting the interval C between the rolls to 2.0 mm, 3.1 mm, 4.2 mm, and 5.6 mm. From this figure, the coke G obtained when the interval C between the rolls is set to 3.1 mm has a ratio of fine powder of 0.5 mm or less, 30% or less,
It can be seen that there is no coarse particle exceeding 3.0 mm and an ideal particle size distribution can be obtained. By the way, the interval C between rolls is 2.0
The coke F obtained when it is set to mm is obtained in that the ratio of the fine powder of 0.5 mm or less is 40% or more, and when the interval C between the rolls is set to 4.2 mm and 5.6 mm. Coke H and I are not preferred in that coke exceeding 5 mm is obtained. The mark “〇” indicates the particle size distribution of coke J obtained by crushing with a conventional rod mill crusher. It is as follows,
The proportion of the fine powder of 0.5 mm or less was the same as that of coke F.

Next, coke J obtained by the rod mill crusher indicated by the symbol 〇 shown in FIG. 7 and coke G obtained when the distance C between rolls is set to 3.1 mm using a roll crusher are added. The quasi-granulated compounded raw materials were placed in containers with the same segregation charge as the actual machine, and simulated under the same conditions as the actual machine. Figure 8 shows the sintering time of each coke mi
n, FIG. 9 shows the yield indicating the ratio of products, and FIG. 10 shows the productivity t / h · m ² .

As shown in FIGS. 9 and 10, coke G
In the case of using coke, both the yield and the productivity were improved as compared with the case of using coke J.

[0016]

According to the first aspect of the present invention, the yield and productivity of sinter can be increased. According to the second aspect, the yield and productivity of sinter can be further improved. Can be raised. According to the third aspect of the invention, it is possible to easily and reliably obtain coke having a certain size or less, which is smaller than the interval between the rolls, and it is possible to reduce the generation rate of fine powder.

According to the fourth aspect of the invention, the maximum particle size of the coke obtained by adjusting the interval between the rolls can be changed. According to the fifth aspect of the invention, coke having an optimal particle size distribution can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing a flow of coke conveyance.

FIG. 2 is a graph showing the particle size distribution of each coke used in the experiment.

FIG. 3 is a graph showing a sintering time when a firing experiment was performed using the coke shown in FIG. 2;

FIG. 4 is a graph showing the yield.

FIG. 5 is a graph showing the productivity.

FIG. 6 is a schematic view of a roll crusher.

FIG. 7 is a graph showing a particle size distribution when coke is crushed using the roll crusher and the rod mill crusher shown in FIG.

FIG. 8 is a graph showing a sintering time when a firing experiment using coke obtained using a rod mill crusher and a roll crusher was performed.

FIG. 9 is a graph showing the yield.

FIG. 10 is a graph showing the productivity.

[Explanation of symbols]

 1. Raw Coke 2, 3, 6 Screen 4. Blast Furnace 5. Rod Mill Crusher 11A, 11B Roll 12, 15 Bearing 13 Guide 14 Handle 16 Hopper

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Keijiro Kawasaki 11-1, Showa-cho, Kure-shi, Hiroshima Nisshin Steel Co., Ltd. Inside Kure Works (72) Inventor Nobuyuki Tsutamoto 11-1, Showa-cho, Kure-shi, Hiroshima Nisshin Steel Co., Ltd.Kure Works

Claims (5)

[Claims] 1. A coke used for producing a sintered ore for a blast furnace, wherein the coke has a particle size distribution of 0.5 to 5.0 mm. 2. The coke according to claim 1, wherein the particle size distribution is 1.0 to 5.0 mm. 3. A roll crusher having a pair of rolls juxtaposed at appropriate intervals and an inlet for charging coke between the rolls.
Or an apparatus for producing coke according to 2. 4. The distance between the rolls is adjustable.
The described device. 5. A method of pulverizing coke using the apparatus according to claim 3 or 4, wherein the distance between the rolls is set to 3 mm.