JPH0442443B2 - - Google Patents

Description

[Detailed description of the invention]

(b) Industrial application field The present invention relates to a method of charging raw materials into a blast furnace, and more specifically, the present invention relates to a method of charging raw materials into a blast furnace. The present invention relates to a method of mixing lump coke. (b) Conventional technology A method of mixing small coke into ore and charging it has been practiced in the past, but in the conventional technology, small coke does not exist uniformly in the ore layer and segregation occurs, so the above-mentioned The effect could not be fully demonstrated. For example, even if small coke is cut out in small quantities in a storage tank and mixed uniformly with ore on a conveyor, when it passes through a surge hopper, the coke is not discharged uniformly when the hopper is discharged, so the charging belt
Small coke particles in the ore were unevenly distributed in the longitudinal direction of the conveyor. Furthermore, uneven distribution of coke in the ore layer also occurs when ore is charged into the blast furnace. As shown in Fig. 2, even after charging lump coke 2 into the blast furnace, ore 4 with complete mixture of small coke 3 is charged.
The ore and the small coke are re-separated while falling from the large bell or bell-less chute and descending the accumulated lump coke slope 21, and the small coke with low specific gravity is unevenly distributed near the surface of the ore layer. Therefore, as shown in Figure 3A and B, the ore is divided into at least two parts, the initial charge of ore 4' is mixed with small coke 3, and the final charge of ore 4'' is mixed with ore. A method (Japanese Patent Laid-Open No. 59-211509) has been proposed in which small coke 3 is charged without mixing. By doing this, when the initial charge of ore is charged into the furnace, mixing is not required. Even if the small coke 3 is unevenly distributed near the surface of the ore layer, the final charge of ore is charged on top of it, so the small coke can be reliably trapped in the ore layer. Even with this method, the segregation of the mixed ratio of small coke 3 in the height direction in the ore layer is large, and the small coke 3 in the ore 4 is
The effect of the mixture cannot be fully demonstrated. (c) Problems to be solved by the present invention The problems to be solved by the present invention are the uneven distribution of small coke in the ore before charging into the blast furnace and the problem in the blast furnace charging process. The aim is to eliminate the uneven distribution of small coke in the ore layer at the time of input. (d) Means for Solving the Problems The method of charging raw materials for a blast furnace of the present invention includes charging the coke in parts when charging the raw materials into the blast furnace, and adding small lumps to the final charged coke. using coke, charging the small coke near the position where the initially charged ore falls in the furnace, charging the ore in parts, charging only the ore at the initial stage of ore charging; During the second ore charging, the above problem can be solved by depositing small coke at the bottom of the large bell hopper or bellless bunker, then depositing ore at the top and charging into the furnace at the same time. points are resolved. (e) Examples The method of the present invention will be specifically explained with reference to the drawings. The method of the present invention can be diagrammatically written as follows in comparison with the conventional method. Invention method (Figure 1): C _L ↓C _S ↓O〓↓ (C _S +O〓)
↓ Conventional method (Fig. 2): C _L ↓ (OC _S ) ↓ Conventional method (Fig. 3): C _L ↓ (O〓C _S )↓O〓↓ Where, C _L : Lump coke O: Initial stage Charging ore ↓: Charge into the furnace C _S : Small coke O〓: Final charging ore (A+B): In a large bellhopper or bellless bunker, raw material A is deposited in the lower part and raw material B in the upper part, At the same time, install the furnace. (AB): A mixture of raw material B and raw material A is charged into a large bell hopper or bellless bunker, and loaded into the furnace. In the conventional method shown in FIG. 2, after charging lump coke 2, small lump coke 3 is mixed with the entire amount of ore 4 and charged into the furnace. In the conventional method shown in Figure 3, the initially charged ore 4' (O〓) contains small coke 3 ( _CS ).
(Fig. 3), the final charging ore is 4″ (O〓)
Do not mix small coke 3 with. On the other hand, in the method of the present invention, the initially charged coke is separately charged as shown in FIG. Lump coke 2 ( _CL )
After charging, small coke 3 (C _S ) is added to ore 4 (O〓)
Charge around the dropping position. Small coke 3 is
As described below, this is coke to be mixed in the initially charged ore 4. Next, the initial charging ore 4 without mixed small coke 3 is charged. When charging the ore, the small coke 3 near the falling position is scraped off by the impact energy of the falling ore 4, mixed with the ore 4, and swept toward the center of the furnace, creating a wide mixed layer in the center. form. Regarding the formation of a mixed layer during ore charging, Y.
“Transactions of Iron and
Steel Institute of Japan, Volume 23, 1983 (1045
There is a report in ``Page)''. The inventors also created a full-scale fan-shaped model (fan angle 20°).
We investigated the effect on the amount of mixed layer formation by varying the coke particle size near the ore falling position using It was confirmed. The feature of the present invention is that the small coke 3 (C _S ) mixed into the initial charging ore 4' (O〓) is replaced by the lump coke 2
(C _L ) and the charging position should be near the falling position of the initially charged ore 4' (O〓) to effectively utilize the falling impact energy during the above-mentioned ore charging. That's true. Next, we will discuss the method of mixing small coke 3 into charged ore 4'' (O〓) from the second time onward.Before charging ore 4'' into a large bell hopper or bellless bunker, Small coke 3 to be mixed into the ore layer is charged into a large bell hopper or bellless bunker and propelled downward. On top of that, 2
From the first time onwards, the charged ore 4" (O〓) is propelled. The accumulation of raw materials in the large bell hopper and bellless bunker is schematically shown in Figure 4 A and B. In this state, the bell type charging is carried out. In case A, when the large bell 5 is opened to charge raw materials into the furnace, the small coke 3 on the fixed wall 6 side is first discharged from the large bell hopper, and then the ore 4 deposited on the top is discharged. '' is discharged, and finally the small coke 3 on the large bell side is discharged. In the case of bellless charging B, when the gate valve 8 is opened, the small coke 3 on the fixed wall 6 side is first discharged from the large bell hopper, then the ore 4'' accumulated on the top is discharged, and finally The small coke 3 on the large bell side is discharged.In the case of bellless charging B, when the gate valve 8 is opened, the small coke 3 accumulated at the bottom of the bellless bunker 7 is first discharged, and then the small coke 3 is discharged at the top. The accumulated ore 4'' is discharged, and finally the small coke 3 on the bunker wall is discharged. Therefore, the final state of accumulation of small coke 3 in the ore layer is as shown in FIG. The second and subsequent mixing of the small coke 3 into the charged ore 4″ (O〓) is carried out using the raw material discharge characteristics from the large bell hopper or bellless bunker, and most of the small coke 3 is It is possible to suppress uneven distribution near the surface of the ore layer.In addition, when ore 4'' is deposited at the bottom of a large bell hopper or bellless bunker and small coke 3 is deposited at the top, the small coke 3 Although it is discharged during the middle stage of charging, it is likely to re-separate in the furnace and be unevenly distributed near the surface of the ore layer, making it impossible to fully achieve the intended purpose. The particle size range of the small coke 3 to be used is determined by the lower limit of the particle size of the small coke used in the blast furnace and the upper limit at which the small coke undergoes a solution loss reaction and disappears before reaching the upper part of the dripping zone. Further, the lower limit particle size is determined by the upper limit of coke powder used in the sintering machine and the upper limit that does not impede the permeability in the blast furnace. Usually particle sizes of 7 to 20 mm are used. Further, although the example in which the number of charged ore and coke is divided into two is shown, the same effect can be obtained even if the number of divided parts is increased. (f) Effects In order to confirm the effects of the present invention method, a charging test was carried out along with the conventional method using the above-mentioned full-scale fan-shaped model, and the mixed ratio distribution of small coke in the ore layer was measured. did. The test conditions at this time are shown in Table 1, and the particle size distribution of the coke used is shown in Table 2. After the charging test, the mixing rate of small coke was determined in the central part of the equipment, which is not affected by the wall effect, and in the radial direction.
The resin was kneaded with a curing agent at a point and poured in, and the sample was sampled without disturbing the deposited structure of the sample. The results obtained from the observation of the cross section are shown in FIG. In Fig. 5, A indicates the central part of the device, and B
shows the test results for the inner wall of the device. The vertical and horizontal axes in FIG. 5 are defined as follows. Dimensionless small coke mixing ratio = Small coke mixing ratio at that position (%) / Small coke mixing ratio assuming uniform mixing (%) Dimensionless height direction position = Vertical distance from the bottom of the ore layer (m
)/Ore layer thickness at that location (m)

【table】

[Table] In the conventional method (Fig. 2), small coke is unevenly distributed near the surface of the ore layer, and in the conventional method (Fig. 3), small coke is unevenly distributed near the boundary between the initial charging ore and the final charging ore. It can be seen that small coke is unevenly distributed. On the other hand, in the present invention, the uneven distribution of small coke in the height direction is almost eliminated, especially in the central part, and even in the furnace wall, the mixed ratio of small coke peaks in three places: the bottom, the middle, and the surface layer. The uneven distribution is much suppressed compared to the conventional method, which has a peak at one location. In this way, if the method of the present invention is used, there is no need to mix small coke into the ore layer before charging into the blast furnace, so there is no need to take measures to prevent uneven distribution in the storage tank, which not only reduces equipment costs but also eliminates the need to take measures to prevent uneven distribution in the storage tank. In the blast furnace, it is possible to mix small coke in the ore layer without unevenly distributing it, and it is possible to operate the blast furnace in which small coke can be stably used.

[Brief explanation of the drawing]

FIG. 1 is a raw material distribution diagram in the furnace when small coke is mixed and charged into an ore layer according to the method of the present invention. Figure 2 is a raw material distribution diagram in the furnace when small coke is mixed and charged into an ore layer using the conventional method. Figure 3 is a raw material distribution diagram in the furnace when small coke is mixed and charged in the ore layer using the conventional method. Figure 4 shows the large bell of charged ore from the second time onwards.
Deposition map of Hotupa and Belres Bangka.
Figure 5 is a distribution diagram of the mixing ratio of small coke in the ore layer in the conventional method and the method of the present invention in a full-scale model test. 1...Blast furnace, 2...Lump coke, 3...Small coke, 4,4',4''...Ore, 5...Large bell,
6...Large bell fixed wall, 7...Bellless banca,
8...Gate valve, 21...Lump coke slope.

Claims (1)

[Claims] 1 When charging raw materials into the blast furnace, the coke should be charged in parts, small coke should be used as the final coke charge, and the small coke should be placed near the position where the initially charged ore falls into the furnace. The ore should be charged in parts, the ore should be charged in parts, the ore should be charged only at the initial stage of ore charging, and the ore should be charged in the lower part of the large bell hoppa or bellless banka during the second or subsequent charging. A method for charging raw materials for a blast furnace, which consists of depositing small coke, depositing ore on top, and charging into the furnace at the same time.