JPH0314883B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of charging raw materials into a blast furnace in the steel industry, and more particularly, to a method of uniformly mixing a plurality of raw materials having irregular shapes and different particle sizes and charging the mixture into a blast furnace.

As is well known, in blast furnace operation, the particle size distribution of the raw materials such as ore, coke, and other charges in the radial direction of the furnace is one of the main factors governing stable operation, along with the fuel ratio, due to its ventilation resistance. It is.

In recent years, various types of ores have been used due to raw material conditions, such as sintered ores, pellets, lump ores, etc., and these are appropriately mixed and charged into a blast furnace. The physical properties of these ores are, for example, sintered ores, and lump ores have angular and irregular shapes, but pellets have a spherical shape with a smooth surface. In addition, the particle sizes are significantly different: sintered ore is 24mm, pellets are 11mm, and lump ore is 14mm (average particle size for each).

Therefore, unless these ores are mixed evenly and have a uniform particle size before being charged into the furnace, it will be impossible to properly control the radial distribution in the furnace as described above. It is something.

To explain a conventional method of charging such various kinds of ore raw materials into a blast furnace, as shown in FIG.
B. The lump ore hopper 1C cuts out the lump ore to the belt conveyor 3 by each cutting device 2, and transports it block by block as sintered ore 4a, pellets 4b, and lump ore 4c, and charges it into the surge hopper 5 in layers. stored. The various stored raw materials are cut out onto a belt conveyor 7 by a cutting device 6 and transported to the top of the furnace in a mixed state. On the other hand, coke, which is a reducing agent, is cut out from a coke hopper 8 through a cutting device 9 to the belt conveyor 7, and via a switching chute 10, ores are stored in a storage hopper 11, coke is stored in a storage hopper 12, or both are stored. Ores and coke are stored alternately in hoppers 11 and 12, and are cut out alternately while being controlled by a flow rate regulating gate valve 13. Reduction ventilation is maintained in the radial direction inside the furnace by a rotating chute 14 inside the furnace. The ore and coke are distributed and charged in layers to ensure good quality.

However, such a charging method has the following drawbacks. That is, when temporarily storing in the surge hopper 5 and the storage hoppers 11 and 12 at the top of the furnace, if the particles are dropped from the belt conveyor and deposited in the hoppers, particles with large diameters fall far away, and particles with small diameters Small objects fall nearby. In addition, in the process of being deposited in the hopper, △ peaks are formed, and large diameter particles roll over a large amount, so they accumulate in the circumferential direction along the wall, while small diameter particles accumulate in the center of the △ peaks. Percolation Pellets, in particular, have a smooth surface and are spherical, so they roll a lot, so most of them are deposited on the circumference of the wall. In this way, the gas segregates in the surge hopper and is cut out in a state where the segregation is amplified in the storage hopper at the top of the furnace, making it difficult to control the gas flow even if the distribution is controlled in the radial direction in the furnace using a rotating chute. It is something.

In view of these circumstances, the present invention provides a method for storing a plurality of raw materials of irregular shapes and different particle sizes in a storage hopper at the top of the furnace so as to uniformly mix them, and charging the raw materials into the furnace. The feature is that various raw materials are stacked in a predetermined ratio on a belt conveyor from each raw material hopper and transported to the storage hopper at the top of the furnace and dropped in a mixed state, and as a method to prevent segregation in the storage hopper. The material is charged and stored through a charging tube and a rectification/distribution mechanism, and then charged into the furnace.This method allows each raw material and particle size to be mixed uniformly, so there is no problem in the furnace. The charging distribution can be easily controlled in the radial direction using the rotating chute.

The method of the present invention will be specifically explained below with reference to Examples.

First, the method of cutting out various raw materials in layers at a predetermined ratio onto a belt conveyor from each raw material hopper is as shown in FIG. with a difference in the height direction, belt conveyor 3
When loading on top, the sintered ore 4a is cut out in a layered manner, followed by pellets 4b at the bottom, and lump ore 4C at the top, loaded and transported to the top of the furnace. When the raw materials are dropped from the conveyor 3 in such a loaded state, the various raw materials are evenly mixed and dropped.

The method of charging the material into the storage hopper 11 is to drop it through the charging tube 15 via a switching chute (not shown) as shown in FIG. That is, the purpose of passing through this charging tube is to prevent particles with large diameters from scattering far and to allow them to fall in a mixed state. Charging cylinder 15
A rectifying and distributing mechanism is further provided below the center core. The rectification/distribution mechanism is a cylindrical rectification cylinder 16 with an open top and bottom, and the raw material falling from the charging cylinder 15 is first
The raw material that overflows from the rectifying tube 16 enters the rectifying tube 16 and plays a rectifying role, flows out from below and is deposited as shown in (b). ), it flows in and hardly forms a Δ peak, and therefore, even large particles or spherical pellets do not roll, making it possible to prevent segregation and allowing them to be stored in a mixed state. Incidentally, it is preferable to appropriately narrow down the lower end portions of the charging tube 15 and the straightening tube 16 because the respective effects are more effectively exhibited.

Another embodiment of the rectifying and distributing mechanism will be described. As shown in FIG. 4, a donut-shaped rectifying plate 17 is provided below the center of the charging tube 15. The raw materials that fall from the charging tube 15 and fall through the holes in the rectifier plate 17 are deposited as shown, and the raw materials that hit the plate fall in the circumferential direction as shown, and do not form △ mountains, so segregation can be prevented. It is something.

The raw materials charged in this way and the raw materials charged by the conventional method explained above were cut out from the storage hopper and the results of investigating how much of each raw material was evenly charged from the rotating chute in the furnace are shown in Figure 5. Shown below.

In FIG. 5, the vertical axis represents the proportion of each raw material in the total amount discharged, and the horizontal axis represents the cumulative amount discharged. SO is sintered ore, P
SL indicates pellets and SL indicates lump ore, solid lines indicate examples of the present invention, and dotted lines indicate comparative examples. As is clear from this figure, in the conventional method, each raw material was segregated to a wide extent, but in the method of the present invention, each raw material is charged into the furnace at the desired ratio without causing almost any segregation. is clear. In this embodiment, charging into the furnace was explained using a rotating chute, but it goes without saying that bell-type charging is also applicable. In addition, when using a conventional surge hopper, the surge hopper is equipped with a charging tube and a rectification/distribution mechanism, and each raw material loaded in layers is charged into the surge hopper, mixed and stored uniformly, and then cut out in a mixed state. It is more effective and preferable to charge the materials into the storage hopper at the top of the furnace using a belt conveyor because uniform mixing can be achieved in two stages.

As explained in detail above, the method of the present invention has the advantage that the purpose can be achieved by simply improving the cutting device for each raw material, and by simply adding a simple mechanism to the storage hopper of the conventional hopper. Moreover, since each raw material and particle size are mixed uniformly, the gas flow can be easily adjusted by controlling the charging distribution in the radial direction using the rotating chute inside the furnace, which greatly contributes to stable operation of the blast furnace and a reduction in the fuel ratio. This is an excellent invention that can contribute.

[Brief explanation of drawings]

Fig. 1 is a system diagram of charging raw materials into a blast furnace to explain a conventional example, Figs. 2 to 5 are illustrations of embodiments of the present invention, Fig. 2 is a side view of raw material cut out from a raw material hopper, and Fig. 3 Figure 4 is a front cross-sectional view of the furnace top storage hopper.
FIG. 5 is a diagram showing the relationship between the total discharge amount of the storage hopper, the proportion of each raw material, and the cumulative discharge amount. 1A, 1B, 1C... Raw material hopper, 2, 6,
9... Cutting device, 3, 7... Belt conveyor, 4
a, 4b, 4c...Charging raw material, 5...Surge hopper, 8...Coke hopper, 10...Switching chute, 11, 12...Furnace top storage hopper, 13
...Flow control gate valve, 14...Swivel chute,
15... Charging tube, 16... Rectifying tube, 17... Rectifying plate.

Claims (1)

[Claims] 1 In a method of charging a plurality of ore raw materials with irregular shapes and different particle sizes into a furnace, various raw materials are stacked at a predetermined ratio on a belt conveyor from each raw material hopper and transported to the top of the furnace. It is characterized by charging into the storage hopper through a charging tube provided in the upper center of the storage hopper and a rectification/distribution mechanism provided below the core of the charging tube, storing it in the same hopper, and then charging it into the furnace. A method of charging raw materials into a blast furnace.