JPS59127639A - Pre-treatment of stock material being sintered - Google Patents

Abstract

PURPOSE:To improve the ventilation property of a stock material layer in a sintering process, by temporarily staying a powder stock material by providing a weir to the machine wall of the intemediate part in the axial direction of a cylindrical granulator while performing forcible stirring by the rotor arranged in said staying region. CONSTITUTION:Moisture is added to a powdery stock material to be sintered which is supplied to the cylinder 1 of a rotary cylindrical mixing granulator while delivered to a belt conveyor 3 from a water supply nozzle 4 and advanced through a kneading part S and a granulating part W while mixed in the cylinder 1. On the way of advance, the staying amount of the powdery stock material passing the kneading part S ranging from a weir 12 provided to the machine wall at the intermediate part in the axial direction in the cylinder 1 to the inlet part by said weir 12. A kneading rotor 9 is arranged to the stay amount increased part and moisture is uniformly adhered to the stock material while uniformly kneading the same by the rotor 9. After kneading, the stock material overflowing the weir 12 is granulated while rolling the granulation part W.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in the method of mixing and granulating powder raw materials for sintering.

Sintered ore, the main raw material for blast furnaces, is generally manufactured through the following process. That is, milled raw materials such as powdered ore and limestone powder, and powdered fuel such as coke powder (together referred to as powdered raw materials) are mixed in an inclined rotating cylindrical mixing granulator such as a drum mixer to form pseudo particles. The sintering machine is charged with granulated pseudo-particles of fc, ignited the powdered fuel such as coke powder on the surface of the charged layer, and sucks air from below.
The sintering reaction progresses from the top to the bottom, producing sintered ore.

The rate and uniformity of the sintering reaction are greatly influenced by the permeability of the charging layer in this sintering machine, and the better the permeability of the charging layer, the better the quality of the produced sintered ore. It is said that the production speed is also high. The conditions for a charging layer with good air permeability are that the pseudo particles that are generated in the granulator and forming the charging layer do not lose their shape even when subjected to mechanical impact at room temperature, and that the sintered paddy does not lose its shape when the temperature is raised. In the production of pseudo-particles, the particles do not lose their shape even when subjected to thermal shock, and the particle size of the produced particles is uniform. : There are few.

However, as shown in Figure 1, conventionally the rotation was made using a cylindrical mixed
While rotating the cylinder 1 of a drum mixer (drum mixer) with a drive device 5, powdered raw material cut out from a raw material charging hopper 2 is supplied to the cylinder 1 by a belt conveyor 3, and water is removed from a water supply nozzle 4 at the entrance of the cylinder 1. is sprinkled onto the powder raw material 7 to adjust the moisture content to a desired ratio, and as it rotates inside the cylinder, the powder raw material layer is reversed.

The core particles descend while rolling, and during this time fine particles of the powder raw material adhere to the core particles to produce pseudo-particles, which are discharged from the cylinder onto the discharge conveyor 6, thus producing pseudo-particles. Although a considerable number of pseudoparticles produced by this method have properties that satisfy the above conditions, there are also a considerable number of pseudoparticles that do not satisfy the above conditions, and it is possible for fine particles to remain after production! ll, and these improvements were required.

In addition, FIG. 2 is a sectional view taken along the line A-A in FIG. 1, and 8 is a powder raw material scraping plate.

Therefore, an object of the present invention is to provide a method for pre-processing a sintering raw material to produce pseudo-particles that can satisfy the above-mentioned conditions, thereby improving the permeability of the raw material layer during the sintering process, This contributes to improving the quality of sintered ore and productivity.

The present invention is characterized by a weir installed on the machine wall in the axially intermediate part of an inclined rotary cylindrical mixing granulator, such as a drum mixer, which produces a pseudo-granule as a raw material for sintering. A mixing line turning body without stirring blades, which temporarily retains the moving powder raw material using a stirring blade, and is provided in the temporary retention area of the powder raw material.
or forcibly stirring the stagnant powder raw material while imparting rotational motion in the same or opposite direction to the rotational direction of the mixing granulator using a mixing rotor equipped with a stirring blade; The granulation is mainly carried out at the rear of the weir, and the pseudo-granulation characteristics of the F sintering raw material can be significantly improved.

According to the investigation and research carried out by the present inventors, when the powder raw materials are humidified at the inlet of a drum mixer etc. to adjust the moisture content to around 4-8% and then mixed and granulated, the water is It has been found that by forcibly kneading and stirring the powder raw materials, water can be uniformly attached to the surface of each fine particle of the powder raw materials. This adhered water acts to increase the bonding force between particles by exerting a capillary suction force even when fine particles come into contact with other particles. , in the granulation process of pseudoparticles, around the core particle,
Most of the fine particles with adhering water are bonded together with strong force, so there are few remaining fine particles, and almost all of the pseudo particles are relatively disintegrated, resulting in K-like properties, and when sintered using this raw material, It was found that sintered ore with good productivity and excellent quality could be obtained.

The present invention will be explained below based on five examples.

FIG. 2(a) is a side sectional view showing an example of an inclined rotary cylindrical mixing granulator for explaining the present invention;
b) The figure is a cylindrical sectional view taken along the line B-B' in Figure aJ.

The sintered coarse powder raw material is cut out from the raw material charging hopper -2 to the belt conveyor 3 and supplied to the rotary cylindrical mixed granulation type cylinder 1. Moisture is added from the water supply nozzle 4, and after the humidity is adjusted, the sintered coarse powder raw material is rotated. In the middle of the rotary cylindrical mixing granulator, a weir 1 is installed on the axially intermediate wall of the cylinder 1 of the rotary cylindrical mixing granulator.
2, the retention amount of the powder raw material passing through the cross-conducting part S from the weir 12 to the inlet part increases, and a cross-conducting rotary body 9 is installed in the part where the retention amount increases, and this rotary body The raw materials passing through are kneaded more uniformly, and moisture is evenly attached to them, compared to the conventional cross-mixing method simply caused by the rotation of the cylinder. After cross-mixing, the powder raw material overflowing the weir 12 rolls through the granulating section W of the cylindrical mixing granulator, and is granulated with moisture-adhered fine particles firmly attached to the core particles, and finally into the cylindrical mixing granulator. It is discharged from the rear of the granulator. The rotating direction of the cross-conducting rotating body 90 installed in this cylindrical mixing granulator may be the same as or opposite to the rotating direction of the cylindrical mixing granulator, and the position of the rotating body 9 is as shown in FIG. It is sufficient that at least a part of the raw material 7 remaining in the fertilized material 7 is fertilized.

In Fig. 2, 8 is a raw material scraping board, 7f'i powder raw material layer,
5 is a cylindrical mixing granulator drive device, 10 is a drive device for the rotating body 9, 11 is a rotating body bearing support rod, and 6 is a discharge belt conveyor.

The granulation effect in the granulator to which the method of the present invention is applied, in which the inside of the rotary cylindrical mixing granulator is divided into a part mainly for kneading and a part mainly for granulating, will be explained below.

Pseudo-particles were made using the rotary cylindrical mixing granulator shown in Fig. 2, and the granulation state was determined using the granulation index G, I (0.5ran
) and shown in Figure 3. Here, the granulation index G.

■. (0,5tin) is expressed by the following formula.

G.1. The (0,5 bleaching) index 2, ie, the above formula, indicates the proportion of fine particles with a particle size of 05 mm or less adhering to particles with a particle size of 0.5 mm or more. Therefore, this G
The higher the I (0,5wn) index, the more particles will adhere to the core particles and the fewer particles will remain. Third
As can be seen from the figure, the method of granulating by installing a weir inside the cylindrical mixing granulator to increase the retention amount of powder raw materials and installing a rotating body for kneading has a high G, I (0,5wn) index. , indicating that the proportion of remaining fine particles is low.

In order to prove this, we used the sintering experimental apparatus shown in Figure 4.
A test regarding sinterability was conducted. The raw material was charged into the sintered steel 14 and ignited in the ignition furnace 13, then the ignition furnace was removed and air was sucked downward for sintering. In the figure, 15 is a sintered layer, 16 is a grate, and 17 is a nozzle.

Air permeability and productivity in this experiment will be explained next.

Figure 5 shows the permeability of the raw material packed bed before sintering (constant pressure (-5
The passing wind speed of the raw material layer according to the present invention is approximately 05 m/S higher than that of the conventional method, indicating that the air permeability is improved.

FIG. 6 shows the productivity when sintering is carried out using the apparatus shown in FIG. 4. By using the raw material granulated according to the present invention,
Productivity has improved, and the effect of the method of the present invention is remarkable.

As described above, according to the method of the present invention, the powder raw material and water are mixed uniformly throughout the powder raw material, and therefore, the mechanical strength is weak, the powder is susceptible to thermal shock, and there are fewer pseudo particles with non-uniform particle size. The number of fine particles generated in the layer is reduced, the granulation property is improved, and the number of remaining fine particles is reduced.As a result, the air permeability of the sintered layer is improved, and the productivity is improved.

In addition, one or more rotating bodies for crosstalk installed in the rotary cylindrical mixing granulator may be attached to the same shaft, or multiple rotating shafts for crosstalk may be installed in parallel, and one or more rotary bodies for crosstalk may be installed on the same shaft. A rotating body for crosstalk may be provided. This is selected depending on the scale of the rotary cylindrical mixing granulator, raw material residence time, target granulation properties, etc. FIG. 7 shows a cylindrical cross-sectional view of a mixing granulator, which is an example of a case in which a plurality of rotating shafts for crosstalk are provided in parallel.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram of the conventional method, Figure 2 is an example of a rotary cylindrical mixing granulator to which the method of the present invention is applied, and Figure 3 is the G of granules produced by the conventional method and the method of the present invention. , I index comparison diagram, Figure 4 is a cross-sectional view of the sintering experimental equipment, Figure 5 is a comparison diagram of granule permeability between the conventional method and the method of the present invention, and Figure 6 is a comparison diagram of sintering productivity. FIG. 7, which is a comparison diagram of the conventional method and the method of the present invention, is a partial explanatory diagram of another embodiment to which the method of the present invention is applied. In the figure, 1...Rotating cylindrical mixed granulation-like cylinder, 2...
Raw material charging hot ξ-53 -- Belt conveyor, 4.
...Water supply nozzle, 5... Rotating cylindrical mixing granulator drive device, 6... Discharge belt conveyor, 7... Raw material layer, 8... Raw material scraping plate, 9... Rotating body, 10...
Rotating body drive device, 11...Rotating body bearing support rod, 1-2
...weir. Agent Patent Attorney Masa Aki Sawa Mitsugai 2 Needle 3 Diagram "A4 Diagram 71" 7 Diagram

Claims (1)

[Scope of Claims] (υ When continuously mixing and granulating powder raw materials using a tilted rotary cylindrical granulator, a A weir is used to temporarily retain the moving powder raw material. A mixing rotary body disposed in the temporary retention area of the powder raw material is used to forcibly stir and granulate the staying powder raw material. A method for pre-processing raw materials for sintering.