JPH0154403B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method for disintegrating a reduced solid iron powder cake into product iron powder having a desired apparent density. This invention relates to a coarse pulverization method for coarsely adjusting particle size by crushing and pulverizing.

[Conventional technology]

Generally, iron powder pulverization equipment coarsely and finely granulates a solid iron powder cake that has been reduced in a reduction furnace into a product iron powder with the desired apparent density and particle size distribution, and then vibrates it. This is equipment for sifting products using a sieving machine, and mainly consists of a primary disintegrator and a secondary disintegrator.

The above-mentioned primary crusher is a device for coarsely adjusting the particle size by crushing and crushing the iron powder cake conveyed by a steel belt. Generally, a crushing hammer is attached so as to be swingable, and the rotor is rotated at a predetermined speed.

In addition, the above-mentioned secondary pulverizer uses iron powder that has been coarsely pulverized in the primary granulator, finely granulates it in a feather mill to make the particle size uniform, and then passes it through a vibrating sieve to separate over powder and under powder. This is a device for separating the underpowder into two parts and recovering this underpowder as a product. Note that the above-mentioned oversized powder is re-pulverized by the feather mill in the next step, and then sieved.

By the way, the purpose of the above-mentioned primary pulverizer is to coarsely granulate the iron powder in advance so that it can be easily and reliably pulverized to the apparent density required by the secondary granulator.
Moreover, since the apparent density of the product iron powder depends on the degree of pulverization in the primary pulverizer, it is necessary to be able to coarsely pulverize the iron powder to a density that corresponds to each required apparent density, from high density to medium density to low density. .

Conventionally, in order to ensure the degree of coarse granulation that corresponds to the required apparent density of product iron powder, the primary granulator was replaced with a granulator suitable for high density powder, medium or low density powder, for example. Ta.

[Problem that the invention seeks to solve]

However, with the above conventional equipment, when finely disintegrating into high, medium, and low apparent density powders using a secondary disintegrator, the primary disintegrator is used as a disintegrator according to the required degree of coarse disintegration. Since the equipment is replaced, it is necessary to stop the equipment during this replacement, which poses a problem in that productivity decreases accordingly. Furthermore, the conventional primary disintegrator has the problem that it is not possible to adjust the disintegration in response to changes in the properties of black powder (iron powder before reduction treatment) or changes in the conditions of the reduction furnace, even for the same type of steel.

The present invention was made in order to solve the above-mentioned conventional problems, and the primary disintegrator can be used even when disintegrating graphite to different apparent densities or when the properties of graphite or furnace conditions change. The object of the present invention is to provide a method for coarsely pulverizing iron powder cake in iron powder granulating equipment that does not require replacement and can improve productivity.

[Processing to resolve the problem]

Therefore, the present invention provides iron powder pulverization equipment in which a solid iron powder cake extracted from a reduction furnace is coarsely and finely granulated using primary and secondary granulators, in which a casing is used as the primary granulator. The iron powder cake is coarsely granulated by the impact energy of the pulverizing hammer generated by rotating the rotor at a variable speed. A variable speed rotary hammer-type granulator is adopted, and the rotation speed of the granulator is controlled so that the required apparent density of the product iron powder in the secondary granulator increases as the density increases, and decreases as the density decreases. This is a method for coarsely pulverizing an iron powder cake, which is characterized in that the iron powder cake is rotated at a variable speed.

In the method of the present invention, for example, a characteristic curve representing the relationship between the rotational speed of the disintegrating hammer of the primary disintegrator and the apparent density of the product iron powder obtained in the secondary disintegrator is determined in advance through experiments. It is desirable to use this characteristic curve to calculate the speed of the disintegrator hammer that can achieve the required apparent density, and to control the speed of the primary disintegrator using this speed as a target.

Furthermore, since the primary disintegrator of the present invention is a method of coarsely disintegrating the iron powder cake using the impact energy generated by the rotation of the disintegrating hammer, as described above, the variable speed rotary hammer type It is necessary to adopt a granulator. However, the type and structure of the secondary pulverizer are appropriately selected depending on the required apparent density of the product iron powder, etc., and there is no need to limit them.

[Effect]

According to the method for coarsely pulverizing iron powder cake in the iron powder granulating equipment according to the present invention, the rotation speed of the primary granulator is changed, so that coarse granulation can be achieved according to the required apparent density of the product iron powder. The secondary disintegrator can produce high-density powder or medium or low-density powder as desired, and there is no need to replace the primary disintegrator depending on the required apparent density as in the past. Therefore, productivity can be improved by the time required to replace the primary disintegrator. Furthermore, since the rotational speed of the primary disintegrator can be freely changed, disintegration can be adjusted in response to changes in the black powder properties and the furnace conditions of the reduction furnace.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

1 to 5 are diagrams for explaining a method of coarsely pulverizing an iron powder cake in an iron powder pulverizing equipment according to an embodiment of the present invention.

First, the iron powder crushing equipment for carrying out the method of this embodiment will be explained. In the figure, 1 is a primary crushing equipment for coarsely crushing the solid iron powder cake that has been reduced in a reduction furnace (not shown);
A variable speed granulator 4 as a primary granulator, which will be described later, is installed at the bottom of a chute 3 disposed at the end of the steel belt 2, and extends horizontally to a discharge chute 4a of the granulator 4. It is constructed by connecting a horizontal transfer lift 5 and a vertical transfer lift 6 to the transfer lift 5, respectively.

7 is a secondary disintegration equipment for finely disintegrating and classifying the coarsely disintegrated iron powder. Connected buffer hopper 10
A vibrating feeder 11 is disposed at the bottom of the buffer hopper 10 via an expansion joint 9, and a feather mill 12 as a secondary crusher is connected to the vibrating feeder 11. A vibrating sieve machine 13 is connected to the vibrating sieve machine 13 via an expansion joint 9.

In addition, the upper sieve tub 1 of the vibrating sieve machine 13
A 90-mesh screen is installed between the upper sieve tub 13a and the upper sieve tub 13a, and an over powder collection pipe 14a is connected to the upper sieve tub 13a, and the end of the collection pipe 14a is connected to an over powder vibrating conveyor. 15, and further connected to the lower sieve tub 1.
3b is connected to an under powder collection pipe 14b, and the end of the collection pipe 14b is connected to the under powder vibrating conveyor 1.
6.

In addition, 20 is a recovery hopper for recovering the sifted under powder as product iron powder, 21 is a re-pulverizing device for re-pulverizing the above-mentioned over-pulverizing powder, and 22 is a re-pulverizing device for re-pulverizing the above-mentioned over powder. This is an over-flour processing device for processing the over-flour produced for other purposes.

The variable speed granulator 4 has a plurality of granulating hammers formed by forming a granulating surface in the rotational direction of the rotor 23 on the outer peripheral surface of a rotatable cylindrical rotor 23 disposed in a casing 25. 24 is fixed. A hammer speed control device 28 is connected to the drive device 27 of the rotor 23, and this control device 28 adjusts the rotational speed of the rotor 23 to the required apparent density of the product iron powder in the secondary crushing equipment 7. It is configured to freely control the rotation speed according to the rotation speed.
That is, this control device 28 stores an apparent density-rotational speed map as shown in FIG. The drive device 27 is also controlled at the rotational speed V. The above map was determined in advance through experiments depending on the properties of the iron powder to be treated.

Next, a case will be described in which the method of this embodiment is implemented using the above-mentioned apparatus.

The plate-shaped iron powder cake conveyed by the steel belt 2 is divided in the chute 3 and guided into the variable speed crusher 4, where it collides with the repulsion plate 26 by the rotational force of the crusher hammer 24. It will be coarsely granulated into powder. In this case, the required apparent density S of the product iron powder, for example 2.8 g/cc, is determined by the control device 28.
When the input is inputted to It is rotated at a speed corresponding to the required apparent density. In addition, if the required apparent density becomes even higher, the above-mentioned crushing hammer 2
The rotation speed of No. 4 is increased according to the required apparent density, and conversely, when low density is required, the rotation speed is lowered.

The coarsely pulverized iron powder is transferred by conveyors 5, 6, and 8, and is transferred to a buffer hopper 10.
Feather mill 12 is generated by vibration feeder 11 from inside.
The powder is further pulverized there, and then sieved by a vibrating sieve 13 into over powder and under powder. The under powder at this time is collected in the recovery hopper 20 as product iron powder, and the over powder is transferred to the re-crushing device 21 where it is re-cracked and classified. The powder is transferred to the over powder processing device 22.
The iron powder is then transported to the factory, where it is re-pulverized to produce iron powder for secondary purposes.

As described above, according to the coarse granulation method according to the present embodiment, since the rotation speed of the variable speed granulator 4 is changed, coarse granulation can be performed according to the required apparent density of the product iron powder. Feather mill 1 of secondary crusher
Since high-density powder or medium- or low-density powder can be obtained as desired by 2, there is no need to replace the primary disintegrator depending on the required apparent density as in the conventional method. Therefore, the operating rate of the equipment increases by the amount of time required to replace the primary disintegrator, and productivity can be improved. Furthermore, since the rotational speed of the variable speed granulator 4 can be freely changed, granulation can be adjusted in response to changes in the black powder properties and the furnace conditions of the reduction furnace.

〔Effect of the invention〕

As described above, according to the method for coarsely pulverizing iron powder cake in iron powder pulverizing equipment according to the present invention, the rotational speed of the primary granulator can be adjusted to the required apparent density of the product iron powder in the secondary granulator. Accordingly, the value is changed so that it is high for high density and low for low density.
It is no longer necessary to replace the primary crusher as in the past.
This has the effect of improving productivity.

[Brief explanation of drawings]

1 to 5 are diagrams for explaining a method for coarsely pulverizing an iron powder cake in an iron powder pulverizing equipment according to an embodiment of the present invention, and FIG. 1 is a schematic configuration diagram thereof, and FIG. is a schematic diagram showing the iron powder transfer process,
Fig. 3 is a sectional view showing the variable speed granulator, Fig. 4 is a block diagram thereof, and Fig. 5 is the rotational speed of the variable speed granulator stored in the hammer control device and the appearance of the product iron powder. It is a map diagram showing the relationship with density. In the figure, 4 is a variable speed granulator (primary granulator);
12 is a feather mill (secondary crusher), and 24 is a crusher hammer.

Claims (1)

[Claims] 1. The plate-shaped iron powder cake solidified in the iron powder reduction furnace is coarsely granulated by a primary granulator, and then finely granulated into product iron powder with a desired apparent density by a secondary granulator. A method of coarsely granulating an iron powder cake using the above-mentioned primary granulator in an iron powder granulator, wherein the primary granulator is a rotor disposed in a casing so as to be able to be driven at a variable speed. A variable speed rotary hammer-type granulator is adopted in which the hammer is swingably attached and the iron powder cake is coarsely granulated by the impact energy of the granulating hammer generated by rotating the rotor, and the granulating hammer is In the iron powder pulverizing equipment, the rotation speed is variable so that the required apparent density of the product iron powder in the secondary pulverizer is higher as the density is higher and lower as the density is lower. Coarse granulation method for iron powder cake.