JP2658671B2 - Method and apparatus for mixing and granulating raw materials - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for mixing and granulating raw materials in which multiple (multiple sets) of raw materials are granulated simultaneously using a multi-cylindrical tube having a concentric cross section.

[0002]

2. Description of the Related Art Conventionally, in a pre-treatment step for producing a sintered ore by firing a powdery iron ore (fine ore), various raw materials such as lime powder and coke fine are mainly used in the fine ore. Are mixed and water is added to perform granulation. Further, slaked lime or quick lime may be added as a binder.
In some cases, dust generated in steel works is used as an iron source.

As described above, in the production of sintered ore, generally various miscellaneous raw materials are subjected to granulation at once and used as a raw material for sintering. Along with performing the granulation process separately for several types of raw materials,
A composite granulation process has been developed to improve the quality of sinter ore and reduce the firing energy. For example, a two-stage sintering method in which a raw material with high coke is charged into the upper layer of the sintering pallet and a raw material with low coke is charged into the lower layer, or a granulated material mainly composed of limestone having a high CaO content and a low Separate granulation method in which granulated CaO components are separately granulated, then mixed and fired, or divided into two or more raw materials in advance according to the difference in water absorption of the raw ore, and the water content is adjusted so that each has the optimum water content. And granulating them separately, followed by mixing and firing. However,
In any of these processes, at least one mixing and granulating apparatus (mixer) is required for one granulating step, and a number of granulating machines or a number exceeding the number of types of raw materials to be granulated are installed.

[0004] In other words, the use of the composite granulation process as described above makes it possible to improve the quality of the sintered ore and reduce the firing energy, but requires many granulators, and requires equipment cost and cost.
There are various problems such as an increase in an installation place and an increase in energy required for granulation, and this is an obstacle to the spread of such a composite process.

[0005] Further, even if an attempt is made to utilize equipment that is already in operation, the processing capacity for mixing a plurality of granulated materials by the above-described divided granulation is limited by the existing mixer that granulates all the raw materials at once. There is also a drawback that the processing capacity is exceeded and it is difficult to use existing equipment.

On the other hand, as a mixing granulating apparatus, a pagmill,
Dish-type pelletizers, drum-type granulators, Erich mixers, etc. are used, but drum-type granulators (drum-type mixers) that use inclined rotating cylindrical tubes with particularly high production efficiency
Are widely spread. In this drum-type mixer, the raw materials such as ore and the like are repeatedly rolled in the rotating drum, and the raw materials are mixed to perform granulation.

FIG. 3 (a) is a schematic longitudinal sectional view showing an example of a conventional drum type mixer using an inclined rotary cylindrical tube, in which an outer cylinder (drum) 2 rotating from a raw material hopper 1 is shown. The raw material 6 charged into the container is added with an appropriate amount of water from the water injection nozzle 3, mixed and granulated while moving to the discharge end 19 while rolling in the outer cylinder 2, and discharged from the discharge end 19. . The outer cylinder 2 is slightly inclined with the discharge end 19 facing downward. FIG. 3B is a sectional view taken along the line BB of FIG.
The rolling state of the raw material 6 in the outer cylinder 2 is shown.

In producing a sintered ore, a drum mixer used for granulation is usually operated at a diameter of 2 to 5 m, an inclination angle of about 1 to 5 degrees, and a rotation speed of about 5 to 10 rpm. I have. In this granulation process, the ratio of the raw material to the space in the drum (occupation ratio) is usually about 10% because the mixing and granulating action of the raw material in the cylinder is reduced if it is too large. 90% of the space is not used at all. In addition, the larger the diameter of the mixer, the longer the rolling distance of the raw material and the improved the granulation performance. However, there is a drawback that the equipment becomes large and the required power increases.

[0009]

SUMMARY OF THE INVENTION According to the present invention, when mixing and granulating powdery raw materials such as fine ore by a drum type mixer, many types (many sets) of raw materials are simultaneously granulated by one mixer. It is another object of the present invention to provide a method and apparatus for mixing and granulating raw materials, which can improve space utilization and improve granulation efficiency with the same capacity as a conventional drum mixer.

[0010]

The gist of the present invention resides in a method for mixing and granulating the following raw materials and an apparatus for mixing and granulating the following raw materials.

A multi-cylindrical tube composed of a plurality of cylindrical tubes connected to each other so as to form concentric circles is rotated around the central axis of the cylindrical tube while being inclined with respect to the horizontal level in the moving direction of the raw material. The method is characterized in that various kinds of powdery raw materials having different properties are charged from one end of the multi-cylindrical tube into each section divided by each cylinder of the multi-cylindrical tube, and are moved to the other end while rolling. Granulation method of raw materials to be used.

[0012] The above method for mixing and granulating raw materials, wherein the difference in properties of the powder raw materials is the concentration of the CaO component.

The multi-cylindrical tube is a double-cylindrical tube, and the difference in the properties of the powder raw material is the concentration of the CaO component, and the raw material of the high CaO component is placed in the cylinder inside the double-cylindrical tube, and the low CaO component is The raw material mixture is charged between the inner cylinder and the outer cylinder of the double cylindrical tube.

A cylindrical tube having a downward inclination in the moving direction of the raw material with respect to the horizontal level and rotatably supported;
A raw material hopper for charging a raw material to the end of the cylindrical tube, and a raw material mixing and granulating apparatus provided with a water injection nozzle for adding water to the charged raw material, wherein the cylindrical tube has It is a multi-cylindrical pipe composed of a plurality of cylindrical pipes connected to each other so that their cross-sectional shapes form concentric circles, and a raw material hopper and a water injection nozzle are provided for each section divided by each cylinder of the multi-cylindrical pipe. Characteristic mixing and granulation equipment for raw materials.

In the above apparatus, the first half of the raw material charging side of the cylindrical pipe is a multi-cylindrical pipe composed of a plurality of cylindrical pipes connected to each other so that the cross-sectional shapes thereof form concentric circles. Mixing of raw materials is provided for each section divided by each cylinder of the multi-cylindrical pipe, and the rear half of the cylindrical pipe on the raw material discharge side comprises only the pipe having the largest diameter among the multi-cylindrical pipes. Granulation equipment.

[0016]

The method and apparatus for mixing and granulating raw materials of the present invention will be described below with reference to the drawings.

FIG. 1A is a longitudinal sectional view showing the structure of an example of a mixing granulation apparatus for carrying out the present invention (the invention). This figure is an example of a drum type mixer having a double tube structure, wherein 2 is an outer cylinder, 9 is an inner cylinder, and both cylinders are arranged so as to share the central axis 5. Reference numeral 8 denotes a support rod for fixing the inner cylinder 9. On the raw material charging side of the double cylindrical tube, a portion divided by the inner cylinder 9 and the outer cylinder 2, that is, a portion inside the inner cylinder 9 and a portion outside the inner cylinder 9 (hereinafter, referred to as inside the outer cylinder 2). In addition, raw material hoppers 11 and 12 for separately charging raw materials, and water injection nozzles 17 and 18 for adding water to the raw materials 13 and 14 charged respectively are attached. 10 is a support roller for supporting the outer cylinder 2 and 4 is a roller for supporting the outer cylinder 2 and
This is a drive gear for rotating. Raw material hoppers 11 and 12
Raw material charged into the inner cylinder 9 and the outer cylinder 2 from
13 and 14 are added by water injection nozzles 17 and 18, respectively, and are sent to the other end sides of the inner cylinder 9 and the outer cylinder 2 while rolling with the rotation of the cylinder, respectively. 2 is supported with the discharge ends 15 and 16 side slightly inclined downward. FIG. 1B is a cross-sectional view taken along the line AA of FIG. 1A, and shows the rolling state of the raw materials 13 and 14 in the inner cylinder 9 and the outer cylinder 2.

Using the mixer constructed as described above,
When the outer cylinder 2 is rotated by the drive motor 7 via the drive gear 4, the inner cylinder 9 is also rotated, and the raw materials 13 and 14 charged from the raw material hoppers 11 and 12 roll as shown in the figure. While the inner cylinder 9 and the outer cylinder 2 respectively
Through which water is mixed and granulated.
And discharged separately from 16.

Therefore, if two kinds of powder raw materials having different properties are charged from the raw material hoppers 11 and 12, the raw materials can be granulated separately and simultaneously.

The method of using a high CaO component raw material and a low CaO component raw material as the two kinds of powder raw materials is the above-mentioned invention, and the high CaO component raw material is placed in the inner cylinder 9 of FIG.
On the other hand, a method of charging a raw material of a low CaO component into the outer cylinder 2 is the above invention.

In the mixer having the double pipe structure, the outer cylinder 2 and the inner cylinder 9 rotate synchronously, so that the raw material charged in the inner cylinder 9 has a short rolling distance,
The rolling distance of the raw material charged therein becomes longer. That is, the granulation performance differs between the outer cylinder 2 and the inner cylinder 9, and the outer cylinder 2 has a characteristic that it is higher. On the other hand, the granulation property of the raw material is good for the raw material having a high CaO component and relatively poor for the raw material having a low CaO component as compared with the raw material having a high CaO component. If the raw material of the CaO component is supplied and the raw material of the low CaO component is supplied into the outer cylinder 2 having a high granulation performance, any of the raw materials can be brought into a favorable granulated state.

At the time of granulation, there is a concern that the raw material 14 in the outer cylinder 2 may come into contact with the inner cylinder 9, but as described above, the space factor of the raw material during rolling granulation of the cylindrical drum mixer is 10%. Small in size and hardly affected.

The above description is an example in which a drum-type mixer having a double-pipe structure is used. However, the method of the present invention is not limited to this, and a mixer having a triple or more multi-pipe cylindrical structure is used. Separate multi-split raw materials, and
It is also possible to carry out a granulation treatment at the same time. In addition, as described above, a multi-cylindrical tube structure is used to utilize the unused space in the central portion of the mixer to perform granulation with the conventional outer cylinder and simultaneously perform granulation with the inner cylinder. And increase the granulation efficiency.

The above-mentioned invention is an apparatus capable of carrying out the inventions of (1) to (4), and includes a drum type mixer having a double pipe structure shown in FIG. 1 as an example. However, the present invention is not limited to the double tube structure, and may have a triple or multiple tube structure.

The invention of the present invention is a drum type mixer having a cylindrical tube in which the latter half of the cylindrical tube in the raw material discharge side is a single tube.

FIG. 2 is a longitudinal sectional view showing the structure of an example of the mixing granulating apparatus according to the present invention. This apparatus is different from the apparatus of the invention shown in FIG. 1 in that the raw material discharge side of the cylindrical tube is not a double cylindrical tube but is constituted only by the outer cylinder 2. In the inner cylinder 9, granulation is mainly performed, and in a portion composed of only the outer cylinder 2, the granulated material granulated in the inner cylinder 9 and the outer cylinder 2 is mainly mixed. The length of the inner cylinder 9 is preferably about 7/10 of the length of the outer cylinder 2, and if shorter than this, granulation in the inner cylinder 9 will be insufficient, and if longer than this, mixing will be insufficient.

When this apparatus is used, different kinds of raw materials can be simultaneously granulated by one mixer and the granulated material can be mixed. That is, when different types of raw materials are charged into the outer cylinder 2 and the inner cylinder 9 and granulation is performed, granulation proceeds in each cylinder.
The granulated material (raw material 21) is discharged from the discharge end 15 of the inner cylinder 9 and moves to the outer cylinder 2, and the granulated material (raw material 22) of the outer cylinder 2
Mixed while moving to the discharge end 16 while rolling with
At the discharge end 16, the mixed raw material 24 is discharged.

This apparatus is not limited to a mixed granulation apparatus having a double cylindrical tube, but may have a triple or more multi-cylinder structure.

The above-mentioned drum type mixer of the present invention also has an advantage that it can be manufactured by relatively simple modification of a conventional existing mixer.

[0030]

EXAMPLES Using the raw materials (blended raw materials) shown in Table 1, granulation was carried out with three types of drum-type mixers shown in Table 2, and the obtained granulated product was 300 mm in diameter and 5 mm in height.
A sintering experiment was performed with a 00 mm pan device.

The raw materials of the C compound among the used compound raw materials are
It is a normal sintering raw material. The raw materials for A and B are
As shown in Table 1, the raw material of the C blend is a raw material (blended raw material) which is divided and blended for each of its constituent materials (iron ore, limestone, sinter and coke), and the raw material of the A blend is high CaO The raw material of the component and the raw material of the B mixture are raw materials of the low CaO component.

The operating conditions of the drum type mixer were such that the inclination angle of the drum was 5 °, the rotation speed was 6 rpm, and the feed rate of the raw materials to the drum was constant at a total of 800 T / h. The raw material used for baking the pot was a fixed amount of 70 kg.

Table 3 shows the results of the sintering experiment. Cases 1 and 2 are cases in which a raw material having a C composition is used. Case 1 is a case where granulation is carried out by a conventional drum mixer having a single tube structure. Case 2 uses a drum mixer having a double tube structure of the present invention. In this case, the raw materials were dispersed and granulated at an inner side ratio of 3: 7. When the granulating apparatus of the present invention was used, the granulating performance was improved as compared with the case using the conventional granulating apparatus, and an improvement in productivity was observed in a pot firing experiment.

Cases 3 to 6 show a case in which a raw material having a high CaO content of A and a raw material having a low CaO content of B are used in combination. In case 3, two types of materials having different CaO contents (A In this case, the raw materials (Blending and B blending) are separately granulated by using a conventional drum mixer of type 1 and then two kinds of granulated raw materials are mixed by hand and baked in a pot. On the other hand, in cases 4 and 5, the raw materials of the above two types of blending were separately separated by an inner cylinder and an outer cylinder using a double-pipe-type drum mixer of the present invention (invention) of type 2 (see FIG. 1). In the case where two kinds of granulated materials are mixed by hand and baked in a pot, case 4 is a case where a raw material of a high CaO component is charged into the outer cylinder, and case 5 is a case where a low CaO component is This is the case where raw materials are charged. Case 6 is a case where the mixture of the above two kinds of raw materials was granulated and mixed by the drum type mixer of the present invention (invention of the present invention (see FIG. 2)), and was then subjected to pot firing.

In the case 5 and the case 6 using the apparatus of the present invention, excellent results were obtained in both the productivity of the sinter and the reduction powdering resistance as compared with the case 3 using the conventional apparatus. Case 4 is similar to Case 3 (conventional example) in terms of sinter productivity and reduction powdering resistance,
There is a great advantage that granulation of the raw material of the blend and the raw material of the B blend can be performed simultaneously by one mixer without installing a new mixer.

[0036]

[Table 1]

[0037]

[Table 2]

[0038]

[Table 3]

[0039]

According to the present invention, when mixing and granulating powder raw materials such as fine ore by a drum type mixer, it is possible to granulate many kinds of raw materials simultaneously with one mixer. Further, mixing of granules is also possible. At the same time, the space utilization of the drum can be improved, and the granulation efficiency can be improved. Simultaneous granulation of such various kinds of raw materials can be easily performed by using the apparatus of the present invention.

[Brief description of the drawings]

FIG. 1 is a view showing a configuration of an example of a mixing granulation apparatus of the present invention, wherein (a) is a longitudinal sectional view, and (b) is a sectional view taken along the line AA of (a).

FIG. 2 is a longitudinal sectional view showing the configuration of another example of the mixing granulation apparatus of the present invention.

FIG. 3 is a view showing a configuration of an example of a conventional drum mixer, where (a) is a longitudinal sectional view, and (b) is a sectional view taken along line BB of (a).

Claims (5)

(57) [Claims] 1. A multi-cylinder pipe comprising a plurality of cylindrical pipes connected to each other so as to form concentric circles around a central axis of the cylindrical pipe in a state where the pipe is inclined with respect to a horizontal level in a moving direction of the raw material. Rotating, loading various kinds of powder raw materials having different properties from one end of the multi-cylindrical tube into each of the sections divided by each cylinder of the multi-cylindrical tube, and moving to the other end while rolling. A method for mixing and granulating raw materials. 2. The method according to claim 1, wherein the difference in the properties of the powder raw material is the concentration of the CaO component. 3. The multi-cylindrical pipe is a double-cylindrical pipe, and the difference in the properties of the powder raw material is the concentration of the CaO component, and the high-CaO component raw material is placed in a cylinder inside the double-cylindrical pipe. The method for mixing and granulating raw materials according to claim 1, wherein the raw material of the CaO component is charged between the inner cylinder and the outer cylinder of the double cylindrical tube. 4. A cylindrical pipe having a downward inclination in the moving direction of the raw material with respect to the horizontal level and rotatably supported, a raw material hopper for charging the raw material into an end of the cylindrical pipe,
An apparatus for mixing and granulating a raw material having a water injection nozzle for adding water to a charged raw material, wherein the cylindrical pipe comprises a plurality of cylindrical pipes connected to each other such that their cross-sectional shapes are concentric. An apparatus for mixing and granulating raw materials, wherein the raw material hopper and the water injection nozzle are provided in each section divided by each cylinder of the multi-cylindrical pipe. 5. A cylindrical pipe having a downward inclination in the moving direction of the raw material with respect to the horizontal level and rotatably supported, a raw material hopper for charging the raw material into an end of the cylindrical pipe,
A raw material mixing and granulating apparatus having a water injection nozzle for adding water to a charged raw material, wherein the first half of the raw material charging side of the cylindrical tube is connected to each other so that its cross-sectional shape is concentric. A raw material hopper and a water injection nozzle are provided for each section divided by each cylinder of the multi-cylindrical pipe, and the latter half of the raw material discharge side of the multi-cylindrical pipe is the multi-cylindrical pipe. A mixing and granulating apparatus for raw materials, wherein the mixing and granulating apparatus comprises only a pipe having a maximum diameter.