JPH05239561A - Manufacture of sintered ore - Google Patents

Abstract

PURPOSE:To improve the productivity of sintered ore even if pulverized ore is blended by beforehand granulating the pulverized ore together with a part of sintering main and auxiliary raw materials and directly carrying into a surge hopper without mixing with mixed granular materials of the remained sintering raw materials. CONSTITUTION:The pulverized ore 2 containing >=70wt.% of <=0.125mm particles together with a part 3 of the main and auxiliary raw materials and powdered coke 5 in the sintering raw materials stored in hoppers are discharged into a granulating machine 1 and binder 4 and water 6 are added beforehand to execute the granulation. On the other hand, the remained sintering raw materials 9 and the powdered coke 5 are mixed and granulated by a mixer 8, etc. Successively, the former pre-granulated material 7 and the latter mixed and granulated material 10 are continuously charged to a belt conveyor 13 without executing mutually mixing treatment, and are separately and directly carried into a surge hopper 12 of sintering machine 11. By this method, at the time of manufacturing the sintered ore by sintering the iron ore, a large quantity of the pulverized ore as a sintering raw material can be blended and also, the productivity of the sintered ore can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for improving the productivity of sinter while using fine ore as a raw material for sintering when sintering iron ore to produce sinter.

[0002]

2. Description of the Related Art The proportion of fine iron ore used as a sintering raw material tends to increase, but 70% by weight of particles of 0.125 mm or less
When the fine ore contained above is used as a part of the sintering raw material, it is mixed with other main and auxiliary raw materials for sintering and granulated and supplied to the sintering machine. It is known that the air permeability in the sintering process is impaired and the productivity of sinter is deteriorated.

As a method for improving this problem, Japanese Patent Publication No. 2-
In 37410 and JP-A-61-213328, granulation is performed in advance so that fine ore is attached to the surroundings of return or limonite as a nucleus, and this pre-granulated product is used as a main or secondary sintering additive. We propose a method of mixing and granulating with the raw materials.

Further, Japanese Patent Application Laid-Open No. 63-186832 proposes that a granulated product of fine ore and return ore be charged as a substitute for bedding ore into a sintering machine.

[0005]

[Problems to be Solved by the Invention] The former method in which fine ore is adhered to the surroundings of return ore and limonite to be pre-granulated, and the pre-granulated product is mixed and granulated with other main and auxiliary raw materials for sintering. In the case of mixed granulation of the pre-granulated product and other main and auxiliary raw materials for sintering, part of the pre-granulated product collapsed and became fine powder form again as other main and auxiliary raw materials for sintering. There is a problem of mixing. In other words, this collapsed part behaves in the same way as when the pre-granulation process is not performed, and if this collapse occurs, the productivity of the sintered ore will not be sufficiently improved despite the preliminary granulation. The problem came with it.

Further, this pre-granulated product is more likely to collapse as the amount of the fine ore compounded increases, so that it is difficult to produce a sinter by mixing a large amount of the finely divided ore by this method.

On the other hand, in the latter method of using a granulated product of fine ore and return ore as a bedding ore, this granulated product is not mixed and granulated with other main auxiliary raw materials for sintering. Although the problem of disintegration does not occur, the granulated product cannot be filled in a large amount in the sintering machine because it is limited in the amount of bedding ore used. Therefore, even with this method, a large amount of fine ore cannot be mixed to produce a sintered ore.

An object of the present invention is to solve the above problems and to provide a method for improving the productivity of sinter even if a large amount of fine ore is added.

[0009]

[Means for solving the problem] 70 particles of 0.125 mm or less
In a method for producing a sintered ore in which fine ore contained in an amount of not less than wt% is mixed into a sintering raw material together with other sintering main raw materials, sintering auxiliary raw materials, and carbonaceous materials, the present invention provides Pre-granulation together with a part of the raw materials, separately mixing and granulating the remaining sintering raw materials, and the former pre-granulated product and the latter mixed-granulated product respectively without undergoing a process of mixing with each other. The feature is that it is directly loaded into the surge hopper of the sintering machine.

[0010]

In the present invention, finely divided ore means iron ore containing particles of 0.125 mm or less in an amount of 70% by weight or more. Sintering main raw material refers to iron ore other than the fine ore, such as limonite, hematite, magnetite, and return ore at the time of sintering, which do not contain 70% by weight or more of particles of 0.125 mm or less, that is, fine powder. It has a larger particle size and particle size distribution than ore (coarse particles). Sintering auxiliary materials refer to slag components, binders, etc.
Specifically, it is serpentine, dolomite, limestone, quicklime, etc., which are often coarse particles, but fine particles can also be used. The carbonaceous material usually refers to powder coke, but coal, for example, anthracite powder, or a char obtained by pyrolyzing coal can also be used.

FIG. 1 illustrates a preferred embodiment of the method of the present invention. The method of the present invention will be described with reference to FIG.

First, the pre-granulation of fine ore is performed by the granulator 1. The granulator 1 is preferably a pelletizer capable of obtaining granules having a narrow particle size distribution,
It can also be performed with a mixer. A predetermined amount of fine ore 2 and sintering main and auxiliary raw material 3 stored in the hopper are cut out into a granulator 1 and charged into a granulator 1, and an appropriate amount of water 6 is added to the granulator to perform a granulation process, and a preliminary granulation is performed. Granules 7 are obtained.

At that time, the binder 4 (for example, quick lime or slaked lime powder) and the coke powder 5 can be mixed in appropriate amounts, and it is particularly preferable to mix the coke powder.
As described above, coal powder or char can be used instead of powder coke. Although the main sintering auxiliary material 3 is illustrated as being stored in one hopper in FIG. 1, it may be stored in separate hoppers. Sintering main auxiliary material 3
Sinter feed for return or limonite, hematite, magnetite,
Or coarse-grained limestone, dolomite, serpentine, etc.,
At least one of these may be used for pre-granulation, and not all types may be used.

On the other hand, the remaining sintering raw materials are mixed and granulated by the mixer 8 in another system. That is, the main auxiliary raw material 9 for sintering stored in the hopper is cut out together with the powdered coke 5 in a predetermined amount and mixed and granulated by the mixer 8 to obtain a mixed granulated product 10.

In this manner, the pre-granulated product 7 is obtained from the granulator 1 and the mixed granulated product 10 is obtained from the mixer 8 in different systems, and these are also obtained in the mixer 8 and the secondary mixer etc. However, they are directly loaded into the sintering machine 11 without being mixed or granulated with each other. That is, both are directly loaded into the raw material loading surge hopper 12 of the sintering machine 11. Actually, the pre-granulated material 7 and the mixed granulated material 10 are continuously put into the surge hopper 12 in an appropriate amount on the belt conveyor 13 which carries the raw materials into the surge hopper 12, so that they are merged into the surge hopper 12. Is brought in.

Therefore, in the surge hopper 12,
The pre-granulated product 7 will be mixed with the mixed granulated product 10 while maintaining the granulated form obtained by the granulator 1 as it is,
The table (pallet) of the sintering machine 11 in this mixed state
Loaded on top. Then, the surface is ignited by the igniter 14, and the sintering proceeds by downward ventilation.

According to the method of the present invention, since the pre-granulated product charged into the sintering machine maintains the particle morphology during the pre-granulation as it is, the air permeability at the time of sintering becomes good. Therefore, the productivity of the sintered ore can be improved. The details will be shown in an example described later, but from the surge hopper 12 to the sintering machine 11
The granulated product was sampled from the flow of the raw material charged into the reactor, and the harmonic mean particle size was calculated. As a result, a sufficient value was maintained, and the particle morphology when granulated by the granulator 1 was determined. It was confirmed that it was maintained as it was. It was also confirmed that the higher the proportion of fine ore in the total raw material, the higher the harmonic mean particle size and the better the air permeability. Here, the harmonic mean particle diameter (dp) is calculated by dp = 100 / Σ (x _i / d _i ) from the representative diameter (x _i ) of a certain particle size range and its ratio (d _i ).

[0018]

[Examples] Pre-granulated products were produced using a pelletizer under the compounding ratios shown in Table 1 (Examples 1 to 6). The fine ore used is hematite containing 90% by weight of particles of 0.125 mm or less. The water content supplied to the pelletizer was adjusted to a sufficient amount necessary for granulation in each case. On the other hand, the remaining main sintering and auxiliary materials were mixed and granulated with a coke powder in a mixing ratio shown in Table 1 by a mixer. At that time, they were mixed and granulated in two stages, a primary mixer and a secondary mixer. In Table 1, the total of the pre-granulated compound and the mixed granulated compound is the total sintering raw material (1
00%).

The pre-granulated product and the mixed granulated product of each example were directly charged into a surge hopper of a sintering machine as shown in FIG. 1 and sintered by the same sintering machine. At that time, sampling was performed from the raw material flow charged into the sintering machine from the surge hopper, and the harmonic mean particle size of the pre-granulated product therein was determined. In addition, in each example, the productivity of sinter (the daily production of sinter per unit sintered area) was determined. These results are also shown in Table 1.

For comparison, an example in which the same fine ore is not granulated before being compounded at the time of granulation in a mixer (Comparative Example 1) and an example in which a pre-granulated product is added at the time of granulation in a mixer The composition of (Comparative Example 2) is also shown in Table 1. These were also sintered under the same conditions. The harmonic mean particle size and productivity at that time are also shown in Table 1.

[0021]

[Table 1]

As can be seen from the results shown in Table 1, in Examples 1 to 6 according to the method of the present invention, compared with Comparative Examples 1 and 2, the harmonic mean particle size was large and the productivity of sinter was improved. I understand that

Curve A in FIG. 2 is a plot of the relationship between the blending ratio of the fine ore blended in Examples 1 to 6 and the harmonic mean particle size. From this, it is understood that the harmonic mean particle size is improved by adding a large amount of fine ore. As a result, the productivity is improved when a large amount of fine ore is used.

Curve B in FIG. 2 shows the relationship between the blending ratio of fine ore and the harmonic mean particle size when fine ore is blended during the mixing and granulation in the mixer according to Comparative Example 1.
4 shows the relationship between the blending ratio of fine ore and the harmonic mean particle diameter when the pre-granulated product was blended at the time of mixed granulation with a mixer, following Comparative Example 2.

As is clear from the results of FIG. 2, in the curves B and C of the comparative example, the harmonic mean particle size becomes smaller as the blending ratio of the fine ore becomes higher, whereas in the curve A of the example of the present invention, the fine powder becomes finer. The higher the blending ratio of ore, the larger the harmonic mean particle size. And, the value of the harmonic mean particle diameter is large in the present invention example. Therefore, by applying the method of the present invention, it is possible to use a large amount of fine ore and improve the productivity regardless of the blending ratio of the fine ore.

[0026]

As described above, according to the present invention, the productivity of sinter can be improved even if the amount of fine ore used is increased.

[Brief description of drawings]

FIG. 1 is a processing system diagram for explaining a method of the present invention.

FIG. 2 is a diagram showing the relationship between the blending ratio of the finely divided ores obtained in the examples of the present text and the harmonic mean particle size in comparison with the comparative examples.

[Explanation of symbols]

 1 Granulator 2 Fine ore 7 Pre-granulated material 8 Mixer 10 Mixed granulated material 11 Sintering machine 12 Surge hopper 13 Belt conveyor

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshiaki Nishimoto 11-1 Showa-cho, Kure-shi, Hiroshima Inside Steel Research Laboratory, Nisshin Steel Co., Ltd. (72) Inventor Nobuichi Aritomi 11-1 Showa-cho, Kure-shi, Hiroshima Nisshin Steel Co., Ltd.

Claims (3)

[Claims] 1. A method for producing a sintered ore, wherein fine ore containing particles of 0.125 mm or less in an amount of 70% by weight or more is compounded in a sintering raw material together with other sintering main raw materials, sintering auxiliary raw materials and carbonaceous materials, The fine ore is pre-granulated together with a part of the sintering main and auxiliary raw materials, and the remaining sintering raw materials are separately mixed and granulated, and the former pre-granulated product and the latter mixed granulated product are mixed with each other. A method for producing a sintered ore, characterized in that each is directly carried into a surge hopper of a sintering machine without undergoing a treatment. 2. The method for producing a sintered ore according to claim 1, wherein a binder is blended with the pre-granulated product. 3. The method for producing a sintered ore according to claim 1, wherein the pre-granulated product and the mixed granulated product are continuously charged on a belt conveyor leading to a surge hopper.