KR101377278B1 - Method of crushing iron ore material - Google Patents

Abstract

An object of this invention is to provide the grinding | pulverization method of an iron ore raw material which can increase the fine amount of an iron ore raw material. As a grinding | pulverization method of the iron ore raw material using a roll grinder, the 2nd iron ore raw material whose hardness is higher than this 1st iron ore raw material is mixed with the 1st iron ore raw material which is grind | pulverized. The first iron ore raw material and the second iron ore raw material thus mixed are put into the roll mill to provide a grinding method of iron ore raw material.

Description

Crushing method of iron ore raw material {METHOD OF CRUSHING IRON ORE MATERIAL}

The present invention relates to a grinding method of iron ore raw material, and more particularly to a grinding method for increasing the fine amount of iron ore raw material.

In recent years, the iron ore raw material used in a sintering machine has more fine powder than the iron ore raw material conventionally used. Therefore, when the iron ore raw material currently used is thrown into a sintering machine without performing pre-treatment, it is difficult to produce high quality sintered ore efficiently with low production efficiency by impairing the air permeability of a sintering machine. For this reason, the granulated material is put into a sintering machine after granulating the iron ore raw material with many fine powders.

However, since such granulated materials may be collapsed in the conveying process up to the sintering machine or in the sintering machine if the strength is weak, it is necessary to increase the strength of the granulated materials by assembling iron ore raw materials having a particle size distribution suitable for granulation. However, in order to obtain a particle size distribution suitable for such granulation, there is a shortage of fine powders of iron ore raw materials, in particular fine powders for improving granulation properties, for example, several tens of micrometers or less, in particular several micrometers or less.

Conventionally, in order to produce fine powder of an iron ore raw material, the method of crushing iron ore raw material using a roll grinder was employ | adopted. For example, Patent Documents 1 and 2 disclose techniques for grinding fine iron ore raw materials with a roll mill to produce fine powder having a particle diameter of 45 µm or less suitable for granulation. In addition, Patent Documents 3 and 4 disclose a technique of pulverizing an iron ore raw material supplied to a granulation apparatus with a roll mill to produce fine powder having a particle diameter of less than 22 µm suitable for granulation.

As disclosed in the Patent Documents 1 to 4 above, any of the conventional methods for crushing iron ore raw materials, for example, iron ore raw materials that are easy to be crushed, such as maramanba ore or deceased blockman ore, are rolls. It was crushed by a grinder. However, for example, iron ore raw materials that are difficult to be pulverized, such as pellet feed, are difficult to be pulverized because of their small particle diameter and high hardness, and are less likely to be pulverized. (Iii) mixed with the ground iron ore raw material.

Patent Document 1 Japanese Unexamined Patent Publication No. 2007-162127 Patent Document 2 Japanese Unexamined Patent Publication No. 2007-138244 Patent Document 3 Japanese Unexamined Patent Publication No. 2005-350770 Patent Document 4 Japanese Unexamined Patent Publication No. 2008-240159

By the way, in order to improve the intensity | strength of the said granulated material, it is calculated | required to further increase the fine amount of the iron ore raw material after grinding | pulverization. In order to further increase the fine amount of the iron ore raw material, it is conceivable to increase the crushing performance of the roll mill by excessively increasing equipment, for example, by increasing the roll press force. However, in order to make the grinding | pulverization performance of a roll grinder excessively strong, problems, such as a cost increase of a roll grinder, arise. Therefore, there is a demand for a method of increasing the fine amount of iron ore raw materials without increasing the facilities such as excessively increasing the grinding performance of the roll mill and increasing the roll press force.

Accordingly, the present invention has been made in view of the above problems, and an object of the present invention is to provide a novel and improved method for crushing iron ore raw materials, which is capable of increasing the fine amount of iron ore raw materials without reinforcing equipment of a roll mill. It is in doing it.

The inventors of the present invention and the like have made intensive studies, and the iron ore raw materials, which have high hardness and are difficult to be crushed, are mixed as a grinding aid, and the mixed iron ore raw materials are pulverized by a roll grinder to obtain iron ore raw materials obtained by grinding. It has been found that it can increase the differential amount of.

Accordingly, one aspect of the present invention is a method of crushing iron ore raw materials using a roll mill, in which a first iron ore raw material composed of at least one of maramanba ore, fisorite, deceased blockman ore, serpentine, and pilbara blend to be crushed. And the second iron ore raw material made of at least one of lyodoce pellet feed, MBR, MBR-PF, and lyodoce having a higher hardness than the first iron ore raw material, is mixed as a grinding aid having a mixing ratio of 10 to 45 mass%, and the mixed The first iron ore raw material and the second iron ore raw material are put into the roll mill, and pulverized.

Thereby, the 2nd iron ore raw material whose hardness is higher than a 1st iron ore raw material encourages the grinding | pulverization of the 1st iron ore raw material to which it grinds. Therefore, the fine amount of the iron ore raw material obtainable by the pulverization is increased, and the particle size distribution suitable for granulation can be obtained.

In addition, the grinding | pulverization characteristic of the said 1st and 2nd iron ore raw material is a grinding | pulverization ratio at the time of grind | pulverizing the said 1st iron ore raw material independently when the said 2nd iron ore raw material was grind | pulverized independently using the said roll grinder. Smaller than As a result, it is difficult for the second iron ore raw material itself to be crushed by a roll mill, and by promoting the pulverization of the first iron ore raw material to be crushed, it is possible to further increase the fine amount of iron ore and obtain a particle size distribution suitable for algae. It becomes possible. In addition, the said grinding | pulverization ratio is an index of how small the iron ore raw material after grinding compared with the grinding | pulverization, and it is an index of the difference of the "average particle diameter before grinding" and "average particle diameter after grinding" with respect to "average particle diameter before grinding". It is defined as a ratio.

The average particle diameter before grinding of the second iron ore raw material may be smaller than the average particle diameter before grinding of the first iron ore raw material. Thereby, since a 2nd iron ore raw material enters the clearance gap between 1st iron ore raw materials, the porosity of the mixed iron ore raw material falls. Therefore, the second iron ore raw material further encourages crushing of the first iron ore raw material, thereby further increasing the fine amount of iron ore. In addition, the average particle diameter here is the mass average particle diameter measured by the liquid-bed sedimentation method (the measuring method by an Andreagen pipette).

In addition, the mixing ratio of the second iron ore raw material is preferably 10 to 45% by mass. Thereby, the function as a grinding aid of a 2nd iron ore raw material can be improved. In addition, a mixing ratio is an index of which iron ore raw material occupies what ratio among all iron ore raw materials, and is represented by the ratio of the mass of all iron ore raw materials to the mass of which iron ore raw materials.

In addition, the second iron ore raw material is preferably a pellet feed. In addition, the pellet feed is preferably a lyodoce pellet feed.

As described above, according to the present invention, it is possible to increase the fine amount of the iron ore raw material without improving the grinding performance of the roll mill.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram which shows the whole structure of the sintering apparatus provided with the roll grinder used by the grinding method of the iron ore raw material which concerns on 1st Embodiment of this invention.
2 is a graph showing the relationship between the fine fraction of iron ore raw materials and the strength of granulated materials.
It is a schematic diagram which shows the roll grinder used by the grinding | pulverization method of the iron ore raw material which concerns on the 1st Embodiment of this invention.
4 is a schematic diagram showing a state in which only the first iron ore raw material is ground in the grinding method of the iron ore raw material according to the first embodiment of the present invention.
5 is a schematic diagram showing a state in which a mixture of a first iron ore raw material and a second iron ore raw material is crushed in the iron ore raw material grinding method according to the first embodiment of the present invention.
It is a graph which shows the particle size distribution before and after grinding | pulverization of the West Angelus single used for the grinding | pulverization method of the iron ore raw material which concerns on the Example of this invention.
Fig. 7 is a graph showing particle size distribution before and after crushing of yarn alone used in the grinding method of iron ore raw materials according to the same embodiment.
8 is a graph showing particle size distribution before and after crushing serpentine rock alone used in the iron ore raw material grinding method according to the same embodiment.
Fig. 9 is a graph showing particle size distribution before and after grinding of a lyodoce pellet feed alone used in a method for grinding an iron ore raw material according to the same embodiment.
10 is a graph showing the amount of fine powder after pulverization by the crushing method of iron ore raw materials according to the same example.
11 is a graph showing the amount of fine powder after pulverization by the crushing method of iron ore raw materials according to the same example.

EMBODIMENT OF THE INVENTION Very preferred embodiment of this invention is described in detail, referring an accompanying drawing below. In addition, in this specification and drawing, about the component which has substantially the same functional structure, the same code | symbol is attached | subjected and duplication description is abbreviate | omitted.

[One. Overall Configuration of Sintering Equipment]

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram which shows the whole structure of the sintering apparatus provided with the roll grinder which concerns on this embodiment.

As shown in FIG. 1, the sintering equipment of the present embodiment mainly includes a pseudo assembly line 20, a pellet assembly line 30, and a sintering machine 40. The pellet granulation line 30 is a production line for manufacturing granulated material (hereinafter, referred to as sintered raw material pellets) in which iron ore raw materials mainly composed of fine powder are assembled. On the other hand, the pseudo assembly line 20 is a production line for assembling the iron ore raw material including fine powder and granulation, and manufacturing granulated material (hereinafter referred to as "pseudo granulated material") to which fine powder is attached to granules which become nuclear particles.

First, an iron ore raw material is demonstrated. The iron ore raw material is used as the sintering raw material for producing the sintering machine 40 and the sintered light. In this embodiment, in the pellet granulation line 30, an iron ore raw material consists of a 1st iron ore raw material which is easy to be crushed, and a 2nd iron ore raw material which is hard to be crushed. The second iron ore raw material has a higher hardness than the first iron ore raw material. In addition, the second iron ore raw material has a smaller particle diameter than the first iron ore raw material. The first iron ore raw material can be any type of raw iron ore that is easily crushed. For example, Maramanba ore (name: West Angelus), fisorite (name: Yandy), deceased blockman ore, serpentine, pilbara blend Etc., iron ore raw materials with many crystal waters are mentioned. The second iron ore raw material may be any kind of iron ore raw material that is difficult to be pulverized, and examples thereof include pellet feed such as lyodoce pellet feed, MBR, MBR-PF, and lyodoce.

Since the iron ore raw material containing a lot of such fine powders has poor granulation property and low granules, the granules collapse in the conveying process up to the sintering machine 40 or the sintering process in the sintering machine 40. . For this reason, when the iron ore raw material containing much fine powder is introduce | transduced into the sintering machine 40 as it is, a significant air permeability will deteriorate and the productivity of a sintered ore will be inhibited. Therefore, it is necessary to perform the granulation process mentioned later with respect to iron ore raw material, and to raise the intensity | strength of a granulated material.

Moreover, as a binder added to a kneader, from a viewpoint of improving granulation property, for example, dispersing agents, such as a polyacrylic acid type (to promote solid crosslinking, include an aqueous solution and a colloid added with a dispersing agent), quicklime, At least one kind of lignin can be used.

The iron ore raw materials as described above are classified according to their type and particle size, and then assembled (pseudo granulated or pelletized) in two lines of granulation lines, namely, pseudo granulation line 20 and pellet granulation line 30, to sinter raw material pellets. And pseudo-assemblies are prepared. Each assembly line is explained in full detail below.

First, the pseudo assembly line 20 will be described in detail. The pseudo assembly line 20 is a line for manufacturing a pseudo granulated product in which fine powder (for example, a particle diameter of 250 µm or less) is attached to granules (for example, particle diameter of 3 mm or more) of iron ore raw materials to be nuclear particles. . As shown in FIG. 1, the pseudo assembly line 20 is a kneading kneading the raw material tank 21 for storing the iron ore raw material including granulation and fine powder, the sieve separator 22, and the iron ore raw material for kneading the water ore raw material. Machine 23 and a granulator 24 for assembling a kneaded iron ore raw material to produce a pseudo granulated product.

The raw material tank 21 stores iron ore raw materials including granulated and fine powder (for example, physolite ore), iron ore raw materials including powdered coke, limestone, and the like. 22) is used for assembling over a predetermined particle diameter (e.g., 3 mm or more) and for fine powder below. Since granulation can be used as a nuclear particle as it is, it is conveyed to the granulator 24. On the other hand, the fine powder is fed into a kneading machine 23 made of, for example, a reggae mixer, and kneaded together with a binder to produce a kneaded product. The kneader 23 can use a blade rotary kneader, such as a proshare mixer and an Eirich mixer.

The kneaded material obtained by the kneader 23 and the granulation from the sieve separator 22 are fed into a granulator 24 made of a drum mixer or the like. For example, a drum mixer, a pan pelletizer, or the like can be used for the granulator 24. By this granulator 24, a kneaded material of iron ore raw material is granulated (pseudo-granulated) to become a pseudo granulated product. Specifically, by the granulation process by the granulator 24, the fine powder (for example, particle diameter 250 micrometers or less) contained in powder coke, other iron ores, and a binder adheres around the nucleus particle which is granulation, Pseudo granules (eg, particle diameters of 1 to 10 mm) are prepared.

Next, the pellet assembly line 30 is demonstrated in detail. The pellet assembly line 30 is a line which manufactures sintering raw material pellets which are granules which assembled the iron ore raw material which mainly makes the fine powder below a predetermined particle diameter. The sintered raw material pellets are granulated products having a particle diameter of 1 to 10 mm and an average particle diameter of 5 mm, for example.

As shown in FIG. 1, the pellet granulation line 30 includes a raw material tank 31 for storing the first iron ore raw material mainly composed of fine powder, a sieve separator 32 and a raw material for storing the second iron ore raw material. Assembling and sintering the tank 33, the first iron ore raw material and the second iron ore raw material, a kneader 34 for kneading the iron ore raw material and binder after grinding, and the kneaded iron ore raw material A granulator 35 and a sieve separator 36 for producing raw material pellets and a dryer 37 for drying the granulated sintered raw material pellets are provided.

In the raw material tank 31 of the pellet assembly line 30, a first iron ore raw material containing a lot of fine powder, for example, maramanba ore (name: West Angelus), deceased blockman ore, and the like are stored. As the first iron ore raw material, granules having a predetermined particle diameter or more are sorted and removed in advance by a sieve separator (not shown) or the like, and the fine powder (for example, a particle diameter of 3 mm or less) is made easier to assemble. And the viewpoint of the strength development of the granulated product.

The first iron ore raw material supplied from the raw material tank 31 is first sieved by a sieve separator 32, and fine powder having a predetermined particle diameter (for example, 3 mm) or less is supplied to the grinder 50. On the other hand, the particles having the predetermined particle diameter or more are supplied to the granulator 24 of the pseudo assembly line 20 for use as the nuclear particles of the above-mentioned pseudo granules.

On the other hand, all of the second iron ore raw materials supplied from the raw material tank 33 have been directly introduced into the kneader 34 in the past. However, in the second iron ore raw material of the present embodiment, fine powder such as lyodoce PF (average particle diameter 0.055 mm or less) is supplied to the grinder 50. The grinder 50 is comprised, for example with a roll grinder. The crusher 50 crushes the first iron ore raw material and the second iron ore raw material into a predetermined particle size distribution. In this way, the first iron ore raw material and the second iron ore raw material are pulverized and finely divided and grained, so that the subsequent granulation treatment can be made easier. This grinder 50 is a feature of this embodiment, and will be described later in detail.

Next, in the kneader 34, after the binder and the water are added to adjust the moisture, finely divided iron ore raw materials are kneaded. In this embodiment, as this kneader 34, a blade rotary kneader, such as a radig mixer and a proshare mixer, is used, for example. As described above, in the present embodiment, the kneading machine 34 is provided at the front end of the granulator 35 to increase the kneading ability of the iron ore raw material and the binder.

The sintered raw material after kneading by the kneader 34 is put into the granulator 35 and granulated. As the granulator 35, a drum mixer, a pan pelletizer, or the like can be used, for example. By granulation by such a granulator 35, for example, a sintered raw material which is a substantially spherical granule having a particle diameter of 1 to 10 mm, preferably a particle diameter of 3 to 6 mm (for example, an average particle diameter of 5 mm). Pellets are prepared. The particle size distribution of this sintered raw material pellet may be 70 mass%, for example, 3 mm or more of particle diameters.

The sintered raw material pellets thus produced are dried by a dryer 37 after the granulated substance having a predetermined particle diameter or more is sorted by the sieve separator 36.

As described above, the pseudo granulated material assembled in the pseudo assembly line 20 and the sintered raw material pellets assembled in the pellet assembly line 30 are blended at a predetermined compounding ratio and supplied to the sintering machine 40. The sintering machine 40 sinters the above two kinds of sintered raw material granulated bodies to produce a sintered ore. The sintered ore is supplied to the blast furnace after being crushed by a crusher (not shown) and cooled by a sinter cooler (not shown).

In the above, the whole structure of the sintering apparatus which concerns on this embodiment was demonstrated. In this embodiment, in the said pellet granulation line 30, in order to increase a fine amount, the mixture of the 1st iron ore raw material and the 2nd iron ore raw material is grind | pulverized with the grinder 50. As shown in FIG. And the fine powder obtained is thrown into the kneading machine 34, and it knead | mixes. This embodiment has the characteristics in the grinding | pulverization method of the iron ore raw material by this grinder 50. As shown in FIG. Conventionally, a second iron ore raw material such as pellet feed, which is directly added to the kneader 34, is mixed with the first iron ore raw material, and then the iron ore raw material is pulverized by the grinder 50. The grinding | pulverization method of the iron ore raw material of the roll grinder 50 which is the feature which concerns on this embodiment is mentioned later (refer FIG. 3 thru | or 5).

[2. Relationship between Microparts of Iron Ore Raw Materials and Granules]

Next, with reference to FIG. 2, it demonstrates in detail about what can obtain a high strength granulated material by increasing the fine amount of an iron ore raw material. 2 is a graph showing the relationship between the fine fraction of iron ore raw materials and the strength of granulated materials. At this time, the fine powder in FIG. 2 means an iron ore particle having a particle diameter of less than 10 μm. In addition, the particle diameter shown in FIG. 2 is based on the liquid-phase sedimentation method (measurement method by an Andreagen pipette), and is measured based on the sedimentation velocity in the liquid layer which changes with a particle diameter.

As shown in FIG. 2, it can be seen that any of the three types of iron ore (iron ore A, iron ore B, and iron ore C) mentioned above improves the strength of the granulated product as the amount of fines increases. In other words, in order to improve the strength of the granulated product, it is necessary to increase the fine amount of the iron ore raw material. Therefore, in the crushing method of the present embodiment, the first iron ore raw material is not ground alone, but the second iron ore raw material is mixed with the first iron ore raw material to be ground. Thereby, a 2nd iron ore raw material becomes a grinding aid, and encourages grinding | pulverization of a 1st iron ore raw material.

[3. Configuration of Roll Grinder]

Next, with reference to FIG. 3, the roll grinder 50 used by the iron ore raw material grinding method which concerns on 1st Embodiment is demonstrated. FIG. 3: is a schematic diagram which shows the roll grinder 50 used by the grinding method of the iron ore raw material which concerns on this embodiment.

As shown in FIG. 3, the roll grinder 50 is a compression mill of a biaxial roll type | mold. The roll mill 50 mainly includes a driven side roll 51, a fixed side roll 53, and a hopper 55.

Although the driven roll 51 and the fixed roll 53 can use a smooth surface as shown in the figure, you may use the thing which has an unevenness | corrugation on the surface. In addition, the driven side roll 51 and the fixed side roll 53 may be formed in the same magnitude | size, and may be formed so that one side may become larger than the other one. Moreover, each center axis | shaft (not shown) of the driven side roll 51 and the fixed side roll 53 is parallel, and it is good also parallel to the surface of installation places, such as a ground. That is, the driven side roll 51 and the fixed side roll 53 are preferably provided horizontally.

In addition, the driven side roll 51 and the fixed side roll 53 have the rotating shaft part 52 and the rotating shaft part 54, respectively. The rotary shaft portion 52 and the rotary shaft portion 54 are formed to penetrate the central axes of the driven roll 51 and the fixed roll 53, respectively.

Moreover, the hopper 55 is provided in the driven side roll 51 and the fixed side roll 53 with the clearance gap with the roll surface which the lower part rotates. Hopper 55 may have any size and shape as long as it is possible to inject iron ore raw material. The upper part of the hopper 55 has a substantially rectangular parallelepiped shape, for example as shown in FIG.

The driven side roll 51 is rotated by the rotation shaft portion 52. In addition, the fixed side roll 53 is also rotated by the rotation shaft portion 54. Rotating the rotating shaft part 52 and the rotating shaft part 54 is a drive apparatus (not shown) which consists of a motor, a speed reducer, etc., for example. Each drive device is provided in each roll, or a pair of motor drives both a driven side and a fixed side roll by the output shaft of 2 axes through a reducer. In addition, the roll reduction force (force F in the direction of the arrow in FIG. 3) can be applied to the driven side roll 51 by a hydraulic cylinder (not shown). The hopper 55 has a side wall, and prevents the iron ore raw material introduced from flowing from between rolls.

In the roll mill 50 having such a structure, iron ore raw materials are first introduced into the hopper 55. It is pulverized when passing between the driven side roll 51 and the fixed side roll 53 in order from the iron ore raw material accumulated in the lower part of the hopper 55. The pulverization is performed by applying a roll reduction force F to the driven side roll 51 in a state in which the driven side roll 51 and the fixed side roll 53 are rotated by the rotating shaft portion 52 and the rotating shaft portion 54, respectively. Is realized. Although it demonstrates in detail below, in this embodiment, after mixing a 1st iron ore raw material and a 2nd iron ore raw material, this mixed 1st iron ore raw material and 2nd iron ore raw material are thrown into the hopper 55. FIG. Since the first iron ore raw material is easy to be crushed and the second iron ore raw material is hard to be crushed due to its high hardness, the first iron ore raw material is mainly pulverized by a roll reduction force, and the second iron ore raw material promotes the grinding of the first iron ore raw material. It is mainly responsible for the function as a grinding aid.

[4. Grinding State of Iron Ore Raw Materials]

Next, the grinding | pulverization method of the iron ore raw material by the roll grinder 50 which has such a structure is demonstrated in detail, referring FIG. 4 and FIG. 4 is a schematic diagram showing a conventional grinding method of iron ore raw materials. The grinding | pulverization method of the iron ore raw material which concerns on this embodiment is implement | achieved by the roll grinder 50. As shown in FIG. A description with reference to FIGS. 4 and 5 is as follows.

As shown in FIG. 4, the 1st iron ore raw material is thrown into the hopper 55 of the roll grinder 50. As shown in FIG. As a result, the first iron ore raw material tries to pass between the driven side roll 51 and the fixed side roll 53. At that time, the first iron ore raw material is crushed to pass between the rolls while being compressed by the driven side roll 51.

Conventionally, only the first iron ore raw material which is easily crushed as the iron ore raw material crushed by the roll mill 50 has been used. For example, maraman ore (named West Angelus), fisorite (named Yandy), serpentine, and the like have been mixed and used. In addition, iron ore raw materials with a large number of crystals such as deceased blockman ores and pilbara blends are also used. The maramanba ore is an Australian iron ore of the Getite-Matite tissue subject. The deceased blockman ore is an Australian iron ore of the hematite-gettite tissue subject. On the other hand, iron ore raw materials having a small number of crystals such as lyodoce, MBR and pellet feed and having a dense structure have been mixed with the crushed iron ore raw materials in the step of kneading with a kneader without grinding. At this time, pellet feed is a collection of iron-rich particles by gravity sedimentation method after grinding ore. For example, lyodoce pellet feed (same as lyodoce PF in the drawing and table), MBR- PF etc. are mentioned. In addition, the MBR-PF is a brazilian iron ore raw material of the hematite tissue, relatively high hardness, the average particle diameter is less than 0.125 mm.

With respect to the grinding method by the conventional roll mill 50 as described above, in order to improve the strength of the granulated product, it is required to further increase the fine amount of the iron ore raw material after grinding. Until now, in order to further increase the fine amount of this iron ore raw material, the grinding performance of the roll grinder 50 had to be improved. More specifically, as the roll reduction force by the driven side roll 51 increases, the grinding of the iron ore raw material proceeds, but in order to increase the roll reduction force, a hydraulic cylinder (not shown) or the driven side roll 51 is used. Or it was necessary to improve the performance, such as the fixed side roll 53 and the structure (not shown) which supports them. That is, it was necessary to improve the performance of the roll grinder 50 at high cost.

Next, the grinding | pulverization method of the iron ore raw material which concerns on this embodiment is demonstrated, referring FIG. 5 is a schematic diagram showing a grinding method of an iron ore raw material according to the present embodiment.

As shown in FIG. 5, iron ore raw material is thrown into the hopper 55 of the roll grinder 50. As shown in FIG. In contrast to the example shown in FIG. 4, in the example shown in FIG. 5, after the first iron ore raw material West Angelus, Jandi and serpentine are mixed with the second iron ore raw material, the lyodoce pellet feed, the hopper of the roll grinder 50 55) This mixed iron ore raw material is charged. In other words, the first iron ore raw material which is easy to be crushed is mixed with the second iron ore raw material which is hard to be crushed, and then pulverized by the roll mill 50.

At this time, the hardness of the iron ore raw material is shown in Table 1.

With reference to Table 1, the hardness of an iron ore raw material is demonstrated taking West Angeles, Yandi, and Rio dose as an example. The said crushability is represented by the force of a mechanical characteristic, for example, it is difficult to grind | pulverize, so that hardness is high, and it is easy to grind | pulverize, while hardness is low. In addition, hardness is the hardness prescribed | regulated in JIS, for example, and is measured by the hardness test.

In addition, the crushability is expressed by other mechanical properties other than hardness, and is also evaluated by the average crush strength shown in Table 1. At this time, an average crush strength is a parameter of a mechanical characteristic, and the average crush strength shown in Table 1 is measured by the following measuring procedures of (1)-(3).

(1) After drying the iron ore raw material provided for the test, the particle size is set to 2 to 28 mm by a sieve.

(2) The crush strength of each iron ore raw material is measured by a compression test machine (PT-200N manufactured by Minebea, maximum compressive strength: 200 N, head drop rate 5 mm / min).

(3) About 90 iron crush strengths about each iron ore raw material, the average value (N / piece) is calculated | required.

The average crush strength measured in this measurement order is 61 N / piece of West Angelus, 54 N / piece of Jandi, and 80 N / piece of Lyodoce. That is, lyodoce having high average crush strength is hard to be crushed. West Angelus and Yandy, on the other hand, are relatively crushed. In addition, the ease of grinding is also evaluated by the grinding ratio. This grinding | pulverization ratio is defined as the reduction rate of the average particle diameter after grinding | pulverization with respect to the average particle diameter before grinding | pulverization, and can be calculated | required by following formula (1).

Grinding ratio = {(average particle diameter before grinding)-(average particle diameter after grinding)} × 100 / (average particle diameter before grinding) ... (Formula 1)

The said average particle diameter before grinding | pulverization points out the average particle diameter before grinding | pulverization of each iron ore raw material alone, and the average particle diameter after grinding | pulverization refers to the average particle diameter after grinding | pulverization of each iron ore raw material alone.

In addition, it demonstrates, referring FIG. In this way, since the second iron ore raw material, which is hard to be crushed at high hardness, such as lyodoce, is mixed with the first iron ore raw material which is easy to be crushed and crushed by the roll mill 50, the second iron ore raw material is the first iron ore raw material as the grinding aid. Encourages crushing. Therefore, the fine amount of an iron ore raw material can be increased.

In addition, in order for this second iron ore raw material to further function as a grinding aid, it is preferable to further increase the filling rate between the first iron ore raw materials of the roll mill 50. That is, the second iron ore raw material is preferably smaller in average particle diameter than the first iron ore raw material. As the average particle diameter is smaller, the filling ratio between the first iron ore raw materials of the roll mill 50 can be increased, and when the iron ore raw material passes between the rolls, the roll reduction force more easily acts on the first iron ore raw material. It is considered that the grinding of the first iron ore raw material is encouraged. In this way, not only from the viewpoint of the mechanical properties described above, but also from the viewpoint of physical properties such as the average particle diameter, a pellet feed having the same relatively small particle size as the lyodoce pellet feed may be used as the grinding aid.

As mentioned above, in this embodiment, the 2nd iron ore raw material which is high in hardness and is hard to be crushed is mixed with the 1st iron ore raw material which is easy to be crushed, and the mixed iron ore raw material is grind | pulverized by the roll grinder. Therefore, the grinding | pulverization of the 1st iron ore raw material which is high in hardness, and is easy to grind the 2nd iron ore raw material which is hard to be crushed is encouraged. In this way, it becomes possible to increase the fine amount of the iron ore raw material without improving the performance of the roll mill. As a result, productivity of a sintered ore can be improved by improving the intensity | strength of a granulated material and improving air permeability in a sintering process.

In addition, the above-mentioned iron ore raw material was named based on the name of the mine from which the iron ore raw material is collected. Therefore, even if the name of the iron ore raw material currently called lyodoce pellet feed is changed by the change of the name of a mine, for example, the iron ore raw material which is substantially the same as the lyodoce pellet feed in this embodiment is used. It is considered the same iron ore raw material.

<Examples>

Hereinafter, an embodiment of the present invention will be described.

In addition, the numerical value etc. which are used for the following examples are illustrations for easy understanding of this invention, and this invention is not limited to a following example.

[Pulverization Test of Each Iron Ore Raw Material]

First, the grinding test before and after grinding of each iron ore raw material alone is demonstrated.

In this test, the particle size distribution before and after crushing by the roll mill of each iron ore raw material alone was measured. By measuring the particle size distribution before and after crushing by the roll mill of each iron ore raw material, the ease of grinding of each iron ore raw material when the iron ore raw materials are mixed and ground by a roll mill can be specified.

The iron ore raw materials used in this test are West Angelus, Jandy, and Rio dose pellet feeds (hereinafter referred to as Rio dose PF shown in Fig. 1) and serpentine rock shown in Table 1 above. West Angeles, Jandy and Rio dose pellet feeds are as described above. In addition, serpentine is a sub raw material for adjusting the Mg0 component in a sintered ore.

This test is carried out by measuring the particle size distribution of each of the iron ore raw materials before milling and after milling alone.

The test conditions of this test are as follows. In addition, particle size distribution measurement by the following laser diffraction / scattering method is performed based on the amount of scattered light and the scattering direction of the light which are scattered when the laser is irradiated with visible light.

Roll Grinder 2-Axis Roll Rolling Mill

Roll size 250 mm diameter x 100 mm length

Roll rolling force 6 tons

Roll rotation speed 42rpm

Particle size distribution measurement Measurement by laser diffraction and scattering method

Next, with reference to FIGS. 6-9, the test result of this test is demonstrated. 6 is a graph showing particle size distribution before and after crushing of West Angelus alone. 7 is a graph showing the particle size distribution before and after crushing of Jandi alone. 8 is a graph showing particle size distribution before and after grinding serpentine rock alone. 9 is a graph showing particle size distribution before and after grinding of lyodoce pellet feed alone.

In addition, the definition of each term in FIGS. 6-9 is as follows.

Accumulated mass ratio: Mass ratio (mass%) with respect to the total iron ore raw material of the iron ore raw material which is below the particle diameter in any particle diameter.

Mass ratio before grinding: Mass ratio (mass%) of iron ore raw materials having respective particle diameters to iron ore raw materials before grinding by a roll mill

Mass ratio after grinding: Mass ratio (mass%) of iron ore raw materials having respective particle diameters relative to iron ore raw materials after grinding by a roll mill.

As shown in Fig. 6, when the west angelus alone was pulverized by a roll mill, the cumulative mass ratio after pulverization increased with respect to all particle diameters relative to the cumulative mass ratio before pulverization. In addition, as shown in FIG. 7, even when a yarn was grind | pulverized with a roll mill, the cumulative mass ratio after grinding | pulverization with respect to the cumulative mass ratio before grinding | pulverization increases with respect to all particle diameters. In addition, as shown in FIG. 8, even when serpentine rock was grind | pulverized by the roll grinder, the cumulative mass ratio after grinding | pulverization with respect to the cumulative mass ratio before grinding | pulverization increases in all particle diameters. However, as shown in Fig. 9, when the lyodoce pellet feed alone was pulverized with a roll mill, the cumulative mass ratio after grinding was slightly increased with respect to the cumulative mass ratio before grinding, but the degree of West Angelus, Jandy, and serpentine Did not increase.

Thus, Table 2 shows the pulverization ratio quantitatively showing the crushability of the lyodoce pellet feed, West Angelus, Yandi and serpentine by the roll mill.

In addition, the average particle diameter in Table 2 is the particle diameter (mm) which the said cumulative mass ratio becomes 50%. In addition, a grinding | pulverization ratio is a ratio represented by the said Formula (1).

As shown in Table 2, the grinding | pulverization rate of each iron ore raw material is 67% for West Angelus, 92% for Yandi, 59% for serpentine, and 18% for lyodoce pellet feed. Iron ore raw materials having a high grinding ratio are easily crushed by a roll mill. That is, West Angelus, Yandy and serpentine, which are the first iron ore raw materials, are relatively easy to be crushed by the roll mill, but the lyodoce pellet feed, which is the second iron ore raw material, is difficult to be crushed by the roll mill. Thus, as shown in Table 1, it is considered that one of the factors that lyodoceed pellet feed, which is the second iron ore raw material, is harder to crush than the first iron ore raw material, is that the lyodoceed pellet feed has a higher hardness than the first iron ore raw material. . In addition, it is considered that the lyodoceed pellet feed is harder to be pulverized than the first iron ore raw material, as shown in Table 2, that the lyodocet pellet feed is smaller in average particle diameter before pulverization than the first iron ore raw material.

[Pulverization Test of Mixed Iron Ore Raw Materials]

Next, the grinding test of the mixed iron ore raw material which concerns on this embodiment is demonstrated.

In this test, West Angelus, Jandi, and serpentine, which are the first iron ore raw materials, were mixed with the lyodoce pellet feed, which is the second iron ore raw material, and then pulverized by a roll mill, and the particle size distribution before and after grinding was measured (Example 1, 2). In addition, after crushing each iron ore raw material by a roll mill, the particle size distribution when the iron ore raw materials were mixed was calculated based on the measurement result of the particle size distribution in which each iron ore raw material was crushed alone (Comparative Example). By this test, it can demonstrate that the fine amount of iron ore raw material is increased by mixing iron ore raw materials which are hard and hard to be crushed, such as lyodoce pellet feed, and then pulverizing with a roll mill.

As shown in Table 3, in Example 1, the mixing ratio of the first iron ore raw material is 49% by mass, 22% by mass, and 6% by mass in the order of West Angelus, Yandy, and serpentine. In addition, the mixing rate of the lyodoce pellet feed which is a 2nd iron ore raw material is 23 mass%. On the other hand, in Example 2, the mixing ratio of the first iron ore raw material is 49% by mass, 0% by mass, and 6% by mass in the order of West Angelus, Yandy, and serpentine. In addition, the mixing rate of the lyodoce pellet feed which is a 2nd iron ore raw material is 45 mass%. Except that the iron ore raw materials were mixed at such a mixing rate and then ground by a roll mill, the test conditions were the same as those used in the grinding tests of the respective iron ore raw materials alone. In addition, the mixing ratio is represented by the following formula (2), and as in the present embodiment, all the mixed iron ore raw materials are not limited to the first iron ore raw materials and the second iron ore raw materials.

Mixing rate (%) = (mass of any mixed iron ore raw material) × 100 / (mass of all mixed iron ore raw material) ... (Formula 2)

First, with reference to FIG. 10, the measurement result of Example 1 and a comparative example is demonstrated. 10 is a graph showing the relationship between the mixing ratio of lyodocet pellet feed and the mass ratio of the fine amount after grinding. The graph shown in FIG. 10 is calculated based on the particle size distribution measurement mentioned above. At this time, in this embodiment, a powder having a particle diameter of less than 8 µm is used as the fine powder. In addition, the "pre-mixing and grinding | pulverization" shown in FIG. 10 means the iron ore raw material obtained by grind | pulverizing after mixing a 1st iron ore raw material and a 2nd iron ore raw material, and the plot of the graph shows the fine powder (particle diameter of 8 The result of the mass ratio of the iron ore raw material (less than micrometer). In addition, the "mixing after grinding" means the iron ore raw material which can be obtained by grind | pulverizing a 1st iron ore raw material and a 2nd iron ore raw material independently, and the graph shows the fine powder (particle diameter of 8 micrometers) of this iron ore raw material. The result of the mass ratio of less than iron ore raw material) is shown. In addition, "before grinding" means the iron ore raw material obtained by mixing the 1st iron ore raw material and the 2nd iron ore raw material before grinding | pulverization, The plot of the graph shows the mass of the fine powder (iron ore raw material whose particle diameter is less than 8 micrometers) of this iron ore raw material. The result of the ratio is shown.

In addition, with respect to the mixing ratio of the lyodoce pellet feed in the graph shown in FIG. 10, the mixing ratio of West Angelus, Jandy, and serpentine is constant at 49: 22: 6. That is, for example, in the case where the mixing ratio of lyodoce pellet feed is 10 mass%, the mixing ratio of West Angelus, Jandy and serpentine is 49: 22: 6, and the lyodoce pellet feed is 10 mass with respect to all iron ore raw materials. % Indicates mixing. Similarly, for example, 20% by mass indicates that the mixing ratio of West Angelus, Yandi, and serpentine is 49: 22: 6, and that the lyodocet pellet feed is mixed with 20% by mass of all iron ore raw materials.

As shown in FIG. 10, when the mixing ratio of the lyodoce pellet feed was 23 mass%, the fine amount after grinding was improved about 4.5 mass% in "pre-milling and milling" with respect to "mixing after milling". In addition, even when the mixing ratio of West Angelus, Jandy and serpentine is 49: 22: 6, and the mixing ratio of the lyodocet pellet feed is 10 mass%, the "mixing after premixing" is " The fine amount after grinding was improved by about 1% by mass. Similarly, even when the mixing rate of the lyodoce pellet feed was 15% by mass, the amount of fine powder after pulverization was improved by about 2.5% by mass in the "pre-pulverization after pulverization" to "mixing after pulverization".

Next, with reference to FIG. 11, the measurement result of Example 2 and a comparative example is demonstrated. FIG. 11 is a graph showing the relationship between the mixing ratio of the lyodoce pellet feed and the mass ratio of the fine amount after grinding, as in FIG. 10. About the graph shown in FIG. 11, it was created in the same manner as the graph shown in FIG. 10 except that the mixing ratio shown in Table 3 relates to Example 2. FIG.

In addition, even in the graph shown in FIG. 10 and the mixing ratio of any of the graphs shown in FIG. 10 with respect to the mixing ratio of the lyodoce pellet feed in the graph shown in FIG. That is, for example, when the mixing ratio of lyodoce pellet feed is 10 mass%, the mixing ratio of West Angelus and serpentine is 49: 6, and the lyodoce pellet feed is mixed by 10 mass% with respect to all iron ore raw materials. Indicates. Similarly, 20 mass% means that the mixing ratio of the West Angelus and the serpentine is 49: 6, which indicates that the lyodoce pellet feed is 20 mass% mixed with all the iron ore raw materials.

As shown in FIG. 11, when the mixing ratio of the lyodoce pellet feed was 45 mass%, the fine amount after pulverization improved about 8.5 mass% in "pre-milling and milling" with respect to "mixing after milling".

As mentioned above, also in the case of Example 1 and Example 2, it turns out that in the "pre-mixing grinding | pulverization" compared with "mixing after grinding | pulverization", the amount of fine powder after grinding | pulverization improves significantly. This result is thought to be due to the high hardness and the lyodoce pellet feed, the second iron ore raw material, which acts as a grinding aid to promote crushing of the first iron ore raw materials West Angelus, Yandi, and serpentine in a roll mill. It is also believed that this result is due to the fact that the lyodoce pellet feed, which is the second iron ore raw material, has a smaller particle diameter than West Angelus, Jandy, and serpentine, which is the first iron ore raw material, and improves the filling rate between the iron ore raw materials. In other words, when the lyodoce pellet feed is not between the rolls of the roll mill, the filling rate between the first iron ore raw materials is low, and the first iron ore raw materials easily pass between the rolls. However, when the lyodoce pellet feed is between the rolls of the roll mill, the filling rate between the first iron ore raw materials is increased to make it difficult for the iron ore raw materials to pass between the rolls. Therefore, it is thought that the pressure of a roll grinder becomes easy to act on iron ore raw material, and iron ore raw material becomes easy to grind. As a result, it is thought that the fine amount of iron ore raw material increases.

As mentioned above, although highly preferred embodiment of this invention was described in detail, referring an accompanying drawing, this invention is not limited to this example. If it is a person having ordinary knowledge in the field of the technology to which this invention belongs, it is clear that it can be conceived to various changes or modifications within the range of the technical idea described in the claim, and these are also naturally seen It is understood to belong to the technical scope of the invention.

For example, in the said embodiment, although the roll grinder used by the grinding | pulverization method of the iron ore raw material of this invention was set as the biaxial roll type compression mill, this invention is not limited to this example. For example, a backup roll may be provided. In addition, it is not limited to the example shown in FIG. 3, If an iron ore raw material can be grind | pulverized, it can change a design into arbitrary structures.

&Lt; Industrial applicability >

ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to increase the fine amount of iron ore raw material, without improving the grinding | pulverization performance of a roll grinder, and it is highly industrially applicable.

20 doctor assembly lines
21 Raw Material Tank
22 sieve selector
23 kneader
24 Assembly Machine
30 pellets assembly line
31 Raw Material Tank
32 sieve selector
33 Raw Material Tank
34 kneader
35 Assembly Machine
36 sieve selector
37 dryers
40 sintering machine
50 grinder
51 driven rolls
52 rotating shaft
53 Fixed Side Roll
54 rotating shaft
55 hopper

Claims (6)

As a grinding method of iron ore raw material using a roll mill,
Rio dose pellet feed, MBR, MBR-PF, which is harder than the first iron ore raw material, to the first iron ore raw material composed of at least one of crushed maramanba ore, fisorite, deceased blockman ore, serpentine, and pilbara blend. And mixing the second iron ore raw material consisting of at least one of lyodoce as a grinding aid having a mixing ratio of 10 to 45 mass%, and injecting the mixed first iron ore raw material and the second iron ore raw material into the roll grinder to grind. Grinding method of iron ore raw material characterized in that. The grinding | pulverization characteristic of the said 1st and 2nd iron ore raw material is a grinding | pulverization ratio defined as the reduction rate of the average particle diameter after grinding | pulverization with respect to the average particle diameter before grinding | pulverization, The said grinding | pulverization using said roll mill 2 The crushing ratio when the iron ore raw material alone is crushed is smaller than the grinding ratio when the first iron ore raw material is crushed alone using the roll mill. The iron ore raw material grinding method according to claim 1 or 2, wherein the average particle diameter before grinding of the second iron ore raw material is smaller than the average particle diameter before grinding of the first iron ore raw material. delete 4. The method of crushing iron ore raw materials according to claim 3, wherein the second iron ore raw material is a lyodoce pellet feed. delete

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