JP2003277838A - High crystal water ore used for sintering raw material for blast furnace, sintering raw material for blast furnace and its producing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To develop such a technique as to reduce the absorbing amount of water which does not contribute to a granulation function, for the purpose of performing a sintering operation using ore with a large amount of high crystal water and keeping high productivity. <P>SOLUTION: The ore with high crystal water 1 containing ≥4 mass% crystal water is blended with ≥5 mass% new raw material in a sintering raw material. In this case, the ratio of the grain having ≤1 mm diameter is adjusted so as to come into the range of 50-70 mass% by applying a prescribed treatment to the ore with high crystal water, e.g. a grading treatment with a crusher 2 and a screen, and this is mixed with the remained new raw material 3, powdery coke 5 (solid fuel) and returned ore 4, and granulated to prepare pseudo grain 18, and the sintering raw material is used and sintered by using a fire grate moving sintering machine 19. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention uses a high crystal water ore as a raw material for sinter ore used in a blast furnace ironmaking method,
In addition, the present invention relates to a technique for producing a sinter for a blast furnace in order to maintain high productivity in a sintering operation.

[0002]

2. Description of the Related Art Sinter ore used as a blast furnace raw material is generally produced by the following method. Iron ore powder of about 10 mm or less is piled up in a powder ore yard for each brand. A pile of various powdered ores, CaO-containing auxiliary raw material, SiO ₂ -containing auxiliary raw material, dust and the like are mixed by a bedding method at a preset ratio to obtain a blending powder. This blending powder, solid fuel such as limestone and / or quick lime, silica stone and / or serpentine, coke powder, etc., and return ores, and in some cases, each raw material such as plain powder ore, etc. Put in another raw material mixing tank, cut out a predetermined amount of each raw material continuously from each raw material mixing tank and mix, add an appropriate amount of water to the mixed raw material and mix, and further add appropriate water and mix・ Granulate into pseudo particles.

The pseudo-granular sinter raw material thus granulated is continuously fed from the hopper onto the pallet of the grate moving type sintering machine (Dwightroid type sintering machine), and 50
Raw material packed bed (sintered bed) with a height of 0 to 700 mm
To form. Next, in the ignition furnace, the solid fuel such as coke in the surface layer of the raw material packed bed is ignited, the solid fuel is burned while forcibly sucking air downward, and the combustion heat generated at this time converts the sintering raw material into Sinter and agglomerate. In the sintering process, the gas flow of which the air permeability is ensured by the combustion of the solid fuel in the raw material and the downward suction inside the sintering bed on the pallet and the heat transfer due to the movement of the combustion surface moving from the upper side to the lower side are performed. , The basic operation is to give it properly. Thus, maintaining good air permeability of the sintering raw material packed bed is essential for improving the productivity and quality of the sintered ore.

The sintered cake thus fired is crushed,
After cooling, the particles are sized to prepare particles having a size of 3 to 5 mm or more, and those satisfying the quality standard are charged into a blast furnace as “product sinter”. The rejected product that does not meet the quality standard and the powdered ore of 3 to 5 mm or less generated in the process of crushing and sizing the sintered cake are used again as a raw material for sintering as return ore.

The quality of the sinter produced in this manner has a great influence on the stability of the unloading state in the furnace during blast furnace operation, the air permeability and liquid permeability, the reduction efficiency and the high temperature properties. Therefore, in the production of sinter, the production conditions for securing high quality of the sinter are required, and in order to reduce the production cost, it is required to improve the product yield of the sinter, and further Improving productivity of mine is required.

The sinter for blast furnace thus obtained is
In order to ensure stable operation and productivity of the blast furnace, it is generally necessary that its quality characteristics have a predetermined level. That is,
The product sinter is required to secure its strength, reducing property and reduction pulverization resistance, and this also secures important factors for ensuring air permeability in the blast furnace. Stable operation and hot metal productivity will be secured.

On the other hand, in terms of iron ore supply, hematite (Fe ₂ O ₃ , hematite) and magnetite (Fe
High quality iron ores such as ₃ O ₄ and magnetite are reduced, and along with this, high crystal water content is high, such as pisolite ore or mara mamba ore that contains a lot of goethite (Fe ₂ O ₃ · nH ₂ O). The number of “high crystal water ores” is increasing. If the content of crystal water in the ore is high, it will reach about 10 mass%. There has been a strong demand for a technique of using such highly crystallized water ore in a large amount as a sinter for a blast furnace and advantageously.

However, the above-mentioned high crystal water ore is generally used as a raw material for producing a sintered ore due to its properties, particularly its high water content of crystallization as described above and its high porosity. There are various problems in use. This problem can be roughly classified into the following two points from the viewpoint of the disadvantages in the firing process and the raw material preparation process, which are peculiar to using the high crystal water ore in the sinter production process.

The first problem is that the highly crystallized water ore is caused by a local overmelting phenomenon at the time of initial melt formation in the firing process. Highly crystalline water ore is about 400-500 ℃
When it is heated to a large amount, a large amount of heat is consumed to remove the water of crystallization, and further, when the water is decomposed and dehydrated, coarse air holes and cracks are generated, and a porous property is added. Therefore, high crystal water ores have high reactivity in the sintering process, and
At around 200 ° C, highly fluid calcium-ferrite (CaO · 2Fe ₂ O ₃ ) -based melt was locally produced excessively, and it also burned in the sintering process due to inflow and solidification into coarse air holes and cracks. The air permeability in the binding bed deteriorates, and non-uniform pores remain in the sintered ore after firing, resulting in deterioration of the strength of the sintered ore. Therefore, the yield of the product sintered ore is deteriorated. Further, the air permeability in the sintering bed is deteriorated, so that the sintering rate is delayed and the productivity of the sintered ore is reduced.

The second problem is that the highly crystallized water ore is inferior in the granulation property of the pseudo particles prepared in the mixing / granulation step after the raw material is blended. As described above, in the sintering step, maintaining good air permeability in the sintering raw material packed bed (sintered bed) is extremely important for improving the productivity and quality of the sintered ore. Therefore, it is necessary for the pseudo particles forming the sintering bed to have an appropriate particle size. However, since the high crystal water ore has a high porosity, it is inferior in the granulation property of the pseudo particles prepared in the mixing / granulation step after blending the raw materials described above. The reason is that, in general, the water content in the mixed raw material requires that an appropriate amount of water is added as a granulation binder without excess or deficiency, and thus, at the same time as the pseudo particles having an appropriate particle size are granulated, Further, it is necessary for ensuring the air permeability of the sintering bed that the pseudo particles do not collapse during the sintering process. When an appropriate amount of water for exhibiting the binder function is added, a large amount of water that does not function as a binder because it is absorbed in the pores enters the inside of the structure of the high crystal water ore. Therefore, the air permeability of the sintering bed is deteriorated, the firing reaction is delayed, the productivity is reduced, and the excess fuel is evaporated to increase the sintering fuel ratio.

By solving both the first and second problems, the production of sinter can be carried out stably and at low cost with high quality sinter while ensuring high productivity. .
Conventionally, many solutions have been proposed that focus on the first problem, but few solutions that focus on the second problem.

Regarding the first problem (local overmelting), for example, Japanese Patent Publication No. 5-83620 proposes the following technique. Around the coarse grained high crystal water ore, a coating layer formed of high crystal water ore powder, MgO-SiO ₂ -based auxiliary raw material powder such as serpentine, and an appropriate amount of solid carbon powder such as fine coke is formed. In preparing the granulated product, the mixing ratio of the solid carbon powder, the value calculated by the two specific functions with the bound water content in the -1 mm high crystal water ore as a variable is set as the lower limit, Set within the range and contain MgO
The high-crystal water ore and the MgO-SiO ₂ containing high-crystal water ore so that the ratio of the weight% of the —SiO ₂ -based auxiliary material and the weight% of the high-crystal-water ore of −1 mm excluding the bound water falls within a predetermined constant range. A method is disclosed in which the mixing ratio of the system auxiliary material and the solid carbon powder is determined and mixed, and then the humidity is controlled and granulated and then mixed with another material. According to this method, this pre-granulated product, which is mainly composed of a highly crystallized water ore serving as a nucleus, is used as the other remaining raw material (this is a high CaO / SiO ₂ raw material in terms of the balance of raw material composition)
Pseudo-particles are prepared by mixing with the pre-granulated product and adhering it to the surface of the preliminary granulated product. By performing the pretreatment in this way, a CaO—Fe ₂ O ₃ -based melt is generated at around 1200 ° C. from the high CaO / SiO ₂ raw material forming the outer layer portion of the pseudo particles. When this CaO-Fe ₂ O ₃ -based melt reacts with the MgO-SiO ₂ -based auxiliary raw material that constitutes the coating layer of the preliminary granulated product surface layer, the melting point of this melt increases and the fluidity decreases. Therefore, it becomes difficult for the melt to enter the inside of the preliminary granulated product. Thus, the contact between the coarse-grained high-crystal water ore and the CaO—Fe ₂ O ₃ -based melt in the sintering process is suppressed, and the structure of the coarse-grained high-crystal water ore forming the nuclei is densified at a high temperature in the meantime. Is promoted by the combustion of powder coke and prevents the assimilation reaction of highly crystallized water ore by the melt. In this way, it is possible to prevent the reduction powdering resistance from deteriorating due to the generation of a large amount of coarse air holes described above, to ensure the air permeability in the bed of the sintering machine, and to improve the yield of the product sintered ore and the sintered ore. This is to maintain productivity (hereinafter referred to as "Prior Art 1").

Further, Japanese Patent Laid-Open No. 8-60258 discloses that
The following technologies have been proposed. The high crystal water ore is pre-granulated for a predetermined time (2 minutes) or more, and the fine powder in the high crystal water ore is attached to the core particles to perform a pretreatment to form pseudo particles. A small amount of general ore, an auxiliary raw material for sinter ore, and a solid fuel are mixed, and a mixed raw material to which water is appropriately added is prepared and granulated into a sintering raw material. In this method, high-crystal water ore reacts with limestone to generate a large amount of calcium-ferrite melt, and the dropping distance of the melt in the sintering bed becomes large. Melt reaches a region that has not risen sufficiently, is rapidly cooled to form a dense solidified shell,
It is intended to prevent the firing unevenness from occurring in the raw material packed bed, resulting in a decrease in the yield of the product sintered ore (hereinafter referred to as "prior art 2").

With respect to the second problem (granulation property), a technique has been proposed in which an appropriate amount of water added as a binder is determined in the mixing / granulation process of blended raw materials and the flow rate is controlled accordingly. For example, in Japanese Unexamined Patent Publication No. 11-61281, the formation mechanism of pseudo particles is modeled, and the following control is performed in order to form fine particles by adsorbing fine ore to coarse ores. That is, the lower limit water concentration value W _lmc , which has the ability of fine powder to adhere to coarse particles, is calculated from the water absorption rate (maximum water concentration capable of absorbing water) of the brand ore and its particle size composition, and is _{equal to} or greater than the W _lmc. As described above, the water concentration in the blended raw material is controlled, and the particle size distribution shape of the pseudo particles is 2 to 10 m.
The amount of water added is controlled so that the water in the blended raw material is obtained when the amount of pseudo particles within the range of m is maximized. In the technology disclosed in this publication,
For all iron ores including high crystal water ores, such a proposal has been made regarding an appropriate amount of water added in the granulation mixer to the compounding raw material for sintering (hereinafter, referred to as "prior art 3").

[0015]

In order to fully utilize the highly crystalline water ore as a sintering raw material, the above-mentioned first and second problems must be solved. First, the first problem is solved. In the prior arts 1 and 2, the process for preparing the sintering raw material is complicated and costly. In the prior art 2, since the coarse-grained highly crystallized water ore still remains, excess moisture that does not contribute to granulation is obtained. May be introduced, resulting in a decrease in sinter productivity and an increase in fuel ratio. And in particular, the solution of the second problem is delayed,
In the prior art 3 for the problem of (1), it takes a lot of trouble to control the water content of the sintering raw material with high accuracy, and it is considerably complicated, and the practical effect thereof remains questionable.

Therefore, the inventors of the present invention have a simpler raw material preparation operation than all of the prior arts 1 to 3 and have a problem in the initial melting of the raw material when using the raw material for sintering the highly crystallized water ore and an excessive amount of the raw material. A method that solves the problem of water absorption, in particular, even when a large amount of high crystal water ore is used, it prevents the carry-in of extra water that does not contribute to granulation and prevents the deterioration of air permeability of the sintering bed. (EN) Provided is a technique for producing a sinter for a blast furnace, which can suppress a decrease in the productivity of the sinter ore and an increase in the fuel ratio by eliminating the need for an extra fuel addition, or improve them. It was intended.

The inventors of the present invention can solve the problems of using a raw material for sintering highly crystallized water ore by a simpler raw material preparation operation in this way, and in order to investigate a method that can keep the cost low, The problems of water addition to ore and its absorption phenomenon were summarized.

1. As for the high crystal water ore in the blended raw material, most of the added water is absorbed by the porous part of the high crystal water ore, so the amount of water initially added as an appropriate amount as a granulation binder is insufficient. A tendency arises. This is because highly crystalline water ore with a porous property has a high water absorption capacity, but its water absorption rate is slow, so it is necessary to sufficiently absorb water to the inside of the ore structure and to exhibit the granulation binder function. It takes a long time to absorb a sufficient amount of water. Therefore, a large amount of extra water that does not contribute to the granulation action is brought into the mixed raw material. This extra water content increases as the blending ratio of the high crystal water ore increases.

2. Therefore, it is often difficult to uniformly add water to the high crystal water ore.

Therefore, the present inventors have taken up a method of adding a proper amount of water at the mixing / granulating stage of the blended raw materials. In solving this problem, the task is to find an effective water adjustment method with a simple operation, and thus to find an appropriate usage method in the sintering raw material of the high crystal water ore with the added water content adjusted. It was an issue.

[0021]

In order to solve the above problems, the present inventors have examined a method of stably and promptly adding an appropriate amount of water to a highly crystallized water ore. As a result, the reverse idea different from the conventional one, namely, performing appropriate crushing treatment on the high crystal water ore to destroy the pores in the high crystal water ore and appropriately adjust the particle size of the high crystal water ore. As a result, it was found that it is possible to reduce the amount of water that does not contribute to the granulation function absorbed into the highly crystallized water ore structure, and at the same time, to quickly and stably add water.

The present invention was made based on the above findings, and the gist thereof is as follows. The high crystal water ore used for the sintering raw material for blast furnace according to the invention of claim 1 is a high crystal water ore containing 4 mass% or more of crystal water,
The feature is that the particle portion of m or less is sized so as to fall within the range of 50 to 70 mass%.

In the sintering raw material for blast furnace according to the second aspect of the present invention, 4 mass of crystal water is sized so that the particle portion of 1 mm or less falls within the range of 50 to 70 mass%.
% Of high crystal water ore containing more than 5% of new raw material in sintering raw material
It is characterized in that it is obtained by mixing at least ass% and mixing it with the rest of the new raw material in the sintering raw material, solid fuel and return ore, and granulating.

In the present invention, "new raw material" means
From raw materials such as iron ore, which is a sintering raw material, auxiliary raw materials, which are substances containing SiO ₂ , CaO, MgO, etc., miscellaneous raw materials such as various slags and dusts, solid fuels such as coke and added water, etc. It refers to the one obtained by removing the three types of return ore returned from the binder, solid fuel for firing, and water added as appropriate.

In the blast furnace sinter according to the third aspect of the present invention, the blast furnace sintering raw material according to the second aspect of the present invention is obtained by firing using a grate moving type sintering machine. It is characterized by

According to a fourth aspect of the present invention, there is provided a method for producing a sinter for a blast furnace, which comprises mixing a high crystal water ore containing 4 mass% or more of crystallization water with 5 mass% or more of a new raw material in a sintering raw material. A method for producing calcination, wherein the high crystal water ore is subjected to a predetermined treatment so that the proportion of particles of 1 mm or less is 50 to 7
The high crystal water ore, which was prepared so as to fall within the range of 0 mass% and whose particle size was adjusted in this way, was mixed with the rest of the new raw material excluding the high crystal water ore, and solid fuel and return ore, Granulate to prepare a sintering raw material. It is characterized by firing using the sintering raw material thus obtained.

In the present invention, the water of crystallization is 4 mass%.
The iron ore containing above was taken up as a high crystal water ore,
This is because when the one containing 4 to 5 mass% or more of crystallization water is used, various problems as described above are usually caused. Further, when such a high crystal water ore is contained in the new raw material in an amount of 5 mass% or more, the above problem is caused,
If it is less than 5 mass%, there is almost no problem due to the water absorption of the high crystal water ore.

Further, a high crystal water ore having the above requirements for the content of water of crystallization and the mixing ratio is crushed by an appropriate means, and the particle ratio of particle diameter 1 mm under (-1 mm) is 5
The reason for the preparation to fall within the range of 0 to 70 mass% is as follows. That is, the particle ratio of -1 mm is 50 mass.
If it is less than 70%, the decrease in water absorption due to the pore destruction due to the crushing treatment of the highly crystallized water ore is small, while it is 70 ma.
If it exceeds ss%, the ratio of adhered particles to core particles becomes too large, making granulation difficult, and excessive water is required for granulation, making it difficult to achieve the intended purpose. Becomes Therefore, the high crystal water ore used in the present invention has a ratio of the particle portion of -1 mm of 50 to 70 ma.
It must be crushed and the particle size adjusted so that it falls within the range of ss%. Here, based on the relationship between the properties of the high crystal water ore by the ore brand to be crushed and the crushing conditions, the particle ratio of -1 mm occupying in the high crystal water ore only by crushing is When it is clear that the particle size distribution falls within the range of the particle size distribution condition of the invention (in the range of 50 to 70 mass%), only the crushing process is required, and the sizing process is not necessary.

Some high crystal water ores have a relatively large proportion of fine powder, depending on the brand, such as Mara Mamba ore, but the average particle size of high crystal water ores is generally 3 to 3.5 mm. Since it is a degree, by appropriately crushing the crushing of the part which is originally a fine powder ore, crushing is suppressed, so a fine powder having an excessively small particle size, for example, −
The proportion of the 0.125 mm particle portion does not significantly increase and becomes unsuitable. Therefore, the present invention can be widely applied to various brands of high crystal water ores. Further, in the particle size distribution after sizing, the ratio of -1 mm particles was specified because -1 mm is suitable as the boundary particle size from the viewpoint of pore destruction of the highly crystallized water ore.

[0030]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a flow chart for explaining the method for producing the sintering raw material for blast furnace of the present invention. High crystal water ore (crystal water content ≧ 4 wt%) 1 is crushed and sized by a crusher 2. The treatment condition was a preliminary test according to the grain size distribution of high crystal water ore by brand and lot.
Understand and set the crushing and sizing conditions so that they fall within the range of 0 to 70 mass%. In this way, a high crystal water ore 1'having a predetermined particle size distribution is prepared. On the other hand, the remaining new raw material 3 other than the highly crystallized water ore 1, return ore 4 and powder coke 5 as a solid fuel are cut out from each raw material mixing tank 6. Here, the remaining new raw material 3 is a blending powdered ore 7 consisting of a normal ore 24 which is an iron ore with a crystallization water of less than 4 mass%, limestone 8 or quicklime 9 as a CaO-containing substance, nickel slag 10 as a SiO ₂ -containing substance, etc. , And a scale 11 as a miscellaneous raw material.

However, in the above, in the case of specific conditions,
That is, when the blending ratio in the new raw material of the high crystal water ore 1 is set relatively high (for example, about 50 to 80 mass%), the blending powder ore 7 in the remaining new raw material 3 contains:
A high crystal water ore (for example, 4 to
6 mass% is a small percentage (for example, 10 mass)
There is no problem even if it is contained (about s% or less), and the action and effect of the present invention are exhibited.

The above new raw material 3, return ore 4 and powder coke 5 are mixed in a predetermined ratio. As for the blending, each raw fuel is blended in a predetermined ratio so that the high crystal water ore 1 in the new raw material is 5 mass% or more, and the moisture 12 is added as a binder.
Mix with a drum mixer 13 or the like. Then, water 14 is appropriately added and granulated by the disk pelletizer 15 or the drum type granulator 16. The coke powder may be granulated and then covered with a drum mixer 23 to cover the particle surface. In this way, the pseudo particles 18 which are the sintering raw material are prepared. The obtained sintering raw material is charged into a grate moving type sintering machine 19 and fired to produce a sintered cake 20. The sintered cake 20 is crushed and sized to obtain a sintered mineral product 21, which is conveyed to the blast furnace 22 as a raw material. In addition, the sintered ore having a predetermined grain size or less is returned to the raw material mixing tank 6 as the return ore 4.

In the flow of preparing the sintering raw material, the high crystal water ore 1 is crushed and sized in advance, and the obtained high crystal water ore 1 is blended with other ores in the ore yard to obtain the high crystal water. Prepare blending ore powder containing ore 1 and bring it into raw material mixing tank 6 separately,
You may mix with other new raw materials 3 grade. Alternatively, the highly crystallized water ore 1 may be transported to the sinter plant alone, crushed and sized in the sinter plant line, and charged into the raw material mixing tank 6. Further, the method of crushing and sizing the highly crystallized water ore 1 and the method of mixing the raw materials after blending and granulating do not need to be specified as long as the requirements of the present invention are satisfied. In addition, the water content of the pseudo particles 18 granulated from the mixed raw material, the addition amount of the powder cokes 5 and 17, and the particle size are also within a range in which the quality of the sinter and the productivity can be maintained. There is no particular limitation.

If there are a plurality of high crystal water ores 1 to be subjected to the crushing and sizing operations, the high crystal water ores of each brand may be treated, or 2 of the plural brands may be treated. The high crystal water ore after blending the seeds or more may be treated. In any case, granulator 15
Alternatively, a predetermined crushing and sizing treatment may be performed before granulation in 16.

Further, in the present invention, the operation of adding water to all highly crystallized water ores 1'after crushing and sizing is
It is necessary to do it after the high crystal water ore 1'has been adjusted to a predetermined grain size. This is because, if water is added to the high crystal water ore before crushing the pores due to crushing, excess water that does not contribute to granulation is absorbed in the structure of the high crystal water ore. Therefore, sprinkling water may be performed in the fine ore yard to prevent dust generation from the high crystal water ore, but the high crystal water ore before crushing may be sprayed from the fine yard to the storage tank (not shown) before the crushing process. No water should be added on the transfer device (not shown) during transfer to or in the reservoir.

[0037]

EXAMPLES The present invention will be described in more detail by way of examples.

Examples 1-1 and 1-2 which are production tests of sinter using the method for preparing a sintering raw material within the scope of the present invention.
And a comparative example 1-1 and 1-2 belonging to a conventional method, which is a production test of a sintered ore according to the invention outside the scope of the present invention, and an ore obtained by crushing a high crystal water ore into excessively fine particles. Comparative Examples 2-1 and 2-2 were performed using as a sintering raw material. All of these tests were performed using a sintering pot tester.

In all the tests, high crystal water ores containing about 10 mass% of water of crystallization as shown in Table 1, and pisolite ores Lobe River (ROB) and Yandy (YAN) were used. The compounding ratio of these high crystal water ores in the new raw material is the same in all tests, and the total of ROB and YAN is a constant level of 40.3 mass%,
The coke powder addition rate as a solid fuel is 4.5 and 4.
It is set to two levels of 3 mass% (however, the ratio of the external number to the new raw material), and the mixed raw material water content (water content in the sintering raw material after preparation of the pseudo particles and before charging into the sintering machine) is 7.0 and 6.0, respectively. The test was conducted at two levels adjusted to be 5 mass%.

[0040]

[Table 1]

On the other hand, regarding the particle size of the highly crystallized water ore, in Examples 1-1 and 1-2, it was crushed and sized to obtain R
The -1 mm particle portion in each of OB and YAN was adjusted to 58 and 51 mass%.
On the other hand, Comparative Examples 1-1 and 1- which are examples of the conventional method
In No. 2, high crystal water ore ROB and YAN were used as they were without crushing and sizing treatment, and in Comparative Examples 2-1 and 2-2, high crystal water ore ROB was used. -1m in each of YAN and YAN
The particle portion of m was 74 and 75 mass%, and those prepared at a high rate outside the condition range of the present invention were used. Table 2
The examples of particle size distributions of the high crystal water ores ROB and YAN used in these tests are shown in FIG. And Table 3
Shows the mixing ratio of the sintering raw material, the water content of the mixed raw material, and the ratio of the -1 mm particle portion in each of the high crystal water ores ROB and YAN in each test.

[0042]

[Table 2]

[0043]

[Table 3]

As described above, the water content is adjusted by appropriately adding water to the raw material 25 containing the new raw material, the return ore and the coke powder, and the sintering pot test apparatus is shown in the schematic diagram of FIG. Then, a pseudo disc 27 was prepared by mixing and granulating with a test disc pelletizer 26, and the obtained sintering raw material was loaded into a sintering pot tester 28.

The sintering pot testing machine 28 is equipped with a pot furnace 28a having an internal volume of the raw material charging portion of 280 mmφ × 450 mm height, and the sintering raw material bed inside the pot is ignited for 90 seconds at the upper surface temperature of the raw material bed. Was adjusted to reach 900 ° C. During the subsequent firing, the atmospheric pressure difference between the upper and lower surfaces of the raw material bed was maintained at 9800 N / m ² .

In the above-mentioned sintering test process, the pseudo particles were sampled just before charging into the sintering pot tester, and the pseudo particle size of the mixed raw material was measured. Then, the yield and production rate of the sintered mineral product after sintering were investigated, and the quality test of the sintered ore was performed.

Table 4 summarizes the mixed raw material pseudo-particle size and the production rate.

[0048]

[Table 4]

From the above test, the following matters can be understood.

In Examples 1-1 and 1-2, since the highly crystallized water ore was made finer and was absorbed by the highly crystallized water ore portion in the conventional coarse grain state, the granulation of the sintering raw material was performed. It was possible to improve the pseudo particle size of the mixed raw material by effectively utilizing the water that did not contribute to the. Thereby, the effect of improving the air permeability of the sintering bed at the time of sintering the raw materials is exhibited, and the compounding ratio of the high crystal water ore is higher than that of Comparative Examples 1-1 and 1-2 used in the conventional method of using the high crystal water ore. Even if the number of sinters is increased significantly, the sinter ore production rate is improving while ensuring the quality level of sinter. And, even when the mixed raw material water content and the coke blending ratio were simultaneously reduced in the present invention (Example 1-2), the sinter ore production rate was not reduced in the conventional method when the mixed raw material water content and the coke blending ratio were not reduced. Higher than the sinter production rate in Example 1-1.

On the other hand, in Comparative Examples 2-1 and 2-2, since the highly crystallized water ore was refined to the extent that it was outside the scope of the present invention, the granulation was not sufficiently performed, and therefore the sinter production rate was high. However, the result was lower than Comparative Examples 1-1 and 1-2 by the conventional method.

As described above, in order to improve the granulation property of the sintering raw material by the pore destruction of the highly crystallized water ore and improve the production rate of the sintered ore, the degree of the pore destruction is within an appropriate range. It turns out that it is necessary to fit in.

[0053]

As described above, according to the present invention, a high crystal water ore having a crystal water content of 4 mass% or more is crushed and sized in advance so as to satisfy an appropriate particle size condition. Alternatively, by crushing and using this as a sintering raw material, even if the high crystal water ore is used in a large amount of 5 mass% or more, the productivity of the sintering is reduced while ensuring the quality of the sintered ore. It is possible to suppress or improve the increase in the fuel ratio. It is possible to provide a method for producing such a sinter for blast furnace, and to bring about an extremely beneficial effect industrially.

[Brief description of drawings]

FIG. 1 is a schematic flow chart of an entire sinter ore manufacturing process for explaining an embodiment of the present invention.

FIG. 2 is a schematic diagram showing a sintering pot testing device.

[Explanation of symbols]

1 Highly crystalline water ore 1'Highly crystalline water ore (after crushing and sizing) 2 crusher limestone 3 balance new raw material 4 Return ore 5 powder coke 6 raw material mixing tank 7 Blending powder ore 8 limestone 9 quicklime 10 Nickel slag 11 scale 12 Moisture 13 drum mixer 14 Moisture 15 Disc pelletizer 16 drum type granulator 17 powder coke 18 pseudo particles 19 Grate moving sintering machine 20 Sintered cake 21 Sintered mineral products 22 Blast furnace 23 Drum mixer 24 Normal ore 25 raw materials 26 Test Disc Pelletizer 27 pseudo particles 28 Sintering pot tester 28a pot furnace 28b ignition burner 28c Suction blower

Claims (4)

[Claims] 1. A high crystal water ore containing 4 mass% or more of crystal water, wherein a particle portion of 1 mm or less is 50 to 70 ma.
A highly crystallized water ore used as a sintering raw material for a blast furnace, characterized by being sized to fall within the range of ss%. 2. The particle portion of 1 mm or less is 50 to 70 ma.
A high crystal water ore containing 4 mass% or more of crystal water, which is sized so as to fall within the range of ss%, is used for 5 mass% or more of the new raw material in the sintering raw material. Mixing with the balance of the new raw material and solid fuel and return ore,
A sintering raw material for a blast furnace, which is obtained by granulation. 3. A blast furnace sinter, wherein the blast furnace sintering raw material according to claim 2 is fired using a grate moving type sintering machine. 4. A method for producing a sinter for a blast furnace, which comprises blending a high crystal water ore containing 4 mass% or more of crystal water in an amount of 5 mass% or more of a new raw material in a sintering raw material. And the ratio of particles of 1 mm or less is 50 to
The high crystal water ore, which was prepared so as to fall within the range of 70 mass% and whose particle size was adjusted in this way, was mixed with the rest of the new raw material, solid fuel and return ore, and granulated to obtain a sintering raw material. A method for producing a sintered ore for a blast furnace, which comprises preparing and sintering the thus obtained sintering raw material.