KR20040083346A - manufacturing process for sintered ore - Google Patents

Abstract

PURPOSE: To provide a method for manufacturing sintered ore without deterioration of productivity and product recovery ratio even though porous ore having high porosity containing much of fine grains as water of high crystallization and low gangue is used as a raw sintering material. CONSTITUTION: The method comprises the steps of preparing a blend by blending porous ore having high porosity containing 3.0 mass% or more of water of crystallization, 4.0 mass% or less of SiO2 and 20 mass% or more of fine grains having a grain diameter of 0.25 mm or less with ore in which a ratio A1(mass%) of grains having a specific surface area of 3 m¬2/g or more and a grain diameter of 3 mm to less than 5 mm to the porous ore having high porosity and a ratio A2(mass%) of grains having a grain diameter of 5 mm to less than 10 mm to the porous ore having high porosity satisfy the following relational expression(1):£Relational Expression(1)|13.2-0.014xA1+0.033xA2<14.5; mixing and granulating the blend at a certain agitation speed or more; and sintering the mixed and granulated blend.

Description

Manufacturing process for sintered ore {manufacturing process for sintered ore}

The present invention provides a sintered ore which is useful for producing high quality sintered ore using ore such as maramamba ore, which is composed of inferior quality of porous water having a high content of crystal water and having a lot of fine powder. It relates to a manufacturing method.

In the sintered ore, _secondary raw materials such as limestone, quartzite, serpentine are mixed with iron ore so that the basicity (CaO / SiO ₂ ) and SiO ₂ content are the target values, and the raw materials to which solid fuel is added are mixed and assembled with a dream mixer and disk palletizer. It is then obtained by firing with a sintering machine.

It is known that productivity and product recovery rate deteriorate when conventionally mixing and sintering iron ore containing high concentration of crystalline water in a small amount. It is also well known to deteriorate productivity and product recovery rate even when a large amount of fine iron ore is blended. However, iron ore raw materials tend to be inferior in quality depending on the raw material situation, so that the ratio of phisorite ore with high crystal water but relatively fine powder and high crystal water content and high fine powder, for example, The development of increased sintered ore has been an extremely small task.

When the content of crystal water in the blended raw material is increased, an extra amount of heat for decomposing and evaporating the crystal water is needed, which necessitates an increase in the amount of solid fuel added. If the amount of solid fuel added is not increased, the sintered bed will be in a heat deficient state, and the quality of the product sintered ore will be deteriorated, and the semi-gloss will be increased, resulting in a decrease in product recovery.

On the other hand, when the amount of solid fuel added is excessively large, the red zone of the sintered bead becomes wider and the melt is formed excessively, and the air permeation resistance of the sintered bead is increased, resulting in a decrease in productivity and a poor product recovery rate. .

In addition, when a large amount of raw ore having a high fine powder content is used, the granulation property of the blended material is deteriorated, the air permeability of the sintered bed is deteriorated, and productivity is lowered. In addition, since the air permeability deterioration part and the plasticity of the lower part become insufficient, the recovery rate of the product also deteriorates.

In addition, since maramamba ore has less SiO ₂ content than other raw materials, when an ore such as maramamba ore is used as a raw material for sintered ore, when the basicity (CaO / SiO ₂ ) of the sintered ore is constant, It is well known that the amount of CaO decreases as the SiO ₂ decreases, so that the amount of crude material necessary for sintered ore formation is insufficient, and the product recovery rate and strength of the sintered ore deteriorate.

In addition, since the maramomba ore is a porous ore with high porosity like the pesorite ore, when the maramomba ore is used, a part of the moisture added at the time of granulation penetrates into the pores, and the fine ore is assembled into the granulated ore. Since the water to be adhered is insufficient, the granulation property of the blended raw material is deteriorated, resulting in reduced productivity, product recovery rate and cold strength.

That is, even when the granular moma ore, which is a porous fine raw material having a fine particle diameter of 0.25 mm or less (usually 20 mass% or more), is assembled with the granulation raw material and high moisture, since the adhesion to the granular raw material is weak, the pseudo particle of the raw raw material Since the strength is lowered, there is a problem of differentiating during transport to the sintering machine, decomposing upon drying in the sintered bed, deteriorating the air permeability of the sintered bed, and lowering productivity and product recovery rate.

Various techniques for solving the above-described problems have been proposed so far, and as a manufacturing method of a sintered ore using iron ore containing a lot of fine powder, Japanese Patent Nos. 2953308, 10-280058, and 10-317069 Japanese Patent Laid-Open No. 11-61282 discloses Japanese Laid-Open Patent Publication No. 2002-235121 as a method of using a maramom bar ore having a high crystal water content and high fine powder.

Among them, Patent No. 2953308 discloses, "A blade blade for high speed agitation which contains a sintered raw material which contains 30 mass% or more of particles having a particle diameter of 0.5 mm or less and is mixed so that the SiO ₂ content of the sintered ore is 3.0 to 4.7 mass%. Is sintered after mixing in a built-in mixer.

Japanese Unexamined Patent Publication No. 10-280058 discloses that "a method of processing a sintered raw material containing 2 mass% or more of Al ₂ O ₃ and containing 80 mass% or more of particles having a particle diameter of 1 mm or less, wherein a part of the sintered raw material is used. One or two or more of the dry dust and the wet dust collected by the dust collector and the dust of water and slurry are added to the target moisture, so that the target moisture is moistened, mixed, After granulation, a method of mixing or mixing granulation with the rest of the sintered raw material is proposed.

Japanese Unexamined Patent Publication No. 10-317069 discloses that after pre-assembling (preferably with a high speed stirring mixer) by adding one or two or more of fine iron ore and dust to a part of the sintered raw material cut out from the raw material tank. A method of treating a sintered raw material in which granulated materials are mixed or mixed with the remaining sintered raw materials cut out from the raw material tank, wherein the raw materials provided in the pre-assembly process satisfy the following conditions, AL ₂ O ₃ content ≤ 2 mass%, content ≤ 50 mass%, and crystal water content ≥ 5 mass% in ore with a particle diameter of 1 mm or less.

Japanese Patent Laid-Open No. 11-61282 discloses that "a sintered raw material containing 30 mass% or more of particles having a particle diameter of 0.5 mm or less, and that the SiO ₂ concentration of the sintered ore is 2.8 to 4.7 mass% is mixed and assembled by a high speed stirring mixer. And a method for producing a sintered ore characterized by sintering after adding a fuel component and re-assembling.

On the other hand, Japanese Patent Application Laid-Open No. 2002-23512 discloses that "a high-crystallized water or a low-graphite pearl ore containing fine powder of 3.0 mass% or more, SiO ₂ or less 4.0 mass% or less and a particle diameter of 0.25 mm or less 25 mass% or more (for example, A method for producing a sintered ore by mixing semi-oral and solid fuel with new raw materials containing 5% by mass or more and 50% or less of maramamba ore by charging the mixed raw material into a sintering machine and firing the same. A method for producing a sintered ore characterized in that a mixture or a mixture of granules and a porous pyriteite ore is mixed with the blended raw materials and granulated and sintered.

The maramamba ore is porous like pisorite ore, and since some of the moisture added during assembly penetrates into the pores and lacks moisture to attach the fine ore to the surface of the granulated ore, the granularity is higher than that of other ordinary ores. Inferior Therefore, using a method described in Japanese Patent Nos. 2953308, 10-280058, and 11-61282, a whole or part of a sintered raw material containing a large amount of finely divided maramamba ore is subjected to a high speed stirring mixer. Even in the case of mixing and assembling, the fine ore cannot be sufficiently adhered to the surface of the granulated ore, and the strength of the granulated product cannot be significantly improved.

In addition, in the method disclosed in Japanese Patent Application Laid-Open No. 10-317069, assemblability is improved by mixing and assembling a highly granular ore (e.g., physoreite ore) and finely divided ore with a large number of granules in advance using a high speed stirring mixer. There is this. However, in the case of using a porous maramamba ore having high absorption as finely divided ore, there is a problem that the strength of the granulated material sufficiently high is not obtained simply by applying the conditions of this method. In addition, since the maramamba ore is a low vein (especially low SiO ₂ content), simply applying this method conditions reduces the amount of sintered ore, there is a problem that the product recovery rate can not be maintained.

On the other hand, in the method of Unexamined-Japanese-Patent No. 2002-235121, the granulation property is expected to be improved by mixing and assembling the fissolite ore and maramamba ore, which are often granulated as nuclear particles in advance. However, the mixing and assembling means are not specifically mentioned, and it is difficult to add sufficiently high granulated strength because it is difficult to add sufficient moisture due to the characteristics of the device by using an ordinary dream mixer or the like. there is a problem.

The present invention is to solve the problems in the prior art, the object of which is that the sintered ore does not deteriorate the productivity and product recovery even when using a marathon bar ore as a sintered ore raw material that contains a lot of fine crystalline water, low-graphite fine powder To provide a method of manufacturing.

Fig. 1 is a bar graph showing the comparison of the measurement results of the packed bed breathability index JPU of sintered raw materials adjusted under the conditions of Example 1-1 of the present invention.

2 is a bar graph showing a comparison of the sintering time of the sintered raw materials adjusted under the conditions of Example 1-1.

Figure 3 is a bar graph showing the production rate of the sintered raw material adjusted under each condition of Example 1-1.

4 is a graph showing the relationship between the specific surface area of the mixed ore and the packed bed breathability index JPU.

5 is a graph showing the relationship between the specific surface area and the firing time of the blended ore.

6 is a graph showing the relationship between the specific surface area and production rate of blended ores.

7 is a graph showing the effect of the particle ratio of the particle size of 3mm or more and less than 5mm in the baking ore in the firing time.

8 is a graph showing the effect of the particle ratio of 3mm or more and less than 5mm in the production ore in the mixed ore.

9 is a graph showing the effect of the particle ratio of 5 mm or more and less than 10 mm in the mixed ore on the firing time.

10 is a graph showing the effect of the particle ratio of 5 mm or more and less than 10 mm in the production ore in the mixed ore.

Fig. 11 is a graph showing the relationship between the ratio of the fine powder of ˜0.5 mm and the cold breathability index JPU in the formulation consisting of maramamba ore and hematite ore.

FIG. 12 is a graph showing the relationship between the pulverization time and the ratio of ˜0.5 mm of a mixture composed of maramamba ore and hematite ore.

(Means to solve the task)

In order to solve the above-mentioned problems, the first method of the present invention has a Maramamba ore containing 3.0% by mass or more of crystal water, 4.0% by mass or less of SiO ₂ , and 20% by mass or more of fine powder having a particle diameter of 0.25 mm or less. The specific surface area is 3 m 3 / g or more, and the relationship between the proportion A ₁ (mass%) of particles having a particle size of 3 mm or more and less than 5 mm and the particle ratio A ₂ (mass%) of 5 mm or more and less than 10 mm is expressed by the following formula (1) It has the point that it is made into the compound which mix | blended ore which satisfy | fills the compound, and this compound is sintered after mixing and assembling at predetermined stirring speed or more. In this method, it is preferable that the compounding quantity of the ore to mix | blend with maramamba ore is 20-60 mass parts with respect to 100 mass parts of maramamba ores. Moreover, it is good to carry out 5-10 mass% of water content in the said compound.

13.2-0.014 × A ₁ + 0.033 × A ₂ 〈14.5 ‥‥‥‥ (1)

Here, the "specific surface area" as used in the present invention means the surface area per ore unit mass.

According to the second method of the present invention, which can solve the above problems, the crystal water is added to the maramamba ore containing 3.0 mass% or more of crystal water, 4.0 mass% or less of SiO ₂ , and 2.0 mass% or more of fine powder of 0.25 mm or less. -4.0 mass%, hematite ore containing 3.0 mass% or more of SiO ₂ and less than 20 mass% of fine powders of 0.25 mm or less is added, and SiO ₂ is 3.0-5.0 mass% and the fine powder of 0.5 mm or less is 25% or more It is a manufacturing method of a sintered ore characterized by sintering after mixing and mixing this compound at a predetermined stirring speed or more as a compound made into less than 30 mass%.

Moreover, in the said 1st, 2nd invention, it is preferable to make the water content of the said compound into 5-10 mass%.

In the present invention of the above 1 and 2, in order to obtain the required compound stirring speed, it is necessary to use a high speed stirring mixer. Specifically, an agitator rotational speed of 891 rpm and a fan rotational speed of 47 rpm are required by using a high speed stirrer of an Eirich mixer-RO ₂ (manufactured by Eirich, Germany).

The present invention provides a method for producing a sintered ore that does not deteriorate productivity and product recovery even when a porous maramamba ore containing a large amount of fine powder in high crystal water and low gangue is used as a sintering raw material.

(The best form to carry out invention)

First, the first invention of the present application will be described.

The present inventors examined at various angles in order to achieve the said objective. As a result, ore in which the specific surface area and the particle size distribution (particle size composition) are appropriately adjusted to maramamba ore containing 3.0 mass% or more of crystal water, 4.0 mass% or less of SiO ₂ , and 20 mass% or more of fine particles having a particle diameter of 0.25 mm or less. When the mixture is added to the mixture, and an appropriate amount of water is added to the mixture, the mixture is granulated at a predetermined stirring speed or more, and the granulation performance is improved by one layer as compared to the maramom bar ore alone, which is poor in granulation performance. The particle size and pseudo particle strength were found to increase.

Then, by sintering the blended raw materials as described above, the sintered bed, that is, the air permeability in the sintering process is improved, the firing is greatly improved, productivity and product recovery rate is further improved to complete the present invention.

In the present invention, the specific surface area of the ore (hereinafter referred to as "blended ore") blended into the maramom bar ore needs to be 3.0 m 2 / g or more. If the specific surface area is less than 3.0 m 2 / g, the surface of the ore is slippery, which makes it difficult to retain moisture on the surface, and as the surface irregularities become smaller, the amount of finely attached fine powder is reduced. For this reason, the granulation properties deteriorate, the air permeability of the sintered ore filling layer deteriorates, the sintering time becomes long, and the productivity decreases. However, if this specific surface area becomes too large, the proportion of moisture sucked into the pores on the surface increases, requiring a larger amount of water, so that the amount of moisture introduced into the sintered filling layer increases, and as a result, the air permeability of the packed layer during sintering Since it worsens and productivity falls, it is recommended to set it as 3.0 m <2> / g or less.

In the present invention, a compounded ore is used as a relatively granulated one, but this particle size configuration is also an important requirement. As discussed by the present inventors, ore having a particle size (meaning the maximum particle diameter) in the blended ore, in particular, 3 mm or more and less than 5 mm, and ore having a particle size of 5 mm or more and less than 10 mm affects the granulation. It was found that the above object can be achieved if these compounding ratios are properly adjusted to satisfy the following formula (1). In addition, this formula (1) is calculated | required by the multiple regression analysis method based on the result which the inventors etc. experimentally examined about the effect which the granularity in a compound ore has on granulation property etc. In addition, in order to realize such granularity, the ore can be sieved.

13.2-0.014 × A ₁ + 0.033 × A ₂ 〈14.5 ‥‥‥‥ (1)

However, A ₁ : particle ratio (mass%) of 3 mm or more and less than 5 mm

A ₂ : Grain ratio (mass%) of 5 mm or more and less than 10 mm

Respectively.

In the present invention, it is necessary to stir-mix the mixture after adding moisture to the blend in order to achieve a predetermined stirring speed or higher. The reason for employing such a configuration is as follows. That is, in the high speed stirring mixer, the added moisture penetrates through the mixture due to the strong mixing force of the stirring blades, and a water film is formed on the surface of the fine particles. For this reason, the plasticity of the fine particles is improved, and the fine particles are easily attached to the surface of the compounded ore (particle to be the nucleus), and the fine powder which is freed is surely reduced. As a result, the average particle diameter and the pseudo particle strength increase, and the air permeability during the sintering bed, that is, the sintering process is greatly improved, and the productivity and the product recovery rate are improved.

On the other hand, in the case of using a conventional drum mixer and a disc palletizer rather than a high speed agitating mixer, the mixing power is weak so that there is not enough water on the surface of the fine particles, so that the plasticity is insufficient, and the fine particles cannot be sufficiently attached to the surface of the mixed ore. do. As a result, a large amount of free fine powder may remain, or there may be regions where excess moisture is partially formed, and the fine powder may be slurried.

It is preferable to adjust the water content of the compound which is the sintering raw material of this invention so that it may become 5-10 mass%. When this moisture content is less than 5 mass%, the moisture content will be insufficient, and the plasticity of the said fine particle will not fully be obtained, and granulation property will fall.

On the other hand, when the moisture content exceeds 10% by mass, excess moisture is caused, so that the air permeability in the sintering process is lowered. The lower limit with more preferable water content in a blended raw material is about 7.5 mass%, and a more preferable upper limit is about 9.5 mass%.

In addition, about 7 mass% of the moisture content in the conventional sintering raw material is a limit. Under such water content, mixing and assembly are possible with the drum mixer and the disc palletizer. However, when the water content is 8% by mass or more, the drum mixer and the disc palletizer alone cannot achieve sufficient agitation. It was. In contrast, with a high speed agitating mixer, a moisture content of up to at least 10% by mass can be assembled without problems.

In the present invention, the marathon bar ore and ore having a predetermined property is mixed and stirred to form a sintered raw material, but prior to sintering, ores and raw materials having different general properties with respect to such sintered raw materials ( For example, lime, silica, etc.) may be blended and stirred to obtain a final sintered raw material. In addition, a high speed stirring mixer may be used for mixing and mixing ores and other raw materials having other general properties, and an object of the present invention can be achieved by mixing and stirring with a conventional drum mixer.

Moreover, it is preferable that the compounding quantity of a compounding ore is about 20-60 mass parts with respect to 100 mass parts of maramamba ores.

Next, a second invention of the present invention will be described.

When used in a decision to be 3.0 mass% or more, SiO ₂ 4.0% by mass or less, the differential of less than 0.25mm to sinter the Mara mamba ore containing 20 mass% or more ventilation is deteriorated. Therefore, assemblability (造粒性) was added to a bad Mara mamba ore, hematite ore containing a predetermined number of 2.0 to 4.0 mass%, SiO ₂ 3.0% by mass or more and less than 20% by weight of the fine powder of less than 0.25mm in SiO ₂ is 3.0 to 5.0% by mass, and a fine powder of 0.5 mm or less is 30% by mass, and an appropriate amount of water is added to the compound to be mixed and granulated at a predetermined stirring speed or higher. As a result, a part of the fine powder of the maramamba ore adheres to the open pores of the relatively porous hematite ore, and the amount of free fine powder decreases, resulting in a mixed granule having less fine powder. By sintering this mixed assembly, the sintered ore of the present invention is obtained.

Solid fuel and other ores may be added to the mixed assembly, and then mixed and granulated again to form a blended raw material. As a result, the pseudo particle average diameter and pseudo particle strength of the blended raw material increase. By sintering this blended raw material, the air permeability during the sintering bed, that is, the sintering process is improved, and the firing is greatly improved, thereby improving the production rate and product recovery rate.

Here, the selection of hematite ore containing 2.0 to 4.0 mass% of crystal water as an object to be added to the maramom bar ore is relatively large open pores on the surface thereof, so that fine powder adheres to or is blocked. Because it is easy. In addition, the crystal water content of hematite ore is 2.0 to 4.0 mass% because it has sufficient open pores on its surface, and it is preferable that the concentration of crystal water in the compound with maramamba ore is not excessive. . In addition, since the SiO ₂ content in hematite ore was 3.0 mass% or more because the SiO ₂ content of maramamba ore is lower than other raw materials ores, when the SiO ₂ content of hematite ore is too low, This is because discretion cannot be secured. Furthermore, the fine fraction of hematite ore 0.25 mm or less is set to less than 20% by mass in order to ensure the proportion of nuclear particles with large particle diameters and to avoid excessive free fine fractions that do not adhere to the open pores of hematite ore. .

In addition, the SiO ₂ content of the compound in which hematite ore was added to maramamba ore was 3.0 to 5.0% by mass because the amount of sintered ore was insufficient and the strength was lowered at less than 3.0% by mass, exceeding 5.0% by mass. This is because the amount of slag generated in the blast furnace becomes excessive when the sintered ore is used in the blast furnace. In addition, the fine powder of 0.5 mm or less of the blend was made 25 mass% or more and less than 30 mass% by less than 25 mass% as the amount of granulated ores became too large, resulting in an increase in the collision frequency of the granulated ores. This is because the rate at which the once-attached fine ore peels off due to the collision between the granulated ores becomes greater than the rate at which the fine ore attaches to the granulated ore, thereby impairing pseudo particle formation. On the other hand, if it is 30 mass% or more, the amount of free fine powder is increased to inhibit pseudo particle formation, the air permeability in the sintering process begins to decrease, and adversely affects the production rate and product recovery rate.

It is necessary to use a high speed stirring mixer in order to make the stirring speed in the mixing and assembling more than a predetermined speed after adding water to the compound. This is for the following reason. That is, with the strong mixing force of the high speed stirring blades provided in the high speed stirring mixer, the added moisture penetrates into the entire mixture, and the water film is formed on the surface of the fine particles. This improves the plasticity of the fine particles, easily adheres to the open pores of the hematite ore, and freely reduces the fine powder. As a result, the pseudo particle average diameter and the pseudo particle strength increase, so that the air permeability in the sintered bed, that is, the sintering process is improved, and the firing efficiency is greatly improved, thereby improving production rate and product recovery rate. On the other hand, when a conventional dream mixer and a disc palletizer are used instead of a high speed stirring mixer, the mixing power is weak. Therefore, moisture cannot pass on the surface of the fine particles, and plasticity is insufficient, so that it is not sufficiently attached to the open pores of the hematite ore. As a result, a large amount of free fine powder remains.

It is preferable to adjust the moisture addition amount so that the moisture content of a mixture may be 5-10 mass%. If the amount of water is less than 5% by mass, the plasticity of the fine powder is not sufficiently obtained, and the granulation property is lowered. If it exceeds 10% by mass, the moisture becomes excessive, so that the air permeability decreases during the sintering process. The recommended range of water content of the blend is 7.5 to 9.5 mass%.

On the other hand, the water content of the conventional sintered raw material is about 7 mass% normally. Although it is possible to mix and assemble with a drum mixer and a disc palletizer, it is known that when the moisture content is 8% by mass or more, assembly is difficult for the drum mixer and the disc palletizer. On the other hand, in a high speed stirring mixer, at least 10 mass% of moisture content can be assembled without a problem.

As described above, the mixed granulated mixture of maramamba ore and hematite ore in advance is mixed with other compounding materials and assembled into a sinter hopper of a sintering machine, and then pelleted by a drum feeder or the like. After charging the furnace, the sintering bed surface was ignited in an ignition furnace, and the sintering under the sintering bed was sucked by a suction blower, and the sintering work was performed.

Hereinafter, the present invention will be further described in detail as an embodiment. The following examples do not limit the present invention, and any modification of the design is within the technical scope of the present invention in view of the preceding and the later gist.

EXAMPLE

An embodiment according to the first invention will be described.

Example 1-1

First, the present inventors confirmed the effect of high speed stirring on the formulation containing the maramamba mixed ore. Using various raw materials ores of the chemical components shown in the following Table 1, these were blended in the blending ratio shown in the following Table 2 to obtain a sintered raw material. In Table 1, ore W corresponds to maramamba ore. In addition, the compounding procedure in No. 1-No. 4 of Table 2 is as follows.

(1) No. 1: After mixing the raw materials ore at the mixing ratio shown in Table 2, the mixture was mixed and stirred using a drum mixer. (Treatment: 5-7 kg / batch, drum rotation speed: 37 rpm, residence time: 8 minutes )

(2) No. 2: Mixing and stirring was carried out in the same manner as in No. 2, except that the compounding amount of maramamba ore (ore W) was 20% by mass (reduced compounding amount of this ore H).

(3) No.3: After high speed stirring mixing treatment of maramom bar ore (ore W) (throughput: 3 ~ 5L / batch, fan rotation speed: 47rpm, azi data rotation speed: 891rpm, residence time: 45 seconds), Other ores (ores R, Y, H, C, D) Limestone, quicklime, silica and serpentine were blended and mixed and stirred using a drum mixer (treatment conditions were the same as No. 1).

(4) No. 4: High-speed stirring and mixing treatment (same as treatment condition No. 3) by combining maramamba ore (ore W), ore R and ore Y, and other ores (ores H, C, D), Limestone, quicklime, silica and serpentine were mixed and mixed and stirred with a drum mixer (treatment conditions were the same as in No. 1).

On the other hand, 7.0% by mass was added to all the raw materials by the drum mixer for the water addition, No.1 and No.2, and 8.0% by mass for the high speed stirring mixed raw materials for the Nos. 3 and No.4, and other raw materials. 7.0 mass% was added with the drum mixer. In addition, as a high speed stirring mixer, an Iritrich mixer incorporating a high-speed rotating blade (agitator) was used.

Table 1

TABLE 2

About each said sintered raw material, it filled in the sintering pan test apparatus (atmospheric suction, suction pressure: 3.53 kPa), and measured the packed-bed breathability index (JPU) immediately after dismounting. On the other hand, the packed bed breathability index JPU is a value obtained according to the following (2), and the higher this value, the better the breathability.

JPU = F / A × (h / s) ^0.6 ‥‥‥‥‥‥‥ (2)

F: Gas flow rate (Nm ³ / min)

A: suction area (m ² )

h: suction layer thickness (m)

s: suction fitting (mH ₂ O)

The measurement results of the filling air permeability index (JPU) are shown in FIG. 1. In the case of mixing and stirring a blended material containing 20 mass% of maramamba ore (ore W) with a drum mixer (No. 2), the cold breathability index was extremely decreased. It can be seen that. On the other hand, in the case where maramamba ore (ore W) was mixed in high speed in advance (No. 3), and the maramamba ore (ore W) and ore R and Y were mixed in high speed in advance (No. 4), the packed bed It can be seen that the breathability index (JPU) has been improved. In particular, it can be seen that No. 4 exhibits better air permeability than a mixture containing no maramamba ore.

For each sintered raw material, the time until the completion of sintering (sintering time) was compared and shown in FIG. 2. In addition, "sintering time" is the time which judged completion | finish of sintering on the basis of the time by which exhaust gas temperature during baking becomes the maximum. In addition, based on the "sintering time", the results of evaluating the production rate per unit firing area of the product of 5mm or more is shown in FIG.

As can be clearly seen from these results, when using mara mamba ore as a raw material, the ore is mixed in advance by high-speed stirring and mixed with other ores as a sintering raw material, or after mixing with other ores and high-speed stirring By mixing with other ores to form a sintered raw material, it can be seen that productivity can be improved by improving the assemblability of the maramamba ore having poor granularity.

Example 1-2

Next, the influence of the specific surface area of the ore to be blended was investigated. Using each raw material ore D, C, H, R, and Y having the chemical composition shown in Table 1 above, these were combined so as to be 25 parts by mass with respect to 100 parts by mass of the maramom bar ore (the ore W), and a high speed stirring mixture was performed. Treatment (treatment conditions were the same as in Example 1). The specific surface area according to the adsorption method of each raw material D, C, H, R, Y at this time is shown in Table 3.

TABLE 3

With respect to the high speed stirring raw material, the various ores, limestone, quicklime, quartzite and serpentine are mixed so that the ratio of the high speed stirring mixed raw material is 20% by mass at various mixing ratios shown in the following Table 4 (thus shown in the following Table 4). The total amount of the raw materials was 80% by mass. The mixing and stirring (treatment conditions were the same as those in Example 1-1) using a drum mixer.

For the water addition, 9.0% by mass of the high speed stirring treatment raw material and 7.0% by mass of the other raw materials were added by a drum mixer.

Table 4

Each of the sintered raw materials was filled in a sintering pan test apparatus (atmospheric suction, suction pressure: 3.53 kPa), and immediately after ignition, the cold breathability index JPU was measured as in Example 1-1.

The relationship between the specific surface area of each ore blended and the packed bed breathability index JPU is shown in FIG. 4, and the relationship between the specific surface area and the firing time is shown in FIG. 5, and the relationship between the specific surface area and the productivity is shown in FIG. 6, respectively. As can be seen from these results, it can be seen that the air permeability of the sintered raw material can be improved and productivity can be improved by setting the specific surface area of the ore to be blended into the maramom bar ore to be 3 m 2 / g or more.

Example 1-3

Next, the influence of the particle size composition of the ore to be blended was investigated.

The raw material ore H shown in Table 1 above was blended in an amount of 50 parts by mass with respect to 150 parts by mass of the maramamba ore (the ore W), and subjected to a high speed stirring mixing treatment (treatment conditions are the same as those in Example 1-1). The granularity of the raw material ore H at this time was adjusted by mixing a predetermined amount of the ore H obtained by sieving each particle size. The granularity of the nuclear ore H provided for the test is shown in Table 5 below. At this time, the raw material (No. 10) which did not mix | blend ore H was also prepared.

Table 5

15 mass% (No. 10) or 20 mass% of the ore, limestone, quicklime, quartzite, serpentine is 15 mass% (No. 10) or 20 mass% with respect to the said high speed stirring mixing raw material at the various mixing ratios shown in Table 6 below. (No. 11 to No. 19), and (therefore, the sum of the raw materials shown in the following Table 6 is 80% by mass or 85% by mass). Mixing and stirring using a drum mixer (processing conditions are shown in Example 1-1 Equal to).

For the water addition, 9.0% by mass of the high speed stirring treatment raw material and 7.0% by mass of the other raw materials were added in a drum mixer.

Table 6

For each of the above sintered raw materials, the sintering fan test apparatus (atmospheric suction, suction input: 3.53 kPa) was filled and fired, and the particle ratio of the mixed ore particles having a particle size of 3 mm or more and less than 5 mm and a particle ratio of 5 mm or more and less than 10 mm were fired. And its effect on production rates.

The influence of the particle ratio of 3 mm or more and less than 5 mm on the baking time in FIG. 7 and the effect on productivity are shown in FIG. 8, respectively. In addition, Fig. 9 shows the effect of the particle ratio of 5 mm or more and less than 10 mm on the firing time, and Fig. 10 shows the effect on the production rate. In addition, the influence on the sintering time and the production rate was hardly recognized for the particle ratio whose particle diameter is 1 mm or more and less than 3 mm.

As can be seen from these results, it is understood that the granulation property is increased and the production rate is improved by blending the nucleus particles having predetermined granularity. In addition, according to the result of FIG. 7 and FIG. 9, the relationship of said Formula (1) (collective correlation formula) is calculated | required. That is, equation (1) is obtained by focusing only on the firing time. In Equation (1), 14.5 on the right side is a firing time when the same raw material as used in Figs. 7 and 9 is granulated by a conventional drum mixer.

In addition, in FIGS. 7-10, the data in the case of 100% of the particle | grains in the particle size range which focused on each is also attached for reference. The reason why the data of 100% in Figs. 7 and 9 is not on the straight line based on the data of the low% is considered to be as follows. In FIG. 7, not only does it increase by the amount of particles (= decrease in fine amount), but also exists as a nucleus of a granulated material, and when it exists as particle | grains alone, the packing density of a packed layer raises and air permeability is impaired, and baking time Is assumed to be long. In the case of FIG. 9, when the particle amount increases, the packing density of the packed layer decreases, so that the air permeability is improved, and as a result, the firing time is shortened. In obtaining the formula (1), since only the data of the practical area (data of Figs. 7 and 9 except 100% of data) are used, it is not necessary to consider the reason why they do not lie on the straight line.

Example 2

Next, the Example concerning this 2nd invention is described below.

Example 2-1

Using West Australia's West Angelaz ore (Wara abbreviation) from Australia as the maramamba ore and Hamastre ore (HO or abbreviation) from the same Australia as hematite ore, WA is made 20% by mass (constant) of new raw materials and HO is newly added. It was made to mix | blend and mix into 0-15 mass% range in a raw material. Raw materials other than WA and HO in new raw materials are 21.7 mass% of cala Jasmine, 6.0 mass% of lyodocerite, 6.0 mass% of lobrio ore, 0.9 mass% of silica, 12.9 mass% of limestone, 2.0 mass% of quicklime, and serpentine 0.7 It was set as the compounding ratio fixed in mass%, respectively. And 20 mass% of semi-gloss and 5.3 mass% of powdered coke were mix | blended in the external ratio with respect to new raw material.

Table 7 shows the crystal water content, the SiO ₂ content, and the particle size distribution of WA and HO.

TABLE 7

In Table 8, the mixing ratio of WA and HO of the comparative example and the example of the present invention and the ratio of ˜0.5 mm of the fine powder before the WA + HO mixture assembly are shown.

Table 8

WA and HO were blended in the blending ratios shown in Table 8, 8 mass% of water was added at an external ratio to the total amount of WA + HO, and mixed granulation was performed by a high speed stirring mixer. In addition, as a high speed stirring mixer, an Irithi mixer (a throughput: 3-5 L / batch, a fan rotation speed: 47 rpm, an agitator rotation speed: 891 rpm, a residence time: 45 seconds) in which a high speed stirring blade (agitator) is built in Was used.

After mixing and assembling the water added to WA + HO with an Eirich mixer, the remaining compounding ingredients (other new raw materials, semi-gloss, powdered coke) are added, and at a water content of 7.0% by mass at an external ratio with respect to the entire blended raw materials. Moisture was added as much as possible, and mixed and granulated in a drum mixer (throughput: 5-7 Kg / batch, drum rotation speed: 37 rpm, residence time 8 minutes) to obtain a sintered raw material.

This sintered raw material was filled in the sintering pan test apparatus (atmospheric suction, suction pressure: 2.94 Kpa), and the cold breathability index JPU immediately after ignition was measured. The measurement results are shown in FIG. 11. As shown in FIG. 11, the proportion of ˜0.5 mm of fine powder in the compound (WA + HO) increases beyond 30 mass%, and the JPU tends to decrease, while the JPU rapidly decreases even below 25 mass%. It is admitted. In contrast, when the differential ratio of ˜0.5 mm in the compound (WA + HO) was in the range of 25% by mass or more and less than 30% by mass, the JPU exhibited a high value, and it was found that the breathability in the cold of the packed layer was maintained.

Example 2-2

Next, using the sintered raw material made in Example 2-1, the sintered ore manufacturing experiment was conducted by the sintering pan test apparatus. 12 shows the relationship between the pulverization time and the ratio of the fine powder of ˜0.5 mm in the compound (WA + HO) obtained from the experimental results. As shown in FIG. 12, it can be seen that the ratio of the fine powder of ˜0.5 mm in the compound (WA + HO) decreases and the firing time is appropriately shortened.

When the result of the said Example 2-1, 2-2 is judged comprehensively, if the ratio of the ~ 0.5mm fine powder in a compound (WA + HO) is made into the range of 25 mass% or more and less than 30 mass%, it will be cold of a packed layer. By maintaining the air permeability, it is possible to be uniformly fired in the horizontal cross-sectional direction, thereby ensuring a high product recovery rate and reducing the firing time to a sufficient level, thereby maintaining a high production rate.

In addition, the drop strength of the sinter cake (Sinter cake) manufactured by the sintering pan test apparatus was measured, and the present invention is applied to a batch mixture of a good blended raw material using no conventional maramamba ore at once. It was found that roughly the same drop strength can be obtained compared to the above, and the product recovery rate level can be maintained at about the same level as the conventional one.

Claims (5)

Particles having a specific surface area of 3 m ² / g or more and a particle diameter of 3 mm or more and less than 5 mm in a maramamba ore containing 3.0 mass% or more of crystal water, 4.0 mass% or less of SiO ₂ , and 20 mass% or more of fine powder having a particle diameter of 0.25 mm or less. The relationship between the ratio A ₁ (mass%) and the ratio A ₂ (mass%) of the particles having a particle diameter of 5 mm or more and less than 10 mm is a blend containing ores satisfying the following formula (1), and the blend is a predetermined stirring speed. Sintering ore manufacturing method characterized by sintering after mixing and granulation. 13. 2-0.014 x A ₁ + 0.033 x A ₂ <14.5. (One) The method for producing a sintered ore according to claim 1, wherein a compounding amount of the ore to be blended with the maramamba ore is 20 to 60 parts by mass with respect to 100 parts by mass of the maramamba ore. The method for producing a sintered ore according to claim 1, wherein the water content in the blend is 5 to 10% by mass. Determining the number of 3.0 mass% or more, SiO ₂ 4.0% by mass or less, the fine powder of less than 0.25mm to Mara mamba ore containing 20 mass% or more, the number of decision 2.0 to 4.0 mass%, SiO ₂ 3.0% by mass or more, A hematite ore containing 0.25 mm or less of powder at less than 20% by mass is added to prepare a compound in which SiO ₂ is 3.0 to 5.0% by mass and 0.5 mm or less is at least 25% by mass and less than 30% by mass. The method for producing a sintered ore characterized by sintering after mixing and assembling at a predetermined stirring speed or higher. The method for producing a sintered ore according to claim 4, wherein the water content of the blend is 5 to 10% by mass.