JP6493305B2 - Method for producing sintered ore - Google Patents

Description

  The present invention relates to a method for producing sintered ore of a blast furnace raw material used in a Dwight-Lloyd type sintering machine or the like.

  Sintered ore consists of several brands of fine iron ore (generally called sinter feed of about 125 to 1000 μm), auxiliary raw material powders such as limestone, quartzite, and serpentine, and dust, scale, return ore, etc. Sintered blended raw material (hereinafter sometimes referred to as “raw material”) in which an appropriate amount of various raw material powders and solid fuel such as powdered coke are blended in an appropriate amount, and water are mixed and granulated. It is manufactured by charging the particles into a sintering machine and firing them. Since the raw materials contain moisture, they aggregate together to become pseudo particles during granulation. Then, when the pseudo-particulated raw material is charged on the pallet of the sintering machine, it helps to ensure good ventilation of the raw material charging layer, and smoothly advances the sintering reaction.

  In recent years, pulverization of iron ore has progressed, and when granulated particles contain fine ore, the strength of the granulated particles decreases. In particular, when water is added, the strength of the granulated particles is greatly reduced, and the granulated particles are disintegrated and pulverized at the time of charging on the pallet or firing to deteriorate the air permeability of the raw material charging layer. It is also known that the fine ore is difficult to granulate. In such an environment surrounding sintered iron ore for sintering, a technique for producing high-quality sintered ore using iron ore containing a large amount of fine particles that are difficult to granulate has recently been disclosed in Patent Document 1. Proposed in ~ 6. These techniques relate to a process of crushing and granulating a raw material containing fine ore with high adhesion and easily agglomerating with a stirrer before granulating with a granulator.

Japanese Patent Laid-Open No. 11-61282 JP-A-7-331342 JP 7-48634 A JP 2005-194616 A JP 2006-63350 A JP 2007-247020 A

  As described above, granulated particles containing only fine powder have lower strength than granulated particles containing nuclear ore. For this reason, if granulated particles having low strength are present in the raw material, the granulated particles are softened or disintegrated and powdered when charged into the sintered pallet or when fired, and the air permeability of the raw material charged layer is deteriorated. In addition, the presence of granulated particles of only fine powder causes a problem that powder coke, which is a coagulant, enters inside the granulated particles and makes it difficult for the raw material to burn. For this reason, there exists a request | requirement of suppressing the granulation particle | grains of only a fine powder being granulated.

  In the granulation step, it is effective to previously pulverize and disintegrate the fine powder aggregates contained in the raw material in order to suppress the granulation of the granulated particles containing only the fine powder. For this reason, before the granulation step, the raw material is pre-treated using a stirrer, and the fine powder aggregates contained in the raw material before granulation are pulverized and crushed, so that the fine powder in the next granulation step Granulation of only granulated particles can be suppressed. However, conventionally, when pre-processing conditions of the stirring device are determined, the raw materials are actually pre-processed with various conditions with a stirrer, and the sinterability of each raw material after the pre-processing is evaluated, based on the results. Pre-processing conditions were defined. For this reason, the big load has arisen in defining the pre-processing conditions of a stirring apparatus. An object of the present invention is to provide a method for producing a sintered ore that can determine the pretreatment conditions of the raw material without actually performing the pretreatment using a stirring device by measuring the properties and the like of the raw material. .

The features of the present invention for solving such problems are as follows.
[1] In a method for producing a sintered ore in which a pretreatment of a sintered raw material is performed with a stirrer, a minimum value of a weighted average particle size of the sintered raw material targeted after the pretreatment is determined, and the stirrer The pre-treatment is performed so that the sintered raw material to be charged satisfies the following mathematical formula (1).
J × ( 1−Σ [0.5 × x (i) × f (i) × G × {P (i) / S (i)} ^H ] / d ₀ ) + L <D _T / d _0. Formula (1)
However, in the above mathematical formula (1), d ₀ represents the weighted average particle diameter of the sintered raw material before the pretreatment, x (i) represents the respective particle diameter of the sintered raw material, and f (I) represents the mass ratio of the particle diameter x (i), P (i) represents the impact force exerted on the particles having the particle diameter x (i) by the stirring blade of the stirring device, and S (i) is , Represents the particle strength of the particle diameter x (i), G, H, J, L represent constants, _DT represents the minimum of the weighted average particle diameter of the target sintered raw material after the pretreatment Represents a value.
[2] The method for producing a sintered ore according to (1), wherein _DT is 3 mm or less in the mathematical formula (1).

  By substituting the minimum value of the weighted average particle size of the target raw material after pre-treatment into the mathematical formula (1), pre-treatment suitable for the subsequent sintering process without actually pre-treatment using the stirring device Conditions can be defined. Thus, by implementing the manufacturing method of the sintered ore of this invention, the pre-processing conditions of a raw material can be optimized easily.

3 is an internal perspective view of the stirring device 10. FIG. It is the top view which looked at FIG. 1 from the top. 1-sigma is a graph showing the relationship between {0.5 × x (i) × f (i) × S Di} / d 0 and _{D min} / _{d 0.} It is a graph which shows the relationship between P (i) / S (i) and _SDi . It is a graph which shows the relationship between the minimum value ( _Dmin ) of the average particle diameter after a stirring process, and a sintering production rate.

  Hereinafter, the present invention will be described through embodiments of the invention. FIG. 1 is an internal perspective view of the stirring device 10. FIG. 2 is a plan view of FIG. 1 viewed from above. First, the structure of the stirring apparatus 10 which is an example of the stirring apparatus which can be used for the manufacturing method of the sintered ore of this embodiment is demonstrated using FIG. 1 and FIG.

  The stirring device 10 is a device that stirs the sintered raw material 12 as a pretreatment. The stirring device 10 includes a cylindrical container 14 in which the sintered raw material 12 is charged, a stirring blade 16, and a weir 18. The cylindrical container 14 includes a cylindrical cylinder 20 and a circular bottom plate 22. The cylindrical container 14 is provided with an opening (not shown) for supplying and discharging the sintered raw material 12. The bottom plate 22 is configured integrally with the cylinder 20, and the bottom plate 22 rotates with the cylinder 20 by receiving a driving force.

  In the present embodiment, the sintered raw material 12 includes fine iron ore, limestone, and solid fuel such as fine powder coke, and further, secondary raw material powder such as silica and serpentine, dust, scale, return mineral, and the like. The miscellaneous raw material powder and a binder may be included.

  The stirring blade 16 includes a rotating shaft 24 and a plurality of stirring plates 26. The stirring blade 16 is provided at a position eccentric from the center of the cylindrical container 14. The rotating shaft 24 rotates by receiving a driving force from a driving unit (not shown) provided on the upper side of the cylindrical container 14. For this reason, the stirring blade 16 and the bottom plate 22 can rotate independently of each other. The stirring blade 16 may be provided at the center of the cylindrical container 14.

  The stirring plate 26 is provided to project radially outward from the rotating shaft 24. In the example shown in FIGS. 1 and 2, the stirring plate 26 is provided in six directions at 60 ° intervals at two locations in the vertical direction of the rotating shaft 24. Therefore, the stirring blade 16 is provided with a total of 12 stirring plates 26.

  Next, operation | movement of the stirring apparatus 10 is demonstrated. In a state where the sintering raw material 12 is charged in the cylindrical container 14, the bottom plate 22 rotates, for example, clockwise, and the stirring blade 16 rotates counterclockwise. As the bottom plate 22 rotates clockwise, the sintering raw material 12 charged in the cylindrical container 14 rotates clockwise together with the bottom plate 22. The sintered raw material 12 rotated clockwise is collided with the stirring blade 16 rotated counterclockwise, whereby the fine powder aggregates of the sintered raw material 12 are pulverized and crushed.

  By using the stirring device 10 to stir the sintered raw material 12, the fine powder aggregates of the sintered raw material 12 can be crushed and the fine powder can be dispersed in the sintered raw material 12. The sintered raw material 12 stirred by the stirring device 10 is granulated using a granulating device such as a drum mixer and then sintered by a Dwight-Lloyd type sintering machine. In this way, sintered ore is produced from the sintered raw material 12.

Next, the granulation property and pulverization property of the sintered raw material 12 by the stirring process of the stirring device will be described. In order to comprehensively evaluate the granulation performance and crushing performance of the stirrer, the time-dependent changes in the particle size distribution due to the stirring process obtained in the experiment were analyzed using a matrix model. Assume that this experimental system follows a simple Markov process, the particle size distribution before stirring treatment is the vector F _N , the granulation and disintegration probability is θ, the granulation and disintegration matrix is B, the unit vector is E, and the number of stirring steps is N Then, the particle size distribution vector G _N of the sintering material 12 after stirring process is represented by equation (2).

G _N = {(1−θ) × E + θ × B} × F _N Formula (2)

Here, the mass ratio in each sieve section of the sintered raw material 12 after the stirring treatment is defined as g ₁ , g ₂ ... _Gn from the fine grain side, and in each sieve section of the sintered raw material 12 before the stirring treatment. When the mass ratio to _{f 1, f} 2 ··· _{f n} from the fine particle side, _{G n} vectors following equation (3) and equation (4), _{F n} vector by the following equation (5) and equation (6) expressed.

  Moreover, the granulation matrix B is represented by the following numerical formula (7) and numerical formula (8).

Here, q _ij is 0 or a positive number. Matrix B, as shown in the following equation (9), is expressed by the sum of _{B G} matrix and _{B D} matrix. Here, each coefficient of the _BG matrix indicates the residual to the same particle size and the degree of migration of the adhering powder from the fine particle component (granulation factor), and each coefficient of the _BD matrix indicates the residual to the same particle size. And the transition degree (disintegration factor) of the disintegrated powder from the coarse-grained component is shown. Here, it is assumed that the residual probabilities for the same granularity are equal, and B _G and B _D are equally distributed, and the coefficient of the diagonal component is 0.5. The _BG matrix is shown in the following formula (10), and the _BD matrix is shown in the following formula (11).

B = B _G + B _D (9)

The average particle diameter of the larger the value of each element of the granulated components B _G increases. Moreover, the component of the same line represents the inflow probability of the decay | disintegrating powder and adhesion powder to the target particle size area | region, and means that the convergence degree to the particle size is so large that the sum of a line component is large. Moreover, the component of the same row | line has shown the probability that the target particle size will transfer to another particle size, and, thereby, the priority of granulation and disintegration can be evaluated.

Next, the relationship between each parameter and the properties of the sintered raw material 12 will be considered. The granulation matrix B, which is a matrix element, is the sum of the collapse matrix B _D and the granulation matrix B _G. The granulation granularity S _Gj (unit: −) is defined as the following formula (12) for the column element j of the target granularity region.

From Equation (8), the degree of decay S _Dj (unit: −) is expressed by Equation (13) below.

S _Dj = 1−S _Gj ... (13)

The granulation particle size S _Gj represents the rate at which the target particle size shifts to a larger particle size range, and the disintegration degree S _Dj represents the rate at which the particle size shifts to a smaller particle size range. That is, if _SDj is larger than 0.5, it means that disintegration proceeds with priority, and if it is less than 0.5, it means that granulation proceeds preferentially.

  Next, the impact force exerted on the fine powder aggregate by the stirring blade 16 of the stirring device 10 will be described. Since the impact force is affected by the particle radius and particle mass of the sintered raw material 12, it is calculated for each particle diameter x (i) of the sintered raw material 12 in this embodiment. In the present embodiment, the particle diameter x (i) is, for example, a weighted average value of each sieve when the sintered raw material 12 is sieved using a plurality of sieves having different sieves. The impact force P (i) (unit: Pa) exerted on the particles having the particle diameter x (i) by the stirring blade 16 is based on the conventional model and the fine powder aggregates of the sintered raw material 12 and the properties of the stirring blade 16. And can be calculated using the following mathematical formula (14).

In the above mathematical formula (14), π represents the circularity ratio, r represents the particle radius (unit: m) of the particle diameter x (i), and M represents the particle mass of the particle having the particle diameter x (i) ( (Unit: kg), and V ₀ represents the peripheral speed (unit: m / s) of the stirring plate 26. V ₀ can be calculated by the following formula (15), and K can be calculated by the following formula (16).

  In the above mathematical formula (15), π represents the circular ratio, R represents the radius (unit: m) of the stirring blade 16, and N represents the rotational speed (unit: rpm) of the stirring blade 16.

In the above formula (16), r represents the particle radius (m), ν _S represents the Poisson ratio (unit: −) of the particle, and ν _W represents the Poisson ratio (unit: −) of the stirring plate 26. E _S represents the Young's modulus (unit: Pa) of the particles, and E _W represents the Young's modulus (unit: Pa) of the stirring plate 26. In the present embodiment, the Young's modulus E _S of the fine aggregate of the sintering material 12 was measured using a crushing strength measuring apparatus equipped with a load cell. Further, the Poisson's ratio ν _S of the fine powder aggregate of the sintering raw material 12 was calculated by measuring the longitudinal displacement and the lateral displacement when measuring the crushing strength of the fine powder aggregate. Furthermore, the Young's modulus _{E W} and Poisson's ratio _{E W} of the stirring plate 26, using the value of ordinary steel, the Young's modulus _{E W} and 210 GPa, and Poisson's ratio [nu _W of 0.3.

  Next, the particle strength of the sintered raw material 12 will be described. Assuming that the particles of the fine powder aggregate in the sintered raw material 12 are spheres having a radius r, the particle strength S (i) (unit: MPa) can be calculated using the following formula (17). In the sintered raw material 12, since the fine powder aggregates are aggregated by moisture, the particles are wet particles containing moisture.

  In the above mathematical formula (17), π represents the circumference, r represents the particle radius (unit: m), and P represents the crushing strength of the particle (unit: kgf / piece). The crushing strength is measured using, for example, a compressive strength measuring device provided with a load cell and a displacement meter that measures the position of the load cell.

The fine powder aggregates in the sintering raw material 12 may be of an ideal two-layer structure of core powder, or may exist as a single particle without taking its form. In order to strictly discuss the disintegration process of such fine powder aggregates, the strength in all transition periods, that is, the strength before the stirring treatment and the strength of the fine powder aggregate during the stirring treatment should be measured. However, it is difficult to measure the strength of these fine powder aggregates. For this reason, after crushing the sintered raw material 12 using a granulator such as a drum mixer, the crushing strength of the particles in a state where the particle size of the sintered raw material 12 is stable was measured. high correlation to the _min / _{d 0} has been confirmed. From this, it was found that the crushing strength of the particles after granulation using the granulator may be regarded as the crushing strength before the stirring treatment and the crushing strength during the stirring treatment.

In this embodiment, in order to directly show the relationship between the weighted average particle diameter and the degree of disintegration, the inventors have expressed the mass ratio of the particle diameter x (i) and the particle diameter x (i), f (i ) (Unit: −), disintegration degree S _Di, and average particle diameter d ₀ (unit: mm) of the sintered raw material 12 before the stirring treatment, It was defined as the granulation index of particles. In the present embodiment, the average particle diameter means a weighted average particle diameter unless there is a description that the particle diameter is other than that.

Granulation index = 1-Σ [0.5 × x (i) × f (i) × S _Di ] / d ₀ Formula (18)

The granulation index represented by the mathematical formula (18) represents the particle size after the particles of the mass ratio f (i) having the particle size x (i) are crushed and disintegrated by the stirring process of the stirring device 10. By integrating this, the weighted average particle diameter of the sintered raw material 12 after being crushed and disintegrated by the stirring process of the stirring device 10 is calculated. In addition, 0.5 in Formula (18) is multiplied by 0.5 assuming that the particle diameter is halved with the collapse. The dimensionless number obtained by dividing this value by the weighted average particle diameter d ₀ before the stirring treatment is the disintegration index, and the weighted average particle size of the sintered raw material 12 before the stirring treatment is crushed by the stirring treatment of the stirring device 10. It shows how much it has collapsed and becomes smaller. And the granulation property index is calculated by subtracting the disintegration index from 1.

When the sintering raw material 12 is stirred using the stirring device 10, the average particle diameter of the sintering raw material 12 decreases, and then becomes substantially constant or increases. Minimum value _{D min} (unit: mm) of the average particle size and then, a value obtained by dividing the _{D min} in average particle size _{d 0} of the stirring process before sintering material 12 and _{D min} / _{d 0.} As a result of experiments described later, the correlation between the granulation index shown in Formula (18) and D _min / d ₀ was confirmed. As the granulation index increased, D _min / d ₀ also increased, and the granulation index increased. And a high correlation between D _min / d ₀ was confirmed. Thereby, the following numerical formula (19) can be derived.

1−Σ {0.5 × x (i) × f (i) × S _Di } / d ₀ = D _min / d ₀ (Equation 19)

By using Formula (19), it is possible to grasp the x (i), f (i) and S _Di of the sintering raw material in advance without actually performing the stirring process using the stirring device 10. D _min that is the minimum value of the average particle diameter of the sintered raw material 12 after the stirring treatment can be calculated. Moreover, when the minimum value of the average particle diameter of the sintering raw material 12 after the target stirring process is determined, the sintering raw material that can be set to the target value without performing the stirring process using the stirring device 10 Twelve stirring conditions can be easily determined.

Furthermore, the inventors have found that there is a correlation between the disintegration degree S _Di and P (i) / S (i), which is the ratio of the impact force P (i) and the particle strength S (i). . Performed an experiment described _below, to obtain the _{S Di,} a plot showing the relationship between P (i) / S (i ). Then, the following formula (20) can be derived by fitting the plot to a power approximation curve.

1.32 × (1-Σ [0.30 × x (i) × f (i) × {P (i) / S (i)} ^0.14 ] / d ₀ ) −0.23 = D _min / d ₀ Formula (20)

In this result, the result of the above formula (20) was obtained. For example, the relationship between the disintegration degree S _Di and P (i) / S (i) depends on the configuration of the stirring device 10 used. Since it can change, the following formula (21) can be derived by generalizing the formula (20) using the constants G, H, J, and L.

J × (1−Σ [0.5 × x (i) × f (i) × G × {P (i) / S (i)} ^H ] / d ₀ ) + L = D _min / d _0. Formula (21)

When the minimum value of the average particle diameter of the sintered raw material 12 after the stirring treatment is reduced, the production rate of the sintered ore is maintained and improved. For this reason, when the minimum value of the average particle diameter of the target sintering raw material 12 is defined as _DT , the stirring condition of the stirring device 10 is determined so as to satisfy the following formula (1). Thereby, the minimum value of the average particle diameter of the sintered raw material 12 after the stirring treatment can be made smaller than _DT .

J × (1-Σ [0.5 × x (i) × f (i) × G × {P (i) / S (i)} ^H ] / d ₀ ) + L <D _T / d _0. Formula (1)

  Thus, by carrying out the method for producing sintered ore according to the present embodiment, the stirring device 10 is stirred so that the average particle size becomes smaller than the minimum value of the average particle size of the sintered raw material 12 as the target value. Conditions can be defined. Thereby, actually, stirring conditions suitable for the subsequent sintering process can be easily determined without stirring the sintered raw material 12 using the stirring device 10. And by the said stirring conditions, the minimum value of the average particle diameter of the sintering raw material 12 after a stirring process can be made small, and, thereby, the productivity of sintered ore can be maintained and improved.

  In addition, when the relationship between the minimum value of the average particle size of the sintered raw material 12 and the production rate of the sintered ore was confirmed, in order to maintain and improve the production rate of the sintered ore, It was found that the minimum value of the particle size is preferably 3 mm or less. Thus, in this embodiment, it is preferable to determine the stirring conditions of the stirring apparatus 10 so that the minimum value of the average particle diameter of the target sintering raw material 12 is 3 mm or less. Thereby, productivity of the sintered ore of the sintering raw material 12 which performed the said stirring process can be maintained and improved.

Next, an experiment in which the correlation between 1−Σ {0.5 × x (i) × f (i) × S _Di } / d ₀ and D _min / d ₀ shown in Expression (19) is confirmed will be described. To do. In this experiment, a sample in which the raw materials shown in Table 1 below were blended at T1 to T3 shown in Table 2 and the moisture ratio was adjusted to 5.2 mass% was used. In addition, the value of T1-T3 shown in Table 2 is the mass% ratio of each dried raw material. Moreover, the moisture ratio of the sample was calculated by water mass / (dry raw material mass + water mass).

  In this experiment, samples T1 to T3 were put into the stirring device 10, and after stirring processing was performed under the conditions (60 to 1000 rpm) with the rotation speed of the stirring blade 16 changed, the sample in the device was sampled. In addition, for T1, experiments were also performed in the case where the moisture ratio was 3.5 and 7.5% by mass. The sampling method assumes a continuous operation in which the sintering raw material 12 is continuously discharged from the discharge port installed at the bottom of the stirring device 10 and is about 1 kg from the surface of the sintering raw material 12 staying in the vicinity of the discharge port. Collected.

  The sample after collection was sieved in a wet state, and the particle size distribution and moisture for each particle size were measured. The meshes used were 11.2 mm, 9.52 mm, 8.0 mm, 4.75 mm, 2.8 mm, 1.0 mm, and 0.5 mm. There are no particles larger than the mesh size of 11.2 mm, and the arithmetic average value of the aperture diameter is used as the representative particle size, and 10.4 mm, 8.8 mm, 6.4 mm, 3.8 mm, 1.9 mm, They were 0.75 mm and 0.25 mm. A weighted average of these representative particle sizes and the mass ratio of each particle size was defined as the average particle size. A value obtained by dividing the mass difference before and after drying by the total moisture mass (total particle size) before drying was defined as the moisture ratio.

FIG. 3 is a graph showing the relationship between 1−Σ {0.5 × x (i) × f (i) × S _Di } / d ₀ and D _min / d ₀ . The horizontal axis of the graph shown in FIG. 3 is 1−Σ {0.5 × x (i) × f (i) × S _Di } / d ₀ . The horizontal axis represents the product of particle size x (i), initial mass ratio f (i) and disintegration degree S _Di over all particle sizes, and this integrated value was divided by the average particle size d ₀ before the stirring treatment. Value. S _Di is calculated using particles having a particle size of 3.8 mm or more, using the average particle size of the sintered raw material 12 before the stirring treatment and the average particle size of the sintered raw material 12 after the stirring treatment. did. The vertical axis is a value obtained by dividing the average particle diameter d ₀ of the pre-stirring treatment of D _min is the minimum value of the average particle size after stirring treatment of the sintered material 12.

As shown in FIG. 3, when 1−Σ {0.5 × x (i) × f (i) × S _Di } / d ₀ increases, D _min / d ₀ tends to increase. Has found a certain relationship.

FIG. 4 is a graph showing the relationship between P (i) / S (i) and S _Di. The horizontal axis of the graph shown in FIG. 4 is P (i), which is the impact force exerted on the particles having the particle diameter x (i) by the stirring blade 16 of the stirring device 10, and S (i), which is the particle strength of T1 to T3. ). The vertical axis represents the degree of decay S _Di. As shown in FIG. 4, there is a certain relationship between P (i) / S (i) (unit: −), which is the ratio of impact force to particle strength, and the degree of disintegration S _Di (unit: −). I found out. As a result of fitting the plot shown in FIG. 4 to a power approximation curve, the following formula (20) was derived.

1.32 × (1-Σ [0.30 × x (i) × f (i) × {P (i) / S (i)} ^0.14 ] / d ₀ ) −0.23 = D _min / d ₀ Formula (20)

  In the stirring device 10 and the stirring conditions used in this experiment, the relationship shown in the above formula (20) was derived. However, the relationship shown in FIGS. 3 and 4 varies depending on the configuration of the stirring device 10 and the stirring conditions. obtain. For this reason, the following numerical formula (21) which generalized numerical formula (20) can be derived. In addition, in the case shown in Formula (21), the values shown in Table 3 below are used for the values of G, H, J, and L.

J × ( 1−Σ [0.5 × x (i) × f (i) × G × {P (i) / S (i)} ^H ] / d ₀ ) + L = D _min / d _0. Formula (21)

  Next, an experiment that confirms the relationship between the minimum value of the average particle diameter of the sintered raw material 12 after the stirring treatment and the production rate of the sintered ore will be described. In Experimental Examples 1 to 4 and Comparative Experimental Examples 1 and 2, each sample shown in Table 4 was stirred under the stirring conditions shown in Table 4.

The sample in the stirring apparatus 10 after the stirring treatment was sampled, and the minimum value of the average particle diameter of the sampled samples was measured. Moreover, this sample was granulated for 5 minutes using a drum mixer, and then baked using a pan tester. The sintered sinter cake is dropped once from a height of 2 m, and a product maintaining a particle size of 10 mm or more is made into a product, and the product quality is divided by the firing time and the cross-sectional area of the test pan to obtain a sintered production rate [t / (H × m ² )] was calculated.

FIG. 5 is a graph showing the relationship between the minimum value (D _min ) of the average particle diameter after the stirring treatment and the sintering production rate. As shown in FIG. 5, compared with the case where the minimum value of the average particle diameter after the stirring treatment is larger than 3 mm, the minimum value of the average particle diameter after the stirring treatment is set to 3 mm or less, thereby reducing the sintering production rate. It can be seen that it can be improved. In addition, reducing the minimum value of the average particle diameter after the stirring treatment means that the fine powder aggregate in which the fine powder in the sintering raw material 12 is aggregated is pulverized and crushed. From FIG. 5, by determining the stirring condition of the stirring device 10 that makes the minimum value of the average particle diameter of the sintered raw material 12 after the stirring treatment 3 mm or less using the above formula (1), sintering of the sintered ore is performed. It can be seen that the production rate can be maintained and improved.

  As described above, by substituting the minimum value of the average particle diameter of the sintered raw material after the target stirring treatment into the mathematical formula (1), the subsequent sintering can be performed without actually using the stirring device. Stirring conditions suitable for the process can be determined. Thereby, the stirring conditions of the sintering raw material 12 can be easily optimized. In addition, the minimum value of the average particle diameter of the sintered raw material after the target stirring treatment is set to 3 mm or less, and the stirring condition of the sintered raw material is determined using the above formula (1). The rate can be maintained and improved. Further, the minimum value of the average particle diameter of the sintered raw material 12 is preferably small. However, in order to reduce the minimum value of the average particle diameter after the stirring treatment, the sintered raw material 12 having a small average particle diameter before the stirring treatment is used. It is necessary to use or improve the stirring ability of the stirring device 10. Moreover, as shown in FIG. 5, even if the minimum value of the average particle size is made smaller than 2 mm, the sintered production rate of the sintered ore is hardly improved. Therefore, even if the minimum value of the average particle size is made smaller than 1 mm, It is predicted that the sintering production rate will not improve. For this reason, it is preferable that the minimum value of the average particle diameter of the sintered raw material after the stirring treatment is 1 mm or more.

  In addition, in this embodiment, although the stirring apparatus 10 showed the example which provided the weir 18, it is not restricted to this. The weir 18 is preferably provided for scraping the sintered raw material 12, but may not be provided. Furthermore, in this embodiment, although the example in which the upper side of the cylindrical container 14 was opened was shown, it is not restricted to this, You may provide the top plate which seals the upper side of the cylindrical container 14. FIG.

  In the present embodiment, the example in which the number of the stirring plates 26 of the stirring device 10 is 12 has been shown, but the present invention is not limited to this, and the shape of the stirring plate 26, the rotational speed of the stirring blade 16, the rotational speed of the bottom plate 22, etc. Depending on the, an arbitrary number of stirring plates 26 may be provided. For example, 8 to 16 stirring plates 26 may be provided at 4 to 8 positions in the vertical direction of the rotating shaft 24. Further, the angle of the stirring plate 26 and the interval between the stirring plates 26 may be arbitrarily determined.

  In the present embodiment, the bottom plate 22 and the stirring blade 16 both rotate clockwise. However, the present invention is not limited to this, and may be counterclockwise. Furthermore, although the rotation direction of the baseplate 22 and the rotation direction of the stirring blade 16 showed the same example, it is not restricted to this, You may mutually differ.

  Moreover, in this embodiment, although the stirring apparatus 10 was installed horizontally and the example which stir-processes the sintering raw material 12 was shown, it is not restricted to this, You may use the stirring apparatus 10 inclining. Alternatively, the stirring blade 16 may be supported in the vertical direction, and only the cylindrical container 14 may be tilted. In this way, even if the configuration of the stirring device 10 is changed, by calculating the constants G, H, J, and L of the formula (1) corresponding to the stirring device and the like, similarly, the formula (1) ), The stirring conditions suitable for the subsequent sintering process can be determined without actually stirring using the stirring device.

DESCRIPTION OF SYMBOLS 10 Stirring device 12 Sintering raw material 14 Cylindrical container 16 Stirring blade 18 Weir 20 Cylinder 22 Bottom plate 24 Rotating shaft 26 Stirring plate

Claims (1)

In the manufacturing method of the sintered ore where the pretreatment of the sintering raw material is performed with a stirring device,
Analyzing the change over time in the particle size distribution due to the stirring process of the stirring device using a matrix model, the degree of disintegration S _Di that is the ratio of shifting to a smaller particle size region is obtained,
Determines the minimum value D _T Weighted average particle diameter shall be the target after pre-treatment of the sintered material to 3mm or less, the sintering raw material charged to the stirring device so as to satisfy the following formula (1) The method for producing sintered ore, wherein the pretreatment is performed.
J × (1−Σ [0.5 × x (i) × f (i) × G × {P (i) / S (i)} ^H ] / d ₀ ) + L <D _T / d _0. Formula (1)
However, in the above mathematical formula (1), d ₀ represents the weighted average particle diameter of the sintered raw material before the pretreatment, x (i) represents the respective particle diameter of the sintered raw material, and f (I) represents the mass ratio of the particle diameter x (i), P (i) represents the impact force exerted on the particles having the particle diameter x (i) by the stirring blade of the stirring device, and S (i) is , Represents the particle strength of the particle diameter x (i), and G and H are P (i) / S (i, which is the ratio of the disintegration degree S _Di and the impact force P (i) to the particle strength S (i). ) represents a constant obtained from the correlation with, J, L is, 1-Σ {0.5 × x (i) × f (i) × S Di} / d 0 and correlation of _D min / _{d 0} It represents a constant obtained from.