Granular metal manufacturing device

Abstract

In a granular metal manufacturing device, even if the height is limited, molten metal can be made into granular metal with a specified particle size or less. In a discharge port (4) provided in the bottom (3a) of a container (3), when molten metal flows from an upper first flow path (9) to a lower second flow path (10), the molten metal in the first flow path (9) collides with a step (11) of an inlet of the second flow path (10) formed by a difference in opening area, resulting in a rapid speed change. As a result, a velocity distribution of the flow velocity is generated in the cross-section of the molten metal flowing down from the second flow path (10), and the molten metal that collides with the collision structure (5) and is scattered can be reliably granulated by means of the velocity distribution.

Description

Technical Field

[0001] The present invention relates to a granular metal manufacturing device, and more particularly to a granular metal manufacturing device for manufacturing granular metal by causing molten metal to flow down and collide with a collision structure to granulate, and then solidify the molten metal. Background Art

[0002] As such a granular metal manufacturing device, there is, for example, a device described in the following patent document 1. This granular metal manufacturing device allows molten iron produced by a blast furnace or the like to flow into a container (flow chute), and then allows molten iron of a specified flow rate that overflows from a specified part of the container to flow down by free fall. The flow of the molten iron collides with the inclined surface of the first inclined platform inclined at a specified inclination angle, and a part of it is scattered into the air and granulated. The molten iron that does not scatter but flows down the inclined surface of the first inclined platform collides with the inclined surface of the second inclined platform arranged below the first inclined platform and inclined at a specified inclination angle, and is scattered into the air and granulated. The granulated molten iron falls into the cooling water stored in the water tank below, is cooled and solidified, and is recovered by a conveyor in the form of granular pig iron as granular metal. In addition, it is recorded that more than three inclined platforms can also be provided.

[0003] Prior art literature Patent Literature Patent Document 1: Japanese Patent Application Laid-Open No. 5-154607 Summary of the invention

[0004] Problems to be solved by the invention

[0005] In such granular pig iron manufacturing, as described later, it is important that the molten iron becomes granular pig iron with a particle size below a specified size, and in particular, that the granulated molten iron does not stick together in a state where cooling water is built in. In order to achieve this condition in the granular metal manufacturing device described in Patent Document 1, it is necessary to maintain a relatively high flow rate of the molten iron that collides with the inclined platform, especially the inclined platform of the final stage, so it is necessary to increase the distance in the height direction between the inclined platforms. However, if the distance in the height direction between the inclined platforms is ensured, the problem of the granular metal manufacturing device as a whole becoming larger in the height direction arises. In other words, when the height of the granular metal manufacturing device is limited, it is difficult to make the molten iron (molten metal) become granular pig iron (granular metal) with a particle size below a specified size.

[0006] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a granular metal production apparatus capable of converting molten metal into granular metal having a particle size of less than a predetermined particle size even when the height is restricted.

[0007] Technical solutions to solve problems

[0008] In order to achieve the above object, the present invention provides the following (1) to (6).

[0009] (1) The granular metal manufacturing device of the present invention makes molten metal contained in a container flow down from the container, makes the molten metal collide with a collision structure to granulate, and then solidifies it to manufacture granular metal, wherein a first flow path and a second flow path are arranged in a continuous state at upper and lower positions, the first flow path and the second flow path are used to make the molten metal flow down from the container toward the collision structure, the upper end opening area of ​​the second flow path located at the lower end is smaller than the lower end opening area of ​​the first flow path located at the upper end, and a step is provided between the upper end opening position of the second flow path and the lower end of the first flow path.

[0010] (2) In the granular metal production device according to the present invention, in the granular metal production device according to (1) above, both the first flow path and the second flow path are provided inside the bottom of the container.

[0011] (3) In the granular metal production device according to the present invention, in the granular metal production device according to (1) or (2), the steps are evenly provided around the upper end opening circumference of the second flow path.

[0012] (4) In addition, the granular metal manufacturing device involved in the present invention is a granular metal manufacturing device involved in any one of the above (1) to (3), wherein the hydraulic diameter of the upper end cross-section of the second flow path is 10% to 80% of the hydraulic diameter of the lower end cross-section of the first flow path.

[0013] (5) In the granular metal production device according to the present invention, in any one of (1) to (4), a flow path length of the second flow path is smaller than a flow path length of the first flow path.

[0014] (6) In the granular metal production device according to the present invention, in the granular metal production device according to (5) above, a flow path length of the second flow path is 50% or less of a flow path length of the first flow path.

[0015] Effects of the Invention

[0016] According to the granular metal manufacturing device of the present invention, when molten metal flows from the upper first flow path to the lower second flow path, the molten metal in the first flow path collides with the step at the entrance of the second flow path formed by the difference in opening area, resulting in a rapid velocity change. As a result, a velocity distribution is generated in the cross section of the molten metal flowing down from the second flow path, and the molten metal that collides with the collision structure and flies can be reliably granulated by the velocity distribution. As a result, even when the height of the device is limited, the molten metal can be made into granular metal with a particle size below a specified particle size. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic overall configuration diagram showing one embodiment of the granular metal production apparatus of the present invention. Figure 2 is set at Figure 1 Detail of the iron tapping port at the bottom of the vessel. Figure 3 is from Figure 2 An explanatory diagram of the velocity distribution of the molten metal flowing down the second flow path. Figure 4 is from Figure 2 An explanatory diagram of the effects of molten metal flowing down the first flow path and the second flow path. Figure 5 This is an explanatory diagram of the effect of molten metal flowing down from a conventional flow path. DETAILED DESCRIPTION

[0018] Hereinafter, an embodiment of the granular metal manufacturing device of the present invention will be described in detail with reference to the accompanying drawings. The embodiments shown below illustrate the device and method for realizing the technical idea of ​​the present invention. The technical idea of ​​the present invention does not specify the material, shape, structure, configuration, etc. of the constituent parts to the following embodiments. In addition, the accompanying drawings are schematic. Therefore, it should be noted that the relationship and ratio between the thickness and the plane size are different from the actual ones, and the drawings also include parts with different relationship and ratio of each other's size.

[0019] Figure 1This is a schematic overall structural diagram showing an embodiment of a granular metal manufacturing device. The granular metal manufacturing device of this embodiment manufactures granular pig iron as granular metal from molten iron as molten metal, similarly to the above-mentioned Patent Document 1. Hereinafter, molten iron is treated as molten metal and granular pig iron is treated as granular metal. This granular pig iron manufacturing device is a device for manufacturing granular pig iron with a particle size of about 10 mm in large quantities. For example, molten iron transported by a torpedo tank car 1 flows into a molten iron flow trough 2, and further flows into a receiving container 3 to be temporarily stored. The molten iron contained in the receiving container 3 flows straightly downward from a discharge port 4 provided at the bottom 3a of the receiving container 3 at a predetermined flow rate. The molten iron flowing down from the receiving container 3 falls freely and collides with the upper surface of a collision structure 5 arranged below. Since the upper surface of the collision structure 5 is flat, the molten iron is scattered from the upper surface of the collision structure 5 toward the outer side of the periphery. The molten iron is granulated by the scattering, and then falls into the cooling water in the water tank 6 arranged below.

[0020] The granular molten iron falling into the cooling water is cooled and solidified to become granular pig iron as granular metal. Below the scattering range of the granular molten iron inside the water tank 6, a granular pig iron chute 7 for gathering the solidified granular pig iron is provided. The granular pig iron falling into the chute from the upper end opening of the granular pig iron chute 7 in the water gathers in the central part of the chute along the funnel-shaped inclined surface formed by the conical surface of the truncated cone, and falls into the cooling water again from the lower end opening. Then, the granular pig iron falls in the water onto the upper surface of the mesh belt of the mesh conveyor 8, and is transported to the upper outside of the water tank 6 by the mesh conveyor 8. It should be noted that the cooling water has a higher temperature due to the high-temperature molten iron, so it is configured to introduce low-temperature cooling water. In addition, it can also be configured to cool the cooling water, or both can be used.

[0021] As also described in the above-mentioned Patent Document 1, granular pig iron is easy to use because it is easy to dissolve. Various methods for manufacturing granular pig iron have also been developed, but as described above, a method is becoming popular in which the molten iron flowing down from the receiving container 3 collides with the collision structure 5, granulates it by scattering it into granules, and cools it / solidifies it by falling into the cooling water. On the other hand, the molten iron when falling into the cooling water is at a high temperature of about 1200°C to 1500°C. When such high-temperature (superheated) molten iron comes into contact with water, although the heat of the molten iron is taken away as the water evaporates, it becomes a film boiling state in which its steam film is between the outer surface of the molten iron and the cooling water. In film boiling, evaporation occurs in the steam film by heat transferred from the heating surface through the steam film. The cooling capacity of this film boiling is low, for example, it has a thermal conductivity of only about a few hundredths of that of nucleate boiling in which no steam film is generated. Therefore, when film boiling lasts for a long time, the granulated molten iron may not be sufficiently cooled, resulting in the granulated molten iron sticking together in the cooling water. When the granulated pig iron sticks together (combines), the number of granulated pig iron blocks of a size that is difficult to transport increases, making it difficult to transport. In addition, when cooling water is built into the inside of the combined granulated pig iron, there is a possibility that the cooling water evaporates and causes a water vapor explosion.

[0022] The best way to avoid such a problem is to directly and reliably cool / solidify the granulated molten iron without agglomerating when it falls in the cooling water, and granulate it to a particle size below the specified size. Therefore, in the above-mentioned patent document 1, by setting two or more inclined platforms as the collision structure 5 for the flowing molten iron, the molten iron can be granulated to a particle size below the specified size. However, as mentioned above, setting up multiple inclined platforms will make the device (equipment) larger in the height direction. In addition to the problem of height limitation, there is also the disadvantage of increased equipment costs and construction costs. In addition, the inclined platform as the collision structure 5 is exposed to high-temperature molten iron, so regular maintenance is required, but the more inclined platforms are added, the more the number of replacements of the collision structure 5 increases, and the maintenance cost increases.

[0023] In the granular pig iron manufacturing apparatus of the present embodiment, the molten iron discharge port 4 provided at the bottom 3a of the receiving container 3 is designed so that the molten iron that collides with the collision structure 5 and flies can be granulated into a particle size of or less than a predetermined particle size. Figure 2This is a detailed view of the discharge port 4 for molten iron provided at the bottom 3a of the receiving container 3. The receiving container 3 of this embodiment is similar to the tundish used for continuous casting, and is a structure in which the inner side of the iron sheet is covered with refractory bricks in a shell-shaped shape with an upper opening, and a discharge port 4 for molten iron is provided at its bottom 3a. The discharge port 4 is configured such that a first flow path 9 provided above the refractory brick portion of the bottom 3a of the receiving container 3 and a second flow path 10 provided below the iron sheet portion are arranged in a continuous state up and down. Therefore, the molten iron in the receiving container 3 flows down to the bottom of the container 3 through the discharge port 4 in the order from the first flow path 9 of the refractory brick portion to the second flow path 10 of the iron sheet portion. The cross-sectional shapes of the first flow path 9 and the second flow path 10 are both circular.

[0024] In this embodiment, from Figure 2 It is also clear that the cross-sectional area of ​​the second flow path 10 located at the bottom is smaller than the cross-sectional area of ​​the first flow path 9 located at the top, and a step 11 is provided between the upper end opening position of the second flow path 10 and the lower end of the first flow path 9. In the present embodiment, the first flow path 9 and the second flow path 10 are both cylindrical shapes with the same upper and lower dimensions. Therefore, if the cross-sectional area of ​​the second flow path 10 located at the bottom is smaller than the cross-sectional area of ​​the first flow path 9, a step 11 is formed between the upper end opening position of the second flow path 10 and the lower end of the first flow path 9. In the discharge port 4 of the molten iron of the present embodiment, it is important that, as described later, a step 11 protruding from the lower end of the first flow path 9 is formed at the upper end opening position of the second flow path 10. In addition, in order to form the step 11, it is sufficient that the upper end opening area of ​​the second flow path 10 located at the bottom is smaller than the lower end opening area of ​​the first flow path 9 located at the top.

[0025] The inventors of the present application have conducted various studies on the requirements for not requiring so much downward flow distance of molten iron until the collision with the collision structure 5, and for granulating the molten iron to a particle size below a specified size after the collision with the collision structure 5. The collision structure 5 is composed of a refractory material, and is configured in such a way that the upper surface (collision surface) of the collision structure 5 is located directly below the discharge port 4 of the molten iron in the vertical direction. The molten iron that has collided with the upper surface of the collision structure 5 is scattered in a manner that spreads outward from the outer periphery of the collision structure 5. In order to make the spread of the scattered molten iron uniform throughout the entire periphery of the collision structure 5, the collision surface of the collision structure 5 is preferably circular. Similarly, in order to stabilize the spread of the scattered molten iron, the collision surface of the collision structure 5 is preferably flat (horizontal plane).

[0026] The molten iron scattered radially outward from the circular and flat upper surface (collision surface) of the collision structure 5 spreads in a spherical shape like an umbrella (see Figure 4 , Figure 5). Since the molten iron is granulated outside the area that continuously expands in the umbrella shape, when the expansion (area) of the umbrella shape is large, the molten iron is connected in a film shape and is difficult to granulate. That is, the following situation was found: if the expansion (area) of the umbrella shape can be reduced, the molten iron can be easily granulated, and by doing so, the particle size can also be reduced. The following situation was further found: the more stable the flow of the molten iron before colliding with the collision structure 5, the greater the expansion of the umbrella shape after the collision. Therefore, in order to reduce the expansion of the umbrella shape, it is only necessary to give a velocity distribution to the flow velocity in the cross section of the flow of the molten iron flowing down from the discharge port 4. When the flow velocity in the cross section of the flow of the molten iron is the same, even if the molten iron collides with the collision structure, it is easy to maintain a uniform velocity distribution. The molten iron after colliding with the collision structure mostly expands in a film shape, forming a large umbrella and forming relatively large particles.

[0027] In order to give a velocity distribution to the flow velocity in the cross section of the flow of molten iron, for example, it is conceivable to set an obstacle at the outlet of the discharge port 4. That is, by setting an obstacle at the outlet of the discharge port 4, the velocity near the obstacle is reduced, and the velocity distribution can be given to the flow velocity in the cross section of the flow of molten iron. However, there are cases where a solid substance (slag) called slag flows in the molten iron. Therefore, since setting an obstacle at the outlet of the discharge port 4 may cause slag to accumulate and hinder the flow or block the discharge port 4, it is not practical.

[0028] Therefore, instead of setting an obstacle at the outlet of the discharge port 4, the velocity distribution is set by emphasizing the inflow of molten iron from the vicinity of the outlet of the discharge port 4. In order to obtain the velocity distribution of the flow velocity in the cross section of the flow of molten iron, it is sufficient to add an element that generates the velocity distribution in the cross section to the flow of the molten iron before the molten iron flows down from the receiving container 3. In the present embodiment, when the molten iron flows from the upper first flow path 9 to the lower second flow path 10, the molten iron collides with the step 11 at the upper end position of the opening of the second flow path 10, and the molten iron flows from the peripheral wall side of the first flow path 9 to the central part. As described above, when there is a step 11 of reduced diameter in the middle of the flow path of the fluid, stagnation occurs at the outermost part of the step 11, and the fluid is concentrated inside the step 11 in a manner of flowing from the peripheral wall side to the central part. As a result, in the second flow path 10, a velocity distribution is generated in which the flow velocity in the central part of the cross section is greater than the flow velocity in the peripheral wall part.

[0029] Figure 3In order to simulate the flying state of molten iron after the collision, the flow velocity in the case where there is a velocity distribution in the cross section of the molten iron flow and the case where there is no velocity distribution in the cross section of the molten iron flow are schematically shown. The radial position in the cross section is represented by the ratio of the radial position to the diameter of the cross section. The double-dotted line in the figure represents the case where the flow velocity in the cross section of the molten iron flow is constant at the average velocity Ve, that is, the state without velocity distribution. The solid line in the figure sets the flow velocity at the central part of the cross section of the molten iron flow before the collision to about twice the average velocity Ve, and on the other hand, at the peripheral part of the cross section, the flow velocity is set to approximately 0. That is, the latter is the flow velocity of the molten iron based on the discharge port 4 of the present embodiment, and the former is the flow velocity based on the discharge port 4 of the molten iron in the past without steps.

[0030] The scattering state of the molten iron after the collision corresponding to the flow velocity in the cross section of the molten iron flowing down is simulated as described below. When the discharge port 4 is composed of only the second flow path 10 and the molten iron discharge port 4 has no step, that is, when there is no flow velocity change in the cross section of the molten iron flowing down, the molten iron film expands in an umbrella shape, and the molten iron outside the molten iron tends to be connected and is difficult to be granulated to a particle size below the specified size (see Figure 5 On the other hand, when there is a step 11 at the outlet 4 of the molten iron, that is, when there is a change in the flow velocity of the molten iron in the flowing section, the umbrella-shaped molten iron film becomes smaller, and the molten iron granules on the outside thereof are of the same particle size, and the particle size is smaller (refer to Figure 4 ). This can also be considered to be caused by the collision of a part of the molten iron that has collided with the upper surface (collision surface) of the collision structure 5 with each other. If the particle size of the granulated molten iron is equally small, after falling into the cooling water, these granulated molten irons are cooled and solidified in the same way, so it is difficult for them to stick together in the cooling water. Therefore, the particle size of the granulated pig iron after cooling can be reduced, and there is no possibility of water vapor explosion.

[0031] In the present embodiment, the cross-sections of the first flow path 9 and the second flow path 10 are set to be circular, but the cross-sections of the respective flow paths 9 and 10 may be shapes other than circular. The size of the flow path when the cross-section is circular can be represented by the diameter, whereas the size of the flow path when the cross-section is not circular can be represented by the hydraulic diameter. The hydraulic diameter DH is represented as follows using the cross-sectional area A and the perimeter P.

[0032] DH=4A / P

[0033] The step 11 formed between the upper end position of the opening of the second flow path 10 and the lower end of the first flow path 9 is preferably uniform around the upper end opening of the second flow path 10. In order to cause the molten iron flowing in the first flow path 9 to produce a rapid speed change at the step portion and produce a velocity distribution of the molten iron in the cross section of the second flow path 10, it is necessary that the hydraulic diameter of the upper end cross section of the second flow path 10 is less than 80% of the hydraulic diameter of the lower end cross section of the first flow path 9. On the other hand, if the upper end opening area of ​​the second flow path 10 is too small, it is difficult to produce a velocity distribution of the molten iron in the cross section of the second flow path 10. Therefore, the hydraulic diameter of the upper end cross section of the second flow path 10 is set to be more than 10% of the hydraulic diameter of the lower end cross section of the first flow path 9. It should be noted that the peripheral portion of the first flow path 9 can also be chamfered at the upper end opening position of the first flow path 9.

[0034] In addition, if the flow path length of the second flow path 10 is too large, there is the possibility that the flow velocity of the molten iron is stable while passing through the second flow path 10, and sufficient velocity distribution cannot be obtained in the cross section of the molten iron flowing down from the discharge port 4. Therefore, the flow path length of the second flow path 10 is smaller than the flow path length of the first flow path 9, and it is preferred that the flow path length of the second flow path 10 is less than 50% of the flow path length of the first flow path 9. In addition, when the second flow path 10 is considered as a pipeline, if the pipeline length becomes larger, the boundary layer generated on the inner wall of the pipeline develops, making the velocity distribution of the molten iron in the cross section generated in the step portion negligible. This phenomenon occurs when the pipeline length is about 20 times the pipeline diameter, and therefore, the flow path length of the second flow path 10 is preferably less than 20 times the hydraulic diameter of the second flow path 10. It should be noted that the flow path length of the second flow path 10 can be set to any smaller one of less than 50% of the first flow path 9 and less than 20 times the hydraulic diameter of the second flow path 10. In addition, when the flow path length of the second flow path 10 is 0, the effect of the rapid speed change of the molten iron caused by the step 11 cannot be obtained, so the flow path length of the second flow path 10 is preferably greater than 1% of the hydraulic diameter of the second flow path 10.

[0035] Example

[0036] The following is an example of a molten iron outlet model used in the above simulation. In this model, the hydraulic diameter of the second flow path 10 is set to 76% of the hydraulic diameter of the first flow path 9, and the flow path length of the second flow path 10 is set to 7% of the hydraulic diameter of the second flow path 10. The simulation used Fluent (2021R1) of Ansys, which is an application software for fluid simulation. The physical properties of the fluid simulated by the molten iron are fluid density 8000kg / m 3, fluid annual 0.055 Pa·s, fluid surface tension 0.9N / m. The gas is assumed to be air, and the physical property values ​​set in Fluent are used. For the calculation conditions, unsteady-state calculation is performed, and the mixed phase flow is used in the VOF (Volume of Fluid) method, and the turbulence model is not considered for calculation. In addition, as the inflow condition from the receiving container 3 to the discharge port 4, it is set that the fluid (molten iron) flows in at the same speed of 4m / s.

[0037] As described above, the scattering state of molten iron after collision in the conventional granular pig iron manufacturing apparatus without a step in the middle of the discharge port 4 is shown in FIG. Figure 5 The scattering state of molten iron after collision using the granular pig iron manufacturing apparatus of the embodiment having the diameter reduction step 11 at the upper end opening position of the second flow path 10 below is shown in FIG. Figure 4 .Depend on Figure 5 It is clear that in the existing granular pig iron manufacturing apparatus, there is no velocity distribution of the flow velocity or the velocity distribution of the flow velocity is small in the cross section of the molten iron flow before the collision. The molten iron film that is scattered after the collision is large, and as a result, the granulated molten iron is connected on the outside. In the state where the granulated molten iron is connected like this, it is difficult to obtain granular pig iron with a particle size below the specified size. In addition, since it takes time to cool in the cooling water, the granular pig iron is easy to stick to each other. On the other hand, Figure 4 As shown, in the granular pig iron manufacturing apparatus of the embodiment in which the velocity distribution of the flow velocity in the cross section of the flow of the molten iron before the collision is large, the umbrella of the molten iron film that is scattered after the collision is small. The small umbrella of the molten iron film means that the molten iron in the scattered state is in a state where it is easy to break each other, and the particle size of the molten iron particles formed outside the umbrella is the same and small. Granular pig iron with the same small particle size is quickly and separately cooled and solidified in the cooling water, so the granular pig iron is less likely to stick together.

[0038] Thus, in the granulated pig iron manufacturing apparatus of the present embodiment, when the molten iron flows from the upper first flow path 9 to the lower second flow path 10, the molten iron in the first flow path 9 collides with the step 11 at the entrance of the second flow path 10 formed by the difference in opening area, and a rapid velocity change occurs. As a result, a velocity distribution of the flow velocity is generated in the cross section of the molten iron flowing down from the second flow path 10, and the molten iron that collides with the collision structure 5 and is scattered can be reliably granulated by this velocity distribution. As a result, even when the height of the apparatus is limited, the molten iron can be made into granular pig iron with a particle size of less than a predetermined particle size.

[0039] Furthermore, since both the first flow path 9 and the second flow path 10 are formed inside the bottom 3a of the receiving container 3, the distance that the molten iron flows down from the receiving container 3 to the collision structure 5 can be shortened, thereby reducing the height dimension of the device.

[0040] Furthermore, by evenly providing the steps 11 around the upper opening of the second flow path 10, the amount of molten iron flowing from the peripheral wall portion of the first flow path 9 to the central portion can be increased, thereby increasing the velocity distribution of the flow velocity in the cross section where the molten iron flows downward. As a result, the molten iron that has collided with the collision structure 5 and cooled can be reliably made into granular pig iron with a particle size of less than a predetermined particle size.

[0041] Furthermore, by setting the hydraulic diameter of the upper end section of the second flow path 10 to 10% to 80% of the hydraulic diameter of the lower end section of the first flow path 9 , a velocity distribution of the flow rate can be reliably generated in the cross section of the molten iron flowing down from the second flow path 10 .

[0042] Furthermore, by making the flow path length of the second flow path 10 shorter than the flow path length of the first flow path 9, preferably less than 50% of the flow path length of the first flow path 9, the velocity distribution of the flow velocity in the cross section of the molten iron flowing down from the second flow path 10 can be maintained.

[0043] The granular metal manufacturing device according to the embodiment has been described above, but the present invention is not limited to the structure described in the above embodiment, and various changes can be made within the scope of the gist of the present invention. For example, in the above embodiment, the first flow path 9 and the second flow path 10 are formed inside the bottom 3a of the receiving container 3, but these flow paths 9 and 10 only need to be formed in the area where the molten iron flows down from the inside of the receiving container 3 toward the collision structure 5. However, by forming the first flow path 9 and the second flow path 10 inside the bottom 3a of the receiving container 3, the distance in the height direction from the receiving container 3 to the collision structure 5 can be shortened, thereby miniaturizing the device.

[0044] In the above embodiment, only the case of producing granular pig iron from molten iron is described in detail. However, the granular metal production device of the present invention can be applied to any metal as long as it is a device that makes the molten metal contained in the container 3 flow down, makes the molten metal collide with the collision structure 5 to granulate, and then solidifies the molten metal to produce granular metal.

[0045] Description of symbols 3 Receiving container (container) 3a Bottom 4 Exhaust port 5 Collision Structure 6 sink 9 first flow path 10 Second flow path 11 steps.

Claims

1. A granular metal manufacturing device, which makes molten metal contained in a container flow down from the container, makes the molten metal collide with a collision structure to granulate, and then solidifies the molten metal to manufacture granular metal, wherein: The first flow path and the second flow path are arranged in a continuous state at upper and lower positions, and the first flow path and the second flow path are used to make the molten metal flow from the container toward the collision structure. The upper end opening area of ​​the second flow path located at the bottom is smaller than the lower end opening area of ​​the first flow path located at the top, and a step is provided between the upper end opening position of the second flow path and the lower end of the first flow path.

2. The granular metal manufacturing device according to claim 1, wherein: The first flow path and the second flow path are both disposed inside the bottom of the container.

3. The granular metal production device according to claim 1 or 2, wherein: The steps are evenly arranged around the upper end opening of the second flow path.

4. The granular metal production device according to any one of claims 1 to 3, wherein: The hydraulic diameter of the upper end cross section of the second flow channel is 10% to 80% of the hydraulic diameter of the lower end cross section of the first flow channel.

5. The granular metal production device according to any one of claims 1 to 4, wherein: A flow path length of the second flow path is shorter than a flow path length of the first flow path.

6. The granular metal manufacturing device according to claim 5, wherein: A flow path length of the second flow path is less than or equal to 50% of a flow path length of the first flow path.

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