Refining method and converter

Abstract

To provide a refining method and a converter capable of suppressing sloshing in the converter in which bottom blowing tuyeres are dispersedly arranged in a furnace bottom,.SOLUTION: The refining method for blowing gas into a refining vessel from a plurality of gas discharge tuyeres disposed at the bottom of the refining vessel is characterized in that an eccentricity O represented by formula (1) is less than 0.6.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a refining method and a converter.

Background Art

[0002] In a converter for melting steel, generally, oxygen or an inert gas such as argon or nitrogen is blown from the bottom of the furnace to stir the inside of the furnace. For example, as a device for refining hot metal, a top-bottom blown converter having an upper blowing lance and a plurality of bottom blowing tuyeres provided at the bottom is used. In the top-bottom blown converter, hot metal is oxidized and refined by blowing oxygen gas from the upper blowing lance into the hot metal in the furnace, and at the same time, stirring gas (bottom blowing gas) is blown from the bottom blowing tuyeres to stir the hot metal, thereby promoting the refining reaction between slag and metal. In order to achieve higher blowing efficiency and faster processing speed, it is also necessary to improve the stirring efficiency of slag and metal by increasing the flow rate of the bottom blowing gas.

[0003] However, when the flow rate of the bottom blowing gas is increased, the fluctuation of the molten metal in the furnace becomes large and the scattering of the molten metal becomes intense. This phenomenon is called sloshing. When the scattered molten metal adheres to the upper blowing lance, the furnace mouth, etc., it causes a reduction in yield and loss time for removing ingots, leading to a reduction in productivity.

[0004] As a factor inducing sloshing, in addition to an increase in the flow rate of the bottom blowing gas, the arrangement of the bottom blowing tuyeres is cited. For example, Non-Patent Document 1 describes that depending on the arrangement of the bottom blowing tuyeres, the fluctuation of the molten metal is roughly classified into two types (Type A and Type B). Type A is characterized in that the blown bottom blowing gas forms a single-phase gas-liquid coexistence region during the rising process and sways left and right like the vibration of the liquid in a U-tube. Type B is characterized in that the blown gas forms two gas-liquid coexistence regions, and each repeats the vibration of approaching and separating. At this time, it has been pointed out that the fluctuation of Type A causes intense scattering of the molten metal.

[0005] Also, as a method for avoiding sloshing, for example, the methods of Patent Documents 1 to 4 can be cited. In Patent Documents 1 to 3, the arrangement of the bottom blowing tuyeres of the converter for suppressing sloshing is defined. In Patent Document 1, the bottom blowing tuyeres are arranged parallel to the trunnion axis of the furnace body, and the distance between the trunnion axis and the arrangement and the width of the arrangement area are defined. Also in Patent Documents 2, 3, and 4, while the bottom blowing tuyeres are arranged parallel to the trunnion axis, the distance between the tuyeres and the distance between the tuyere and the trunnion axis are defined.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Non-Patent Documents

[0007]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0008] However, in Patent Documents 1 to 4, since the tuyere group is not dispersed and is arranged in a row, there is a problem that the gas bubbles blown from the bottom blowing tuyeres cannot efficiently stir the molten metal. The configurations described in Patent Documents 1 to 4 are targeted at bottom blowing converters with a large flow rate of bottom blowing gas, so even if the tuyere group is arranged in a row, it is possible to cause a refining reaction at a sufficiently high speed. On the other hand, in an upper bottom blowing converter where the stirring power is inferior to that of a bottom blowing converter, in order to perform efficient stirring with a low flow rate of bottom blowing gas, the tuyeres are arranged dispersedly on the furnace bottom.

[0009] The present invention has been made to solve the above-described problems, and an object thereof is to provide a refining method and a converter capable of suppressing sloshing in a converter in which bottom blowing tuyeres are dispersedly arranged on the furnace bottom.

Means for Solving the Problems

[0010] The refining method according to the present invention is a refining method in which gas is blown into a refining vessel from a plurality of gas discharge tuyeres arranged at the bottom of the refining vessel, and is characterized in that the eccentricity O represented by the following formula (1) is less than 0.6.

Number

[0011] The refining method according to the present invention is characterized in that, in the above invention, the eccentricity O represented by the formula (1) is 0.2 or more and less than 0.6.

[0012] The refining method according to the present invention is characterized in that, in the above invention, the refining vessel is used in a converter having a function of blowing oxygen from an upper blowing lance.

[0013] The converter according to the present invention is a converter including a plurality of gas discharge tuyeres arranged at the bottom of a refining vessel, and configured to blow gas into the refining vessel from the plurality of gas discharge tuyeres, wherein the gas discharge tuyeres are arranged at the bottom of the refining vessel such that the eccentricity O represented by the following formula (2) is less than 0.6.

Number

[0014] The converter according to the present invention is characterized in that, in the above invention, the eccentricity represented by the formula (2) is 0.2 or more and less than 0.6.

[0015] The converter according to the present invention is characterized in that, in the above invention, it is provided with an upper blowing lance for blowing oxygen into the inside of the refining vessel.

Advantages of the Invention

[0016] According to the present invention, by using a refining method using a refining vessel configured such that the eccentricity O obtained using the absolute value by summing the vectors of each gas discharge tuyere provided at the bottom of the refining vessel is less than 0.6, it is possible to achieve both ensuring the stirring force of hot metal and preventing slopping.

Brief Description of the Drawings

[0017]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

[0018] Hereinafter, with reference to the drawings, a refining method and a converter in an embodiment of the present invention will be specifically described. Note that the constituent elements in the following embodiments include those that can be replaced by those skilled in the art, those that are easy to replace, or those that are substantially the same.

[0019] FIG. 1 is a schematic diagram showing a top-bottom blown converter in an embodiment. The top-bottom blown converter 1 includes an upper blowing lance 2 and a furnace body 3. The furnace body 3 is a molten metal container such as a refining container, and is supported by a trunnion shaft 4 and a base 5. The furnace body 3 is the converter main body. In the top-bottom blown converter 1, the furnace body 3 is tilted by the rotation of the trunnion shaft 4, and slag 6 is discharged and hot metal 7 is tapped.

[0020] In the blowing in the top-bottom blown converter 1, after charging the hot metal 7 into the furnace body 3, a flux such as lime is added from above the furnace, and nitrogen or argon gas and oxygen are blown from a plurality of gas discharge tuyeres (hereinafter referred to as bottom blowing tuyeres) 9 provided on the furnace bottom 8, while oxygen is blown from the upper blowing lance 2 to remove impurities such as carbon and phosphorus in the hot metal 7. At this time, the stirring of the molten metal 10 is determined by the nozzle shape and oxygen flow rate of the upper blowing lance 2, the upper blowing conditions such as the distance between the upper blowing lance 2 and the bath surface, and the arrangement and gas flow rate of the bottom blowing tuyeres 9. The molten metal 10 is a molten metal containing the slag 6 and the hot metal 7. If the upper blowing conditions are changed to increase the stirring, the scattering of the hot metal 7 increases and the yield decreases, so it is desirable to increase the stirring by the bottom blowing conditions. Also, if the number of tuyeres of the bottom blowing tuyeres 9 is small, the inside of the furnace cannot be stirred uniformly, and if the number of tuyeres is large, the gas flow rate per tuyere becomes small and the stirring decreases, so it is desirable to use 6 to 8 tuyeres.

[0021] Next, the arrangement of the bottom-blowing tuyeres 9 will be described with reference to FIG. 2. The upper-bottom-blowing converter 1 is a converter in which the bottom-blowing tuyeres 9 are dispersedly arranged on the furnace bottom. As a result of intensive studies on the arrangement of the bottom-blowing tuyeres 9 by the inventors, it was clarified that in the water model experiment described later, when the arrangement of the bottom-blowing tuyeres 9 is largely biased within the furnace bottom 8, the vibration of the furnace body 3 becomes intense. Therefore, as shown in FIG. 2, the inventors defined the position vector of the center of the tuyere i in the horizontal cross-section with the center A of the furnace bottom 8 (hereinafter referred to as the furnace bottom center) as the origin as r i and quantified the tuyere arrangement by adding up the position vectors of all the tuyeres.

[0022] Furthermore, the inventors combined the fact that the influence of the tuyeres close to the furnace bottom center A on the vibration of the furnace body 3 is large and that the higher the height of the molten metal in the refining vessel, the greater the vibration of the furnace body 3, and devised an evaluation formula. The evaluation formula is as shown in the following formula (3).

[0023]

Equation

[0024] However, in the above formula (3), O is the eccentricity, n is the number of bottom-blowing tuyeres, H is the height (m) of the molten metal in the refining vessel, r i is the vector (m) from the furnace bottom center to the tuyere i in the horizontal cross-section of the refining vessel, and R i is the distance (m) from the furnace bottom center to the tuyere i in the horizontal cross-section of the refining vessel.

[0025] Also, the inventors clarified the conditions for suppressing sloshing based on the evaluation formula shown in the above formula (3). Specifically, by arranging the bottom-blowing tuyeres 9 on the furnace bottom 8 so that the eccentricity O of the above formula (3) satisfies 0.6 or less, it becomes possible to suppress sloshing in the refining process. The eccentricity O represents the degree of bias in the arrangement of the bottom-blowing tuyeres 9 on the furnace bottom 8.

[0026] When the eccentricity O is zero, it indicates that the bottom blowing tuyere 9 is arranged in the furnace bottom 8 without any bias. When the eccentricity O is greater than zero, it indicates that the bottom blowing tuyere 9 is arranged in a biased manner within the furnace bottom 8. And as the eccentricity O increases, it represents that the degree of bias in the arrangement of the bottom blowing tuyere 9 within the furnace bottom 8 becomes larger.

[0027] In the above formula (3), (r i / R i 2 ) divides the vector from the furnace bottom center A to the tuyere i by the straight-line distance from the furnace bottom center A to the tuyere i, which represents a vector with a magnitude equal to the reciprocal of the distance from the furnace bottom center A to the tuyere i. From the examination results, it was found that the tuyeres closer to the furnace bottom center A are more likely to promote sloshing than those farther from the furnace bottom center A. Furthermore, since sloshing is promoted more as the bias of the tuyeres in the furnace bottom 8 increases, the total value obtained by summing up (r i / R i 2 ) for each tuyere was adopted as an index to represent the bias of the tuyeres.

[0028] Also, H is the height (m) of the molten metal in the refining vessel. It was confirmed that as H increases, the gas blown from the furnace bottom 8 rises and spreads, combines with the gas blown from the nearby tuyeres, and has a greater excitation force. Therefore, formula (3) was in a form multiplied by H.

[0029] As described above, according to the embodiment, since it is a refining method using a refining vessel having a tuyere arrangement in which the vectors of each bottom blowing tuyere 9 provided in the furnace bottom 8 are summed up and the absolute value thereof falls within a predetermined range, it is possible to achieve both ensuring the stirring force and preventing sloshing. Thereby, it is possible to suppress the occurrence of sloshing while ensuring the stirring force of the hot metal 7.

[0030] Also, it is possible to suppress the oscillation of the molten metal 10 due to the integration of the bottom blowing gas bubbles from the bottom blowing tuyere 9, and it is possible to suppress the occurrence of sloshing. Thereby, it becomes possible to suppress the adhesion of the metal charge to the top blowing lance 2 etc., and the effect of improving productivity can be obtained.

Example

[0031] Next, an experiment for measuring the acceleration of the vessel vibration due to the arrangement of the bottom blowing tuyeres will be described. Fig. 3 is a schematic diagram showing the water model apparatus. The water model apparatus 100 has a vessel 101 at a 1 / 10 scale of the actual machine, a top blowing lance 102, and a bottom blowing tuyere 103. At the bottom (hereinafter referred to as the furnace bottom) 110 of the vessel 101, a bottom blowing tuyere facility including a plurality of bottom blowing tuyeres 103 is provided. The vessel 101 is supported by a trunnion shaft 104 extending in the horizontal direction. The trunnion shaft 104 is supported by a support column 105.

[0032] The top blowing lance 102 is a pipe extending vertically from above the vessel 101 into the vessel 101, and blows gas into the vessel 101 from a top blowing nozzle attached to the tip. This top blowing nozzle has five holes, and N2 gas is blown from each hole at an inclination angle of 16° from the vertical direction. At this time, the distance (lance height) between the nozzle tip 106 and the stationary water surface 107 was set to 0.23 m. The experimental conditions of this water model experiment are shown in Table 1.

[0033]

Table 1

[0034] Table 1 also shows the refining conditions (operating conditions of the actual machine) in the actual converter. The experimental conditions of the water model were calculated so that the modified Froude number would be equal to the operating conditions of the actual machine. The modified Froude number Fr´ is represented by the following formula (4).

[0035]

Equation

[0036] In the above formula (4), ρ g is the gas density (kg / m 3 ), v is the gas flow velocity (m / s), ρ l is the liquid density (kg / m 3 ), and g is the gravitational acceleration (m / s2 ) and d is the nozzle diameter (m). Each value is shown in Table 2.

[0037]

Table 2

[0038] As shown in Table 2, the experimental conditions of the water model experiment were set so that the modified Froude number in the actual machine and the modified Froude number in the water model experiment would be the same.

[0039] Figure 4 is a schematic diagram showing the arrangement of the bottom blowing tuyeres used in the water model experiment. As shown in Figure 4, in the furnace bottom 110 with a diameter of 330 mm, bottom blowing tuyeres 103 with a hole diameter of 2 mm were provided at 30° intervals on the circumference of the inner circle with a diameter of 120 mm centered on the center of the furnace bottom 110 (the center of the furnace bottom) and on the circumference of the outer circle with a diameter of 230 mm. On the circumferences of the inner circle and the outer circle, there are candidate positions where gas discharge tuyeres can be installed at 30° intervals at positions with the same phase between the inner circle and the outer circle. A plurality of bottom blowing tuyeres 103 are arranged on the circumferences of two concentric circles with different diameters on the furnace bottom 110.

[0040] In this case, the diameters of the inner circle and the outer circle are set so as to satisfy both the first condition and the second condition. The first condition is that the diameter of the inner circle is larger than one-third of the diameter of the furnace bottom 110 and smaller than half of the diameter of the furnace bottom 110. The second condition is that the diameter of the outer circle is larger than half of the diameter of the furnace bottom 110.

[0041] Also, pipes were connected from the gas branch header to each tuyere so that an equal flow rate of bottom blowing N2 gas would flow from each gas discharge tuyere. When the trunnion axis 104 is taken as the X-axis and the water outlet side is taken as the positive direction of the Y-axis when looking at the furnace bottom 110 from above the container 101, the coordinates of each tuyere of the bottom blowing tuyere facility are shown in Table 3.

[0042]

Table 3

[0043] As shown in Table 3, the bottom blowing tuyere 103 can be arranged at the positions of Nozzles No. 1 to 24. The positions of Nozzles No. 1 to 12 are provided on the circumference of the inner circle with a diameter of 120 mm centered on the center of the furnace bottom 110. The positions of Nozzles No. 13 to 24 are provided on the circumference of the outer circle with a diameter of 230 mm centered on the center of the furnace bottom 110.

[0044] In the water model experiment, with 30 L or 40 L of water in the container 101, N2 gas at a predetermined flow rate was blown from each tuyere of the top blowing lance 102 and the bottom blowing tuyere equipment for 10 minutes. During this period, the acceleration in the direction parallel to the trunnion axis 104 was measured from the accelerometer installed on the trunnion axis 104. Sloshing occurs only for a short fixed period during the blowing process, and only a rapid increase in acceleration is observed during its occurrence. In the water model experiment, N2 gas was blown from each tuyere of the top blowing lance 102 and the bottom blowing tuyere equipment to stir the water in the container 101, and the maximum acceleration measured by the accelerometer during the 10 minutes was compared. The experimental results of the water model experiment are summarized in Table 4.

[0045]

Table 4

[0046] As shown in Table 4, the acceleration of the container vibration was measured by changing the water volume in the container 101 and the position of the bottom blowing tuyere 103. Invention Examples 1 to 4, 9 to 12 and Comparative Examples 1 to 6 are examples where the water volume in the container 101 is 30 L and the water height is 180 mm. Invention Examples 5 to 8, 13 to 15 and Comparative Examples 7 to 15 are examples where the water volume in the container 101 is 40 L and the water height is 218 mm. Also, Invention Examples 1 to 8 and Comparative Examples 1 to 13 are examples of the bottom blowing tuyere equipment with six tuyeres. Invention Examples 9 to 15 and Comparative Examples 14 to 15 are examples of the bottom blowing tuyere equipment with eight tuyeres. The eccentricity O was obtained by the above formula (3). The maximum acceleration is the maximum value among the accelerations measured by the accelerometer.

[0047] Meanwhile, in order to measure the uniform mixing time, a KCl solution was dropped from the upper part of the container 101 at a rate of 0.2 ml / second for 15 ml, and the electrical conductivity was measured with the electrical conductivity meter 108 placed at the furnace bottom 110. The case where the electrical conductivity of the water bath was continuously recorded for 5 seconds or more within the range of ±2% of the value of the electrical conductivity calculated from the KCl concentration when the dropped KCL was completely mixed was defined as uniform mixing. The time from dropping the KCL aqueous solution until the electrical conductivity reached the equilibrium value was defined as the uniform mixing time.

[0048] As shown in FIG. 5, the bottom blowing tuyere facilities of Invention Examples 1 to 15 include an even number of bottom blowing tuyeres 103 arranged on the circumference of the inner circle and an even number of bottom blowing tuyeres 103 arranged on the circumference of the outer circle at the furnace bottom 110, and have an even number of bottom blowing tuyeres 103 in total. The bottom blowing tuyere facilities of Invention Examples 1 to 2, 4 to 6, and 8 include two bottom blowing tuyeres 103 arranged on the circumference of the inner circle and four bottom blowing tuyeres 103 arranged on the circumference of the outer circle, and have a total of six bottom blowing tuyeres 103. The bottom blowing tuyere facilities of Invention Examples 3 and 7 include four bottom blowing tuyeres 103 arranged on the circumference of the inner circle and two bottom blowing tuyeres 103 arranged on the circumference of the outer circle, and have a total of six bottom blowing tuyeres 103. The bottom blowing tuyere facilities of Invention Examples 9 to 15 include two bottom blowing tuyeres 103 arranged on the circumference of the inner circle and six bottom blowing tuyeres 103 arranged on the circumference of the outer circle, and have a total of eight bottom blowing tuyeres 103.

[0049] In the bottom blowing tuyere facility of Invention Example 1, bottom blowing tuyeres 103 are provided at the positions of nozzles No. 1 and 7 on the circumference of the inner circle and at the positions of nozzles No. 14, 20, 21, and 24 on the circumference of the outer circle. Regarding the inner circle, the positional relationship between nozzle No. 1 and nozzle No. 7 is a point-symmetric positional relationship with the center of the furnace bottom 110 as the center of symmetry. Regarding the outer circle, the positional relationship between nozzle No. 14 and nozzle No. 20 is a point-symmetric positional relationship with the center of the furnace bottom 110 as the center of symmetry on a diameter line different from that of nozzles No. 1 and 7 of the inner circle. Also, the bottom blowing tuyere facility of Invention Example 5 is configured identically to the bottom blowing tuyere facility of Invention Example 1. Invention Example 1 and Invention Example 5 have the same arrangement of bottom blowing tuyeres 103, but different water amounts and water heights. As shown in Table 4, Invention Example 1 has a maximum acceleration of 105 μm / s2 It is such that the uniform mixing time is 31.7 s and the eccentricity O is 0.37. Invention Example 5 has a maximum acceleration of 114 μm / s 2 It is such that the uniform mixing time is 42.0 s and the eccentricity O is 0.45.

[0050] In the bottom blowing tuyere facility of Invention Example 2, bottom blowing tuyeres 103 are provided at the positions of nozzles No. 4 and 10 on the circumference of the inner circle and at the positions of nozzles No. 13, 17, 20, and 23 on the circumference of the outer circle. Regarding the inner circle, the positional relationship between nozzle No. 4 and nozzle No. 10 is a point-symmetric positional relationship with the center of the furnace bottom 110 as the center of symmetry. Regarding the outer circle, the positional relationship between nozzle No. 17 and nozzle No. 23 is a point-symmetric positional relationship with the center of the furnace bottom 110 as the center of symmetry on a diameter line different from that of nozzles No. 4 and 10 of the inner circle. Also, the bottom blowing tuyere facility of Invention Example 6 is configured identically to the bottom blowing tuyere facility of Invention Example 2. Invention Example 2 and Invention Example 6 have the same arrangement of the bottom blowing tuyere 103, but different water volumes and water heights. As shown in Table 4, Invention Example 2 has a maximum acceleration of 130 μm / s 2 It is such that the uniform mixing time is 48.1 s and the eccentricity O is 0.14. Invention Example 6 has a maximum acceleration of 101 μm / s 2 It is such that the uniform mixing time is 52.0 s and the eccentricity O is 0.16.

[0051] In the bottom blowing tuyere facility of Invention Example 3, the bottom blowing tuyeres 103 are provided at the positions of nozzles No. 1, 3, 7, 9 on the circumference of the inner circle and at the positions of nozzles No. 18, 24 on the circumference of the outer circle. Regarding the inner circle, the positional relationship between nozzle No. 1 and nozzle No. 7 and the positional relationship between nozzle No. 3 and nozzle No. 9 are point-symmetric positional relationships with the center of the furnace bottom 110 as the center of symmetry. The diameter lines of nozzles No. 1, 7 are different from those of nozzles No. 3, 9. Regarding the outer circle, the positional relationship between nozzle No. 18 and nozzle No. 24 is a point-symmetric positional relationship with the center of the furnace bottom 110 as the center of symmetry on a diameter line different from that of nozzles No. 1, 7 of the inner circle and on a diameter line different from that of nozzles No. 3, 9 of the inner circle. Also, the bottom blowing tuyere facility of Invention Example 7 is configured identically to the bottom blowing tuyere facility of Invention Example 3. Invention Example 3 and Invention Example 7 have the same arrangement of the bottom blowing tuyeres 103, but different water amounts and water heights. As shown in Table 4, Invention Example 3 has a maximum acceleration of 115 μm / s 2 and a uniform mixing time of 53.6 s and an eccentricity O of 0.00. Invention Example 7 has a maximum acceleration of 131 μm / s 2 and a uniform mixing time of 57.9 s and an eccentricity O of 0.00.

[0052] In the bottom blowing tuyere facility of Invention Example 4, the bottom blowing tuyeres 103 are provided at the positions of nozzles No. 4, 10 on the circumference of the inner circle and at the positions of nozzles No. 13, 14, 20, 23 on the circumference of the outer circle. Regarding the inner circle, the positional relationship between nozzle No. 4 and nozzle No. 10 is a point-symmetric positional relationship with the center of the furnace bottom 110 as the center of symmetry. Regarding the outer circle, the positional relationship between nozzle No. 14 and nozzle No. 20 is a point-symmetric positional relationship with the center of the furnace bottom 110 as the center of symmetry on a diameter line different from that of nozzles No. 4, 10 of the inner circle. Also, the bottom blowing tuyere facility of Invention Example 8 is configured identically to the bottom blowing tuyere facility of Invention Example 4. Invention Example 4 and Invention Example 8 have the same arrangement of the bottom blowing tuyeres 103, but different water amounts and water heights. As shown in Table 4, Invention Example 4 has a maximum acceleration of 131 μm / s 2 and a uniform mixing time of 33.0 s and an eccentricity O of 0.45. Invention Example 8 has a maximum acceleration of 125 μm / s2 wherein the uniform mixing time is 41.0 s and the eccentricity O is 0.55.

[0053] In the bottom tuyere equipment of Invention Example 9, bottom tuyeres 103 are provided at the positions of nozzles No. 6 and 12 on the circumference of the inner circle and at the positions of nozzles No. 14, 16, 17, 20, 22, and 23 on the circumference of the outer circle. Regarding the inner circle, the positional relationship between nozzle No. 6 and nozzle No. 12 is a point-symmetrical positional relationship with the center of the furnace bottom 110 as the center of symmetry. Regarding the outer circle, the positional relationship between nozzle No. 14 and nozzle No. 20, the positional relationship between nozzle No. 16 and nozzle No. 22, and the positional relationship between nozzle No. 17 and nozzle No. 23 are each in a point-symmetrical positional relationship with the center of the furnace bottom 110 as the center of symmetry on a diameter line different from nozzles No. 6 and 12 of the inner circle. Further, the bottom tuyere equipment of Invention Example 13 is configured identically to the bottom tuyere equipment of Invention Example 9. Invention Example 9 and Invention Example 13 have the same arrangement of the bottom tuyeres 103, but different amounts of water and water heights. As shown in Table 4, Invention Example 9 has a maximum acceleration of 106 μm / s 2 wherein the uniform mixing time is 56.0 s and the eccentricity O is 0.00. Invention Example 13 has a maximum acceleration of 152 μm / s 2 wherein the uniform mixing time is 60.0 s and the eccentricity O is 0.00.

[0054] In the bottom blowing tuyere facility of Invention Example 10, bottom blowing tuyeres 103 are provided at the positions of nozzles No. 4 and 10 on the circumference of the inner circle, and at the positions of nozzles No. 15, 17, 18, 22, 23, and 24 on the circumference of the outer circle. Regarding the inner circle, the positional relationship between nozzle No. 4 and nozzle No. 10 is a point-symmetric positional relationship with the center of the furnace bottom 110 as the center of symmetry. Regarding the outer circle, the positional relationship between nozzle No. 17 and nozzle No. 23 and the positional relationship between nozzle No. 18 and nozzle No. 24 are both in a point-symmetric positional relationship with the center of the furnace bottom 110 as the center of symmetry on different diameter lines from nozzles No. 4 and 10 of the inner circle. Further, the bottom blowing tuyere facility of Invention Example 14 is configured identically to the bottom blowing tuyere facility of Invention Example 10. Invention Example 10 and Invention Example 14 have the same arrangement of the bottom blowing tuyere 103, but different water volumes and water heights. As shown in Table 4, Invention Example 10 has a maximum acceleration of 135 μm / s 2 and a uniform mixing time of 45.2 s and an eccentricity O of 0.10. Invention Example 14 has a maximum acceleration of 146 μm / s 2 and a uniform mixing time of 52.0 s and an eccentricity O of 0.12.

[0055] In the bottom blowing tuyere facility of Invention Example 11, bottom blowing tuyeres 103 are provided at the positions of nozzles No. 2 and 9 on the circumference of the inner circle, and at the positions of nozzles No. 13, 16, 19, 20, 21, and 24 on the circumference of the outer circle. Regarding the outer circle, the positional relationship between nozzle No. 13 and nozzle No. 19 is a point-symmetric positional relationship with the center of the furnace bottom 110 as the center of symmetry. Further, the bottom blowing tuyere facility of Invention Example 15 is configured identically to the bottom blowing tuyere facility of Invention Example 11. Invention Example 11 and Invention Example 15 have the same arrangement of the bottom blowing tuyere 103, but different water volumes and water heights. As shown in Table 4, Invention Example 11 has a maximum acceleration of 136 μm / s 2 and a uniform mixing time of 40.3 s and an eccentricity O of 0.31. Invention Example 15 has a maximum acceleration of 116 μm / s 2 and a uniform mixing time of 40.4 s and an eccentricity O of 0.37.

[0056] In the bottom-blow tuyere facility of Invention Example 12, bottom-blow tuyeres are provided at the positions of Nozzles No. 3 and 5 on the circumference of the inner circle and at the positions of Nozzles No. 15, 18, 20, 21, 23, and 24 on the circumference of the outer circle. Regarding the outer circle, the positional relationship between Nozzle No. 15 and Nozzle No. 21 and the positional relationship between No. 18 and No. 24 are in a point-symmetric positional relationship with the center of the furnace bottom 110 as the center of symmetry on different diameter lines. As shown in Table 4, Invention Example 12 has a maximum acceleration of 161 μm / s 2 and a uniform mixing time of 32.0 s, and an eccentricity O of 0.55.

[0057] On the other hand, as shown in FIG. 6, the bottom-blow tuyere facilities of Comparative Examples 1 to 15 include a plurality of bottom-blow tuyeres 103 arranged on the circumference of the inner circle and a plurality of bottom-blow tuyeres 103 arranged on the circumference of the outer circle on the furnace bottom 110, and have an even number of bottom-blow tuyeres 103 in total. The bottom-blow tuyere facilities of Comparative Examples 1 to 4, 6 to 11, and 13 include two bottom-blow tuyeres 103 arranged on the circumference of the inner circle and four bottom-blow tuyeres 103 arranged on the circumference of the outer circle, and have a total of six bottom-blow tuyeres 103. The bottom-blow tuyere facilities of Comparative Examples 5 and 12 include three bottom-blow tuyeres 103 arranged on the circumference of the inner circle and three bottom-blow tuyeres 103 arranged on the circumference of the outer circle, and have a total of six bottom-blow tuyeres 103. The bottom-blow tuyere facilities of Comparative Examples 14 to 15 include two bottom-blow tuyeres 103 arranged on the circumference of the inner circle and six bottom-blow tuyeres 103 arranged on the circumference of the outer circle, and have a total of eight bottom-blow tuyeres 103.

[0058] In the bottom-blow tuyere facility of Comparative Example 1, bottom-blow tuyeres 103 are provided at the positions of Nozzles No. 3 and 12 on the circumference of the inner circle and at the positions of Nozzles No. 14, 17, 23, and 24 on the circumference of the outer circle. Regarding the outer circle, the positional relationship between Nozzle No. 17 and Nozzle No. 23 is in a point-symmetric positional relationship with the center of the furnace bottom 110 as the center of symmetry. Also, the bottom-blow tuyere facility of Comparative Example 1 is configured identically to the bottom-blow tuyere facility of Comparative Example 8. Comparative Example 1 and Comparative Example 8 have the same arrangement of bottom-blow tuyeres 103 but different water volumes and water heights. As shown in Table 4, Comparative Example 1 has a maximum acceleration of 267 μm / s 2and the uniform mixing time is 31.7 s and the eccentricity O is 1.15. Comparative Example 8 has a maximum acceleration of 354 μm / s 2 and the eccentricity O is 1.39.

[0059] In the bottom blowing tuyere facility of Comparative Example 2, the bottom blowing tuyere 103 is provided at the positions of nozzles No. 10 and 12 on the circumference of the inner circle and at the positions of nozzles No. 20, 21, 22, and 24 on the circumference of the outer circle. Also, the bottom blowing tuyere facility of Comparative Example 2 is configured identically to the bottom blowing tuyere facility of Comparative Example 9. Comparative Example 2 and Comparative Example 9 have the same arrangement of the bottom blowing tuyere 103 but different water volumes and water heights. As shown in Table 4, Comparative Example 2 has a maximum acceleration of 351 μm / s 2 and the eccentricity O is 1.53. Comparative Example 9 has a maximum acceleration of 444 μm / s 2 and the eccentricity O is 1.85.

[0060] In the bottom blowing tuyere facility of Comparative Example 3, the bottom blowing tuyere 103 is provided at the positions of nozzles No. 3 and 5 on the circumference of the inner circle and at the positions of nozzles No. 15, 17, 22, and 24 on the circumference of the outer circle. Also, the bottom blowing tuyere facility of Comparative Example 3 is configured identically to the bottom blowing tuyere facility of Comparative Example 10. Comparative Example 3 and Comparative Example 10 have the same arrangement of the bottom blowing tuyere 103 but different water volumes and water heights. As shown in Table 4, Comparative Example 3 has a maximum acceleration of 237 μm / s 2 and the eccentricity O is 0.95. Comparative Example 10 has a maximum acceleration of 257 μm / s 2 and the eccentricity O is 1.15.

[0061] In the bottom-blow tuyere facility of Comparative Example 4, the bottom-blow tuyeres 103 are provided at the positions of nozzles No. 1 and 4 on the circumference of the inner circle and at the positions of nozzles No. 14, 18, 22, and 24 on the circumference of the outer circle. Regarding the outer circle, the positional relationship between nozzle No. 18 and nozzle No. 24 is a point-symmetric positional relationship with the center of the furnace bottom 110 as the center of symmetry. Further, the bottom-blow tuyere facility of Comparative Example 4 is configured identically to the bottom-blow tuyere facility of Comparative Example 11. Comparative Example 4 and Comparative Example 11 have the same arrangement of the bottom-blow tuyeres 103 but different water amounts and water heights. As shown in Table 4, Comparative Example 4 has a maximum acceleration of 218 μm / s 2 and an eccentricity O of 0.81. Comparative Example 11 has a maximum acceleration of 214 μm / s 2 and an eccentricity O of 0.99.

[0062] In the bottom-blow tuyere facility of Comparative Example 5, the bottom-blow tuyeres 103 are provided at the positions of nozzles No. 1, 4, and 10 on the circumference of the inner circle and at the positions of nozzles No. 20, 21, and 24 on the circumference of the outer circle. Regarding the inner circle, the positional relationship between nozzle No. 4 and nozzle No. 10 is a point-symmetric positional relationship with the center of the furnace bottom 110 as the center of symmetry. Further, the bottom-blow tuyere facility of Comparative Example 5 is configured identically to the bottom-blow tuyere facility of Comparative Example 12. Comparative Example 5 and Comparative Example 12 have the same arrangement of the bottom-blow tuyeres 103 but different water amounts and water heights. As shown in Table 4, Comparative Example 5 has a maximum acceleration of 203 μm / s 2 and an eccentricity O of 0.61. Comparative Example 12 has a maximum acceleration of 193 μm / s 2 and an eccentricity O of 0.74.

[0063] In the bottom-blow tuyere facility of Comparative Example 6, the bottom-blow tuyeres 103 are provided at the positions of nozzles No. 7 and 9 on the circumference of the inner circle and at the positions of nozzles No. 18, 20, 21, and 23 on the circumference of the outer circle. Further, the bottom-blow tuyere facility of Comparative Example 6 is configured identically to the bottom-blow tuyere facility of Comparative Example 13. Comparative Example 6 and Comparative Example 13 have the same arrangement of the bottom-blow tuyeres 103 but different water amounts and water heights. As shown in Table 4, Comparative Example 6 has a maximum acceleration of 371 μm / s 2and the eccentricity O is 1.49. Comparative Example 13 has a maximum acceleration of 432 μm / s 2 and the eccentricity O is 1.81.

[0064] In the bottom blowing tuyere facility of Comparative Example 7, the bottom blowing tuyere 103 is provided at the positions of nozzles No. 5 and 10 on the circumference of the inner circle and at the positions of nozzles No. 17, 19, 21, and 24 on the circumference of the outer circle. As shown in Table 4, Comparative Example 7 has a maximum acceleration of 212 μm / s 2 and the eccentricity O is 0.70.

[0065] In the bottom blowing tuyere facility of Comparative Example 14, the bottom blowing tuyere 103 is provided at the positions of nozzles No. 3 and 5 on the circumference of the inner circle and at the positions of nozzles No. 13, 15, 18, 20, 21, and 24 on the circumference of the outer circle. As shown in Table 4, Comparative Example 14 has a maximum acceleration of 197 μm / s 2 and the eccentricity O is 0.67.

[0066] In the bottom blowing tuyere facility of Comparative Example 15, the bottom blowing tuyere 103 is provided at the positions of nozzles No. 8 and 10 on the circumference of the inner circle and at the positions of nozzles No. 14, 18, 20, 22, 23, and 24 on the circumference of the outer circle. Regarding the outer circle, the positional relationship between nozzle No. 14 and nozzle No. 20 and the positional relationship between nozzle No. 18 and nozzle No. 24 are in a point-symmetric positional relationship with the center of the furnace bottom 110 as the center of symmetry. As shown in Table 4, Comparative Example 15 has a maximum acceleration of 255 μm / s 2 and the eccentricity O is 1.16.

[0067] Figure 7 is a diagram showing the relationship between the eccentricity and the measured maximum acceleration. In Figure 7, the relationship between the eccentricity O and the maximum acceleration in Invention Examples 1 to 15 and the relationship between the eccentricity O and the maximum acceleration in Comparative Examples 1 to 15 are shown. As shown in Table 4, the eccentricity O of Invention Examples 1 to 15 is included in the range of 0.00 to 0.55. The eccentricity O of Comparative Examples 1 to 15 is included in the range of 0.61 to 1.85 as shown in Table 4.

[0068] As shown in Fig. 7, when the eccentricity O is less than 0.6, the maximum acceleration remains small, but when the eccentricity O exceeds 0.6, the maximum acceleration increases rapidly. That is, by arranging the bottom blowing tuyere 9 on the furnace bottom 8 so that the eccentricity O in the top-bottom blown converter 1 is less than 0.6, the occurrence of sloshing in the refining process can be suppressed.

[0069] Fig. 8 is a diagram showing the relationship between the eccentricity and the measured uniform mixing time. Fig. 8 shows the relationship between the eccentricity O and the uniform mixing time in Invention Examples 1 to 15 and the relationship between the eccentricity O and the uniform mixing time in Comparative Examples 1 to 15. The eccentricity O of Invention Examples 1 to 15 is included in the range of 0.00 to 0.55 as shown in Table 4. The eccentricity O of Comparative Examples 1 to 15 is included in the range of 0.61 to 1.85 as shown in Table 4.

[0070] As shown in Fig. 8, when the eccentricity O is 0.2 or more, the uniform mixing time remains small, but when the eccentricity O is less than 0.2, the uniform mixing time increases and the stirring force decreases significantly. That is, by arranging the bottom blowing tuyere 9 on the furnace bottom 8 so that the eccentricity O in the top-bottom blown converter 1 is 0.2 or more, the occurrence of sloshing in the refining process can be suppressed.

[0071] From the experimental results, it is possible to achieve both ensuring the stirring force and suppressing sloshing by setting the eccentricity O to 0.2 or more and less than 0.6. The top-bottom blown converter 1 is configured to satisfy that the eccentricity O is less than 0.6 in order to suppress the occurrence of sloshing in the refining process. Moreover, it is desirable that the top-bottom blown converter 1 satisfies that the eccentricity O is 0.2 or more in order to ensure a greater stirring force. That is, if the eccentricity O is less than 0.6, it is possible to achieve both ensuring the stirring force and suppressing sloshing while ensuring the stirring ability. And if the eccentricity O is 0.2 or more and less than 0.6, it is possible to achieve both ensuring the stirring force and suppressing sloshing while the stirring ability is improved.

[0072] In addition, although the refining method in which the eccentricity O is less than 0.6 has been described as an example applied to the top-bottom blown converter 1 in which the bottom blowing tuyeres 9 are dispersedly arranged at the furnace bottom, it is not limited thereto. This refining method may be a converter in which a plurality of gas discharge tuyeres are provided at the bottom of the refining vessel, and is also applicable to a bottom blown converter which does not include the top blowing lance 2.

[0073] Also, in this description, the center of the bottom of the furnace body 3 has been described as the furnace bottom center, but it is possible to describe the center of the bottom of the refining vessel as the bottom center.

Explanation of Signs

[0074] 1 Top-bottom blown converter 2 Top blowing lance 3 Furnace body 4 Trunion axis 5 Base 6 Slag 7 Hot metal 8 Furnace bottom 9 Bottom blowing tuyere (gas discharge port) 10 Molten metal

Claims

1. A refining method in which gas is blown into a refining vessel from a plurality of gas ejection tuyeres arranged at the bottom of the refining vessel, characterized in that the eccentricity O represented by the following formula (1) is less than 0.6 This is a refining method characterized by the above. 【Number 1】 However, in Formula (1), n is the number of bottom tuyeres, H is the height [m] of the molten metal in the refining vessel, r ｉ is the vector [m] from the center of the bottom to tuyere i in the horizontal cross-section of the refining vessel, R ｉ is the distance [m] from the center of the bottom to tuyere i in the horizontal cross-section of the refining vessel.

2. The eccentricity O represented by the formula (1) is 0.2 or more and less than 0.6 The refining method according to claim 1, characterized by the above.

3. The refining vessel is used in a converter equipped with a function of blowing oxygen from an upper blowing lance The refining method according to claim 2, characterized by the above.

4. A converter comprising a plurality of gas ejection tuyeres arranged at the bottom of a refining vessel and configured to blow gas into the refining vessel from the plurality of gas ejection tuyeres, characterized in that the gas ejection tuyeres are arranged at the bottom of the refining vessel such that the eccentricity O represented by the following formula (2) is less than 0.6 This is a converter characterized by the above. 【Number 2】 However, in Formula (2), n is the number of bottom tuyeres, H is the height [m] of the molten metal in the refining vessel, r ｉ is the vector [m] from the center of the bottom in the horizontal cross-section of the refining vessel to tuyere i, R ｉ is the distance [m] from the center of the bottom in the horizontal cross-section of the refining vessel to tuyere i.

5. The eccentricity represented by the formula (2) is 0.2 or more and less than 0.6 The converter according to claim 4, characterized by the above.

6. An upper blowing lance for blowing oxygen into the inside of the refining vessel is provided The converter according to claim 5, characterized by the above.

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