A bottom-blowing gas spouting brick for ladle refining and a method for refining using the same

Abstract

The present application relates to the technical field of steel metallurgy, in particular to a bottom-blowing gas-permeable brick for ladle refining and a refining method using the same, wherein the round-hole gas passages are arranged in rows and regularly distributed with the slit gas passages, the processing is simple, the material is saved, the argon gas has different bubble shapes after entering the molten steel through the bottom-blowing gas-permeable brick, and is not easy to gather, the utilization efficiency of the bottom-blowing gas is improved, the stirring effect on the molten steel is enhanced, the inclusions of various particle sizes are beneficial to be removed, the temperature and composition are uniform, and thus some steel grades with high requirements for inclusion control and element content can be better produced, and the refining efficiency is improved. Moreover, the arrangement mode of the bottom-blowing gas-permeable brick in the ladle is more beneficial to the stability of the airflow, the scouring to the ladle wall can be reduced, and the service life of the ladle is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of steel metallurgy, in particular to a bottom-blowing gas permeation brick for ladle refining and a refining method using the same. BACKGROUND

[0002] Ladle bottom-blowing argon can homogenize the temperature and composition of the molten steel and promote the floating of inclusions, and is an effective means of molten steel refining. The effect of argon blowing directly affects the effect of ladle refining and the subsequent production rhythm, and is an important part of the entire steelmaking process. The type, number and relative position of the gas permeation brick determine the distribution of the flow field in the ladle and the utilization rate of the stirring energy, which are important factors affecting the argon blowing effect. Design and optimization of the argon blowing parameters of the ladle according to the specific equipment conditions and production process of the steel plant can improve the heat and mass transfer in the ladle, promote the steel-slag interface reaction, and effectively improve the purification effect of the molten steel.

[0003] The main dispersion type gas permeation brick is used in the production at present. The dispersion type gas permeation brick can well remove inclusions, has good anti-permeability, produces a large number of uniform bubbles during use, has good refining effect, and avoids the step of blowing oxygen to clean up after each smelting is completed, so that the use performance is effectively improved. The gas permeation bricks used in production also include slit type gas permeation bricks and straight-through directional type gas permeation bricks, but they do not have the advantages of dispersion type gas permeation bricks, so the use amount is not large. However, the dispersion type gas permeation brick also has some unavoidable problems during use, such as difficulty in controlling air holes, strong bubble aggregation, poor air flow stability, low brick body strength, etc., which greatly reduces the service life of the gas permeation brick. Moreover, the removal of inclusions during argon blowing is closely related to the size of the bubbles in the molten steel, and different sizes of bubbles have different capture rates for inclusions of the same particle size. At the same time, the lowermost part of the gas permeation brick used at present has only one gas passage, and only one kind of gas can be introduced at a time. If other gases are introduced into the ladle at the same time, additional devices need to be set, which increases the production cost. SUMMARY

[0004] The main purpose of the present application is to provide a bottom-blowing gas permeation brick for ladle refining and a refining method using the same, which aims to solve the problems of the prior art bottom-blowing gas permeation brick.

[0005] To solve the above technical problems, according to one aspect of the present application, the present application provides the following technical scheme:

[0006] A bottom-blowing gas permeation brick for ladle refining, comprising a gas permeation brick body, a gas passage and a gas inlet pipe;

[0007] The gas permeation brick body is in the shape of a circular truncated cone, and the gas passage penetrates the gas permeation brick body along the vertical direction;

[0008] The gas passage includes slit gas passages and round-hole gas passages, which are respectively distributed on the two semicircular tables of the gas passage body.

[0009] As a preferred scheme of the bottom-blowing gas passage brick for ladle refining, in the scheme, the longitudinal section of the slit gas passage along the length direction is isosceles trapezoidal, the inner angle between the side of the isosceles trapezoid and the short side is 91-93°; the longitudinal section of the slit gas passage along the width direction is rectangular; the width of the slit is 1.6-2.0 mm, the length of the slit on the top surface of the gas passage body is 38-40% of the radius of the top surface of the gas passage body and is located at the middle position of the radius; the number of the slit gas passages is 15-18, and the slit gas passages are respectively and uniformly distributed along the radial direction on one side of the semicircular table of the gas passage body.

[0010] As a preferred scheme of the bottom-blowing gas passage brick for ladle refining, in the scheme, the round-hole gas passage is in the hollow semicircular table structure of large at the top and small at the bottom, the angle between the side of the round-hole gas passage and the vertical direction is 1-3°; the diameter of the round hole on the top surface of the gas passage body is 1.6-2.0 mm; n round-hole gas passages form a column, n≥2, the distance between the centers of the two round holes at the two ends of each column on the top surface of the gas passage body is 36-38% of the radius of the top surface of the gas passage body and is located at the middle position of the radius; 15-18 columns of round-hole gas passages are arranged, and the round-hole gas passages in each column are respectively and uniformly distributed along the radial direction on one side of the semicircular table of the gas passage body.

[0011] As a preferred scheme of the bottom-blowing gas passage brick for ladle refining, in the scheme, the radius of the bottom surface of the gas passage body is 1.6-2 times of the radius of the top surface; the height of the gas passage body is 460-480 mm.

[0012] As a preferred scheme of the bottom-blowing gas passage brick for ladle refining, in the scheme, the number of the slit gas passages is equal to the number of the columns of the round-hole gas passages.

[0013] As a preferred scheme of the bottom-blowing gas passage brick for ladle refining, in the scheme, the lower end of each slit gas passage and round-hole gas passage is independently connected with a gas inlet pipe, and the gas inlet pipes of the slit gas passages and the gas inlet pipes of the round-hole gas passages are respectively gathered in one gas passage pipe, and the gas passage pipe is in the shape of umbrella rib.

[0014] To solve the above technical problems, according to another aspect of the present application, the present application provides the following technical scheme:

[0015] A method for ladle refining, comprising the following steps:

[0016] S1, installing the bottom-blowing gas passage brick on the bottom of the ladle;

[0017] S2, different types of gas are blown into the molten steel through the bottom blowing gas brick to realize ladle refining.

[0018] As a preferred scheme of the method for ladle refining, in the step S1, two bottom blowing gas bricks are installed at the bottom of the ladle, the center angle of the two bottom blowing gas bricks is 135°, the distance from one of the bottom blowing gas bricks to the center of the bottom of the ladle is 0.3R, the distance from the other bottom blowing gas brick to the center of the bottom of the ladle is 0.5R, and R is the radius of the bottom of the ladle.

[0019] The beneficial effects of the present application are as follows:

[0020] The bottom blowing gas brick for ladle refining and the method for refining by using the same provided by the present application arrange the circular hole gas passages in a row and regularly distribute the slit gas passages, which is simple to process and saves materials. After argon passes through the bottom blowing gas brick into the molten steel, different bubble shapes are formed, and the bubbles are not easy to gather, which improves the utilization efficiency of the bottom blowing gas, enhances the stirring effect on the molten steel, is beneficial to remove inclusions of various particle sizes, and uniformly temperature and composition, so that some steel grades with high requirements for inclusion control and element content can be better produced, and the refining efficiency is improved. Moreover, the arrangement mode of the bottom blowing gas brick in the ladle can change the gas type and gas amount corresponding to each passage, which is more conducive to the stability of the gas flow, can reduce the scouring of the ladle wall, and improves the service life of the ladle. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description only show some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort based on the drawings shown.

[0022] Figure 1 It is a top view of the bottom blowing gas brick of the present application.

[0023] Figure 2 It is a structural schematic view of the bottom blowing gas brick of the present application.

[0024] Figure 3 It is a comparison chart of mixing time of the bottom blowing gas brick and the diffusive gas brick of the present application.

[0025] Figure 4 It is a comparison chart of inclusion removal rate of the bottom blowing gas brick and the diffusive gas brick of the present application.

[0026] Figure 5 It is a comparison chart of the bubbles generated by the bottom blowing gas brick and the diffusive gas brick of the present application.

[0027] Among them, 1-slit, 2-round hole, 3-slit gas channel, 4-round hole gas channel, 5-permeable brick body, 6-ventilation pipe, 7-umbrella shape.

[0028] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0029] The technical solutions described below in conjunction with the embodiments will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] According to one aspect of the present invention, the present invention provides the following technical solution:

[0031] like Figures 1-2 As shown, a bottom-blown permeable brick for ladle refining includes a permeable brick body 5, a gas channel, and an air inlet pipe.

[0032] The breathable brick body 5 is frustum-shaped, and a gas channel that runs vertically through the top and bottom surfaces of the breathable brick body 5 is provided. The air inlet pipe is connected to the gas channel opening on the bottom surface of the breathable brick body 5.

[0033] The gas channels include a slit gas channel 3 and a circular hole gas channel 4, which are respectively distributed on the two semicircular platforms of the permeable brick body 5.

[0034] Preferably, the longitudinal cross-section of the slit gas channel 3 along its length is an isosceles trapezoid, and the included angle between the side and the short side of the isosceles trapezoid is 91°-93°; the longitudinal cross-section of the slit gas channel 3 along its width is rectangular; the width of the slit 1 is 1.6-2.0 mm, and the length of the slit on the top surface of the permeable brick body 5 is 38-40% of the radius of the top surface of the permeable brick body 5, and is located at the middle of the radius; the number of slit gas channels 3 is 15-18, and the slit gas channels 3 are evenly distributed along the radial direction on one side of the semicircular platform of the permeable brick body 5.

[0035] Preferably, the circular hole gas passage 4 is in the form of a hollow circular truncated cone structure with a large top and a small bottom, and the angle between the side of the circular hole gas passage 4 and the vertical direction is 1°-3°; the diameter of the circular hole 2 on the top surface of the gas permeable brick body 5 is 1.6-2.0 mm; the n circular hole gas passages 4 are arranged in a row, and n≥2; the distance between the centers of the two circular holes 2 at the ends of each row on the top surface of the gas permeable brick body 5 is 36-38% of the radius of the top surface of the gas permeable brick body 5, and is located at the middle position of the radius; the circular hole gas passages 4 are arranged in 15-18 rows, and each row of circular hole gas passages 4 is uniformly distributed along the radial direction on one side of the half circular truncated cone of the gas permeable brick body 5.

[0036] Preferably, the radius of the bottom surface of the gas permeable brick body 5 is 1.6-2 times the radius of the top surface; and the height of the gas permeable brick body 5 is 460-480 mm.

[0037] Preferably, the number of the slit gas passages 3 is equal to the number of rows of the circular hole gas passages 4.

[0038] Preferably, the lower end of each slit gas passage 3 and circular hole gas passage 4 is independently connected with a gas inlet pipe, and the gas inlet pipes of the slit gas passages and the gas inlet pipes of the circular hole gas passages are respectively gathered into one gas passage pipe 6, and the connection of the gas passage pipes is in the form of an umbrella rib 7.

[0039] According to another aspect of the present application, the present application provides the following technical solutions:

[0040] A method for ladle refining, comprising the following steps:

[0041] S1, installing the bottom blowing gas permeable brick described above at the bottom of the ladle;

[0042] S2, blowing different types of gas into the molten steel through the bottom blowing gas permeable brick to realize the ladle refining.

[0043] Preferably, in the step S1, two bottom blowing gas permeable bricks described above are installed at the bottom of the ladle, and the center angle between the two bottom blowing gas permeable bricks is 135°, one of the two bottom blowing gas permeable bricks is located at a distance of 0.3R from the center of the bottom of the ladle, and the other bottom blowing gas permeable brick is located at a distance of 0.5R from the center of the bottom of the ladle, and R is the radius of the bottom of the ladle.

[0044] The technical solutions of the present application are further described below in combination with specific embodiments.

[0045] The technical scheme of the application is simulated by physical simulation, the bottom blowing gas permeable bricks and the ladle are reduced according to the geometric similarity ratio of 1:4.4 on the basis of the size of the bottom blowing gas permeable bricks and the ladle used in actual production, and are made of organic glass; the top surface of the bottom blowing gas permeable brick is half of a slit and half of a circular hole, three of the circular holes are in one column, the included angle of each column is 12°, there are 15 slits in total and 15 columns of circular holes; the diameter of the bottom surface of the gas permeable brick is 50mm, and the diameter of the top surface is 31mm; the longitudinal section of the slit gas channel along the length direction is an isosceles trapezoid, the included angle between the side of the isosceles trapezoid and the short side is 91°; the longitudinal section of the slit gas channel along the width direction is a rectangle; the length of each slit is 6mm, the width is 0.4mm, and the slit is located at the middle position of the radius; the slit gas channels are uniformly distributed on one side of the half circular table of the gas permeable brick body along the radial direction. The circular hole gas channel is a hollow circular table structure with the top being large and the bottom being small, the included angle between the side of the circular hole gas channel and the vertical direction is 1°; the diameter of each circular hole on the top surface of the gas permeable brick body is 0.4mm; the distance between the centers of the two circular holes at the two ends of each column on the top surface of the gas permeable brick body is 5.6mm, and the two circular holes are located at the middle position of the radius; each column of circular hole gas channels is uniformly distributed on one side of the half circular table of the gas permeable brick body along the radial direction. The height of the gas permeable brick body 5 is set to 105mm. The lower end of each slit gas channel and circular hole gas channel is independently connected with a gas inlet pipe, and the gas inlet pipes of the slit gas channels and the circular hole gas channels are respectively collected in one pipe, which presents an umbrella type.

[0046] Two bottom blowing gas permeable bricks are installed at the bottom of the ladle, the included angle between the centers of the two bottom blowing gas permeable bricks is 135°, one of the bottom blowing gas permeable bricks is 0.3R away from the center of the bottom of the ladle, and the other bottom blowing gas permeable brick is 0.5R away from the center of the bottom of the ladle, R is the radius of the bottom of the ladle. The diameter of the bottom of the ladle is 650mm, the diameter of the upper opening of the ladle is 760mm, and the height is 900mm.

[0047] According to the similarity theory, the calculation process of the bottom blowing flow rate is as follows:

[0048]

[0049] Fr m ′=Fr p ′ (2)

[0050]

[0051]

[0052]

[0053]

[0054] In the formula, Fr′ is the modified Froude number, dm Diameter of the gas permeable brick used for the model, 31 mm, d p Diameter of the gas permeable brick used in the production site, 140 mm, H m Height of the liquid surface in the ladle model, 602 mm, H p Depth of the molten steel bath in the ladle in the production site, 2650 mm, T m Room temperature, 298 K, T p Temperature of the molten steel, 1873 K, P atm Standard atmospheric pressure, 1.0313 x 10 5 pa, p l，p Density of the molten steel at standard state, 7000 kg / m 3 ; p l，m Density of water at standard state, 1000 kg / m 3 ; p g，p Density of argon at standard state, 1.784 kg / m 3 ; p g，m Density of air at standard state, 1.29 kg / m 3 ; g is a constant, 9.8 m / s 2 , Q m is the flow rate of the gas blown through the gas permeable brick in the model, Q p is the flow rate of the gas blown through the gas permeable brick in the production site, Q A is the indicated value of the flow meter, Q real is the flow rate of the high temperature gas.

[0055] The relationship between the gas flow at the inlet of the model and the prototype is shown in equations (9) - (10):

[0056] Q m = 0.01576 Q real (7)

[0057] Q A = 0.0185 Q real (8)

[0058] In the case of 300 L / min in the production site, the calculated gas flow rate for the bottom blowing in the water model experiment is 5.6 L / min. The gas pump is turned on and the flow meter is adjusted to show 5.6 L / min. The ladle has double gas permeable bricks at the bottom, each of which has two gas pipes, for a total of four pipes. Each pipe has a gas flow rate of 1.4 L / min, and the gas type is air. After the flow field in the ladle model is stabilized, KCl is added to determine the mixing time Figure 3 ), the bubble shape blown by the different bottom blowing gas permeable bricks is observed Figure 5 ), and numerical simulation is used to simulate the removal of inclusions Figure 4 .

[0059] Figure 3The diagram shows a comparison of the mixing time of the bottom-blown permeable brick and the dispersion permeable brick of the present invention. It can be seen that the mixing time of the bottom-blown permeable brick of the present invention is 12 seconds faster than that of the dispersion permeable brick. Figure 4 The graph shows a comparison of the inclusion removal rates of the bottom-blown permeable brick and the dispersion permeable brick of the present invention. It can be seen that under different particle sizes, the removal effect of the bottom-blown permeable brick of the present invention is better than that of the dispersion permeable brick. Specifically, the removal rate of 5μm is increased by 2.4%, the removal rate of 20μm is increased by 3.3%, and the removal rate of 100μm is increased by 2.5%. Figure 5 The bottom-blown permeable brick of the present invention ( Figure 5 (middle left image) and diffused permeable bricks ( Figure 5 The comparison diagram of the bubbles produced (right side of the middle figure) clearly shows that when using the bottom-blown permeable brick of the present invention, the bubbles are more dispersed and the airflow is more stable, and different shapes of bubbles are produced. In contrast, the bubbles produced by the diffuse permeable brick have a single shape, a high degree of aggregation, and the airflow deviates to a certain extent.

[0060] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A bottom-blowing gas-lancing brick for ladle refining, characterized in that, The air brick body, the gas passage and the gas inlet pipe are included. The air brick body is in the shape of a circular truncated cone, and the gas passage is arranged through the air brick body along the vertical direction. The gas passage includes slit gas passages and circular hole gas passages, which are arranged on the two semicircular truncated cones of the air brick body. The slit gas passage is in the shape of an isosceles trapezoid along the length direction, and is in the shape of a rectangle along the width direction. The slit is located at the middle position of the radius.

2. The bottom-blowing gas-lancing brick for a ladle refining according to claim 1, characterized by, The inner angle between the side and the short side of the isosceles trapezoid is 91-93°, the width of the slit is 1.6-2.0 mm, the length of the slit on the top surface of the air brick body is 38-40% of the radius of the top surface of the air brick body, the number of the slit gas passages is 15-18, and the slit gas passages are evenly distributed along the radius direction on one side of the air brick body.

3. The bottom-blowing gas-lancing brick for a ladle refining according to claim 1, characterized by, The circular hole gas passage is in the shape of a hollow circular truncated cone with the top larger than the bottom.

4. A method of ladle refining, characterized by The n circular hole gas passages are arranged in a row, n≥2, and are located at the middle position of the radius. The angle between the side of the circular hole gas passage and the vertical direction is 1-3°. The diameter of the circular hole on the top surface of the air brick body is 1.6-2.0 mm.

5. The method of ladle refining according to claim 4, characterized in that The distance between the centers of the two circular holes at the two ends of each row on the top surface of the air brick body is 36-38% of the radius of the top surface of the air brick body. The number of the slit gas passages is equal to the number of the rows of the circular hole gas passages. Each slit gas passage and circular hole gas passage is independently connected with a gas inlet pipe at the lower end. The method comprises the following steps: S1, installing the bottom blowing air brick of any one of claims 1-3 at the bottom of the ladle; S2, blowing different types of gas into the molten steel through the bottom blowing air brick to realize the refining of the ladle. In the step S1, two bottom blowing air bricks are installed at the bottom of the ladle. The center angle between the two bottom blowing air bricks is 135°. One of the two bottom blowing air bricks is located at a distance of 0.3R from the center of the bottom of the ladle, and the other is located at a distance of 0.5R from the center of the bottom of the ladle. R is the radius of the bottom of the ladle.

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