阅读说明：本技术 一种顶底复吹转炉及炼钢方法 (Top-bottom combined blown converter and steelmaking method ) 是由 陈敏 铉明涛 王楠 徐磊 陈兴华 李家通 胡志勇 陈鹏涛 于 2020-11-23 设计创作，主要内容包括：本发明公开了一种顶底复吹转炉及炼钢方法,其中,顶底复吹转炉包括：炉体,包括炉壁、与所述炉壁底部连接的炉底以及与所述炉底相连接的座砖；吹气组件,包括设在所述炉底上的至少4个底吹元件,所述底吹元件的轴线相对于所述炉壁轴线的平行线方向倾斜设置,使所述炉体内的液体在从所述底吹元件吹入到所述炉体内的气体的带动下形成水平环流和上下环流。本发明提供的顶底复吹转炉通过将底吹元件的轴线相对于炉壁的轴线方向倾斜设置,可有使从底吹元件进入的气体进入炉体后不仅沿垂直方向运动,而且也沿水平方向对液体进行搅拌,进而转炉在液体内形成了整体大环流,减弱熔池内各搅拌子区域间的相互干扰,有利于改善炉体内液体的搅拌效果。(The invention discloses a top-bottom combined blown converter and a steelmaking method, wherein the top-bottom combined blown converter comprises: the furnace body comprises a furnace wall, a furnace bottom connected with the bottom of the furnace wall and a brick cup connected with the furnace bottom; and the blowing assembly comprises at least 4 bottom blowing elements arranged on the furnace bottom, and the axes of the bottom blowing elements are obliquely arranged relative to the direction parallel to the axis of the furnace wall, so that liquid in the furnace body forms horizontal circulation and up-and-down circulation under the driving of gas blown into the furnace body from the bottom blowing elements. The top-bottom combined blown converter provided by the invention has the advantages that the axis of the bottom blowing element is obliquely arranged relative to the axis direction of the converter wall, so that the gas entering from the bottom blowing element can not only move along the vertical direction after entering the converter body, but also stir the liquid along the horizontal direction, further the converter forms an integral large circulation in the liquid, the mutual interference among all stirring sub-areas in the molten pool is weakened, and the stirring effect of the liquid in the converter body is favorably improved.)

1. A top-bottom combined blown converter, comprising:

the furnace body comprises a furnace wall (1), a furnace bottom (2) connected with the bottom of the furnace wall (1) and a brick cup connected with the furnace bottom (1);

the blowing assembly comprises at least 4 bottom blowing elements (3) arranged on the furnace bottom (2), the axes of the bottom blowing elements (3) are obliquely arranged relative to the direction parallel to the axis of the furnace wall (1), so that liquid in the furnace body forms horizontal circulation and up-and-down circulation under the driving of gas blown into the furnace body from the bottom blowing elements (3).

2. A top-bottom combined blown converter according to claim 1, characterized in that said bottom blowing element (3) comprises:

the air inlet (301) is arranged on the lower surface of the furnace bottom (2) and is used for being connected with an air supply assembly;

the gas outlet (302) is arranged on the upper surface of the furnace bottom (2) and is communicated with the inner cavity of the furnace body;

the gas channel (303) is arranged in the bottom blowing element (3) and is parallel to the axial direction of the bottom blowing element (3), and the gas channel (303) is respectively connected with the gas inlet (301) and the gas outlet (302);

wherein, the gas supplied to the bottom blowing element (3) by the gas supply assembly is a mixed gas of one or more gases of nitrogen, argon, carbon dioxide, water vapor and natural gas.

3. A top-bottom combined blown converter according to claim 2, characterized in that the angle between the axis of the bottom blowing element (3) and the parallel to the axis of the furnace wall (1) is between 5 ° and 60 °.

4. A top-bottom combined blown converter according to claim 3, wherein the outlet openings (302) of all the bottom blowing elements (3) are arranged on the same circumference centered on the center of the furnace bottom (2).

5. A top-bottom combined blown converter according to claim 4, characterized in that the air outlets (302) of all said bottom blowing elements (3) are arranged uniformly on the same circumference centered on the center of said bottom (2); or

The air outlets (302) of all the bottom blowing elements (3) are non-uniformly arranged on the same circumference which takes the center of the furnace bottom (2) as the center of a circle.

6. A top-bottom combined blown converter according to claim 3, wherein said outlet openings (302) of all said bottom blowing elements (3) are respectively arranged on 2-5 concentric circles of different radii centered on the center of said furnace bottom (2).

7. A top-bottom combined blown converter according to claim 6, wherein the outlet openings (302) of said bottom blowing elements (3) located on the circumference of a concentric circle are evenly arranged on this circumference; and/or the air outlets (302) of the bottom-blowing elements (3) are arranged non-uniformly over the circumference of a concentric circle.

8. A top-bottom combined blown converter according to claim 6, wherein the outlet openings (302) of said bottom blowing elements (3) located on concentric circles of different radii are arranged uniformly on concentric circles of different radii; and/or

The air outlets (302) on the bottom blowing element (3) on the concentric circles with different radiuses are arranged non-uniformly on the concentric circles with different radiuses.

9. A molten steel refining apparatus according to any one of claims 1 to 8, characterized in that the ladle wall (1), the ladle bottom (2), the bottom-blowing element (3) and the brick cup (4) are made of one or both of refractory and metal.

10. A method of producing steel, characterized in that stirring of molten steel in the furnace body is carried out by blowing gas into the furnace body from a bottom-blowing element (3) on a top-bottom combined blown converter according to any one of claims 1 to 9.

11. Steelmaking method according to claim 10, characterised in that the gas supply assembly to which the bottom-blowing elements (3) are connected has a gas supply pressure of 0.7-3.0 MPa.

Technical Field

The invention belongs to the technical field of ferrous metallurgy, and particularly relates to a top-bottom combined blown converter and a steelmaking method.

Background

In the process of steelmaking of a top-bottom combined blown converter, oxygen is blown into a molten pool through an oxygen lance to oxidize elements such as carbon, silicon, manganese, phosphorus and the like in molten steel, and inert gas is blown at the bottom to enhance stirring in the molten pool, so that the aims of increasing the temperature of the molten steel, removing the content of harmful elements such as phosphorus, sulfur and the like and adjusting the content of carbon, silicon, manganese and the like in the molten steel are fulfilled. The top-bottom combined blowing converter has the advantages of high reaction rate, high heat efficiency, high slag melting speed, strong dephosphorization, easy decarburization, stable blowing, easy control of end point and the like, and becomes a widely applied steelmaking method.

In the blowing process of a top-bottom combined blown converter, the liquid of a converter molten pool is driven by the gas blown in by a top lance and a bottom blowing element to form up-down circular flow for stirring the molten pool, and a plurality of stirring subareas are formed above the bottom blowing element in the molten pool.

In recent years, with the progress of iron-making technology, the production efficiency of blast furnaces is gradually improved; meanwhile, the rapid development of the continuous casting technology enables the steel passing amount of the casting machine to be greatly improved. The improvement of the two aspects puts forward higher requirements on the converter steelmaking cycle, namely the components and the temperature of the molten steel meet the smelting requirements in a shorter smelting cycle. On the other hand, along with the rapid development of society, the requirements on the quality of steel products are increasingly improved, and more strict requirements on the cleanliness of molten steel are provided. In addition, the steel industry is increasingly competitive, which puts some pressure on the cost of the steel production process. Therefore, the improvement of the production efficiency and the quality of the molten steel of the converter and the reduction of the production cost become common problems of converter smelting technology, the reduction of the blowing time can not only effectively reduce the usage amount of oxygen, but also reduce the carbon-oxygen product of the molten steel at the end point, and further reduce the usage amount of alloy and the content of oxide inclusions in the molten steel, which is in accordance with the current development route of the steel industry with high quality, high efficiency, environmental protection and low cost. Therefore, the development of a novel high-efficiency converter steelmaking technology has important economic and social benefits.

The patent application with the application number of 201210467199.X discloses a method for applying a swirl oxygen lance to vanadium extraction of a converter and the swirl oxygen lance, wherein oxygen jet flow is jetted to the liquid surface of a molten pool of the converter through the swirl oxygen lance, and horizontal shearing force is caused to the liquid surface to cause horizontal circulation between the liquid surface and the interior of the molten pool, but horizontal stirring of the method is rapidly dissipated mainly in the process of transferring the horizontal stirring to the interior of the molten pool through the liquid surface, so that the method has limited effect; the patent application with the application number of 200810126344.1 discloses a top-bottom side-blown converter steelmaking method, which is characterized in that a spray gun is arranged on the wall of a converter to horizontally stir a molten pool in the converter on the basis of a conventional top-bottom combined blown converter, but the method not only can accelerate the erosion of refractory bricks on the wall of the converter, but also can increase the complexity of equipment to obviously improve the cost, and in addition, the side blowing also stirs the middle upper part of an upper molten pool, so that the effect on the lower part of the molten pool is limited; patent application No. 95213362.8 discloses an oxygen side blown converter, but it is only suitable for small and medium sized converters, not for modern large converters. Meanwhile, the side blown converter has frequent furnace shaking operation, which is not beneficial to the installation of dust removing equipment, so the pollution is serious and the development trend of environmental protection is not met. The patent application with the application number of 200820076946.6 discloses an asymmetric arrangement of bottom-blowing gas permeable elements suitable for medium-sized converters, but the asymmetric arrangement of bottom-blowing gas permeable elements is only suitable for medium-sized converters because the number of bottom-blowing gas permeable elements of a large-sized converter is large and the asymmetric arrangement of bottom-blowing gas permeable elements is not required to be adopted.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a top-bottom combined blown converter and a steelmaking method.

In one aspect, the present invention provides a top-bottom combined blown converter, including:

the furnace body comprises a furnace wall, a furnace bottom connected with the bottom of the furnace wall and a brick cup connected with the furnace bottom;

and the blowing assembly comprises at least 4 bottom blowing elements arranged on the furnace bottom, and the axes of the bottom blowing elements are obliquely arranged relative to the direction parallel to the axis of the furnace wall, so that liquid in the furnace body forms horizontal circulation and up-and-down circulation under the driving of gas blown into the furnace body from the bottom blowing elements.

Further, the bottom blowing element includes:

the air inlet is arranged on the lower surface of the furnace bottom and is used for being connected with an air supply assembly;

the gas outlet is arranged on the upper surface of the furnace bottom and communicated with the inner cavity of the furnace body;

the gas channel is arranged in the bottom blowing element and is parallel to the axial direction of the bottom blowing element, and the gas channel is respectively connected with the gas inlet and the gas outlet;

the gas supplied by the gas supply assembly to the bottom blowing element is one or a mixture of nitrogen, argon, carbon dioxide, water vapor and natural gas.

Further, the angle between the axis of the bottom blowing element and the parallel to the furnace wall axis is 5-60 °.

Furthermore, the air outlets of all the bottom blowing elements are arranged on the same circumference which takes the center of the furnace bottom as the center of a circle.

Further, air outlets on all the bottom blowing elements are uniformly arranged on the same circumference which takes the center of the furnace bottom as the circle center; or

The air outlets of all the bottom blowing elements are arranged non-uniformly on the same circumference which takes the center of the furnace bottom as the center of a circle.

Furthermore, air outlets of all the bottom blowing elements are respectively arranged on 2-5 concentric circles with different radiuses and taking the center of the furnace bottom as the center of a circle.

Further, the air outlets on the bottom blowing element on the circumference of a concentric circle are uniformly arranged on the circumference; and/or the air outlets of the bottom-blowing element are located on the circumference of a concentric circle and are arranged non-uniformly on this circumference.

Further, air outlets on the bottom blowing elements on the concentric circumferences with different radiuses are uniformly arranged on the concentric circumferences with different radiuses; and/or

The air outlets on the bottom blowing element on the concentric circumferences with different radiuses are arranged unevenly on the concentric circumferences with different radiuses.

Furthermore, the ladle wall, the ladle bottom, the bottom blowing element and the brick cup are all made of one or two of refractory materials and metal products.

In another aspect of the present invention, there is provided a steel making method in which gas is blown into the furnace body from a bottom-blowing element provided in the top-bottom combined blown converter as described above, thereby stirring molten steel in the furnace body.

Further, the air supply pressure of the air supply assembly connected with the bottom blowing element is 0.7-3.0 MPa.

The top-bottom combined blowing converter and the steelmaking method provided by the invention have the advantages that the axis of the bottom blowing element is obliquely arranged relative to the axis direction of the converter wall, so that the gas entering from the bottom blowing element can not only move along the vertical direction after entering the converter body, but also stir the liquid along the horizontal direction, further the converter forms an integral large circulation in the liquid, the mutual interference among all stirrer areas in the molten pool is weakened, the stirring effect of the liquid in the converter body is favorably improved, the reaction in the converter body is accelerated, the smelting effect is improved, and the smelting efficiency is improved. Meanwhile, the bottom blowing element arranged obliquely can reduce the air quantity required in the production process of the converter, reduce the foam slag and iron loss, reduce the carbon and oxygen content of the molten steel, and further achieve the purposes of improving the smelting efficiency and reducing the smelting cost.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

The technical solution of the present invention is further described in detail by the accompanying drawings and embodiments.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:

FIG. 1 is a schematic structural view of a top-bottom combined blown converter according to an exemplary embodiment of the present invention;

FIG. 2 is a top plan view of a top-bottom combined blown converter in accordance with an exemplary embodiment of the present invention;

FIG. 3 is a partial cross-sectional view taken at A-A of FIG. 2;

FIG. 4 is a schematic view of the upper surface structure of the air outlet of the exemplary embodiment of the present invention;

FIG. 5 is a schematic view showing the arrangement of air outlets in exemplary embodiment 2 of the present invention;

FIG. 6 is a schematic view showing the arrangement of air outlets in exemplary embodiment 3 of the present invention;

fig. 7 is a schematic view of the arrangement of the air outlets in exemplary embodiment 4 of the present invention.

In the figure:

1-a furnace wall;

2-furnace bottom;

3-bottom blowing element, 301-gas inlet, 302-gas outlet, 303-gas channel;

4-brick setting.

Detailed Description

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", and the like, indicate orientations and positional relationships based on those shown in the drawings, and are used only for convenience of description and simplicity of description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be considered as limiting the present invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.

In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

The preferred embodiments of the present invention will be described in conjunction with the accompanying drawings, and it will be understood that they are described herein for the purpose of illustration and explanation and not limitation.

The invention provides a top-bottom combined blown converter, which is shown in figure 1 and comprises a converter body and a blowing component, wherein the converter body comprises a converter wall 1, a converter bottom 2 connected with the bottom of the converter wall 1 and a brick cup 4 connected with the converter bottom; the blowing assembly comprises at least 4 bottom blowing elements 3 arranged on the furnace bottom 2, the bottom blowing elements 3 are arranged in brick holders 4, the axes of the bottom blowing elements 3 are obliquely arranged relative to the direction of the parallel line of the axes of the furnace wall 1, so that liquid in the furnace body forms horizontal circulation and up-and-down circulation under the driving of gas blown into the furnace body from the bottom blowing elements 3; preferably, the blowing assembly comprises 4-24 bottom blowing elements 3 arranged on the furnace bottom 2.

The invention provides a top-bottom combined blown converter, which is different from the traditional arrangement mode that the axis of a bottom blown element 3 points to the axis of a furnace body, and the axis of the bottom blown element 3 is obliquely arranged relative to the direction parallel to the axis of the furnace wall 1, so that gas entering from the bottom blown element 3 can move along the vertical direction and stir liquid along the horizontal direction after entering the furnace body, and then the liquid forms an integral large circulation in the converter, the mutual interference among all stirrer areas in a molten pool is weakened, the stirring effect of the liquid in the furnace body is favorably improved, the reaction in the furnace body is accelerated, the smelting effect is improved, and the smelting efficiency is improved. Meanwhile, the bottom blowing element 3 which is obliquely arranged can also reduce the air quantity required in the production process of the converter, reduce the foam slag and iron loss, reduce the carbon and oxygen content of the molten steel, and further achieve the purposes of improving the smelting efficiency and reducing the smelting cost.

As a preferred embodiment, the bottom blowing element 3 comprises an air inlet 301, an air outlet 302 and an air channel 303, the air inlet 301 being provided on the lower surface of the furnace bottom 2 for connection with an air supply assembly; the gas outlet 302 is arranged on the upper surface of the furnace bottom 2 and is communicated with the inner cavity of the furnace body; the gas channel 303 is arranged in the bottom blowing element 3 and is parallel to the axial direction of the bottom blowing element 3, and the gas channel 303 is respectively connected with the connecting gas inlet 301 and the gas outlet 302; wherein, the gas supplied to the bottom blowing element 3 by the gas supply assembly is a mixed gas of one or more of nitrogen, argon, carbon dioxide, water vapor and natural gas.

Preferably, referring to fig. 4, the gas channel 303 comprises a plurality of gas holes with the same diameter and uniformly distributed in the bottom-blowing element 3, and the axis of each gas hole is parallel to the axis of the bottom-blowing element 3, so that the gas flow rate is improved, and the gas entering from the gas inlet 301 can stably flow into the ladle in the preset direction by bubbles with uniform size, thereby improving the stirring efficiency of the gas on the molten steel.

Preferably, the angle between the axis of the bottom-blowing element 3 and the parallel to the axis of the furnace wall 1 is 5-60. In the embodiment, the included angle between the bottom blowing element 3 and the parallel line of the axis of the furnace wall 1 is 5-60 degrees, so that the gas blown into the molten steel from the gas outlet 302 can flow in the horizontal and vertical directions at the same time, the blowing and stirring effects of the converter can be obviously improved, the blowing time can be effectively shortened, and the improvement of the production efficiency and the cleanliness of the molten steel can be promoted.

Further, the air outlets 302 of all the bottom-blowing elements 3 are arranged on the same circumference with the center of the furnace bottom 2 as the center. In the present embodiment, the gas outlets 302 of all the bottom-blowing elements 3 are arranged on the same circumference with the center of the furnace bottom 2 as the center of the circle, so that the molten steel in the furnace body forms a set of horizontal circulation and up-and-down circulation under the stirring action of the gas coming in and going out from the bottom-blowing elements 3, which is beneficial to increasing the bottom-blowing efficiency and further improving the blowing and stirring effect.

Wherein, the air outlets 302 of all the bottom blowing elements 3 are uniformly arranged on the same circumference which takes the center of the furnace bottom 2 as the center of a circle; for example, the blow assembly comprises 20 bottom blowing elements 3, and the 20 bottom blowing elements 3 can be evenly distributed on a circumference centered on the center of the furnace bottom 2.

The air outlets 302 of all the bottom-blowing elements 3 can also be arranged non-uniformly on the same circumference with the center of the furnace bottom 2 as the center. For example, the blow assembly comprises 20 bottom blowing elements 3, and the 20 bottom blowing elements 3 may be non-uniformly distributed over a circumference centered on the center of the furnace bottom 2.

Further, the air outlets 302 of all the bottom blowing elements 3 are respectively arranged on 2-5 concentric circles with different radiuses and taking the center of the furnace bottom 2 as the center of the circle. For example, the blowing assembly comprises 20 bottom blowing elements 3, and the 20 bottom blowing elements 3 can be dispersed on 2-5 concentric circles with different radiuses and taking the center of the furnace bottom 2 as the center, so that molten steel forms 2-5 groups of horizontal circulation and up-and-down circulation under the action of gas blown into the furnace body from the 20 bottom blowing elements 3, and the dead volume in the furnace body is further reduced.

Wherein the air outlets 302 of the bottom blowing element 3 located on the circumference of a concentric circle with the same radius are uniformly arranged on the circumference; and/or the air outlets 302 of the bottom-blowing elements 3 lying on the circumference of a concentric circle of the same radius are arranged non-uniformly over this circumference.

In addition, the air outlets 302 on the bottom-blowing elements 3 located on the concentric circumferences of different radii are uniformly arranged on the concentric circumferences of different radii; the air outlets 302 of the bottom-blowing elements 3 located on the concentric circumferences having different radii are not uniformly arranged on the concentric circumferences having different radii.

In a preferred embodiment, the bottom-blowing elements, the furnace wall 1, the furnace bottom 2, the bottom-blowing elements 3 and the brick cup 4 are made of one or both of refractory materials and metal products.

Further, the types of bottom-blowing elements 3 include, but are not limited to, single-layer tubular nozzles, double-layer sleeve nozzles, circular seam tubular nozzles, dispersion air bricks, slit combination bricks, straight hole type air bricks, porous plug type air rotors, circular seam tubular straight hole bricks, and circular seam-like nozzles.

In the steelmaking method provided by the invention, gas is blown into the furnace body from the bottom blowing element 3 on the top-bottom combined blown converter, so that molten steel in the furnace body is stirred.

Specifically, the steelmaking method provided by the invention comprises the following steps:

blowing gas and stirring liquid into the furnace body by a bottom blowing element 3, wherein the gas supply pressure is 0.1-0.8MPa, and the bottom blowing element 3 firstly takes 0.03-1.2Nm³Blowing the steel into the converter for 1-2min at the bottom blowing flow of the steel per min t, and then reducing the bottom blowing flow to 0.02-0.6Nm³Steel,/min t;

after the molten iron in the converter is added, the converter body is shaken up, the oxygen lance is descended, and the blowing time is 75-210Nm³The oxygen supply intensity of the/h t steel was blown off, and the oxygen supply intensity was gradually increased to 150-300Nm before the end of the early stage of blowing³Steel,/h t;

and after blowing for 15-20min, stopping oxygen blowing, turning the furnace, sampling and measuring the temperature to finish steel making.

In a preferred embodiment, the air supply pressure of the air supply unit to which the bottom blowing element 3 is connected is 0.7 to 3.0 MPa.

Wherein, the argon gas is pure argon, the content of the argon is more than or equal to 99.99 percent according to the weight percentage, and the rest is impurity components; the nitrogen is industrial nitrogen, the components by weight percentage are that the nitrogen content is more than or equal to 99.6 percent, the oxygen content is less than or equal to 0.5 percent, and the rest are impurity components.

Example 1

A top-bottom combined blown converter comprises 4 bottom blowing elements 3 arranged on a 120t furnace bottom 2, wherein the air outlets 302 of 2 bottom blowing elements 3 are arranged on 0.6R, the air outlets 302 of the other 2 bottom blowing elements 3 are arranged on 0.67R, the included angle between the centers of the two air outlets 302 on different circumferences and the connecting line of the centers of the furnace bottom 2 is 95 degrees, the included angle between the axial line of a gas channel and the parallel line of the axial line of a furnace wall 1 is 60 degrees, and the included angle is shown in figures 1-3.

Wherein the top blowing oxygen supply pressure is 0.75-1.0MPa, and the bottom blowing gas supply pressure of the bottom blowing element 3 is 0.8-1.2 MPa.

A molten steel steelmaking method comprises the following steps:

(1) after molten iron is added into the furnace body, the furnace body is shaken up, the oxygen lance is descended and the discharge speed is 18000Nm³Blowing was carried out at an oxygen supply rate of 1530Nm for the bottom blowing element³Blowing nitrogen into the converter;

(2) after blowing nitrogen gas for 2min by the bottom-blowing element 3, the bottom-blowing gas was switched to argon gas and the bottom-blowing flow rate was reduced to 1020Nm³Continuing blowing;

(3) before the blowing earlier stage is finished, the oxygen supply intensity is gradually adjusted to 30000Nm³H, and continuing until the blowing is finished;

(4) and after blowing for 15min, stopping oxygen blowing, reversing the furnace, sampling, measuring the temperature, measuring the carbon-oxygen product to be 0.0023, tapping, and obtaining the molten steel with the yield of 96.4 percent.

Example 2

A top-bottom combined blown converter comprises 6 bottom blowing elements 3 arranged on a 120t furnace bottom 2, wherein the air outlets 302 of the 6 bottom blowing elements 3 are uniformly arranged on 0.6R, so that the included angle between the centers of two adjacent air outlets 302 and the connecting line of the centers of the furnace bottom 2 is 60 degrees, and the included angle between the axis of a gas channel and the parallel line of the axis of a furnace wall 1 is 45 degrees, as shown in figure 5.

Wherein the top-blown oxygen supply pressure is 0.75-1.0MPa, and the bottom-blown gas supply intensity of the bottom-blown element 3 is 0.8-1.2 MPa.

A molten steel steelmaking method comprises the following steps:

(1) after molten iron is added into the furnace body, the furnace body is shaken up, the oxygen lance is descended and the discharge speed is 16000Nm³Blowing was carried out at an oxygen supply rate of 1530Nm for the bottom blowing element³Blowing nitrogen into the converter;

(2) after blowing nitrogen gas through the bottom-blowing element 3 for 1min, the bottom-blowing gas was switched to argon gas and the bottom-blowing flow rate was reduced to 1020Nm³Continuing blowing;

(3) before the blowing earlier stage is finished, the oxygen supply intensity is gradually adjusted to 30000Nm³H, and continuing until the blowing is finished;

(4) and after blowing for 15min, stopping oxygen blowing, reversing the furnace, sampling, measuring the temperature, measuring the carbon-oxygen product to be 0.0020, tapping, and obtaining the molten steel with the yield of 96.5 percent.

Example 3

A top-bottom combined blown converter comprises 12 bottom blowing elements 3 arranged on a 300t furnace bottom 2, wherein air outlets 302 of 4 bottom blowing elements 3 are arranged on 0.5R, air outlets 302 of 4 bottom blowing elements 3 are arranged on 0.6R, air outlets 302 of 4 bottom blowing elements 3 are arranged on 0.65R, the included angle between the centers of two adjacent air outlets 302 on different circumferences and the connecting line of the centers of the furnace bottom 2 is 30 degrees, the included angle between the centers of two adjacent air outlets 302 on the same circumference and the connecting line of the centers of the furnace bottom 2 is 90 degrees, and the included angle between the axial line of a gas channel and the parallel line of the axial line of a furnace wall 1 is 30 degrees, as shown in figure 6.

Wherein the top-blown oxygen supply pressure is 0.75-1.0MPa, and the bottom-blown gas supply intensity of the bottom-blown element 3 is 0.8-1.2 MPa.

A molten steel steelmaking method comprises the following steps:

(1) after molten iron is added into the furnace body, the furnace body is shaken up, the oxygen lance is descended and the amount of oxygen is 35000Nm³Blowing was carried out at an oxygen supply rate of 2400Nm for the bottom-blowing element³Blowing nitrogen into the converter;

(2) after blowing nitrogen gas for 2min by the bottom-blowing element 3, the bottom-blowing gas was switched to argon gas and the bottom-blowing flow was reduced to 1600Nm³Continuing blowing;

(3) before the blowing earlier stage is finished, the oxygen supply intensity is gradually increasedGradually adjust to 60000Nm³H, and continuing until the blowing is finished;

(4) and after blowing for 16min, stopping oxygen blowing, reversing the furnace, sampling, measuring the temperature, measuring the carbon-oxygen product to be 0.0018, tapping, and obtaining the molten steel with the yield of 96.1 percent.

Example 4

A top-bottom combined blown converter comprising 6 bottom blowing elements 3 installed in a 300t furnace bottom 2, wherein the outlets 302 of the 2 bottom blowing elements 3 are installed at 0.42R, the outlets 302 of the 2 bottom blowing elements 3 are installed at 0.53R, and the outlets 302 of the 2 bottom blowing elements 3 are installed at 0.67R, so that the centers of the outlets 302 on the circumferences of 0.53R and 0.67R are respectively at an angle of 95 DEG with respect to the line connecting the centers of the furnace bottom 2, and the angle theta between the axis of the gas passage and the line parallel to the axis of the furnace wall 1 is 45 DEG, as shown in FIG. 7.

Wherein the top-blown oxygen supply pressure is 0.75-1.0MPa, and the bottom-blown gas supply intensity of the bottom-blown element 3 is 0.8-1.2 MPa.

A molten steel steelmaking method comprises the following steps:

(1) after molten iron is added into the furnace body, the furnace body is shaken up, the oxygen lance is descended and 40000Nm is used³Blowing was carried out at an oxygen supply rate of 2400Nm for the bottom-blowing element³Blowing nitrogen into the converter;

(2) after blowing nitrogen gas for 2min by the bottom-blowing element 3, the bottom-blowing gas was switched to argon gas and the bottom-blowing flow was reduced to 1600Nm³Continuing blowing;

(3) before the blowing earlier stage is finished, the oxygen supply intensity is gradually adjusted to 60000Nm³H, and continuing until the blowing is finished;

(4) and after blowing for 16min, stopping oxygen blowing, reversing the furnace, sampling, measuring the temperature, measuring the carbon-oxygen product to be 0.0020, tapping, and obtaining the molten steel with the yield of 95.8 percent.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.