Synchronous stirring and blowing desulfurization gun and stirring and blowing desulfurization method thereof

Abstract

The invention provides a synchronous stirring and blowing desulfurization gun and a stirring and blowing desulfurization method thereof.The desulfurization gun comprises an upper stirring paddle, a middle reinforcing paddle, a central rotating shaft, a hollow powder gas channel and a lower stirring paddle, the upper stirring paddle is arranged on the upper portion of the central rotating shaft, and the middle reinforcing paddle is arranged in the middle of the central rotating shaft; the lower stirring paddle is arranged at the lower part of the central rotating shaft; a hollow powder gas channel is formed in the center of the central rotating shaft; the desulfurization gun rotates by taking the central rotating shaft as an axis, and the hollow powder gas channel conveys desulfurization powder to a nozzle of the lower stirring paddle through a gas carrier to be sprayed out; the desulfurization gun stirs molten iron and breaks bubbles, so that desulfurization powder in the bubbles is fully fused with the molten iron, and the desulfurization reaction is promoted. Through the stirring paddle structure, the stirring paddle rotating speed, the injection depth, the injection mode and the injection included angle, the dynamic conditions of molten iron in the desulfurization process are optimized, and the desulfurization efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of molten iron pretreatment in steel metallurgy, and in particular to a synchronous stirring and spraying desulfurization gun and a stirring and spraying desulfurization method thereof. Background Art

[0002] With the continuous development of science and technology, the public's requirements for the quality of steel are constantly increasing. Sulfur is the main factor causing the "hot brittleness" problem of steel. In the steelmaking process, desulfurization is a key step to improve the quality of molten steel and improve the performance of steel.

[0003] There are two important methods of traditional desulfurization, including mechanical stirring and injection. The mechanical stirring method mainly involves inserting a stirring head lined with refractory materials into the molten iron tank. Through the rotation of the stirring head and the high-speed movement of the stirring blades, the desulfurizer and the molten iron are fully mixed, thereby improving the desulfurization efficiency. This treatment method has a good desulfurization effect and a short treatment time, but it has a large temperature drop on the molten iron. The injection method uses gas as a carrier to spray the desulfurizer into the molten iron tank through a spray gun. The injection method has low equipment investment costs and a small temperature drop on the molten iron, but the kinetic conditions are poor and the utilization rate of the desulfurizer is low.

[0004] Therefore, it is necessary to combine the mechanical stirring method with the desulfurization method and invent a desulfurization gun for stirring and blowing to make up for the shortcomings of the stirring method and the blowing method and improve the desulfurization effect. Summary of the invention

[0005] According to the technical problems raised above, a synchronous stirring and spraying desulfurization gun and a stirring and spraying desulfurization method thereof are provided. The present invention mainly applies a new stirring paddle that combines rotary stirring and composite spraying to a stirring and spraying desulfurization gun, and optimizes the molten iron dynamic conditions in the desulfurization process and improves the desulfurization efficiency through the stirring paddle structure, stirring paddle rotation speed, spraying depth, spraying mode and spraying angle.

[0006] The technical means adopted by the present invention are as follows:

[0007] A synchronous stirring and blowing desulfurization gun is used in a molten iron tank for steel smelting, comprising: an upper stirring paddle, a middle strengthening paddle, a central rotating shaft, a hollow powder gas channel and a lower stirring paddle, wherein:

[0008] The upper stirring paddle is arranged at the upper part of the central rotating shaft, the middle reinforcing paddle is arranged at the middle part of the central rotating shaft, the lower stirring paddle is arranged at the lower part of the central rotating shaft, and a hollow powder gas channel is arranged at the center of the central rotating shaft;

[0009] The desulfurization gun rotates around the central rotation axis, and the hollow powder-gas channel transmits the desulfurization powder to the nozzle of the lower stirring paddle through the gas carrier for spraying out; the desulfurization gun stirs the molten iron and breaks up the bubbles at the same time, so that the desulfurization powder in the bubbles is fully integrated with the molten iron, thereby promoting the desulfurization reaction.

[0010] Furthermore, the upper stirring paddle, the middle reinforcing paddle and the lower stirring paddle are all composed of multiple blades;

[0011] The upper surface of the upper stirring paddle is flush with or lower than the upper surface of the molten iron; the lower stirring paddle is provided with a nozzle, the nozzle is arranged at the end of the blade of the lower stirring paddle or between the blades, the nozzle is arranged obliquely downward, and the angle with the horizontal direction is 0 to 40 degrees; the lower stirring paddle is at a certain distance from the bottom of the molten iron tank.

[0012] Furthermore, the upper stirring paddle, the middle reinforcing paddle and the lower stirring paddle are made of high-temperature-resistant and corrosion-resistant high-aluminum refractory materials, corundum refractory materials, mullite refractory materials or silicon carbide refractory materials.

[0013] Furthermore, the central rotating shaft is made of heat-resistant steel, and the surface is provided with aluminum-silicon refractory material with a refractoriness of 1500-1800°C.

[0014] Furthermore, the desulfurization powder is a mixture of limestone, magnesium powder, calcium carbide, fluorite and various powders.

[0015] Furthermore, the gas carrier is selected from an inert gas or a reducing gas.

[0016] The present invention also includes a stirring and spraying desulfurization method, comprising:

[0017] Measure the latitude of the molten iron ladle, and calculate the height, upper side length and lower side length of the upper stirring paddle, the middle reinforcing paddle and the lower stirring paddle according to the dimensional information of the molten iron ladle;

[0018] Take temperature measurements and samples of the molten iron in the molten iron tank to detect the initial sulfur content in the molten iron;

[0019] According to the measured initial sulfur content and the type of steel, the dosage of desulfurization powder is calculated through the desulfurization model;

[0020] The desulfurization powder is continuously sprayed out from the nozzle of the lower stirring paddle, and at the same time, the upper stirring paddle, the middle strengthening paddle and the lower stirring paddle start to rotate;

[0021] After the desulfurization powder and molten iron have fully reacted, the desulfurization slag floating on the surface of the molten iron is scraped off by a slag scraper to complete the desulfurization operation.

[0022] Further, the height, upper side length and lower side length of the upper stirring paddle, the middle reinforcing paddle and the lower stirring paddle blades are calculated respectively according to the dimensional information of the molten iron ladle, including:

[0023] The height, upper side length and lower side length of the upper stirring paddle are represented as H1, a1 and b1 respectively:

[0024] H1=α×h

[0025] a1=β×r

[0026] b1=γ×β×r

[0027] Among them, h is the height of the molten iron tank, r is the radius of the molten iron tank, α is the empirical coefficient of the height of the upper stirring paddle blade, β is the empirical coefficient of the upper side length of the upper stirring paddle blade, and γ is the empirical coefficient of the lower side length of the upper stirring paddle blade;

[0028] The height, upper side length and lower side length of the middle reinforced paddle are expressed as H2, a2 ​​and b2 respectively:

[0029] a2=μ×r

[0030] b2=σ×μ×r

[0031] H2=τ×h

[0032] Among them, μ is the empirical coefficient of the upper side length of the middle reinforced propeller blade, σ is the empirical coefficient of the lower side length of the middle reinforced propeller blade, and τ is the empirical coefficient of the height of the middle reinforced propeller blade;

[0033] The height, upper side length and lower side length of the middle reinforced propeller are expressed as H3, a3 and b3 respectively:

[0034] H3=m×h

[0035] a3=n×r

[0036] b3=o×n×r

[0037] Among them, m is the empirical coefficient of the height of the lower stirring paddle blade; n is the empirical coefficient of the upper side length of the lower stirring paddle blade, and o is the empirical coefficient of the lower side length of the lower stirring paddle blade.

[0038] Compared with the prior art, the present invention has the following advantages:

[0039] The present invention provides a synchronous stirring and blowing desulfurization gun and a stirring and blowing desulfurization method thereof, which combine rotary stirring with composite blowing, and efficiently rotate the stirring paddle in the molten iron tank, thereby improving the dynamic conditions in the molten iron tank, promoting the uniform dispersion of desulfurizer particles inside the molten pool, and increasing the contact area between the desulfurizer and the molten iron; the desulfurization powder is sprayed into the deep part of the molten iron\semi-steel molten pool from the lower stirring paddle at an inclined angle by means of rotary blowing, thereby enhancing the dispersion effect of the desulfurizer particles inside the molten pool, enabling the desulfurization powder to obtain sufficient kinetic energy to prolong the residence time in the molten pool, thereby realizing deep desulfurization.

[0040] Based on the above reasons, the present invention can be widely promoted in the fields of molten iron pretreatment in steel metallurgy. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0042] Figure 1 It is a schematic diagram of the structure of the desulfurization gun with synchronous stirring and blowing in the present invention.

[0043] Figure 2 Schematic diagram of the upper stirring paddle structure in an embodiment of the present invention.

[0044] Figure 3 Schematic diagram of the lower stirring paddle structure with built-in nozzle in an embodiment of the present invention.

[0045] Figure 4 Schematic diagram of the structure of the lower stirring paddle with nozzles arranged between the blades in an embodiment of the present invention.

[0046] In the figure: 1. upper stirring paddle; 2. molten iron ladle; 3. middle reinforcing paddle; 4. central rotating shaft; 5. hollow powder gas channel; 6. lower stirring paddle; a1. four-blade upper stirring paddle; b1. five-blade upper stirring paddle; c1. six-blade upper stirring paddle; a2. two-blade lower stirring paddle sprayed at the end; b2. three-blade lower stirring paddle sprayed at the end c2. four-blade lower stirring paddle sprayed at the end; d2. five-blade lower stirring paddle sprayed at the end; e2. six-blade lower stirring paddle sprayed at the end; a3. two-blade lower stirring paddle sprayed between the blades; b3. three-blade lower stirring paddle sprayed between the blades; c3. four-blade lower stirring paddle sprayed between the blades; d3. five-blade lower stirring paddle sprayed between the blades; e3. six-blade lower stirring paddle sprayed between the blades. DETAILED DESCRIPTION

[0047] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0048] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0049] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0050] Unless otherwise specifically stated, the relative arrangement of the parts and steps described in these embodiments, the numerical expressions and numerical values ​​do not limit the scope of the present invention. At the same time, it should be clear that, for ease of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship. The technology, methods and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be regarded as part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar numbers and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0051] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention: the directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0052] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below their position devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0053] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0054] like Figure 1 As shown, the present invention provides a synchronous stirring and blowing desulfurization gun, which is used in a molten iron tank for steel smelting, comprising: an upper stirring paddle 1, a middle strengthening paddle 3, a central rotating shaft 4, a hollow powder gas channel 5 and a lower stirring paddle 6, wherein:

[0055] The upper stirring paddle 1 is arranged at the upper part of the central rotating shaft 4, the middle reinforcing paddle 3 is arranged at the middle part of the central rotating shaft 4, the lower stirring paddle 6 is arranged at the lower part of the central rotating shaft 4, and a hollow powder gas channel 5 is arranged at the center of the central rotating shaft 4;

[0056] The desulfurization gun rotates around the central rotating shaft 4, and the hollow powder-gas channel 5 transmits the desulfurization powder to the nozzle of the lower stirring paddle 6 through the gas carrier for spraying; the desulfurization gun stirs the molten iron and breaks the bubbles at the same time, so that the desulfurization powder in the bubbles fully merges with the molten iron to promote the desulfurization reaction. The sprayed powder-gas bubbles are broken by stirring, and the powder and bubbles are discretely distributed in the molten iron; the powder-gas bubbles float in the molten iron, and the solid powder therein gradually gathers above the molten iron to form slag. The desulfurizer and slag in the molten iron both react with the sulfur in the molten iron, and the desulfurization gun promotes the desulfurization reaction of the two while rotating and stirring.

[0057] During implementation, the hollow powder-gas channel 5 of the central rotating shaft 4 transmits the desulfurization powder to the powder-gas nozzle at the lower end of the desulfurization gun through the gas carrier. The desulfurization powder can be directly sprayed from the nozzle at the lower end of the central rotating shaft 4, or sprayed from the nozzle at the end of the blade of the lower stirring paddle 6 or the nozzle between adjacent blades. The diameter of the powder-gas nozzle at the center of the central rotating shaft is 30-35 mm. If the powder is directly sprayed from the lower end of the central rotating shaft 4, the diameter of the powder-gas nozzle is the same as the diameter of the powder-gas channel in the central shaft. If the powder is sprayed from the end of the stirring paddle blade and between the blades, the diameter of the powder-gas nozzle is in the range of 15-18 mm.

[0058] In specific implementation, as a preferred embodiment of the present invention, the upper stirring paddle 1, the middle reinforcing paddle 3 and the lower stirring paddle 6 are all composed of multiple blades;

[0059] The upper surface of the upper stirring paddle 1 is flush with or lower than the upper surface of the molten iron; the lower stirring paddle 6 is provided with a nozzle, and the nozzle is arranged at the end of the blade of the lower stirring paddle 6 or between the blades. The nozzle is arranged obliquely downward, and the angle with the horizontal direction is 0 to 40 degrees; the lower stirring paddle 6 is at a certain distance from the bottom of the molten iron tank.

[0060] During implementation, the lower stirring paddle installed at the lower end of the desulfurization gun is 200-1600mm away from the bottom of the molten iron tank and has a thickness range of 100-250mm. Its main function is to stir the molten iron in the lower part of the molten iron tank, break up the blown powder gas bubbles, and push the bubbles away from the central axis of the molten iron tank, so that the blown-in bubbles are more discrete in the molten iron.

[0061] The upper stirring paddle is flush with the upper surface of the slag, or located within 20 cm above and below the upper surface of the slag; the paddle thickness is 150-200mm, and its main function is to stir the slag and molten iron on the upper part of the molten iron tank, and push the slag on the upper part of the molten iron into the molten iron below to promote the slag-iron reaction; the material can be aluminum-magnesium refractory material.

[0062] The middle reinforcing paddle is located between the upper and lower stirring paddles. Its function is to strengthen the stirring of the molten iron in the middle of the molten iron tank and the discretization of the powder gas bubbles. It can also help to strengthen the stirring effect of the upper stirring paddle. The thickness of the paddle is 100-250mm. If there is less molten iron in the molten iron tank and the distance between the upper and lower stirring paddles is less than 1500mm, the middle reinforcing paddle can be omitted.

[0063] The stirring speed of the lower stirring paddle, the upper stirring paddle and the middle strengthening paddle ranges from 30 to 200 r / min.

[0064] In specific implementation, as a preferred embodiment of the present invention, the upper stirring paddle 1, the middle reinforcing paddle 3 and the lower stirring paddle 6 are made of high-temperature resistant and corrosion-resistant high-aluminum refractory materials, corundum refractory materials, mullite refractory materials or silicon carbide refractory materials. The refractoriness of high-aluminum refractory materials is usually above 1770°C, the refractoriness of corundum refractory materials and aluminum-magnesium refractory materials is usually above 1800°C, the refractoriness of mullite refractory materials is usually above 1750°C, and the refractoriness of silicon carbide refractory materials is usually in the range of 1600-1700°C.

[0065] In specific implementation, as a preferred embodiment of the present invention, the central rotating shaft 4 is made of heat-resistant steel, and the surface is provided with aluminum-silicon refractory material with a refractoriness of 1500-1800°C, so as to ensure that it can maintain a stable working state when rotating at high speed and bearing a large load.

[0066] In specific implementation, as a preferred embodiment of the present invention, the desulfurization powder is a mixture of limestone, magnesium powder, calcium carbide, fluorite and various powders.

[0067] In specific implementation, as a preferred embodiment of the present invention, the gas carrier is selected from inert gases such as nitrogen and argon or gases with reducing properties such as methane and hydrogen.

[0068] The present invention also includes a desulfurization method for stirring and spraying corresponding to a desulfurization gun for synchronous stirring and spraying, comprising:

[0069] Measure the latitude of the molten iron ladle, and calculate the height, upper side length and lower side length of the upper stirring paddle 1, the middle reinforcing paddle 3 and the lower stirring paddle 6 according to the dimensional information of the molten iron ladle;

[0070] Take temperature measurements and samples of the molten iron in the molten iron tank to detect the initial sulfur content in the molten iron;

[0071] According to the measured initial sulfur content and the type of steel, the dosage of desulfurization powder is calculated through the desulfurization model;

[0072] The desulfurization powder is continuously sprayed out from the nozzle of the lower stirring paddle 4, and at the same time, the upper stirring paddle 1, the middle reinforcing paddle 3 and the lower stirring paddle 6 start to rotate;

[0073] After the desulfurization powder and molten iron have fully reacted, the desulfurization slag floating on the surface of the molten iron is scraped off by a slag scraper to complete the desulfurization operation.

[0074] In specific implementation, as a preferred embodiment of the present invention, the height, upper side length and lower side length of the upper stirring paddle 1, the middle reinforcing paddle 3 and the lower stirring paddle 6 are calculated according to the dimensional information of the molten iron ladle, including:

[0075] The height, upper side length and lower side length of the upper stirring paddle 1 are represented as H1, a1 and b1 respectively:

[0076] H1=α×h

[0077] a1=β×r

[0078] b1=γ×β×r

[0079] Among them, h is the height of the molten iron tank, r is the radius of the molten iron tank, α is the empirical coefficient of the height of the upper stirring paddle 1 blade, α is 0.065~0.08, γ is the empirical coefficient of the lower side length of the upper stirring paddle 1 blade, γ is 0.4~1; β is the empirical coefficient of the upper side length of the upper stirring paddle 1 blade, β is 0.046~0.093.

[0080] The height, upper side length and lower side length of the middle reinforcing paddle 3 are represented as H2, a2 ​​and b2 respectively:

[0081] a2=μ×r

[0082] b2=σ×μ×r

[0083] H2=τ×h

[0084] Among them, μ is the empirical coefficient of the upper side length of the middle reinforced propeller 3 blades, μ is 0.046-0.139, σ is the empirical coefficient of the lower side length of the middle reinforced propeller 3 blades, σ is 0.27-1, τ is the empirical coefficient of the height of the middle reinforced propeller 3 blades; τ is 0.052~0.088.

[0085] The height, upper side length and lower side length of the middle reinforcing paddle 3 are represented as H3, a3 and b3 respectively:

[0086] H3=m×h

[0087] a3=n×r

[0088] b3=o×n×r

[0089] Among them, m is the empirical coefficient of the height of the blade of the lower stirring paddle 6, and m is 0.052~0.088; n is the empirical coefficient of the upper side length of the blade of the lower stirring paddle 6, and n is 0.07~0.139; o is the empirical coefficient of the lower side length of the blade of the lower stirring paddle 6, and o is 0.33~1.

[0090] Example 1

[0091] like Figure 1 As shown, the present invention provides a synchronous stirring and spraying desulfurization gun and a stirring and spraying desulfurization method thereof. The desulfurization gun in this embodiment is a rotatable stirring gun with multiple groups of stirring blades installed at different positions of its central rotating shaft; the central rotating shaft is a hollow powder gas channel, which is made of heat-resistant steel and covered with aluminum silicon refractory material to ensure that it can maintain a stable working state when rotating at high speed and bearing a large load. The hollow powder gas channel transmits the desulfurization powder to the powder gas nozzle at the lower end of the desulfurization gun, and the desulfurizer is sprayed into the molten iron from the end of the lower stirring blade at 30°. The detailed desulfurization process includes:

[0092] Take temperature measurements and samples from a molten iron tank containing 100 tons of molten iron to detect the initial sulfur content in the molten iron;

[0093] According to the measured sulfur content and the type of steel, the desulfurization agent dosage is calculated through the desulfurization model;

[0094] Lower the stirring paddle under the desulfurization gun to 400mm from the bottom of the molten iron tank, and continuously spray the desulfurizer from the end of the four-blade lower stirring paddle. The spraying speed of magnesium powder is 8kg / min, and the spraying speed of limestone is 30kg / min. While spraying, the lower stirring paddle and the upper stirring paddle rotate at a speed of 30r / min to disperse the magnesium bubbles into fine bubbles, so that the magnesium bubbles stay in the molten iron longer.

[0095] After the desulfurizer and molten iron have fully reacted, the desulfurization is completed, and the desulfurization slag floating on the surface of the molten iron is removed by a slag scraper;

[0096] After the molten iron pretreatment and slag removal operation is completed, the molten iron ladle is lifted by a crane and the treated molten iron is added to the converter.

[0097] Example 2

[0098] In this embodiment, a four-blade intermediate reinforcing paddle is provided between the upper stirring paddle and the lower stirring paddle, and its function is to strengthen the stirring of the molten iron in the middle of the molten iron tank and the discretization of the powder gas bubbles, and it can also help strengthen the stirring effect of the upper stirring paddle, and its material is the same as that of the lower stirring paddle. The desulfurization gun is a rotatable stirring spray gun with multiple sets of stirring blades installed at different positions on its central rotating axis; the central rotating axis is a hollow powder gas channel, which is made of heat-resistant steel and covered with aluminum-silicon refractory materials to ensure that it can maintain a stable working state when rotating at high speed and bearing large loads. The hollow powder gas channel transmits the desulfurization powder to the powder gas nozzle at the lower end of the desulfurization gun, and the desulfurizer is sprayed into the molten iron from between the blades of the lower stirring paddle at 25°. The detailed desulfurization process includes the following steps:

[0099] Take temperature measurements and samples from a molten iron tank containing 350 tons of molten iron to detect the initial sulfur content in the molten iron;

[0100] According to the measured sulfur content and the type of steel, the desulfurization agent dosage is calculated through the desulfurization model;

[0101] Lower the stirring paddle under the desulfurization gun to 1400mm from the bottom of the molten iron tank, and continuously spray the desulfurizer from the end of the four-blade lower stirring paddle. The spraying speed of magnesium powder is 15kg / min, and the spraying speed of limestone is 45kg / min. While spraying, the lower stirring paddle and the upper stirring paddle rotate at a speed of 120r / min to disperse the magnesium bubbles into fine bubbles, so that the magnesium bubbles stay in the molten iron longer.

[0102] After the desulfurizer and molten iron have fully reacted, the desulfurization is completed, and the desulfurization slag floating on the surface of the molten iron is removed by a slag scraper;

[0103] After the molten iron pretreatment and slag removal operation is completed, the molten iron ladle is lifted by a crane and the treated molten iron is added to the converter.

[0104] The present invention uses a new type of stirring paddle to perform rotary stirring and composite blowing in the molten iron tank, thereby improving the dynamic conditions in the molten iron tank, promoting the uniform dispersion of desulfurizer particles in the molten pool, and increasing the contact area between the desulfurizer and the molten iron; the device of the present invention significantly improves the desulfurization efficiency and magnesium utilization rate and reduces production costs by proposing a new type of stirring paddle and a molten iron pretreatment desulfurization process.

[0105] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A synchronous stirring and spraying desulfurization gun, used in a molten iron tank for steel smelting, characterized in that: include: An upper stirring paddle (1), a middle reinforcing paddle (3), a central rotating shaft (4), a hollow powder gas channel (5) and a lower stirring paddle (6), wherein: The upper stirring paddle (1) is arranged at the upper part of the central rotating shaft (4), the middle reinforcing paddle (3) is arranged at the middle part of the central rotating shaft (4), the lower stirring paddle (6) is arranged at the lower part of the central rotating shaft (4), and a hollow powder gas channel (5) is arranged at the center of the central rotating shaft (4); The desulfurization gun rotates around the central rotation axis (4), and the hollow powder-gas channel (5) transmits the desulfurization powder to the nozzle of the lower stirring paddle (6) through the gas carrier for spraying out; the desulfurization gun stirs the molten iron and breaks up the bubbles at the same time, so that the desulfurization powder in the bubbles is fully integrated with the molten iron, thereby promoting the desulfurization reaction.

2. A synchronous stirring and spraying desulfurization gun according to claim 1, characterized in that: The upper stirring paddle (1), the middle reinforcing paddle (3) and the lower stirring paddle (6) are all composed of a plurality of paddle blades; The upper surface of the upper stirring paddle (1) is flush with or lower than the upper surface of the molten iron; the lower stirring paddle (6) is provided with a nozzle, the nozzle is arranged at the end of the blade of the lower stirring paddle (6) or between the blades, the nozzle is arranged obliquely downward, and the angle with the horizontal direction is 0 to 40 degrees; the lower stirring paddle (6) is at a certain distance from the bottom of the molten iron tank.

3. A synchronous stirring and spraying desulfurization gun according to claim 1, characterized in that: The upper stirring paddle (1), the middle reinforcing paddle (3) and the lower stirring paddle (6) are made of high-temperature-resistant and corrosion-resistant high-aluminum refractory materials, corundum refractory materials, mullite refractory materials or silicon carbide refractory materials.

4. A synchronous stirring and blowing desulfurization gun according to claim 1, characterized in that: The central rotating shaft (4) is made of heat-resistant steel, and its surface is provided with aluminum-silicon refractory material with a refractoriness of 1500-1800°C.

5. The desulfurization gun with synchronous stirring and spraying according to claim 1 is characterized in that: The desulfurization powder is a mixture of limestone, magnesium powder, calcium carbide, fluorite and various powders.

6. The desulfurization gun with synchronous stirring and spraying according to claim 1 is characterized in that: The gas carrier is selected from an inert gas or a reducing gas.

7. A desulfurization method using stirring and spraying based on the desulfurization gun with synchronous stirring and spraying as described in any one of claims 1 to 6, characterized in that: include: Measure the latitude of the molten iron ladle, and calculate the height, upper side length and lower side length of the upper stirring paddle (1), the middle reinforcing paddle (3) and the lower stirring paddle (6) according to the dimensional information of the molten iron ladle; Take temperature measurements and samples of the molten iron in the molten iron tank to detect the initial sulfur content in the molten iron; According to the measured initial sulfur content and the type of steel, the dosage of desulfurization powder is calculated through the desulfurization model; The desulfurization powder is continuously sprayed out from the nozzle of the lower stirring paddle (4), and at the same time, the upper stirring paddle (1), the middle reinforcing paddle (3) and the lower stirring paddle (6) start to rotate; After the desulfurization powder and molten iron have fully reacted, the desulfurization slag floating on the surface of the molten iron is scraped off by a slag scraper to complete the desulfurization operation.

8. The desulfurization method of stirring injection according to claim 7, characterized in that: The method of calculating the height, upper side length and lower side length of the blades of the upper stirring paddle (1), the middle reinforcing paddle (3) and the lower stirring paddle (6) respectively according to the dimensional information of the molten iron ladle comprises: The height, upper side length and lower side length of the upper stirring paddle (1) are represented as H1, a1 and b1 respectively: H1=α×h a1＝β×r b1=γ×β×r Wherein, h is the height of the molten iron tank, r is the radius of the molten iron tank, α is the empirical coefficient of the height of the upper stirring paddle (1), β is the empirical coefficient of the upper side length of the upper stirring paddle (1), and γ is the empirical coefficient of the lower side length of the upper stirring paddle (1); The height, upper side length and lower side length of the middle reinforcing paddle (3) are represented as H2, a2 ​​and b2 respectively: a2=μ×r b2=σ×μ×r H2=τ×h Wherein, μ is the empirical coefficient of the upper side length of the blade of the middle reinforced propeller (3), σ is the empirical coefficient of the lower side length of the blade of the middle reinforced propeller (3), and τ is the empirical coefficient of the height of the blade of the middle reinforced propeller (3); The height, upper side length and lower side length of the middle reinforcing paddle (3) are represented as H3, a3 and b3 respectively: H3=m×h a3=n×r b3=o×n×r Wherein, m is the empirical coefficient of the height of the blade of the lower stirring paddle (6); n is the empirical coefficient of the upper side length of the blade of the lower stirring paddle (6); and o is the empirical coefficient of the lower side length of the blade of the lower stirring paddle (6).

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