Desulfurization method for prolonging service life of desulfurization rotary stirring spray gun

Abstract

The invention discloses a desulfurization method capable of prolonging the service life of a desulfurization rotary stirring spray gun, which comprises the following steps: carrying out rotary injection stirring desulfurization on semisteel subjected to vanadium extraction treatment, and ensuring that the desulfurization time is T; at the stage that the desulfurization time is 0-1 / 4 T, a desulfurization rotary stirring spray gun is inserted below the liquid level of a semi-steel ladle, the depth of a molten pool is 20%-30%, and the rotation speed is 30-50 r / min; at the stage that the desulfurization time is 1 / 4-1 / 2 T, a desulfurization rotary stirring spray gun is inserted below the liquid level of a semisteel ladle, the depth of a molten pool is 30-60%, and the rotation speed is 60-90 r / min; and in the stage that the desulfurization time is 1 / 2T-3 / 4T, a desulfurization rotary stirring spray gun is inserted below the liquid level of a semi-steel ladle, the depth of a molten pool is 60-80%, and the rotation speed is 90-120r / min. According to the desulfurization method, the service life of the rotary blowing stirring spray gun is prolonged from about 1000 min to 1500 min or above.

Description

Technical Field

[0001] The present application relates to the field of steel smelting, and in particular to a desulfurization method for increasing the service life of a desulfurization rotary stirring lance. Background Art

[0002] The sulfur content of steel directly affects its performance. Excessive sulfur content can impair hot working properties, causing the steel to become "hot brittle." It can also significantly reduce weldability and cause high-temperature cracking. Steel's plasticity also deteriorates significantly with increasing sulfur content. High sulfur content in pure iron or silicon steel sheets increases hysteresis losses. Therefore, desulfurization is a primary goal in steelmaking. Pre-desulfurization prior to converter steelmaking is an essential technical measure for producing low-sulfur, clean steel.

[0003] However, sulfur control during smelting is challenging for companies using vanadium-titanium iron ore as raw material. The hot metal produced by blast furnaces using vanadium-titanium magnetite differs from conventional hot metal in several ways: lower furnace temperatures and poor blast furnace desulfurization capacity. The resulting hot metal content is, on average, 0.030-0.040 percentage points higher and 40-50°C lower than that of other domestic steel mills that do not use vanadium-titanium magnetite. Consequently, hot metal desulfurization results in a significant drop in temperature, poor slag quality, and high iron losses. This is particularly true for vanadium-containing hot metal. Due to the unique characteristics of vanadium-containing hot metal, desulfurizer consumption and iron losses increase significantly after desulfurization, leading to a decrease in desulfurization capacity. Furthermore, after desulfurization, the hot metal undergoes vanadium extraction in a converter. The addition of coolant and / or pig iron during this extraction process can lead to significant resulfurization of the semi-steel, hindering sulfur control during steelmaking. Therefore, optimization of the pretreatment desulfurization process for vanadium-titanium hot metal is necessary. Over the long-term process of technological development, a new desulfurization technology, rotary jet agitation desulfurization, has gradually emerged, combining the advantages of KR mechanical agitation desulfurization and injection desulfurization. This technology has achieved improved desulfurization kinetics, significantly improved the reaction conditions between the desulfurizer and molten iron / semi-steel, and significantly increased desulfurizer utilization. However, this technology also has certain technical challenges. Since injection requires the lance to be inserted close to the bottom of the tank, the lance body is relatively long. The addition of agitation blades to the end of the lance increases the lance body's weight. The addition of the rotation function significantly reduces the lance body's stability during the desulfurization process, resulting in a shorter lance life and affecting production rhythm and cost control.

[0004] Therefore, it is an urgent problem for those skilled in the art to develop a method that can control the semi-steel desulfurization cycle in sections to ensure different insertion depths and at the same time increase the life of the desulfurization rotary stirring spray gun. Summary of the Invention

[0005] In view of this, the present application provides a desulfurization method for increasing the service life of a desulfurization rotary stirring spray gun, which has the advantages of simple process flow and good use effect, improves the desulfurization conditions, and increases the service life of the desulfurization gun.

[0006] The present application provides a desulfurization method for increasing the service life of a desulfurization rotary stirring lance, comprising:

[0007] The semi-steel after vanadium extraction is subjected to rotary spray stirring desulfurization, and the desulfurization time is T;

[0008] During the desulfurization time of 0 to 1 / 4T, the desulfurization rotary stirring lance is inserted below the liquid level of the semi-steel ladle and 20% to 30% of the molten pool depth, which can be 20%, 22%, 24%, 26%, 28%, or 30%. The rotation speed is 30 to 50r / min, which can be 30r / min, 32r / min, 34r / min, 36r / min, 38r / min, 40r / min, 42r / min, 44r / min, 46r / min, 48r / min, or 50r / min.

[0009] The desulfurization time is in the stage of 1 / 4T to 1 / 2T. The desulfurization rotary stirring lance is inserted below the liquid level of the semi-steel ladle and 30% to 60% of the molten pool depth, which can be 30%, 32%, 34%, 36%, 38%, 40%, 42%, 44%, 46%, 48%, 50%, 52%, 54%, 56%, 58%, 60%. The rotation speed is 60 to 90r / min, which can be 60r / min, 62r / min, 64r / min, 66r / min, 68r / min, 70r / min, 72r / min, 74r / min, 76r / min, 78r / min, 80r / min, 82r / min, 84r / min, 86r / min, 88r / min, 90r / min;

[0010] The desulfurization time is in the stage of 1 / 2T to 3 / 4T. The desulfurization rotary stirring lance is inserted below the liquid level of the semi-steel ladle and 60% to 80% of the molten pool depth, which can be 60%, 62%, 64%, 66%, 68%, 70%, 72%, 74%, 76%, 78%, 80%. The rotation speed is 90 to 120r / min, which can be 90r / min, 92r / min, 94r / min, 96r / min, 98r / min, 100r / min, 102r / min, 104r / min, 106r / min, 108r / min, 110r / min, 112r / min, 114r / min, 116r / min, 118r / min, 120r / min;

[0011] During the desulfurization time from 3 / 4T to the end, the desulfurization rotary stirring lance is inserted below the liquid level of the semi-steel ladle and 50% to 70% of the molten pool depth. The speed can be 50%, 52%, 54%, 56%, 58%, 60%, 62%, 64%, 66%, 68%, 70%, and the rotation speed is 80 to 100r / min, 80r / min, 82r / min, 84r / min, 86r / min, 88r / min, 90r / min, 92r / min, 94r / min, 96r / min, 98r / min, 100r / min.

[0012] By controlling the semi-steel desulfurization cycle in sections, using different rotary lance insertion depths and rotation speeds at different stages, the slag-steel mixture that adheres to the lance due to the slag-metal interface at different stages is pressed into the semi-steel, where it is melted and separated by the interaction between the semi-steel and the lance. The gradual descent of the lance allows for continuous preheating of the lance, reducing the detachment and loss of refractory material from the lance due to thermal stress, thereby extending the life of the lance. Simultaneously, the lance's insertion depth is gradually increased to ensure that the desulfurizer can fully interact with the semi-steel within the tank, reducing vibration and stress corrosion caused by the lance's long length and high rotation speed, thereby extending the life of the rotary blasting and stirring desulfurization lance. Slowing the rotation speed in the final stage reduces the probability of iron sticking to the lance, effectively reducing iron loss during desulfurization and ensuring slag-metal separation.

[0013] This method requires no specific number of blades in the rotating agitator. It also has the advantage of forcing the slag-steel mixture, which has adhered to the spray gun due to the slag-metal interface at different stages, into the semi-steel, melting and separating it through the interaction between the semi-steel and the spray gun. Furthermore, the gradual descent of the spray gun allows for continuous preheating of the gun, reducing the risk of refractory material peeling and falling due to thermal stress, thereby extending the life of the gun. In some specific implementations, the desulfurizer injection port can be located on the blade or at the end of the agitator shaft.

[0014] In some specific implementations, the desulfurization time T is determined according to the following formula:

[0015] T=(S 初 -S 终 ) / S s ;

[0016] Among them, S 初 is the sulfur content of semi-steel before desulfurization, / %; S 终 is the sulfur content required to be reached at the end of desulfurization, / %; S s The sulfur removal rate of semi-steel / %.min -1 .

[0017] The sulfur content of the semi-steel before desulfurization is 0.12%≤S 初When the content is ≤1%, the sulfur removal rate of semi-steel is 0.0035% / min to 0.0040% / min, which can be 0.0035% / min, 0.0036% / min, 0.0037% / min, 0.0038% / min, 0.0039% / min, 0.0040% / min;

[0018] The sulfur content of the semi-steel before desulfurization is 0.1%≤S 初 When the sulfur content is less than 0.12%, the semi-steel sulfur removal rate is 0.0030% / min to 0.0035% / min, which can be 0.0030% / min, 0.00031% / min, 0.0032% / min, 0.0033% / min, 0.0034% / min, 0.0035% / min;

[0019] The sulfur content of the semi-steel before desulfurization is 0.0001%≤S 初 When the sulfur content is less than 0.1%, the sulfur removal rate of semi-steel is 0.0025% / min to 0.0035% / min, and can be 0.0025% / min, 0.0026% / min, 0.0027% / min, 0.0028% / min, 0.0029% / min, 0.0030% / min, 0.00031% / min, 0.0032% / min, 0.0033% / min, 0.0034% / min, and 0.0035% / min.

[0020] In some specific implementations, the rotary spray stirring desulfurization includes using an inert gas carrying a desulfurizer as a carrier gas for rotary spray stirring desulfurization; the inert gas includes but is not limited to nitrogen and / or argon, and the present application has no special requirements for the selection of inert gas. In some specific implementations, the desulfurizer includes but is not limited to passivated metal magnesium powder and / or passivated lime, and the present application has no special requirements for the selection of desulfurizer. In some specific implementations, the desulfurizer includes passivated metal magnesium powder and passivated lime, and the mass ratio of the passivated metal magnesium powder to the passivated lime is (3-5):1, which can be 3:1, 3.5:1, 4:1, 4.5:1, 5:1, and preferably 3:1. In some specific implementations, the powder-gas ratio of the desulfurizer to the carrier gas is 20kg / m 3 Up to 40kg / m 3 , can be 20kg / m 3 , 22kg / m 3 , 24kg / m 3 , 26kg / m 3 , 28kg / m 3 、30kg / m 3 、32kg / m 3 、34kg / m3 、36kg / m 3 、38kg / m 3 , 40kg / m 3 .

[0021] In some specific implementations, the injection velocity V of the rare gas carrying the desulfurizer is determined according to the following formula:

[0022] V=(S 初 -S 终 )×D×(24 / 32)÷0.6÷T;

[0023] Among them S 初 is the sulfur content of semi-steel before desulfurization / %; S 终 is the sulfur content required to reach the end point of desulfurization (%); D is the semi-steel charge (kg); T is the desulfurization time (min); (32 / 24) is the magnesium metal demand for the desulfurization process calculated based on Mg+S=MgS, kg; and 0.6 is the utilization rate of magnesium powder in the desulfurization process.

[0024] The rotary jet agitation desulfurization process also includes desulfurization slag treatment, which includes slag skimming and / or slag scooping. After the spraying is complete, the powder spraying is stopped after the nozzle of the gun body clears the liquid surface. After the spray agitation desulfurization is completed, the desulfurization slag in the tank is removed by skimming or scooping to prevent sulfur reversion during subsequent production processes.

[0025] In some specific implementations, the desulfurization rotary stirring lance includes a single-layer stirring blade lance or a multi-layer stirring blade lance. The spray port of the desulfurization rotary stirring lance can be located on the blade, at the end of the stirring shaft, or between the stirring blades. The spray port and the powder delivery pipe form a Y-shaped or T-shaped arrangement. In some specific implementations, the number of stirring blades of the single-layer stirring blade lance is 2 to 4, and the number of layers of the multi-layer stirring blade lance is 2 to 4.

[0026] The desulfurization method described in the present application increases the service life of the rotary blowing and stirring spray gun from about 1000 minutes to more than 1500 minutes, that is, within 1500 minutes, there is no perforation in the gun body, no cracks in the gun body, the diameter of the thinnest part of the gun body is more than 60% of that before use, and the blade wear is only 30% of that before use. The average service life of the rotary blowing and stirring spray gun using conventional usage methods is 980 minutes. The desulfurization method can effectively reduce the sticking of slag in the spray gun, the peeling of refractory materials, and the erosion caused by the shaking of the spray gun, and effectively increase the service life of the rotary blowing and stirring desulfurization spray gun. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic diagram of the structure of the desulfurization rotary stirring spray gun used in Example 1 of the present application. DETAILED DESCRIPTION

[0028] It should be understood that the expression "one or more of" includes individually each of the items recited after the expression and various combinations of two or more of the recited items, unless otherwise apparent from the context and usage. The expression "and / or" in conjunction with three or more recited items should be understood to have the same meaning, unless otherwise apparent from the context.

[0029] The terms "comprising", "having" or "containing", including their grammatical synonyms, should generally be understood as open and non-restrictive, e.g., not excluding other unrecited elements or steps, unless otherwise specifically stated or understood from the context.

[0030] It should be understood that the order of steps or the order in which certain actions are performed is not important as long as the application remains operable. Additionally, two or more steps or actions may be performed simultaneously.

[0031] The use of any and all examples or exemplary language such as "for example" or "including" herein is intended only to better illustrate the present application and does not limit the scope of the present application. No language in this specification should be construed as indicating any non-claimed element is essential to the practice of the present application.

[0032] In addition, the numerical ranges and parameters used to define this application are approximate values. The relevant numerical values in the specific examples have been presented as accurately as possible. However, any numerical value inherently inevitably contains standard deviations due to individual testing methods. Therefore, unless otherwise expressly stated, all ranges, amounts, values, and percentages used in this disclosure should be understood to be modified by the word "about." As used herein, "about" generally means that the actual value is within plus or minus 10%, 5%, 1%, or 0.5% of a particular value or range.

[0033] A desulfurization method for increasing the service life of a desulfurization rotary stirring spray gun, comprising:

[0034] The semi-steel after vanadium extraction is subjected to rotary spray stirring desulfurization, and the desulfurization time is T;

[0035] During the desulfurization period of 0 to 1 / 4T, the desulfurization rotary stirring lance is inserted below the half-steel ladle liquid level and 20% to 30% of the molten pool depth, with a rotation speed of 30 to 50 r / min;

[0036] During the desulfurization period of 1 / 4T to 1 / 2T, insert the desulfurization rotary stirring lance below the half-steel ladle liquid level and 30% to 60% of the molten pool depth, with a rotation speed of 60 to 90 r / min;

[0037] During the desulfurization period from 1 / 2T to 3 / 4T, insert the desulfurization rotary stirring lance below the half-steel ladle level and at 60% to 80% of the molten pool depth, with a rotation speed of 90 to 120 r / min.

[0038] During the desulfurization period from 3 / 4T to the end, the desulfurization rotary stirring lance is inserted below the liquid level of the semi-steel ladle and 50% to 70% of the molten pool depth, with a rotation speed of 80 to 100 r / min.

[0039] The structural diagram of the desulfurization rotary stirring spray gun used in this application is as follows Figure 1 As shown, 1 is the feed pipe interface, 2 is the spray gun body, 3 is the stirring shaft, 4 is the stirring paddle, and 5 is the spray hole.

[0040] The desulfurization method described in the present application increases the service life of the rotary blowing and stirring spray gun from about 1000 minutes to more than 1500 minutes, that is, within 1500 minutes, there is no perforation in the gun body, no cracks in the gun body, the diameter of the thinnest part of the gun body is more than 60% of that before use, and the blade wear is only 30% of that before use. The average service life of the rotary blowing and stirring spray gun using conventional usage methods is 980 minutes. The desulfurization method can effectively reduce the sticking of slag in the spray gun, the peeling of refractory materials, and the erosion caused by the shaking of the spray gun, and effectively increase the service life of the rotary blowing and stirring desulfurization spray gun.

[0041] The present application is further described below with reference to the following examples. The scope of protection of the present application is not limited by the following examples.

[0042] Example 1

[0043] This embodiment provides a desulfurization method for increasing the service life of a desulfurization rotary stirring lance, comprising:

[0044] After the molten iron enters the steel plant, it is first subjected to a converter vanadium extraction process. After the vanadium extraction is completed, 220 tons of semi-steel are poured into a semi-steel tank, and the semi-steel is subjected to a rotary spray stirring desulfurization process (the sulfur content of the semi-steel before desulfurization is 0.120%, and the sulfur content required to be reached at the end of desulfurization is 0.005%). The desulfurization time T = (0.120% - 0.005%) / 0.004% / min = 28.5 min; the magnesium powder injection speed V = (0.120% - 0.005%) × 220 tons × (24 / 32) ÷ 0.6 ÷ 28.5 = 11.09 kg / min; the desulfurization process uses argon and nitrogen as carrier gases, passivated metal magnesium powder and passivated lime as desulfurizers, wherein the ratio of passivated lime to metal magnesium powder is 3:1, and the dosage ratio of desulfurizer to carrier gas (powder-gas ratio) is 30 kg / m 3 The semi-steel desulfurization is controlled in stages according to the desulfurization cycle, as follows:

[0045] During the desulfurization time of 0 to 7 minutes, insert the desulfurization rotary stirring lance below the half-steel ladle liquid level and 30% of the molten pool depth at a rotation speed of 50r / min, and ensure that the powder gas is blown out normally before the nozzle is inserted into the liquid surface; the lance insertion depth refers to the distance between the lowest end of the lance and the upper surface of the molten steel;

[0046] During the desulfurization period of 7 to 14 minutes, the desulfurization rotary stirring lance is inserted below the half-steel ladle liquid level and 60% of the molten pool depth, with a rotation speed of 90 r / min;

[0047] During the desulfurization period of 14 to 21 minutes, the desulfurization rotary stirring lance is inserted below the half-steel ladle liquid level and 80% of the molten pool depth, with a rotation speed of 120 r / min;

[0048] During the desulfurization period from 21 minutes to the end, the desulfurization rotary stirring lance is inserted below the liquid level of the semi-steel ladle and 70% of the molten pool depth, with a rotation speed of 100r / min.

[0049] After the spraying is completed, the spraying of powder is stopped after the spray hole of the gun body leaves the liquid surface. After the spraying and stirring desulfurization is completed, the desulfurization slag in the tank is removed by scraping or scooping to prevent the sulfur from returning during the subsequent production process. The sulfur content of the semi-steel after desulfurization is 0.002%. The structural diagram of the desulfurization rotary stirring spray gun used in this embodiment is as follows Figure 1 shown.

[0050] After 61 continuous furnaces of production, the spray gun was offline. The reason for offline was that the blade wear exceeded 40%, and the cumulative usage time was 1586 minutes.

[0051] Example 2

[0052] This embodiment provides a desulfurization method for increasing the service life of a desulfurization rotary stirring lance, comprising:

[0053] After the molten iron enters the steel plant, it is first subjected to converter vanadium extraction. After the vanadium extraction is completed, 120t of semi-steel is poured into the semi-steel tank for rotary spray stirring desulfurization (the sulfur content of the semi-steel before desulfurization is 0.100%, and the sulfur content required to be reached at the end of desulfurization is 0.003%). The desulfurization time T = (0.100% - 0.003%) / 0.003% / min = 32.3min; the magnesium powder spraying speed V = (0.100% - 0.003%) × 120t × (24 / 32) ÷ 0.6 ÷ 32.3 = 4.5kg / min. The desulfurization process uses argon and nitrogen as carrier gases, passivated metal magnesium powder and passivated lime as desulfurizers, where the ratio of passivated lime to metal magnesium powder is 5:1, and the dosage ratio of desulfurizer to carrier gas (powder-gas ratio) is 40kg / m 3 The semi-steel desulfurization is controlled in stages according to the desulfurization cycle, as follows:

[0054] During the desulfurization time of 0 to 8 minutes, insert the desulfurization rotary stirring lance below the half-steel ladle liquid level and 20% of the molten pool depth at a rotation speed of 40r / min, and ensure that the powder gas is blown out normally before the nozzle is inserted into the liquid surface; the lance insertion depth refers to the distance between the lowest end of the lance and the upper surface of the molten steel;

[0055] During the desulfurization period of 8 to 16 minutes, the desulfurization rotary stirring lance is inserted below the half-steel ladle liquid level and 30% of the molten pool depth, with a rotation speed of 70 r / min;

[0056] During the desulfurization period of 16 to 24 minutes, the desulfurization rotary stirring lance is inserted below the half-steel ladle liquid level and 60% of the molten pool depth, with a rotation speed of 100 r / min;

[0057] During the desulfurization period from 24 minutes to the end, the desulfurization rotating stirring spray gun is inserted below the liquid level of the semi-steel ladle and 50% of the molten pool depth, with a rotation speed of 90r / min; after the spraying is completed, the powder spraying is stopped after the spray hole of the gun body leaves the liquid surface.

[0058] After the spraying is completed, the powder spraying is stopped after the nozzle of the gun body leaves the liquid surface. After the spraying and stirring desulfurization is completed, the desulfurization slag in the tank is removed by slag scraping or slag scooping to prevent the return of sulfur in the subsequent production process. The sulfur content of the semi-steel after desulfurization is 0.0015%.

[0059] After 63 batches of continuous production using this process, the spray gun was offline due to blade wear exceeding 37% and a cumulative usage time of 1703 minutes.

[0060] Example 3

[0061] This embodiment provides a desulfurization method for increasing the service life of a desulfurization rotary stirring lance, comprising:

[0062] After the molten iron enters the steel plant, it is first subjected to converter vanadium extraction. After the vanadium extraction is completed, 80 tons of semi-steel are poured into the semi-steel tank for rotary spray stirring desulfurization (the sulfur content of the semi-steel before desulfurization is 0.090%, and the sulfur content required to be reached at the end of desulfurization is 0.010%). The desulfurization time T = (0.090% - 0.010%) / 0.0025% / min = 32 minutes; the magnesium powder spraying speed V = (0.090% - 0.010%) × 80 tons × (24 / 32) ÷ 0.6 ÷ 32 = 2.5 kg / min. The desulfurization process uses argon and nitrogen as carrier gases, passivated metal magnesium powder and passivated lime as desulfurizers, where the ratio of passivated lime to metal magnesium powder is 4:1, and the ratio of desulfurizer to carrier gas (powder-gas ratio) is 20 kg / m 3 The semi-steel desulfurization is controlled in stages according to the desulfurization cycle, as follows:

[0063] During the desulfurization time of 0 to 8 minutes, insert the desulfurization rotary stirring lance below the half-steel ladle liquid level and 25% of the molten pool depth at a rotation speed of 30r / min, and ensure that the powder gas is blown out normally before the nozzle is inserted into the liquid surface; the lance insertion depth refers to the distance between the lowest end of the lance and the upper surface of the molten steel;

[0064] During the desulfurization period of 8 to 16 minutes, the desulfurization rotary stirring lance is inserted below the half-steel ladle liquid level and 40% of the molten pool depth, with a rotation speed of 60 r / min;

[0065] During the desulfurization period of 16 to 24 minutes, the desulfurization rotary stirring lance is inserted below the half-steel ladle liquid level and 70% of the molten pool depth, with a rotation speed of 90 r / min;

[0066] During the desulfurization period from 24 minutes to the end, the desulfurization rotating stirring spray gun is inserted below the liquid level of the semi-steel ladle and 60% of the molten pool depth, with a rotation speed of 80r / min; after the spraying is completed, the powder spraying is stopped after the spray hole of the gun body leaves the liquid surface.

[0067] After the spraying is completed, the powder spraying is stopped after the nozzle of the gun body leaves the liquid surface. After the spraying and stirring desulfurization is completed, the desulfurization slag in the tank is removed by slag scraping or slag scooping to prevent the return of sulfur in the subsequent production process. The sulfur content of the semi-steel after desulfurization is 0.006%.

[0068] After 67 batches of continuous production using this process, the spray gun was offline due to blade wear exceeding 35%, and the cumulative usage time was 1977 minutes.

[0069] Comparative Example 1

[0070] This comparative example provides a desulfurization method for increasing the service life of a desulfurization rotary stirring spray gun, which differs from Example 1 in that:

[0071] During the desulfurization time of 0 to 6.5 minutes, insert the desulfurization rotary stirring lance below the half-steel ladle liquid level and 15% of the molten pool depth at a rotation speed of 25 r / min, and ensure that the powder gas is blown out normally before the nozzle is inserted into the liquid surface; the lance insertion depth refers to the distance between the lowest end of the lance and the upper surface of the molten steel;

[0072] When the desulfurization time is between 6.5 and 13 minutes, the desulfurization rotary stirring lance is inserted below the half-steel ladle liquid level and 70% of the molten pool depth, with a rotation speed of 40 r / min;

[0073] During the desulfurization period of 13 to 19.5 minutes, the desulfurization rotary stirring lance is inserted below the half-steel ladle liquid level and 90% of the molten pool depth, with a rotation speed of 60 r / min;

[0074] During the desulfurization time from 19.5min to the end, the desulfurization rotating stirring spray gun is inserted below the liquid level of the semi-steel ladle and 80% of the molten pool depth, with a rotation speed of 70r / min; after the spraying is completed, the powder spraying is stopped after the spray hole of the gun body leaves the liquid surface.

[0075] After the spraying is completed, the powder spraying is stopped after the nozzle of the gun body leaves the liquid surface. After the spraying and stirring desulfurization is completed, the desulfurization slag in the tank is removed by slag scraping or slag scooping to prevent the return of sulfur in the subsequent production process. The sulfur content of the semi-steel after desulfurization is 0.003%.

[0076] After 61 batches of continuous production using this process, the spray gun was offline due to blade wear exceeding 51% and nozzle blockage. The cumulative usage time was 1412 minutes.

[0077] Comparative Example 2

[0078] This comparative example provides a method for extending the life of a desulfurization rotary agitation lance. This method differs from Example 1 in that the lance was fully inserted below the semi-ladle level and at 85% of the molten pool depth, rotating at a speed of 60 rpm. The lance was removed from production after 61 continuous heats due to a perforation in the lance body, resulting in a cumulative service life of 1,389 minutes.

[0079] Comparative Example 3

[0080] This comparative example provides a desulfurization method for increasing the service life of a desulfurization rotary stirring spray gun, which differs from Example 2 in that:

[0081] During the desulfurization period from 24 minutes to the end, the desulfurization rotary stirring lance is inserted below the liquid level of the semi-steel ladle and 60% of the molten pool depth, with a rotation speed of 100r / min.

[0082] After 57 batches of continuous production using this process, the spray gun was offline due to perforation and leakage of the gun body. The cumulative usage time was 1513 minutes.

[0083] Comparative Example 4

[0084] This comparative example provides a desulfurization method for increasing the service life of a desulfurization rotary stirring spray gun, which differs from Example 2 in that:

[0085] During the desulfurization period of 16 to 24 minutes, the desulfurization rotary stirring lance is inserted below the half-steel ladle liquid level and 60% of the molten pool depth, with a rotation speed of 90 r / min;

[0086] During the desulfurization period from 24 minutes to the end, the desulfurization rotary stirring spray gun is inserted below the liquid level of the semi-steel ladle and 72% of the molten pool depth, with a rotation speed of 100r / min; after the spraying is completed, the powder spraying is stopped after the spray hole of the gun body leaves the liquid surface.

[0087] After 63 batches of continuous production using this process, the spray gun was offline due to blade wear exceeding 49% and a cumulative usage time of 1461 minutes.

[0088] Comparative Example 5

[0089] This comparative example provides a desulfurization method for increasing the service life of a desulfurization rotary stirring spray gun, which differs from Example 3 in that:

[0090] The semi-steel desulfurization is controlled in stages according to the desulfurization cycle, as follows:

[0091] During the desulfurization time of 0 to 8 minutes, insert the desulfurization rotary stirring spray gun below the liquid level of the semi-steel ladle and 25% of the molten pool depth, with a rotation speed of 28r / min, and ensure that the powder gas is blown out normally before the spray hole is inserted into the liquid surface;

[0092] During the desulfurization period of 8 to 16 minutes, the desulfurization rotary stirring lance is inserted below the half-steel ladle liquid level and 40% of the molten pool depth, with a rotation speed of 58 r / min;

[0093] During the desulfurization period of 16 to 24 minutes, the desulfurization rotary stirring lance is inserted below the half-steel ladle liquid level and 70% of the molten pool depth, with a rotation speed of 88 r / min;

[0094] During the desulfurization period from 24 minutes to the end, the desulfurization rotary stirring spray gun is inserted below the liquid level of the semi-steel ladle and 60% of the molten pool depth, with a rotation speed of 78r / min; after the spraying is completed, the powder spraying is stopped after the spray hole of the gun body leaves the liquid surface.

[0095] After 67 batches of continuous production using this process, the spray gun was offline due to blade wear exceeding 57%, and the cumulative usage time was 1897 minutes.

[0096] The molten pool depth, rotation speed, and corresponding cumulative usage time and wear amount in the embodiments and comparative examples are shown in Table 1.

[0097] Table 1

[0098]

[0099] The above is only a preferred specific implementation method of the present application, but the scope of protection of the present application is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes based on the technical solution and application concept of the present application within the technical scope disclosed in the present application, and they should be covered by the scope of protection of the present application.

Claims

1. A desulfurization method for increasing the service life of a desulfurization rotary stirring spray gun, characterized in that: include: The semi-steel after vanadium extraction is subjected to rotary spray stirring desulfurization, and the desulfurization time is T; During the desulfurization period of 0 to 1 / 4T, the desulfurization rotary stirring lance is inserted below the half-steel ladle liquid level and 20% to 30% of the molten pool depth, with a rotation speed of 30 to 50 r / min; During the desulfurization period of 1 / 4T to 1 / 2T, insert the desulfurization rotary stirring lance below the half-steel ladle liquid level and 30% to 60% of the molten pool depth, with a rotation speed of 60 to 90 r / min; During the desulfurization period from 1 / 2T to 3 / 4T, insert the desulfurization rotary stirring lance below the half-steel ladle level and at 60% to 80% of the molten pool depth, with a rotation speed of 90 to 120 r / min. During the desulfurization period from 3 / 4T to the end, the desulfurization rotary stirring lance is inserted below the liquid level of the semi-steel ladle and 50% to 70% of the molten pool depth, with a rotation speed of 80 to 100 r / min.

2. The desulfurization method according to claim 1, characterized in that: The desulfurization time T is determined according to the following formula: T=(S 初 -S 终 ) / S s ; Among them, S 初 is the sulfur content of semi-steel before desulfurization; S 终 S is the sulfur content required to be achieved at the end of desulfurization; s is the sulfur removal rate of semi-steel.

3. The desulfurization method according to claim 2, characterized in that: The sulfur content of the semi-steel before desulfurization is 0.12%≤S 初 When the content is ≤1%, the sulfur removal rate of semi-steel is 0.0035% / min to 0.0040% / min; The sulfur content of the semi-steel before desulfurization is 0.1%≤S 初 When the sulfur content is less than 0.12%, the sulfur removal rate of semi-steel is 0.0030% / min to 0.0035% / min; The sulfur content of the semi-steel before desulfurization is 0.0001%≤S 初 When the sulfur content is less than 0.1%, the sulfur removal rate of semi-steel is 0.0025% / min to 0.0035% / min.

4. The desulfurization method according to claim 1, characterized in that: The rotary spray stirring desulfurization includes using an inert gas carrying a desulfurizer as a carrier gas to perform rotary spray stirring desulfurization; the inert gas includes nitrogen and / or argon.

5. The desulfurization method according to claim 4, characterized in that: The desulfurizing agent includes passivated metal magnesium powder and / or passivated lime.

6. The desulfurization method according to claim 5, characterized in that: The desulfurizer includes passivation metal magnesium powder and passivation lime, and the mass ratio of the passivation metal magnesium powder to the passivation lime is (3-5):

1.

7. The desulfurization method according to claim 4, characterized in that: The powder-gas ratio of the desulfurizer to the carrier gas is 20 kg / m 3 Up to 40kg / m 3 .

8. The desulfurization method according to claim 4, characterized in that: The injection velocity V of the rare gas carrying the desulfurizer is determined according to the following formula: V=(S 初 -S 终 )×D×(24 / 32)÷0.6÷T; Among them S 初 is the sulfur content of semi-steel before desulfurization; S 终 is the sulfur content required to be reached at the end of desulfurization; D is the semi-steel loading amount; T is the desulfurization time.

9. The desulfurization method according to claim 1, characterized in that: The rotary jet stirring desulfurization further includes desulfurization slag treatment after the desulfurization slag treatment; the desulfurization slag treatment includes slag skimming and / or slag scooping.

10. The desulfurization method according to claim 1, characterized in that: The desulfurization rotary stirring spray gun includes a single-layer stirring blade spray gun or a multi-layer stirring blade spray gun. The number of stirring blades of the single-layer stirring blade spray gun is 2 to 4. The blowing port of the desulfurization rotary stirring spray gun can be set on the blade, at the end of the stirring shaft or between the stirring blades. The blowing port and the powder conveying pipe are arranged in a Y-shape or T-shape.

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