Self-corrosion type semi-steel desulfurization spray gun and application thereof

Abstract

The invention discloses a self-corrosion type semi-steel desulfurization spray gun and application thereof, and belongs to the field of steel smelting. The self-corrosion type semi-steel desulfurization spray gun comprises a spray gun body and a refractory material layer arranged outside the spray gun body, the spray gun body comprises a spray gun inner pipe with two spray gun holes, the spray gun inner pipe is arranged in the spray gun body in the length direction of the spray gun body, one end of each spray gun hole is connected with the spray gun inner pipe, and the other end of each spray gun hole is connected with the refractory material layer. The connecting angle between each spray gun hole and the spray gun inner pipe is 90 degrees, the included angle between the two spray gun holes is 180 degrees, and the two spray gun holes are formed in the refractory material layer in the radial direction of the refractory material layer. The spray gun slag line part of the refractory material layer is formed by pouring aluminum oxide and carbon powder, and the mass ratio of the aluminum oxide is more than 80%. By designing the self-corrosion type refractory material and the like, a liquid product is slowly formed between the gun body and slag and falls off, slag adhesion is prevented, and therefore the service life of the gun body is prolonged.

Description

Technical Field

[0001] The invention belongs to the field of steel smelting, and in particular relates to a self-etching semi-steel desulfurization spray gun and application thereof. Background Art

[0002] Hot metal desulfurization technology has been used outside the furnace since the 1930s, flourished in the 1960s, and is widely used in actual production today. There are a wide variety of treatment processes, encompassing approximately six categories and 16 different methods. The following processes have been invented: shaking methods, including the Swedish unidirectional eccentric shaking ladle method and the reversible rotating DM shaking ladle method developed by Kawasaki Iron Works in Kobe, Japan; mechanical stirring methods, including the German DO (Demag-Ostberg) method, RS (Rheinstahl) method, and Herschel method, and the Japanese methods of Nippon Steel's KR (Kambara Reactor) method and Chiba's NP method; air-blowing stirring methods, including Nippon Steel's PDS (bottom spray) method and CLDS (top spray) method; bell-jar pressure-injection methods, primarily the magnesia-coke method developed by Janes Laughlin in the United States and other magnesium-based desulfurization methods; injection methods, including the German Thyssen ATH (oblique lance) method and Nippon Steel's TDS (top spray) method; and continuous desulfurization in the furnace ditch.

[0003] Currently, although most steel mills have adopted the KR desulfurization method, some still use the injection desulfurization process. The injection method generally uses nitrogen (N2) as a carrier gas to spray powdered desulfurizers (such as CaO and Mg) into the molten iron through a spray gun. The carrier gas also stirs the molten iron, ensuring that the injection gas, desulfurizer, and molten iron are fully mixed to achieve desulfurization. The specific injection methods include single-spray granular magnesium, single-spray lime, and combined spraying. Their advantages are low equipment cost, flexible operation, short spraying time, and small temperature drop of the molten iron. The structure of the existing spray gun mainly includes: an inverted T-shaped spray hole, an inner nozzle directly connected to the bottom of the gun body, and an inverted Y-shaped spray hole.

[0004] After pretreatment such as vanadium extraction, blast furnace molten iron becomes semi-steel. Smelters using vanadium-titanium iron ore as raw material face challenges controlling the sulfur content of semi-steel. Due to the structure and refractory material of existing spray guns for desulfurization of semi-steel, slag accumulates near the nozzle during the desulfurization process, even causing nozzle blockage. Furthermore, desulfurization slag adheres to the lance body at the slag line at the top, gradually increasing its weight and causing significant vibration during the desulfurization process, posing a safety hazard to the lance lifting mechanism. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a self-etching semi-steel desulfurization spray gun and its application. The spray gun provided by the present invention is mainly used for semi-steel desulfurization, which can prevent the adhesion of semi-steel desulfurization slag, thereby increasing the life of the gun body.

[0006] The present invention provides a self-etching semi-steel desulfurization spray gun, comprising a spray gun body and a refractory material layer arranged on the outside of the spray gun body, the spray gun body comprising a spray gun inner tube having two spray gun holes, the spray gun inner tube being arranged in the spray gun body along the length direction of the spray gun body, wherein one end of the two spray gun holes is connected to the spray gun inner tube, the angle at which each spray gun hole is connected to the spray gun inner tube is 90°, the two spray gun holes are 180° apart from each other, and the two spray gun holes are respectively formed in the refractory material layer along the radial direction of the refractory material layer; the spray gun slag line portion of the refractory material layer is formed by casting alumina and carbon powder, and the mass proportion of the alumina is more than 80%.

[0007] In an embodiment of the present invention, the two spray gun holes are located at the bottom end of the spray gun body, and the straight-line distance between the spray gun slag line portion of the refractory material layer and the top end of the spray gun body is within 1000 mm; the spray gun slag line portion of the refractory material layer is formed by casting alumina particles and carbon powder, and the mass ratio of the alumina particles to the carbon powder is 80% to 90%: 10% to 20%, and the particle size of the alumina particles is less than 3 mm.

[0008] In an embodiment of the present invention, the straight-line distance between the two spray gun holes and the bottom of the spray gun body is 200 to 800 mm, and the bottom end of the refractory material layer spray gun is formed by casting alumina particles, silica particles and carbon powder. The mass ratio of the alumina particles, silica particles and carbon powder is 60% to 70%: 20% to 30%: 5 to 10%; the particle size of the silica particles is less than 2 mm.

[0009] In an embodiment of the present invention, the refractory material layer outside the slag line of the spray gun and the bottom end of the spray gun is formed by casting an alumina-silicon oxide refractory material.

[0010] In an embodiment of the present invention, a parallel oblique thorn-type skeleton connected to the outer wall of the inner tube of the spray gun is provided in the refractory material layer.

[0011] In an embodiment of the present invention, the self-etching semi-steel desulfurization lance further comprises: a number of spray hoses equal to the number of the lance inner tubes, and each spray hose connects an air injection device with one end of a lance inner tube.

[0012] Furthermore, the present invention provides the application of the aforementioned self-etching semi-steel desulfurization lance in semi-steel desulfurization.

[0013] In an embodiment of the present invention, the gas containing the desulfurizing agent is sprayed into the semi-steel molten metal through the inner tube of the spray gun of the self-etching semi-steel desulfurization spray gun.

[0014] In an embodiment of the present invention, the pressure of the blowing gas in the inner tube of the spray gun is set to 300-600 kPa.

[0015] In an embodiment of the present invention, after the spraying is completed, the self-etching semi-steel desulfurization lance is lifted, and the pressure supply to the lance hole exposing the semi-steel molten metal is stopped.

[0016] Existing lance designs often experience slag accumulation in semi-steel desulfurization applications. This is primarily due to the current lance injection pressure of only 300-500 kPa. Under the pressure of the molten iron, the desulfurizer is squeezed into a low-temperature zone near the lance body, causing the molten iron temperature to drop. This desulfurizer then forms nodules with CaO and other substances, which adhere to the lance body and cause slag accumulation. To address these issues, lance oscillation and spray uniformity require prioritizing the design of the lance structure and device.

[0017] The present invention provides a self-etching semi-steel desulfurization spray gun, comprising a spray gun body and a refractory material layer arranged on the outside of the spray gun body, the spray gun body comprising a spray gun inner tube and two spray gun holes, and the overall structure has an "inverted T-shaped" spray gun hole. At the same time, the spray gun slag line portion of the refractory material layer of the present invention is formed by casting alumina and carbon powder, and the mass proportion of the alumina is more than 80%. The present invention uses high-melting-point pure oxides and carbon powder to cast refractory material layers in areas prone to slag accumulation. First, it can weaken the thermodynamic conditions for the reaction of the desulfurizer with it; second, it can reduce the wetting angle between the refractory material and the molten iron, reducing iron sticking; third, during use, carbon powder adds carbon to the molten iron, causing the refractory material to loosen and peel off, reducing the accumulation of slag, and thereby achieving an extension of the service life. The present invention is based on the reaction between slag and refractory material as the basic starting point. By designing a self-etching refractory material, a liquid product is slowly formed and falls off between the gun body and the slag, preventing the adhesion of slag, thereby improving the service life of the gun body. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic structural diagram of a self-etching semi-steel desulfurization lance according to some embodiments of the present invention. DETAILED DESCRIPTION

[0019] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, the technical solutions of the present invention are described in detail below in conjunction with specific embodiments. The described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0020] The present invention provides a self-etching semi-steel desulfurization spray gun, comprising a spray gun body and a refractory material layer arranged on the outside of the spray gun body, the spray gun body comprising a spray gun inner tube having two spray gun holes, the spray gun inner tube being arranged in the spray gun body along the length direction of the spray gun body, wherein one end of the two spray gun holes are connected to the spray gun inner tube, the angle at which each spray gun hole is connected to the spray gun inner tube is 90°, the two spray gun holes are 180° apart from each other, and the two spray gun holes are respectively formed in the refractory material layer along the radial direction of the refractory material layer; the spray gun slag line portion of the refractory material layer is formed by casting alumina and carbon powder, and the mass proportion of the alumina is more than 80%.

[0021] The spray gun provided by the invention is mainly used for semi-steel desulfurization and can prevent the adhesion of semi-steel desulfurization slag, thereby increasing the service life of the gun body.

[0022] See also Figure 1 , Figure 1 The structure diagram of the self-etching semi-steel desulfurization lance of some embodiments of the present invention is shown in FIG1 , wherein 1 is the inner tube of the lance, 2 is the refractory material layer, 3 is the parallel oblique thorn frame, and 4 is the lance hole.

[0023] The self-etching semi-steel desulfurization spray gun described in an embodiment of the present invention includes a spray gun body, which includes a spray gun inner tube 1, which is a metal inner tube with two spray gun holes 4; and the spray gun inner tube 4 is arranged at the center of the spray gun body along the length direction of the spray gun body, for spraying powder desulfurizer and gas, etc.

[0024] In this embodiment of the present invention, one end of each of the two lance holes 4 is connected to the lance inner tube 1. Each lance hole 4 is connected to the lance inner tube 1 at an angle of 90°, and the two lance holes 4 are 180° apart. This embodiment of the present invention features an "inverted T-shaped" double-hole semi-steel desulfurization lance. The lance holes 4 are perpendicular to the lance inner tube 1. This allows for separation of the desulfurizer and carrier gas at low injection pressures, thereby improving the desulfurization effect.

[0025] The self-etching semi-steel desulfurization lance described in the embodiment of the present invention includes a refractory layer 2, and the lance body is arranged inside the refractory layer 2; two lance holes 4 are symmetrically distributed in the refractory layer 2 along the radial direction of the refractory layer 2.

[0026] The refractory layer 2 is generally formed by covering the inner tube 1 of the spray gun with cast refractory material; the slag line of the spray gun is formed by casting alumina and carbon powder, and the mass proportion of the alumina is more than 80%, for example, 80-90%. Unlike molten iron desulfurization, semi-steel desulfurization has a high melting point because the main components of the desulfurization slag are MgO, CaO and a small amount of other substances. This easily lowers the temperature of the molten iron, resulting in the problem of slag-metal mixture sticking to the spray gun at the slag-metal interface. In the embodiment of the present invention, specific refractory materials are used to promote the formation of low-point substances between the spray gun and the desulfurization slag in the areas where slag is easily accumulated in the refractory layer 2, making it difficult for the mixture to stick to the spray gun, thereby reducing the possibility of the spray gun forming an umbrella-shaped adhesive, thereby increasing the life of the spray gun.

[0027] Specifically, the slag line position of the spray gun (the area 0 to 1000 mm from the top of the spray gun, such as Figure 1 As shown in the figure), Al2O3 particles with a particle size of 0 to 3 mm and carbon powder are used as refractory materials for casting; the mass ratio of the Al2O3 particles to the carbon powder is 80% to 90%:10% to 20%.

[0028] Furthermore, the bottom end of the spray gun according to the embodiment of the present invention is also as Figure 1 As shown (the end of the spray gun hole, 200 to 800 mm from the bottom), Al2O3 particles with a particle size of 0 to 3 mm, SiO2 particles with a particle size of 0 to 2 mm and carbon powder are used as refractory materials for casting, and the ratio of the three is preferably 60% to 70%: 20% to 30%: 5 to 10%.

[0029] In addition, the rest of the spray gun is still cast with traditional spray gun refractory materials (referred to as refractory materials). In some embodiments, the refractory material layer 2 is cast with alumina-silicon oxide refractory materials outside the spray gun slag line and the bottom of the spray gun, which is beneficial to the long life of the spray gun and reducing costs. The alumina-silicon oxide refractory materials include ceramic main raw materials and micropowder / fiber auxiliary materials, usually with fused mullite, andalusite, corundum and other ceramic main raw materials, combined with Al2O3 micropowder, SiO2 micropowder, steel fiber and other common auxiliary materials; the raw material ratio is conventional. For example, the alumina-silicon oxide refractory materials: fused mullite, andalusite, corundum as the main raw materials, the mass ratio of the three is 2:2:1, combined with Al2O3 micropowder, SiO2 micropowder, steel fiber, the mass ratio of the three is 1:1:1.

[0030] Preferably, the refractory layer 2 may be provided with a parallel oblique thorn-shaped skeleton 3 (also known as a fishbone-shaped skeleton) connected to the outer wall of the spray gun inner tube 1. The skeleton serves to improve the stability and strength of the refractory layer; multiple steel bars of φ5 to 10 mm can be welded to the outside of the inner tube, and the angle between the steel bars and the inner tube is generally 10 to 30 degrees.

[0031] In some exemplary embodiments, the diameter ratio of the lance inner tube to the lance hole may be 20-30 mm:5-15 mm; and the thickness of the refractory material layer may be 50-150 mm.

[0032] In an embodiment of the present invention, the self-etching semi-steel desulfurization lance further comprises: a number of spray hoses equal to the number of the lance inner tubes, and each spray hose connects a conventional jet device with one end of a lance inner tube.

[0033] Furthermore, the present invention provides the application of the aforementioned self-etching semi-steel desulfurization spray gun in semi-steel desulfurization. In the embodiment of the present invention, gas containing a desulfurizing agent is sprayed into the semi-steel molten metal through the inner tube of the spray gun of the self-etching semi-steel desulfurization spray gun to perform desulfurization treatment.

[0034] After vanadium extraction, molten iron becomes semi-steel, characterized by its carbon content generally less than 3.5% and very low silicon content. Besides the desulfurization spray gun's inherent characteristics, the type of desulfurizer, the desulfurizer ratio in the carrier gas, and the desulfurization spraying process also have a certain impact on the life of the spray gun. In an embodiment of the present invention, the pressure of the spray gas in the inner tube of the spray gun is set to 300-600 kPa, preferably 400-500 kPa.

[0035] Specifically, the desulfurizer used is generally magnesium powder and passivated lime in a mass ratio of 1:3 to 1:5; the carrier gas is generally nitrogen; the injection speed (magnesium powder) can be controlled at 8 to 15 kg / min, and the powder-gas ratio (the ratio of desulfurizer to gas) is preferably 30 to 50 kg / m 3 .

[0036] After the spraying is complete, the self-etching semi-steel desulfurization lance is raised and pressure is stopped at the lance hole where the semi-steel molten metal is exposed. This embodiment improves lance stability during the spraying process. The reaction between the refractory and the desulfurization slag causes the sticking slag to fall off, thereby extending the life of the semi-steel desulfurization lance and maintaining stable equipment operation.

[0037] To further illustrate the present invention, the present invention is described in detail below with reference to the following examples. In the examples, all raw reagents and materials are commercially available, and the experimental methods without specific experimental conditions are conventional methods and conditions well known in the art.

[0038] Example 1

[0039] like Figure 1As shown, the semi-steel desulfurization lance includes: a refractory layer 2 and a lance body arranged inside the refractory layer 2, the lance body including a lance inner tube 1 and two lance holes 4, wherein the lance inner tube 1 is arranged inside the lance body along the length direction of the lance body, one end of the two lance holes 4 are connected to the lance inner tube 1, the lance holes 4 are 90 degrees to the lance inner tube 1, and the two lance holes are 180 degrees apart from each other, and the lance holes 4 are respectively formed in the refractory layer 2 along the radial direction of the refractory layer. The lance is also provided with a fishbone-shaped skeleton 3 (multiple steel bars of φ5-10mm are selected and welded to the outside of the inner tube, and the angle between them and the inner tube is generally 10-30 degrees, the same as in the following embodiments). The diameter of the lance inner tube is 20-30mm, and the diameter of the lance hole is 5-15mm; and the thickness of the refractory layer is 90-100mm.

[0040] The slag line of the spray gun (the area 0-1000mm from the gun tip) is cast with 0-3mm Al2O3 particles and carbon powder as the refractory material, with the Al2O3 particles and carbon powder ratio being 85%:15%. The bottom of the spray gun (the gun hole end, 200-800mm from the bottom) is cast with 0-3mm Al2O3 particles, 0-2mm SiO2 particles, and carbon powder as the refractory material, with the ratio of 70%:20%:10%. The rest of the gun body is still cast with traditional spray gun refractory materials, specifically fused mullite, andalusite, and corundum as the main raw materials, supplemented with Al2O3 micropowder, SiO2 micropowder, and steel fiber, using the conventional raw material ratio (main raw material mass ratio of 2:2:1, supplementary component mass ratio of 1:1:1). In addition, a spray hose is used to connect an air injection device to one end of the inner tube of a spray gun.

[0041] The semi-steel desulfurization method comprises: injecting a gas containing a desulfurizer into the molten metal through the inner tube of the spray gun; the spraying pressure is set to 600kPa. The desulfurizer is magnesium powder and passivation lime in a mass ratio of 1:3, the carrier gas is nitrogen, the spraying speed (magnesium powder) is controlled at 12kg / min, and the powder-gas ratio (ratio of desulfurizer to gas) is 50kg / m 3 During the process of lifting the gun after the spraying is completed, the pressure supply to the gun hole where the molten metal is exposed is stopped.

[0042] The average lifespan of a spray gun is 87 times per gun, with an average usage time of 1,551 minutes. The standard for a spray gun to be discontinued is when the erosion at the slag line (calculated based on the gun diameter) exceeds 40%.

[0043] Example 2

[0044] like Figure 1As shown, the semi-steel desulfurization lance includes: a refractory layer 2 and a lance body disposed inside the refractory layer 2, the lance body including a lance inner tube 1 and two lance holes 4, wherein the lance inner tube 1 is disposed inside the lance body along the length direction of the lance body, one end of each of the two lance holes 4 is connected to the lance inner tube 1, the lance holes 4 are 90 degrees to the lance inner tube 1, and the two lance holes are 180 degrees apart from each other, and the lance holes 4 are respectively formed in the refractory layer 2 along the radial direction of the refractory layer, and a fishbone-shaped skeleton 3 is also provided in the lance. The diameter of the lance inner tube is 20-30 mm, the diameter of the lance holes is 5-15 mm, and the thickness of the refractory layer is 50-60 mm.

[0045] The spray gun slag line (the area 0-1000 mm from the gun top) was cast with 0-3 mm Al2O3 particles and carbon powder as refractory materials, with a ratio of 90%:10%; the spray gun bottom (the gun hole end, 200-800 mm from the bottom) was cast with 0-3 mm Al2O3 particles, 0-2 mm SiO2 particles, and carbon powder as refractory materials, with a ratio of 70%:25%:5%; the remaining parts of the gun body were still cast with conventional spray gun refractory materials (the same as in Example 1). Furthermore, a spray hose was used to connect an air injection device to one end of a spray gun inner tube.

[0046] The semi-steel desulfurization method comprises: injecting a gas containing a desulfurizing agent into the molten metal through the inner tube of the spray gun; the spraying pressure is set to 500kPa. The desulfurizing agent is magnesium powder and passivating lime in a mass ratio of 1:4, the carrier gas is nitrogen, the spraying speed (magnesium powder) is controlled at 15kg / min, and the powder-gas ratio (ratio of desulfurizing agent to gas) is 40kg / m 3 During the process of lifting the gun after the spraying is completed, the pressure supply to the gun hole where the molten metal is exposed is stopped.

[0047] The average life of the spray gun reaches 85 times / piece, and the average usage time is 1568 minutes. The spray gun offline standard: the erosion amount at the slag line position (calculated based on the gun body diameter) is >40%.

[0048] Example 3

[0049] like Figure 1As shown, the semi-steel desulfurization lance includes: a refractory layer 2 and a lance body disposed inside the refractory layer 2, the lance body including a lance inner tube 1 and two lance holes 4, wherein the lance inner tube 1 is disposed inside the lance body along the length direction of the lance body, one end of each of the two lance holes 4 is connected to the lance inner tube 1, the lance holes 4 are 90 degrees to the lance inner tube 1, and the two lance holes are 180 degrees apart from each other, and the lance holes 4 are respectively formed in the refractory layer 2 along the radial direction of the refractory layer, and a fishbone-shaped skeleton 3 is also provided in the lance. The diameter of the lance inner tube is 20-30 mm, the diameter of the lance holes is 5-15 mm, and the thickness of the refractory layer is 140-150 mm.

[0050] The spray gun slag line (the area 0-1000 mm from the gun top) was cast with 0-3 mm Al2O3 particles and carbon powder as refractory materials, with the ratio of Al2O3 particles to carbon powder being 80%:20%. The spray gun bottom (the gun hole end, the area 200-800 mm from the bottom) was cast with 0-3 mm Al2O3 particles, 0-2 mm SiO2 particles, and carbon powder as refractory materials, with the ratio of 60%:30%:10%. The remaining parts of the gun body were still cast with conventional spray gun refractory materials (the same as in Example 1). Furthermore, a spray hose was used to connect an air injection device to one end of a spray gun inner tube.

[0051] The semi-steel desulfurization method comprises: injecting a gas containing a desulfurizing agent into the molten metal through the inner tube of the spray gun; the spraying pressure is set to 400kPa. The desulfurizing agent is magnesium powder and passivation lime in a mass ratio of 1:5, the carrier gas is nitrogen, the spraying speed (magnesium powder) is controlled at 8kg / min, and the powder-gas ratio (ratio of desulfurizing agent to gas) is 30kg / m 3 During the process of lifting the gun after the spraying is completed, the pressure supply to the gun hole where the molten metal is exposed is stopped.

[0052] The average lifespan of a spray gun is 90 times per gun, with an average usage time of 1,632 minutes. The standard for a spray gun to be discontinued is when the erosion at the slag line (calculated based on the gun diameter) exceeds 40%.

[0053] Comparative Example

[0054] The main structure of the desulfurization lance and the semi-steel desulfurization method are the same as those in Example 1.

[0055] The gun body is cast using traditional spray gun refractory materials (with fused mullite, andalusite, corundum, etc. as main raw materials, combined with common materials such as Al2O3 micropowder, SiO2 micropowder, steel fiber, etc., the same as Example 1); and a spray hose is used to connect an air injection device to one end of an inner tube of a spray gun.

[0056] The average lifespan of a spray gun is 62 times per gun, with an average usage time of 1,187 minutes. The reasons for gun downtime are: 62% due to crusting at the slag line, 27% due to burn-through, 6% due to nozzle blockage, 3% due to gun deformation, and 2% due to gun breakage.

[0057] From the above embodiments, it can be seen that the present invention mainly adopts a semi-steel desulfurization spray gun made of self-etching refractory materials to slowly form and fall off a liquid product between the gun body and the slag, thereby preventing the slag from sticking, thereby increasing the life of the gun body and maintaining stable operation of the equipment.

[0058] The foregoing descriptions of specific exemplary embodiments of the present invention are for purposes of illustration and description. These descriptions are not intended to limit the invention to the precise forms disclosed, and it is apparent that many variations and modifications are possible in light of the foregoing teachings. The exemplary embodiments have been selected and described for the purpose of explaining the specific principles of the invention and their practical application, thereby enabling those skilled in the art to realize and utilize a variety of exemplary embodiments of the invention and various options and modifications. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. A self-etching semi-steel desulfurization spray gun, comprising a spray gun body and a refractory material layer arranged outside the spray gun body, wherein the spray gun body comprises a spray gun inner tube having two spray gun holes, and the spray gun inner tube is arranged in the spray gun body along the length direction of the spray gun body, wherein: One end of the two spray gun holes is connected to the inner tube of the spray gun, and the angle at which each spray gun hole is connected to the inner tube of the spray gun is 90°. The two spray gun holes are 180° apart from each other, and the two spray gun holes are respectively formed in the refractory material layer along the radial direction of the refractory material layer; the spray gun slag line part of the refractory material layer is formed by casting alumina and carbon powder, and the mass of the alumina accounts for more than 80%.

2. The self-etching semi-steel desulfurization spray gun according to claim 1, characterized in that: The two spray gun holes are located at the bottom end of the spray gun body, and the straight-line distance between the spray gun slag line of the refractory material layer and the top of the spray gun body is within 1000mm; the spray gun slag line of the refractory material layer is formed by casting alumina particles and carbon powder, and the mass ratio of the alumina particles to carbon powder is 80% to 90%: 10% to 20%, and the particle size of the alumina particles is less than 3mm.

3. The self-etching semi-steel desulfurization spray gun according to claim 1, characterized in that: The straight-line distance between the two spray gun holes and the bottom of the spray gun body is 200 to 800 mm. The bottom end of the refractory material layer spray gun is formed by casting alumina particles, silica particles and carbon powder. The mass ratio of the alumina particles, silica particles and carbon powder is 60% to 70%: 20% to 30%: 5 to 10%; the particle size of the silica particles is less than 2 mm.

4. The self-etching semi-steel desulfurization spray gun according to any one of claims 1 to 3, characterized in that: The refractory material layer is formed by pouring an alumina-silicon oxide refractory material outside the slag line of the lance and the bottom end of the lance.

5. The self-etching semi-steel desulfurization spray gun according to any one of claims 1 to 3, characterized in that: The refractory material layer is provided with a parallel oblique thorn-type skeleton connected to the outer wall of the inner tube of the spray gun.

6. The self-etching semi-steel desulfurization lance according to any one of claims 1 to 3, characterized in that: The self-etching semi-steel desulfurization lance further comprises: a number of spray hoses equal to the number of the lance inner tubes, and each of the spray hoses connects an injection device with one end of a lance inner tube.

7. Use of the self-etching semi-steel desulfurization spray gun according to any one of claims 1 to 6 in semi-steel desulfurization.

8. The use according to claim 7, characterized in that The gas containing the desulfurizing agent is sprayed into the semi-steel metal liquid through the inner tube of the self-etching semi-steel desulfurization spray gun.

9. The use according to claim 8, characterized in that The pressure of the blowing gas in the inner tube of the spray gun is set to 300-600 kPa.

10. The use according to claim 9, characterized in that After the spraying is completed, the self-etching semi-steel desulfurization spray gun is lifted, and the pressure supply to the spray gun hole where the semi-steel metal liquid is exposed is stopped.

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