Process and device for the production of tin dioxide

Abstract

The application relates to a preparation process and device of tin dioxide. The preparation process of tin dioxide comprises the following steps: melting metal tin to form a first tin liquid, introducing inert gas into the first tin liquid, controlling preset pressure, forming a second tin liquid, performing atomization treatment on the second tin liquid to form tin mist, and performing combustion treatment on the tin mist to generate tin dioxide. The application utilizes the inert gas to generate preset pressure on the tin liquid, and performs atomization treatment and combustion treatment on the tin liquid, so that the yield of tin dioxide is remarkably improved, and the tin dioxide has excellent performance. Meanwhile, a device for executing the preparation process is arranged in a matched mode, so that the process flow is greatly simplified, and the accuracy and stability of the process are improved.

Description

Technical Field

[0001] This application relates to the field of metal oxide material preparation technology, and in particular to the preparation process and apparatus for tin dioxide. Background Technology

[0002] Tin dioxide (SnO2) is a transparent conductive material with excellent conductivity, gas sensitivity, optical transparency, and chemical stability. It exhibits broad application value and market prospects in numerous fields, including gas sensors, transparent conductive films, solar cells, catalysts, and energy storage electrode materials. With the continued growth in market demand, how to balance product quality with the economic viability of industrial production has become a key issue that urgently needs to be addressed in current tin dioxide preparation processes.

[0003] The main methods for preparing tin dioxide include liquid-phase, gas-phase, and solid-phase methods. Liquid-phase methods require large amounts of acid and alkali reagents, washing, filtration, and other complex steps and processes, resulting in high losses, low yields, and difficult post-processing. Similarly, in solid-phase methods, the tin source is difficult to disperse uniformly, and sintering is prone to occur at high temperatures, which hinders the reduction of high-temperature sintering and simplifies post-processing processes and equipment such as grinding. However, traditional gas-phase methods still generally suffer from problems such as difficulty in quality control, low yields, and complex processes, making it difficult to efficiently prepare tin dioxide. For example, in the spray pyrolysis process, the droplets generated by the spray are prone to agglomeration or adhesion to the inner wall of the equipment, leading to increased raw material losses and decreased quality. Furthermore, current gas-phase processes have low equipment integration and low tin dioxide production efficiency, making it difficult to meet current market and product demands. Summary of the Invention

[0004] Therefore, it is necessary to provide a more efficient tin dioxide production process and apparatus to address the current problems of low production efficiency, unstable quality, complex processes and equipment, and high costs in tin dioxide production.

[0005] In a first aspect, this application provides a process for preparing tin dioxide, comprising the following steps:

[0006] Metallic tin is melted to form the first molten tin;

[0007] An inert gas is introduced into the first molten tin and a preset pressure is controlled to form a second molten tin. The second molten tin is then atomized to form tin mist.

[0008] Furthermore, the second tin mist is subjected to combustion treatment to generate tin dioxide.

[0009] In one embodiment, the preset pressure is 0.2 MPa-0.3 MPa; and / or, the inert gas includes one or more of nitrogen, argon, and helium.

[0010] In one embodiment, during the atomization process, the second molten tin is atomized by compressed gas, and the compressed gas satisfies one or more of the following conditions (1) to (3):

[0011] (1) The gas source of the compressed gas includes air;

[0012] (2) The pressure of the compressed gas is 0.25 MPa-0.4 MPa;

[0013] (3) The compressed gas acts on the second molten tin in the form of a gas with shearing speed, and the gas region is fan-shaped with an included angle of 30°-60°.

[0014] In one embodiment, the temperature during combustion treatment is 900°C-1400°C.

[0015] In one embodiment, the combustion process includes a first combustion process and a second combustion process;

[0016] Optionally, the temperature of the first combustion treatment is 900℃-1200℃;

[0017] Optionally, the temperature of the second combustion treatment is 1200℃-1400℃.

[0018] In one embodiment, the process further includes venting the first molten tin before introducing the inert gas; and / or, the temperatures of the first molten tin and the second molten tin are each independently 400°C-500°C.

[0019] Secondly, this application also provides an apparatus for performing the tin dioxide preparation process provided in the first aspect of the claim, including a feeding device, an atomizing device, and a combustion device; the feeding device includes a material tank, on which an air inlet and an exhaust outlet are provided, the air inlet and the exhaust outlet being independently disposed on the side wall or top of the material tank; the atomizing device includes a hollow tube and an air jet component disposed inside the hollow tube; the combustion device includes a combustion chamber, a burner, a dust removal device, and a smoke exhaust device, the annular burner, the dust removal device, and the smoke exhaust device being independently connected to the top or side wall of the combustion chamber;

[0020] The feeding device is connected to the side wall of the hollow tube through a feeding pipe. The connection between the feeding pipe and the hollow tube is located at the gas outlet end of the jetting component. The second molten tin in the material barrel is transported to the hollow tube through the feeding pipe, and the second molten tin is atomized by the gas ejected by the jetting component.

[0021] The burner is located at the end of the jet component away from the hollow tube.

[0022] In one embodiment, the jetting element includes a connecting pipe and a fan-shaped outlet portion connecting the connecting pipe; and / or, the burner is an annular burner, wherein the annular burner has circumferentially distributed igniters, and the number of igniters is at least two.

[0023] In one embodiment, the opening of the fan-shaped outlet is adjustable, and the opening is 30°-60°; and / or, the connecting pipe is used to introduce compressed gas at the end away from the fan-shaped outlet; and / or, 2-12 igniters are distributed circumferentially on the annular burner; and / or, the igniters ignite the atomized tin mist at the same position.

[0024] In one embodiment, the material conveying pipe is further provided with an insulation layer.

[0025] In one embodiment, the dust removal device includes a dust removal fan and a dust collector, and the air volume of the dust collector is controlled by the dust removal fan, thereby controlling the pressure of the combustion chamber.

[0026] This application provides a method for preparing tin dioxide. First, metallic tin is melted into a first molten tin. An inert gas is then introduced into the first molten tin to create a preset pressure, forming a second molten tin. Under this preset pressure, the second molten tin is transported and atomized to form tin mist. The tin mist is then ignited and burned to prepare tin dioxide. In this method, the preset pressure created by the inert gas not only reduces the oxidizing properties of the molten tin and improves the utilization rate of raw materials, but also provides the power for transporting the molten tin, allowing it to atomize at a specific flow rate. This reduces phenomena such as agglomeration and condensation of the tin mist. Furthermore, under this preset pressure, the atomized tin mist burns at a specific flow rate, effectively controlling the combustion temperature and avoiding incomplete combustion or excessive oxidation. The preparation process provided in this application achieves efficient production of tin dioxide, and the prepared tin dioxide exhibits excellent performance and quality. Attached Figure Description

[0027] Figure 1 A schematic diagram of the overall structure of an apparatus for preparing tin dioxide is shown.

[0028] Figure 2 A schematic diagram of a feeding device for preparing tin dioxide is shown.

[0029] Figure 3 A schematic diagram of an atomizing device for preparing tin dioxide is shown.

[0030] Figure 4 A schematic diagram of a combustion device for preparing tin dioxide is shown.

[0031] Figure 5 A schematic diagram showing the connection relationship between a feeding device, an atomizing device, and a combustion device for preparing tin dioxide is provided.

[0032] Explanation of reference numerals in the attached drawings: 1. Feeding device; 2. Atomizing device; 3. Combustion device; 4. Conveying pipe; 11. Air inlet; 12. Exhaust port; 13. Feeding port; 14. Material bucket; 15. Insulation bucket; 16. Discharge port; 21. Hollow pipe; 22. Jet jet; 221. Fan-shaped outlet; 222. Connecting pipe; 31. Burner; 311. Ignition device; 32. Combustion chamber; 33. Connecting port; 34. Dust removal device; 35. Smoke exhaust device; 36. Burner; 41. Inner conveying pipe; 42. Insulation layer. Detailed Implementation

[0033] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0034] In the description of this application, it should be understood that if terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0035] Furthermore, where the terms "first" and "second" appear, these terms are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, where the term "multiple" appears, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0036] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0037] In this application, unless otherwise expressly specified and limited, the use of descriptions such as "above" or "below" the second feature indicates that the first and second features are in direct contact or indirect contact via an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0038] It should be noted that if an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. If an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. If so, the terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application are for illustrative purposes only and do not represent the only possible implementation.

[0039] The traditional gas-phase method for preparing tin dioxide is difficult to control, resulting in low tin dioxide yield and low raw material utilization. Furthermore, the process is complex, with low integration of supporting equipment, requiring independent control of multiple process stages, which is not economical and fails to meet the current market and product demands.

[0040] Based on this, this application aims to provide a simple and efficient method for producing tin dioxide, achieving the preparation of high-yield, high-performance tin dioxide powder.

[0041] In a first aspect, this application provides a process for preparing tin dioxide, comprising the following steps:

[0042] Metallic tin is melted to form the first molten tin;

[0043] An inert gas is introduced into the first molten tin and a preset pressure is controlled to form a second molten tin. The second molten tin is then atomized to form tin mist.

[0044] Furthermore, the tin mist is subjected to combustion treatment to generate tin dioxide.

[0045] The technical solution of this application mainly involves introducing an inert gas into the first molten tin to form a second molten tin with a preset pressure. Under this preset pressure, the second molten tin is transported and atomized to form tin mist. The tin mist is then further subjected to combustion treatment to prepare tin dioxide. In this process, the effects of controlling the preset pressure with inert gas on the molten tin include: (1) reducing the oxidation degree of the molten tin before atomization and improving the utilization rate of raw materials; (2) ensuring the fluidity and morphology of the molten tin during transportation, ensuring the smooth progress of the atomization process; and (3) the preset pressure formed by the inert gas provides power for the transportation of the molten tin, while simultaneously allowing the molten tin to have a specific flow rate under a specific pressure, thereby enabling the control of the atomization process, combustion process, and tin dioxide morphology. It is understood that a molten tin with a specific flow rate can form a well-shaped tin mist with a specific flow rate during atomization, which is beneficial for controlling the combustion temperature of the tin mist during combustion treatment, thereby ensuring the complete combustion of the tin mist during combustion treatment and obtaining high-yield and high-performance tin dioxide powder. Therefore, the technical solution of this application, which uses inert gas to form a preset pressure, can control the entire tin dioxide preparation process conditions. The process is simple to operate, and the tin dioxide powder obtained has a high yield and excellent performance.

[0046] In one embodiment, the preset pressure is 0.2 MPa-0.3 MPa, including but not limited to 0.2 MPa, 0.22 MPa, 0.24 MPa, 0.26 MPa, 0.28 MPa, 0.3 MPa, or any combination thereof, and values ​​within that range. It can be understood that within this pressure range, the molten solder and solder mist have a specific flow rate to ensure the atomization and combustion effects of the solder mist, especially to control the combustion temperature of the solder mist within an optimal range.

[0047] In one embodiment, the inert gas includes one or more of nitrogen, argon, and helium.

[0048] It is understood that the compressed gas refers to a gas with a certain pressure formed by applying pressure to a gas within a certain space, compressing the gas volume, and increasing the pressure. In one embodiment, the compressed gas includes compressed air. This application uses compressed air to provide power for the atomization of molten tin and to provide oxygen for combustion of the atomized molten tin, which is economical, environmentally friendly, and safe.

[0049] In one embodiment, the pressure of the compressed gas is 0.25 MPa-0.4 MPa, including but not limited to 0.25 MPa, 0.28 MPa, 0.3 MPa, 0.32 MPa, 0.34 MPa, 0.36 MPa, 0.38 MPa, 0.4 MPa, or any combination thereof, and values ​​within that range. The compressed gas provided in this application, within the pressure range, is matched with a second molten tin at a specific flow rate and in a specific form, enabling better atomization of the second molten tin to form a tin mist with better shape and flow rate. This facilitates control of the combustion temperature and combustion completeness during the combustion process, thereby better achieving the technical effects of this application.

[0050] In one embodiment, the compressed gas acting on the second molten tin is in the form of a gas with a shearing velocity, and the gas region is fan-shaped with an included angle of 30°-60°, including but not limited to 30°, 35°, 40°, 45°, 50°, 55°, 60°, or any combination thereof and values ​​within that range. As a non-limiting example, the gas with a shearing velocity includes a gas with a rotational velocity, i.e., the second molten tin is sheared by the rotating gas, causing the second molten tin to form a tin mist.

[0051] It is important to understand that the temperature of the tin mist changes during combustion, which affects the performance and yield of tin dioxide. Based on the temperature changes that occur during tin mist combustion, the flow rate of the second molten tin is controlled, along with the pressure, shape, and shear rate of the compressed gas ejected from the molten tin to atomize it. This synergistic control of the combustion temperature of the tin mist simplifies manual control of the combustion temperature, improves efficiency, and reduces operational errors.

[0052] In one embodiment, the temperature during combustion is 900℃-1400℃, including but not limited to 900℃, 950℃, 1000℃, 1050℃, 1100℃, 1150℃, 1200℃, 1250℃, 1300℃, 1350℃, 1400℃, or any range formed by both of the foregoing and values ​​within that range. Further, the combustion process includes a first combustion process and a second combustion process, wherein the temperature of the first combustion process is 900℃-1200℃, and the temperature of the second combustion process is 1200℃-1400℃. It is understood that the first combustion process is the ignition process of tin mist, and the second combustion process is the process of tin mist continuing to burn after ignition. It should be understood that the temperature refers to the internal temperature of the combustion device, which may be a combustion chamber. It is further important to understand that during the first combustion treatment (ignition), the temperature inside the combustion device is controlled at 900℃-1200℃. After the tin mist is ignited, it continues to undergo a second combustion treatment. If the temperature inside the combustion device is below 900℃ during the first combustion treatment (ignition), the tin mist is difficult to ignite, and the second combustion process is incomplete, resulting in poor tin dioxide powder quality or requiring an increased combustion time, thus reducing production efficiency. If the temperature inside the combustion device is above 1200℃ during the first combustion treatment (ignition), the tin mist can be successfully ignited, but due to the excessively high temperature inside the combustion chamber, the tin mist will continue to heat up during the second combustion treatment, leading to excessive oxidation of the tin dioxide powder and a decline in quality. Therefore, this application can ensure the combustion of tin mist by controlling the temperature during the combustion treatment, thereby obtaining tin dioxide powder with excellent performance and high yield.

[0053] As a non-limiting example, an appropriate amount of combustion-supporting gas, such as oxygen, can be introduced during the ignition process to further improve ignition efficiency and combustion completeness.

[0054] In one embodiment, the pressures during the first and second combustion processes are each independently controlled to negative pressure. It is understood that the pressure refers to the internal pressure of the combustion device. For example, when tin mist burns in the combustion chamber, the internal pressure of the combustion chamber is controlled to be negative. Controlling the pressure (inside the combustion device) to negative pressure during ignition and combustion provides a more favorable environment for tin mist combustion and also ensures that the flue gas generated during combustion is discharged in a timely manner.

[0055] In one embodiment, the process includes purging the first molten tin before introducing the inert gas. Purging refers to removing air from the container holding the molten tin. This purging process removes air from the container (tank) before introducing the inert gas, specifically oxidizing gases such as oxygen, reducing oxidation of the molten tin and facilitating the smooth operation of the entire production process. For example, if the container is not purged, the molten tin will oxidize excessively, forming a layer of tin oxide on the surface. Excessive oxide buildup can clog conveying devices (such as feed pipes and jetting components), hindering the smooth transport and atomization of the molten tin and impacting the process.

[0056] In one embodiment, the purging process includes: purging the container containing the first molten tin with an inert gas for displacement. As a non-limiting example, the inert gas includes one or more of nitrogen, argon, and helium.

[0057] In one embodiment, the temperatures of the first molten tin and the second molten tin are each independently between 400°C and 500°C, including but not limited to 400°C, 420°C, 440°C, 460°C, 480°C, 500°C, or any combination thereof and values ​​within that range.

[0058] The tin dioxide preparation process provided in this application is simple to operate. High-quality tin dioxide powder can be efficiently produced by controlling the specific preset pressure of the inert gas on the molten tin. Furthermore, the combustion process of tin dioxide can be controlled by adjusting the pressure and / or morphology of the compressed gas during atomization. The preparation process provided in this application reduces manual operation and has significant economic advantages.

[0059] Secondly, this application also provides an apparatus for performing the tin dioxide preparation process provided in the first aspect of the claim, comprising a feeding device 1, an atomizing device 2, and a combustion device 3; the feeding device 1 includes a material tank 14, on which an air inlet 11 and an exhaust outlet 12 are provided, the air inlet 11 and the exhaust outlet 12 being independently disposed on the side wall or top of the material tank 14; the atomizing device 2 includes a hollow tube 21 and an air jet 22 disposed inside the hollow tube 21; the combustion device 3 includes a combustion chamber 32, a burner 31, a dust removal device 34, and a smoke exhaust device 35, the annular burner 31, the dust removal device 34, and the smoke exhaust device 35 being independently connected to the top or side wall of the combustion chamber 32;

[0060] The feeding device 1 is connected to the side wall of the hollow tube 21 through the feeding pipe 4. The connection between the feeding pipe 4 and the hollow tube 21 is located at the gas outlet end of the jetting element 22. The second molten tin in the material barrel 14 is transported to the hollow tube 21 through the feeding pipe 4, and the second molten tin is atomized by the gas sprayed out by the jetting element 22.

[0061] The burner 31 is located at the end of the jet 22 that is away from the hollow tube 21.

[0062] It is understood that the gas is formed by compressed gas being ejected through the jet 22.

[0063] In one embodiment, the jetting element 22 includes a connecting pipe 222 and a fan-shaped outlet portion 221 communicating with the connecting pipe 222. As a non-limiting example, the fan-shaped outlet portion 221 is made of stainless steel, not limited to 304 or 316 stainless steel.

[0064] In one embodiment, the burner 31 is an annular burner 31, wherein the annular burner 31 has circumferentially distributed igniters 311, and the number of igniters 311 is at least two.

[0065] In one embodiment, the opening of the fan-shaped outlet 221 is adjustable, and the opening is 30°-60°, including but not limited to 30°, 35°, 40°, 45°, 50°, 55°, 60° or any combination thereof and values ​​within that range.

[0066] In one embodiment, the connecting pipe 222 is used to introduce compressed gas at the end away from the fan-shaped outlet 221.

[0067] In one embodiment, the annular burner 31 has 2-12 igniters 311 distributed circumferentially. The number of igniters 311 includes, but is not limited to, 2, 4, 6, 8, 10, 12, or any combination thereof and values ​​within that range. As a non-limiting example, the igniters 311 may be uniformly or non-uniformly distributed circumferentially in the annular burner 31.

[0068] In one embodiment, the igniter 311 ignites the tin mist at the same location, which improves the ignition efficiency of the tin mist, ensures continuous combustion, and avoids ineffective ignition or incomplete combustion of some tin mist due to fluctuations in the ignition location. This also ensures uniform temperature in the combustion zone and reduces problems such as product agglomeration due to localized overheating or low product crystallinity due to localized insufficient temperature. It should be understood that "the same location" refers to the interior of the combustion chamber 32, specifically meaning that multiple igniters ignite the tin mist with their flames converging at the same point.

[0069] In one embodiment, the outside of the conveying pipe 4 is further provided with a heat insulation layer 42. The heat insulation layer 42 is used to keep the second molten tin in the conveying pipe 4 warm, ensuring the fluidity of the second molten tin and smooth conveying and atomization. As a non-limiting example, the heat insulation layer 42 is implemented by one or more of an electric heating device, a hot fluid, and a heat insulation material. The electric heating device includes a heating wire, the hot fluid includes hot air, hot steam, and hot solvents, etc., and the heat insulation material includes polyurethane foam, rock wool, glass wool, and aluminum silicate, etc., or a vacuum insulation layer 42.

[0070] In one embodiment, the dust removal device 34 includes a dust removal fan and a dust collector, and the air volume of the dust collector is controlled by the dust removal fan, thereby controlling the pressure of the combustion chamber 32.

[0071] As a non-limiting example, the dust collector includes a cyclone dust collector or a bag dust collector.

[0072] To better illustrate the tin dioxide preparation process and the apparatus for performing the process described in this application, the following specific embodiments are provided in conjunction with the accompanying drawings.

[0073] See Figure 1 , Figure 1 A schematic diagram of an apparatus for performing a tin dioxide preparation process according to an embodiment of this application is shown. The apparatus provided in one embodiment of this application includes a feeding device 1, an atomizing device 2, and a combustion device 3. The feeding device 1 and the atomizing device 2 are connected by a conveying pipe 4. The atomizing device 2 is adjacent to the combustion device 3. The atomizing device 2 atomizes the molten tin and outputs tin mist. The tin mist is conveyed to the interior of the combustion chamber 32 through a connecting port 33. The tin mist is ignited at the same position inside the combustion chamber 32 by the burner 31 and continues to burn.

[0074] Understandably, see Figure 1 As shown, the feeding device 1, the atomizing device 2, and the combustion device 3 can each be independently adjusted in position according to industrial production conditions.

[0075] See Figure 2 , Figure 2 This diagram illustrates a feeding device 1 of an apparatus for performing a tin dioxide preparation process according to an embodiment of this application. The feeding device 1 provided in this embodiment includes a material tank 14, which has an air inlet 11, an exhaust outlet 12, and a feeding inlet 13. An insulation tank 15 is located outside the material tank 14. The air inlet 11, exhaust outlet 12, and feeding inlet 13 are each independently located on the top of the material tank 14. The air inlet 11 has an air inlet valve to control the flow of gas. The exhaust outlet 12 has an exhaust valve to control the discharge of gas from inside the material tank 14. Tin liquid is added through the feeding inlet 13. The insulation tank 15, located on the outer layer of the material tank 14, can keep the tin liquid inside the material tank 14 warm, reducing solidification and ensuring the fluidity of the tin liquid.

[0076] See Figure 3 , Figure 3 A schematic diagram of an atomizing device 2 for performing an atomization process in the preparation of tin dioxide is shown. An embodiment of the atomizing device 2 provided in this application includes a hollow tube 21 and an atomizing element 22. The atomizing element 22 includes a fan-shaped outlet 221 and a connecting pipe 222 communicating with the fan-shaped outlet 221. The connecting pipe 222 is connected to the gas input end of the fan-shaped outlet 221 and is used to receive compressed gas input through the connecting pipe 222. The fan-shaped outlet 221 is located inside one end of the hollow tube 21 to ensure that all gas ejected from the fan-shaped outlet 221 falls into the hollow tube 21. The connecting pipe 222 is located outside the hollow tube 21 and is used to introduce compressed gas, transporting the introduced compressed gas to the fan-shaped outlet 221 and outputting it through the fan-shaped outlet 221, forming a fan-shaped gas region. The included angle of the fan-shaped region is 30°-60°, and the included angle is controlled by the shape of the fan-shaped outlet 221.

[0077] The structure connecting the feeding device 1 and the atomizing device 2 is a conveying pipe 4. One end of the conveying pipe 4 is connected to the outlet 16 at the bottom of the feeding tank 14, and the other end is connected to the side wall of the hollow tube 21 in the atomizing device 2. Thus, the second molten tin in the feeding tank 14 is conveyed to the hollow tube 21 for atomization through the conveying pipe 4. The connection between the conveying pipe 4 and the hollow tube 21 is located on one side of the fan-shaped outlet 221 of the jetting element 22 and is adjacent to the fan-shaped outlet 221 of the jetting element 22. This ensures that the second molten tin is conveyed to the front of the fan-shaped outlet 221 of the jetting element 22 and atomized by the gas ejected from the fan-shaped outlet 221 of the jetting element 22 to form tin mist.

[0078] As a non-limiting example, a valve may be provided on the feed pipe 4 to control the amount and flow rate of the second molten tin.

[0079] Figure 3 The connection between the annular burner 31 and the atomizing device 2 is also shown. The annular burner 31 is located at the end of the jet 22 away from the hollow tube 21 to ensure that the tin mist ejected from the hollow tube 21 is ignited. The annular burner 31 has 12 igniters 311 distributed circumferentially. These igniters 311 ignite the tin mist ejected from the hollow tube 21, and the ignition points are located on the horizontal axis of the annular center of the annular burner 31, at the same location inside the combustion chamber 32.

[0080] See Figure 4 , Figure 4 A schematic diagram of a combustion device 3 for performing a tin dioxide preparation process according to an embodiment of this application is shown. The combustion device 3 provided in an embodiment of this application includes a combustion chamber 32, a burner 31, a dust removal device 34, and a smoke exhaust device 35. The top of the combustion chamber 32 is provided with a dust removal port communicating with the dust removal device 34, and a smoke exhaust port communicating with the smoke exhaust device 35.

[0081] The combustion chamber 32 has a connecting port 33 on its side wall for the introduction of tin mist. The tin mist generated in the atomizing device 2 enters the interior of the combustion chamber 32 through the connecting port 33 and is ignited inside the combustion chamber 32 by the annular burner 31. It can be understood that the annular burner 31 is located outside the combustion chamber 32, and the spatial position of the annular burner 31 igniting the tin mist is located inside the combustion chamber 32.

[0082] The dust removal device 34 includes a dust removal fan and a dust collector, which may be a cyclone dust collector or a bag filter dust collector. The dust collector is connected to a dust collection pipe. Tin mist is burned inside the combustion chamber 32, and the resulting tin dioxide is collected by the dust collector. During the tin dioxide collection process, the suction volume and pressure of the dust collector are controlled by the dust removal fan to achieve the collection of tin dioxide and simultaneously control the pressure of the combustion chamber 32.

[0083] Combination Figure 1 and Figure 5 The apparatus shown in this application provides a preferred embodiment 1 of tin dioxide, the preparation process of which specifically includes:

[0084] Close the dust removal port in the combustion device 3, and at the same time open the exhaust port to heat the temperature of the combustion chamber 32 to 1200℃, and then start the burner 31.

[0085] The tin ingot is melted in a tin melting furnace and heated to 550°C. After removing the slag from the surface of the molten tin, the first molten tin is added to the tank 14 through the feeding port 13. The first molten tin is kept warm in the heat preservation tank 15, and the temperature of the first molten tin in the tank 14 is maintained at 500°C.

[0086] Open the exhaust valve on the exhaust port 12 at the top of the feeding device 1, and simultaneously open the air inlet valve on the air inlet 11 at the top of the feeding device 1 to introduce nitrogen into the air inlet 11. At this time, the air inside the material barrel 14 is discharged through the exhaust port 12 and replaced by nitrogen. After the replacement is complete, close the exhaust valve and continue to introduce nitrogen into the material barrel 14 until the internal pressure of the material barrel 14 is 0.25 MPa, forming the second molten tin. At this time, open the valve on the conveying pipe 4, and the second molten tin is transported to the atomizing device 2 through the conveying pipe 4 for atomization. During this process, nitrogen is continuously introduced to ensure that the internal pressure of the material barrel 14 is maintained at 0.25 MPa.

[0087] During the process of the second molten tin being transported to the atomizing device 2 through the conveying pipe 4, the heating wire in the insulation layer 42 wrapped around the outside of the conveying pipe 4 is activated to ensure the fluidity of the second molten tin in the conveying pipe 4 and to prevent the second molten tin from solidifying and clogging the conveying pipe 4 due to a drop in temperature. When the second molten tin is transported to the hollow tube 21 of the atomizing device 2 through the conveying pipe 4, 0.3MPa compressed gas is introduced through the connecting pipe 222 and sprayed out from the fan-shaped outlet 221 of the jet nozzle 22 with a fan-shaped angle of 45°, forming a fan-shaped gas with a certain rotation speed at a 45° angle. This gas shears the second molten tin in front of the fan-shaped outlet 221 of the jet nozzle 22, thus atomizing the second molten tin and forming a tin mist with a specific flow rate. The tin mist is sprayed out from the outlet of the hollow tube 21 and ignited at the same position in the combustion chamber 32 by an annular burner 31 with 12 igniters 311 evenly distributed around the circumference, and continues to burn in the combustion chamber 32.

[0088] During the ignition of the tin mist, the temperature inside the combustion chamber 32 is 1200℃. After the tin mist is completely ignited, heating of the combustion chamber 32 is stopped, and the dust removal fan is started and the suction volume is adjusted to a low level to maintain the internal air pressure of the combustion chamber 32 as a negative pressure. The exhaust port is closed, and as the tin mist continues to burn in the combustion chamber 32, the temperature inside the combustion chamber 32 is maintained in the range of 1200℃-1400℃. The suction volume of the dust removal fan is increased, and the tin dioxide powder formed by combustion is collected by the bag filter in the dust removal device 34.

[0089] When the apparatus of this application is used to perform the above-mentioned tin dioxide preparation process, the whiteness of the obtained tin dioxide powder is ≥85%, and the input-output mass ratio is 1:1.2.

[0090] In this example, tin dioxide powder can be further prepared through continuous feeding. The continuous feeding process is as follows: after all the tin in the feed tank 14 has been fed, the air inlet valve in the feeding device 1 is closed, and the exhaust valve is opened simultaneously. A second tank of molten tin is then added through the feeding port 13. The aforementioned process is then repeated, including venting and nitrogen introduction, thereby achieving continuous production of tin dioxide. The preparation process executed by the device can achieve a tin molten material feeding rate of 50 kg / h while ensuring that the whiteness of the tin dioxide powder is ≥85%.

[0091] This application also provides another preferred example 2 of tin dioxide, which differs from example 1 in that nitrogen gas is continuously introduced to maintain the internal pressure of the material container 14 at 0.2 MPa, and the pressure of compressed air is 0.25 MPa; all other aspects are the same as in example 1. The tin dioxide powder prepared in this example 2 has a whiteness of ≥85%.

[0092] This application also provides another preferred example 3 of tin dioxide, which differs from example 1 in that nitrogen gas is continuously introduced to maintain the internal pressure of the material container 14 at 0.3 MPa, and the pressure of compressed air is 0.4 MPa; all other aspects are the same as in example 1. The tin dioxide powder prepared in this example 3 has a whiteness of ≥85%.

[0093] This application also provides another preferred example 4 of tin dioxide, which differs from Example 1 above in that: during the ignition of the tin mist, the temperature inside the combustion chamber 32 is 900°C, and the temperature inside the combustion chamber 32 is within the range of 1200°C-1400°C; all other aspects are the same as in Example 1. The tin dioxide powder prepared in Example 4 has a whiteness of ≥80%.

[0094] This application also provides another example 5 of tin dioxide, which differs from example 1 in that nitrogen gas is continuously introduced to maintain the internal pressure of the material container 14 at 0.15 MPa, and the pressure of compressed air is 0.3 MPa; all other aspects are the same as in example 1. The tin dioxide powder prepared in this example 5 has a whiteness of ≥75%.

[0095] This application also provides another example 6 of tin dioxide, which differs from Example 1 above in that nitrogen gas is continuously introduced to maintain the internal pressure of the material container 14 at 0.25 MPa, and the pressure of compressed air is 0.2 MPa; all other aspects are the same as in Example 1. The tin dioxide powder prepared in this Example 6 has a whiteness of ≥75%.

[0096] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0097] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A process for preparing tin dioxide, characterized in that, Includes the following steps: Metallic tin is melted to form the first molten tin; An inert gas is introduced into the first molten tin and a preset pressure is controlled to form a second molten tin. The second molten tin is then atomized to form tin mist. Furthermore, the tin mist is subjected to combustion treatment to generate tin dioxide.

2. The tin dioxide preparation process according to claim 1, characterized in that, The preset pressure is 0.2MPa-0.3MPa; and / or the inert gas includes one or more of nitrogen, argon and helium.

3. The tin dioxide preparation process according to claim 1, characterized in that, During the atomization process, the second molten tin is atomized by compressed gas, and the compressed gas satisfies one or more of the following conditions (1) to (3): (1) The gas source of the compressed gas includes air; (2) The pressure of the compressed gas is 0.25 MPa-0.4 MPa; (3) The compressed gas acts on the second molten tin in the form of a gas with shearing speed, and the gas region is fan-shaped with an included angle of 30°-60°.

4. The tin dioxide preparation process according to claim 1, characterized in that, The temperature during combustion treatment is 900℃-1400℃.

5. The tin dioxide preparation process according to claim 4, characterized in that, The combustion treatment process includes a first combustion treatment and a second combustion treatment; Optionally, the temperature of the first combustion treatment is 900℃-1200℃; Optionally, the temperature of the second combustion treatment is 1200℃-1400℃.

6. The process for preparing tin dioxide according to any one of claims 1 to 5, characterized in that, The process includes venting the first molten tin before introducing the inert gas; and / or, the temperatures of the first molten tin and the second molten tin are each independently 400°C-500°C.

7. An apparatus for performing the tin dioxide preparation process according to any one of claims 1 to 6, characterized in that, The device includes a feeding device, an atomizing device, and a combustion device. The feeding device includes a material tank with an air inlet and an exhaust outlet, each independently located on the side wall or top of the material tank. The atomizing device includes a hollow tube and an air jet component disposed inside the hollow tube. The combustion device includes a burner, a combustion chamber, a dust removal device, and a smoke exhaust device, each independently connected to the top or side wall of the combustion chamber. The feeding device is connected to the side wall of the hollow tube through a feeding pipe. The connection between the feeding pipe and the hollow tube is located at the gas outlet end of the jetting component. The second molten tin in the material barrel is transported to the hollow tube through the feeding pipe, and the second molten tin is atomized by the gas ejected by the jetting component. The burner is located at the end of the jet component away from the hollow tube.

8. The apparatus according to claim 7, characterized in that, The jetting component includes a connecting pipe and a fan-shaped outlet portion connecting the connecting pipe; and / or, the burner is an annular burner, wherein the annular burner has circumferentially distributed igniters, and the number of igniters is at least two.

9. The apparatus according to claim 8, characterized in that, The opening of the fan-shaped outlet is adjustable, and the opening is 30°-60°; and / or, the connecting pipe is used to introduce compressed gas at the end away from the fan-shaped outlet; and / or, 2-12 igniters are distributed circumferentially on the annular burner; and / or, the igniters ignite the atomized tin mist at the same position.

10. The apparatus according to any one of claims 7 to 9, characterized in that, The material conveying pipe is also provided with an insulation layer; and / or, the dust removal device includes a dust removal fan and a dust collector, wherein the dust removal fan can control the air volume of the dust collector, thereby controlling the pressure of the combustion chamber.

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