Preparation method and preparation device of nano indium oxide powder

Abstract

The invention discloses a preparation method and a preparation device of nano indium oxide powder, and belongs to the technical field of nano material preparation. The method comprises the following steps: melting an indium block under a vacuum condition, and then atomizing into indium liquid mist; and introducing carrier gas to blow the indium liquid mist into the quartz rotating tube for microwave heating, then rotating the quartz rotating tube, introducing oxygen to react with the indium liquid mist, and after the reaction is completed, cooling to obtain indium oxide powder. By controlling the oxygen concentration and the indium liquid mist flow rate in the reaction chamber and accurately regulating and controlling parameters such as the rotation speed of the quartz tube, the microwave reaction temperature and the gas flow, regulation and control on the morphology and purity of indium oxide are realized, and the obtained indium oxide has the advantages of high purity, high crystallinity, specific morphology and controllable grain size; the method can be widely applied to the fields of electronics, optics, new energy and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of nano material preparation, and in particular relates to a preparation method and a preparation device of nano indium oxide powder. Background Art

[0002] Indium oxide, an important wide-bandgap semiconductor material, has key applications in transparent conductive films, gas sensors, and other fields. Traditional preparation methods, such as the sol-gel method, suffer from lengthy processes and residual solvents, while vapor deposition methods face challenges such as complex equipment and low production efficiency. While existing combustion methods offer high efficiency, they face technical bottlenecks such as uneven product particle size and poor morphology controllability. Rapid preparation and precise control of indium oxide nanopowders through process innovation have become pressing challenges in this field. Summary of the Invention

[0003] In order to solve or partially solve the problems existing in the related art, the present invention provides a method and a device for preparing nano-indium oxide powder.

[0004] The present invention provides a method for preparing nano-indium oxide powder, comprising the following steps:

[0005] (1) Melting the indium block under vacuum conditions and then atomizing it into indium liquid mist;

[0006] (2) A carrier gas is introduced to blow the indium liquid mist into a quartz rotating tube for microwave heating, and then the quartz rotating tube is rotated and oxygen is introduced to react with the indium liquid mist. After the reaction is completed, indium oxide powder is obtained by cooling.

[0007] Preferably, in step (1), the indium block is heated and melted by a high-frequency induction coil, the melting temperature is 180-250° C., the heating rate is 5-10° C. / min, and the vacuum degree of the vacuum condition is 30-300 Pa.

[0008] Preferably, in step (1), ultrasonic atomization is used, the ultrasonic vibration frequency is 30kHz-180kHz, and the atomization pressure is 0.1-0.5MPa. The present invention controls the particle size of the droplets after atomization of the indium liquid by adjusting parameters such as the frequency of the ultrasonic wave, which helps to obtain indium liquid mist of suitable particle size to meet the conditions for subsequent sufficient reaction with oxygen in the quartz rotating tube, thereby ensuring the quality of the indium oxide powder, such as uniform particle size and no obvious agglomeration.

[0009] Preferably, the carrier gas is argon, and the flow rate of the carrier gas is 0.5-50 L / min.

[0010] Preferably, the rotation speed of the quartz rotating tube is 10-30 rpm.

[0011] Preferably, in step (2), the flow rate of the indium liquid mist is 0.05-0.5 L / min, the flow rate of the oxygen is 1-100 L / min, and the purity of the oxygen is 99.99%.

[0012] Preferably, the power of the microwave heating is 800-1500W, the heating rate is 100-150°C / min, and the temperature of the microwave heating is 900-1100°C.

[0013] In a high-temperature microwave field, microwaves (typically at a frequency of 2.45 GHz) act on polar molecules (such as hydroxyl groups and water molecules in the InO precursor), causing them to rotate at high frequencies (approximately 2.45 billion times per second). This intense friction between the molecules generates heat and prevents them from agglomerating. The rapid and uniform heating characteristics of microwaves (5 to 10 times faster than conventional heating rates) maintain a highly active reaction interface, avoiding the "temperature gradient" problem of conventional heating, reaction stagnation caused by localized uneven heating, or side reactions (such as impurity formation or incomplete oxidation) caused by localized overheating. This improves the purity and crystalline quality of indium oxide. The microwave energy is directly absorbed by the reactants, minimizing heat loss and achieving energy efficiency 2 to 3 times that of conventional methods. Microwave equipment can precisely control the reaction temperature and progress by adjusting parameters such as power and time, facilitating automated operation and process optimization, making it suitable for large-scale production or rapid laboratory screening.

[0014] The present invention also claims protection for a preparation device for the nano-indium oxide powder, which includes: an evaporation furnace, an oxygen tank, a carrier gas tank, an ultrasonic atomization tube, a quartz rotary tube, a water cooling system, a microwave heating system, a vacuum pump, and a recovery device.

[0015] The evaporation furnace and the carrier gas tank are connected to the ultrasonic atomization tube through a pipeline. The ultrasonic atomization tube and the oxygen tank are combined and then connected to the quartz rotating tube. The vacuum pump is connected to the pipeline.

[0016] A microwave system is mounted on the outer wall of the rotating quartz tube, which is connected to a water cooling system, which is then connected to a recovery device. The microwave device is installed on the upper and lower sides of the rotating quartz tube, or on all four sides of the tube in a rectangular box-like structure, or around the outer wall of the tube, heating the reactants inside the tube.

[0017] The present invention uses a nano-indium oxide powder preparation device to prepare nano-indium oxide powder: indium metal can be heated and melted under vacuum conditions, and the melting point of indium metal is 156.61° C. Therefore, the heating temperature should be set above the melting point of indium metal to melt the indium metal. The carrier gas in the gas cylinder is opened, and the pressure generated by the carrier gas causes the indium liquid to be pressed into the ultrasonic atomization system to become indium vapor. Since the heating rate of the microwave system is much higher than that of the crucible and the coil, it will quickly reach the high temperature required for the reaction. Oxygen is then introduced to blow the indium vapor into the rotating tube. At the same time, the quartz rotating tube begins to rotate, and the centrifugal force generated can prevent the reaction products from agglomerating. Therefore, the indium vapor undergoes an oxidation reaction in the quartz rotating tube. The microwave system provides a high-energy activation environment, causing the particles to collide with the wall of the quartz rotating tube, making it more difficult to agglomerate while doubling the particle nucleation rate. The average particle size of the indium oxide powder is reduced to 35±5nm. The generated indium oxide product is blown into a water-cooling system with a perforated sieve tube, quickly pulverized under the initial cooling of cooling water, and then falls into an air-cooling system through the perforated sieve tube for further cooling to obtain low-temperature indium oxide powder. The powder is then further refined by an ultrafine grinder and finally falls into a collection box.

[0018] Preferably, the evaporation furnace is an induction coil heating crucible, and the heating unit in the induction heating evaporation furnace adopts a high-frequency induction coil.

[0019] Preferably, the diameter of the atomization pipe of the ultrasonic atomization tube is 1 to 1.5 cm.

[0020] Preferably, the inner diameter of the quartz rotating tube is 80 mm, the outer wall of the quartz rotating tube is coated with a silicon nitride coating, the quartz rotating tube is connected to a motor, and the power of the motor is 400-2000W.

[0021] Preferably, a valve is provided between the water cooling system and the quartz rotating tube, and the water cooling system comprises a water cooling tube, a water cooling box and a perforated sieve tube. The inner diameter of the perforated sieve tube is 60 mm, and the pore size is 10 to 50 μm. The holes of the perforated sieve tube are arranged at the bottom, which is conducive to the preliminary screening of the particle size. The water cooling tube surrounds the outer wall of the perforated sieve tube and absorbs the heat generated by the reaction through circulating cooling water. The inlet and outlet of the water cooling tube are connected to the water cooling box (the water cooling box has a built-in cooling medium, such as cooling water), forming a closed loop to achieve heat exchange. The perforated sieve tube is wrapped by the water cooling tube, exposing the sieve holes at the bottom of the perforated sieve tube. The circulating cooling water of the water cooling tube absorbs heat and cools the product in the perforated sieve tube. At the same time, the sieve holes are used to achieve preliminary screening of the particle size to ensure that the particle size of the powder entering the recovery device meets the requirements. One end of the perforated sieve tube is connected to the quartz rotating tube for receiving the indium oxide product generated by the reaction; the other end is connected to the recovery device so that the powder after cooling and screening enters the subsequent recovery process.

[0022] Preferably, the recovery device is a box-type chamber, and there is an air-cooling pipe in the chamber connecting the cyclone separator and the bag dust collector, which is called an air-cooled bag recovery device. The ultrafine grinder is under the air-cooled bag recovery device. The indium oxide powder after air cooling will be distributed in the bag and then crushed by the ultrafine grinder and collected. Then, all the indium oxide powder can be obtained by taking out the entire box-type chamber.

[0023] The technical solution provided by the present invention has the following beneficial effects: By controlling the oxygen concentration and indium liquid mist flow rate in the reaction chamber and precisely regulating parameters such as the quartz tube rotation speed, microwave reaction temperature, and gas flow rate, the present invention achieves regulation of the morphology and purity of indium oxide. The resulting indium oxide has the advantages of high purity, high crystallinity, specific morphology, and controllable grain size, and can be widely used in electronics, optics, and new energy fields. Compared with traditional processes, the present invention's method for preparing nanopowders through indium oxide vapor microwave-assisted rotary oxidation and dedicated cooling and pulverization equipment has the advantages of fast preparation speed and uniform powder particle size. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic structural diagram of the device for preparing nano-indium oxide powder according to the present invention.

[0025] Figure 2 This is a scanning electron microscope photograph of the high-purity nano-indium oxide powder prepared in Example 2.

[0026] Figure 3 This is a scanning electron microscope photograph of the high-purity nano-indium oxide powder prepared in Example 3.

[0027] Figure 4 This is a scanning electron microscope photograph of the high-purity nano-indium oxide powder prepared in Example 4.

[0028] Figure 5 This is a scanning electron microscope photograph of the high-purity nano-indium oxide powder prepared in Comparative Example 1.

[0029] In the figure, 1. evaporation furnace, 2. vacuum pump, 3. valve I, 4. carrier gas tank, 5. ultrasonic atomization tube, 6. valve II, 7. oxygen tank, 8. motor, 9. quartz rotary tube, 10. microwave heating system, 11. valve III, 12. water cooling system, 13. water cooling box, 14. perforated sieve tube, 15 recovery device. DETAILED DESCRIPTION

[0030] Example 1

[0031] A nano-indium oxide powder preparation device comprises: an evaporation furnace 1, an oxygen tank 7, a carrier gas tank 4, an ultrasonic atomization tube 5, a quartz rotary tube 9, a water cooling system 12, a microwave heating system 10, a vacuum pump 2 and a recovery device 15.

[0032] The evaporator 1 is an induction-heated evaporator with a built-in crucible. The heating unit within the induction-heated evaporator utilizes a high-frequency induction coil. The evaporator 1 and carrier gas tank 4 are connected to an ultrasonic atomizer tube 5 via a pipeline. The atomizer tube and oxygen tank 7 are connected to a quartz rotary tube 9 via a pipeline. The atomizer tube has a diameter of 1-1.5 cm. Valves I and II are installed on the carrier gas tank 4 and oxygen tank 7, respectively. The carrier gas is argon, and the purity of the oxygen is above 99.99%.

[0033] The inner diameter of the quartz rotating tube 9 is 80 mm, the outer wall of the quartz rotating tube 9 is coated with a silicon nitride coating, which is heat-resistant to 1200°C. The quartz rotating tube 9 is connected to a motor 8, which controls the rotation speed of the quartz rotating tube 9. The power of the motor 8 is 400-2000W.

[0034] A microwave system is installed on the outer wall of the quartz rotating tube 9 ; the quartz rotating tube 9 is connected to a water cooling system 12 ; and the water cooling system 12 is connected to a recovery device 14 .

[0035] The microwave heating system 10 is a microwave device, which is installed on the upper and lower sides of the quartz rotating tube 9, or the upper, lower, left and right sides of the quartz rotating tube 9 are rectangular box-shaped structures, or installed around the outer wall of the quartz rotating tube 9 to heat the reactants inside the quartz rotating tube 9.

[0036] Valve III is installed between the water-cooling system 12 and the quartz rotating tube 9. The water-cooling system 12 includes a water-cooling tube, a water-cooling box 13, and a perforated sieve tube 14. The perforated sieve tube 14 has an inner diameter of 60 mm and a pore size of 10 to 50 μm. The water-cooling tube surrounds the outer wall of the perforated sieve tube 14 and absorbs the heat generated by the reaction through circulating cooling water. The inlet and outlet of the water-cooling tube are connected to the water-cooling box 13 (which contains a built-in cooling medium, such as cooling water), forming a closed loop to achieve heat exchange. The perforated sieve tube 14 is located below and surrounded by the water-cooling tube. The circulating cooling water in the water-cooling tube absorbs heat, cooling the product within the perforated sieve tube 14. At the same time, the sieve holes are used to perform preliminary particle size screening to ensure that the powder entering the recovery device meets the particle size requirements. One end of the perforated sieve tube 14 is connected to the quartz rotating tube 9 to receive the indium oxide product generated by the reaction; the other end is connected to the recovery device, allowing the cooled and screened powder to enter the subsequent recovery process.

[0037] The recovery device 14 is a box-type chamber with an air-cooling pipe connecting the cyclone separator and the bag dust collector, which is called an air-cooled bag recovery device. The ultrafine grinder is under the air-cooled bag recovery device. The indium oxide powder after air cooling will be distributed in the bag and then crushed by the ultrafine grinder and collected. Then, you only need to take out the entire box-type chamber to obtain all the indium oxide powder.

[0038] The vacuum pump 2 is connected to the pipeline and is used to adjust the vacuum degree of the entire reaction.

[0039] Example 2

[0040] The nano-indium oxide powder preparation device described in Example 1 is used to prepare nano-indium oxide powder, comprising the following steps:

[0041] (1) Open the hatch of the evaporation furnace, place the solid elemental indium in the crucible in the evaporation furnace, and place the built-in crucible on the high-frequency heating coil. Close the hatch of the evaporation furnace, turn on the vacuum pump to evacuate the vacuum, and wait until the vacuum meter shows that the required vacuum degree reaches 30 Pa.

[0042] (2) Then, turn on the power switch of the high-frequency induction coil and start heating. The high-frequency induction coil heats up at a rate of 5°C / min. During the melting process of the indium block, argon gas is introduced for protection at a flow rate of 5 L / min, and the vacuum degree in the system is maintained at 100-200 Pa. After reaching the heating temperature of 180°C, which is the melting temperature of solid elemental indium, the indium block is completely melted to obtain indium liquid.

[0043] (3) Then turn on ultrasonic atomization, the ultrasonic frequency of ultrasonic atomization is 180kHz, the atomization pressure is 0.5MPa, the injection rate of argon is set to 20L / min, and the vacuum degree during the atomization and oxidation reaction is maintained at 200pa. The indium liquid in the crucible flows into the ultrasonic atomization tube through the pipeline and is atomized and then blown into the quartz rotating tube. After the indium liquid mist enters the quartz rotating tube completely, the carrier gas is turned off. At this time, the microwave heating system starts to heat the quartz rotating tube. The heating rate is 150℃ / min. The heating temperature reaches and is maintained at 1100℃. Then the motor is started and the quartz rotating tube starts to rotate at a speed of 30rpm. At this time, the oxygen valve is opened to introduce oxygen. The oxygen injection rate is 40L / min. The remaining indium mist is blown into the quartz rotating tube so that the oxygen and the indium mist react.

[0044] (4) Observe the situation inside the quartz rotating tube until there is no indium mist in the pipe connected to the rear end of the atomizing tube (when there is basically no indium liquid mist in the pipe) and a large amount of product is deposited on the inner wall of the quartz rotating tube, turn off the microwave heating system and stop heating. Open valve III between the quartz rotating tube and the water cooling system, stop the quartz rotating tube, increase the oxygen flow rate to 60L / min, and blow the reaction product into the perforated sieve tube; wait for the indium oxide product to enter the perforated sieve tube with an inner diameter of 60mm and an aperture of 50μm, and then fall into the bag through the aperture of the perforated sieve tube under the cooling of the 25℃ water cooling system. After cooling and adsorption by the air cooling system again, it enters the ultrafine grinder for particle size refinement and then falls into the collection box. Open the oxygen valve to allow O2 to enter the quartz rotating tube and the perforated sieve tube. After the vacuum gauge returns to atmospheric pressure, collect the indium oxide powder deposited in the collection box in the reaction chamber to obtain high-purity nano-indium oxide powder.

[0045] The purity of high-purity nano-indium oxide powder is 99.999%. Figure 2 A scanning electron microscope image of the prepared high-purity nano-indium oxide powder shows a uniform particle size of approximately 20 nm with no apparent agglomeration. The particle size D50 is 145 nm. The specific surface area is 11.85 m2 / g.

[0046] Example 3

[0047] The nano-indium oxide powder preparation device described in Example 1 is used to prepare nano-indium oxide powder, comprising the following steps:

[0048] (1) Open the evaporation furnace door, place the solid elemental indium in the evaporation furnace, and place the built-in crucible on the high-frequency heating coil. Close the box door, turn on the vacuum pump to evacuate the vacuum, and wait until the vacuum meter shows that it reaches the required 30 Pa.

[0049] (2) Then, turn on the power switch of the high-frequency induction coil and start heating. The high-frequency induction coil heats up at a rate of 10°C / min. During the melting process of the indium block, argon gas is introduced for protection at a flow rate of 5 L / min, and the vacuum degree in the system is maintained at 100-200 Pa. After reaching the heating temperature of 250°C, which is the melting temperature of solid elemental indium, the indium block is completely melted to obtain indium liquid.

[0050] (3) Then turn on ultrasonic atomization, the ultrasonic frequency of ultrasonic atomization is 120kHz, the atomization pressure is 0.3MPa, the injection speed of the carrier gas is set to 40L / min, and the vacuum degree is maintained at 300pa during the atomization and oxidation process. The indium liquid in the crucible flows into the atomization tube through the pipeline and is atomized and then blown into the quartz rotating tube. At this time, the microwave heating system starts to heat the quartz rotating tube, and the heating rate is 100℃ / min. The heating temperature reaches and is maintained at 900℃, and then the motor is started. The quartz rotating tube starts to rotate at a speed of 10rpm. At this time, the oxygen valve is opened to introduce oxygen, and the oxygen injection rate is 40L / min. The indium mist is blown into the quartz rotating tube so that the oxygen and the indium mist react.

[0051] (4) Observe the situation in the quartz rotating tube until there is no indium mist in the pipe connected to the rear end of the atomizing tube and a large amount of product is deposited on the inner wall of the quartz rotating tube. Turn off the microwave heating system and stop heating. Open valve III between the quartz rotating tube and the water cooling system, stop the quartz rotating tube, increase the oxygen flow rate to 50L / min, and blow the reaction product into the perforated sieve tube; wait for the indium oxide product to enter the perforated sieve tube with an inner diameter of 60mm and a pore size of 10μm, and then fall into the bag through the pore size of the perforated sieve tube under the cooling of the 25℃ water cooling system. After cooling and adsorption by the air cooling system again, it enters the ultrafine grinder for particle size refinement and then falls into the collection box. Open the oxygen valve switch to allow O2 to enter the quartz rotating tube and the perforated sieve tube. After the vacuum gauge returns to atmospheric pressure, collect the indium oxide powder deposited in the collection box in the reaction chamber to obtain high-purity nano indium oxide powder.

[0052] The purity of high-purity nano-indium oxide powder is 99.999%. Figure 3 A scanning electron microscope image of the prepared high-purity nano-indium oxide powder shows a relatively uniform particle size around 30 nm, with no apparent agglomeration. The particle size D50 is 180 nm, and the specific surface area is 10.40 m2 / g.

[0053] Example 4

[0054] The nano-indium oxide powder preparation device described in Example 1 is used to prepare nano-indium oxide powder, comprising the following steps:

[0055] (1) Open the evaporation furnace door, place the solid elemental indium in the evaporation furnace, and place the built-in crucible on the high-frequency heating coil. Close the evaporation furnace door, turn on the vacuum pump to evacuate the vacuum, and wait until the vacuum meter shows that the required vacuum degree reaches 30Pa.

[0056] (2) Then, turn on the power switch of the high-frequency induction coil and start heating. The heating rate of the high-frequency induction coil is 8°C / min. During the melting process of the indium block, argon gas is introduced for protection at a flow rate of 5L / min. The vacuum degree in the system is maintained at 100-200Pa. After reaching the heating temperature of 200°C, which is the melting temperature of solid elemental indium, the indium block is completely melted to obtain indium liquid.

[0057] (3) Then turn on ultrasonic atomization, the ultrasonic frequency of ultrasonic atomization is 150kHz, the atomization pressure is 0.4MPa, the injection speed of the carrier gas is set to 20L / min, and the vacuum degree is maintained at 200pa during the atomization and oxidation process. The indium liquid in the crucible flows into the atomization tube through the pipeline and is atomized and then blown into the quartz rotating tube. At this time, the microwave heating system starts to heat the quartz rotating tube, and the heating rate is 120℃ / min. The heating temperature reaches and is maintained at 1000℃, and then the motor is started. The quartz rotating tube starts to rotate at a speed of 20rpm. At this time, the oxygen valve is opened to introduce oxygen, and the oxygen injection speed is 40L / min. The indium mist is blown into the quartz rotating tube so that the oxygen and the indium mist react.

[0058] (4) During the reaction, observe the situation inside the quartz rotating tube until there is no indium mist in the pipe connected to the rear end of the atomizing tube and a large amount of product is deposited on the inner wall of the quartz rotating tube. Then, turn off the microwave heating system and stop heating. Open valve III between the quartz rotating tube and the water cooling system, stop the quartz rotating tube, increase the oxygen flow rate to 50L / min, and blow the reaction product into the perforated sieve tube; wait for the indium oxide product to enter the perforated sieve tube with an inner diameter of 60mm and a pore size of 30μm, and then fall into the bag through the pores of the perforated sieve tube under the cooling of the 25℃ water cooling system. After being cooled and adsorbed again by the air cooling system, it enters the ultrafine grinder for particle size refinement and then falls into the collection box. Open the oxygen valve switch to allow O2 to enter the quartz rotating tube and the perforated sieve tube. After the vacuum gauge returns to atmospheric pressure, collect the indium oxide powder deposited in the collection box in the reaction chamber to obtain high-purity nano-indium oxide powder.

[0059] The purity of high-purity nano-indium oxide powder is 99.999%. Figure 4 A scanning electron microscope image of the prepared high-purity nano-indium oxide powder shows a uniform particle size of approximately 20 nm with no apparent agglomeration. The particle size D50 is 165 nm, and the specific surface area is 10.85 m2 / g.

[0060] Comparative Example 1

[0061] The nano-indium oxide powder preparation device described in Example 1 is used to prepare nano-indium oxide powder, comprising the following steps:

[0062] (1) Open the hatch of the evaporation furnace, place the solid elemental indium in the crucible in the evaporation furnace, and place the built-in crucible on the high-frequency heating coil. Close the hatch of the evaporation furnace, turn on the vacuum pump to evacuate the vacuum, and wait until the vacuum meter shows that the required vacuum degree reaches 30 Pa.

[0063] (2) Then, turn on the power switch of the high-frequency induction coil and start heating. The high-frequency induction coil heats up at a rate of 5°C / min. During the melting process of the indium block, argon gas is introduced for protection at a flow rate of 5 L / min, and the vacuum degree in the system is maintained at 100-200 Pa. After reaching the heating temperature of 180°C, which is the melting temperature of solid elemental indium, the indium block is completely melted to obtain indium liquid.

[0064] (3) Then, ultrasonic atomization is turned on. The ultrasonic frequency of ultrasonic atomization is 30 kHz, the atomization pressure is 0.1 MPa, and the injection rate of the carrier gas is set to 30 L / min. The indium liquid in the crucible flows into the atomization tube through the pipeline and is atomized and then blown into the quartz rotating tube. At this time, the microwave heating system starts to heat the quartz rotating tube. The heating rate is 150 ° C / min. The heating temperature reaches and is maintained at 1100 ° C. At this time, the oxygen valve is opened to introduce oxygen. The injection rate of oxygen is 40 L / min. The indium mist is blown into the quartz rotating tube so that the oxygen and the indium mist react.

[0065] (4) During the reaction, the situation inside the reaction chamber can be observed through the observation window until there is no indium mist in the pipe connected to the rear end of the atomizing tube and a large amount of product is deposited on the inner wall of the quartz rotating tube. Then, the microwave heating system is turned off and heating is stopped. Open valve III between the quartz rotating tube and the water cooling system, increase the oxygen flow rate to 50L / min, and blow the reaction product into the perforated sieve tube; after the indium oxide product enters the perforated sieve tube with an inner diameter of 60mm and a pore size of 50μm, it is cooled by a water cooling system at 25℃ and falls into the bag through the pore size of the perforated sieve tube. After being cooled and adsorbed by the air cooling system again, it enters the ultrafine grinder for particle size refinement and then falls into the collection box. Open the ball valve switch to allow O2 to enter the quartz rotating tube and the perforated sieve tube. After the vacuum gauge returns to atmospheric pressure, collect the indium oxide powder deposited in the collection box in the reaction chamber to obtain high-purity nano-indium oxide powder.

[0066] The purity of high-purity nano-indium oxide powder is 90%. Figure 5 A scanning electron microscope image of the prepared high-purity nano-indium oxide powder shows a large amount of unoxidized indium powder. The particle size ranges from about 80 nm, with uneven particle size and significant agglomeration. The particle size D50 is 220 nm, and the specific surface area is 6.88 m2 / g.

[0067] While various embodiments of the present invention have been described above, the foregoing description is intended to be illustrative, non-exhaustive, and not limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is selected to best explain the principles of the embodiments, their practical applications, or improvements to existing technologies, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A method for preparing nano-indium oxide powder, characterized in that: The steps include: (1) Melting the indium block under vacuum conditions and then atomizing it into indium liquid mist; (2) A carrier gas is introduced to blow the indium liquid mist into a quartz rotating tube for microwave heating, and then the quartz rotating tube is rotated and oxygen is introduced to react with the indium liquid mist. After the reaction is completed, indium oxide powder is obtained by cooling.

2. The method for preparing nano-indium oxide powder according to claim 1, wherein: In the step (1), the indium block is melted by heating (crucible) with a high-frequency induction coil, the melting temperature is 180-250° C., the heating rate is 5-10° C. / min; and the vacuum degree of the vacuum condition is 30-300 Pa.

3. The method for preparing nano-indium oxide powder according to claim 1, wherein: In the step (1), ultrasonic atomization is used for atomization, the ultrasonic vibration frequency is 30kHz-180kHz, and the atomization pressure is 0.1-0.5MPa.

4. The method for preparing nano-indium oxide powder according to claim 1, wherein: In the step (2), the carrier gas is argon, and the flow rate of the carrier gas is 0.5-50 L / min; the flow rate of the indium liquid mist is 0.05-0.5 L / min, and the flow rate of the oxygen is 1-100 L / min.

5. The method for preparing nano-indium oxide powder according to claim 1, wherein: The rotation speed of the quartz rotating tube is 10-30 rpm; the power of the microwave heating is 800-1500 W, the heating rate is 100-150° C. / min, and the microwave heating temperature is 900-1100° C.

6. A device for preparing nano-indium oxide powder, characterized in that: include: Evaporation furnace, oxygen tank, carrier gas tank, ultrasonic atomization tube, quartz rotary tube, water cooling system, microwave heating system, vacuum pump and recovery device; The evaporation furnace and the carrier gas tank are connected to the ultrasonic atomization tube through a pipeline. The ultrasonic atomization tube and the oxygen tank are connected to the quartz rotating tube after merging. The vacuum pump is connected to the pipeline. A microwave system is installed on the outer wall of the quartz rotating tube; the quartz rotating tube is connected to the water cooling system; and the water cooling system is connected to the recovery device.

7. The device for preparing nano-indium oxide powder according to claim 6, characterized in that: The evaporation furnace is an induction heating evaporation furnace, and the heating unit in the induction heating evaporation furnace adopts a high-frequency induction coil.

8. The device for preparing nano-indium oxide powder according to claim 6, characterized in that: The diameter of the atomization pipe of the ultrasonic atomization pipe is 1 to 1.5 cm.

9. The device for preparing nano-indium oxide powder according to claim 6, characterized in that: The inner diameter of the quartz rotating tube is 80 mm, and the outer wall of the quartz rotating tube is coated with a silicon nitride coating; the quartz rotating tube is connected to a motor, and the power of the motor is 400-2000W.

10. The device for preparing nano-indium oxide powder according to claim 6, characterized in that: A valve is provided between the water cooling system and the quartz rotating tube. The water cooling system includes a water cooling pipe, a water cooling box and a perforated sieve tube. The water cooling pipe surrounds the outer wall of the perforated sieve tube, and the inlet and outlet of the water cooling pipe are both connected to the water cooling box to form a closed circulation loop.

Images