High-temperature molten metal supercavitation pneumatic atomization cooling powder production device

Abstract

According to the device, a gas compressor, a gas heater and an atomizing gas pipe form an atomizing gas part, a cooling powder making chamber, a fan, a gas cooler and a cooling gas pipe form a cooling powder making part, and the cooling powder making chamber, the fan, the gas cooler and the cooling gas pipe form the cooling powder making part. The Venturi tube atomizer, the molten metal conveying pipe, the atomization liquid conveying pipe and the molten metal pool form an atomization part, and the molten metal pool is arranged at the lower end of a throat of the Venturi tube atomizer and communicated with the molten metal conveying pipe through the vertically-downward atomization liquid conveying pipe. High-temperature molten metal enters the molten metal pool through the molten metal conveying pipe and the atomization liquid conveying pipe, high-temperature atomization gas is accelerated to pass through the molten metal surface through the throat portion of the Venturi tube atomizer, the molten metal surface is torn off under the supercavitation effect, the molten metal is brought out, and the molten metal is diffused and atomized at a diffusion opening along with the gas to form finer liquid drops. And the atomized gas is brought into the cooling powder-making chamber and is cooled into metal powder by the cooling gas.

Description

TECHNICAL FIELD

[0001] The present application is a device for supercavitation atomization of a Venturi tube structure aerodynamic atomizer for high-temperature metal liquid, forming micro droplets and cooling to produce fine powder, belonging to the technical field of powder preparation equipment. BACKGROUND

[0002] The method of atomizing high-temperature metal liquid for powder production is mainly mechanical dispersion of metal liquid by external force. The conventional high-temperature metal liquid is sheared and dispersed by high-speed liquid or gas blowing from the side for atomization and powder production, which is a common and universal technology. The rotating disc centrifugal dispersion metal liquid into droplets for cooling and powder production represented by the published CN114951672A "Circulating cooling type high-temperature metal centrifugal atomization powder production device"; the sound wave dispersion atomization and cooling for powder production represented by the published CN118237591A "Ultrasonic atomization plasma torch powder production device with high thermal energy utilization rate", all belong to mechanical dispersion by external force.

[0003] The published CN120055273A "Device for preparing metal powder by spraying high-temperature metal liquid with high-temperature ceramic pump pressurization" discloses a device for cooling and powder production by pressurizing and atomizing metal liquid with a high-temperature ceramic pump. The high-temperature ceramic pump of the disclosed device is outside the metal liquid, the metal liquid is sucked into the pump through a pipeline and then pressurized and output, the pipeline is long, energy consumption is large, and there are many hidden dangers; during operation, the metal liquid is transported to the emergency tank and the backflow tank, the open tank body has large heat dissipation and high energy consumption, and there are many hidden dangers; in order to avoid pressure accumulation and blockage, the atomizer used can only be a large-diameter atomizer directly connected to the feeding pipe, and some still need to be diffused and atomized by external high-pressure gas, which cannot be directly atomized by pump pressure. The disclosed device solves the problem of pump pressure accumulation by using a backflow pipe, which contradicts the need for maintaining a certain pressure for atomization. Once the temperature decreases and the metal liquid solidifies, it will cause a huge hidden danger, and after the pump is stopped, the metal liquid in the feeding pipe and the backflow pipe needs to break the emergency valve at the bottom to be cleaned out. If the heat preservation fails, the metal liquid in the pump body and the pipeline will solidify, making it difficult to restart.

[0004] The pneumatic powder production equipment of the published CN200510004921.6 "Production equipment for fine metal powder" is a device that uses high-temperature and high-pressure gas flow to flow out at high speed along the outer edge of the metal liquid outlet pipe, forms negative pressure to suck out the metal liquid, and simultaneously shears or diffuses the metal liquid into droplets by high-speed gas flow, and then cools to produce powder. The metal liquid flow pressure formed by negative pressure adsorption is very low, and a 6MPa gas flow pressure can only generate a 0.03PMa negative pressure suction force on the metal liquid. Moreover, the reduction of pressure and heat absorption of high-pressure gas flow also affects the dispersion and atomization effect.

[0005] The existing high-temperature molten metal atomization method and device have high safety requirements due to the existence of high pressure, and can only have one nozzle corresponding to one set of cooling, powder making and collecting equipment, resulting in huge unit capacity investment of the equipment; the powder making process of the equipment is poor in continuous operation, the compressed gas has high pressure, large gas volume, high energy consumption and high production cost, the prepared metal powder has large particle size span, high content of coarse powder and low comprehensive added value. SUMMARY

[0006] The technical scheme for solving the above problems is to use a Venturi tube structure atomizer to establish a high-temperature molten metal pneumatic atomization powder making device, so that the heated gas contacts the high-temperature molten metal surface at the throat part of the Venturi tube atomizer, the high-speed gas flow at the throat part forms a super cavitation effect on the high-temperature molten metal surface, tears the molten metal surface to take out the surface liquid and makes the liquid diffuse with the gas at the diffusion part to form finer liquid droplets, and finally prepares fine powder after cooling.

[0007] The device is composed of an atomizing gas part, an atomizing part and a cooling and powder making part. The atomizing gas part is composed of a gas compressor (13), a gas heater (15) and an atomizing gas pipe (14). The atomizing part is composed of a Venturi tube atomizer (1), a molten metal conveying pipe (5), an atomizing liquid conveying pipe (7) and a molten metal pool (8), wherein the molten metal pool (8) is connected to the molten metal conveying pipe (5) through the atomizing liquid conveying pipe (7) vertically downward at the lower end of the throat (3) of the Venturi tube atomizer (1). The cooling and powder making part is composed of a cooling and powder making chamber (9), a fan (10), a gas cooler (11) and a cooling gas pipe (12). The atomizing gas pipe of the atomizing gas part of the device is connected to the gas inlet pipe (2) of the Venturi tube atomizer of the atomizing part, and the diffusion port (4) of the Venturi tube atomizer of the atomizing part extends into the cooling and powder making chamber and is connected thereto. One cooling and powder making chamber is connected to one or more Venturi tube atomizers. The atomizing gas pipe, the Venturi tube atomizer and the molten metal conveying pipe are made of ceramic and metal which are resistant to high temperature and metal corrosion, and have an external heat preservation layer.

[0008] The operating method of the device for the high-temperature metal liquid pneumatic atomization cooling and powder production is as follows: first, the Venturi atomizer and the metal liquid delivery pipe are horizontally placed, the high-temperature metal liquid is added into the metal liquid delivery pipe (6) and is pressurized to make the high-temperature metal liquid enter the metal liquid pool at the lower end of the throat of the Venturi atomizer along the atomization liquid delivery pipe, and the metal liquid surface of the metal liquid pool is kept flat with the lower end surface of the throat. Second, the temperature of the cooling gas cooled by the gas cooler is set, the gas cooler and the fan are started to pass the cooling gas into the cooling and powder production chamber. Third, the temperature of the atomization gas heated by the gas heater is set, the gas heater and the gas compressor are started to pass the atomization gas with pressure into the atomization pipeline and the Venturi atomizer, and the temperature of the atomization gas is higher than or equal to the melting point of the atomized metal. The atomization gas and the cooling gas are the same kind of gas. The atomization gas is accelerated through the throat of the Venturi atomizer, the high-speed airflow passes the metal liquid surface of the metal liquid pool, and the metal liquid surface is torn and taken out under the super-cavitation effect to form finer liquid droplets which are brought into the cooling and powder production chamber by the atomization gas and are cooled into solid particles by the cooling gas to prepare the metal powder with fine particle size. The atomization process replenishes the high-temperature metal liquid in the metal liquid delivery pipe to keep the metal liquid surface of the metal liquid pool flat with the lower end surface of the throat.

[0009] The device can be operated with lower gas pressure and less gas amount, is simple and safe to operate, and can prepare the powder with fine particle size and concentrated span. One cooling and powder production chamber can be connected with multiple Venturi atomizers to expand the yield of a single device, save energy and reduce cost. BRIEF DESCRIPTION OF DRAWINGS

[0010] ATTACHED Figure 1 Device structure schematic diagram

[0011] ATTACHED Figure 2 Side view of the communication structure of the Venturi atomizer and the metal liquid delivery pipe

[0012] ATTACHED Figure 3 Top view of the communication structure of the Venturi atomizer and the metal liquid delivery pipe

[0013] ATTACHED Figure 4 End view of the diffusion port of the communication structure of the Venturi atomizer and the metal liquid delivery pipe

[0014] Specific application examples

[0015] Example 1: Device for producing aluminum powder

[0016] 1. The atomizing gas part of the device is composed of a gas compressor, a gas heater and an atomizing gas pipe, the atomizing gas pipe being made of 316 steel pipe; the atomizing part is composed of a Venturi tube atomizer, an aluminum liquid conveying pipe, an atomizing liquid conveying pipe and an aluminum liquid pool, wherein the aluminum liquid pool is at the lower end of the throat of the Venturi tube atomizer and is connected to the aluminum liquid conveying pipe through the vertically downward atomizing liquid conveying pipe, the Venturi tube atomizer and the aluminum liquid conveying pipe being made of silicon nitride ceramic material; the cooling and powder making part is composed of a fan, a gas cooler, a cooling and powder making chamber and a cooling gas pipe. The device has one atomizing gas pipe connected to one Venturi tube atomizer, and the Venturi tube atomizer is connected to the cooling and powder making chamber. The atomizing gas and the cooling gas are nitrogen.

[0017] 2. The Venturi tube atomizer and the aluminum liquid conveying pipe are placed horizontally, 700℃ aluminum liquid is added into the aluminum liquid conveying pipe, and the aluminum liquid is pressurized to flow upward along the atomizing liquid conveying pipe into the aluminum liquid pool at the lower end of the throat of the Venturi tube atomizer, and the liquid surface of the aluminum liquid is kept level with the lower end surface of the throat.

[0018] 3. The gas cooler is set to output gas at a temperature of 5℃, and the gas cooler and the fan are started to introduce cooled nitrogen into the cooling and powder making chamber.

[0019] 4. The gas heater is set to output gas at a temperature of 662℃, the compressor is started to introduce 662℃ nitrogen at a pressure of 0.1MPa into the atomizing pipe and the Venturi tube atomizer, the high-temperature nitrogen is accelerated through the aluminum liquid surface of the aluminum liquid pool at the throat part of the Venturi tube atomizer under the effect of super cavitation, tears the aluminum liquid surface to take out the aluminum liquid and makes it form finer aluminum liquid droplets at the diffusion port, the aluminum liquid droplets are taken into the cooling and powder making chamber by the nitrogen, and become fine aluminum powder after being cooled by 5℃ nitrogen.

[0020] Example 2: Device for producing metal magnesium powder

[0021] 1. The atomizing gas part of the device is composed of a gas compressor, a gas heater and an atomizing gas pipe, the atomizing gas pipe being made of manganese steel pipe; the atomizing part is composed of a Venturi tube atomizer, a magnesium liquid conveying pipe, an atomizing liquid conveying pipe and a magnesium liquid pool, wherein the magnesium liquid pool is at the lower end of the throat of the Venturi tube atomizer and is connected to the magnesium liquid conveying pipe through the vertically downward atomizing liquid conveying pipe, the Venturi tube atomizer and the magnesium liquid conveying pipe being made of silicon carbide ceramic material; the cooling and powder making part is composed of a fan, a gas cooler, a cooling and powder making chamber and a cooling gas pipe. The device has one atomizing gas pipe connected to three Venturi tube atomizers, and the diffusion ports of the three Venturi tube atomizers are respectively connected to one cooling and powder making chamber. The atomizing gas and the cooling gas are argon.

[0022] 2. The Venturi tube atomizer and the magnesium liquid conveying pipe are placed horizontally, 720℃ magnesium liquid is added into the magnesium liquid conveying pipe, and the magnesium liquid is pressurized to flow upward along the atomizing liquid conveying pipe into the magnesium liquid pool at the lower end of the throat of the Venturi tube atomizer, and the liquid surface of the magnesium liquid is kept level with the lower end surface of the throat.

[0023] 3. Set the gas cooler cooling outlet gas temperature to 0℃, start the gas cooler and fan to pass into the cooling argon gas to the cooling milling chamber.

[0024] 4. Set the gas heater heating outlet gas temperature to 650℃, start the compressor to pass into the 650℃ argon gas with a pressure of 0.3MPa to the atomizing pipeline, and divide the pressure through 3 Venturi tube atomizers. The argon gas pressure entering each Venturi tube atomizer is 0.1MPa. The argon gas is accelerated through the throat part of the Venturi tube atomizer, tears the magnesium liquid surface under the super cavitation effect, and brings out the surface layer magnesium liquid and makes it atomized to form finer magnesium liquid drops at the diffusion port. The liquid drops sprayed by the 3 Venturi tube atomizers are respectively brought into 1 cooling milling chamber by the argon gas, and become fine magnesium powder after being cooled by the 0℃ argon gas.

Claims

1. A production apparatus for high-temperature molten metal supercavitation pneumatic atomization cooling and powder production, characterized in that: The device is composed of an atomizing gas part, an atomizing part and a cooling powdering part. The atomizing gas part is composed of a gas compressor, a gas heater and an atomizing gas pipe. The cooling powdering part is composed of a cooling powdering chamber, a fan, a gas cooler and a cooling gas pipe. The atomizing part is composed of a Venturi atomizer, a metal liquid conveying pipe, an atomizing liquid conveying pipe and a metal liquid pool. The metal liquid pool is connected with the metal liquid conveying pipe through the atomizing liquid conveying pipe which is vertically downward. The atomizing gas pipe of the device is connected with the gas inlet pipe of the Venturi atomizer. The diffusion port of the Venturi atomizer is connected with the cooling powdering chamber. (1) The Venturi atomizer and the metal liquid conveying pipe are horizontally placed. High temperature metal liquid is added into the metal liquid conveying pipe. The high temperature metal liquid is pressurized to enter the metal liquid pool at the lower end of the throat of the Venturi atomizer through the atomizing liquid conveying pipe. The metal liquid surface in the metal liquid pool is kept flat with the lower end surface of the throat. (2) The temperature of the gas cooled by the gas cooler is set. The gas cooler and the fan are started to pass the cooling gas into the cooling powdering chamber. (3) The temperature of the atomizing gas heated by the gas heater is set. The gas heater and the gas compressor are started to pass the atomizing gas with pressure into the atomizing pipe and the Venturi atomizer. The atomizing gas is accelerated through the throat of the Venturi atomizer. The high speed gas flow tears the metal liquid surface of the metal liquid pool under the super cavitation effect to bring out the metal liquid and make it form finer liquid drops with the gas diffusion at the diffusion port. The atomizing gas is cooled to become metal powder in the cooling powdering chamber.

2. The production device for high-temperature molten metal supercavitation aerodynamic atomization cooling and pulverization according to claim 1, characterized in that One cooling powdering chamber is connected with one or more Venturi atomizers.

3. The production device for high-temperature molten metal supercavitation aerodynamic atomization cooling and powder production according to claim 1, characterized in that The gas for atomizing and the gas for cooling are the same kind of gas. The temperature of the atomizing gas is higher than the melting point of the atomized metal.

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