A hard particle powder feeding composite liquid nitrogen atomization impact type micro-nano powder preparation device and a preparation method thereof

Abstract

This invention discloses a device and method for preparing hard particle powder using liquid nitrogen atomization and impaction. The device includes a precision powder feeding and mixing system, a graded liquid nitrogen conveying system, a liquid nitrogen atomization and collision system, a ring heating system, a micro-nano powder collection system, and a large-diameter hard particle recovery system. The method uses a powder feeding and mixing device to spray hard particles from the nozzle guide cavity. The high-pressure liquid nitrogen valve is opened, allowing liquid nitrogen to be sprayed from the high-pressure liquid nitrogen cryogenic nozzle. At the moment the hard particles are sprayed from the nozzle guide cavity, under the action of the high-pressure liquid nitrogen jet, the airflow containing the hard particles is instantly cooled, accelerated, and atomized into a scattered airflow. At this time, the brittleness of the hard particles cooled by liquid nitrogen is greatly improved. The symmetrically arranged scattered airflow will collide at high speed, and the hard particles will undergo micro-fragmentation during the collision process. During the process of the micro-fragmented hard particles falling to the bottom of the collision chamber, they are heated and collected by a particle sieving system, resulting in micro-nano powder. The hard particles then disperse to the bottom of the collision chamber. The collected medium-sized hard particles are then propelled into the nozzle guide chamber by a unidirectional nitrogen gas flow and ejected, where they undergo further cooling, acceleration, atomization, and impact. This invention offers high production efficiency, low cost, and produces micro-nano powder with a narrow particle size distribution and minimal waste, making it suitable for mass production.

Description

Technical Field

[0001] This invention belongs to the field of micro-nano powder preparation, and specifically relates to a device for preparing micro-nano powder by hard particle feeding combined with liquid nitrogen atomization impact, and provides a method for preparing micro-nano powder by hard particle feeding combined with liquid nitrogen atomization impact. Background Technology

[0002] As a functional material, micro and nano powders are widely used in key technology fields such as information technology, biotechnology, environmental technology and energy technology due to their unique physicochemical properties in mechanics, thermal, magnetic and optical aspects. They play a pivotal role in various fields of national defense and national economy. Therefore, the preparation and processing technology of ultrafine powders has always occupied a very important position in the field of powders, becoming one of the important goals of modern industrial technology development, as well as one of the important research directions with great demand and challenges.

[0003] Confrontational jet milling, a type of air jet milling, utilizes two converging jets to pulverize materials through collision. Compared to other air jet milling methods (such as target milling), it offers greater pulverizing force and a more pronounced pulverizing effect. Furthermore, since particle breakage primarily occurs through particle-to-particle collisions within the milling chamber, wear on the chamber is minimal, resulting in high product purity. However, due to the high impact energy of the jets during jet milling, the prepared powders, with their high surface activity, are highly prone to re-agglomeration.

[0004] Currently, SUGINO Corporation of Japan has developed a wet powder pulverizing device that prepares micro- and nano-powders by colliding two particle jets under pressures up to 245 MPa. However, this technology requires high pressure, is costly, and the resulting powder particle size and efficiency are not ideal.

[0005] A search of existing technical literature revealed that CN105080687 discloses an air jet milling system and powder processing technology to address the problem of nozzle clogging in air jet mills caused by sticky powder particles during the current pulverization process. It proposes using an air chiller to reduce the temperature of compressed air, thereby ensuring that the composition and efficacy of the powder remain unchanged. CN206184572U provides a closed-loop gas circulation low-temperature energy-saving air jet milling device for powder materials such as heat-sensitive materials, chemical raw materials (plastics, resins), and tough materials (traditional Chinese medicine), which are easily cooled at low temperatures and can be produced on a large scale for extended periods. CN114588986A addresses the problems of agglomeration and oxidation in existing powder-making devices by designing a low-temperature assisted air jet milling device. By combining air jet milling with low-temperature assistance, it significantly improves the brittleness of the powder raw materials, enhancing the pulverization effect and efficiency during high-speed collisions between particles. However, all of the above methods suffer from low particle impact kinetic energy and a small effective impact area. Therefore, improvements to existing low-temperature assisted air jet milling methods and devices are particularly necessary. Summary of the Invention

[0006] To address the problems of high process cost, uneven particle size distribution of micro / nano powders, and unsatisfactory preparation efficiency in traditional airflow pulverization methods, the inventors have developed a hard particle feeding composite liquid nitrogen atomization impact-type micro / nano powder preparation device and its preparation method. The invention adopts the following technical solution: The hard particle feeding composite liquid nitrogen atomization impact-type micro / nano powder preparation device includes a precision powder feeding and mixing system 31, a high-speed liquid nitrogen conveying system 3, a liquid nitrogen atomization collision system 12, a micro / nano powder collection system 18, and a large-diameter hard particle recovery system 27; the precision powder feeding and mixing system 31 includes: a nitrogen cylinder group 1, a nitrogen valve 2, a precision powder feeder 5, a dry nitrogen pressure regulator 7, a nitrogen pipe 9, an annular nitrogen nozzle 10, a large-diameter hard particle conveying pipe 40, and a quick connector 38. The system includes: a large-diameter hard particle guide pipe 35; a nitrogen valve 2 with one end installed on the nitrogen cylinder group 1 and the other end connected to the precision powder feeder 5 via a nitrogen pipe 9; the outlet of the precision powder feeder 5 connected to the large-diameter hard particle guide pipe 35 via a large-diameter hard particle conveying pipe 40 and a quick connector 38; dry nitrogen in the nitrogen cylinder group 1 connected to the annular nitrogen nozzle 10 via the nitrogen pipe 9; and a high-speed liquid nitrogen delivery system 3 including: a liquid nitrogen tank 30, a high-speed liquid nitrogen pump 29, a liquid nitrogen one-way valve 4, a liquid nitrogen inlet 8 in the atomizing collision chamber interlayer, a liquid nitrogen outlet 13 in the atomizing collision chamber interlayer, a high-speed liquid nitrogen delivery pipe 32, and a high-speed liquid nitrogen delivery pipe two-way connector 33; liquid nitrogen in the liquid nitrogen tank 30 enters the atomizing collision chamber through the liquid nitrogen inlet 8 in the atomizing collision chamber interlayer. The liquid nitrogen flows out from the liquid nitrogen outlet 13 of the atomizing collision chamber 47; the liquid nitrogen in the liquid nitrogen tank 30 is mixed with the liquid nitrogen flowing out from the liquid nitrogen outlet 13 of the atomizing collision chamber and returning through the liquid nitrogen one-way valve 4, and flows to the high-speed liquid nitrogen pump 29; the liquid nitrogen accelerated by the high-speed liquid nitrogen pump 29 is transported to the liquid nitrogen atomizing nozzle 39 through the high-speed liquid nitrogen delivery pipe 32 and the high-speed liquid nitrogen delivery pipe two-way connector 33 respectively; the liquid nitrogen atomizing collision system 12 includes: liquid nitrogen atomizing nozzle 39, liquid nitrogen atomizing nozzle nozzle 34, liquid nitrogen atomizing nozzle support 37, transmission screw 43, motor 42, liquid nitrogen atomizing collision system support 41, guide shaft 36, liquid nitrogen atomizing collision area 44, hard particles after impact 45, annular heating system 11, and heated dry After impact, hard particles 46 are formed; motor 42 is mounted on liquid nitrogen atomization collision system bracket 41, and liquid nitrogen atomization nozzle 39 is connected to the main drive screw 43 of motor 42 through liquid nitrogen atomization nozzle bracket 37; liquid nitrogen atomization nozzle bracket 37 maintains a relative motion relationship with liquid nitrogen atomization collision system bracket 41 through guide shaft 36; micro-nano powder collection system 18 includes: micro-nano powder exhaust collection pipe 14, blower 15, micro-nano powder exhaust collection chamber 16, micro-nano powder collector 17, and micro-nano powder material 19; one end of micro-nano powder exhaust collection pipe 14 is connected to hard particle separation chamber 21, and the other end is connected to micro-nano powder exhaust collection chamber 16 through blower 15; micro-nano powder collector 17 is installed at the lower end of micro-nano powder exhaust collection chamber 16;The large-diameter hard particle recovery system 27 includes: a hard particle separation chamber interlayer air outlet 20, a hard particle separation chamber 21, a large-particle hard particle recovery system 22, a large-diameter hard particle recovery conveying pipe 23, a large-particle hard particle recovery precision powder feeding system 24, a large-particle hard particle recovery conveying nitrogen pressure regulator 25, a large-particle hard particle recovery conveying nitrogen one-way valve 26, a powder mixing gas pipe one-way valve 6, and a hard particle separation chamber interlayer air supply nitrogen pressure regulator 28; the nitrogen cylinder group 1 is connected to the hard particle separation chamber interlayer air outlet 20 via a nitrogen valve 2, a nitrogen pipe 9, and the hard particle separation chamber interlayer air supply nitrogen pressure regulator 28.

[0007] The aforementioned method for preparing hard particle powder using liquid nitrogen atomization impactor micro / nano powder involves using a powder feeding device to eject large-diameter hard particles from a nozzle guide chamber; liquid nitrogen is ejected from a high-pressure, low-temperature liquid nitrogen nozzle; at the instant the hard particles are ejected from the nozzle guide chamber, under the action of the high-pressure liquid nitrogen jet, the airflow containing the large-diameter hard particles is instantly cooled, accelerated, and atomized into a scattered airflow stream; at this time, the brittleness of the large-particle hard abrasive is greatly improved after being cooled by liquid nitrogen: the symmetrically arranged scattered airflow streams will collide at high speed, and the large-particle hard abrasive will undergo micro-fragmentation during the collision. As the micro-fragmented abrasive particles fall to the bottom of the collision chamber, they are heated and collected by a dust removal system, while the large-particle hard abrasive will scatter to the bottom of the collision chamber; the collected large-particle hard abrasive is then carried by a unidirectional airflow to the nozzle guide chamber for ejection, where it undergoes cooling, acceleration, atomization, and impact again.

[0008] The method for preparing hard particle powder by liquid nitrogen atomization impact type micro-nano powder involves controlling the distance between two liquid nitrogen atomizing nozzles (39) to 50~350mm before preparing micro-nano powder by using a motor (42); loading large-diameter hard particles into a precision powder feeder (5); opening the nitrogen valve (2) of the nitrogen cylinder group (1); adjusting the pressure threshold of the drying nitrogen pressure regulator (7), the nitrogen pressure regulator (25) for recovering large-diameter hard particles, and the nitrogen pressure regulator (28) for supplying air to the jacket of the hard particle separation chamber; and opening the precision powder feeding system (24), the blower (15), and the annular heating system (11) for recovering large-diameter hard particles to establish a stable dry gas atmosphere in the hard particle separation chamber (21). During the preparation of micro-nano powders, the power supply of the precision powder mixer (5) is turned on, and large-diameter hard particles are injected into the liquid nitrogen atomizing nozzle (39) through the large-diameter hard particle conveying pipe (40) and the large-diameter hard particle guide pipe (35); the power supply of the high-speed liquid nitrogen pump (29) is turned on, the liquid nitrogen tank (30) is opened, and liquid nitrogen is injected into the liquid nitrogen inlet (8) of the atomizing collision chamber jacket and the high-speed liquid nitrogen pump (29) respectively; after being accelerated by the liquid nitrogen pump (29), the liquid nitrogen is injected into the hard particle separation chamber (21) respectively. The liquid nitrogen is sprayed from the liquid nitrogen atomizing nozzles (39) on both sides of the liquid nitrogen atomizing nozzle (34); the high-speed liquid nitrogen sprayed from the liquid nitrogen atomizing nozzle (34) cools, atomizes and accelerates the large-diameter hard particles sprayed from the large-diameter hard particle guide tube (35), thereby increasing the scattering area and impact kinetic energy of the large-diameter hard particle flow and significantly improving its brittleness. The large-diameter hard particles cooled by liquid nitrogen are impacted and broken, thereby preparing micro-nano powder materials (19). After the micro-nano powder is prepared, turn off the power supply of the precision powder feeder (5), the nitrogen valve (2) of the nitrogen cylinder group (1), the power supply of the high-speed liquid nitrogen pump (29), the liquid nitrogen tank (30), the precision powder feeding system (24) for recovering large-diameter hard particles, and the ring heating system (11) in sequence. After the machine is shut down for 2 hours, turn off the blower (15). After taking out the micro-nano powder collector (17) from the micro-nano powder collection system (18), the micro-nano powder material (19) can be obtained.

[0009] The hard particle powder feeding composite liquid nitrogen atomization impact-type micro / nano powder preparation device and its preparation method of the present invention have the following advantages and effects: 1. Liquid nitrogen cooling is used in the preparation process of this micro-nano powder, which greatly improves the brittleness of large-diameter hard abrasive particles and solves the key technical problem of low impact crushing efficiency of large-diameter hard abrasive particles in the traditional airflow pulverization micro-nano powder preparation process. 2. The use of liquid nitrogen cooling effectively reduces the probability of agglomeration of micro / nano powders due to surface charge accumulation during preparation. Furthermore, it effectively prevents oxidation caused by the increased temperature during impact with hard abrasive particles. 3. In the preparation of micro and nano powders, large-diameter hard abrasive particles can effectively increase the impact area and improve their impact efficiency under high-speed liquid nitrogen atomization. 4. During the preparation of micro and nano powders, hard particles that do not meet the particle size requirements can be recycled and subjected to cyclic impact powdering. 5. While ensuring that the prepared micro-nano powders have good working performance, the production cost is effectively reduced and the preparation efficiency is improved, which is conducive to industrial production and promotion. Attached Figure Description

[0010] Figure 1 This is a schematic diagram of the overall structure of the large-diameter hard particle feeding composite liquid nitrogen atomization impact micro-nano powder preparation device used in this invention. Figure 1 This is a flowchart illustrating the principle of the present invention.

[0011] Figure 2 for Figure 1 A magnified view of part A in the image.

[0012] The components are: 1-Nitrogen cylinder group, 2-Nitrogen valve, 3-Stage liquid nitrogen delivery system, 4-Liquid nitrogen check valve, 5-Precision powder mixer, 6-Powder mixing gas pipe check valve, 7-Drying nitrogen pressure regulator, 8-Liquid nitrogen inlet of atomizing collision chamber, 9-Nitrogen pipe, 10-Annular nitrogen nozzle, 11-Annular heating system, 12-Liquid nitrogen atomizing collision system, 13-Liquid nitrogen outlet of atomizing collision chamber, 14-Micro / nano 15-Powder exhaust and collection pipe, 16-Blower, 17-Micro-nano powder exhaust and collection chamber, 18-Micro-nano powder collector, 19-Micro-nano powder collection system, 20-Micro-nano powder material, 21-Hard particle separation chamber jacketed air outlet, 22-Recovering large hard particles, 23-Recovering large-diameter hard particle conveying pipe, 24-Recovering large-diameter hard particle precision powder feeding system, 25-Recovering 26-Nitrogen pressure regulator for conveying large-diameter hard particles; 27-One-way valve for conveying nitrogen to recover large-diameter hard particles; 28-Nitrogen pressure regulator for supplying air to the interlayer of hard particle separation chamber; 29-High-speed liquid nitrogen pump; 30-Liquid nitrogen tank; 31-Precision powder feeding and mixing system; 32-High-speed liquid nitrogen delivery pipe; 33-Two-way connector for high-speed liquid nitrogen delivery pipe; 34-Liquid nitrogen atomizing nozzle nozzle; 35-Large-diameter hard particle guide pipe; 36-Guide shaft; 37-Liquid nitrogen atomizing nozzle bracket; 38-Quick connector; 39-Liquid nitrogen atomizing nozzle; 40-Large-diameter hard particle delivery pipe; 41-Liquid nitrogen atomizing collision system bracket; 42-Motor; 43-Drive screw; 44-Liquid nitrogen atomizing collision area; 45-Hard particles after impact; 46-Hard particles after impact that have been heated and dried; 47-Atomizing collision chamber interlayer. Detailed Implementation

[0013] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0014] Figure 1 This is a schematic diagram of the overall structure of the large-diameter hard particle feeding composite liquid nitrogen atomization impact micro-nano powder preparation device used in this invention, including a precision powder feeding and mixing system 31, a high-speed liquid nitrogen conveying system 3, a liquid nitrogen atomization collision system 12, a micro-nano powder collection system 18, and a large-diameter hard particle recovery system 27.

[0015] Figure 2 yes Figure 1 A partial enlarged view of section A includes the liquid nitrogen atomizing nozzle 39, the liquid nitrogen atomizing collision system support 37, and the annular heating system 11.

[0016] A method for preparing large-diameter hard particle powder using liquid nitrogen atomization impaction technology involves the following steps: Step 1: Before preparing the micro-nano powder, the distance between the two liquid nitrogen atomizing nozzles 39 is controlled to be 50~350mm by the motor 42; large-diameter hard particles are loaded into the precision powder feeder 5; the nitrogen valve 2 of the nitrogen cylinder group 1 is opened, and the pressure thresholds of the drying nitrogen pressure regulator 7, the large-diameter hard particle recovery conveying nitrogen pressure regulator 25, and the hard particle separation chamber jacket air supply nitrogen pressure regulator 28 are adjusted; the large-diameter hard particle recovery precision powder feeding system 24, the blower 15 and the annular heating system 11 are opened to establish a stable dry gas atmosphere in the hard particle separation chamber 21; Step Two: During the preparation of micro / nano powders, the power supply to the precision powder mixer 5 is turned on, and large-diameter hard particles are injected into the liquid nitrogen atomizing nozzle 39 through the large-diameter hard particle conveying pipe 40 and the large-diameter hard particle guide pipe 35; the power supply to the high-speed liquid nitrogen pump 29 is turned on, the liquid nitrogen tank 30 is opened, and liquid nitrogen is injected into the liquid nitrogen inlet 8 of the atomizing collision chamber jacket and the high-speed liquid nitrogen pump 29 respectively; after being accelerated by the liquid nitrogen pump 29, the liquid nitrogen is injected into the two hard particle separation chambers 21 respectively. The liquid nitrogen is atomized in the side of the liquid nitrogen atomizing nozzle 39 and ejected from the liquid nitrogen atomizing nozzle nozzle 34; the high-speed liquid nitrogen ejected from the liquid nitrogen atomizing nozzle nozzle 34 cools, atomizes and accelerates the large-diameter hard particles ejected from the large-diameter hard particle guide tube 35, thereby increasing the scattering area and impact kinetic energy of the large-diameter hard particle flow and significantly improving its brittleness; the large-diameter hard particles cooled by liquid nitrogen are crushed by impact, thereby preparing micro-nano powder material 19; Step 3: After the micro-nano powder is prepared, turn off the power supply of the precision powder feeder 5, the nitrogen valve 2 of the nitrogen cylinder group 1, the power supply of the high-speed liquid nitrogen pump 29, the liquid nitrogen tank 30, the precision powder feeding system 24 for recovering large-diameter hard particles, and the annular heating system 11 in sequence; after the machine has been shut down for 2 hours, turn off the blower 15; after taking out the micro-nano powder collector 17 from the micro-nano powder collection system 18, the micro-nano powder material 19 can be obtained.

[0017] For those skilled in the art, any changes, modifications, substitutions, and variations made to the embodiments without departing from the principles and spirit of the present invention, based on the teachings of the present invention, still fall within the protection scope of the present invention.

Claims

1. A device for preparing micro / nano powders by combining hard particle feeding with liquid nitrogen atomization and impaction, characterized in that: The device includes a precision powder feeding and mixing system (31), a graded liquid nitrogen delivery system (3), a liquid nitrogen atomization collision system (12), a micro-nano powder collection system (18), and a large-diameter hard particle recovery system (27). The precision powder feeding and mixing system (31) includes: a nitrogen cylinder group (1), a nitrogen valve (2), a precision powder feeder (5), a drying nitrogen pressure regulator (7), a nitrogen pipe (9), an annular nitrogen nozzle (10), a large-diameter hard particle conveying pipe (40), a quick connector (38), and a large-diameter hard particle guide pipe (35); one end of the nitrogen valve (2) is installed on the nitrogen cylinder group (1), and the other end is connected to the precision powder feeder through the nitrogen pipe (9). The powder mixer (5) is connected; the outlet end of the precision powder mixer (5) is connected to the large-diameter hard particle guide pipe (35) through the large-diameter hard particle conveying pipe (40) and quick connector (38), and the large-diameter hard particles are injected into the liquid nitrogen atomizing nozzle (39) through the large-diameter hard particle conveying pipe (40) and the large-diameter hard particle guide pipe (35); the dry nitrogen in the nitrogen cylinder group (1) is connected to the annular nitrogen spray pipe (10) through the nitrogen gas pipe (9); The staged liquid nitrogen delivery system (3) includes: a liquid nitrogen tank (30), a high-speed liquid nitrogen pump (29), a liquid nitrogen check valve (4), a liquid nitrogen inlet (8) in the atomizing collision chamber interlayer, a liquid nitrogen outlet (13) in the atomizing collision chamber interlayer, a high-speed liquid nitrogen delivery pipe (32), and a high-speed liquid nitrogen delivery pipe tap (33); the liquid nitrogen in the liquid nitrogen tank (30) enters the atomizing collision chamber interlayer (47) through the liquid nitrogen inlet (8). Then, the liquid nitrogen flows out from the liquid nitrogen outlet (13) of the atomizing collision chamber jacket; the liquid nitrogen in the liquid nitrogen tank (30) is mixed with the liquid nitrogen flowing out from the liquid nitrogen outlet (13) of the atomizing collision chamber jacket and returning through the liquid nitrogen one-way valve (4), and flows to the high-speed liquid nitrogen pump (29); the liquid nitrogen accelerated by the high-speed liquid nitrogen pump (29) is transported to the liquid nitrogen atomizing nozzle (39) through the high-speed liquid nitrogen delivery pipe (32) and the staged liquid nitrogen delivery pipe two-way connector (33) respectively. The liquid nitrogen atomization collision system (12) includes: a liquid nitrogen atomization nozzle (39), a liquid nitrogen atomization nozzle outlet (34), a liquid nitrogen atomization nozzle bracket (37), a transmission screw (43), a motor (42), a liquid nitrogen atomization collision system bracket (41), a guide shaft (36), a liquid nitrogen atomization collision area (44), impacted hard particles (45), an annular heating system (11), and impacted hard particles (46) after heating and drying; the motor (42) is installed on the liquid nitrogen atomization collision system bracket (41), and the liquid nitrogen atomization nozzle (39) is connected to the transmission screw (43) of the motor (42) through the liquid nitrogen atomization nozzle bracket (37); the liquid nitrogen atomization nozzle bracket (37) maintains a relative motion relationship with the liquid nitrogen atomization collision system bracket (41) through the guide shaft (36).

2. The micro-nano powder preparation method of the hard particle powder feeding composite liquid nitrogen atomization impact micro-nano powder preparation device according to claim 1, characterized in that... The steps are as follows: Step 1: Before preparing the micro-nano powder, the distance between the two liquid nitrogen atomizing nozzles (39) is controlled to be 50~350 mm by the motor (42); the hard particles are loaded into the precision powder feeder (5); the nitrogen valve (2) of the nitrogen cylinder group (1) is opened, and the pressure threshold of the drying nitrogen pressure regulator (7), the recovery hard particle conveying nitrogen pressure regulator (25), and the hard particle separation chamber jacket air supply nitrogen pressure regulator (28) is adjusted; the large-diameter hard particle precision powder feeding system (24), the blower (15) and the ring heating system (11) are turned on to establish a stable dry gas atmosphere in the hard particle separation chamber (21); Step 2: During the preparation of micro / nano powders, the power supply to the precision powder mixer (5) is turned on, and the hard particles are injected into the liquid nitrogen atomizing nozzle (39) through the hard particle conveying pipe (40) and the hard particle guide pipe (35); the power supply to the high-speed liquid nitrogen pump (29) is turned on, the liquid nitrogen tank (30) is opened, and liquid nitrogen is injected into the liquid nitrogen inlet (8) of the atomizing collision chamber jacket and the high-speed liquid nitrogen pump (29) respectively; after the liquid nitrogen is accelerated by the liquid nitrogen pump (29), it is injected into the hard particle separation chamber ( 21) Liquid nitrogen is atomized in the nozzles (39) on both sides and sprayed out from the nozzle (34); the high-speed liquid nitrogen sprayed out from the nozzle (34) cools, atomizes and accelerates the hard particles sprayed out from the large-diameter hard particle guide tube (35), thereby increasing the scattering area and impact kinetic energy of the hard particle flow and significantly improving its brittleness; the hard particles cooled by liquid nitrogen are crushed by impact, thereby preparing micro-nano powder materials (19). Step 3: After the micro-nano powder is prepared, turn off the power supply of the precision powder feeder (5), the nitrogen valve (2) of the nitrogen cylinder group (1), the power supply of the high-speed liquid nitrogen pump (29), the liquid nitrogen tank (30), the precision powder feeding system for recovering hard particles (24), and the ring heating system (11) in sequence; after the machine is shut down for 2 hours, turn off the blower (15); after taking out the micro-nano powder collector (17) from the micro-nano powder collection system (18), the micro-nano powder material (19) can be obtained.

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