A device and method for continuous automated production of micro-nano metal powders

Abstract

The present invention discloses a continuous automated production device for micro-nano metal powder and a method thereof. The present invention comprises an ultrasonic atomization system, a high-temperature pyrolysis system, a product collection system and an exhaust gas treatment system connected in sequence; the product collection system comprises a physical separation device and an electrostatic-magnetic field coordinated adsorption device; the electrostatic-magnetic field coordinated adsorption device comprises an electrostatic collection device and a magnetic field adsorption device arranged outside the electrostatic collection device; the electrostatic collection device comprises a positive electrode electric field arrangement mechanism and a negative electrode electric field arrangement mechanism, the positive electrode electric field arrangement mechanism is arranged inside the cylindrical inner cavity of the negative electrode electric field arrangement mechanism; the positive electrode electric field arrangement mechanism comprises a trunk and a plurality of positive electrode sheets distributed along the trunk axial direction. The present invention collects metal powders by means of physical separation, high-voltage static electricity and magnetic field coordination, effectively solving the problem that nano- and micron-level fine powders are easy to leak and difficult to collect, improving the collection rate of powders, and ensuring the effective recycling of products.

Description

Technical Field

[0001] The present invention relates to the field of preparing magnetic material powders, and in particular to a device and method for continuously automatically producing micro-nano metal powders, which are suitable for preparing micro-nano metal powders with high uniformity and high dispersion by high-temperature spray pyrolysis. Background Art

[0002] In the fields of battery materials, catalysts and magnetic materials, metal micro-nano powders have important applications due to their unique chemical and physical properties. Traditionally, the preparation methods of these micro-nano powders mainly include chemical deposition, physical vapor deposition and mechanical alloying. Although the chemical deposition method can be carried out at a lower temperature, it usually faces the problems of slow reaction rate, difficult to control product dispersion and purity. In addition, the chemical reagents used in the chemical deposition method are often harmful to the environment. Although the physical vapor deposition method can produce high-purity metal powders, its equipment cost is high and the production efficiency is low. It is generally only suitable for the laboratory stage and is not suitable for large-scale production. Although the mechanical alloying method is simple in process and relatively low in cost, it often introduces inevitable impurities, and the thermal stability and chemical uniformity of the powder are difficult to guarantee.

[0003] In view of the limitations of the above methods, there is an urgent need for a new method in this field that can control costs while improving the purity and uniformity of metal powders and can be mass-produced. In addition, environmental considerations are increasingly becoming an important driving force for the development of new methods, especially reducing the use of harmful chemicals and increasing the recovery rate of materials.

[0004] To this end, we proposed a continuous automated production device for preparing highly uniform and highly dispersed micro-nano metal powders using a high-temperature spray pyrolysis method. This method is expected to show obvious advantages in improving production efficiency, controlling product particle size uniformity, and improving environmental friendliness, aiming to solve the core problems that traditional methods cannot overcome. Summary of the invention

[0005] The purpose of the present invention is to provide a device and method for continuously automating the production of micro-nano metal powders in view of some deficiencies in the prior art.

[0006] In a first aspect, the present invention provides a metal micro-nano powder continuous automated production device comprising an ultrasonic atomization system, a high-temperature pyrolysis system, a product collection system and an exhaust gas treatment system connected in sequence;

[0007] The ultrasonic atomization system comprises a solution loading container and an ultrasonic atomizer located at the bottom of the solution loading container; wherein the solution loading container comprises a container body and a plurality of high sound-transmitting membranes arranged at the bottom of the container body; the high sound-transmitting membranes face the ultrasonic atomizer;

[0008] The inlet of the solution loading container is connected to the metal salt dissolving conveying device, and the outlet is connected to the inlet of the high temperature pyrolysis system;

[0009] The high-temperature pyrolysis system adopts a tubular furnace, which includes three temperature zones with segmented temperature control; the outlet of the high-temperature pyrolysis system is connected to the inlet of the product collection system;

[0010] The product collection system comprises a physical separation device and an electrostatic-magnetic field cooperative adsorption device; the inlet of the physical separation device serves as the inlet of the product collection system, and the outlet is connected to the inlet of the electrostatic-magnetic field cooperative adsorption device; the gas outlet of the electrostatic-magnetic field cooperative adsorption device is connected to the gas inlet of the tail gas treatment system;

[0011] The electrostatic-magnetic field cooperative adsorption device comprises an electrostatic collection device and a magnetic field adsorption device arranged outside the electrostatic collection device;

[0012] The electrostatic collection device comprises a positive pole electric field arrangement mechanism and a negative pole electric field arrangement mechanism. The negative pole electric field arrangement mechanism adopts a cylindrical structure, and the positive pole electric field arrangement mechanism is arranged inside the cylindrical inner cavity of the negative pole electric field arrangement mechanism.

[0013] Preferably, there is a distance between the positive electrode electric field arrangement mechanism and the negative electrode electric field arrangement mechanism.

[0014] Preferably, the positive electric field arrangement mechanism includes a trunk and N positive electrode sheets distributed axially along the trunk; the trunk is distributed axially from the inlet of the electrostatic collection device to the gas outlet; in the axial direction from the inlet of the electrostatic collection device to the gas outlet, the sizes of the n1 positive electrode sheets located on the trunk close to the inlet of the electrostatic collection device gradually increase; the sizes of the n2 positive electrode sheets located on the trunk close to the inlet of the electrostatic collection device are the same; n1≥1, n2≥1, n1+n2=N.

[0015] Preferably, the positive electrode sheet is a circular sheet with a serrated edge structure.

[0016] Preferably, the metal micro-nano powder continuous automated production device further comprises a solution control system; the solution control system is used to control the liquid level of the solution in the solution loading container.

[0017] Preferably, the metal micro-nano powder continuous automated production device further comprises a gas flow stabilizer; the gas flow stabilizer is used to control the flow rate of the carrier gas in the solution loading container.

[0018] Preferably, the magnetic field strength of the magnetic field adsorption device is 0.01-0.2 T, and the voltage of the electrostatic collection device is 20-120 KV.

[0019] Preferably, a catalyst is provided in the exhaust gas treatment system, and the catalyst includes at least one of a platinum-palladium catalyst, an SCR catalyst, a vanadium-titanium catalyst, a copper-based catalyst, an iron-based catalyst, a cerium-zirconium catalyst and a manganese oxide catalyst.

[0020] Preferably, in the axial direction from the inlet to the outlet of the tube furnace, the length ratio of the three temperature zones is 1-2:1:1.

[0021] In a second aspect, the present invention provides a method for continuous automated production of micro-nano metal powders, specifically:

[0022] Atomizing the metal salt solution to a micron or submicron level to obtain atomized droplets;

[0023] The atomized droplets are brought into a preheated tubular furnace by a carrier gas to cause dehydration reaction and pyrolysis oxidation reaction; wherein the three temperature zones of the tubular furnace are 300-400°C, 700-800°C, and 800-1000°C respectively;

[0024] The products of the tubular furnace are collected through physical separation, electrostatic adsorption and magnetic field adsorption to obtain the precursor powder of the magnetic material, and the tail gas is discharged after being treated by the tail gas treatment system.

[0025] Preferably, the metal in the metal salt is at least one of lithium, beryllium, sodium, magnesium, aluminum, potassium, calcium, scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, gallium, silver, cadmium, indium, tin and lanthanum elements.

[0026] Compared with the prior art, the beneficial effects of the present invention include at least:

[0027] The present invention collects metal powders by means of physical separation, high-voltage static electricity and magnetic field coordination, effectively solving the problem that nano- and micron-sized fine powders are easy to leak and difficult to collect, improving the collection rate of powders and ensuring effective recycling of products.

[0028] The various systems and components of the present invention are reasonably designed, such as the structure of the solution loading container in the ultrasonic atomization system, the selection of high sound-transmitting diaphragm material, the setting of the tubular furnace temperature zone in the high-temperature pyrolysis system, the design of the physical separation device and the electrostatic-magnetic field coordinated adsorption device in the product collection system, and the setting of auxiliary components such as the gas stabilizer and the solution control system, which together ensure the high efficiency, stability and controllability of the production process and help to achieve continuous automated production.

[0029] The preparation method of the present invention has a simple process, is helpful for studying the performance of micro-nano metal powders with high uniformity and high dispersion, solves the agglomeration problem and powder uniformity problem of micro-nano metal powders, can obtain nano-scale particle products with uniform particles, no agglomeration and good dispersion, and is conducive to the large-scale production of metal powders with high uniformity and high dispersion. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a schematic diagram of the overall structure of the continuous automated production device for micro-nano metal powders.

[0031] Figure 2 This is a schematic diagram of the ultrasonic atomization system structure.

[0032] Figure 3 Schematic diagram of the solution loading container structure.

[0033] Figure 4 Schematic diagram of the ultrasonic atomizer structure.

[0034] Figure 5 Schematic diagram of the product collection system structure, where (a) is the overall device and (b) is the electrostatic-magnetic field cooperative adsorption device.

[0035] Figure 6 Schematic diagram of the exhaust gas treatment device.

[0036] Figure 7 (a) is a scanning electron microscope image of 10 um micro-nano metal powder in Example 1.

[0037] Figure 7 (b) is a scanning electron microscope image of the 3um micro-nano metal powder of Example 1.

[0038] Figure 7 (c) is a scanning electron microscope image of 5um micro-nano metal powder in Example 2.

[0039] Figure 7 (d) is a scanning electron microscope image of 2um micro-nano metal powder in Example 3.

[0040] Figure 8 (a) is a schematic diagram of the second arrangement of the positive electrode sheet in the positive electrode electric field arrangement mechanism.

[0041] Figure 8 (b) is a schematic diagram of the third arrangement of the positive electrode sheet in the positive electrode electric field arrangement mechanism.

[0042] Fig. 9 This is the XRD spectrum of the micro-nano metal powder in Example 3.

[0043] Markings in the figure: 1. Ultrasonic atomization system; 11. Solution loading container; 111. Container body; 112. High sound permeability diaphragm; 113. First firmware; 114. Second firmware; 12. Ultrasonic atomizer; 2. High-temperature pyrolysis system; 3. Product collection system; 31. Physical separation device; 311. Inlet; 312. Outlet; 313. Exhaust gas outlet; 32. Electrostatic collection device; 321. Positive electrode electric field arrangement mechanism; 3211. Main trunk; 3212. Positive electrode sheet; 322. Negative electrode electric field arrangement mechanism; 33. Magnetic field adsorption device. DETAILED DESCRIPTION

[0044] As can be seen from the background technology, the chemical reagents used in the existing preparation methods of micro-nano powders, such as chemical deposition methods, are often harmful to the environment. If the physical vapor deposition method is used, the equipment cost is high and the production efficiency is low. It is generally only applicable to the laboratory stage and is not suitable for large-scale production. If the mechanical alloying method is used, inevitable impurities are introduced, and the thermal stability and chemical uniformity of the powder are difficult to guarantee.

[0045] Therefore, at least one embodiment provides a novel micro-nano metal powder continuous automated production device, see Figure 1 , including an ultrasonic atomization system 1, a high-temperature pyrolysis system 2, a product collection system 3 and an exhaust gas treatment system connected in sequence;

[0046] See also Figure 2 The ultrasonic atomization system 1 includes a solution loading container 11 and an ultrasonic atomizer 12 located at the bottom of the solution loading container 11 (see Figure 4 ); see Figure 3 The solution loading container 11 includes a container body 111 and a plurality of highly sound-transmissive diaphragms 112 arranged at the bottom of the container body 111; the container body 111 is made of acid-resistant, alkali-resistant and corrosion-resistant materials, such as specific plastic or glass materials, to ensure that no chemical reaction occurs when the metal salt solution is loaded, thereby ensuring the stability and purity of the solution and extending the service life of the container.

[0047] Each high sound-permeable diaphragm 112 is fixed by a first fixture 113 and a second fixture 114 that cooperate with each other, and the high sound-permeable diaphragm 112 is exposed and faces the ultrasonic atomizer 12; the diaphragm material can be selected from polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate, polymethyl methacrylate, polyurethane, polystyrene, polytetrafluoroethylene, polycarbonate or ethylene-vinyl acetate copolymer, etc., and its thickness is preferably 0.1-0.5mm, such as 0.1mm, 0.2mm, 0.3mm, 0.4mm or 0.5mm. While ensuring good sound permeability, the diaphragm of this thickness range has sufficient mechanical strength to withstand the pressure of the solution and the action of ultrasonic vibration without breaking. The high sound permeability of the diaphragm allows the ultrasonic wave generated by the ultrasonic atomizer 12 to penetrate effectively, atomizing the solution into micron- or submicron-sized droplets.

[0048] The ultrasonic atomizer 12 is located at the bottom of the solution loading container 11, and its operating frequency is 20kHz-3MHz. In a preferred embodiment, the ultrasonic atomizer 12 is also equipped with a water circulation cooler, which can dynamically maintain the atomizer operating temperature and the temperature of the atomized solution in the optimal range of 20-35°C. Maintaining a suitable temperature is crucial to the atomization process. Too high or too low a temperature may affect the atomization effect and the stability of the solution. For example, when the temperature is too high, the solution may evaporate or chemically react, affecting the concentration and composition of the metal salt; too low a temperature may cause the solution viscosity to increase, which is not conducive to atomization to form uniform droplets.

[0049] The inlet of the solution loading container 11 is connected to a metal salt dissolving conveying device for conveying the prepared metal salt solution into the container, and the outlet is connected to the inlet of the high-temperature pyrolysis system 2. Polytetrafluoroethylene pipe fittings are selected at the connection. Such pipe fittings have good corrosion resistance and chemical stability, and can prevent the solution from reacting with the pipe fittings during the transmission process to contaminate the solution or affect the life of the pipeline. In addition, the metal micro-nano powder continuous automated production device may also include a solution control system for accurately controlling the liquid level of the solution in the solution loading container 11, for example, controlling the liquid level within the range of 0.2-1cm. The appropriate liquid level can ensure that the ultrasonic atomizer 12 operates under stable working conditions and ensure the consistency and stability of the atomization effect.

[0050] The high-temperature pyrolysis system 2 adopts a tubular furnace, which includes three temperature zones with segmented temperature control. The tubular furnace adopts a quartz tube, and the typical quartz tube has an inner diameter of 76 mm, an outer diameter of 80 mm, and a total length of 150 cm. In the axial direction from the inlet to the outlet of the tubular furnace, the length ratio of the three temperature zones is 1 - 2:1:1. This temperature zone setting and tubular furnace structure design are conducive to precise temperature control in different areas, providing a suitable temperature environment for the dehydration reaction and pyrolysis oxidation reaction of the atomized droplets of the metal salt solution. For example, in the first temperature zone (temperature of 300-400℃), the atomized droplets mainly undergo a preliminary dehydration process to remove water from the solution; in the second temperature zone (temperature of 700-800℃), the metal salt begins to undergo pyrolysis reaction and decomposes into metal oxides or other intermediates; the third temperature zone (temperature of 800-1000℃) further promotes the pyrolysis reaction, making the product more stable and pure. At the same time, the total time for the atomized droplets to pass through the tube furnace is 10-60s. By reasonably controlling the residence time of the droplets in the tube furnace and the temperature of each temperature zone, the particle size, crystal form and other physical and chemical properties of the metal powder can be accurately controlled.

[0051] See also Figure 5 In (a), the product collection system 3 includes a physical separation device 31 and an electrostatic-magnetic field cooperative adsorption device; the physical separation device 31 is provided with at least an inlet 311 and an outlet 312, the inlet 311 serves as the inlet of the product collection system 3, and the outlet 312 is connected to the inlet of the electrostatic-magnetic field cooperative adsorption device; the gas outlet of the electrostatic-magnetic field cooperative adsorption device is connected to the gas inlet of the exhaust gas treatment system;

[0052] In one embodiment, the physical separation device 31 is a cyclone separator, which, in addition to the inlet 311 and the outlet 312, is also provided with an exhaust gas outlet 313, which is connected to the air inlet of the exhaust gas treatment system;

[0053] The inner cavity of the cyclone separator adopts an inverted cone structure with a large opening diameter and a small outlet diameter, the cone angle is 30-45°, and the inner cavity height is 10-15 cm. This structural design utilizes the flow characteristics of the airflow inside the cone. When the airflow containing metal powder enters the physical separation device 31, the cross-sectional area of ​​the cone structure gradually changes, the airflow velocity changes, and the metal powder is separated from the airflow under the action of inertia and gravity. The larger particles of powder first settle to the bottom of the cone, achieving preliminary separation and collection, reducing the workload of the subsequent electrostatic-magnetic field cooperative adsorption device, and improving the overall collection efficiency.

[0054] See also Figure 5In (b), the electrostatic-magnetic field coordinated adsorption device includes an electrostatic collection device 32, and a magnetic field adsorption device 33 arranged outside the electrostatic collection device 32; the electrostatic collection device 32 includes a positive electric field arrangement mechanism 321 and a negative electric field arrangement mechanism 322; in the electrostatic-magnetic field coordinated adsorption device, an electric field is formed between the positive electric field arrangement mechanism 321 and the negative electric field arrangement mechanism 322 of the electrostatic collection device 32. When the airflow containing micro-nano metal powder passes through, the micro-nano metal powder is polarized under the action of the electric field, generates induced charges, and moves toward the electrode under the action of the electric field force to achieve electrostatic adsorption. At the same time, the magnetic field adsorption device 33 arranged outside generates a magnetic field. For magnetic micro-nano metal powder (such as powder containing magnetic elements such as iron), the magnetic field force will make it further gather in the direction of the magnetic field, thereby enhancing the adsorption effect. Through the synergistic effect of electrostatic adsorption and magnetic field adsorption, the collection efficiency of micro-nano metal powder is greatly improved, and the problem that nano- and micro-level fine powders are easy to leak and difficult to collect is effectively solved.

[0055] The negative electrode electric field arrangement mechanism 322 adopts a cylindrical structure, and its inner diameter can be preferably 15-40 cm. The positive electrode electric field arrangement mechanism 321 is arranged inside the cylindrical inner cavity of the negative electrode electric field arrangement mechanism 322, and there is a certain distance between the two.

[0056] In one preferred embodiment, the positive electrode electric field arrangement mechanism 321 includes a trunk 3211 and N positive electrode sheets 3212 axially distributed along the trunk 3211; the trunk 3211 is axially distributed from the inlet of the electrostatic collection device 32 to the gas outlet. In the axial direction from the inlet of the electrostatic collection device 32 to the gas outlet, the size of the n1 positive electrode sheets 3212 located on the trunk 3211 near the inlet of the electrostatic collection device 32 gradually increases, and n1≥1; this structural design enables the larger positive electrode sheets 3212 at the airflow inlet to provide a larger electric field range, generate a stronger adsorption force on the initially entering micro-nano metal powder, and effectively capture larger particles or powders in high concentration areas. As the airflow flows toward the outlet, the smaller positive electrode sheets 3212 continue to adsorb the remaining unadsorbed powder in the subsequent area, ensuring that the powders at different positions in the entire collection process can be effectively collected, thereby improving the comprehensiveness and thoroughness of the collection. The n2 positive electrode sheets 3212 located on the trunk 3211 near the inlet of the electrostatic collection device 32 have the same size, n2≥1, n2=N-n1; this structure provides a stable and uniform electric field strength in a certain area, ensuring that the micro-nano metal powder in the area is subjected to a relatively stable electric field force, which helps to stably adsorb powders within a specific particle size range or concentration range, avoiding the escape of some powders or uneven adsorption due to changes in the electric field strength, and further improving the stability and accuracy of the collection.

[0057] In addition, the positive electrode electric field arrangement mechanism 321 may also adopt other structural designs, such as Figure 8 Middle (a), Figure 8 Middle (b).

[0058] In the positive electrode electric field arrangement mechanism 321 , in the axial direction from the inlet of the static electricity collection device 32 to the gas outlet, the sizes of the n1 positive electrode sheets 3212 close to the inlet gradually increase.

[0059] Specifically, the positive electrode sheet 3212 is a circular sheet with a sawtooth structure at the edge. The sawtooth structure increases the electric field intensity gradient at the edge of the electrode sheet, so that the micro-nano metal powder is subjected to a greater change in the electric field force when passing through the edge of the electrode sheet, and is more easily adsorbed onto the electrode sheet. At the same time, the sawtooth structure can also change the flow state of the airflow around the electrode sheet, causing the airflow to generate local turbulence, increasing the chance of the micro-nano metal powder contacting the electrode sheet, thereby improving the adsorption efficiency.

[0060] More specifically, the positive electrode sheet 3212 has a disc diameter of 3-30 cm, a length of the edge serrations of 5-20 mm, and an angle of the serrations of 15-120°.

[0061] Specifically, the n1 positive electrode sheets 3212 located on the trunk 3211 close to the inlet of the electrostatic collection device 32 are in a cone structure with a cone angle of 30-60°.

[0062] The magnetic field adsorption device 33 is arranged outside the electrostatic collection device 32, and its magnetic field strength is 0.01 - 0.2 T. For micro-nano metal powders containing magnetic elements (such as iron, cobalt, nickel, etc.), the magnetic field force generated by the magnetic field adsorption device 33 and the electric field force generated by electrostatic adsorption work together to make the metal powder more efficiently adsorbed and collected, further improve the collection rate, and help maintain the dispersion and uniformity of the powder.

[0063] Specifically, the materials of other devices connected to the positive electric field arrangement mechanism 321 and the negative electric field arrangement mechanism 322 are all made of acid-resistant, alkali-resistant and corrosion-resistant materials. The support parts used for the collection end and the charge generation end of the electrostatic collection device 32 are all made of high-voltage resistant insulating materials.

[0064] Through the special structural design of the positive electrode electric field arrangement mechanism 321, combined with the electrostatic-magnetic field synergistic adsorption, not only the collection rate of micro-nano metal powders is improved, but also the collected powders are made purer and the mixing of impurities is reduced. This synergistic effect and special structural design also play a positive role in solving the problem of micro-nano metal powder agglomeration and improving the uniformity of powders, because the uniform and stable adsorption process helps to maintain the dispersed state of the powders and avoid local agglomeration caused by uneven adsorption during the collection process, thereby improving the overall quality of the product, and facilitating the large-scale production of micro-nano metal powders with high uniformity and high dispersion, which has significant advantages in the application of battery materials, catalysts and magnetic materials.

[0065] In one preferred embodiment, the continuous automated production device for metal micro-nano powders also includes a gas stabilizer; the gas stabilizer is used to control the flow rate of the carrier gas in the solution loading container 11, for example, 5-25 L / min. Preferably, the carrier gas is a mixture of argon and hydrogen; more preferably, the volume ratio of Ar to H2 is 9:1. The gas stabilizer ensures that the carrier gas enters the solution loading container 11 at a stable flow rate, and stably brings the atomized droplets into the high-temperature pyrolysis system 2. Argon, as an inert gas, plays a protective role to prevent metal powders from oxidizing at high temperatures; hydrogen may participate in the reduction reaction during the pyrolysis process, affecting the chemical composition and properties of the metal powder. By accurately controlling the ratio and flow rate of the two, the pyrolysis reaction process can be optimized and the product quality can be improved.

[0066] One preferred embodiment is shown in Figure 6 The exhaust gas treatment system is provided with a catalyst, and the catalyst includes at least one of a platinum-palladium catalyst, an SCR catalyst, a vanadium-titanium catalyst, a copper-based catalyst, an iron-based catalyst, a cerium-zirconium catalyst, and a manganese oxide catalyst. When the exhaust gas generated during the production process enters the exhaust gas treatment system, under the action of the catalyst, the toxic and harmful components (such as nitrogen oxides, sulfur oxides, etc.) in the exhaust gas undergo a chemical reaction and are converted into harmless nitrogen, water and other substances before being discharged, which effectively solves the environmental protection and production safety issues, ensures that the entire production process complies with environmental protection regulations, and reduces pollution to the environment.

[0067] The present invention realizes the continuous automated production of micro-nano metal powders through the coordinated work of various parts, forming a complete, efficient and environmentally friendly process flow from raw material atomization to product collection and tail gas treatment, effectively solving many problems existing in traditional preparation methods and providing a feasible solution for the large-scale production of micro-nano metal powders.

[0068] At least one embodiment further provides a method for continuous automated production of micro-nano metal powders, specifically:

[0069] Atomizing the metal salt solution to a micron or submicron level to obtain atomized droplets;

[0070] The atomized droplets are brought into a preheated tubular furnace by a carrier gas to cause dehydration reaction and pyrolysis oxidation reaction; wherein the three temperature zones of the tubular furnace are 300-400°C, 700-800°C, and 800-1000°C respectively;

[0071] The products of the tubular furnace are collected through physical separation, electrostatic adsorption and magnetic field adsorption to obtain the precursor powder of the magnetic material, and the tail gas is discharged after being treated by the tail gas treatment system.

[0072] Preferably, the metal in the metal salt is at least one of lithium, beryllium, sodium, magnesium, aluminum, potassium, calcium, scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, gallium, silver, cadmium, indium, tin and lanthanum elements;

[0073] Preferably, the metal salt is one or more of nitrate, acetate, phosphate and chloride.

[0074] It should be understood that the contents not described in detail in the above preparation method or the description of the obtained product are common parameters that can be easily thought of by those skilled in the art and can be adjusted by those skilled in the art according to actual conditions, such as temperature, etc., and therefore detailed descriptions thereof can be omitted.

[0075] For the understanding of those skilled in the art, the technical solutions in the embodiments of the present invention are clearly and completely described below in combination with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Example 1

[0076] A continuous automated production method and device for preparing highly uniform and highly dispersed micro-nano metal powders by high-temperature spray pyrolysis, comprising the following steps:

[0077] S1. First prepare a 0.2 mol / L ferric nitrate solution, and then use an ultrasonic sprayer to atomize the solution to a micron or submicron level to obtain atomized droplets;

[0078] S2, using a mixture of argon and hydrogen to bring the atomized droplets into a heated quartz tube, wherein the heating area of ​​the quartz tube is divided into three temperature zones with a length ratio of 2:1:1, the first section is 300°C, the second section is 700°C, and the third section is 800°C. The atomized solution passes through the quartz tube for a total of 30 seconds. Finally, the precursor powder of the magnetic material is collected through the physical separation device 31 and the electrostatic-magnetic field cooperative adsorption device.

[0079] The carrier gas is a mixed gas of Ar and H2, in which Ar accounts for 90% of the total volume, H2 accounts for 10% of the total volume, and the intake volume of the mixed gas of Ar and H2 is 2 L / min.

[0080] In the electrostatic-magnetic field cooperative adsorption device, the voltage of the high-voltage static electricity is selected to be 50 KV, and the magnetic field strength of the magnetic field adsorption device 33 is 0.01-0.2 T. Example 2

[0081] A continuous automated production method and device for preparing highly uniform and highly dispersed micro-nano metal powders by high-temperature spray pyrolysis, comprising the following steps:

[0082] S1. First, ferric nitrate and samarium nitrate are mixed in a molar ratio of 17:2.4, wherein the concentration of the ferric nitrate solution is 0.05 mol / L, and the concentration of the samarium nitrate solution is 0.007 mol / L. Then, an ultrasonic sprayer is used to atomize the mixed solution to a micron or submicron level to obtain atomized droplets;

[0083] S2, using a mixture of argon and hydrogen to bring the atomized droplets into a heated quartz tube, wherein the heating area of ​​the quartz tube is divided into three temperature zones with a length ratio of 2:1:1, the first section is 400°C, the second section is 750°C, and the third section is 900°C. The atomized solution passes through the quartz tube for a total of 30 seconds. Finally, the precursor powder of the magnetic material is collected through a physical separation device 31 and an electrostatic-magnetic field cooperative adsorption device.

[0084] The carrier gas is a mixed gas of Ar and H2, in which Ar accounts for 90% of the total volume, H2 accounts for 10% of the total volume, and the intake volume of the mixed gas of Ar and H2 is 2 L / min.

[0085] In the electrostatic-magnetic field cooperative adsorption device, the voltage of the high-voltage static electricity is selected to be 90 KV, and the magnetic field strength of the magnetic field adsorption device 33 is 0.01-0.2 T. Example 3

[0086] A continuous automated production method and device for preparing highly uniform and highly dispersed micro-nano metal powders by high-temperature spray pyrolysis, comprising the following steps:

[0087] S1. First, ferric nitrate and samarium nitrate are mixed in a molar ratio of 17:2.6, wherein the concentration of the ferric nitrate solution is 0.1 mol / L, and the concentration of the samarium nitrate solution is 0.014 mol / L. Then, an ultrasonic sprayer is used to atomize the mixed solution to a micron or submicron level to obtain atomized droplets.

[0088] S2, using a mixture of argon and hydrogen to bring the atomized droplets into a heated quartz tube, wherein the heating area of ​​the quartz tube is divided into three temperature zones with a length ratio of 2:1:1, the first section is 400°C, the second section is 800°C, and the third section is 900°C. The atomized solution passes through the quartz tube for a total of 45 seconds. Finally, the precursor powder of the magnetic material is collected through the physical separation device 31 and the electrostatic-magnetic field coordinated adsorption device.

[0089] The carrier gas is a mixed gas of Ar and H2, in which Ar accounts for 90% of the total volume, H2 accounts for 10% of the total volume, and the intake volume of the mixed gas of Ar and H2 is 1.5L / min.

[0090] In the electrostatic-magnetic field cooperative adsorption device, the voltage of the high-voltage static electricity is selected to be 90 KV, and the magnetic field strength of the magnetic field adsorption device 33 is 0.01-0.2 T.

[0091] Figure 7 Middle (a) - Figure 7 (b) is the scanning electron microscope characterization of the sample of Example 1. Figure 7 (c) is the scanning electron microscope characterization of the sample in Example 2. Figure 7 (d) is the scanning electron microscope characterization of the sample in Example 3. From these figures, it can be seen that the product obtained by the present invention is nano-scale particles, and has the characteristics of uniform particles, no agglomeration, and good dispersibility.

[0092] Figure 8 It can be seen that the generated micro-nano metal powder can be well collected through physical separation and electrostatic-magnetic field coordinated adsorption collection method.

[0093] from Fig. 9 It can be seen that the XRD spectrum of Example 3 is consistent with the standard PDF card, and the iron-containing multi-metal powder produced by the atmosphere of hydrogen and argon mixture can be better collected under the cooperation of the magnetic field.

[0094] The preparation method and collection method of the present invention have simple processes, are helpful for studying the performance of micro-nano metal powders, have low raw material costs, are simple to operate, solve the problem of agglomeration of micro-nano metal powders, and are easy to mass-produce micro-nano metal powders with high dispersion and uniformity.

[0095] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any equivalent replacement or change made by any technician familiar with the present invention within the technical scope disclosed by the present invention according to the technical solution and the inventive concept of the present invention should be covered by the protection scope of the present invention.

Claims

1. A metal micro-nano powder continuous automated production device, characterized in that: It comprises an ultrasonic atomization system (1), a high-temperature pyrolysis system (2), a product collection system (3) and an exhaust gas treatment system which are connected in sequence; The ultrasonic atomization system (1) comprises a solution loading container (11) and an ultrasonic atomizer (12) located at the bottom of the solution loading container (11); wherein the solution loading container (11) comprises a container body (111) and a plurality of high sound-transmitting membranes (112) arranged at the bottom of the container body (111); the high sound-transmitting membranes (112) face the ultrasonic atomizer (12); The inlet of the solution loading container (11) is connected to the metal salt dissolving conveying device, and the outlet is connected to the inlet of the high temperature pyrolysis system (2); The high-temperature pyrolysis system (2) adopts a tubular furnace, which includes three temperature zones with segmented temperature control; the outlet of the high-temperature pyrolysis system (2) is connected to the inlet of the product collection system (3); The product collection system (3) comprises a physical separation device (31) and an electrostatic-magnetic field cooperative adsorption device; the inlet of the physical separation device (31) serves as the inlet of the product collection system (3), and the outlet is connected to the inlet of the electrostatic-magnetic field cooperative adsorption device; the gas outlet of the electrostatic-magnetic field cooperative adsorption device is connected to the gas inlet of the tail gas treatment system; The electrostatic-magnetic field cooperative adsorption device comprises an electrostatic collection device (32) and a magnetic field adsorption device (33) arranged outside the electrostatic collection device (32); The electrostatic collection device (32) comprises a positive pole electric field arrangement mechanism (321) and a negative pole electric field arrangement mechanism (322); the negative pole electric field arrangement mechanism (322) adopts a cylindrical structure; the positive pole electric field arrangement mechanism (321) is arranged inside the cylindrical inner cavity of the negative pole electric field arrangement mechanism (322); and there is a distance between the positive pole electric field arrangement mechanism (321) and the negative pole electric field arrangement mechanism (322).

2. The device according to claim 1, characterized in that: The positive electrode electric field arrangement mechanism (321) comprises a trunk (3211) and N positive electrode sheets (3212) distributed axially along the trunk (3211); the trunk (3211) is distributed axially from the inlet of the electrostatic collection device (32) to the gas outlet; in the axial direction from the inlet of the electrostatic collection device (32) to the gas outlet, the size of n1 positive electrode sheets (3212) located on the trunk (3211) close to the inlet of the electrostatic collection device (32) gradually increases; the size of n2 positive electrode sheets (3212) located on the trunk (3211) close to the inlet of the electrostatic collection device (32) is the same; n1≥1, n2≥1, n1+n2=N.

3. The device according to claim 2, characterized in that: The positive electrode sheet (3212) is a circular sheet with a serrated edge.

4. The device according to claim 1, characterized in that: The metal micro-nano powder continuous automated production device also includes a solution control system; the solution control system is used to control the liquid level of the solution in the solution loading container (11).

5. The device according to claim 1 or 4, characterized in that: The metal micro-nano powder continuous automated production device also includes a gas flow stabilizer; the gas flow stabilizer is used to control the flow rate of the carrier gas in the solution loading container (11).

6. The device according to claim 1, characterized in that: The magnetic field strength of the magnetic field adsorption device (33) is 0.01-0.2 T, and the voltage of the electrostatic collection device (32) is 20-120 KV.

7. The device according to claim 1, characterized in that: The tail gas treatment system is provided with a catalyst, and the catalyst includes at least one of a platinum-palladium catalyst, an SCR catalyst, a vanadium-titanium catalyst, a copper-based catalyst, an iron-based catalyst, a cerium-zirconium catalyst and a manganese oxide catalyst.

8. The device according to claim 1, characterized in that: In the axial direction from the inlet to the outlet of the tube furnace, the length ratio of the three temperature zones is 1-2:1:

1.

9. A method for continuous automated production of micro-nano metal powders based on the device according to any one of claims 1 to 8, characterized in that: The method comprises: Atomizing the metal salt solution to a micron or submicron level to obtain atomized droplets; The atomized droplets are brought into a preheated tubular furnace by a carrier gas to cause dehydration reaction and pyrolysis oxidation reaction; wherein the three temperature zones of the tubular furnace are 300-400°C, 700-800°C, and 800-1000°C respectively; The products of the tubular furnace are collected through physical separation, electrostatic adsorption and magnetic field adsorption to obtain the precursor powder of the magnetic material, and the tail gas is discharged after being treated by the tail gas treatment system.

10. The method according to claim 9, characterized in that: The metal in the metal salt is at least one of lithium, beryllium, sodium, magnesium, aluminum, potassium, calcium, scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, gallium, silver, cadmium, indium, tin and lanthanum elements.

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