Micro-nano powder washing and separating device and method

Abstract

The invention discloses a micro-nano powder washing and separating device and method, and relates to the technical field of washing and separating of micro-nano powder.The device comprises an outer barrel, a centrifugal barrel and a cover, a plurality of through holes I are formed in the barrel wall of the centrifugal barrel, filter cloth is installed next to the inner wall of the centrifugal barrel, and a discharging opening is formed in the center of the bottom of the centrifugal barrel; the centrifugal barrel is connected with a driving motor I through a transmission assembly, the driving motor I drives the centrifugal barrel to rotate, a liquid outlet is formed in the bottom of the outer barrel, the cover body is detachably connected with the outer barrel, a feeding pipe and a high-pressure water / hot air pipe are connected to the cover body, and a plurality of through holes II are formed in the high-pressure water / hot air pipe; the cover body is provided with a stirring paddle and a lifting brush, the stirring paddle is driven by a driving motor II, the driving assembly drives the lifting brush to move, and the problems that in the prior art, a common industrial centrifugal machine is not suitable for washing micro-nano powder, and the functions of repeated soaking and cleaning, automatic stirring and dispersing, automatic filter cloth cleaning and the like are difficult to achieve are solved; the washing efficiency is not high, and the powder purity is not ideal.

Description

Technical Field

[0001] The present invention relates to the technical field of washing and separation of micro-nano powders, and in particular to a device and method for washing and separating micro-nano powders. Background Art

[0002] Micro-nano powder materials mainly refer to materials with particle sizes in the micron and nanometer levels, and are commonly found in spherical or ellipsoidal particles with particle sizes between 100nm and 100μm. Because micro-nano particles have a special small size effect and high surface energy, they exhibit special properties in optics, thermal conductivity, electrical conductivity, metallization, magnetism, etc. Common micro-nano powder materials are mainly used in the following aspects: semiconductor electronic information industry, such as ultrafine metal powders for conductive slurries, ultrafine silver powders, ultrafine copper powders, ultrafine nickel powders, ultrafine aluminum powders, ultrafine tungsten powders, ultrafine platinum powders, etc.; electrode materials such as lithium nickel cobalt oxide, lithium carbonate, and carbon powder used in new energy batteries; various types of coating ceramic powders such as titanium dioxide, zinc oxide, silicon powder, zirconium oxide, and silicon carbide used in chemical ceramics and new energy; calcium carbonate, starch, glucose, ascorbic acid, food additives, etc. used in food and medicine; wollastonite powder, silicate powder, and refractory powders used in construction and other industries.

[0003] The preparation process of most of the above powders involves wet chemical preparation or requires washing, filtering and drying. Micro-nano powder particles are small, and the particles will spontaneously agglomerate or even form blocks. If the particles agglomerate severely, the original performance advantages of micro-nano powders will be reduced. In the application fields of new chemical materials, new energy, semiconductors, etc., powders are required to have high purity and dispersibility. To improve the purity of powders, a sophisticated washing process is required. The dispersibility and purity of ultrafine powders prepared by wet chemical methods are mutually restrictive and contradictory, which brings great difficulties to engineering technology. Except for salt particles that are crystallized, most powders are insoluble in solvents such as water, or have slow solubility. In theory, impurities can be removed by washing using this characteristic. With the rapid development of my country's industry, science and technology, the demand for various ultrafine powders, especially metal powders, ceramic powders, coatings, etc., has increased sharply. Solving the purity and dispersibility of powders under large-scale is a challenge facing current engineering technology.

[0004] At present, conventional washing and filtering equipment and technology can meet the requirements of particle filtering and washing of several hundred microns or more, but they can no longer meet the requirements of industrial refinement for micron-level, nano-level and special performance powders. The washing and filtering processing capacity, washing efficiency, dispersion effect, product rate, etc. of powders are restricted by equipment and process technology. For example, in the semiconductor industry, micro-nano-level ultrafine silver powder has excellent electrical and thermal conductivity, metal stability, and weldability, making it an important electrode packaging material. Ultrafine silver powder is prepared by wet chemical oxidation-reduction. The silver powder particle size is between 50nm and 1500nm, and the specific surface area is between 0.5 and 12m 2 / g, silver powder has small particle size, high specific surface area and high packing density.

[0005] In order to ensure that the silver powder has good dispersibility, a large amount of dispersants, surfactants, etc. are generally added during the synthesis stage. At the same time, in order to increase the specific surface area of ​​the silver powder particles, the surface of the silver particles is often made rough, resulting in the silver powder adsorbing a large amount of organic matter, salts and other harmful ions. These impurities will seriously affect the application performance of the silver powder in the product, and the silver powder needs to be washed and filtered to remove impurities. However, in the process of removing these impurities, the particles often reunite. The existing washing method usually pours the synthesized silver powder into the filter kettle, removes the solvent by positive pressure or negative pressure, and then repeatedly injects a certain amount of pure water, and filters after manual stirring. When washing the silver powder in this way, the silver powder particles are easy to block the filter holes, and it is impossible to scale up, which affects the final water content, purity, dispersibility, yield rate and processing efficiency of the silver powder. With the emergence of industrial-grade centrifuges, the difficulties of washing and filtering some powders have been solved, but for the cleaning of metal powders, ceramic powders and other powders with high added value, there are still bottlenecks in the process technology of filtering and dispersion.

[0006] Industrial centrifuges have a high centrifugal force separation coefficient and are good at separating large-particle powder materials, especially for sewage treatment, food processing wastewater treatment, etc., without considering the damage of centrifugal force to the powder. However, for metal and ceramic powders, due to their finer particles, less protective layer on the particle surface, and higher specific gravity, small particles tend to pass through the filter and flow out under the action of the centrifuge, and the filter cake is easy to agglomerate and compact under the action of centrifugal force. Once agglomerated and compacted, it is difficult to disperse, and eventually the performance of the powder itself is damaged. It can be seen that the commonly used industrial centrifuges in the prior art are not suitable for washing micro-nano powders, and it is difficult to achieve functions such as multiple immersion cleaning, automatic stirring and dispersion, automatic cleaning of filter cloth, and automatic discharge. Summary of the invention

[0007] The purpose of the present invention is to solve the problem that the commonly used industrial centrifuges in the prior art are not suitable for washing micro-nano powders, and it is difficult to achieve functions such as multiple immersion cleaning, automatic stirring and dispersing, and automatic cleaning of filter cloths. The present invention proposes a micro-nano powder washing and separation device and method, which can achieve efficient washing and can realize the functions of automatic stirring, dispersing, and automatic cleaning of filter cloths, drying filter cloths, and centrifugal barrels.

[0008] The present invention is achieved through the following technical solutions: The micro-nano powder washing and separation device comprises an outer barrel, a centrifugal barrel and a cover body. A plurality of through holes I are opened on the barrel wall of the centrifugal barrel. A filter cloth is installed close to the inner wall of the centrifugal barrel. The bottom of the centrifugal barrel is a smooth arc bottom surface. A discharge port is arranged at the center of the bottom of the centrifugal barrel. The bottom of the centrifugal barrel is connected to a drive motor I through a transmission assembly passing through the outer barrel. The drive motor I drives the centrifugal barrel to rotate. A liquid discharge port is arranged at the bottom of the outer barrel. The cover body is detachably connected to the outer barrel, and is connected to a feed pipe and a high-pressure water / hot air pipe. The high-pressure water / hot air pipe is provided with a plurality of through holes Ⅱ, and the through holes Ⅱ face the filter cloth. The cover body is provided with a stirring paddle that can move up and down and a lifting brush for brushing the wall of the centrifugal barrel. The stirring paddle is driven by a driving motor Ⅱ, and the lifting brush is driven by a driving assembly to reciprocate in the longitudinal direction of the centrifugal barrel and rotate in the horizontal direction.

[0009] Furthermore, the high-pressure water / hot air pipe extends into the lower part of the centrifugal barrel, with the through hole II at the upper part facing upward; the through hole II at the lower part facing downward, and the water or hot air sprayed out by the high-pressure water / hot air pipe covers the filter cloth in the longitudinal direction of the centrifugal barrel wall.

[0010] Furthermore, the aperture of the through hole II is about 0.5-1.0 mm.

[0011] Furthermore, the stirring paddle includes a detachable stirring rod and a stirring head. The stirring paddle includes two stirring paddles, which are symmetrically arranged on the cover body; the stirring head is made of a rubber strip, a silicone strip or a polytetrafluoro strip material.

[0012] Furthermore, a backwashing spray head is provided on the cover body, and a sight glass is also installed on the cover body.

[0013] Furthermore, the filtering accuracy of the filter cloth is 0.1-2000 μm, and the filter cloth is made of polypropylene, polyester or polytetrafluoroethylene.

[0014] Furthermore, the roughness of the inner wall and bottom surface of the centrifugal bucket is less than 1Ra, and the angle between the bottom of the centrifugal bucket and the horizontal plane is 10°~30°.

[0015] A method for using the micro-nano powder washing and separation device as described in any of the above items comprises the following steps: S1. Select a filter cloth with a matching filtration accuracy according to the micro-nano powder to be washed, and then place the filter cloth flat on the inner wall of the centrifuge barrel. After the stirring paddle is lowered to a certain height, close the discharge port, close the cover, and open the valve and discharge port on the feed pipe; S2. Slowly pump the wet powder material to be washed from the feed pipe, and the material filling volume does not exceed 70% of the total capacity of the centrifugal bucket. Start the drive motor I, and the device separates the material. When the discharge speed of the discharge port slows down or stops significantly, stop the drive motor I. S3, open the high-pressure water / hot air pipe, switch to the liquid inlet state, start the drive motor I, and in the low-speed state, wash the wet filter cake attached to the filter cloth through the washing liquid introduced by the high-pressure water / hot air pipe and drop it to the bottom of the centrifugal barrel. After the washing is complete, add the washing liquid through the feed pipe at the same time, and stir, wash, soak and disperse the material several times by controlling the start / stop interval time of the drive motor II; S4, after washing and dispersing is completed, the driving motor II is stopped, and the driving motor I is started to perform solid-liquid separation again. When the discharge speed of the discharge port is obviously slowed down or stopped, the driving motor I is stopped; S5, repeat steps S3 and S4 until the washed material is in a powder state or reaches the washing requirements, then stop washing; S6. After further drying the washing liquid from the powder, open the discharge port, discharge the dried filter cake out of the centrifugal barrel, turn on the drive motor I, start the lifting brush at a low speed to brush all the powder remaining on the filter cloth to the bottom of the barrel and discharge it; S7. Keep the centrifugal barrel running at a low speed, switch the high-pressure water / hot air pipe to the liquid-intake state, and start the lifting brush to clean the filter cloth. After a certain period of time, switch the high-pressure water / hot air pipe to the hot air-intake state and use the hot air to dry the filter cloth.

[0016] Furthermore, when the stirring paddle is working, the end of the stirring paddle is 20 to 50 mm away from the filter cloth.

[0017] Furthermore, when a plurality of stirring paddles are installed on the cover body, each stirring paddle descends to a different height when working.

[0018] Furthermore, the washing liquid is one of pure water, ethanol, a surfactant solution, a mixed solution of pure water and a surfactant, or an ethanol-water solution.

[0019] Furthermore, in step S5, the washing endpoint judgment criteria are: the pH of the filtrate is between 5 and 8, the conductivity is less than 500 μs / cm, and the filter cake has no agglomeration in the solvent.

[0020] Furthermore, in step S6, before starting the lifting brush, the high-pressure water / hot air pipe is switched to the hot air intake state, and hot air is introduced first to dry the powder remaining on the filter cloth.

[0021] Compared with the prior art, the present invention has the following advantages and beneficial effects: 1. In the present invention, a new structure of micro-nano powder washing and separation device is proposed, in which a filter cloth is installed close to the inner wall of the centrifugal barrel, and the filter cloth is only installed at the inner wall of the centrifugal barrel. The bottom of the centrifugal barrel is a smooth arc bottom surface. During centrifugal filtration, the filtrate is only discharged along the inner wall of the centrifugal barrel. At the same time, in this device, closing the drain port and the discharge port can achieve the purpose of soaking and washing the micro-nano powder, and then using the stirring paddle installed on the cover body to achieve the purpose of dispersing the micro-nano powder in the washing liquid. The smooth arc bottom surface can also prevent the micro-nano powder from being deposited at the bottom of the device and the agglomeration of the micro-nano powder. And the filter cloth can select a filter cloth with suitable filtration accuracy according to the specifications of the washed and dispersed particles. The device can achieve soaking and stirring, accelerate the dissolution and separation of impurities adsorbed by the powder, and improve the purity of powder cleaning and batch powder dispersion performance.

[0022] At the same time, the device is provided with a detachable cover, which is also connected to a feed pipe and a high-pressure water / hot air pipe. The high-pressure water / hot air pipe is provided with a plurality of through holes II, which face the filter cloth. When the device is in use, high-pressure water can be introduced through the high-pressure water / hot air pipe to wash the filter cloth to prevent the micro-nano powder from agglomerating and agglomerating near the filter cloth, which affects the product quality; or hot air (or hot steam) can be introduced into the high-pressure water / hot air pipe to purge the micro-nano powder attached to the filter cloth or dry the micro-nano powder, or clean and dry the device after use for the next use. Such a structure can realize deep cleaning and automatic cleaning of the residual powder on the filter cloth, greatly saving the time of replacing and cleaning the filter bag during mass production, and improving the product rate at the same time.

[0023] Second, in the present invention, a more optimal structure is proposed, the high-pressure water / hot air pipe extends into the lower part of the centrifugal barrel, the through hole II on the upper part of the high-pressure water / hot air pipe faces upward; the through hole II on the lower part faces downward, and the water or hot air sprayed by the high-pressure water / hot air pipe covers the filter cloth in the longitudinal direction of the centrifugal barrel wall, ensuring that the water or hot air sprayed by the high-pressure water / hot air pipe covers the filter cloth in the longitudinal direction of the centrifugal barrel wall, achieving a better washing and drying effect. After many tests, the aperture of through hole II is set to 0.5~1.0mm, which can meet the washing and drying needs of most micro-nano powders.

[0024] 3. In the present invention, a more optimal structure is proposed, in which the stirring paddle includes a detachable stirring rod and a stirring head. The stirring blade material of the stirring head can be selected from materials with different hardness and stiffness such as rubber strips, silicone strips, polytetrafluoro strips, etc. according to the needs. In actual application, micro-nano powder washing, dispersion and filtration devices of different specifications can be designed according to the material processing capacity, and then the appropriate number of stirring paddles can be selected and designed according to the specifications of the device. The stirring paddle is preferably designed to be two, and the two stirring paddles are symmetrically arranged on the cover body. When in use, the stirring heads of the two stirring paddles are lowered to different heights, which is convenient for quickly and fully stirring the material.

[0025] 4. In the present invention, a sight glass is also installed on the cover body to facilitate observation of the status of materials and mechanisms in the device. A backwash spray head is provided on the cover body, and the backwash spray head is connected to a pure water supply pipe to achieve self-cleaning of the machine cover and the sight glass, meeting green environmental protection requirements. The backwash spray head can also absorb volatile solvents and dust.

[0026] 5. In the present invention, the filtration accuracy of the filter cloth is 0.1~2000μm, which can meet the needs of washing and filtering most powders. The filter cloth is made of polypropylene, polyester or polytetrafluoroethylene according to the properties of the material (such as viscosity, solid content, particle size, etc.). The filter cloth is detachably connected and installed with the centrifugal barrel.

[0027] 6. In the present invention, the inner wall of the centrifugal barrel needs to be polished, the roughness of the inner wall and the bottom of the centrifugal barrel is less than 1Ra, the angle between the bottom of the centrifugal barrel and the horizontal plane is 10°~30°, to ensure that the material at the bottom slides down to the filter cloth at the barrel wall under centrifugal force, the lowest end of the center of the barrel bottom is designed to be a horizontal plane, and is smoothly connected with the arc chamfer of the side wall of the centrifugal barrel to prevent material accumulation.

[0028] 7. In the present invention, a method for using the aforementioned micro-nano powder washing and separation device is proposed. Through this method, the micro-nano powder is soaked and washed (determining whether soaking is required is determined based on the size and other structural characteristics of the micro-nano powder), which solves the problem of powder agglomeration and agglomeration that is prone to occur after multiple centrifugation using traditional powder washing methods. There is no need for manual stirring, which improves the degree of automation and achieves sufficient stirring and dispersion of ultrafine powders.

[0029] 8. In the present invention, when the stirring paddle is working, the end of the stirring paddle is 20-50 mm away from the filter cloth, so as to achieve a better washing effect while avoiding direct contact between the end of the stirring paddle (stirring blade) and the filter cloth.

[0030] 9. In the present invention, when a plurality of stirring paddles are installed on the cover body, each stirring paddle descends to a different height during operation, thereby improving stirring efficiency.

[0031] 10. In the present invention, in step S5, after multiple tests, analyses and verifications, it is determined that: the washing endpoint judgment standard is set as the filtrate pH is 5-8, the conductivity is less than 500μs / cm, and the filter cake has no agglomeration in the solvent. After the endpoint judgment standard is determined, it is convenient to realize automated production and large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a three-dimensional structural schematic diagram of an embodiment of a micro-nano powder washing, dispersing and filtering device.

[0033] Figure 2 yes Figure 1 Front view of .

[0034] Figure 3 yes Figure 1 Top view of the .

[0035] Figure 4 yes Figure 3 AA section view.

[0036] Figure 5 yes Figure 4 Enlarged view of part A.

[0037] Figure 6 This is a partial enlarged view of the high-pressure water / hot air pipe.

[0038] Figure 7 It is a structural schematic diagram of an implementation method of a filter cloth quick-install assembly.

[0039] Among them, 1. outer barrel; 2. centrifugal barrel; 3. through hole I; 4. filter cloth; 5. transmission assembly; 6. drive motor I; 7. discharge port; 8. drain port; 9. cover body; 10. feed pipe; 11. high-pressure water / hot air pipe; 12. through hole II; 13. stirring paddle; 14. lifting brush; 15. drive motor II; 16. drive assembly; 17. backwashing spray head; 18. sight glass; 19. support seat; 20. locking piece; 21. filter cloth quick-release assembly; 13.1. stirring rod; 13.2. stirring head; 14.1. brush head; 14.2. connecting rod; 21.1. quick-release bolt; 21.2. bottom ring; 21.3. liquid blocking plate. DETAILED DESCRIPTION

[0040] The present invention is further described in detail below in conjunction with examples, but the embodiments of the present invention are not limited thereto.

[0041] Example 1 This embodiment is a basic implementation method. Figures 1 to 5 The micro-nano powder washing and separation device comprises an outer barrel 1, a centrifugal barrel 2 and a cover body 9. A plurality of through holes Ⅰ3 are opened on the barrel wall of the centrifugal barrel 2. A filter cloth 4 is installed close to the inner wall of the centrifugal barrel 2. The bottom of the centrifugal barrel 2 is a smooth arc-shaped bottom surface. A discharge port 7 is arranged at the center of the bottom of the centrifugal barrel 2. The bottom of the centrifugal barrel 2 is connected to a drive motor Ⅰ6 through a transmission assembly 5 passing through the outer barrel 1. The drive motor Ⅰ6 drives the centrifugal barrel 2 to rotate. A discharge port 8 is arranged at the bottom of the outer barrel 1.

[0042] The cover body 9 is detachably connected to the outer barrel 1, and a feed pipe 10 and a high-pressure water / hot air pipe 11 are connected to the cover body 9. The high-pressure water / hot air pipe 11 is provided with a plurality of through holes Ⅱ12, and the through holes Ⅱ12 face the filter cloth 4. A stirring paddle 13 that can move up and down and a lifting brush 14 for brushing the barrel wall of the centrifugal barrel 2 are installed on the cover body 9. The stirring paddle 13 is driven by a driving motor Ⅱ15, and the lifting brush 14 is driven by a driving assembly 16 to reciprocate in the longitudinal direction of the centrifugal barrel 2 and rotate in the horizontal direction.

[0043] The method for using the micro-nano powder washing and separation device comprises the following steps: S1. Select a filter cloth 4 with a matching filtration accuracy according to the micro-nano powder to be washed, and then place the filter cloth 4 flat on the inner wall of the centrifugal barrel 2. After the stirring paddle 13 is lowered to a certain height, close the discharge port 7, close the cover 9, and open the valve and the discharge port 8 on the feed pipe 10; S2, pump the powder material to be washed into the feed pipe 10, start the drive motor I6, and the device separates the material. When the discharge speed of the discharge port 8 is significantly slowed down or stopped, stop the drive motor I6; S3, open the high-pressure water / hot air pipe 11, switch to the liquid inlet state, start the drive motor I6, and in the low-speed state, the washing liquid introduced by the high-pressure water / hot air pipe 11 washes the wet filter cake attached to the filter cloth 4 to the bottom of the centrifugal barrel 2. After the washing is complete, the washing liquid is added through the feed pipe 10 at the same time, and the material is stirred, washed, soaked and dispersed several times by controlling the start / stop interval time of the drive motor II15; S4, after washing and dispersing is completed, the driving motor II 15 is stopped, and the driving motor I 6 is started to perform solid-liquid separation again. When the discharge speed of the liquid discharge port 8 is significantly slowed down or stopped, the driving motor I 6 is stopped; S5, repeat steps S3 and S4 until the washed material is in a powder state or reaches the washing requirements, then stop washing; S6, after further drying the washing liquid from the powder, open the discharge port 7, discharge the dried filter cake out of the centrifugal barrel 2, turn on the drive motor I6, start the lifting brush 14 at a low speed to brush all the powder remaining on the filter cloth 4 to the bottom of the barrel and discharge it; S7, keep the centrifugal barrel 2 running at a low speed, switch the high-pressure water / hot air pipe 11 to the liquid inlet state, and start the lifting brush 14 to clean the filter cloth 4. After a certain period of time, switch the high-pressure water / hot air pipe 11 to the hot air inlet state, and use the hot air to dry the filter cloth 4.

[0044] Example 2 This embodiment is a further optimization of the embodiment 1, the difference is that the high pressure water / hot air pipe 11 extends into the lower part of the centrifugal barrel 2, refer to Figure 6The through hole II12 at the upper part of the high-pressure water / hot air pipe 11 faces upward; the through hole II12 at the lower part faces downward, and the water or hot air sprayed from the high-pressure water / hot air pipe 11 covers the filter cloth 4 on the longitudinal direction of the barrel wall of the centrifugal barrel 2.

[0045] Example 3 Compared with Example 2, the present embodiment differs in that the aperture of the through hole II 12 is about 0.5-1.0 mm, the high-pressure water / hot air pipe 11 can be designed as a detachable structure according to demand, and the high-pressure water / hot air pipe 11 with a suitable aperture can be replaced according to the specifications of washing and separating micro-nano powders.

[0046] Example 4 The present embodiment is different from the embodiments 1-3 in that the stirring paddle 13 comprises a detachable stirring rod 13.1 and a stirring head 13.2, and the stirring paddle 13 comprises two stirring rods 13.1 and 13.2. Figure 4 The two stirring paddles 13 are symmetrically arranged on the cover body 9. The two stirring paddles 13 can be lowered to different heights during operation to fully stir and disperse the materials in the centrifugal barrel 2. The stirring head 13.2 can be made of rubber strips, silicone strips or polytetrafluoro strips according to the properties of the micro-nano powders.

[0047] Example 5 The difference between this embodiment and the embodiments 1-4 is that the cover 9 is provided with a backwashing spray head 17. Figure 4 A viewing mirror 18 is also installed on the cover body 9.

[0048] Example 6 The present embodiment is different from the embodiments 1-5 in that the filtering accuracy of the filter cloth 4 is 0.1-2000 μm, and the filter cloth 4 is made of polypropylene, polyester or polytetrafluoroethylene.

[0049] Example 7 Compared with Embodiments 1-6, the present embodiment is different in that the roughness of the inner wall and the bottom surface of the centrifugal bucket 2 is less than 1Ra, and the angle between the bottom of the centrifugal bucket 2 and the horizontal plane is 10° to 30°.

[0050] Example 8 The present embodiment is different from Embodiments 1-7 in that when the stirring paddle 13 is working, the end of the stirring paddle 13 is 20-50 mm away from the filter cloth 4 .

[0051] Example 9 The present embodiment is different from the embodiments 1 to 8 in that when a plurality of stirring paddles 13 are installed on the cover 9 , each stirring paddle 13 descends to a different height when in operation.

[0052] Example 10 The present embodiment is different from Embodiments 1-9 in that the washing liquid is one of pure water, ethanol, surfactant solution, a mixed solution of pure water and surfactant, or ethanol-water solution.

[0053] Embodiment 11 The present embodiment is different from Embodiments 1-10 in that, in step S5, the washing endpoint judgment criteria are: the pH of the filtrate is between 5 and 8, the conductivity is less than 500 μs / cm, and the filter cake has no agglomeration in the solvent.

[0054] Example 12 The present embodiment is different from the embodiments 1-11 in that, in step S6, before starting the lifting brush 14, the high-pressure water / hot air pipe 11 is first switched to the hot air intake state, and hot air is first introduced to dry the powder remaining on the filter cloth 4.

[0055] Embodiment 13 In order to facilitate the public to understand the present solution, this embodiment takes a micro-nano powder washing and separation device with a better structure as an example to further illustrate the present solution.

[0056] refer to Figures 1 to 6 The micro-nano powder washing and separation device comprises an outer barrel 1, a centrifugal barrel 2 and a cover body 9. A plurality of through holes Ⅰ3 are provided on the barrel wall of the centrifugal barrel 2. A filter cloth 4 is installed close to the inner wall of the centrifugal barrel 2. The bottom of the centrifugal barrel 2 is a smooth arc-shaped bottom surface. A discharge port 7 is provided at the center of the bottom of the centrifugal barrel 2. The bottom of the centrifugal barrel 2 is connected to a drive motor Ⅰ6 through a transmission assembly 5 passing through the outer barrel 1. The drive motor Ⅰ6 drives the centrifugal barrel 2 to rotate. A discharge port 8 is provided at the bottom of the outer barrel 1. The cover body 9 is detachably connected to the outer barrel 1. A feed pipe 10 and a high-pressure water / hot air pipe 11 are connected to the cover body 9. A plurality of through holes Ⅱ12 are provided on the high-pressure water / hot air pipe 11. The through holes Ⅱ12 face the filter cloth 4. A stirring paddle 13 that can move up and down and a lifting brush 14 for brushing the barrel wall of the centrifugal barrel 2 are installed on the cover body 9. The stirring paddle 13 is driven by a drive motor Ⅱ15. The lifting brush 14 is driven by a drive assembly 16 to reciprocate in the longitudinal direction of the centrifugal barrel 2 and rotate in the horizontal direction.

[0057] In this embodiment, the centrifugal barrel 2 is made of corrosion-resistant stainless steel. Through holes Ⅰ3 are evenly opened at intervals of 10 mm on the side wall of the centrifugal barrel 2 for discharging the liquid passing through the filter cloth 4. The through holes Ⅰ3 are circular holes with a diameter of 10 mm. In particular, the filter cloth 4 is cylindrical and inserted into the side wall of the centrifugal barrel 2, and is flatly attached to the inner wall of the centrifugal barrel 2 through a quick-fit fastening assembly. Filter cloths 4 of different materials and pores are selected according to the viscosity, particle size and other properties of the powder to be washed and filtered. Filter cloth quick-fit assembly 21 Reference Figure 7 , including a bottom ring 21.2, a liquid blocking plate 21.3 and a quick-release bolt 21.1.

[0058] In this embodiment, reference Figure 1The outer barrel 1 and the cover body 9 are opened and closed by a plurality of locking members 20. Of course, the cover body 9 can also be connected to the outer barrel 1 through a hinge on one side, preferably a hydraulic flap mechanism can be set to realize a 0-120° automatic flap structure.

[0059] In this embodiment, the high pressure water / hot air pipe 11 extends into the lower part of the centrifugal barrel 2. Figure 6 The through hole II12 at the upper part of the high-pressure water / hot air pipe 11 faces upward, and the through hole II12 at the lower part faces downward, and the water or hot air sprayed from the high-pressure water / hot air pipe 11 covers the filter cloth 4 in the longitudinal direction of the barrel wall of the centrifugal barrel 2. The aperture of the through hole II12 is set to 0.5 mm.

[0060] In this embodiment, the stirring paddle 13 includes a detachable stirring rod 13.1 and a stirring head 13.2. The stirring paddle 13 includes two stirring paddles, which are symmetrically arranged on the cover body 9. The driving motor II 15 can be frequency-controlled. When in use, the active end of the driving motor II 15 drives the stirring head 13.2 to be inserted into the powder for stirring and dispersing. According to the properties of the powder (such as viscosity, bulk density, hardness, batch size, etc.), the stirring head 13.2 can be selectively installed with stirring blades of different materials and sizes to match the properties of the material for optimal immersion, stirring and dispersion of the material.

[0061] In this embodiment, the lifting brush 14 includes a brush head 14.1 and a connecting rod 14.2 connected to the brush head 14.1. The brush head 14.1 can be rotated 0-90 degrees, and the contact degree with the filter cloth 4 can be adjusted. The brush head 14.1 of different materials can also be replaced as needed. When the centrifugal barrel 2 rotates at a low speed, the brush head 14.1 is extended into and contacts the filter cloth 4 to clean the filter cloth 4 and remove the residual filter cake attached thereto.

[0062] In this embodiment, a backwashing spray head 17 is provided on the cover body 9 , and a sight glass 18 is also installed on the cover body 9 .

[0063] In this embodiment, the bottom of the centrifugal bucket 2 is made of corrosion-resistant stainless steel, the roughness of the inner wall and bottom of the centrifugal bucket 2 is less than 1Ra, and the angle between the bottom of the centrifugal bucket 2 and the horizontal plane is 10°~30°. Ensure that the material at the bottom slides down to the filter cloth 4 on the wall of the centrifugal bucket 2 under the centrifugal force, and the lowest end of the center of the bottom of the bucket is designed to be a horizontal plane and smoothly connected with the arc chamfer of the side wall of the centrifugal bucket 2 to prevent material accumulation.

[0064] In this embodiment, when the stirring paddle 13 is working, the distance between the end of the stirring paddle 13 and the filter cloth 4 is about 50 mm.

[0065] A method for washing and separating micro-nano powders. This embodiment takes washing, dispersing and filtering micron-shaped spherical silver powder as an example. The solid content of the silver powder is 50% to 80%, and the nitrate and organic impurities are 5% to 20%. The particle size D10 is 0.5 to 1.5 μm, D50 is 1.5 to 5 μm, and D90 is 3.0 to 7 μm. The bulk density in the wet state is 1.5 to 2.5 g / mL, the pH is 1 to 3, and the conductivity is 40 ms / cm. The present scheme is further illustrated.

[0066] The specific steps include: S1. Select a filter cloth 4 of polypropylene material with a filtration accuracy of 10 μm according to the micro-nano powder to be washed, and then flatten the filter cloth 4 on the inner wall of the centrifugal barrel 2. After the stirring paddle 13 is lowered to a certain height, the two stirring paddles 13 are lowered to different heights (20 mm and 100 mm), the discharge port 7 is closed, the cover body 9 is closed, and the valve and the discharge port 8 on the feed pipe 10 are opened; In this embodiment, the stirring head 13.2 of the stirring paddle 13 is made of rubber strip material.

[0067] S2. Slowly pump the wet powder material to be washed from the feed pipe 10, and the material filling volume does not exceed 70% of the total capacity of the centrifugal bucket 2. Start the drive motor I6 (the speed is set to 500 rpm), and the device separates the material. When the discharge speed of the discharge port 8 slows down or stops significantly (about 3 minutes), stop the drive motor I6; In each step of this embodiment, pure water is used as a washing liquid to wash the micro-nano powder.

[0068] S3, open the high-pressure water / hot air pipe 11, switch to the liquid inlet state, start the drive motor I6, stir for 3 minutes at a low speed of 10rpm, and wash the wet filter cake attached to the filter cloth 4 to the bottom of the centrifugal barrel 2 through the washing liquid introduced by the high-pressure water / hot air pipe 11. After the washing is complete, add the washing liquid through the feed pipe 10 at the same time, and stir, wash, soak and disperse the material several times by controlling the start / stop interval time of the drive motor II15. At this time, the speed of the drive motor II15 is 300rpm; S4, after washing and dispersion is completed, the driving motor II 15 is stopped, and the driving motor I 6 is started (the speed of the driving motor I 6 is set to 1000 rpm at this time), and the solid-liquid separation is performed again. When the discharge speed of the discharge port 8 is significantly slowed down or stopped (about 2 minutes), the driving motor I 6 is stopped; S5, repeating steps S3 and S4 until the washed material is in a powder state or meets the washing requirements, the washing requirements are: the pH of the filtrate is 5.5, the conductivity is 100 μs / cm, and the filter cake has no agglomeration in the solvent, then stop washing; S6, after further drying the washing liquid from the powder (1000rpm, 2min), open the discharge port 7, discharge the dried filter cake from the centrifugal barrel 2, turn on the drive motor I6, at a low speed (10rpm), start the lifting brush 14 to brush all the powder remaining on the filter cloth 4 to the bottom of the barrel and discharge it; S7, keep the centrifugal barrel 2 running at a low speed of 50rpm, switch the high-pressure water / hot air pipe 11 to the liquid inlet state, and start the lifting brush 14 to clean the filter cloth 4. After a certain period of time (about 1 minute), the high-pressure water / hot air pipe 11 is switched to the hot air inlet state, and the filter cloth 4 is air-dried with hot air (about 3 minutes).

[0069] After the silver powder is dispersed, washed and filtered by the method of this embodiment, the silver mud filter cake is loose after drying without agglomeration. The collection rate of dried silver powder is 99.7%. After pulverization, the particle size D10 is 0.5~1.1μm, D50 is 1.5~2.0μm, D90 is 3.0~3.5μm, the bulk density is 2.8g / mL, and the monitored nitrate content is <20ppm. The silver powder yield obtained by the device and method of this embodiment is higher, and the purity reaches electronic grade.

[0070] Embodiment 14 The present embodiment differs from the embodiment 13 in that: in the step S6, before starting the lifting brush 14, the high-pressure water / hot air pipe 11 is first switched to the hot air intake state, and hot air is first introduced to dry the powder remaining on the filter cloth 4.

[0071] Embodiment 15 This embodiment uses the same silver powder material as that of embodiment 13. The difference between this embodiment and embodiment 13 is that: In step S1, the two stirring paddles 13 are both lowered to a height of 50 mm; In step S2, when the material filling volume reaches 250% of the centrifugal bucket, the driving motor I6 is started, the speed is set to 1000 rpm, and the driving motor I6 is stopped after about 2 minutes; In step S3, when the material is stirred, washed, soaked and dispersed for several times, the speed of the driving motor II 15 is set to 400 rpm. In step S5, steps S3 and S4 are repeated until the washed material is in a powder state or the washing requirements are met. The washing requirements are: the pH of the filtrate is 5.6, the conductivity is 120 μs / cm, and the filter cake has no agglomerates in the solvent. Then, the washing is stopped, and the other steps are the same as those in Example 13.

[0072] After the silver powder was dispersed, washed and filtered by the method of this embodiment, the silver mud filter cake was relatively loose after drying without agglomeration. The collection rate of the dried silver powder was 99.8%. After pulverization, the particle size D10 was 0.6-1.0 μm, D50 was 1.5-1.8 μm, D90 was 2.8-3.5 μm, the bulk density was 2.8 g / mL, and the monitored nitrate content was <20 ppm.

[0073] Example 16 This embodiment uses the same silver powder material as that of embodiment 13. The difference between this embodiment and embodiment 13 is that: In step S1, the two stirring paddles 13 are both lowered to a height of 20 mm; In step S2, when the material filling volume reaches 250% of the centrifugal bucket, the driving motor I6 is started, the speed is set to 1500 rpm, and the driving motor I6 is stopped after about 1.5 minutes; In step S3, when the material is stirred, washed, soaked and dispersed for several times, the speed of the driving motor II 15 is set to 1000 rpm; In step S4, the speed of the driving motor I6 is set to 500 rpm, and the powder material is stirred and dispersed for 3 minutes. After the dispersion is completed, the speed of the driving motor I6 is adjusted to 1500 rpm / min, and then the solid-liquid separation is performed; In step S5, steps S3 and S4 are repeated until the material is washed to a powder state or the washing requirements are met, wherein the washing requirements are: the pH of the filtrate is 5.8, the conductivity is 80 μs / cm, and the filter cake has no agglomeration in the solvent, and the washing is stopped; In step S6, when the powder is further dehydrated, the speed of the driving motor I6 is set to 1500 rpm for 2 min. The remaining steps are the same as those in Example 13.

[0074] After the silver powder was dispersed, washed and filtered by the method of this embodiment, the silver mud filter cake was relatively loose after drying without agglomeration. The collection rate of the dried silver powder was 99.7%. After pulverization, the particle size D10 was 0.6-1.2 μm, D50 was 1.6-2.1 μm, D90 was 2.8-3.5 μm, the bulk density was 2.8 g / mL, and the monitored nitrate content was <15 ppm.

[0075] Embodiment 17 A method for washing and separating micro-nano powders, this embodiment takes washing, dispersing, and filtering micro-nano flocculent silver powder as an example, the solid content of the silver powder is 20% to 60%, the nitrate and organic impurities are 10% to 20%, the particle size D10 is 0.1 to 0.5 μm, D50 is 0.7 to 1.5 μm, D90 is 1.3 to 1.8 μm, the bulk density in the wet state is 1.5 to 2.0 g / mL, the pH is 5 to 8, and the conductivity is 45 ms / cm. The present scheme is further illustrated. This embodiment uses the same micro-nano powder washing and separation device as in Example 13.

[0076] The specific steps include: S1. Select a filter cloth 4 with a filtration accuracy of 1 μm according to the micro-nano powder to be washed, and then place the filter cloth 4 flat on the inner wall of the centrifugal barrel 2. After the stirring paddle 13 is lowered to a certain height, the two stirring paddles 13 are lowered to different heights (20 mm and 50 mm), the discharge port 7 is closed, the cover body 9 is closed, and the valve and the discharge port 8 on the feed pipe 10 are opened; S2. Slowly pump the wet powder material to be washed from the feed pipe 10, and the material filling volume does not exceed 30% of the total capacity of the centrifugal bucket 2. Start the drive motor I6 (the speed is set to 500 rpm), and the device separates the material. When the discharge speed of the discharge port 8 slows down or stops significantly (about 5 minutes), stop the drive motor I6; In each step of this embodiment, pure water is used as a washing liquid to wash the micro-nano powder.

[0077] S3, open the high-pressure water / hot air pipe 11, switch to the liquid inlet state, start the drive motor I6, stir for 3 minutes at a low speed of 10rpm, and wash the wet filter cake attached to the filter cloth 4 to the bottom of the centrifugal barrel 2 through the washing liquid introduced by the high-pressure water / hot air pipe 11. After the washing is complete, add washing liquid through the feed pipe 10 at the same time. When the material reaches 60% of the volume of the centrifugal barrel 2, stop the water inlet and stop the rotation of the centrifugal barrel 2. By controlling the start / stop interval time of the drive motor II15, the material is stirred, washed, soaked and dispersed several times. At this time, the speed of the drive motor II15 is 200rpm; S4, after washing and dispersion is completed, the driving motor II 15 is stopped, and the driving motor I 6 is started (the speed of the driving motor I 6 is set to 1500 rpm at this time), and the solid-liquid separation is performed again. When the discharge speed of the discharge port 8 is significantly slowed down or stopped (about 3 minutes), the driving motor I 6 is stopped; S5, repeating steps S3 and S4 until the washed material is in a powder state or meets the washing requirements, the washing requirements are: the pH of the filtrate is 6.1, the conductivity is 200 μs / cm, and the filter cake has no agglomeration in the solvent, then stop washing; S6, after further drying the washing liquid from the powder (1500rpm, 3min), open the discharge port 7, discharge the dried filter cake out of the centrifugal barrel 2, turn on the drive motor I6, at a low speed (50rpm), start the lifting brush 14 to brush all the powder remaining on the filter cloth 4 to the bottom of the barrel and discharge it; S7, keep the centrifugal barrel 2 running at a low speed of 50rpm, switch the high-pressure water / hot air pipe 11 to the hot air inlet state, use the hot air to air-dry the filter cloth 4 (about 4 minutes), and slowly lower the lifting brush 14, keep the brush head 14.1 of the lifting brush 14 in contact with the filter cloth 4, and use the brush head 14.1 for 1 minute to brush the remaining small amount of dry silver powder material on the filter cloth 4 to the bottom of the barrel. Switch the high-pressure water / hot air pipe 11 to the liquid inlet state, and start the lifting brush 14 at the same time to clean the filter cloth 4. After a certain period of time (about 1 minute), switch the high-pressure water / hot air pipe 11 to the hot air inlet state to dry the centrifugal barrel 2 and the filter cloth 4 for next use.

[0078] After the silver powder is dispersed, washed and filtered by the method of this embodiment, the silver mud filter cake is loose after drying without agglomeration. The collection rate of dried silver powder is 99.5%. After pulverization, the particle size D10 is 0.1~0.3μm, D50 is 0.7~1.2μm, D90 is 1.2~1.5μm, the bulk density is 2.2g / mL, and the monitored nitrate content is <20ppm. The silver powder yield obtained by the device and method of this embodiment is higher, and the purity reaches electronic grade.

[0079] Embodiment 18 A method for washing and separating micro-nano powders, this embodiment takes washing, dispersing and filtering calcium carbonate heavy calcium powder as an example, the solid content is 20% to 50%, the particle size D10 is 0.1 to 1.0 μm, D50 is 1.0 to 3.0 μm, D90 is 2.5 to 5.0 μm, and the bulk density in wet state is 0.5 to 1.2 g / mL micro-nano powder, further illustrating this scheme. This embodiment uses the same micro-nano powder washing and separation device as in Example 13.

[0080] The specific steps include: S1. Select a filter cloth 4 with a filtration accuracy of 20 μm according to the micro-nano powder to be washed, and then flatten the filter cloth 4 on the inner wall of the centrifugal barrel 2. After the stirring paddle 13 is lowered to a certain height, the two stirring paddles 13 are lowered to different heights (40 mm and 100 mm), the discharge port 7 is closed, the cover body 9 is closed, and the valve and the discharge port 8 on the feed pipe 10 are opened; S2. Slowly pump the wet powder material to be washed from the feed pipe 10, and the material filling volume does not exceed 60% of the total capacity of the centrifugal bucket 2. Start the drive motor I6 (the speed is set to 500 rpm), and the device separates the material. When the discharge speed of the discharge port 8 slows down or stops significantly (about 3 minutes), stop the drive motor I6; In each step of this embodiment, pure water is used as a washing liquid to wash the micro-nano powder.

[0081] S3, open the high-pressure water / hot air pipe 11, switch to the liquid inlet state, start the drive motor I6, stir for 3 minutes at a low speed of 10rpm, and wash the wet filter cake attached to the filter cloth 4 to the bottom of the centrifugal barrel 2 through the washing liquid introduced by the high-pressure water / hot air pipe 11. After the washing is complete, add washing liquid through the feed pipe 10 at the same time. When the material reaches 70% of the volume of the centrifugal barrel 2, stop the water inlet and stop the rotation of the centrifugal barrel 2. By controlling the start / stop interval time of the drive motor II15, the material is stirred, washed, soaked and dispersed several times. At this time, the speed of the drive motor II15 is 200rpm; S4, after washing and dispersion is completed, the driving motor II 15 is stopped, and the driving motor I 6 is started (the speed of the driving motor I 6 is set to 1500 rpm at this time), and the solid-liquid separation is performed again. When the discharge speed of the discharge port 8 is significantly slowed down or stopped (about 3 minutes), the driving motor I 6 is stopped; S5, repeating steps S3 and S4 until the washed material is in a powder state or meets the washing requirements, the washing requirements are: the pH and conductivity of the filtrate are close to pure water, and the filter cake has no agglomeration in the solvent, then stop washing; S6, after further drying the washing liquid from the powder (1500rpm, 3min), open the discharge port 7, discharge the dried filter cake out of the centrifugal barrel 2, turn on the drive motor I6, at a low speed (50rpm), start the lifting brush 14 to brush all the powder remaining on the filter cloth 4 to the bottom of the barrel and discharge it; S7, keep the centrifugal barrel 2 running at a low speed of 50rpm, switch the high-pressure water / hot air pipe 11 to the hot air inlet state, use the hot air to air-dry the filter cloth 4 (about 4 minutes), and slowly lower the lifting brush 14, keep the brush head 14.1 of the lifting brush 14 in contact with the filter cloth 4, and use the brush head 14.1 for 1 minute to brush the remaining small amount of dry silver powder material on the filter cloth 4 to the bottom of the barrel. Switch the high-pressure water / hot air pipe 11 to the liquid inlet state, and start the lifting brush 14 at the same time to clean the filter cloth 4. After a certain period of time (about 1 minute), switch the high-pressure water / hot air pipe 11 to the hot air inlet state to dry the centrifugal barrel 2 and the filter cloth 4 for next use.

[0082] After the heavy calcium powder was dispersed, washed and filtered by the method of this embodiment, the moisture content of the filter cake was 15%, the entire washing process was 25 minutes, the collection rate after drying was 99.2%, and the powder was relatively loose. After drying and powdering, the particle size D10 was 0.1-0.7 μm, D50 was 1.5-2.5 μm, D90 was 3.0-4.0 μm, the bulk density was 1.5 g / mL, and the impurity content was <20 ppm.

[0083] Comparative Example 1 This comparative example uses the same materials as in Example 13. After washing by a traditional filter press and manual stirring, the silver powder yield after drying is 99.1%, the particle size D10 is 0.5~1.5μm, D50 is 2.0~3.0μm, D90 is 3.0~4.5μm, the bulk density is 2.5g / mL, and the monitored nitrate content is <100ppm.

[0084] Comparative Example 2 This comparative example uses the same materials as in Example 17. After washing by a traditional filter press and manual stirring, the silver powder yield after drying is 98.1%, the particle size D10 is 0.3~0.7μm, D50 is 1.2~2.0μm, D90 is 2.5~3.5μm, the bulk density is 2.2g / mL, and the monitored nitrate content is <200ppm.

[0085] Comparative Example 3 This comparative example uses the same materials as in Example 18. After cleaning by a traditional filter press and manual stirring, the entire washing process takes 2 hours. The obtained filter cake has a drying moisture content of 45%, a collection rate of 97.5% after drying, D10 is 0.2~0.6μm, D50 is 1.5~2.5μm, D90 is 2.5~5.5μm, the bulk density is 1.6g / mL, and the impurity content is <60ppm.

[0086] It can be seen from the above embodiments and comparative examples that by adopting the device and method of the present invention, the cleaning efficiency of the powder is significantly improved and the purity of the powder after washing is high.

[0087] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification or equivalent change made to the above embodiment based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. Micro-nano powder washing and separation device, characterized by: The centrifugal bucket (2) comprises an outer barrel (1), a centrifugal bucket (2) and a cover body (9). A plurality of through holes I (3) are provided on the barrel wall of the centrifugal bucket (2). A filter cloth (4) is installed close to the inner wall of the centrifugal bucket (2). The bottom of the centrifugal bucket (2) is a smooth arc-shaped bottom surface. A discharge port (7) is provided at the center of the bottom of the centrifugal bucket (2). The bottom of the centrifugal bucket (2) is connected to a drive motor I (6) via a transmission assembly (5) passing through the outer barrel (1). The drive motor I (6) drives the centrifugal bucket (2) to rotate. A liquid discharge port (8) is provided at the bottom of the outer barrel (1). The cover body (9) is detachably connected to the outer barrel (1); a feed pipe (10) and a high-pressure water / hot air pipe (11) are connected to the cover body (9); a plurality of through holes II (12) are formed on the high-pressure water / hot air pipe (11); the through holes II (12) face the filter cloth (4); a stirring paddle (13) that can move up and down and a lifting brush (14) for brushing the wall of the centrifugal barrel (2) are mounted on the cover body (9); the stirring paddle (13) is driven by a driving motor II (15); and the lifting brush (14) is driven by a driving assembly (16) to reciprocate in the longitudinal direction of the centrifugal barrel (2) and rotate in the horizontal direction.

2. The micro-nano powder washing and separation device according to claim 1, characterized in that: The high-pressure water / hot air pipe (11) extends into the lower part of the centrifugal barrel (2), the through hole II (12) at the upper part of the high-pressure water / hot air pipe (11) faces upward, and the through hole II (12) at the lower part faces downward, and the water or hot air sprayed out by the high-pressure water / hot air pipe (11) covers the filter cloth (4) in the longitudinal direction of the barrel wall of the centrifugal barrel (2).

3. The micro-nano powder washing and separation device according to claim 2, characterized in that: The through hole II (12) has a diameter of 0.5-1.0 mm.

4. The micro-nano powder washing and separation device according to claim 1, characterized in that: The stirring paddle (13) comprises a detachable stirring rod (13.1) and a stirring head (13.2); the stirring paddle (13) comprises two stirring paddles, and the two stirring paddles (13) are symmetrically arranged on the cover body (9); the stirring head (13.2) is made of a rubber strip, a silicone strip or a polytetrafluoroethylene strip material.

5. The micro-nano powder washing and separation device according to claim 1, characterized in that: The cover body (9) is provided with a backwashing spray head (17), and a sight glass (18) is also installed on the cover body (9).

6. The micro-nano powder washing and separation device according to claim 1, characterized in that: The filtering accuracy of the filter cloth (4) is 0.1-2000 μm, and the filter cloth (4) is made of polypropylene, polyester or polytetrafluoroethylene.

7. The micro-nano powder washing and separation device according to claim 1, characterized in that: The roughness of the inner wall and the bottom surface of the centrifugal bucket (2) is less than 1Ra, and the angle between the bottom of the centrifugal bucket (2) and the horizontal plane is 10° to 30°.

8. A method for washing and separating micro-nano powders, characterized in that: Based on the micro-nano powder washing and separation device according to any one of claims 1 to 7, the device comprises the following steps: S1. Select a filter cloth (4) with a filtering accuracy that matches the micro-nano powder to be washed, and then place the filter cloth (4) flat against the inner wall of the centrifugal barrel (2). After the stirring paddle (13) is lowered to a certain height, the discharge port (7) and the cover (9) are closed, and the valve and the discharge port (8) on the feed pipe (10) are opened. S2. Slowly pump the wet powder material to be washed from the feed pipe (10), so that the material filling volume does not exceed 70% of the total capacity of the centrifugal bucket (2), start the drive motor I (6), and the device separates the material. When the discharge speed of the discharge port (8) is significantly slowed down or stopped, stop the drive motor I (6); S3, opening the high-pressure water / hot air pipe (11), switching to the liquid inlet state, starting the drive motor I (6), and in the low-speed state, washing liquid introduced through the high-pressure water / hot air pipe (11) is used to wash the wet filter cake attached to the filter cloth (4) and drop it to the bottom of the centrifugal barrel (2). After the washing is complete, washing liquid is added through the feed pipe (10) at the same time, and the material is stirred, washed, soaked and dispersed several times by controlling the start / stop interval time of the drive motor II (15); S4, after washing and dispersion is completed, the driving motor II (15) is stopped and the driving motor I (6) is started to perform solid-liquid separation again. When the discharge speed of the liquid discharge port (8) is significantly slowed down or stopped, the driving motor I (6) is stopped; S5, repeat steps S3 and S4 until the washed material is in a powder state or reaches the washing requirements, then stop washing; S6, after further drying the washing liquid from the powder, the discharge port (7) is opened to discharge the dried filter cake out of the centrifugal barrel (2), and the drive motor I (6) is turned on at a low speed, and the lifting brush (14) is started to brush all the powder remaining on the filter cloth (4) to the bottom of the barrel and discharge it; S7, the centrifugal barrel (2) is kept running at a low speed, the high-pressure water / hot air pipe (11) is switched to a liquid inlet state, and the lifting brush (14) is started to clean the filter cloth (4). After a certain period of time, the high-pressure water / hot air pipe (11) is switched to a hot air inlet state, and the filter cloth (4) is dried by hot air.

9. A method for washing and separating micro-nano powders according to claim 8, characterized in that: When the stirring paddle (13) is working, the distance between the end of the stirring paddle (13) and the filter cloth (4) is 20 to 50 mm.

10. The method for washing and separating micro-nano powders according to claim 8, characterized in that: When a plurality of stirring paddles (13) are mounted on the cover body (9), each stirring paddle (13) descends to a different height when in operation.

11. The method for washing and separating micro-nano powders according to claim 8, characterized in that: The washing liquid is one of pure water, ethanol, surfactant solution, a mixed solution of pure water and surfactant, or ethanol-water solution.

12. The method for washing and separating micro-nano powders according to claim 8, characterized in that: In step S5, the washing endpoint judgment criteria are: the pH of the filtrate is between 5 and 8, the conductivity is less than 500 μs / cm, and the filter cake has no agglomeration in the solvent.

13. The method for washing and separating micro-nano powders according to claim 8, characterized in that: In the step S6, before starting the lifting brush (14), the high-pressure water / hot air pipe (11) is first switched to the hot air intake state, and hot air is first introduced to dry the powder remaining on the filter cloth (4).

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