A post-treatment method for silver powder composite modification

Abstract

The present invention belongs to the technical field of silver powder modification methods, and particularly relates to a post-treatment method for silver powder composite modification, which comprises the following steps. Step 1: Prepare the silver powder to be modified by a reduction method. Step 2: Add the silver powder to be modified into a high-speed mixer, and then add surface modifier A to complete high-speed shaping and the first modification treatment. Step 3: Add the silver powder after high-speed shaping and the first modification treatment into a high-speed disperser, then add ethanol for dispersion, and then add surface modifier B for the second modification treatment to obtain a second modified mixed solution. Step 4: Filter the second modified mixed solution through the filtering device of the silver powder cleaning device, and then successively perform primary solid-liquid separation, ethanol cleaning, and secondary solid-liquid separation through the centrifugal device of the silver powder cleaning device, and dry the wet powder to obtain the modified silver powder. The beneficial effects of the present invention are as follows: The surface of the prepared modified silver powder is completely changed to be lipophilic, the dosage of the modifier is small, and there is no residual excess modifier.

Description

Technical Field

[0001] The present invention belongs to the technical field of silver powder modification methods, and particularly relates to a post-treatment method for silver powder composite modification. Background Art

[0002] Crystalline silicon solar cell silver paste mainly consists of four parts: silver powder conductive phase, glass powder binder phase, organic carrier, and additives. Among them, silver powder accounts for more than 90% of the total weight of the paste and is the most important component of the silver paste. As the conductive functional phase of crystalline silicon solar cell silver paste, in addition to the basic physical and chemical index requirements, the silver powder used also needs to have good sphericity and sufficient surface lipophilic modification.

[0003] At present, the modification process of silver powder mostly focuses on the synthesis process or modification in the aqueous phase mixture at the end of synthesis, while the research on the modification process of silver powder after drying is less. The common methods for modifying dried silver powder are solution infiltration, spray stirring, and steam coating. These modification methods have problems such as incomplete modification of silver powder, large dosage of modifiers, and more residues of modifiers. Therefore, a silver powder modification method that can make the modification of silver powder more sufficient, reduce the dosage of modifiers, and reduce the residues of modifiers is particularly important. Summary of the Invention

[0004] The purpose of the present invention is to solve the above problems and provide a post-treatment method for silver powder composite modification.

[0005] The present invention relates to a post-treatment method for silver powder composite modification, including the following steps:

[0006] Step 1: Add 350 kg of an aqueous solution of polyvinylpyrrolidone with a mass concentration of 6% to a reaction vessel. Start stirring, then add 1 kg of nano silver seeds, and synchronously and uniformly add 340 kg of an aqueous solution of silver nitrate with a mass concentration of 20% and 315 kg of an aqueous solution of vitamin C with a mass concentration of 12%. The addition time is controlled within 20 min. After sedimentation and solid-liquid separation, wash twice with deionized water and three times with absolute ethanol, and then dry to obtain silver powder to be modified;

[0007] Step 2: Add the silver powder to be modified into a high-speed mixer, and then add surface modifier A. Control the rotation speed of the high-speed mixer at 1200 - 1500 r / min and mix for 3 - 20 min to complete high-speed shaping and the first modification treatment;

[0008] Step 3: Add the silver powder after high-speed shaping and the first modification treatment into a high-speed disperser, then add ethanol for dispersion, and then add surface modifier B for the second modification treatment. Control the rotation speed of the high-speed disperser at 1000 - 1500 r / min and stir and disperse for 5 - 20 min to obtain a second modification mixture;

[0009] Step 4: Add the second modified mixture into the silver powder cleaning device. First, filter it through the filtering device of the silver powder cleaning device to remove silver powder particles with a particle size of more than 10 μm. Then, successively perform primary solid-liquid separation, ethanol cleaning, and secondary solid-liquid separation through the centrifugal device of the silver powder cleaning device, and dry the wet powder to obtain modified silver powder.

[0010] Preferably, the surface modifier A is at least one of stearic acid, palmitic acid, silver oleate, silver stearate, and silver caprylate, and the mass of the surface modifier A is 0.1% - 1% of the silver powder to be modified;

[0011] The surface modifier B is at least one of octadecylamine, oleylamine, decylamine, and cetylamine, and the mass of the surface modifier A is 0.1% - 1% of the silver powder to be modified;

[0012] The mass of the ethanol for dispersion is 50% - 100% of the silver powder to be modified.

[0013] Preferably, the silver powder cleaning device includes a centrifugal device, a filtering device, a vacuum suction pump, and a driving device;

[0014] The centrifugal device is placed on the ground through a support frame, the filtering device is fixedly connected to the top of the centrifugal device, and the vacuum suction pump and the driving device are fixedly connected to the same side of the centrifugal device in a top-down order.

[0015] Preferably, the centrifugal device includes a first cylinder, a second cylinder, and a scraping component;

[0016] A feed hole is opened at the top of the first cylinder, and one side of the scraping component is fixedly connected to the top of the first cylinder through three fixing rods in the feed hole;

[0017] The top of the second cylinder is open, and a plurality of arc-shaped filter plates are provided on the side of the second cylinder. The second cylinder rotates and moves up and down inside the first cylinder, and the side of the scraping component away from the feed hole is connected to the inner bottom of the second cylinder.

[0018] Preferably, the scraping component includes a fixed ring, a sliding sleeve rod, two push rods I, two push rods II, two push rods III, two scraping plates, and four stirring rods; the sliding rod and the rod sleeve of the sliding sleeve rod rotate and slide relative to each other;

[0019] The fixed circular ring is rotatably connected to the center of the bottom of the second cylinder body. The sliding rod of the first sliding sleeve rod passes through the fixed circular ring and is fixedly connected to the bottom of the second cylinder body. The sleeve of the first sliding sleeve rod is fixedly connected to the top of the first cylinder body in the feeding hole through three fixed rods. One side of each of the two first push rods is hinged to the fixed circular ring. The two second push rods are respectively hinged to one side of the sleeve of the first sliding sleeve rod close to the fixed circular ring. One side of each of the two first push rods away from the fixed circular ring is respectively hinged to the middle position of the two second push rods. One side of each of the two second push rods away from the first sliding sleeve rod is respectively hinged to the scraping plate. The third push rod is respectively hinged to the sleeve of the first sliding sleeve rod and the scraping plate above the second push rod;

[0020] One side of each of the second push rod and the third push rod away from the first sliding sleeve rod is fixedly connected to the stirring rod. Rotating grooves are formed on both the upper and lower sides of the scraping plate. The second push rod and the third push rod respectively drive the stirring rod to rotate in the rotating grooves.

[0021] Preferably, the filtering device includes a filtering cylinder body, a sieve plate and a feeding pipe;

[0022] The feeding pipe is fixedly connected to the top of the first cylinder body. The feeding pipe communicates with the first cylinder body through the feeding hole. One side of the feeding pipe away from the first cylinder body communicates with the filtering cylinder body. The sieve plate is fixedly connected inside the filtering cylinder body.

[0023] Preferably, the vacuum suction pump is communicated with the first cylinder body through a suction pipe.

[0024] Preferably, the driving device includes a first driving motor, a first sprocket, a second sprocket, an L-shaped support frame, a second driving motor, a gear and a second sliding sleeve rod;

[0025] The first driving motor is fixedly connected to one side of the first cylinder body. The first driving motor is drivingly connected to the first sprocket below it. The bottom of the second sprocket is rotatably connected to the circular base provided on the support frame. The first sprocket and the second sprocket are driven by a chain. The L-shaped support frame is fixedly connected above the second sprocket. The second driving motor, the gear and the sliding rod of the second sliding sleeve rod are all fixedly connected to the L-shaped support frame. One side of the sleeve of the second sliding sleeve rod close to the second sprocket is provided with teeth meshing with the gear. The output shaft of the second driving motor drives the gear to rotate. One side of the sleeve of the second sliding sleeve rod away from the second sprocket passes through the first cylinder body and is fixedly connected to the bottom of the second cylinder body. The sleeve of the second sliding sleeve rod is slidably and rotatably connected to the first cylinder body.

[0026] Preferably, a limiting groove is formed in the sliding rod of the second sliding sleeve rod, and a limiting structure is provided on the rod sleeve of the second sliding sleeve rod. The limiting structure is slidably connected to the limiting groove, and the limiting structure and the limiting groove jointly limit the relative rotation of the sliding rod and the rod sleeve of the second sliding rod sleeve.

[0027] Preferably, a liquid inlet is provided on one side of the first cylinder away from the air extraction pipe, and a control valve is provided on the liquid inlet; a liquid outlet is provided below one side surface of the cylinder, and the control valve is provided on the liquid outlet.

[0028] Compared with the prior art, the advantages and positive effects of the present invention are as follows:

[0029] Compared with the prior art, by using the post-treatment method for silver powder composite modification of the present invention,

[0030] (1) The surface of the modified silver powder prepared by the post-treatment method for silver powder composite modification is completely changed to be lipophilic, the dosage of the surface modifier is small, and there is no residue of the excess surface modifier;

[0031] (2) The post-treatment method for silver powder composite modification has a short time consumption, simple steps, and improves the production efficiency by using the silver powder cleaning device, and is suitable for large-scale industrial production;

[0032] (3) The filtering device of the silver powder cleaning device reduces the pressure in the first cylinder through the vacuum suction pump, so that the second modified mixed liquid can be quickly filtered through the sieve plate, improving the efficiency of silver powder modification;

[0033] (4) The centrifugal device of the silver powder cleaning device can take into account both solid-liquid separation and cleaning of silver powder. After the second modified mixed liquid completes one solid-liquid separation in the centrifugal device, there is no need to transfer the silver powder to other equipment for cleaning, nor to transfer the cleaned silver powder back to the centrifugal device for secondary solid-liquid separation, which greatly saves the time for silver powder transportation and thus improves the efficiency of silver powder modification. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments.

[0035] Figure 1 Schematic diagram of the silver powder cleaning device provided in Embodiment 1;

[0036] Figure 2 Internal structure diagram of the silver powder cleaning device provided in Embodiment 1;

[0037] Figure 3 Internal structure diagram of the second cylinder provided in Embodiment 1;

[0038] Figure 4Schematic diagram of the scraping component provided for Example 1;

[0039] Figure 5 Schematic diagram of the driving device provided for Example 1.

[0040] Explanation of reference numerals:

[0041] 1 - Centrifugal device, 2 - Filtering device, 3 - Vacuum suction pump, 4 - Driving device, 5 - First cylinder, 6 - Second cylinder, 7 - Scraping component, 8 - Feed hole, 9 - Fixed rod, 10 - Arc-shaped filter plate, 11 - Fixed ring, 12 - First sliding sleeve rod, 13 - First push rod, 14 - Second push rod; 15 - Third push rod, 16 - Scraper, 17 - Stirring rod, 18 - Rotating groove, 19 - Filter cylinder, 20 - Sieve plate, 21 - Feed pipe, 22 - Air extraction pipe, 23 - First driving motor, 24 - First sprocket, 25 - Second sprocket, 26 - L-shaped support frame, 27 - Second driving motor, 28 - Gear, 29 - Second sliding sleeve rod, 30 - Chain, 31 - Limit groove, 32 - Limiting structure, 33 - Liquid inlet, 34 - Control valve, 35 - Liquid outlet, 36 - Support frame, 37 - Circular base. Detailed implementation manners

[0042] In order to more clearly understand the above objects, features and advantages of the present invention, the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0043] In the following description, many specific details are set forth in order to fully understand the present invention. However, the present invention may be implemented in other ways different from those described herein. Therefore, the present invention is not limited by the specific embodiments disclosed in the following specification.

[0044] Example 1

[0045] A post-treatment method for silver powder composite modification, comprising the following steps:

[0046] Step 1: Add 350 kg of an aqueous solution of polyvinylpyrrolidone with a mass concentration of 6% into a reaction vessel. Start stirring, then add 1 kg of nano silver seeds, and synchronously and uniformly add 340 kg of an aqueous solution of silver nitrate with a mass concentration of 20% and 315 kg of an aqueous solution of vitamin C with a mass concentration of 12%. The addition time is controlled within 20 min. After sedimentation and solid-liquid separation, wash twice with deionized water and three times with absolute ethanol, and then perform drying to obtain the silver powder to be modified.

[0047] Step 2: Add the silver powder to be modified into a high-speed mixer, then add surface modifier A, control the rotation speed of the high-speed mixer to be 1200 r / min, and mix for 20 min to complete high-speed shaping and the first modification treatment.

[0048] Step 3: Add the silver powder after high-speed shaping and the first modification treatment into a high-speed disperser, then add ethanol for dispersion, and then add surface modifier B for the second modification treatment. Control the rotation speed of the high-speed disperser at 1500 r / min and stir and disperse for 10 min to obtain the second modified mixture.

[0049] Step 4: Add the second modified mixture into the silver powder cleaning device. First, filter it through the filter device 2 of the silver powder cleaning device to remove silver powder particles with a particle size above 10 μm. Then, successively perform primary solid-liquid separation, ethanol cleaning, and secondary solid-liquid separation through the centrifugal device 1 of the silver powder cleaning device, and dry the wet powder to obtain the modified silver powder.

[0050] Surface modifier A is stearic acid, and the mass of surface modifier A is 0.5% of the silver powder to be modified.

[0051] Surface modifier B is oleylamine, and the mass of surface modifier B is 0.5% of the silver powder to be modified.

[0052] The mass of ethanol used for dispersion is 100% of the silver powder to be modified.

[0053] As Figures 1 - 5 shown, the silver powder cleaning device includes a centrifugal device 1, a filter device 2, a vacuum suction pump 3, and a driving device 4.

[0054] As Figures 1 - 5 shown, the centrifugal device 1 is placed on the ground through a support frame 36, the filter device 2 is fixedly connected to the top of the centrifugal device 1, and the vacuum suction pump 3 and the driving device 4 are fixedly connected to the same side of the centrifugal device 1 in the order from top to bottom.

[0055] As Figures 1 - 5 shown, the centrifugal device 1 includes a first cylinder 5, a second cylinder 6, and a scraping assembly 7.

[0056] As Figures 1 - 5 shown, a feed hole 8 is opened at the top of the first cylinder 5, and one side of the scraping assembly 7 is fixedly connected to the top of the first cylinder 5 through three fixing rods 9 in the feed hole 8.

[0057] As Figures 1 - 5 shown, the top of the second cylinder 6 is open, and a plurality of arc-shaped filter plates 10 are provided on the side of the second cylinder 6. The second cylinder 6 rotates and moves up and down inside the first cylinder 5, and the side of the scraping assembly 7 away from the feed hole 8 is connected to the inner bottom of the second cylinder 6.

[0058] As Figures 1 - 5 shown, the scraping assembly 7 includes a fixed ring 11, a sliding sleeve rod 12, two push rods 13, two push rods 14, two push rods 15, two scraping plates 16, and four stirring rods 17; the sliding rod and the rod sleeve of the sliding sleeve rod 12 rotate and slide relative to each other.

[0059] As Figures 1 - 5 shown, the fixed ring 11 is rotatably connected to the center of the bottom of the second cylinder body 6. The slide rod of the first slide sleeve rod 12 passes through the fixed ring 11 and is fixedly connected to the bottom of the second cylinder body 6. The rod sleeve of the first slide sleeve rod 12 is fixedly connected to the top of the first cylinder body 5 in the feed hole 8 through three fixed rods 9. One side of each of the two first push rods 13 is hinged to the fixed ring 11. The two second push rods 14 are respectively hinged to one side of the rod sleeve of the first slide sleeve rod 12 close to the fixed ring 11. One side of the two first push rods 13 away from the fixed ring 11 is respectively hinged to the middle position of the two second push rods 14. One side of the two second push rods 14 away from the first slide sleeve rod 12 is respectively hinged to the scraper 16. The third push rod 15 is respectively hinged to the rod sleeve of the first slide sleeve rod 12 and the scraper 16 above the second push rod 14.

[0060] As Figures 1 - 5 shown, one side of the second push rod 14 and the third push rod 15 away from the first slide sleeve rod 12 are both fixedly connected to the stirring rod 17. Rotating grooves 18 are formed on both the upper and lower sides of the scraper 16. The second push rod 14 and the third push rod 15 respectively drive the stirring rod 17 to rotate in the rotating groove 18.

[0061] As Figures 1 - 5 shown, the filtering device 2 includes a filtering cylinder body 19, a sieve plate 20 and a feeding pipe 21;

[0062] As Figures 1 - 5 shown, the feeding pipe 21 is fixedly connected to the top of the first cylinder body 5. The feeding pipe 21 is communicated with the first cylinder body 5 through the feed hole 8. One side of the feeding pipe 21 away from the first cylinder body 5 is communicated with the filtering cylinder body 19. The sieve plate 20 is fixedly connected inside the filtering cylinder body 19.

[0063] As Figures 1 - 5 shown, the vacuum filtration pump 3 is communicated with the first cylinder body 5 through an air extraction pipe 22.

[0064] As Figures 1 - 5 shown, the driving device 4 includes a first driving motor 23, a first sprocket 24, a second sprocket 25, an L-shaped support frame 26, a second driving motor 27, a gear 28 and a second slide sleeve rod 29.

[0065] As Figures 1 - 5As shown in the figure, the first driving motor 23 is fixedly connected to the side surface of the first cylinder 5. The lower part of the first driving motor 23 is drivingly connected to the first sprocket 24. The bottom of the second sprocket 25 is rotatably connected to the circular base 37 provided on the support frame 36. The first sprocket 24 and the second sprocket 25 are driven by a chain 30. The L-shaped support frame 26 is fixedly connected above the second sprocket 25. The second driving motor 27, the gear 28 and the slide rod of the second sliding sleeve rod 29 are all fixedly connected to the L-shaped support frame 26. A tooth is provided on one side of the sleeve of the second sliding sleeve rod 29 close to the second sprocket 25 and meshes with the gear 28. The output shaft of the second driving motor 27 drives the gear 28 to rotate. The side of the sleeve of the second sliding sleeve rod 29 far from the second sprocket 25 passes through the first cylinder 5 and is fixedly connected to the bottom of the second cylinder 6. The sleeve of the second sliding sleeve rod 29 is slidably and rotatably connected to the first cylinder 5.

[0066] As Figures 1 - 5 shown in the figure, a limiting groove 31 is provided on the slide rod of the second sliding sleeve rod 29, and a limiting structure 32 is provided on the sleeve of the second sliding sleeve rod 29. The limiting structure 32 is slidably connected in the limiting groove 31. The limiting structure 32 and the limiting groove 31 jointly limit the relative rotation of the slide rod and the sleeve of the second sliding rod sleeve.

[0067] As Figures 1 - 5 shown in the figure, a liquid inlet 33 is provided on the side of the first cylinder 5 away from the air extraction pipe 22, and a control valve 34 is provided on the liquid inlet 33; a liquid outlet 35 is provided below the side surface of the first cylinder 5, and a control valve 34 is provided on the liquid outlet 35.

[0068] The working principle of the silver powder cleaning device is as follows:

[0069] Filtration: Turn on the vacuum filtration pump 3, and then add the second modified mixed liquid into the filtration cylinder 19. Since the pressure in the first cylinder 5 decreases, the second modified mixed liquid passes through the sieve plate 20 faster, and silver powder particles with a particle size of more than 10 μm are removed.

[0070] Solid-liquid separation: The filtered second modified mixed liquid passes through the feed pipe 21 and the feed hole 8 in sequence and enters the second cylinder 6; start the second driving motor 27. The second driving motor 27 drives the sleeve of the second sliding sleeve rod 29 to rise through the gear 28, so that the second cylinder 6 rises in the first cylinder 5. At the same time, the fixed ring 11 moves upward, and the first push rod 13 is pushed to push the second push rod 14 perpendicular to the first sliding sleeve rod 12, and the scraper 16 is close to the inner wall of the second cylinder 6. Turn on the first driving motor 23, drive the second sprocket 25 to rotate through the first sprocket 24, so as to drive the L-shaped support frame 26, the second sliding sleeve rod 29 to rotate and the second cylinder 6 to rotate. The second cylinder 6 and the scraper 16 rotate relative to each other. The second cylinder 6 separates the second modified mixed liquid into solid and liquid. The scraper 16 scrapes off the silver powder on the inner wall of the second cylinder 6 during solid-liquid separation. The liquid enters the first cylinder 5 and is discharged from the silver powder cleaning device through the liquid outlet 35.

[0071] Ethanol cleaning: Close the liquid outlet 35, start the second drive motor 27 again. The second drive motor 27 drives the sleeve of the second sliding sleeve rod 29 to descend through the gear 28, so that the second cylinder 6 descends in the first cylinder 5; at the same time, the fixed ring 11 moves downward, pulls the second push rod 14 through the first push rod 13 to form an angle with the first sliding sleeve rod 12, and both the second push rod 14 and the third push rod 15 drive the stirring rod 17 to rotate, and the stirring rod 17 forms an angle with the scraper 16; Add ethanol into the first cylinder 5 from the liquid inlet 33, and the ethanol flows in the first cylinder 5 and the second cylinder 6 through the arc-shaped filter plate 10. The rotation of the second cylinder 6 drives the silver powder in the barrel to rotate relative to the stirring rod 17 and the scraper 16, so that the silver powder is dispersed and cleaned in the ethanol.

[0072] Example 2

[0073] The difference between this example and Example 1 is that:

[0074] Step 2: Add the silver powder to be modified into a high-speed mixer, then add surface modifier A, control the rotation speed of the high-speed mixer to be 1400 r / min, and mix for 15 min to complete high-speed shaping and the first modification treatment;

[0075] Step 3: Add the silver powder after high-speed shaping and the first modification treatment into a high-speed disperser, then add ethanol for dispersion, and then add surface modifier B for the second modification treatment. Control the rotation speed of the high-speed disperser to be 1200 r / min, stir and disperse for 18 min to obtain the second modified mixed solution;

[0076] The surface modifier A is palmitic acid, and the mass of the surface modifier A is 1% of the silver powder to be modified;

[0077] The surface modifier B is decylamine, and the mass of the surface modifier B is 0.8% of the silver powder to be modified;

[0078] The mass of ethanol used for dispersion is 60% of the silver powder to be modified.

[0079] Example 3

[0080] The difference between this example and Example 1 is that:

[0081] Step 2: Add the silver powder to be modified into a high-speed mixer, then add surface modifier A, control the rotation speed of the high-speed mixer to be 1500 r / min, and mix for 10 min to complete high-speed shaping and the first modification treatment;

[0082] Step 3: Add the silver powder after high-speed shaping and the first modification treatment into a high-speed disperser, then add ethanol for dispersion, and then add surface modifier B for the second modification treatment. Control the rotation speed of the high-speed disperser to be 1000 r / min, stir and disperse for 20 min to obtain the second modified mixed solution;

[0083] The surface modifier A is silver stearate and silver octanoate, and the mass of the surface modifier A is 0.8% of the silver powder to be modified;

[0084] The surface modifier B is octadecylamine, and the mass of the surface modifier B is 0.5% of the silver powder to be modified;

[0085] The mass of ethanol for dispersion is 50% of the silver powder to be modified.

[0086] Example 4

[0087] The difference between this example and Example 1 is that the surface modifier B is cetylamine.

[0088] Performance test

[0089] The silver powder to be modified and the modified silver powder prepared in Examples 1 to 4 were subjected to particle size distribution, loose bulk density, tapped density, specific surface area, loss on ignition and water contact angle detection, and the detection results are shown in Table 1.

[0090] Table 1

[0091]

[0092] It can be seen from Table 1 that compared with the silver powder to be modified, the loss on ignition of the modified silver powder only increases by 0.011% - 0.02%, changes from hydrophilic to completely hydrophobic, has a narrower particle size distribution, and a higher tapped density.

[0093] The above is only a preferred embodiment of the present invention, and it is not a limitation of the present invention in other forms. Any person skilled in the art may use the disclosed technical content to make changes or modifications into equivalent embodiments with equivalent changes and apply them to other fields. However, as long as it does not depart from the technical content of the technical solution of the present invention, any simple modification and equivalent change made to the above embodiments according to the technical essence of the present invention still belong to the protection scope of the technical solution of the present invention.

Claims

1. A post-treatment method for silver powder composite modification, characterized in that, It includes the following steps: Step 1: Add 350 kg of an aqueous solution of polyvinylpyrrolidone with a mass concentration of 6% into a reaction vessel; start stirring, then add 1 kg of nano silver seeds, and synchronously and uniformly add 340 kg of an aqueous solution of silver nitrate with a mass concentration of 20% and 315 kg of an aqueous solution of vitamin C with a mass concentration of 12%. The addition time is controlled within 20 min. After sedimentation and solid-liquid separation, wash twice with deionized water and three times with absolute ethanol, and then dry to obtain the silver powder to be modified; Step 2: Add the silver powder to be modified into a high-speed mixer, then add surface modifier A, control the rotation speed of the high-speed mixer at 1200 - 1500 r / min, and mix for 3 - 20 min to complete high-speed shaping and the first modification treatment; Step 3: Add the silver powder after high-speed shaping and the first modification treatment into a high-speed disperser, then add ethanol for dispersion, and then add surface modifier B for the second modification treatment. Control the rotation speed of the high-speed disperser at 1000 - 1500 r / min, and stir and disperse for 5 - 20 min to obtain the second modified mixture; Step 4: Add the second modified mixture into a silver powder cleaning device. The silver powder cleaning device includes a centrifugal device (1), a filtering device (2), a vacuum suction pump (3), and a driving device (4); first filter through the filtering device (2) of the silver powder cleaning device to remove silver powder particles with a particle size above 10 μm; then sequentially perform primary solid-liquid separation, ethanol cleaning, and secondary solid-liquid separation through the centrifugal device (1) of the silver powder cleaning device, and dry the wet powder to obtain the modified silver powder; The surface modifier A is at least one of stearic acid, palmitic acid, silver oleate, silver stearate, and silver octanoate, and the mass of the surface modifier A is 0.1% - 1% of the silver powder to be modified; the surface modifier B is at least one of octadecylamine, oleylamine, decylamine, and cetylamine, and the mass of the surface modifier B is 0.1% - 1% of the silver powder to be modified; the mass of the ethanol used for dispersion is 50% - 100% of the silver powder to be modified; The centrifugal device (1) is placed on the ground through a support frame (36), the filtering device (2) is fixedly connected to the top of the centrifugal device (1), and the vacuum suction pump (3) and the driving device (4) are fixedly connected to the same side of the centrifugal device (1) in order from top to bottom; The centrifugal device (1) includes a first cylinder (5), a second cylinder (6), and a scraping assembly (7); a feed hole (8) is opened at the top of the first cylinder (5), and one side of the scraping assembly (7) is fixedly connected to the top of the first cylinder (5) through three fixing rods (9) in the feed hole (8); the top of the second cylinder (6) is open, and a plurality of arc-shaped filter plates (10) are provided on the side of the second cylinder (6). The second cylinder (6) rotates and moves up and down inside the first cylinder (5), and the side of the scraping assembly (7) away from the feed hole (8) is connected to the inner bottom of the second cylinder (6); The scraping assembly (7) includes a fixed circular ring (11), a first sliding sleeve rod (12), two first push rods (13), two second push rods (14), two third push rods (15), two scraping plates (16) and four stirring rods (17); the slide rod and the rod sleeve of the first sliding sleeve rod (12) rotate and slide relative to each other; the fixed circular ring (11) is rotatably connected to the center of the bottom of the second cylinder (6), the slide rod of the first sliding sleeve rod (12) passes through the fixed circular ring (11) and is fixedly connected to the bottom of the second cylinder (6), and the rod sleeve of the first sliding sleeve rod (12) is fixedly connected to the top of the first cylinder (5) in the feed hole (8) through the three fixed rods (9). One side of each of the two first push rods (13) is hinged to the fixed circular ring (11), and each of the two second push rods (14) is hinged to one side of the rod sleeve of the first sliding sleeve rod (12) close to the fixed circular ring (11). One side of each of the two first push rods (13) away from the fixed circular ring (11) is hinged to the middle position of each of the two second push rods (14), and one side of each of the two second push rods (14) away from the first sliding sleeve rod (12) is hinged to the scraping plate (16). The third push rods (15) are respectively hinged to the rod sleeve of the first sliding sleeve rod (12) and the scraping plate (16) above the second push rods (14); one side of each of the second push rods (14) and the third push rods (15) away from the first sliding sleeve rod (12) is fixedly connected to the stirring rod (17). Rotating grooves (18) are formed on both the upper and lower sides of the scraping plate (16), and the second push rods (14) and the third push rods (15) drive the stirring rods (17) to rotate in the rotating grooves (18).

2. The post-treatment method for silver powder composite modification according to claim 1, wherein The filtering device (2) includes a filtering cylinder body (19), a sieve plate (20) and a feed pipe (21); the feed pipe (21) is fixedly connected to the top of the first cylinder (5), the feed pipe (21) is communicated with the first cylinder (5) through the feed hole (8), one side of the feed pipe (21) away from the first cylinder (5) is communicated with the filtering cylinder body (19), and the sieve plate (20) is fixedly connected inside the filtering cylinder body (19).

3. The post-treatment method for silver powder composite modification according to claim 2, wherein The vacuum suction filter pump (3) is communicated with the first cylinder (5) through a suction pipe (22).

4. The post-treatment method for silver powder composite modification according to claim 3, wherein The driving device (4) includes a first driving motor (23), a first sprocket (24), a second sprocket (25), an L-shaped support frame (26), a second driving motor (27), a gear (28), and a second sliding sleeve rod (29); the first driving motor (23) is fixedly connected to the side of the first cylinder (5), the first driving motor (23) is drivingly connected to the first sprocket (24) below it, the bottom of the second sprocket (25) is rotatably connected to a circular base (37) provided on the support frame (36), the first sprocket (24) and the second sprocket (25) are driven by a chain (30), the L-shaped support frame (26) is fixedly connected above the second sprocket (25), the second driving motor (27), the gear (28), and the slide rod of the second sliding sleeve rod (29) are all fixedly connected to the L-shaped support frame (26), a tooth is provided on one side of the sleeve of the second sliding sleeve rod (29) close to the second sprocket (25) and meshes with the gear (28), the output shaft of the second driving motor (27) drives the gear (28) to rotate, the sleeve of the second sliding sleeve rod (29) on the side far from the second sprocket (25) passes through the first cylinder (5) and is fixedly connected to the bottom of the second cylinder (6), and the sleeve of the second sliding sleeve rod (29) is slidably and rotatably connected to the first cylinder (5).

5. The post-treatment method for silver powder composite modification according to claim 4, characterized in that, A limiting groove (31) is provided on the slide rod of the second sliding sleeve rod (29), a limiting structure (32) is provided on the sleeve of the second sliding sleeve rod (29), the limiting structure (32) is slidably connected in the limiting groove (31), and the limiting structure (32) and the limiting groove (31) jointly limit the relative rotation of the slide rod and the sleeve of the second sliding sleeve rod.

6. The post-treatment method for silver powder composite modification according to claim 5, characterized in that, The first cylinder (5) is provided with a liquid inlet (33) on the side far from the air extraction pipe (22), and a control valve (34) is provided on the liquid inlet (33); a liquid outlet (35) is provided below the side of the first cylinder (5), and a control valve (34) is also provided on the liquid outlet (35).

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