Silver powder composite modification post-treatment method

Abstract

The invention belongs to the technical field of silver powder modification methods, and particularly relates to a silver powder composite modification post-treatment method which comprises the following steps: step 1, preparing to-be-modified silver powder by a reduction method; secondly, silver powder to be modified is added into a high-speed mixer, then a surface modifier A is added, and high-speed shaping and first-time modification treatment are completed; thirdly, the silver powder obtained after high-speed shaping and first-time modification treatment is added into a high-speed dispersion machine, then ethyl alcohol is added for dispersion, a surface modifier B is added for second-time modification treatment, and second-time modified mixed liquid is obtained; and fourthly, the second modified mixed solution is filtered through a filtering device of a silver powder cleaning device, then primary solid-liquid separation, ethanol cleaning and secondary solid-liquid separation are sequentially conducted through a centrifugal device of the silver powder cleaning device, wet powder is dried, and the modified silver powder is prepared. The method has the beneficial effects that the surface of the prepared modified silver powder is thoroughly changed into lipophilicity, the using amount of the modifier is small, and no residual modifier is left.

Description

Technical Field

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

[0002] Crystalline silicon solar electrode silver paste is mainly composed of four parts: silver powder conductive phase, glass powder bonding phase, organic carrier and additives. Silver powder accounts for more than 90% of the total weight of the paste and is the main component of the silver paste. As the conductive functional phase of crystalline silicon solar electrode silver paste, the silver powder used must have good sphericity and sufficient surface lipophilic modification in addition to the basic physical and chemical index requirements.

[0003] At present, the modification process of silver powder is mostly concentrated in the synthesis process, or modified in the aqueous phase mixture at the end of the synthesis, while there are few studies on the modification process of silver powder after drying. The common methods for modifying dried silver powder are solution infiltration, spray stirring, and steam coating. These modification methods have the problems of incomplete modification of silver powder, large amount of modifier, and large amount of modifier residue. Therefore, a silver powder modification method that makes the silver powder modification more complete, reduces the amount of modifier, and reduces the modifier residue is particularly important. Summary of the invention

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

[0005] The present invention relates to a silver powder composite modification post-treatment method, comprising the following steps: Step 1: Add 350kg of 6% polyvinyl pyrrolidone aqueous solution into the reaction container. Start stirring, then add 1kg of nano silver seed crystals, and add 340kg of 20% silver nitrate aqueous solution and 315kg of 12% vitamin C aqueous solution simultaneously at a uniform speed, and the adding time is controlled within 20min. After sedimentation and solid-liquid separation, wash twice with deionized water, wash three times with anhydrous ethanol, and 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 the surface modifier A, control the speed of the high-speed mixer to 1200-1500 r / min, mix for 3-20 minutes, and complete the 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 speed of the high-speed disperser to 1000-1500r / min, stir and disperse for 5-20min, and obtain the second modified mixed solution; Step 4: Add the second modified mixed liquid to 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 pass it through the centrifugal device of the silver powder cleaning device to perform a solid-liquid separation, ethanol cleaning and a second solid-liquid separation in sequence, and dry the wet powder to obtain modified silver powder.

[0006] Preferably, 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% to 1% of the silver powder to be modified; The surface modifier B is at least one of octadecylamine, oleylamine, decylamine and hexadecylamine, and the mass of the surface modifier A is 0.1% to 1% of the silver powder to be modified; The mass of the dispersing ethanol is 50% to 100% of the silver powder to be modified.

[0007] Preferably, the silver powder cleaning device comprises a centrifugal device, a filtering device, a vacuum filtration pump and a driving device; 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 filtration pump and the driving device are fixedly connected to the same side of the centrifugal device in order from top to bottom.

[0008] Preferably, the centrifugal device comprises a cylinder body 1, a cylinder body 2 and a scraping assembly; A feed hole is provided at the top of the cylinder body 1, and one side of the scraper assembly is fixedly connected to the top of the cylinder body 1 through three fixing rods in the feed hole; The top of the second cylinder is open, and a plurality of arc-shaped filter plates are arranged on the side of the second cylinder. The second cylinder rotates and moves up and down in the first cylinder, and the side of the scraping assembly away from the feed hole is connected to the bottom of the second cylinder.

[0009] Preferably, the scraping assembly comprises a fixed ring, a sliding sleeve rod 1, two push rods 1, two push rods 2, two push rods 3, two scrapers and four stirring rods; the sliding rod and the rod sleeve of the sliding sleeve rod 1 rotate and slide relative to each other; The fixed ring is rotatably connected to the center position of the bottom of the cylinder body 2, the sliding rod of the sliding sleeve rod 1 passes through the fixed ring and is fixedly connected to the bottom of the cylinder body 2, the rod sleeve of the sliding sleeve rod 1 is fixedly connected to the top of the cylinder body 1 in the feeding hole through the three fixed rods, one side of the two push rods 1 is respectively hinged to the fixed ring, the two push rods 2 are respectively hinged to the side of the rod sleeve of the sliding sleeve rod 1 close to the fixed ring, the two push rods 1 are respectively hinged to the middle position of the two push rods 2 on the side away from the fixed ring, the two push rods 2 are respectively hinged to the scraper on the side away from the sliding sleeve rod 1, and the push rod 3 is respectively hinged to the rod sleeve of the sliding sleeve rod 1 and the scraper above the push rod 2; The push rods 2 and 3 are fixedly connected to the stirring rod at the sides away from the sliding sleeve rod 1, and rotation grooves are provided on the upper and lower sides of the scraper. The push rods 2 and 3 respectively drive the stirring rod to rotate in the rotation grooves.

[0010] Preferably, the filtering device comprises a filtering cylinder, a sieve plate and a feed pipe; The feed pipe is fixedly connected to the top of the cylinder body 1, the feed pipe is communicated with the cylinder body 1 through the feed hole, the side of the feed pipe away from the cylinder body 1 is communicated with the filter cylinder body, and the screen plate is fixedly connected in the filter cylinder body.

[0011] Preferably, the vacuum filtration pump is connected to the cylinder through a suction pipe.

[0012] Preferably, the driving device comprises a driving motor 1, a sprocket 1, a sprocket 2, an L-shaped support frame, a driving motor 2, a gear and a sliding sleeve rod 2; The driving motor 1 is fixedly connected to a side surface of the cylinder body, the lower part of the driving motor 1 is drivingly connected to the sprocket 1, the bottom of the sprocket 2 is rotatably connected to a circular base provided on the support frame, the sprocket 1 and the sprocket 2 are driven by a chain, the L-shaped support frame is fixedly connected to the top of the sprocket 2, the driving motor 2, the gear and the sliding rod of the sliding sleeve rod 2 are all fixedly connected to the L-shaped support frame, the rod sleeve of the sliding sleeve rod 2 is provided with teeth on the side close to the sprocket 2 that meshes with the gear, the output shaft of the driving motor 2 drives the gear to rotate, the rod sleeve of the sliding sleeve rod 2 is away from the sprocket 2 and passes through the cylinder body 1 and is fixedly connected to the bottom of the cylinder body 2, and the rod sleeve of the sliding sleeve rod 2 is slidably and rotatably connected to the cylinder body 1.

[0013] Preferably, the sliding rod of the sliding sleeve rod 2 is provided with a limiting groove, and the rod sleeve of the sliding sleeve rod 2 is provided with a limiting structure, the limiting structure is slidably connected in 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 sliding rod sleeve 2.

[0014] Preferably, the cylinder body is provided with a liquid inlet on a side away from the exhaust pipe, and a control valve is provided on the liquid inlet; a liquid outlet is provided at the lower part of a side surface of the cylinder body, and the control valve is provided on the liquid outlet.

[0015] Compared with the prior art, the advantages and positive effects of the present invention are: Compared with the prior art, the silver powder composite modification post-treatment method of the present invention can (1) The surface of the modified silver powder prepared by the silver powder composite modification post-treatment method is completely lipophilic, the amount of surface modifier used is small, and there is no excess surface modifier residue; (2) The silver powder composite modification post-treatment method is time-consuming, simple in steps, and utilizes a silver powder cleaning device to improve production efficiency, making it suitable for large-scale industrial production; (3) The filtering device of the silver powder cleaning device reduces the pressure in the cylinder through a vacuum filtration pump, so that the second modified mixed liquid can be quickly filtered through the sieve plate, thereby improving the efficiency of silver powder modification; (4) The centrifugal device of the silver powder cleaning device can take into account both solid-liquid separation and silver powder cleaning at the same time. After the second modified mixed liquid completes a solid-liquid separation in the centrifugal device, there is no need to transfer the silver powder to other equipment for cleaning, nor is there any need to transfer the cleaned silver powder back to the centrifugal device for a second solid-liquid separation. This saves the time of silver powder transportation to a great extent, thereby improving the efficiency of silver powder modification. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solution of the embodiment of the present invention, the following briefly introduces the drawings required for describing the embodiment. Figure 1 A schematic diagram of a silver powder cleaning device provided in Example 1; Figure 2 This is a diagram showing the internal structure of the silver powder cleaning device provided in Example 1; Figure 3 The internal structure diagram of the cylinder 2 provided in Example 1; Figure 4 A schematic diagram of a scraping assembly provided in Example 1; Figure 5 Schematic diagram of the driving device provided in Example 1.

[0017] Description of reference numerals: 1—centrifugal device, 2—filter device, 3—vacuum filter pump, 4—drive device, 5—cylinder body 1, 6—cylinder body 2, 7—scraping assembly, 8—feeding hole, 9—fixed rod, 10—arc filter plate, 11—fixed ring, 12—sliding sleeve rod 1, 13—push rod 1, 14—push rod 2; 15—push rod 3, 16—scraper, 17—stirring rod, 18—rotating groove, 19—filter cylinder, 20—sieve plate, 21—feeding pipe, 22—exhaust pipe, 23—drive motor 1, 24—sprocket wheel 1, 25—sprocket wheel 2, 26—L-shaped support frame, 27—drive motor 2, 28—gear, 29—sliding sleeve rod 2, 30—chain, 31—limiting groove, 32—limiting structure, 33—liquid inlet, 34—control valve, 35—liquid outlet, 36—support frame, 37—circular base. DETAILED DESCRIPTION

[0018] In order to more clearly understand the above-mentioned objects, features and advantages of the present invention, the present invention is further described below with reference to the accompanying drawings and embodiments.

[0019] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways than those described herein. Therefore, the present invention is not limited to the specific embodiments of the following disclosure.

[0020] Example 1 A silver powder composite modification post-treatment method comprises the following steps: Step 1: Add 350kg of 6% polyvinyl pyrrolidone aqueous solution into the reaction container. Start stirring, then add 1kg of nano silver seed crystals, and add 340kg of 20% silver nitrate aqueous solution and 315kg of 12% vitamin C aqueous solution simultaneously at a uniform speed, and the adding time is controlled within 20min. After sedimentation and solid-liquid separation, wash twice with deionized water, wash three times with anhydrous ethanol, and dry to obtain the silver powder to be modified.

[0021] Step 2: Add the silver powder to be modified into a high-speed mixer, then add the surface modifier A, control the speed of the high-speed mixer to 1200r / min, mix for 20min, and complete the high-speed shaping and the first modification treatment.

[0022] 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 speed of the high-speed disperser to 1500r / min, stir and disperse for 10 minutes to obtain the second modified mixed liquid.

[0023] Step 4: Add the second modified mixed liquid to 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 of more than 10 μm; then pass it through the centrifugal device 1 of the silver powder cleaning device to perform a solid-liquid separation, ethanol cleaning and a second solid-liquid separation in sequence, and dry the wet powder to obtain modified silver powder.

[0024] The surface modifier A is stearic acid, and the mass of the surface modifier A is 0.5% of the silver powder to be modified.

[0025] The surface modifier B is oleylamine, and the mass of the surface modifier B is 0.5% of the silver powder to be modified.

[0026] The mass of the ethanol used for dispersion is 100% of the silver powder to be modified.

[0027] like Figure 1-Figure 5 As shown, the silver powder cleaning device includes a centrifugal device 1, a filtering device 2, a vacuum filtration pump 3 and a driving device 4.

[0028] like Figure 1-Figure 5 As shown, 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 filtration 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.

[0029] like Figure 1-Figure 5 As shown, the centrifugal device 1 includes a cylinder 1 5 , a cylinder 2 6 and a scraping assembly 7 .

[0030] like Figure 1-Figure 5 As shown, a feed hole 8 is opened at the top of the cylinder 5, and one side of the scraper assembly 7 is fixedly connected to the top of the cylinder 5 through three fixing rods 9 in the feed hole 8.

[0031] like Figure 1-Figure 5 As shown, the top of the cylinder 2 6 is open, and a plurality of arc-shaped filter plates 10 are provided on the side of the cylinder 2 6 . The cylinder 2 6 rotates and moves up and down in the cylinder 1 5 , and the side of the scraping assembly 7 away from the feed hole 8 is connected to the bottom of the cylinder 2 6 .

[0032] like Figure 1-Figure 5 As shown, the scraping assembly 7 includes a fixed ring 11, a sliding sleeve rod 12, two push rods 13, two push rods 2 14, two push rods 3 15, two scrapers 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.

[0033] like Figure 1-Figure 5As shown, the fixed ring 11 is rotatably connected to the center position of the bottom of the cylinder body 2 6, the sliding rod of the sliding sleeve rod 12 passes through the fixed ring 11 and is fixedly connected to the bottom of the cylinder body 2 6, the rod sleeve of the sliding sleeve rod 12 is fixedly connected to the top of the cylinder body 5 in the feed hole 8 through three fixed rods 9, one side of the two push rods 13 is respectively hinged to the fixed ring 11, the two push rods 2 14 are respectively hinged to the side of the rod sleeve of the sliding sleeve rod 12 close to the fixed ring 11, the side of the two push rods 13 away from the fixed ring 11 is respectively hinged to the middle position of the two push rods 2 14, the side of the two push rods 2 14 away from the sliding sleeve rod 12 is respectively hinged to the scraper 16, and the push rod 3 15 is respectively hinged to the rod sleeve of the sliding sleeve rod 12 and the scraper 16 above the push rod 2 14.

[0034] like Figure 1-Figure 5 As shown, the side of push rod 2 14 and push rod 3 15 away from sliding sleeve rod 12 is fixedly connected to the stirring rod 17, and the upper and lower sides of the scraper 16 are provided with rotation grooves 18. Push rod 2 14 and push rod 3 15 respectively drive the stirring rod 17 to rotate in the rotation groove 18.

[0035] like Figure 1-Figure 5 As shown, the filter device 2 includes a filter cylinder 19, a sieve plate 20 and a feed pipe 21; like Figure 1-Figure 5 As shown, the feed pipe 21 is fixedly connected to the top of the cylinder 5, the feed pipe 21 is connected to the cylinder 5 through the feed hole 8, the side of the feed pipe 21 away from the cylinder 5 is connected to the filter cylinder 19, and the sieve plate 20 is fixedly connected inside the filter cylinder 19.

[0036] like Figure 1-Figure 5 As shown, the vacuum filtration pump 3 is connected to the cylinder 5 through the suction pipe 22.

[0037] like Figure 1-Figure 5 As shown, the driving device 4 includes a driving motor 1 23 , a sprocket 1 24 , a sprocket 25 , an L-shaped support frame 26 , a driving motor 27 , a gear 28 and a sliding sleeve rod 29 .

[0038] like Figure 1-Figure 5As shown, the driving motor 1 23 is fixedly connected to the side of the cylinder 1 5, the lower part of the driving motor 1 23 is drivingly connected to the sprocket 1 24, the bottom of the sprocket 25 is rotatably connected to the circular base 37 provided on the support frame 36, the sprocket 1 24 and the sprocket 25 are driven by the chain 30, the L-shaped support frame 26 is fixedly connected to the top of the sprocket 25, the driving motor 27, the gear 28 and the sliding rod of the sliding sleeve rod 29 are all fixedly connected to the L-shaped support frame 26, the rod sleeve of the sliding sleeve rod 29 is close to the side of the sprocket 25 and is meshed with the gear 28, the output shaft of the driving motor 27 drives the gear 28 to rotate, the rod sleeve of the sliding sleeve rod 29 is away from the sprocket 25 and passes through the cylinder 1 5 and is fixedly connected to the bottom of the cylinder 2 6, and the rod sleeve of the sliding sleeve rod 29 is slidably and rotatably connected to the cylinder 1 5.

[0039] like Figure 1-Figure 5 As shown, the sliding rod of the sliding sleeve rod 29 is provided with a limiting groove 31, and the rod sleeve of the sliding sleeve rod 29 is provided with a limiting structure 32. 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 sliding rod and the rod sleeve of the sliding sleeve rod 2.

[0040] like Figure 1-Figure 5 As shown, a liquid inlet 33 is provided on the side of the cylinder 5 away from the exhaust pipe 22, and a control valve 34 is provided on the liquid inlet 33; a liquid outlet 35 is provided at the lower part of the side of the cylinder 5, and a control valve 34 is provided on the liquid outlet 35.

[0041] The working principle of the silver powder cleaning device is as follows: Filtration: Turn on the vacuum filtration pump 3, and then add the second modified mixed liquid into the filter cylinder 19. As the pressure in the cylinder 5 decreases, the second modified mixed liquid is accelerated to pass through the sieve plate 20, and the silver powder particles with a particle size of more than 10μm are removed.

[0042] Solid-liquid separation: The second modified mixed liquid after filtration passes through the feeding pipe 21 and the feeding hole 8 in turn and enters the barrel 2 6; the driving motor 27 is started, and the driving motor 27 drives the rod sleeve of the sliding sleeve rod 29 to rise through the gear 28, so that the barrel 2 6 rises in the barrel 1 5, and the fixed ring 11 moves upward, and the push rod 14 is pushed perpendicular to the sliding sleeve rod 12 through the push rod 13, and the scraper 16 is close to the inner wall of the barrel 2 6. The driving motor 1 23 is turned on, and the sprocket 2 25 is driven to rotate through the sprocket 1 24, thereby driving the L-shaped support frame 26, the sliding sleeve rod 29 and the barrel 2 6 to rotate, and the barrel 2 6 and the scraper 16 rotate relatively, and the barrel 2 6 performs solid-liquid separation on the second modified mixed liquid, and the scraper 16 scrapes off the silver powder on the inner wall of the barrel 2 6 during the solid-liquid separation, and the liquid enters the barrel 1 5 and is discharged from the silver powder cleaning device through the liquid outlet 35.

[0043] Ethanol cleaning: close the liquid outlet 35, start the driving motor 27 again, the driving motor 27 drives the rod sleeve of the sliding sleeve rod 29 to descend through the gear 28, so that the cylinder 2 6 descends in the cylinder 1 5; at the same time, the fixed ring 11 moves downward, and the push rod 2 14 is pulled by the push rod 1 13 to form an angle with the sliding sleeve rod 12, and the push rod 2 14 and the push rod 3 15 both drive the stirring rod 17 to rotate, and the stirring rod 17 forms an angle with the scraper 16; ethanol is added into the cylinder 1 5 from the liquid inlet 33, and the ethanol flows in the cylinder 1 5 and the cylinder 2 6 through the arc filter plate 10. The rotation of the cylinder 2 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.

[0044] Example 2 The difference between this embodiment and embodiment 1 is that: Step 2: Add the silver powder to be modified into a high-speed mixer, then add the surface modifier A, control the speed of the high-speed mixer to 1400r / min, mix for 15min, and complete the 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 speed of the high-speed disperser to 1200r / min, stir and disperse for 18min, and obtain the second modified mixed solution; The surface modifier A is palmitic acid, and the mass of the surface modifier A is 1% of the silver powder to be modified; The surface modifier B is decylamine, and the mass of the surface modifier B is 0.8% of the silver powder to be modified; The mass of the ethanol used for dispersion is 60% of the silver powder to be modified.

[0045] Example 3 The difference between this embodiment and embodiment 1 is that: Step 2: Add the silver powder to be modified into a high-speed mixer, then add the surface modifier A, control the speed of the high-speed mixer to 1500r / min, mix for 10min, and complete the 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 speed of the high-speed disperser to 1000r / min, stir and disperse for 20min, and obtain the second modified mixed solution; The surface modifier A is silver stearate or silver octanoate, and the mass of the surface modifier A is 0.8% of the silver powder to be modified; The surface modifier B is octadecylamine, and the mass of the surface modifier B is 0.5% of the silver powder to be modified; The mass of the ethanol used for dispersion is 50% of the silver powder to be modified.

[0046] Example 4 The difference between this embodiment and embodiment 1 is that the surface modifier B is hexadecylamine.

[0047] Performance Testing The particle size distribution, bulk density, tap density, specific surface area, ignition loss and water contact angle of the silver powder to be modified and the modified silver powder prepared in Examples 1 to 3 were tested. The test results are shown in Table 1.

[0048] Table 1 It can be concluded from Table 1 that compared with the silver powder to be modified, the ignition loss of the modified silver powder only increased by 0.011% to 0.02%, the hydrophilicity was changed to completely hydrophobicity, the particle size distribution was narrower, and the tap density was higher.

[0049] The above description is only a preferred embodiment of the present invention and does not limit the present invention in other forms. Any technician familiar with the profession may use the technical content disclosed above to change or modify it into an equivalent embodiment with equivalent changes for application in other fields. However, any simple modification or equivalent change made to the above embodiment based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A method for post-treatment of composite modification of silver powder, characterized in that: The following steps are involved: Step 1: Add 350kg of 6% polyvinyl pyrrolidone aqueous solution into the reaction container. Start stirring, then add 1kg of nano silver seed crystals, and add 340kg of 20% silver nitrate aqueous solution and 315kg of 12% vitamin C aqueous solution simultaneously at a uniform speed, and the adding time is controlled within 20min. After sedimentation and solid-liquid separation, wash twice with deionized water, wash three times with anhydrous ethanol, and 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 the surface modifier A, control the speed of the high-speed mixer to 1200-1500 r / min, mix for 3-20 minutes, and complete the 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 speed of the high-speed disperser to 1000-1500r / min, stir and disperse for 5-20min, and obtain the second modified mixed solution; Step 4: Add the second modified mixed liquid to the silver powder cleaning device, first filter it through the filtering device (2) of the silver powder cleaning device to remove silver powder particles with a particle size of more than 10 μm; then pass it through the centrifugal device (1) of the silver powder cleaning device to perform a solid-liquid separation, ethanol cleaning and a second solid-liquid separation in sequence, and dry the wet powder to obtain modified silver powder.

2. The silver powder composite modification post-treatment method according to claim 1, characterized in that: 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% to 1% of the silver powder to be modified; The surface modifier B is at least one of octadecylamine, oleylamine, decylamine and hexadecylamine, and the mass of the surface modifier B is 0.1% to 1% of the silver powder to be modified; The mass of the dispersing ethanol is 50% to 100% of the silver powder to be modified.

3. The silver powder composite modification post-treatment method according to claim 1, characterized in that: The silver powder cleaning device comprises a centrifugal device (1), a filtering device (2), a vacuum filtration pump (3) and a driving device (4); The centrifugal device (1) is placed on the ground via a support frame (36); the filtering device (2) is fixedly connected to the top of the centrifugal device (1); and the vacuum filtration 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.

4. The silver powder composite modification post-treatment method according to claim 3, characterized in that: The centrifugal device (1) comprises a cylinder body 1 (5), a cylinder body 2 (6) and a scraping assembly (7); A feed hole (8) is provided at the top of the cylinder body 1 (5), and one side of the scraper assembly (7) is fixedly connected to the top of the cylinder body 1 (5) via 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 scraping assembly (7) is connected to the bottom of the second cylinder (6) on the side away from the feed hole (8).

5. The silver powder composite modification post-treatment method according to claim 4, characterized in that: The scraping assembly (7) comprises a fixed ring (11), a sliding sleeve rod 1 (12), two push rods 1 (13), two push rods 2 (14), two push rods 3 (15), two scrapers (16) and four stirring rods (17); the sliding rod and the rod sleeve of the sliding sleeve rod 1 (12) rotate and slide relative to each other; The fixed ring (11) is rotatably connected to the center position of the bottom of the second cylinder (6); the sliding rod of the sliding sleeve rod (12) passes through the fixed ring (11) and is fixedly connected to the bottom of the second cylinder (6); the rod sleeve of the sliding sleeve rod (12) is fixedly connected to the top of the first cylinder (5) in the feed hole (8) through three fixed rods (9); one side of the two push rods (13) is respectively hinged to the fixed ring (11); and the two push rods (14) are respectively hinged to the fixed ring (11). On the side of the rod sleeve of the sliding sleeve rod 1 (12) close to the fixed ring (11), the sides of the two push rods 1 (13) away from the fixed ring (11) are respectively hinged to the middle position of the two push rods 2 (14), the sides of the two push rods 2 (14) away from the sliding sleeve rod 1 (12) are respectively hinged to the scraper (16), and the push rod 3 (15) is respectively hinged to the rod sleeve of the sliding sleeve rod 1 (12) and the scraper (16) above the push rod 2 (14); The push rod 2 (14) and the push rod 3 (15) are fixedly connected to the stirring rod (17) at the side away from the sliding sleeve rod 1 (12), and the scraper (16) is provided with a rotation groove (18) on the upper and lower sides. The push rod 2 (14) and the push rod 3 (15) respectively drive the stirring rod (17) to rotate in the rotation groove (18).

6. The silver powder composite modification post-treatment method according to claim 5, characterized in that: The filtering device (2) comprises a filtering cylinder (19), a sieve plate (20) and a feed pipe (21); The feed pipe (21) is fixedly connected to the top of the barrel (5), the feed pipe (21) is connected to the barrel (5) through the feed hole (8), the side of the feed pipe (21) away from the barrel (5) is connected to the filter barrel (19), and the sieve plate (20) is fixedly connected inside the filter barrel (19).

7. The silver powder composite modification post-treatment method according to claim 6, characterized in that: The vacuum filtration pump (3) is connected to the cylinder body (5) via an air extraction pipe (22).

8. The silver powder composite modification post-treatment method according to claim 7, characterized in that: The driving device (4) comprises a driving motor 1 (23), a sprocket 1 (24), a sprocket 2 (25), an L-shaped support frame (26), a driving motor 2 (27), a gear (28) and a sliding sleeve rod 2 (29); The driving motor 1 (23) is fixedly connected to the side of the cylinder 1 (5); the lower part of the driving motor 1 (23) is drivingly connected to the sprocket 1 (24); the lower part of the sprocket 2 (25) is rotatably connected to a circular base (37) provided on the support frame (36); the sprocket 1 (24) and the sprocket 2 (25) are driven by a chain (30); the L-shaped support frame (26) is fixedly connected to the upper part of the sprocket 2 (25); the driving motor 2 (27), the gear (28) and the sliding sleeve rod 2 (29) are connected to the driving motor 2 (27), the gear (28) and the sliding sleeve rod 2 (29) ) are fixedly connected to the L-shaped support frame (26); the rod sleeve of the sliding sleeve rod 2 (29) is provided with teeth on the side close to the sprocket wheel 2 (25) and meshing with the gear (28); the output shaft of the driving motor 2 (27) drives the gear (28) to rotate; the rod sleeve of the sliding sleeve rod 2 (29) is away from the sprocket wheel 2 (25) and passes through the cylinder body 1 (5) and is fixedly connected to the bottom of the cylinder body 2 (6); the rod sleeve of the sliding sleeve rod 2 (29) is connected to the cylinder body 1 (5) in a sliding and rotational manner.

9. The silver powder composite modification post-treatment method according to claim 8, characterized in that: The sliding rod of the sliding sleeve rod 2 (29) is provided with a limiting groove (31), and the rod sleeve of the sliding sleeve rod 2 (29) is provided with a limiting structure (32). 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 sliding rod and the rod sleeve of the sliding sleeve rod 2.

10. The silver powder composite modification post-treatment method according to claim 9, characterized in that: The cylinder body 1 (5) is provided with a liquid inlet (33) on a side 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 at a lower portion of a side surface of the cylinder body 1 (5), and the control valve (34) is provided on the liquid outlet (35).

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