A preparation device and preparation method of high sintering activity porous silver powder

Abstract

The present invention discloses a preparation device and method for porous silver powder with high sintering activity. The preparation device includes: a set of raw material preparation devices and a continuous mixing and reaction device; the continuous mixing and reaction device includes: a primary mixing chamber, the upper end of which is connected to the discharge end of the set of raw material preparation devices through a feed conduit and a parallel pump; a retractable pipe connected to the lower end of the feed conduit, the bottom side of which is sealed and rotatably mounted with a liquid distribution container, and the upper end of the liquid distribution container is evenly provided with a plurality of corresponding liquid discharge pipes; and a secondary mixing chamber, the upper end of which is connected to the lower end of the primary mixing chamber through a plurality of evenly distributed guide pipes, the discharge ends of the guide pipes being respectively threaded downwardly and movably connected to corresponding distribution pipes through spiral grooves. The present invention can achieve continuous preparation and processing of silver powder, so that the oxidizing liquid and the reducing liquid can be quickly mixed and fully reacted, thereby obtaining porous silver powder with high sintering activity.

Description

Technical Field

[0001] The present invention relates to the technical field of preparation and processing of porous silver powder with high sintering activity, and in particular to a preparation device and a preparation method of porous silver powder with high sintering activity. Background Art

[0002] Silver paste is widely used in semiconductor metallization, especially in silicon solar cells. Silver powder is the material with the highest content in silver paste. Its morphology and structure determine its properties, especially its sintering activity. With the development of the industry, the requirements for solar cell conversion efficiency are getting higher and higher. Currently, silicon solar cells generally use laser-assisted sintering technology (Laser-enhanced contact optimization, LECO) to improve the contact between the metal electrode and the silicon wafer in the solar cell, so that higher current can be obtained at the same line width, or thinner lines can be obtained at the same current, thereby improving the conversion efficiency of the solar cell. LECO requires silver powder to have higher sintering activity to match a larger sintering temperature window.

[0003] Due to limitations in processing equipment, the current silver powder preparation process often relies on batch reactors for the synthesis reaction, with the addition of large amounts of polyvinylpyrrolidone (PVP) as a surfactant to ensure the dispersion and uniformity of the silver powder. This not only results in low production efficiency, but also in coarse silver powder grains and high crystallinity, which reduces the sintering activity of the silver powder. Solar cells made with this silver powder have low switching voltages, high series resistance, and ultimately low photoelectric conversion efficiency.

[0004] Therefore, the purpose of the present invention is to design a preparation device and a preparation method for porous silver powder with high sintering activity that can realize the continuous preparation and processing of silver powder, so that the oxidizing liquid and the reducing liquid can be quickly mixed and fully reacted, thereby effectively improving the preparation efficiency of the product and obtaining porous silver powder with high sintering activity. Summary of the Invention

[0005] In response to the technical problems existing in the above-mentioned prior art, the present invention provides a preparation device and a preparation method of high sintering activity porous silver powder. The preparation device and the preparation method of high sintering activity porous silver powder can effectively solve the technical problems existing in the above-mentioned prior art.

[0006] The technical solution of the present invention is:

[0007] A preparation device for highly sintered porous silver powder comprises: a raw material preparation device and a continuous mixing reaction device, wherein the continuous mixing reaction device comprises:

[0008] A primary mixing chamber, the upper end of which is penetrated by a corresponding feed conduit, the upper end of which is connected in parallel to a discharge end of a group of raw material preparation devices;

[0009] A retractable tube is connected to the lower end of the feed conduit. A liquid distribution container connected to the retractable tube is rotatably mounted on the bottom side of the retractable tube. A plurality of corresponding liquid outlet pipes are evenly distributed in the radial direction of the liquid distribution container. The lengths of adjacent liquid outlet pipes are different. The liquid outlet ends of the liquid outlet pipes are respectively configured in a constricted shape and are horizontally folded backward in an arc shape.

[0010] The secondary mixing chamber has an upper end connected to the lower end of the primary mixing chamber through a number of evenly distributed guide pipes. The discharge ends of the guide pipes are respectively screwed downwardly and movable through spiral grooves to connect with corresponding distribution pipes. The discharge ends of the distribution pipes are respectively fixed with a circle of corresponding fixed convex edges, and a number of corresponding mounting grooves are respectively provided on the fixed convex edges. Corresponding stirring rods are respectively swingably installed in the mounting grooves. Coil springs sleeved on the outer periphery of the distribution pipes are respectively fixed between the fixed convex edges and the guide pipes.

[0011] The raw material preparation devices respectively include raw material preparation tanks, in which stirring shafts driven by corresponding drive motors are rotatably installed, and the middle part of the stirring shaft can swing up and down and is equipped with a group of corresponding first stirring plates, the end of the first stirring plate not connected to the stirring shaft is tilted downward, and the middle part of the first stirring plate is tilted upward and fixedly connected to the corresponding second stirring plate, the upper end of the second stirring plate can swing back and forth and is equipped with corresponding third stirring plates, and corresponding buffer springs are respectively fixed between the third stirring plate and the corresponding second stirring plate.

[0012] The upper portion of the raw material preparation tank is respectively provided with corresponding feeding ports, and the bottom of the raw material preparation tank is respectively provided with corresponding discharge pipes. The upper end of the feed conduit is connected to the discharge end of the discharge pipe in parallel with a pump.

[0013] The retractable tube is a metal bellows, and the liquid distribution container includes a barrel-shaped distribution container body. The upper end of the distribution container body is connected inward in a stepped manner to a circle of connecting sleeves with a diameter smaller than the distribution container body. The connecting sleeve is rotatably installed on the bottom side of the retractable tube through a sealed bearing.

[0014] A pressure slope surface having the same rotation direction as the spiral groove is provided on the outer side of one end of the stirring rod not mounted on the fixed convex edge; a push slope surface having the same rotation direction as the spiral groove is provided on the inner side of the other end of the stirring rod not mounted on the fixed convex edge.

[0015] A method for preparing porous silver powder with high sintering activity, based on the above-mentioned equipment for preparing porous silver powder with high sintering activity, comprises the following specific steps:

[0016] S1, adding silver nitrate and an aqueous solution into a raw material preparation tank of a raw material preparation device, stirring to dissolve the silver nitrate in the aqueous solution to form a silver nitrate solution, then adding ammonia water, stirring evenly to form a silver ammonia solution;

[0017] S2, adding the reducing agent and the aqueous solution into a raw material preparation tank of another raw material preparation device, stirring to dissolve the reducing agent in the aqueous solution, then adding surfactant A and surfactant B, and stirring evenly to form a reducing agent solution;

[0018] S3, mixing the silver ammonia solution and the reducing agent solution in proportion by pumping and transporting them through the primary mixing chamber and the secondary mixing chamber of the continuous mixing reaction device for continuous mixing reaction, and collecting the highly sintered active porous silver powder obtained by the reaction after being output from the secondary mixing chamber.

[0019] The concentration of the silver nitrate solution in step S1 is 0.05-0.3 mol / L, and the molar ratio of ammonia water to silver nitrate is 2:1-3:1.

[0020] The concentration of the reducing agent in step S2 is 0.075-0.45 mol / L, the concentration of surfactant A is 0.2-2%, and the concentration of surfactant B is 1-5%.

[0021] The reducing agent is one or two of ascorbic acid, formaldehyde, glucose and hydrogen peroxide.

[0022] The surfactant A is one of isododecyl alcohol, isotetradecyl alcohol, and isohexadecanol; the surfactant B is one of hexadecyltrimethylammonium bromide, sodium lauryl sulfate, dodecyldimethylbetaine, and sodium laurylaminopropionate.

[0023] Advantages of the present invention:

[0024] 1) When preparing silver powder, the present invention uses a set of raw material preparation devices to separately prepare an oxidizing liquid (silver ammonia solution) and a reducing liquid (reducing agent solution). The prepared oxidizing liquid and reducing liquid are then pumped into a feed conduit and then discharged through a liquid outlet pipe in the radial direction of a liquid distribution container. Since the liquid outlet ends of the liquid outlet pipes are respectively configured in a constricted shape and horizontally folded backward in an arc shape, the oxidizing liquid and reducing liquid can form a horizontal forward thrust during the process of being discharged into the primary mixing chamber, thereby driving the liquid distribution container to rotate and agitate the material in the primary mixing chamber. The flushing force generated by the material ejected from different positions can also significantly enhance the agitation effect of the material in the primary mixing chamber, thereby achieving continuous preparation of silver powder, greatly improving production capacity, and thus solving the problems of limited single-batch production of traditional intermittent reactors and unstable quality during scale-up and expansion.

[0025] 2) The drive and distribution container of the present invention is connected to the feed conduit via a retractable tubing. Therefore, the material flow pressure can be controlled by controlling the pumping volume of the oxidizing and reducing liquids. When the material flow pressure increases, the retractable tubing extends under pressure, causing the distribution container to move downward and its rotational speed to increase. When the material flow pressure decreases, the retractable tubing retracts, causing the distribution container to move upward and its rotational speed to decrease. This effectively drives the distribution container up and down during rotation, and regulates its speed, further ensuring the mixing of the materials entering the primary mixing chamber, thereby further achieving continuous production of silver powder.

[0026] 3) Based on the primary mixing chamber, the present invention further provides a secondary mixing chamber, the upper end of which is connected to the lower end of the primary mixing chamber via a number of evenly spaced guide tubes. The discharge ends of the guide tubes are each threaded downwardly and movable through a spiral groove to be screwed to a corresponding distribution tube. The discharge ends of the distribution tubes are each fixedly connected to a circle of fixed ridges, on which stirring rods are swingably mounted, and between the fixed ridges and the guide tubes are each fixedly connected a coil spring sleeved around the outer periphery of the distribution tube. When the material flow pressure in the primary mixing chamber increases, the pressure of the material flowing through the distribution tube also increases. At this time, the distribution tube spirals downward under pressure, and the coil spring is stretched and wound. When the material flow pressure in the primary mixing chamber decreases, the pressure of the material flowing through the distribution tube also decreases. At this time, the distribution tube rotates upward and resets under the drive of the coil spring, thereby driving the stirring rod to rotate at different heights to ensure the mixing effect of the material entering the secondary mixing chamber, thereby further achieving continuous preparation of silver powder.

[0027] 4) When the material flow pressure increases, the distribution pipe is compressed and spirals downward, which requires tensile and winding forces to be generated on the coil spring. At this time, if it is also necessary to provide the stirring rod with a mixing force on the material, it is difficult to achieve. For this reason, the stirring rod of the present invention is provided with a pressure slope surface with a rotation direction consistent with the spiral groove on the outer side of the end not mounted on the fixed ridge, so that when the distribution pipe spirals downward, the stirring rod is pushed inward by the material and does not swing downward, thereby reducing the resistance of the distribution pipe when it spirals downward, thereby ensuring the practical effect of the present invention.

[0028] 5) The inner side of the other end of the stirring rod of the present invention that is not mounted on the fixed convex edge is provided with a push-blocking slope surface with a rotation direction consistent with the spiral groove, so that when the distribution pipe rotates upward and resets under the drive of the spiral spring, the stirring rod can be pushed downward by the external thrust formed by the material, so as to ensure that the stirring rod can form a mixing effect on the material during the upward rotation of the distribution pipe, thereby further ensuring the practical effect of the present invention.

[0029] 6) The product of this invention, under the combined action of multiple surfactants, forms submicron and nanoscale bubbles, providing a soft template and imparting a porous structure to the synthesized spherical silver powder. This, in turn, impedes Ostwald ripening, reducing the silver particle size, while further increasing the specific surface area and enhancing its sintering activity. Testing has shown that the silver powder produced by this method has a reduced grain size of 21 nm, a reduced series resistance of 0.002 Ω, and an increased conversion efficiency of 21%. Furthermore, comparison of SEM images clearly demonstrates a significant increase in the porosity and sintering activity of the silver powder produced by this method.

[0030] 7) The raw material preparation device of the present invention includes a raw material preparation tank, wherein the middle part of the stirring shaft provided in the raw material preparation tank can swing up and down and is installed with a group of first stirring plates, the end of the first stirring plate not connected to the stirring shaft is tilted downward, and the middle part of the first stirring plate is tilted upward and fixed with a second stirring plate, and the upper end of the second stirring plate can swing back and forth and is respectively installed with a third stirring plate, and a buffer spring is respectively fixed between the third stirring plate and the second stirring plate. During the raw material preparation process, the mixing effect can be improved by controlling the driving speed of the stirring shaft. When the speed of the stirring shaft increases, the pressure on the third stirring plate increases and it swings backward, thereby forming a force slope to drive the second stirring plate and the first stirring plate to swing upward as a whole; and when the speed of the stirring shaft decreases, the third stirring plate is reset under the action of the buffer spring, and the second stirring plate and the first stirring plate are lowered to their original height as a whole. In this way, the mixing effect in the raw material preparation process can be effectively improved by controlling the driving speed of the stirring shaft, thereby further improving the use effect of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a structural schematic diagram of the present invention.

[0032] Figure 2 It is a cross-sectional view of the raw material preparation device.

[0033] Figure 3 It is a schematic diagram of the assembly of the stirring shaft, the first stirring plate, the second stirring plate and the third stirring plate.

[0034] Figure 4 It is a cross-sectional view of a continuous mixing reaction device.

[0035] Figure 5 This is a schematic diagram of the assembly of the liquid distribution container, retractable tube, and feed conduit.

[0036] Figure 6 This is a structural diagram of a material distribution pipe with a stirring rod installed through a fixed convex edge.

[0037] Figure 7 This is a SEM electron microscope image of the silver powder prepared in the present invention.

[0038] In the accompanying drawings: raw material preparation device 1, raw material preparation tank 101, drive motor 102, stirring shaft 103, first stirring plate 104, second stirring plate 105, third stirring plate 106, buffer spring 107, continuous mixing reaction device 2, primary mixing chamber 201, feed conduit 202, retractable tube 203, liquid distribution container 204, distribution container body 2041, connecting sleeve 2042, liquid outlet pipe 205, secondary mixing chamber 206, guide pipe 207, distribution pipe 208, stirring rod 209, coil spring 2010, fixed ridge 3, mounting groove 301, feeding port 4, discharge pipe 5, sealing bearing 6, pressure slope 7, push slope 8. DETAILED DESCRIPTION

[0039] In order to facilitate understanding by those skilled in the art, the structure of the present invention is further described in detail with reference to the embodiments and the accompanying drawings:

[0040] Example 1:

[0041] refer to Figure 1-6 A device for preparing porous silver powder with high sintering activity comprises: a raw material preparation device 1 and a continuous mixing reaction device 2, wherein the continuous mixing reaction device 2 comprises:

[0042] A primary mixing chamber 201 is provided with a corresponding feed conduit 202 at its upper end, and the upper end of the feed conduit 202 is connected to a discharge end of a group of the raw material preparation devices 1 in parallel with a pump;

[0043] A retractable tube 203 is connected to the lower end of the feed conduit 202. A liquid distribution container 204 connected to the retractable tube 203 is rotatably mounted on the bottom side of the retractable tube 203. The liquid distribution container 204 is evenly distributed in the radial direction with a plurality of corresponding liquid outlet pipes 205. The lengths of adjacent liquid outlet pipes 205 are different, and the liquid outlet ends of the liquid outlet pipes 205 are respectively configured in a constricted shape and horizontally folded backward in an arc shape.

[0044] The upper end of the secondary mixing chamber 206 is connected to the lower end of the primary mixing chamber 201 through a number of evenly distributed guide tubes 207. The discharge ends of the guide tubes 207 are respectively screwed downwardly and movable through spiral grooves to connect with corresponding distribution tubes 208. The discharge ends of the distribution tubes 208 are respectively fixed with a circle of corresponding fixed ridges 3. The fixed ridges 3 are respectively provided with a number of corresponding mounting grooves 301. The corresponding stirring rods 209 are respectively swingably mounted in the mounting grooves 301. The fixed ridges 3 and the guide tubes 207 are respectively fixed with coil springs 2010 sleeved on the outer periphery of the distribution tube 208.

[0045] During the preparation of silver powder according to the present invention, an oxidizing liquid (silver ammonia solution) and a reducing liquid (reducing agent solution) are separately prepared by a set of raw material preparation devices 1. The prepared oxidizing and reducing liquids are then pumped into a feed conduit 202 and discharged through a liquid outlet pipe 205 radially disposed in a liquid distribution container 204. Because the outlet ends of the liquid outlet pipe 205 are each configured in a constricted shape and horizontally folded backward in an arc shape, the oxidizing and reducing liquids generate a horizontal forward thrust during their delivery into the primary mixing chamber 201, thereby driving the liquid distribution container 204 to rotate and agitate the material within the primary mixing chamber 201. Furthermore, the flushing force generated by the material ejected from different positions significantly enhances the agitation of the material within the primary mixing chamber 201, thereby achieving continuous production of silver powder and significantly increasing production capacity. This, in turn, addresses the problems of limited single-batch production in conventional batch reactors and unstable quality during scale-up and expansion.

[0046] Furthermore, the drive liquid distribution container 204 of the present invention is connected to the feed conduit 202 via a retractable tube 203. Therefore, the pumping volume of the oxidizing and reducing liquids can be controlled to control the material flow pressure. When the material flow pressure increases, the retractable tube 203 is compressed and extends, causing the liquid distribution container 204 to move downward and increase its rotational speed. When the material flow pressure decreases, the retractable tube 203 retracts, causing the liquid distribution container 204 to move upward and decrease its rotational speed. This effectively drives the liquid distribution container 204 upward and adjusts its speed during rotation, further ensuring the mixing effect of the materials entering the primary mixing chamber 201, thereby further achieving continuous production of silver powder.

[0047] On the basis of the primary mixing chamber 201, the present invention further adds a secondary mixing chamber 206, the upper end of which is connected to the lower end of the primary mixing chamber 201 through a number of evenly distributed guide tubes 207, the discharge ends of the guide tubes 207 are respectively screwed downwardly and movable through spiral grooves to be connected with corresponding distribution tubes 208, the discharge ends of the distribution tubes 208 are respectively fixedly connected with a circle of fixed ridges 3, on which stirring rods 209 are respectively swingably installed, and between the fixed ridges 3 and the guide tubes 207 are respectively fixedly connected coil springs 2010 sleeved on the outer periphery of the distribution tubes. When the material flow pressure in the primary mixing chamber 201 increases, the material pressure flowing through the distribution tube 208 will also increase. At this time, the distribution tube 208 spirals downward after being pressurized, and the coil spring 2010 is stretched and wound. When the material flow pressure in the primary mixing chamber 201 decreases, the material pressure flowing through the distribution tube 208 will also decrease. At this time, the distribution tube 208 rotates upward and resets under the drive of the coil spring 2010, thereby driving the stirring rod 209 to rotate at different heights to ensure the mixing effect of the material entering the secondary mixing chamber 206, thereby further realizing the continuous preparation of silver powder.

[0048] The raw material preparation device 1 includes a raw material preparation tank 101, in which a stirring shaft 103 driven by a corresponding drive motor 102 is rotatably installed. The middle part of the stirring shaft 103 can swing up and down and is installed with a group of corresponding first stirring plates 104. The end of the first stirring plate 104 that is not connected to the stirring shaft 103 is tilted downward, and the middle part of the first stirring plate 104 is tilted upward and fixed with a corresponding second stirring plate 105. The upper end of the second stirring plate 105 can swing back and forth and is installed with a corresponding third stirring plate 106. Corresponding buffer springs 107 are fixed between the third stirring plate 106 and the corresponding second stirring plate 105.

[0049] During the raw material preparation process, the mixing effect can be improved by controlling the driving speed of the stirring shaft 103. When the speed of the stirring shaft 103 increases, the third stirring plate 106 is subjected to increased pressure and swings backward, thereby forming a force-bearing slope, which drives the second stirring plate 105 and the first stirring plate 104 to swing upward as a whole. When the speed of the stirring shaft 103 decreases, the third stirring plate 106 is reset under the action of the buffer spring 107, and the second stirring plate 105 and the first stirring plate 104 are lowered to their original height. In this way, the mixing effect during the raw material preparation process can be effectively improved by controlling the driving speed of the stirring shaft 103, thereby further improving the use effect of the present invention.

[0050] The upper portion of the raw material preparation tank 101 is provided with corresponding feeding ports 4 , and the bottom of the raw material preparation tank 101 is provided with corresponding discharge pipes 5 . The upper end of the feed conduit 202 is connected to the discharge end of the discharge pipe 5 in parallel with a pump.

[0051] The retractable tube 203 adopts a metal bellows, and the liquid distribution container 204 includes a barrel-shaped distribution container body 2041. The upper end of the distribution container body 2041 is connected inward in a stepped manner with a connecting sleeve 2042 having a diameter smaller than that of the distribution container body 2041. The connecting sleeve 2042 is rotatably installed on the bottom side of the retractable tube 203 through a sealing bearing 6.

[0052] A pressure slope 7 having a rotation direction consistent with the spiral groove is provided on the outer side of one end of the stirring rod 209 not installed on the fixed protrusion 2; a push slope 8 having a rotation direction consistent with the spiral groove is provided on the inner side of the other end of the stirring rod 209 not installed on the fixed protrusion 3.

[0053] When the material flow pressure increases, the distribution pipe 208 is compressed and spirals downward, requiring a pulling and winding force to be applied to the coil spring 1010. At this point, if the stirring rod 209 is also required to provide a mixing force on the material, this is difficult to achieve. To this end, the stirring rod 209 of the present invention is provided with a pressure-bearing slope 7 on the outer side of the end not mounted on the fixed flange 3, with a rotation direction consistent with the spiral groove. This ensures that when the distribution pipe 208 spirals downward, the stirring rod 209 is pushed inward by the material and does not swing downward, thereby reducing the resistance of the distribution pipe 208 during its spiral downward movement and ensuring the practical effect of the present invention. Furthermore, when the distribution pipe 208 rotates upward and returns to its original position under the drive of the coil spring 2010, the thrust-blocking slope 8 of the stirring rod 209 is pushed outward by the material and swings downward, ensuring that the stirring rod 209 can achieve a mixing effect on the material during the upward rotation of the distribution pipe 208, further ensuring the practical effect of the present invention.

[0054] Example 2:

[0055] A method for preparing porous silver powder with high sintering activity, based on the equipment for preparing porous silver powder with high sintering activity described in the first embodiment, comprises the following specific steps:

[0056] S1, adding silver nitrate and an aqueous solution into a raw material preparation tank 101 of a raw material preparation device 1, stirring to dissolve the silver nitrate in the aqueous solution to form a silver nitrate solution, then adding ammonia water, and stirring evenly to form a silver ammonia solution, wherein the concentration of the silver nitrate solution is 0.15 mol / L, and the molar ratio of ammonia water to silver nitrate is 2.5:1;

[0057] S2, adding a reducing agent and an aqueous solution into a raw material preparation tank 101 of another raw material preparation device 1, stirring to dissolve the reducing agent in the aqueous solution, then adding surfactant A and surfactant B, stirring evenly to form a reducing agent solution, wherein the concentration of the reducing agent is 0.25 mol / L, the concentration of surfactant A is 0.15%, and the concentration of surfactant B is 3.5%;

[0058] S3, the silver ammonia solution and the reducing agent solution are mixed in a ratio of 1:1 and transported through the primary mixing chamber 201 and the secondary mixing chamber 206 of the continuous mixing reaction device 2 by pumping for continuous mixing reaction, and the highly sintered active porous silver powder obtained by the reaction is output from the secondary mixing chamber 206 and collected.

[0059] The reducing agent is ascorbic acid and formaldehyde. The surfactant A is isohexadecanol; and the surfactant B is dodecyl dimethyl betaine.

[0060] The product of the present invention forms submicron and nanometer-scale bubbles under the combined action of multiple surfactants, providing a soft template, so that the synthesized spherical silver powder has a porous structure inside, thereby affecting Ostwald ripening, reducing the grain size of the silver particles, and further increasing the specific surface area of ​​the silver powder and its sintering activity. Testing has shown that the silver powder prepared by the preparation method of the present invention has a grain size reduced to 21nm, a series resistance reduced to 0.002Ω, and a conversion efficiency increased to 21%. Figure 7 According to the SEM electron microscope image, it can be seen that the porosity of the silver powder prepared by the preparation method of the present invention is significantly improved, and the sintering activity of the silver powder is improved.

[0061] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A device for preparing highly sintered porous silver powder, comprising: A set of raw material preparation device (1) and continuous mixing reaction device (2), characterized in that the continuous mixing reaction device (2) comprises: A primary mixing chamber (201) is provided with a corresponding feed conduit (202) at its upper end, and the upper end of the feed conduit (202) is connected in parallel to a discharge end of a group of the raw material preparation devices (1); A retractable tube (203) is connected to the lower end of the feed conduit (202); a liquid distribution container (204) connected to the retractable tube (203) is rotatably mounted on the bottom side of the retractable tube (203); a plurality of corresponding liquid outlet pipes (205) are evenly distributed in the radial direction of the liquid distribution container (204); the lengths of two adjacent liquid outlet pipes (205) are different, and the liquid outlet ends of the liquid outlet pipes (205) are respectively configured in a constricted shape and horizontally folded backward in an arc shape; The secondary mixing chamber (206) has an upper end connected to the lower end of the primary mixing chamber (201) through a plurality of evenly distributed guide tubes (207), the discharge ends of the guide tubes (207) are respectively threaded downwardly and movable through spiral grooves to be connected to corresponding distribution tubes (208), the discharge ends of the distribution tubes (208) are respectively fixedly connected to a circle of corresponding fixed ridges (3), the fixed ridges (3) are respectively provided with a plurality of corresponding mounting grooves (301), the mounting grooves (301) are respectively swivellably mounted with corresponding stirring rods (209), and the fixed ridges (3) and the guide tubes (207) are respectively fixedly connected to spiral springs (2010) sleeved on the outer periphery of the distribution tubes (208).

2. The preparation equipment for highly sintered porous silver powder according to claim 1, characterized in that: The raw material preparation device (1) comprises a raw material preparation tank (101), wherein a stirring shaft (103) driven by a corresponding driving motor (102) is rotatably installed in the raw material preparation tank (101), and a group of corresponding first stirring plates (104) are installed in the middle part of the stirring shaft (103) so as to swing up and down. The end of the first stirring plate (104) not connected to the stirring shaft (103) is tilted downward, and the middle part of the first stirring plate (104) is tilted upward and fixedly connected to a corresponding second stirring plate (105). The upper end of the second stirring plate (105) is respectively mounted with a corresponding third stirring plate (106) so as to swing back and forth, and a corresponding buffer spring (107) is respectively fixedly connected between the third stirring plate (106) and the corresponding second stirring plate (105).

3. The preparation equipment of a highly sintered active porous silver powder according to claim 2, characterized in that: The upper portion of the raw material preparation tank (101) is provided with a corresponding feeding port (4), and the bottom portion of the raw material preparation tank (101) is provided with a corresponding discharge pipe (5). The upper end portion of the feed conduit (202) is connected to the discharge end of the discharge pipe (5) in parallel with a pump.

4. The preparation equipment for highly sintered porous silver powder according to claim 1, characterized in that: The retractable tube (203) is a metal bellows, and the liquid dispensing container (204) comprises a barrel-shaped dispensing container body (2041). The upper end of the dispensing container body (2041) is inwardly connected in a stepped manner to a connecting sleeve (2042) having a diameter smaller than that of the dispensing container body (2041). The connecting sleeve (2042) is rotatably mounted on the bottom side of the retractable tube (203) via a sealing bearing (6).

5. The preparation equipment of a highly sintered active porous silver powder according to claim 1, characterized in that: A pressure slope (7) having a rotation direction consistent with the spiral groove is provided on the outer side of one end of the stirring rod (209) not mounted on the fixed convex edge (3); and a push slope (8) having a rotation direction consistent with the spiral groove is provided on the inner side of the other end of the stirring rod (209) not mounted on the fixed convex edge (3).

6. A method for preparing porous silver powder with high sintering activity, based on the equipment for preparing porous silver powder with high sintering activity according to any one of claims 1 to 5, characterized in that: The following specific steps are included: S1, adding silver nitrate and an aqueous solution into a raw material preparation tank (101) of a raw material preparation device (1), stirring to dissolve the silver nitrate in the aqueous solution to form a silver nitrate solution, then adding ammonia water, stirring evenly to form a silver ammonia solution; S2, adding the reducing agent and the aqueous solution into a raw material preparation tank (101) of another raw material preparation device (1), stirring to dissolve the reducing agent in the aqueous solution, then adding surfactant A and surfactant B, stirring evenly to form a reducing agent solution; S3, mixing the silver ammonia solution and the reducing agent solution in proportion by pumping and transporting them through the primary mixing chamber (201) and the secondary mixing chamber (206) of the continuous mixing reaction device (2) for continuous mixing reaction, and collecting the highly sintered active porous silver powder obtained by the reaction after being discharged from the secondary mixing chamber (206).

7. The method for preparing a porous silver powder with high sintering activity according to claim 6, characterized in that: The concentration of the silver nitrate solution in step S1 is 0.05-0.3 mol / L, and the molar ratio of ammonia water to silver nitrate is 2:1-3:

1.

8. The method for preparing a porous silver powder with high sintering activity according to claim 7, characterized in that: The concentration of the reducing agent in step S2 is 0.075-0.45 mol / L, the concentration of surfactant A is 0.2-2%, and the concentration of surfactant B is 1-5%.

9. The method for preparing a porous silver powder with high sintering activity according to claim 8, characterized in that: The reducing agent is one or two of ascorbic acid, formaldehyde, glucose and hydrogen peroxide.

10. The method for preparing porous silver powder with high sintering activity according to claim 9, characterized in that: The surfactant A is one of isododecyl alcohol, isotetradecyl alcohol, and isohexadecanol; the surfactant B is one of hexadecyltrimethylammonium bromide, sodium lauryl sulfate, dodecyldimethylbetaine, and sodium laurylaminopropionate.

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