Method and device for preparing high-dispersion and wide-distribution silver powder

Abstract

The invention relates to the technical field of silver powder preparation, in particular to a high-dispersion and wide-distribution silver powder preparation method and device, and the preparation device comprises a guide rail, a flushing system, a drying oven and an ingredient mixing tank composed of an upper tank body and a movable lower seat body. The movable lower seat body can be separated from the upper tank body and can move to a flushing station below a flushing system for flushing and move to a heating station below a drying oven for drying in sequence along a guide rail, and a movable cleaning assembly is further connected to the guide rail; the movable cleaning assembly moves to the position under the upper tank body along the guide rail to wash the interior of the upper tank body. According to the invention, the proportioning of a silver-ammonia solution A, a dispersant solution B, a surfactant solution C and a reducing solution D can be completed at the same time through the proportioning and mixing tank consisting of the upper tank body and the movable lower seat body, so that the working efficiency is greatly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of silver powder preparation, and in particular to a method and a device for preparing highly dispersed and widely distributed silver powder. Background Art

[0002] In the field of conductive pastes for photovoltaics, controlling the shape or distribution of metal particles has always been a focus of attention. It can greatly affect the long-term printability of the paste and the electrical properties of the film layer after sintering. Silver powder occupies an important application position in this field.

[0003] Existing silver powder preparation often emphasizes its quasi-spherical, monodisperse, and narrowly distributed properties. However, the particle size of the prepared silver powder is often not well controlled. For example, patent CN 113658739 A discloses a method for preparing a composite quasi-spherical silver powder with controllable particle size distribution. Not only is the process complex, but the powder morphology is also poor in sphericity and consistency. The particle size distribution range of its micron and nano powders is large. Although the tap density is increased, it is difficult to accurately focus on the electrical performance differences and particle size indicators of different batches of silver powder in the application of silver paste, which increases the difficulty of slurry end-use.

[0004] Moreover, the existing silver powder preparation process is often done manually, and when multiple raw materials need to be mixed one by one, it is very troublesome and inefficient, and cannot meet the needs.

[0005] Therefore, in view of the above-mentioned deficiencies in the prior art, the present invention provides a method and apparatus for preparing highly dispersed and widely distributed silver powder. Summary of the Invention

[0006] In order to solve the above problems, the present invention designs a method and device for preparing highly dispersed and widely distributed silver powder. The method can simultaneously complete the proportioning of silver ammonia solution A, dispersant solution B, surfactant solution C and reducing solution D through a batching and mixing tank composed of an upper tank body and a movable lower base body, thereby greatly improving work efficiency.

[0007] To solve the above-mentioned technical problems, the present invention provides a highly dispersed and widely distributed silver powder preparation device, characterized in that it includes a guide rail, a flushing system, an oven, and a batching and mixing tank consisting of an upper tank body and a movable lower base body. The movable lower base body can be separated from the upper tank body and moved along the guide rail in sequence to the flushing station below the flushing system for flushing and to the heating station below the oven for drying. The guide rail is also connected to a movable cleaning component, which moves along the guide rail to the bottom of the upper tank body to flush the interior thereof. The mobile cleaning assembly is composed of a recovery frame, an annular flushing pipe and a turntable. The annular flushing pipe is set on the turntable through a lifting mechanism. The turntable is connected to the bottom of the recovery frame by the driving rotation of the rotating mechanism. Several flushing holes are opened on the inner and outer circles of the annular flushing pipe.

[0008] Further: the upper tank body is composed of an outer shell, an upper cover, a dosing tank, a storage tank and a stirring and mixing drive mechanism. The outer shell is supported on the platform by a protrusion arranged on the outer wall. A cavity for mixing and sedimentation is formed between the outer shell and the movable lower seat. The upper cover is detachably installed on the top of the outer shell. Four storage tanks are arranged on the top of the upper cover. The storage tanks are connected to the upper cover through a weighing assembly. A dosing tank is arranged directly below each of the four storage tanks. The four dosing tanks are rotatably connected to the bottom of the upper cover and connected to the stirring and mixing drive mechanism. A first electrically controlled discharge valve is provided at the bottom of the storage tank, and a second electrically controlled discharge valve is provided at the bottom of the dosing tank. The four dosing tanks are also connected to the ion water addition system.

[0009] Further: An upper connecting seat is provided at the bottom of the upper cover plate facing the position of each of the four storage tanks. The upper end of the ingredient tank is restricted in the upper connecting seat under the action of the lower connecting seat and is rotatably connected to the upper connecting seat through a first bearing provided in the upper connecting seat. The lower connecting seat is detachably connected to the upper connecting seat. The ion water addition system is connected to the four upper connecting seats, and one of the upper connecting seats is also connected to the drug addition and sampling system.

[0010] Going further: the movable lower seat body includes a lower frame, a base, an annular seat, a blocking seat, a screen structure, an upper cylinder, a support rod body, a third lifting electric cylinder and a fourth lifting electric cylinder. A circle of guide connecting grooves is provided at the bottom of the lower frame body, and a guide sealing part matching the guide connecting groove is provided on the base. The guide sealing part extends into the guide connecting groove and is connected to it through a spring. A sealing rubber ring is provided between the inner wall of the guide connecting groove and the outer wall of the guide sealing part. The annular seat is fixed to the outside of the blocking seat by a connecting rod. The screen structure is provided between the inner wall of the annular seat and the outer wall of the blocking seat. The annular seat is detachably mounted on the inner wall of the lower end of the lower frame body, and the lower end of the annular seat extends out of the lower frame body. The bottom of the base It is concave in shape, and the depth of the concave surface matches the length of the annular seat extending out of the lower frame. A groove is provided at the bottom of the base relative to the position of the blocking seat, and a drainage hole is provided in the groove. The bottom of the lower frame is provided with a pipe quick-connect joint connected to the drainage hole. An upper cylinder is vertically provided at each of the four corners of the bottom of the lower frame, and the upper end of the support rod body extends into the upper cylinder and is movably connected to it. The third lifting electric cylinder is installed on the top of the support rod body, and the fourth lifting electric cylinder is installed in the upper end of the upper cylinder. The output shaft end of the fourth lifting electric cylinder is connected to the output shaft end of the third lifting electric cylinder through a coupling. When the third lifting electric cylinder and the fourth lifting electric cylinder are both started, the blocking seat extends into the groove to seal the drainage hole.

[0011] The present invention also provides a method for preparing highly dispersed and widely distributed silver powder, which specifically comprises the following steps: S1: using deionized water to prepare a silver ammonia solution in the first batching tank in the batching mixing tank, wherein the mass concentration of the silver nitrate is 8-26%, adding a complexing agent, and adjusting the pH to 4-12 to obtain solution A; S2: using deionized water to prepare dispersant solution B in the second batching tank in the batching mixing tank, wherein the mass concentration of the dispersant is 5-40%; S3: Deionized water is used to prepare surfactant solution C through the third batching tank in the batching mixing tank, wherein the mass concentration of the surfactant is 5-20%; S4: using deionized water to prepare reducing solution D through the fourth batching tank in the batching mixing tank, wherein the mass concentration of the reducing agent is 4 to 25%; S5: First, open the second electronically controlled discharge valve at the bottom of the fourth batching tank to send the reducing liquid D therein into the mixing chamber composed of the outer shell and the lower frame. Then, open the second electronically controlled discharge valves at the bottom of the second batching tank and the third batching tank to add liquid B and liquid C into liquid D respectively, stir evenly to form a bottom liquid E, and adjust the pH to 4-8. S6: Open the second electronically controlled discharge valve at the bottom of the first batching tank and evenly add liquid A into the base liquid E. After rapid stirring for 10 minutes, let it stand and settle. S7: Move the movable lower seat to the bottom of the flushing system, and wash the silver powder precipitated by the reaction with deionized water and alcohol three times each; S8: The silver powder filtered in step S7 is moved to the bottom of the oven using the movable lower base, and dried at 60° C. for 8 hours to obtain the target silver powder.

[0012] Further: the silver ammonia complexing agent is ammonia water.

[0013] Furthermore: the pH adjuster is a combination of one or more of nitric acid, sodium hydroxide, ammonia water, ethylamines, ethanolamines, and isopropanolamines.

[0014] Furthermore: the dispersant is a non-ionic dispersant, wherein the ratio of high molecular weight to low molecular weight dispersants is 1:1, wherein the high molecular weight dispersant is one of polyvinyl pyrrolidone and polyethylene glycol, and the low molecular weight dispersant is one of Tween and isomeric alcohol polyoxyethylene ether.

[0015] Furthermore: the surfactant is obtained by compounding oleic acid and stearic acid.

[0016] Furthermore: the reducing agent is prepared by mixing sodium borohydride, formaldehyde and ascorbic acid in a ratio of 1:1:1.

[0017] After adopting the above structure, the beneficial effects of the present invention are as follows: 1. The present invention can simultaneously complete the proportioning of silver ammonia solution A, dispersant solution B, surfactant solution C and reducing solution D through the batching mixing tank composed of an upper tank body and a movable lower base body, thereby greatly improving work efficiency.

[0018] 2. The batching and mixing tank structure adopted by the present invention is to set four independent batching tanks in a mixing tank. After the ingredients are batched, they can be directly poured into the mixing tank for mixing, which plays a role in increasing practical performance.

[0019] 3. The present invention adopts a movable lower seat, through which the precipitated silver powder can be directly transported without the need for collection and transportation, thereby greatly improving work efficiency.

[0020] 4. The spherical silver powder produced by the preparation method of the present invention exhibits two well-regarded particle size distributions, a combination of micron and submicron sizes. It has high tap density, a moderate specific surface area, and good monodispersity. This has promising application prospects in areas such as solar cell silver paste and conventional conductive silver paste. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] Figure 1 Schematic diagram of the structure of the preparation device.

[0023] Figure 2 This is the structural diagram of the ingredient mixing tank.

[0024] Figure 3 for Figure 2 A magnified view of the middle panel.

[0025] Figure 4 This is the internal structure diagram of the upper tank.

[0026] Figure 5 It is the structural diagram of the movable lower seat body.

[0027] Figure 6 for Figure 5 Magnified view of B.

[0028] Figure 7 This is a structural diagram of the mobile cleaning component.

[0029] Figure 8 for Figure 7 Enlarged view of C in the middle.

[0030] Figure 9 This is a diagram of the internal structure of a pipe quick connect joint.

[0031] Figure 10 Schematic diagrams of silver powder processed by the preparation method of three embodiments of the present invention.

[0032] In the figure: 1 is the upper tank body, 2 is the upper support plate, 3 is the ion water washing tank, 4 is the alcohol storage tank, 5 is the first washing chamber, 6 is the second washing chamber, 7 is the oven, 8 is the mobile cleaning component, 9 is the mobile lower seat body, 10 is the upper cover plate, 11 is the outer shell, 12 is the raised part, 13 is the platform, 14 is the pH adjustment tank, 15 is the pH detector, 17 is the column, 18 is the extraction pump, 19 is the peristaltic pump, and 20 is the second three-way control valve Door, 21 is the first three-way control valve, 22 is the first liquid extraction pipe, 23 is the second liquid extraction pipe, 24 is the material extraction pipe, 25 is the weighing component, 26 is the storage tank, 27 is the ion water delivery main pipe, 28 is the delivery auxiliary pipe, 29 is the valve component, 30 is the upper connecting seat, 31 is the lower connecting seat, 32 is the rotating shaft, 33 is the mixing drive gear, 34 is the transmission gear, 35 is the material tank, 36 is the second electric control discharge valve, 37 is the stirring blade, 38 is The lower frame, 39 is the base, 40 is the blocking seat, 41 is the pipe quick connector, 41-1 is the first valve body, 41-1-1 is the drain groove, 41-2 is the second valve body, 41-3 is the annular valve core, 41-4 is the valve core spring, 42 is the upper cylinder, 43 is the annular flushing pipe, 44 is the second track walking wheel, 45 is the guide sealing part, 46 is the annular seat, 47 is the screen structure, 48 is the spring, 49 is the recovery frame, 50 is the electric extension Retractable rod, 51 is the first track walking wheel, 52 is the mechanical seal structure, 53 is the flange assembly, 54 is the small gear, 55 is the drive motor, 56 is the second lifting electric cylinder, 57 is the flushing pump, 58 is the clamp, 59 is the lower cylinder, 60 is the first telescopic cylinder, 61 is the second telescopic cylinder, 62 is the hose reel, 63 is the conveying hose, 64 is the first lifting electric cylinder, 65 is the large ring gear, 67 is the guide rail, 68 is the support rod body, and 69 is the turntable. DETAILED DESCRIPTION

[0033] like Figure 1The apparatus for producing highly dispersed and widely distributed silver powder shown in the figure comprises a guide rail 67, a flushing system, an oven 7, and a batching and mixing tank consisting of an upper tank body 1 and a movable lower base 9. The movable lower base 9 can be separated from the upper tank body 1 and moved along the guide rail 67 to a flushing station below the flushing system for flushing and to a heating station below the oven for drying. A movable cleaning assembly 8 is also connected to the guide rail 67, which moves along the guide rail 67 to flush the interior of the upper tank body 1. During preparation, liquid preparation, mixing, and precipitation are sequentially performed in the batching and mixing tank to produce silver powder containing the mixed liquid. The movable lower base 9 is then separated from the upper tank body 1 and carried along with the silver powder to the bottom of the flushing system for sequential ion water washing and alcohol washing to remove the mixed liquid contamination on the silver powder surface. The movable lower base 9 is then moved further, carrying the silver powder to a heating station for heating, thereby producing dried silver powder. After the movable lower seat 9 is separated from the upper tank body 1, the movable cleaning assembly 8 is moved to the bottom of the upper tank body 1, and the interior of the upper tank body 1 is rinsed by the movable cleaning assembly 8 to remove the mixed liquid and silver powder remaining in the upper tank body 1. The cleaned mixed liquid and silver powder are collected by the movable cleaning assembly 8 and re-collected, which reduces unnecessary waste of resources.

[0034] like Figure 1 The flushing system shown includes an upper support plate 2, an ion water flushing tank 3 and an alcohol tank 4 arranged on the top of the upper support plate. A first flushing chamber 5 is provided at the bottom of the upper support plate 2 directly below the ion water flushing tank 3, and a second flushing chamber 6 is provided at the bottom of the upper support plate 2 directly below the alcohol tank 4. The left and right ends of the first flushing chamber 5 and the second flushing chamber 6 are open, and the movable lower seat 9 passes through the first flushing chamber 5 and the second flushing chamber 6 in sequence along the guide rail.

[0035] like Figure 1 The oven shown is suspended, and an oven inlet is provided at its bottom. The base of the movable lower seat 9 enters the oven along the oven inlet under the action of the third lifting electric cylinder to dry the silver powder.

[0036] like Figure 7The mobile cleaning assembly 8 shown is composed of a recovery frame 49, an annular flushing pipe 43 and a turntable 69. The annular flushing pipe 43 is arranged on the turntable 69 through a lifting mechanism. The turntable 69 is driven and rotated by a rotating mechanism and is connected to the bottom of the recovery frame 49. Several flushing holes are provided on the inner and outer circles of the annular flushing pipe 43. The bottom of the recovery frame 49 is connected to the first track walking wheel 51 through an electric telescopic rod 50. A recovery hole is provided at the bottom of the recovery frame 49, and the recovery hole is connected to the recovery pipe through a flange assembly 53 provided at the bottom of the recovery frame 49. During operation, the recovery frame 49 is first lifted by the electric telescopic rod 50, so that the lower end of the upper tank body is extended into the recovery frame 49, and then the lifting mechanism is started to extend the annular flushing pipe 43 into the upper tank body, and the interior of the upper tank body is cleaned through the flushing holes opened on the inner and outer circles of the annular flushing pipe 43; the present invention can adjust the height of the annular flushing pipe 43 during the flushing process, and adopts a rotating flushing method to enable it to complete the flushing of the inner wall of the upper tank body, the outer wall of the batching tank and the stirring and mixing drive mechanism, thereby greatly improving the cleaning efficiency; and the present invention ensures that the flushing water, residual mixed liquid and silver powder can enter the recovery frame 49 for recovery and collection by lifting the recovery frame, thereby reducing unnecessary waste of resources.

[0037] like Figure 7 and Figure 8 The rotating mechanism shown includes an annular stopper seat disposed at the bottom of the recycling frame and matching the turntable, a drive motor 55, a pinion 54, and a large ring gear 65. The lower end of the turntable is rotatably connected to the annular stopper seat via a second bearing. The drive motor is mounted at the bottom of the recycling frame. The pinion 54 is mounted on the output shaft of the drive motor extending into the recycling frame. The large ring gear is mounted on the outer wall of the upper end of the turntable, and the pinion and the large ring gear are meshed with each other. The present invention rotates the turntable by controlling the drive motor and utilizing the cooperation of the pinion and the large ring gear. It has the advantages of simple structure, ease of use, and high practicality.

[0038] like Figure 8The lifting mechanism shown includes a first lifting cylinder 64, a second lifting cylinder 56, a lower cylinder 59, a first telescopic cylinder 60, and a second telescopic cylinder 61. A lower cylinder 59 is vertically fixed to the top of each end of the turntable. The lower end of the first telescopic cylinder 60 extends into the lower cylinder 59 and is slidably connected thereto. The first lifting cylinder 64 is mounted on the outer wall of the lower cylinder 59, and its shaft end is connected to the upper end of the first telescopic cylinder 60. The lower end of the second telescopic cylinder 61 extends into the first telescopic cylinder 60 and is slidably connected thereto. The second lifting cylinder 56 is mounted on the outer wall of the first telescopic cylinder 60, and its shaft end is connected to the upper end of the second telescopic cylinder 61. The annular flushing pipe 43 is fixed to the upper end of the second telescopic cylinder 61 by a clamp 58. During operation, the lifting and lowering of the annular flushing pipe 43 is achieved by controlling the first lifting cylinder 64 and the second lifting cylinder 56.

[0039] like Figure 7 and Figure 8 A flushing pump 57 that rotates together with the turntable is provided at the center of the top of the turntable shown. The flushing pump 57 is connected to the mechanical sealing structure 52 provided at the bottom of the recovery frame 49 through a first pipe. The first pipe passes through the turntable and extends out of the recovery frame and is rotatably connected to the mechanical sealing structure 52. The mechanical sealing structure 52 is connected to the water storage tank through a second pipe. A hose reel 62 is provided on each turntable on both sides of the flushing pump 57. The hose reel 62 is rotatably connected to the turntable and a diversion cavity is opened on its inner wall. The flushing pump 57 is connected to the diversion cavity in the hose reel 62 through a third pipe. One end of the third pipe is rotatably connected to the top of the hose reel 62. A conveying hose 63 is wrapped around the surface of the hose reel 62. One end of the conveying hose 63 is fixed on the hose reel 62 and is connected to its diversion cavity. The other end of the conveying hose 63 extends into the lifting mechanism and is connected to the annular flushing pipe 43. When the annular flushing pipe is lifted, the delivery hose will automatically pull the hose reel 62 to rotate. When the annular flushing pipe is retracted, the hose will be retracted by rotating the hose reel 62 in the reverse direction.

[0040] like Figure 2 and Figure 4The upper tank body 1 shown is composed of an outer shell 11, an upper cover plate 10, a dosing tank 35, a storage tank 26 and a stirring and mixing drive mechanism. The outer shell 11 is supported on a platform 13 by a raised portion 12 integrally provided on the outer wall. The platform 13 is suspended by a number of columns 17 provided at the bottom. A cavity for mixing and sedimentation is formed between the outer shell 11 and the movable lower seat 9. The upper cover plate 10 is detachably mounted on the top of the outer shell 11. Four storage tanks 26 are provided on the top of the upper cover plate. The storage tanks are connected to the upper cover plate 10 through a weighing assembly. A dosing tank 35 is provided directly below each of the four storage tanks 26. The four dosing tanks 35 are rotatably connected to the bottom of the upper cover plate 10 and are connected to the stirring and mixing drive mechanism. A first electrically controlled discharge valve is provided at the bottom of the storage tank 26, and a second electrically controlled discharge valve 36 is provided at the bottom of the dosing tank 35. The four dosing tanks are also connected to an ion water addition system. During operation, silver ammonia solution A, dispersant solution B, surfactant solution C and reducing solution D are respectively proportioned in four batching tanks through four storage tanks 26 and ion water adding system, and then the dispersant solution B, surfactant solution C and reducing solution D are all poured into the batching mixing tank composed of the upper tank body 1 and the movable lower base body 9, and stirred evenly to form a base liquid E. Then, the silver ammonia solution A is added to the batching mixing tank and stirred rapidly to precipitate the silver powder.

[0041] like Figure 4 The bottom of the upper cover plate is shown as facing each of the four storage tanks, with an upper connecting seat 30 provided. The upper end of the mixing tank 35 is restrained within the upper connecting seat 30 by the action of the lower connecting seat 31 and is rotatably connected thereto via a first bearing provided therein. The lower connecting seat 31 is detachably connected to the upper connecting seat 30. The ionized water addition system is connected to the four upper connecting seats 30, one of which is also connected to the reagent addition and sampling system. The upper connecting seat connected to the reagent addition and sampling system is also connected to the complexing agent addition pipeline. The present invention can detect and adjust the pH value of the silver ammonia solution A and the pH value in the mixing tank through the reagent addition and sampling system, and adjust them according to the detection structure.

[0042] like Figure 4The stirring and mixing drive mechanism shown includes a rotary motor, a rotating shaft 32, a mixing drive gear 33, a transmission gear 34 and a stirring blade 37. The rotary motor is installed at the center of the top of the upper cover plate 10. The output shaft of the rotary motor passes through the upper cover plate 10 and is connected to the vertically arranged rotating shaft 32. The rotating shaft 32 is rotated by the drive of the rotary motor. The mixing drive gear 33 is mounted on the rotating shaft 32 and rotates together. A transmission gear 34 is fixed on each outer wall of the four batching tanks 35. The mixing drive gear 33 is meshed with the four transmission gears 34. The four batching tanks rotate separately through gear transmission. The stirring blade 37 is mounted on the lower end of the rotating shaft and rotates together. The stirring blade is located directly below the batching tank. The present invention can not only rotate the four batching tanks to complete the batching work by the rotary motor, but also can use the stirring blade at the lower end of the rotating shaft to complete the stirring and mixing work of the whole after the batching is completed, thereby increasing practicality.

[0043] like Figure 4 The ionized water addition system shown includes two ionized water delivery main pipes 27, an auxiliary delivery pipe 28, and a valve assembly 29 with a flow meter. One end of the ionized water delivery main pipe 27 is connected to the ionized water storage tank. The valve assembly 29 is arranged on the auxiliary delivery pipe 28. One end of the auxiliary delivery pipe 28 is connected to the ionized water delivery main pipe 27, and the other end of the auxiliary delivery pipe 28 is connected to the batching tank 35 through the upper connecting seat 30. Every two batching tanks 35 are connected to one ionized water delivery main pipe 27. During operation, the delivery amount of ionized water is accurately controlled by the display of the flow meter.

[0044] like Figure 4 The storage tank 26 is connected to the upper cover via a weighing assembly 25. The weighing assembly 25 comprises a support base, a load cell, and an annular support plate. The annular support plate is positioned within the support base via the load cell. The lower end of the storage tank extends into the support base and is supported by the annular support plate. Slots are defined at the bottom of the support base and on the upper cover relative to the first electrically controlled discharge valve. During operation, the load cell's indication accurately controls the amount of raw material discharged from the storage tank.

[0045] like Figure 2 and Figure 3The drug addition and sampling system shown includes a pH detector 15, a pH adjustment storage tank 14, a suction pump 18, a peristaltic pump 19, a first three-way control valve 21 and a second three-way control valve 20. The first three-way control valve 20 and the second three-way control valve 21 are respectively installed on the inner and outer walls of the upper tank body and are connected to each other. The first three-way control valve is also respectively connected to the first liquid extraction pipe 22 and the second liquid extraction pipe 23. The first liquid extraction pipe 22 passes through the upper connecting seat and extends into the bottom of the material tank, and the second liquid extraction pipe extends to the lower end of the material mixing tank. The peristaltic pump is installed on the outer wall of the upper tank body and its inlet and outlet are respectively connected to the second three-way control valve and the pH detector. The suction pump 18 is arranged at the top of the pH adjustment storage tank and is connected to it. The suction pump is also connected to the second three-way control valve 20 through the suction pipe 24. During operation, the peristaltic pump is first started to perform sampling, and a corresponding amount of pH adjustment is added using the extraction pump according to the display result of the pH detector. The present invention can automatically complete pH detection and adjustment work by adopting the above design, which plays a role in increasing practical performance.

[0046] like Figure 5 and Figure 6The movable lower seat body 9 shown includes a lower frame 38, a base 39, an annular seat 46, a blocking seat 40, a screen structure 47, an upper cylinder 42, a support rod body 68, a third lifting electric cylinder and a fourth lifting electric cylinder. The bottom of the lower frame 38 is provided with a circle of guide connecting grooves, and the base is provided with a guide sealing portion 45 matching the guide connecting grooves. The guide sealing portion 45 extends into the guide connecting grooves and is connected thereto through a spring 48. A sealing rubber ring is provided between the inner wall of the guide connecting groove and the outer wall of the guide sealing portion. The annular seat 46 is fixed to the outside of the blocking seat 40 by a connecting rod. The screen structure 47 is provided between the inner wall of the annular seat 46 and the outer wall of the blocking seat 40. The annular seat is detachably mounted on the inner wall of the lower end of the lower frame 38, and the lower end of the annular seat extends out of the lower frame. The bottom of the base is concave, and the depth of the concave surface matches the length of the annular seat extending out of the lower frame. A groove is provided at the bottom of the base relative to the position of the blocking seat 40, and a drainage hole is provided in the groove. The bottom of the lower frame is provided with a pipe quick-connect joint 41 connected to the drainage hole. An upper cylinder 42 is vertically provided at each of the four corners of the bottom of the lower frame 38. The upper end of the support rod 68 extends into the upper cylinder 42 and is movably connected to it. The third lifting cylinder is installed on the top of the support rod 68, and the fourth lifting cylinder is installed in the upper end of the upper cylinder 42. The output shaft end of the fourth lifting cylinder is connected to the output shaft end of the third lifting cylinder through a coupling. When the third lifting cylinder and the fourth lifting cylinder are started, the blocking seat 40 extends into the groove to seal the drainage hole. During operation, first start the third lifting electric cylinder and the fourth lifting electric cylinder and use the sealing seat 40 to seal the leakage hole. After the stirring and sedimentation is completed, first connect it to the mixed liquid recovery pipe through the pipe quick connector, and then close the fourth lifting electric cylinder. The lower frame and the base will be displaced under the action of the spring, thereby opening the leakage hole, and the mixed liquid will flow out along the leakage hole. The precipitated silver powder will remain in the base through the screen structure. After the movable lower seat is separated from the upper tank body, the third lifting electric cylinder is closed, and the movable lower seat is moved by the second track walking wheel 44 set at the bottom of the support rod body 68.

[0047] like Figure 9The illustrated pipe quick-connect connector 41 includes a first valve body 41-1, a second valve body 41-2, an annular valve core 41-3, and a valve core spring 41-4. The upper end of the first valve body is connected to the drain hole, and the lower end of the first valve body extends into the second valve body and forms a seal. The first and second valve bodies are fixedly connected. The annular valve core is piston-type connected between the outer wall of the first valve body and the inner wall of the second valve body and is connected to the second valve body via a valve core spring. A drain groove 41-1-1 is formed on the side wall of the first valve body within the second valve body. The drain groove 41-1-1 is sealed by the annular valve core. The inner wall of the second valve body away from the first valve body is provided with an internal thread. When connected, the external pipe is extended into the second valve body through the cooperation of the internal and external threads, squeezing the annular valve core, thereby opening the drain groove and discharging the mixed liquid. The present invention adopts this structure to achieve the purpose of rapid disassembly and assembly.

[0048] Example 1:

[0049] The present invention provides a method for preparing highly dispersed and widely distributed silver powder, which specifically comprises the following steps: S1: using deionized water to prepare a silver ammonia solution in the first batch mixing tank, wherein the mass concentration of the silver nitrate is 8%, adding a complexing agent, and adjusting the pH to 4 to obtain solution A; S2: Deionized water is used to prepare dispersant solution B through the second batching tank in the batching mixing tank, wherein the mass concentration of the dispersant is 5%; S3: Deionized water is used to prepare surfactant solution C through the third batching tank in the batching mixing tank, wherein the mass concentration of the surfactant is 5%; S4: using deionized water to prepare reducing solution D through the fourth batching tank in the batching mixing tank, wherein the mass concentration of the reducing agent is 4%; S5: First, open the second electronically controlled discharge valve at the bottom of the fourth batching tank to send the reducing liquid D therein into the mixing chamber composed of the outer shell and the lower frame. Then, open the second electronically controlled discharge valves at the bottom of the second batching tank and the third batching tank to add liquid B and liquid C into liquid D respectively, stir evenly to form a bottom liquid E, and adjust the pH to 4. S6: Open the second electronically controlled discharge valve at the bottom of the first batching tank and evenly add liquid A into the base liquid E. After rapid stirring for 10 minutes, let it stand and settle. S7: Move the movable lower seat to the bottom of the flushing system, and wash the silver powder precipitated by the reaction with deionized water and alcohol three times each; S8: The silver powder filtered in step S7 is moved to the bottom of the oven using the movable lower base, and dried at 60° C. for 8 hours to obtain the target silver powder.

[0050] The complexing agent in the above method is ammonia water, and the pH adjuster is a combination of one or more of nitric acid, sodium hydroxide, ammonia water, ethylamines, ethanolamines, and isopropanolamines. The above dispersant is a nonionic dispersant, wherein the ratio of high molecular weight to low molecular weight dispersants is 1:1, wherein the high molecular weight dispersant is one of polyvinyl pyrrolidone and polyethylene glycol, and the low molecular weight dispersant is one of Tween and isomeric alcohol polyoxyethylene ether. The above surfactant is obtained by compounding oleic acid and stearic acid. The above reducing agent is obtained by mixing sodium borohydride, formaldehyde, and ascorbic acid in a ratio of 1:1:1.

[0051] Silver powder was obtained by this method. Figure 10 As shown, the micron-sized particles outnumber the submicron-sized particles by 4-5 times. The silver powder tested had a high tap density, a moderate specific surface area, and good monodispersity. It has promising applications in solar cell silver pastes and traditional conductive silver pastes.

[0052] Example 2:

[0053] The present invention provides a method for preparing highly dispersed and widely distributed silver powder, which specifically comprises the following steps: S1: using deionized water to prepare a silver ammonia solution in the first batch mixing tank, wherein the mass concentration of the silver nitrate is 15%, adding a complexing agent, and adjusting the pH to 7 to obtain solution A; S2: Dispersant solution B is prepared using deionized water in the second batching tank in the batching mixing tank, wherein the mass concentration of the dispersant is 22%; S3: Deionized water is used to prepare surfactant solution C through the third batching tank in the batching mixing tank, wherein the mass concentration of the surfactant is 12%; S4: using deionized water to prepare reducing solution D through the fourth batching tank in the batching mixing tank, wherein the mass concentration of the reducing agent is 15%; S5: First, open the second electronically controlled discharge valve at the bottom of the fourth batching tank to send the reducing liquid D therein into the mixing chamber composed of the outer shell and the lower frame. Then, open the second electronically controlled discharge valves at the bottom of the second batching tank and the third batching tank to add liquid B and liquid C into liquid D respectively, stir evenly to form a bottom liquid E, and adjust the pH to 6. S6: Open the second electronically controlled discharge valve at the bottom of the first batching tank and evenly add liquid A into the base liquid E. After rapid stirring for 10 minutes, let it stand and settle. S7: Move the movable lower seat to the bottom of the flushing system, and wash the silver powder precipitated by the reaction with deionized water and alcohol three times each; S8: The silver powder filtered in step S7 is moved to the bottom of the oven using the movable lower base, and dried at 60° C. for 8 hours to obtain the target silver powder.

[0054] Silver powder was obtained by this method. Figure 10 As shown, the number of micron and submicron particles is roughly the same. The silver powder has a high tap density, a moderate specific surface area, and good monodispersity after testing. It has good application prospects in solar cell silver paste and traditional conductive silver paste.

[0055] Example 3:

[0056] The present invention also provides a method for preparing highly dispersed and widely distributed silver powder, which specifically comprises the following steps: S1: using deionized water to prepare a silver ammonia solution in the first batch mixing tank, wherein the mass concentration of the silver nitrate is 26%, adding a complexing agent, and adjusting the pH to 12 to obtain solution A; S2: Deionized water is used to prepare dispersant solution B through the second batching tank in the batching mixing tank, wherein the mass concentration of the dispersant is 40%; S3: Deionized water is used to prepare surfactant solution C through the third batching tank in the batching mixing tank, wherein the mass concentration of the surfactant is 20%; S4: using deionized water to prepare reducing solution D through the fourth batching tank in the batching mixing tank, wherein the mass concentration of the reducing agent is 25%; S5: First, open the second electronically controlled discharge valve at the bottom of the fourth batching tank to send the reducing liquid D therein into the mixing chamber composed of the outer shell and the lower frame. Then, open the second electronically controlled discharge valves at the bottom of the second batching tank and the third batching tank to add liquid B and liquid C into liquid D respectively, stir evenly to form a bottom liquid E, and adjust the pH to 8. S6: Open the second electronically controlled discharge valve at the bottom of the first batching tank and evenly add liquid A into the base liquid E. After rapid stirring for 10 minutes, let it stand and settle. S7: Move the movable lower seat to the bottom of the flushing system, and wash the silver powder precipitated by the reaction with deionized water and alcohol three times each; S8: The silver powder filtered in step S7 is moved to the bottom of the oven using the movable lower base, and dried at 60° C. for 8 hours to obtain the target silver powder.

[0057] Silver powder was obtained by this method. Figure 10 As shown, the submicron particles outnumber the micron particles by 3 to 5 times. The silver powder tested exhibited high tap density, moderate specific surface area, and good monodispersity. This suggests promising applications in solar cell silver pastes and conventional conductive silver pastes.

[0058] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions based on the principles of the present invention are within the scope of protection of the present invention. It should be noted that for those skilled in the art, various improvements and modifications that do not depart from the principles of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A device for preparing highly dispersed and widely distributed silver powder, characterized by: The invention comprises a guide rail, a flushing system, an oven, and a batching mixing tank composed of an upper tank body and a movable lower base body. The movable lower base body can be separated from the upper tank body and moved along the guide rail to the flushing station below the flushing system for flushing and to the heating station below the oven for drying. The guide rail is also connected to a movable cleaning component, which moves along the guide rail to the bottom of the upper tank body to flush the interior thereof. The mobile cleaning assembly is composed of a recovery frame, an annular flushing pipe and a turntable. The annular flushing pipe is set on the turntable through a lifting mechanism. The turntable is connected to the bottom of the recovery frame by the driving rotation of the rotating mechanism. Several flushing holes are opened on the inner and outer circles of the annular flushing pipe.

2. The device for preparing highly dispersed and widely distributed silver powder according to claim 1, characterized in that: The upper tank body is composed of an outer shell, an upper cover, a dosing tank, a storage tank and a stirring and mixing drive mechanism. The outer shell is supported on the platform by a protrusion arranged on the outer wall. A cavity for mixing and sedimentation is formed between the outer shell and the movable lower seat. The upper cover is detachably mounted on the top of the outer shell. Four storage tanks are arranged on the top of the upper cover. The storage tanks are connected to the upper cover through a weighing assembly. A dosing tank is arranged directly below each of the four storage tanks. The four dosing tanks are rotatably connected to the bottom of the upper cover and connected to the stirring and mixing drive mechanism. A first electrically controlled discharge valve is provided at the bottom of the storage tank, and a second electrically controlled discharge valve is provided at the bottom of the dosing tank. The four dosing tanks are also connected to an ion water addition system.

3. The device for preparing highly dispersed and widely distributed silver powder according to claim 2, characterized in that: An upper connecting seat is provided at the bottom of the upper cover plate facing the position of each of the four storage tanks. The upper end of the ingredient tank is restricted in the upper connecting seat under the action of the lower connecting seat and is rotatably connected to the upper connecting seat through a first bearing provided in the upper connecting seat. The lower connecting seat is detachably connected to the upper connecting seat. The ion water adding system is connected to the four upper connecting seats, and one of the upper connecting seats is also connected to the medicine adding and sampling system.

4. The device for preparing highly dispersed and widely distributed silver powder according to claim 1, characterized in that: The movable lower seat body includes a lower frame, a base, an annular seat, a blocking seat, a screen structure, an upper cylinder, a support rod body, a third lifting electric cylinder and a fourth lifting electric cylinder. A circle of guide connecting grooves is provided at the bottom of the lower frame body, and a guide sealing part matching the guide connecting groove is provided on the base. The guide sealing part extends into the guide connecting groove and is connected thereto through a spring. A sealing rubber ring is provided between the inner wall of the guide connecting groove and the outer wall of the guide sealing part. The annular seat is fixed to the outside of the blocking seat by a connecting rod. The screen structure is provided between the inner wall of the annular seat and the outer wall of the blocking seat. The annular seat is detachably mounted on the inner wall of the lower end of the lower frame body, and the lower end of the annular seat extends out of the lower frame body. The bottom of the base is concave The bottom of the base is provided with a groove relative to the position of the sealing seat, and a drainage hole is provided in the groove. The bottom of the lower frame is provided with a pipe quick-connect joint connected to the drainage hole. An upper cylinder is vertically provided at each of the four corners of the bottom of the lower frame, and the upper end of the support rod body extends into the upper cylinder and is movably connected to it. The third lifting electric cylinder is installed on the top of the support rod body, and the fourth lifting electric cylinder is installed in the upper end of the upper cylinder. The output shaft end of the fourth lifting electric cylinder is connected to the output shaft end of the third lifting electric cylinder through a coupling. When the third lifting electric cylinder and the fourth lifting electric cylinder are started, the blocking seat extends into the groove to seal the drainage hole.

5. A method for preparing highly dispersed and widely distributed silver powder using the apparatus for preparing highly dispersed and widely distributed silver powder according to claim 2, characterized in that: The specific steps include: S1: using deionized water to prepare a silver ammonia solution in the first batching tank in the batching mixing tank, wherein the mass concentration of the silver nitrate is 8-26%, adding a complexing agent, and adjusting the pH to 4-12 to obtain solution A; S2: using deionized water to prepare dispersant solution B in the second batching tank in the batching mixing tank, wherein the mass concentration of the dispersant is 5-40%; S3: Deionized water is used to prepare surfactant solution C through the third batching tank in the batching mixing tank, wherein the mass concentration of the surfactant is 5-20%; S4: using deionized water to prepare reducing solution D through the fourth batching tank in the batching mixing tank, wherein the mass concentration of the reducing agent is 4 to 25%; S5: First, open the second electronically controlled discharge valve at the bottom of the fourth batching tank to send the reducing liquid D therein into the mixing chamber composed of the outer shell and the lower frame. Then, open the second electronically controlled discharge valves at the bottom of the second batching tank and the third batching tank to add liquid B and liquid C into liquid D respectively, stir evenly to form a bottom liquid E, and adjust the pH to 4-8. S6: Open the second electronically controlled discharge valve at the bottom of the first batching tank and evenly add liquid A into the base liquid E. After rapid stirring for 10 minutes, let it stand and settle. S7: Move the movable lower seat to the bottom of the flushing system, and wash the silver powder precipitated by the reaction with deionized water and alcohol three times each; S8: The silver powder filtered in step S7 is moved to the bottom of the oven using the movable lower base, and dried at 60° C. for 8 hours to obtain the target silver powder.

6. The method for preparing highly dispersed and widely distributed silver powder according to claim 5, characterized in that: The complexing agent is ammonia water.

7. The method for preparing highly dispersed and widely distributed silver powder according to claim 5, wherein: The pH adjuster is a combination of one or more of nitric acid, sodium hydroxide, ammonia water, ethylamines, ethanolamines, and isopropanolamines.

8. The method for preparing highly dispersed and widely distributed silver powder according to claim 5, wherein: The dispersant is a nonionic dispersant, wherein the ratio of high molecular weight dispersant to low molecular weight dispersant is 1:1, wherein the high molecular weight dispersant is one of polyvinyl pyrrolidone and polyethylene glycol, and the low molecular weight dispersant is one of Tween and isomeric alcohol polyoxyethylene ether.

9. The method for preparing highly dispersed and widely distributed silver powder according to claim 5, wherein: The surfactant is obtained by compounding oleic acid and stearic acid.

10. The method for preparing highly dispersed and broadly distributed silver powder according to claim 5, wherein: The reducing agent is prepared by mixing sodium borohydride, formaldehyde and ascorbic acid in a ratio of 1:1:1.

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