Airflow crushing and collecting system suitable for producing spherical silver powder through liquid phase reduction method

Abstract

The utility model discloses an airflow crushing and collecting system suitable for producing spherical silver powder through a liquid phase reduction method, and particularly relates to the field of solar cell panel production, which comprises a fluidized bed airflow crushing mechanism, a cyclone separator, a metal film dust removal mechanism and an induced draft fan, a spiral feeder is arranged on one side of the fluidized bed, a material classifier is arranged at the upper end of the fluidized bed, one end of the material classifier is connected with a cyclone separator through a pipeline, an outlet in the top end of the cyclone separator is communicated with a metal film dust removal mechanism through a pipeline, and the metal film dust removal mechanism is connected with an induced draft fan through a pipeline. The filtering element formed by sintering the metal short fibers has the advantages of being high in precision, large in air permeability and capable of being regenerated through reverse blowing, silver powder escaping from the cyclone separator can be intercepted by 100%, and the device is key equipment for improving the yield of the silver powder and is small in occupied area, long in service life and high in economical efficiency.

Description

Technical Field

[0001] The utility model relates to the technical field of solar cell panel production, in particular to an airflow crushing and collecting system suitable for producing spherical silver powder by a liquid phase reduction method. Background Art

[0002] Photovoltaic silver paste is an indispensable core auxiliary material for the construction of solar cells, and its quality directly affects the performance of solar cells. Photovoltaic silver paste is a formulated product. Its main production raw materials include silver powder, resin bonding phase, solvent, additives, glass powder, etc., which together form a formula and are also the key to preparing excellent paste. Among them, the silver powder content in silver paste accounts for the highest proportion, usually accounting for 80%-90%. Therefore, silver powder is also considered to be the most core material in silver paste.

[0003] The silver powder of the conductive silver paste for solar cells mainly includes spherical silver powder and flake silver powder. Generally speaking, spherical and quasi-spherical silver powders are often prepared by chemical synthesis, while flake silver powders are mainly prepared by mechanical ball milling. Spherical silver powder has a relatively uniform particle distribution, which can improve the light absorption and photoelectric conversion efficiency of solar cells and is widely used in the production process of solar cells. Spherical silver powder is mainly produced by liquid phase reduction method. The liquid phase reduction method is based on the principle of redox reaction, and a reducing agent is used in a liquid phase system to reduce silver salt (oxidant) to silver powder. The production equipment required for this method is simple, the cost is low, the process conditions are easy to control, and it is suitable for industrial production. This process is the main method used by most silver powder manufacturers. The process equipment investment is small, the production cycle is short, the cost is low, the process conditions are easy to control, and it is easy to scale production. Usually, uniform particle size, good dispersibility, and tap density higher than 4g·m -3 The spherical or quasi-spherical silver powder is used to prepare the silver paste, which has excellent screen printing properties and can be used as the positive silver electrode after sintering.

[0004] The ultrafine spherical silver powder generated in the liquid phase will agglomerate after drying. In order to ensure the particle size of the final product, the dried silver powder needs to be put into a jet mill and crushed before being used in the production of solar panels. At present, the industry generally adopts a disc mill plus an ordinary dust collector, which has low processing capacity and cannot guarantee crushing uniformity and device continuity. At the same time, the silver powder recovery rate is low and the economic efficiency is poor. Utility Model Content

[0005] The utility model aims to provide an airflow pulverizing and collecting system suitable for producing spherical silver powder by liquid phase reduction method, so as to solve the problems raised in the above background technology.

[0006] In order to solve the above technical problems, the utility model provides the following technical solutions: an airflow pulverizing and collecting system suitable for producing spherical silver powder by liquid phase reduction method, comprising a fluidized bed airflow pulverizing mechanism, a cyclone separator, a metal film dust removal mechanism and an induced draft fan, wherein the fluidized bed airflow pulverizing mechanism comprises a fluidized bed, a spiral feeder is arranged on one side of the fluidized bed, a material classifier is arranged on the upper end of the fluidized bed, one end of the material classifier is connected to the cyclone separator through a pipeline, the top outlet of the cyclone separator is connected to the metal film dust removal mechanism through a pipeline, and the metal film dust removal mechanism is connected to the induced draft fan through a pipeline.

[0007] In a preferred embodiment, an air flow inlet pipe is provided at the lower end of the fluidized bed, and one end of the air flow inlet pipe located inside the fluidized bed is connected to an air flow nozzle. The air flow inlet pipe and the air flow nozzle can break up the agglomerated silver powder.

[0008] In a preferred embodiment, the material classifier includes a fixedly installed driving motor, the output shaft of the driving motor is fixedly connected to a material classifying wheel installed inside the material classifier, and the driving motor can classify the silver powder when driving the material classifying wheel to rotate.

[0009] In a preferred embodiment, the metal film dust removal mechanism includes a cylinder, a filter element is arranged inside the cylinder, a backblowing assembly is arranged on the upper end of the filter element, and the upper end of the filter element is mounted on a mounting plate. The filter element is a filter element sintered from metal staple fibers. The filter element sintered from metal staple fibers has the characteristics of high precision, high air permeability and regeneration by backblowing. It can 100% intercept the silver powder escaping from the cyclone separator and is a key equipment for improving the yield of silver powder.

[0010] In a preferred embodiment, the backblowing assembly includes a plurality of backblowing nozzles, each of which is connected to a backblowing air bag via a pipeline, and a backblowing valve is provided on the pipeline between each backblowing nozzle and the backblowing air bag. The online backblowing assembly can work and backblow at the same time to ensure continuous operation of the system.

[0011] In a preferred embodiment, a collecting hopper is provided at the bottom end of the cyclone separator, and at least four air flow nozzles are provided.

[0012] Compared with the prior art, the beneficial effects achieved by the utility model are:

[0013] The utility model adds the dried silver powder into the screw feeder, and under the action of the screw feeder, it enters the bottom of the fluidized bed, and the compressed gas enters the airflow nozzle through the airflow inlet pipe. The high-speed airflow ejected from the airflow nozzle breaks up the agglomerated silver powder, and the broken silver powder moves upward under the suction of the induced draft fan, and is classified by the material classification wheel. The silver powder with the particle size meeting the requirements is discharged from the fluidized bed, and the silver powder with the particle size larger than the required value returns to the fluidized bed to be crushed again. The classified silver powder is processed by the cyclone separator and then enters the metal film dust removal mechanism to achieve the filtering treatment of the silver powder. In addition, an online back-blowing component is arranged in the metal film dust removal mechanism, which can back-blow while working to ensure the continuous operation of the system. The utility model adopts a filter element sintered from metal staple fibers, which has the characteristics of high precision, high air permeability, and regeneration by back-blowing. It can 100% intercept the silver powder escaping from the cyclone separator, and is a key device for improving the yield of silver powder. In addition, the device occupies a small area, has a long service life, and has high economic efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0015] Figure 1 It is a schematic diagram of the overall structure of the utility model.

[0016] In the figure: 1. Cyclone separator; 2. induced draft fan; 3. fluidized bed; 4. screw feeder; 5. material classifier; 6. air flow inlet pipe; 7. air flow nozzle; 8. cylinder; 9. filter element; 10. mounting plate; 11. back-blowing nozzle; 12. back-blowing air bag; 13. back-blowing valve; 14. collecting hopper. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0018] See also Figure 1The utility model provides an air flow pulverizing and collecting system suitable for producing spherical silver powder by liquid phase reduction method, comprising a fluidized bed air flow pulverizing mechanism, a cyclone separator 1, a metal film dust removal mechanism and an induced draft fan 2, wherein the fluidized bed air flow pulverizing mechanism comprises a fluidized bed 3, a screw feeder 4 is arranged on one side of the fluidized bed 3, a material classifier 5 is arranged on the upper end of the fluidized bed 3, one end of the material classifier 5 is connected to the cyclone separator 1 through a pipeline, the top outlet of the cyclone separator 1 is connected to the metal film dust removal mechanism through a pipeline, and the metal film dust removal mechanism is connected to the induced draft fan 2 through a pipeline.

[0019] In a preferred embodiment, an air flow inlet pipe 6 is provided at the lower end of the fluidized bed 3, and one end of the air flow inlet pipe 6 located inside the fluidized bed 3 is connected to an air flow nozzle 7. During specific use, the air flow pulverizing gas inlet pressure is -0.5MPa, and the inlet pressure of the induced draft fan 2 is about -4kpa.

[0020] In a preferred embodiment, the material classifier 5 includes a fixedly arranged driving motor, and an output shaft of the driving motor is fixedly connected to a material classifying wheel arranged inside the material classifier 5 .

[0021] In a preferred embodiment, the metal film dust removal mechanism includes a cylinder 8, a filter element 9 is arranged inside the cylinder 8, a backblowing assembly is arranged at the upper end of the filter element 9, and the upper end of the filter element 9 is installed on a mounting plate 10. The filter element 9 is a filter element sintered from metal staple fibers. The filter element sintered from metal staple fibers has the characteristics of high precision, high air permeability and regeneration by backblowing. It can 100% intercept the silver powder escaping from the cyclone separator, and is a key equipment for improving the silver powder yield.

[0022] In a preferred embodiment, the back-blowing assembly includes a plurality of back-blowing nozzles 11, each of the back-blowing nozzles 11 is connected to a back-blowing air bag 12 through a pipeline, and a back-blowing valve 13 is provided on the pipeline between each back-blowing nozzle 11 and the back-blowing air bag 12. After the metal film dust removal mechanism works to a set period, the partitioned pulse back-blowing valves 13 are opened in sequence, and the back-blowing gas passes through the filter element 9 in the reverse direction from the pipeline and the back-blowing nozzle 11 to break the filter cake on the outer surface of the filter element, thereby completing the regeneration of the filter element.

[0023] In a preferred embodiment, a collecting hopper 14 is provided at the bottom end of the cyclone separator 1, and at least four air flow nozzles 7 are provided.

[0024] The working principle of the utility model is:

[0025] The dried silver powder is added from the feed port on the screw feeder 4, and enters the bottom of the fluidized bed 3 under the action of the screw feeder 4. The compressed gas enters the airflow nozzle 7 through the airflow inlet pipe 6. The high-speed airflow ejected from the airflow nozzle 7 breaks up the agglomerated silver powder. The broken silver powder moves upward under the suction force of the induced draft fan 2, and is classified by the material classification wheel. The silver powder with the particle size meeting the requirements is discharged from the air outlet at the upper end of the fluidized bed 3, and the silver powder with the particle size larger than the required value returns to the fluidized bed 3 to be crushed again;

[0026] The outlet pipeline of the fluidized bed 3 is located at the top of the fluidized bed 3 and is connected to the inlet of the cyclone separator 1. The silver powder processed by the fluidized bed air flow crushing mechanism enters the cyclone separator 1. Most of the silver powder is collected by the cyclone separator 1 and falls into the collecting hopper 14 at the bottom. A small amount of very fine silver powder escapes from the top outlet of the cyclone separator 1. The outlet of the cyclone separator 1 is connected to the inlet of the metal film dust removal mechanism.

[0027] The escaped silver powder is connected to the inlet of the metal film dust removal mechanism. The metal film dust removal mechanism is designed with an installation plate 10 for the filter element 9. The bottom is the silver powder discharge port, and the upper part is mainly the backblowing component installation area. The backblowing component is designed with multiple backblowing nozzles 11, and each backblowing nozzle 11 corresponds to a filter element 9 to ensure that the silver powder on the surface of the filter element can be backblown clean; the metal film dust removal mechanism is designed with a backblowing air bag 12, which serves as a buffer tank for backblowing air. The backblowing air enters the backblowing air bag 12 from the pipeline through the backblowing air inlet. When backblowing is required, the backblowing valve 13 is opened in sequence, and the backblowing air stored in the backblowing air bag 12 enters the backblowing nozzle 11 from the backblowing valve 13, and forms a supersonic airflow through the backblowing nozzle 11 to complete the effective backblowing of the filter element 9; the filtered gas passes through the outlet of the metal film dust removal mechanism and is discharged from the system from the exhaust port under the action of the induced draft fan.

[0028] Finally, it should be noted that the above description is only a preferred embodiment of the utility model and is not intended to limit the utility model. Although the utility model is described in detail with reference to the above embodiments, those skilled in the art can still modify the technical solutions recorded in the above embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.

Claims

1. An airflow pulverizing and collecting system suitable for producing spherical silver powder by liquid phase reduction method, characterized in that: The invention comprises a fluidized bed air flow pulverizing mechanism, a cyclone separator (1), a metal film dust removal mechanism and an induced draft fan (2), wherein the fluidized bed air flow pulverizing mechanism comprises a fluidized bed (3), a screw feeder (4) is arranged on one side of the fluidized bed (3), a material classifier (5) is arranged on the upper end of the fluidized bed (3), one end of the material classifier (5) is connected to the cyclone separator (1) via a pipeline, the top outlet of the cyclone separator (1) is connected to the metal film dust removal mechanism via a pipeline, and the metal film dust removal mechanism is connected to the induced draft fan (2) via a pipeline.

2. The airflow pulverizing and collecting system for producing spherical silver powder by liquid phase reduction method according to claim 1, characterized in that: An airflow inlet pipe (6) is provided at the lower end of the fluidized bed (3); one end of the airflow inlet pipe (6) located inside the fluidized bed (3) is connected to an airflow nozzle (7).

3. The airflow pulverizing and collecting system for producing spherical silver powder by liquid phase reduction method according to claim 1, characterized in that: The material classifier (5) comprises a fixedly arranged drive motor, wherein the output shaft of the drive motor is fixedly connected to a material classifying wheel arranged inside the material classifier (5).

4. The airflow pulverizing and collecting system for producing spherical silver powder by liquid phase reduction method according to claim 1, characterized in that: The metal film dust removal mechanism comprises a cylinder (8), a filter element (9) is arranged inside the cylinder (8), a backflush assembly is arranged at the upper end of the filter element (9), the upper end of the filter element (9) is mounted on a mounting plate (10), and the filter element (9) is a filter element formed by sintering metal staple fibers.

5. The airflow pulverizing and collecting system for producing spherical silver powder by liquid phase reduction method according to claim 4, characterized in that: The back-blowing assembly comprises a plurality of back-blowing nozzles (11), each of the back-blowing nozzles (11) is connected to a back-blowing air bag (12) via a pipeline, and a back-blowing valve (13) is provided on the pipeline between each of the back-blowing nozzles (11) and the back-blowing air bag (12).

6. The airflow pulverizing and collecting system for producing spherical silver powder by liquid phase reduction method according to claim 2, characterized in that: A collecting hopper (14) is provided at the bottom end of the cyclone separator (1), and at least four air flow nozzles (7) are provided.

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