Ultrafine silver powder airflow drying device

Abstract

The utility model discloses a superfine silver powder airflow drying device, and belongs to the technical field of precious metal powder drying. According to the drying device disclosed by the utility model, due to the arrangement of the reducing pipe type airflow drying device and the arrangement of the gas distribution plate and the reducing module, the silver powder wet material is uniformly distributed and violently disturbed in the hot airflow in the reducing pipe type airflow drying device, so that the heat and mass transfer process of the silver powder wet material and the hot air is enhanced; according to the superfine silver powder drying device, the superfine silver powder materials are fully scattered and dried by fully exchanging heat, turbulent flow and dispersion with hot air, so that the problems of low drying efficiency, high energy consumption and easiness in caking in the drying process of the superfine silver powder are effectively solved, and the drying effect is remarkably improved.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the technical field of noble metal powder drying, and relates to an ultrafine silver powder airflow drying device. BACKGROUND

[0002] Ultrafine silver powder is a kind of noble metal powder widely used in electronic industry and has the largest consumption, and is one of the key functional materials for producing electronic touch screen, electronic connector, electronic component product and solar cell conductive silver paste.At present, the rapid development of electronic information and solar cell industry greatly promotes the market demand of ultrafine silver powder.The mainstream process method for preparing silver powder at present is liquid phase chemical reduction method, that is, taking silver nitrate as main raw material, adding dispersant and reducing agent, reducing Ag in solution into Ag, and then washing, filtering, drying and post-treating the product to obtain the final silver powder product. + Drying of ultrafine silver powder is a very important key step in the production process of silver powder, and the temperature and time in the drying process have a significant influence on the particle size of silver powder.Proper control of powder drying temperature (usually not higher than 100 DEG C) and time can reduce the particle size of silver powder and ensure that the product reaches the required particle size distribution;If not properly handled during the drying process, silver powder is prone to agglomeration, which affects subsequent use and product quality.Through reasonable drying process, such as cleaning with anhydrous ethanol and oleic acid mixed solution and then drying, electrostatic agglomeration of silver powder can be avoided during sieving, and the dispersibility and uniformity of silver powder can be ensured;Residual moisture in silver powder can be removed during the drying process to prevent moisture from adversely affecting product performance, such as reducing conductivity and increasing oxidation risk, and the dried silver powder has better stability and mechanical properties, such as hardness, adhesion, impact resistance and wear resistance, thereby ensuring the performance of the product in subsequent processing and use. Utility model content

[0003] The utility model discloses a kind of ultrafine silver powder airflow drying devices, to solve the technical problems of poor drying effect of the existing silver powder drying device.

[0004] In order to achieve the above purpose, the utility model adopts the following technical solutions to achieve the above purpose:

[0005] The utility model discloses a kind of ultrafine silver powder airflow drying devices, including air filter, heater, variable diameter pipe type airflow drying device, collection device, dust collector and induced draft fan;The air filter is connected with the inlet of heater;The outlet of heater and the inlet of variable diameter pipe type airflow drying device are connected;The outlet of variable diameter pipe type airflow drying device and collection device, dust collector and induced draft fan are sequentially connected;

[0006] The inner wall of the variable-diameter pipe type airflow drying device is provided with a plurality of convex variable-diameter modules; and the inner wall of the inlet of the variable-diameter pipe type airflow drying device is provided with a gas distribution plate.

[0007] Further, the heater is provided with a pipe path and a bent path; one side of the bent path is provided with a water vapor inlet, and the other side is provided with a water vapor outlet; one end of the pipe path is connected with the air filter, and the other end is connected with the inlet of the variable-diameter pipe type airflow drying device.

[0008] Further, the inlet of the variable-diameter pipe type airflow drying device is a hot air inlet; and the outlet of the variable-diameter pipe type airflow drying device is an airflow outlet.

[0009] Further, the variable-diameter pipe type airflow drying device is communicated with a feeder and a nozzle at the outer side wall above the gas distribution plate; and the feeder and the nozzle are connected with each other.

[0010] Further, the feeder and the nozzle are arranged at the outer side wall of the variable-diameter pipe type airflow drying device at 100mm-200mm above the gas distribution plate.

[0011] Further, the nozzle is a Venturi nozzle.

[0012] Further, the collecting device is a cyclone collector; and the dust collector is a bag-type dust collector.

[0013] Further, the outlet of the variable-diameter pipe type airflow drying device is connected with the collecting device, the dust collector and the induced draft fan in sequence, and further connected with a silencer.

[0014] Further, the ratio of the diameter D of the variable-diameter pipe type airflow drying device without the variable-diameter module to the diameter d of the variable-diameter module is 10: (5-7).

[0015] Further, the air filter is internally provided with a plurality of layers of filter screens.

[0016] Compared with the prior art, the variable-diameter pipe type airflow drying device has the following beneficial effects:

[0017] The utility model discloses a superfine silver powder airflow drying device, through setting up variable-diameter pipe type airflow drying device, because of the setting of gas distribution plate and variable-diameter module, let silver powder wet material evenly distribute and violent disturbance in hot airflow in variable-diameter pipe type airflow drying device, strengthen the heat transfer mass transfer process of silver powder wet material and hot air, and fully heat exchange, turbulent flow and dispersion are carried out with hot air, and superfine silver powder material is fully scattered and dried, effectively solve the low drying efficiency, big energy consumption, easy caking problem of superfine silver powder in the drying process, significantly improve the drying effect, and the device has the advantages of high heat transfer efficiency, short drying time, simple equipment, large processing capacity etc. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 It is the whole structure schematic view of superfine silver powder airflow drying device of the utility model;

[0019] Figure 2 It is the structure schematic view of variable diameter pipe type airflow drying device of the utility model;

[0020] Figure 3 It is the inner diameter entity view of variable diameter pipe type airflow drying device of the utility model.

[0021] Wherein: 1-air filter; 2-heater; 2-1, water vapor inlet; 2-2, water vapor outlet; 3-variable diameter pipe type airflow drying device; 3-1, hot air inlet; 3-2, airflow outlet; 3-3, feeder; 3-4, nozzle; 3-5, gas distribution plate; 3-6, variable diameter module; 4-collecting device; 5-dust collector; 6-induced draft fan; 7-silencer; D-drying pipe diameter; d-necking diameter. DETAILED DESCRIPTION

[0022] In order to make the person skilled in the art better understand the utility model scheme, the technical scheme in the embodiment of the utility model will be described clearly and completely below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is only a part of the embodiment of the utility model, not all. Based on the embodiment in the utility model, all other embodiments obtained by the person skilled in the art without creative labor should belong to the protection scope of the utility model.

[0023] It should be noted that the terms "first", "second" and the like in the specification and claims of the utility model and the above-mentioned drawings are used to distinguish similar objects, and do not have to be used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances, so that the embodiments of the utility model described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not have to be limited to the clearly listed steps or units, but can include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0024] The utility model will be described in further detail below in conjunction with the drawings:

[0025] Reference Figure 1The utility model discloses a superfine silver powder airflow drying device, including air filter 1, heater 2, variable diameter pipe type airflow drying device 3, collection device 4, dust catcher 5, air draught fan 6 and muffler 7, wherein, the outlet of air filter 1 is connected to the inlet of heater 2 through pipeline, the outlet of heater 2 is connected to the inlet of the bottom of variable diameter pipe type airflow drying device 3, the outlet of the top of variable diameter pipe type airflow drying device 3 is connected to the upper inlet of collection device 4, the top outlet of collection device 4 is connected to the middle inlet of dust catcher 5 through pipeline, the upper side outlet of dust catcher 5 is connected to the inlet of air draught fan 6 through pipeline, and the outlet of air draught fan 6 is connected with muffler 7.

[0026] As Figure 2 The inlet of variable diameter pipe type airflow drying device 3 is hot air inlet 3-1, and the outlet is airflow outlet 3-2, and the lower part of variable diameter pipe type airflow drying device 3 is provided with gas distribution plate 3-5, and feeder 3-3 and nozzle 3-4 are arranged at 100mm~200mm above gas distribution plate 3-5;Variable diameter pipe type airflow drying device 3 drying section is designed with 3 groups of variable diameter module 3-6, forms necking section;As Figure 3 The ratio of drying pipe diameter D and necking diameter d is 10: (5~7).

[0027] The heater 2 adopts steam heating mode, and air walks pipe process, and steam walks hook process, and the upper part of the heater 2 hook process is provided with water vapor inlet 2-1, and the bottom is provided with water vapor outlet 2-2.

[0028] The nozzle 3-4 is a venturi nozzle, and the venturi nozzle makes the silver powder material inlet in a negative pressure state, ensures that the silver powder material is smoothly sent into the pipe type airflow drying device, and prevents blockage.

[0029] The collection device 4 is a cyclone collector, and the dust catcher 5 is a bag-type dust collector.

[0030] Example 1

[0031] The utility model adopts steam heating mode, utilizes silver powder wet material and heat air in the pipe type airflow bed of variable diameter structure and carries out sufficient heat exchange, turbulence and dispersion, forms the new technology new method of superfine silver powder airflow drying, and the specific process method is as shown below:

[0032] The drying medium adopted is air, and after the air draught fan 6 is started, the inside of the superfine silver powder airflow drying device is in a negative pressure state.

[0033] Air first passes through the air filter 1 into the drying system, the air filter 1 is designed with 3 layers of filter screen to filter and purify the air, to prevent sundries in the air from entering the drying system; the filtered air enters the heater 2, the heater 2 is a tube-shell heat exchanger, adopts steam heating mode, the water vapor goes through the shell side, the water vapor inlet 2-1 is 180 DEG C, the temperature of the water vapor outlet 2-2 is adjusted by controlling the flow of the water vapor, the hot air temperature in the drying process is controlled within 110-150 DEG C; the hot air from the heater 2 enters the variable-diameter pipe type airflow drying device 3 from the water vapor outlet 2-2, the superfine silver powder wet material is sent into the variable-diameter pipe type airflow drying device 3 through the feeder 3-3, the variable-diameter pipe type airflow drying device 3 is provided with a gas distribution plate 3-5 at the lower part and three groups of variable-diameter modules 3-6 at the middle drying section, so that the heat and mass transfer of the superfine silver powder wet material and the hot air in the drying section are strengthened, the superfine silver powder after sufficient drying enters the collecting device 4 along with the airflow, the silver powder product after drying is obtained after passing through the collecting device 4, and is discharged from the lower part of the cyclone collector; the collection efficiency of the collecting device is 90-94%. The gas discharged from the outlet of the collecting device 4 still contains part of the silver powder particles with small particle size, considering the recovery of the silver powder particles and environmental protection reasons, the gas discharged from the outlet of the collecting device 4 enters the dust collector 5, the silver powder with small fineness is intercepted on the surface of the filter bag in the dust collector 5 and is discharged from the bottom outlet, in order to ensure that the silver powder recovery rate in the drying process is more than 99.9%, the mesh number of the filter bag is selected to be 900-1200 meshes, so that the fine silver powder particles in the airflow are fully recovered; and the wet hot gas is discharged from the upper part of the dust collector 5, passes through the induced draft fan 6 and the silencer 7 and is discharged to the outdoor, the dust content of the exhaust gas is controlled to be less than 10-20 mg, and the moisture content of the silver powder collected by the collecting device 4 and the dust collector 5 is less than or equal to 0.1%.

[0034] Example 2

[0035] 200kg silver powder wet material, water content 13.1%, drying temperature 115 DEG C, induced draft fan air volume 2000m 3 / h; the superfine silver powder airflow drying device disclosed by the utility model is used for drying, the cyclone collection efficiency is 92.10%, the bag type collection efficiency is 7.83%, the water content of the silver powder after drying is 0.03%, and the production process requirements are met.

[0036] Example 3

[0037] 200kg silver powder wet material, water content 18.5%, drying temperature 125 DEG C, induced draft fan air volume 2000m 3 / h; the superfine silver powder airflow drying device disclosed by the utility model is used for drying, the cyclone collection efficiency is 90.52%, the bag type collection efficiency is 9.39%, the water content of the silver powder after drying is 0.06%, and the production process requirements are met.

[0038] Example 4

[0039] 200 kg of silver powder wet material, water content 8.57%, drying temperature 105 DEG C, air volume of air fan 2000 m 3 / h; the superfine silver powder airflow drying device is used for drying, the cyclone collection efficiency is 93.68%, the bag type collection efficiency is 6.27%, the water content of silver powder after drying is 0.02%, and the production process requirements are met.

[0040] The superfine silver powder airflow drying device provided by the utility model, through the heater 2 provides hot air, and after purification through the air filter 1, it is ensured that the air entering the variable diameter pipe airflow drying device 3 is clean and has moderate temperature, which is beneficial to the uniform drying of the superfine silver powder; the design of the variable diameter module 3-6 increases the contact area and turbulence degree of airflow and silver powder, and improves the drying efficiency; the heater 2 adopts the tube and curved path design, allows water vapor to pass through the curved path for heat exchange, so as to heat the air in the tube path, and this design not only ensures the heating efficiency, but also is convenient for controlling the heating temperature, and meets different drying requirements; the gas distribution plate 3-5 is arranged at the inlet of the variable diameter pipe airflow drying device 3, and the hot air is uniformly distributed in the whole device, and the problems of local overheating or uneven drying are avoided; the ingenious design of the feeder 3-3 and the nozzle 3-5 enables the superfine silver powder to enter the drying device uniformly and continuously, and to be further dispersed through the nozzle 3-5, and the drying efficiency and product quality are improved.

[0041] The above content only illustrates the technical idea of the utility model, cannot limit the protection scope of the utility model, and any modification made on the basis of the technical scheme according to the technical idea of the utility model falls within the protection scope of the utility model claim.

Claims

1. An apparatus for drying ultra-fine silver powder in a gas stream, characterized by, It comprises an air filter (1), a heater (2), a variable-diameter pipe type airflow drying device (3), a collecting device (4), a dust collector (5) and an air blower (6); the air filter (1) is connected with the inlet of the heater (2); the outlet of the heater (2) is connected with the inlet of the variable-diameter pipe type airflow drying device (3); the outlet of the variable-diameter pipe type airflow drying device (3) is connected with the collecting device (4), the dust collector (5) and the air blower (6) in sequence. The inner wall of the variable-diameter pipe type airflow drying device (3) is provided with a plurality of convex variable-diameter modules (3-6); the inner wall of the inlet of the variable-diameter pipe type airflow drying device (3) is provided with a gas distribution plate (3-5).

2. The superfine silver powder airflow drying device according to claim 1, characterized in that, The heater (2) is provided with a tube path and a curved path; one side of the curved path is provided with a water vapor inlet (2-1), and the other side is provided with a water vapor outlet (2-2); one end of the tube path is connected with the air filter (1), and the other end is connected with the inlet of the variable-diameter pipe type airflow drying device (3).

3. The superfine silver powder airflow drying device according to claim 1, characterized in that, The inlet of the variable-diameter pipe type airflow drying device (3) is a hot air inlet (3-1); the outlet of the variable-diameter pipe type airflow drying device (3) is an airflow outlet (3-2).

4. The superfine silver powder air flow drying device according to claim 1, characterized in that, The variable-diameter pipe type airflow drying device (3) is communicated with a feeder (3-3) and a nozzle (3-4) on the outer side wall of the upper part of the gas distribution plate (3-5); the feeder (3-3) and the nozzle (3-4) are connected with each other.

5. The superfine silver powder air flow drying device according to claim 4, characterized in that, The feeder (3-3) and the nozzle (3-4) are arranged on the outer side wall of the variable-diameter pipe type airflow drying device (3) at 100mm-200mm of the upper part of the gas distribution plate (3-5).

6. The super-fine silver powder air flow drying device according to claim 4, characterized in that, The nozzle (3-4) is a Venturi nozzle.

7. The superfine silver powder air flow drying device according to claim 1, characterized in that, The collecting device (4) is a cyclone collector; the dust collector (5) is a bag-type dust collector.

8. The superfine silver powder air flow drying device according to claim 1, characterized in that, The outlet of the variable-diameter pipe type airflow drying device (3) is connected with the collecting device (4), the dust collector (5) and the air blower (6) in sequence, and further connected with a silencer (7).

9. The superfine silver powder air flow drying device according to claim 1, characterized in that, The ratio of the diameter of the variable-diameter pipe type airflow drying device (3) without the variable-diameter module (3-6) to the diameter of the variable-diameter module (3-6) is 10: (5-7).

10. The superfine silver powder air flow drying device according to claim 1, characterized in that, The air filter (1) is internally provided with a plurality of layers of filter screens.

Images