A process for reducing dust in the production of bright silver powder

Abstract

This invention provides a process for reducing dust during the production of bright silver powder. The invention relates to the field of powder processing technology and includes the following steps: S1, selecting stainless steel balls with a diameter of 3-10 mm as the grinding media, with a ball-to-powder ratio of 10:1-3, and using a planetary ball mill at a speed of 200-300 r / min for 12-24 hours, controlling the temperature at 30-40℃; S2, adding solvent to the ball milling jar, with a silver powder to solvent ratio of 1:2-3, continuing ball milling for 2 minutes, and then reducing the speed to 100 r / min. S1. The material is milled at -150 r / min, and solvent is sprayed into the ball mill using a solvent addition spray gun; S2. The material is sieved through a vibrating screen with a mesh size of 10-40 mesh, and dust is collected during the sieving process using a dust collection device; S3. The silver powder mixture that has passed through the sieve is poured into a filter bucket and naturally filtered for 5-12 hours using an 800-1000 mesh filter screen; S4. The material is dried at 30-40℃ for 12-18 hours, and the thickness of the silver filter cake does not exceed 2 cm; S5. The material is then sieved through a 100-300 mesh ultrasonic vibrating screen. This invention can effectively reduce dust during the grinding process of bright silver powder, prevent dust overflow, and greatly improve the production working environment.

Description

Technical Field

[0001] This invention relates to the field of powder processing technology, and in particular to a process for reducing dust during the production of bright silver powder. Background Technology

[0002] Bright silver powder is the main conductive filler in polymer silver paste. It is used in the production and preparation of electronic materials and devices such as conductive adhesives, touch screens and membrane switches. It has a wide range of applications in the fields of electronics, communications and photovoltaics. With the rapid development of the domestic electronics, communications and clean energy industries, its usage is increasing.

[0003] Bright silver powder is generally produced using a dry mechanical ball milling process. The main process route is ball milling, ball powder separation, cleaning, drying, sieving, inspection and packaging. The ball powder separation process is mostly done manually, which generates a lot of dust. Developing a process that meets product quality and technical requirements while minimizing dust generation is one of the important technical means to improve the silver recovery rate and improve the working environment. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a process for reducing dust during the production of bright silver powder. This invention can effectively reduce dust during the grinding process of bright silver powder, prevent dust overflow, and greatly improve the production environment.

[0005] To solve the above problems, the technical solution adopted by the present invention is as follows: A process for reducing dust during the production of bright silver powder includes the following steps: S1, selecting stainless steel balls with a diameter of 3-10 mm as the grinding media, with a ball-to-material ratio of 10:1-3, and using a planetary ball mill at a speed of 200-300 r / min for 12-24 hours, controlling the temperature at 30-40℃; S2, adding solvent to the ball milling jar, with a silver powder to solvent ratio of 1:2-3, continuing ball milling for 2 minutes, reducing the speed to 100-150 r / min, and using a solvent... S3. Apply solvent to the ball mill using an additive spray gun; S4. Sieve the material through a vibrating screen with a mesh size of 10-40, and collect the dust using a dust collection device during the sieving process; S5. Pour the silver powder mixture that has passed through the sieve into a filter bucket and filter naturally for 5-12 hours using an 800-1000 mesh filter screen; S6. Dry at 30-40℃ for 12-18 hours, ensuring the silver filter cake thickness does not exceed 2cm; S7. Sieve through a 100-300 mesh ultrasonic vibrating screen, and collect the silver powder that has passed through the sieve in a sealed container.

[0006] Dry ball milling optimizes the ball-to-material ratio and process parameters, improving silver powder grinding efficiency and reducing energy consumption and wear. In the wet ball milling stage, solvent is precisely added using a solvent spray gun, significantly reducing dust emissions and improving the production environment. Staged process control (ball milling, sieving, filtration, drying, etc.) ensures uniform silver powder particle size and high purity, meeting industrial requirements. Ultrasonic vibrating screens reduce clogging risks, improve sieving efficiency, and guarantee stable quality of the finished silver powder.

[0007] Preferably, the stainless steel balls are mixed in different diameter ratios, and the purity of the raw silver powder is above 99.9%, with a particle size distribution of 1-5μm.

[0008] Mixed-diameter stainless steel balls improve grinding efficiency and make silver powder particles more uniform; high purity (above 99.9%) and specific particle size (1-5μm) of raw silver powder ensure excellent performance of the final product.

[0009] Preferably, the solvent adding spray gun includes a positioning cylinder, a nozzle, and a spraying device. The nozzle is connected to a drive motor via a telescopic end, which can deflect and spray the solvent so that the solvent is sprayed in a fan-shaped area.

[0010] The above methods can expand the area of ​​solvent spraying, allowing the solvent and silver powder to mix more effectively and thoroughly, while also increasing the humidity inside the ball mill and reducing dust generation.

[0011] Preferably, the spraying device includes a spray base and a spray hole. The spray base is located inside the feeding channel and continuously generates water mist to prevent dust from overflowing.

[0012] By setting up the above structure, dust spillage can be effectively prevented, greatly improving the working environment.

[0013] Preferably, the positioning cylinder is provided with a drive piston and a storage chamber, and the solvent is pumped into the storage chamber through a delivery pipeline and sprayed out from the nozzle and spraying device.

[0014] With the above structural design, there is no need to install a long delivery hose on the outside of the nozzle 500. The liquid solvent can be delivered by utilizing the internal structure of the positioning cylinder 100 and the telescopic end 600, ensuring the stability of normal solvent pumping. This is especially suitable for the complex environment around the ball mill.

[0015] Preferably, the screen of the vibrating screen is made of stainless steel, and the installation level error does not exceed ±0.5mm.

[0016] Preferably, the filter cartridge is made of corrosion-resistant plastic and the filter screen is made of polyester fiber.

[0017] Preferably, a forced-air drying oven is used, with temperature fluctuations not exceeding ±1℃, and the temperature is monitored in real time by a temperature sensor.

[0018] Preferably, the ultrasonic power and frequency of the ultrasonic vibrating screen are matched with the vibration parameters, and the coarse particles on the screen are returned to the ball milling process.

[0019] Preferably, both the dry ball milling stage and the wet ball milling stage employ a circulating water cooling system to control the temperature.

[0020] The beneficial effects of this invention are as follows: Compared with existing technologies, the process of combining dry and wet ball milling, ball powder separation, filtration, drying, sieving, inspection and packaging can effectively reduce dust during the grinding of bright silver powder, prevent dust overflow, and greatly improve the production environment. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the three-dimensional structure of the solvent addition spray gun of the present invention.

[0022] Figure 2 For the present invention Figure 1 A schematic diagram of the main structure.

[0023] Figure 3 For the present invention Figure 2 A magnified structural diagram at point A.

[0024] Figure 4 For the present invention Figure 2 A magnified structural diagram at point B.

[0025] In the figure: 100, positioning cylinder; 1001, storage chamber; 110, first drive rod; 120, second drive rod; 200, spraying device; 210, spraying base; 220, spraying hole; 300, delivery pipe; 400, connecting hose; 500, nozzle; 600, telescopic end; 700, drive motor; 710, drive shaft. Detailed Implementation

[0026] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0027] A process for reducing dust during the production of bright silver powder includes the following steps: Phase 1: Dry Ball Milling Phase Ball material selection and proportioning High-hardness and wear-resistant stainless steel balls are selected as the grinding media, with a diameter range of 3-10mm. Stainless steel balls of different diameters are mixed in a certain proportion to improve ball milling efficiency. The ball-to-material ratio is strictly controlled at 10:1-3. This ratio has been verified by a large number of experiments. Within this range, the silver powder can be fully ground during the ball milling process, while avoiding energy waste and accelerated wear of the ball mill jar caused by an excessively large ball-to-material ratio.

[0028] The raw material silver powder should be high-purity silver powder with a purity of 99.9% or higher and a particle size distribution between 1-5μm to ensure the quality of the final product.

[0029] Ball mill equipment and parameters Using a planetary ball mill with precise temperature and speed control, this equipment provides a stable and efficient milling environment. The milling time is set to 12-24 hours, and the mill speed is controlled at 200-300 r / min. During the milling process, the temperature inside the milling jar is monitored in real time, and a circulating water cooling system is used to control the temperature at 30-40℃ to prevent silver powder oxidation or agglomeration due to excessive temperature.

[0030] Phase Two: Wet Ball Milling Phase Solvent selection and addition Anhydrous ethanol is preferred as the solvent because it has good solubility and volatility and is non-corrosive to silver powder. The ratio of silver powder to solvent should be strictly controlled at 1:2-3. After accurately measuring the required amount of solvent, add it slowly into the ball mill jar to avoid solvent splashing and silver powder agglomeration.

[0031] Ball mill operation and control After adding the solvent, continue ball milling for 2 minutes. At this time, the speed of the ball mill should be appropriately reduced to 100-150 r / min to ensure that the solvent and silver powder are fully mixed, and to reduce the impact force during the ball milling process to prevent the silver powder from being excessively broken. During the ball milling process, turn on the stirring device of the ball mill jar to ensure that the material is mixed evenly.

[0032] In the wet ball milling stage, a solvent addition spray gun is used, including a positioning cylinder 100. The positioning cylinder 100 has a hollow interior design, and a nozzle 500 is provided at the first end of the positioning cylinder 100. The nozzle 500 can spray solvent into the ball mill, which can mix with the material in the ball mill and avoid generating too much dust.

[0033] The spray gun here can extend from the horizontal axis of the ball mill into the inside of the ball mill to spray out the solvent. The spray gun also includes a telescopic end 600, which is rotatably connected to the nozzle 500. The nozzle 500 can rotate relative to the telescopic end 600. A drive motor 700 is installed on the outside of the telescopic end 600 to drive and control the deflection of the nozzle 500. By controlling the deflection of the nozzle 500, the solvent sprayed by the nozzle 500 can be sprayed in a fan-shaped area, which can spray the solvent to various positions inside the ball mill, improve the mixing effect of solvent and powder, improve the overall mixing efficiency, and greatly shorten the overall processing time.

[0034] A spray device 200 is also installed on the outside of the positioning cylinder 100. The spray device 200 can continuously generate atomized water mist, which can create a barrier around the positioning cylinder 100 to prevent powder from overflowing from there. The spray device 200 includes a spray base 210 and a spray hole 220. The spray base 210 is installed on the side close to the nozzle 500. During use, the spray base 210 is located in the feeding channel and does not enter the ball mill. It can continuously generate water mist within a small area to prevent dust from overflowing.

[0035] The positioning cylinder 100 is also sealed and slidably connected to a drive piston. A first drive rod 110 is fixed on the first side of the drive piston, and a second drive rod 120 is fixed on the second side. The second drive rod 120 is connected to an external power source to control the horizontal movement of the drive piston. The end of the first drive rod 110 passes through the positioning cylinder 100 and is sealed and slidably connected to it. The end of the first drive rod 110 is connected to the telescopic end 600, which can drive the telescopic end 600 to drive the nozzle 500 to move linearly.

[0036] A storage chamber 1001 is formed between the drive piston and the inner wall of the positioning cylinder 100. The storage chamber 1001 can store liquid solvent. A delivery pipe 300 is installed on the outside of the storage chamber 1001. The delivery pipe 300 can pump the solvent into the storage chamber 1001. Finally, the solvent can be sprayed out from the nozzle 500 and the spray device 200. The solvent sprayed from the nozzle 500 can directly enter the ball mill. The solvent sprayed from the spray device 200 can form a spray to form an isolation barrier to prevent dust from overflowing.

[0037] The spray device 200 and the nozzle 500 are connected to the storage chamber 1001. While the solvent is being pumped into the storage chamber 1001, the nozzle 500 at the end can spray out the solvent, and the spray device 200 can atomize and generate water mist to form a barrier.

[0038] The telescopic end 600 can be a hollow pipe. The nozzle 500 is connected to the telescopic end 600 via a connecting hose 400. The telescopic end 600 is connected to the storage chamber 1001. With the above structural design, there is no need to install a long delivery hose on the outside of the nozzle 500. The liquid solvent can be delivered using the positioning cylinder 100 and the internal structure of the telescopic end 600, ensuring the stability of normal solvent pumping. This is especially suitable for the complex environment around the ball mill.

[0039] Phase 3: Powder Separation Phase Vibrating Screen Selection and Installation Select a vibrating screen with good vibration performance and screening efficiency, with a screen mesh size of 10 to 40 mesh; the screen material should be stainless steel, which has high strength and corrosion resistance; when installing the vibrating screen, ensure that its levelness error does not exceed ±0.5mm to ensure the uniformity of screening effect.

[0040] Material transfer and screening After opening the ball mill jar, the material is transferred to the vibrating screen using sealed pipes and conveying equipment to reduce dust during the transfer process. During the screening process, the amplitude and frequency of the vibrating screen are adjusted to ensure that the material is evenly distributed on the screen surface, thereby improving screening efficiency. At the same time, a dust collection device is installed above the vibrating screen to collect the small amount of dust generated during the screening process, further improving the working environment.

[0041] Phase Four: Filtering Phase Filter canister and filter screen selection The filter housing is made of corrosion-resistant plastic and features a rationally designed internal structure for easy material loading, unloading, and cleaning. The filter screen is an 800-1000 mesh polyester fiber screen, which offers excellent filtration performance and mechanical strength. When installing the filter screen, ensure a tight seal between the screen and the filter housing to prevent material leakage.

[0042] Filtering Operation and Control Slowly pour the sieved silver powder mixture into the filter bucket for natural filtration. The filtration time should be controlled between 5 and 12 hours, and can be adjusted appropriately according to the properties of the material and the filtration process. During filtration, regularly check the liquid level in the filter bucket and the condition of the filter screen. If any blockage is found, clean or replace the filter screen promptly.

[0043] Phase 5: Drying Phase Oven selection and parameter settings A forced-air drying oven was selected, which has good temperature uniformity and ventilation performance. The drying temperature was set at 30-40℃ for 12-18 hours. During the drying process, the temperature inside the oven was monitored in real time by a temperature sensor to ensure that the temperature fluctuation range did not exceed ±1℃. At the same time, the blower speed was adjusted to ensure good air circulation inside the oven and accelerate solvent evaporation.

[0044] Monitoring of silver filter cake placement and drying process Spread the silver filter cake evenly on the tray inside the oven, with a thickness not exceeding 2cm, to ensure uniform drying effect. During the drying process, observe the state of the silver filter cake regularly, such as its color and shape, and adjust the drying parameters promptly if any abnormalities are found.

[0045] Phase Six: Screening Phase Ultrasonic Vibrating Screen Selection and Parameter Setting Select a vibrating screen equipped with an ultrasonic generator, with a screen mesh size of 100-300 mesh. Ultrasonic vibrating screens effectively prevent silver powder from clogging the screen, improving screening efficiency. Adjust the power and frequency of the ultrasonic waves to match the vibration parameters of the vibrating screen to achieve the best screening effect.

[0046] Sieving operation and finished product collection The dried silver powder is slowly added to an ultrasonic vibrating screen for sieving. During the sieving process, the feeding speed is controlled to avoid material accumulation. The coarse silver powder particles on the screen can be returned to the ball mill for re-grinding, and the finished silver powder under the screen is collected in a sealed container to prevent secondary contamination.

[0047] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A process for reducing dust in the production of bright silver powder, characterized by, Includes the following steps: S1. Select stainless steel balls with a diameter of 3-10mm as the grinding media, with a ball-to-material ratio of 10:1-3. Use a planetary ball mill at a speed of 200-300r / min for 12-24 hours, and control the temperature at 30-40℃. S2. Add solvent to the ball mill jar, with a silver powder to solvent ratio of 1:2-3. Continue ball milling for 2 minutes, reduce the rotation speed to 100-150 r / min, and use a solvent addition spray gun to spray the solvent into the ball mill. S3. Materials are screened using a vibrating screen with a mesh size of 10-40, and dust is collected using a dust collection device during the screening process. S4. Pour the sieved silver powder mixture into a filter bucket and filter naturally for 5-12 hours using an 800-1000 mesh filter. S5. Dry at 30-40℃ for 12-18 hours, with the silver filter cake thickness not exceeding 2cm; S6. Use a 100-300 mesh ultrasonic vibrating screen to sieve the silver powder, and seal and collect the silver powder that passes through the sieve. The solvent adding spray gun includes a positioning cylinder (100), a nozzle (500) and a spraying device (200). The nozzle (500) is connected to a drive motor (700) via a telescopic end (600) and can deflect and spray solvent to make the solvent spray in a fan-shaped area. The spraying device (200) includes a spray base (210) and a spray hole (220). The spray base (210) is located in the feeding channel and continuously generates water mist to prevent dust from overflowing. The positioning cylinder (100) is equipped with a driving piston and a storage chamber (1001). The spraying device and the nozzle are connected to the storage chamber. The solvent is pumped into the storage chamber (1001) through the delivery pipe (300) and sprayed out from the nozzle (500) and the spraying device (200).

2. The process according to claim 1, characterized in that, Stainless steel balls are mixed in proportions of different diameters. The purity of the raw silver powder is over 99.9%, and the particle size distribution is 1-5μm.

3. The process of claim 1, wherein, In step S3, the screen of the vibrating screen is made of stainless steel, and the installation level error does not exceed ±0.5mm.

4. The process of claim 1, wherein, In step S4, the filter canister is made of corrosion-resistant plastic, and the filter screen is made of polyester fiber.

5. The process of claim 1, wherein, In step S5, a forced-air drying oven is used, with temperature fluctuations not exceeding ±1℃, and the temperature is monitored in real time by a temperature sensor.

6. The process of claim 1, wherein, In step S3, the ultrasonic power and frequency of the ultrasonic vibrating screen are matched with the vibration parameters, and the coarse particles on the screen are returned to the ball milling process.

7. The process of claim 1, wherein, Both the dry ball milling stage and the wet ball milling stage use a circulating water cooling system to control the temperature.

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