Ultrahigh-purity polyolefin powder preparation device

Abstract

The utility model relates to an ultra-pure polyolefin powder preparation device which comprises a crushing unit and a screening unit, and the crushing unit comprises a pulverizer provided with a grinding part; the screening unit comprises a cyclone separator, a vibrating screen and a magnetic filter arranged at the discharging end of the vibrating screen. A discharge port of the flour mill is communicated with a feed port of the cyclone separator through a feeding pipeline; and a material return port of the vibrating screen is communicated with the flour mill through a material return pipeline and is used for returning screen residues of the vibrating screen to the flour mill. According to the device, large-particle polyolefin materials are crushed, screened and demagnetized, and the utilization rate of the materials and the added value of products are improved.

Description

Technical Field

[0001] This utility model relates to the field of ultra-high purity polyolefin preparation technology, specifically to an ultra-high purity polyolefin powder preparation device. Background Technology

[0002] Polyolefins, as a core raw material in the field of polymer materials, are widely used in injection molding, film preparation, and pipe production. The particle size uniformity of polyolefin raw materials directly affects the melt flowability, processing stability, and mechanical properties of the final product. Therefore, preparing high-quality polyolefin powder with controllable particle size distribution is one of the core goals of the industry. Currently, vibrating screening is a common process for particle size classification of polyolefin powder in industrial production. However, the traditional method for handling large particles generated during screening is to sell them directly as low-value-added products, which cannot fully tap the product's value. Therefore, developing a specialized device that can be efficiently coupled with a vibrating screening system to achieve directional grinding and crushing of large particles and precisely control the particle size distribution of the processed powder has become a key technological bottleneck for improving the added value of polyolefin powder production and promoting green and efficient manufacturing in the industry.

[0003] Chinese patent CN220446923U discloses a polyolefin material separation and recycling device, including a silo, a crushing mechanism, a powder vibration screening mechanism, a screening mechanism, a removable screen plate, a block material conveying pipe, a waste collection box, and a powder discharge tank. The silo is connected to the crushing mechanism; the crushing mechanism is connected to the powder vibration screening mechanism; the powder vibration screening mechanism is connected to the screening mechanism and the powder discharge tank respectively; the screening mechanism is connected to the waste collection box through the block material conveying pipe, and the screening mechanism is also connected to the powder discharge tank; one end of the removable screen plate passes through the side wall of the screening mechanism, and the other end of the removable screen plate is connected to the block material conveying pipe; the screening mechanism is used to transport the second polyolefin block material obtained by screening through the removable screen plate to the waste collection box, and to transport the second powder material to the powder discharge tank. This device enables the recycling of powder from polyolefin lumps, reducing the loss of qualified powder and avoiding economic losses to some extent. It also achieves effective separation of powder and lumps through multiple screening holes of a removable sieve plate. However, it cannot be used to produce ultra-high purity polyolefin powder.

[0004] Ultra-high purity polyolefins are critical basic materials, belonging to a class of materials with extremely high purity and ultra-low metal ion content. Taking polyethylene as an example, ultra-high purity polyethylene can serve as a key basic material in the semiconductor industry chain. It is a core raw material for applications such as ultrapure water filtration, ultrapure reagent delivery pipelines, and storage containers used in semiconductor manufacturing. It directly determines the stability and service life of ultrapure water systems and plays an irreplaceable role in ensuring the yield of chip manufacturing in the semiconductor industry. Although existing polyolefin powder preparation equipment can achieve particle size control to a certain extent, it lacks impurity removal and cleanliness control for ultra-high purity materials, resulting in insufficient product purity. In addition, traditional crushing and sieving processes may introduce metal contamination or organic residues, making it difficult to meet production requirements. Therefore, it is urgent to integrate efficient purification, precise classification, and end-to-end cleanliness control technologies into existing equipment to achieve the industrial-scale preparation of ultra-high purity polyethylene. Utility Model Content

[0005] The purpose of this invention is to provide an ultra-high purity polyolefin powder preparation device to solve the above-mentioned problems.

[0006] The objective of this utility model is achieved through the following technical solution:

[0007] An apparatus for preparing ultra-high purity polyolefin powder includes a pulverizing unit and a sieving unit. The pulverizing unit includes a grinding mill equipped with grinding components. The sieving unit includes a cyclone separator, a vibrating screen, and a magnetic filter located at the discharge end of the vibrating screen. The discharge port of the grinding mill is connected to the inlet of the cyclone separator via a feeding pipeline. The return port of the vibrating screen is connected to the grinding mill via a return pipeline for returning the residue from the vibrating screen to the grinding mill.

[0008] As a preferred technical solution, the upper part of the grinding mill is connected to a feed hopper, and the feed hopper can be used to send large particles of material to be processed from upstream to the grinding mill via a feeder.

[0009] As a preferred technical solution, the inner surfaces of the feed hopper, feeding pipeline, and return pipeline are all coated with polytetrafluoroethylene (PTFE). By coating the inner walls with PTFE, its extremely low surface energy and coefficient of friction create an ultra-smooth surface, reducing the residue of high-viscosity polyolefin materials, lowering the amount of residue per conveying, and simultaneously preventing ion migration contamination caused by contact between metal pipelines and materials, thus reducing the metal impurity content of the product.

[0010] As a preferred technical solution, the grinding chamber and grinding components of the mill are made of zirconia ceramic or silicon nitride material. Non-metallic wear-resistant materials are used to replace traditional metal parts, eliminating the introduction of metal ions such as iron and chromium during the grinding process.

[0011] As a preferred technical solution, the grinding mill is equipped with a variable frequency speed control motor and is connected to a cooling system. The cooling system can be a water cooling system or a liquid nitrogen cooling system to maintain the grinding at a low temperature and prevent the material from plasticizing at a high temperature.

[0012] As a preferred technical solution, a rotary valve is provided between the cyclone separator and the vibrating screen to achieve continuous and stable feeding, avoid material accumulation or flow interruption, ensure continuous operation of the screening unit, and accurately control the feeding amount to match the processing capacity of the vibrating screen.

[0013] As a preferred technical solution, the upper part of the cyclone separator is connected to a vacuum pump through an air extraction pipeline, and the outlet of the vacuum pump is connected to a bag filter to filter the discharged gas and avoid dust pollution.

[0014] As a preferred technical solution, the vibrating screen adopts a detachable and replaceable non-metallic woven screen mesh, which reduces the metal content of the product. The discharge port of the vibrating screen is connected to the inlet flange of the magnetic filter.

[0015] As a preferred technical solution, the magnetic filter employs an electrically powered automatic demagnetizer, which contains a rotatable electromagnet array and an automatic impurity removal mechanism with a scraper at the bottom. The magnetic induction intensity on the surface of the electromagnet array is 1.2-1.5T, improving the capture efficiency of small-diameter metal particles.

[0016] As a preferred technical solution, the magnetic filter is connected downstream to a collection container.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] This device performs controlled-size crushing, sieving, and demagnetization of large polyolefin particles. Through a process of "mechanical crushing—pneumatic conveying—sieving and sorting—electromagnetic purification," purified fine particles with suitable particle size are collected. This achieves grinding, sieving, and purification of the large particles after sieving, improving material utilization and product added value, and meeting the demand for high-quality polyolefins in high-end manufacturing. Furthermore, this device eliminates the source of metal contamination with a non-metallic contact system, and, combined with a rotary valve for precise feeding and a return circulation system, effectively reduces the content of metal impurities and improves the particle size qualification rate, meeting the requirements of polyolefin materials for ultra-clean, fine-particle-size powder. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of the device;

[0020] In the diagram: 1-Grinding mill; 2-Feeding pipeline; 3-Feeding hopper; 4-Cyclone separator; 5-Rotary valve; 6-Vibrating screen; 7-Extraction pipeline; 8-Vacuum pump; 9-Bag filter; 10-Return pipeline; 11-Magnetic filter; 12-Collection container. Detailed Implementation

[0021] The present invention will now be described in detail with reference to the accompanying drawings. Any aspects of the present invention not described in detail are technical solutions already disclosed in the field.

[0022] Reference Figure 1 This invention provides an ultra-high purity polyolefin powder preparation device. The device includes a crushing unit for crushing large particles and a screening unit for screening the material. The discharge end of the crushing unit is connected to the feed end of the screening unit via a pipeline. A return pipeline for returning the sieved residue to the crushing unit is provided between the crushing unit and the screening unit. In a specific embodiment, the crushing unit uses a fine grinding mill 1, equipped with a variable frequency speed-regulating motor to achieve precise control of the particle size range of 10-200 mesh. The crushing unit is equipped with a feed hopper 3, which can be fed to the crushing unit by a feeder. In a preferred embodiment, the grinding mill 1 is also connected to a cooling system to prevent the grinding mill temperature from rising during operation. The screening unit uses a vibrating screen 6. The screen mesh of the vibrating screen 6 is replaceable and adjustable, and the screen aperture can be 40 mesh as needed. The screened material from the vibrating screen 6 is discharged through the outlet and then passes through a magnetic filter 11 for demagnetization filtration to remove residual metal particles from the powder. Finally, it is collected and packaged in a collection container 12 or sent to downstream processes. The residue from the vibrating screen 6 is returned to the crushing unit for further crushing through a return pipe 10. A cyclone separator 4 is installed at the top of the screening unit. The crushed material is sent to the cyclone separator 4 through the feeding pipe 2. A rotary valve 5 is installed at the lower end of the cyclone separator 4. The solid powder separated by the cyclone separator 4 is sent to the vibrating screen 6 for screening through the rotary valve 5 at the bottom. The upper end of the cyclone separator 4 is connected to a vacuum pump 8 through an exhaust pipe 7. The gas components are drawn away by the vacuum pump 8, and the outlet of the vacuum pump 8 is connected to a bag filter 9. The gas components are discharged after being filtered by the bag filter 9.

[0023] To prepare ultra-high purity polyolefin powder, the grinding chamber and grinding components of the mill 1 are made of zirconia ceramic or silicon nitride to reduce metal ion precipitation and contamination. The inner walls of the feed hopper 3, feeding pipe 2, and return pipe 10 are coated with polytetrafluoroethylene (PTFE) with a surface roughness ≤0.2μm to reduce material adhesion and impurity adsorption. Furthermore, the screen of the vibrating screen 6 is made of non-metallic woven mesh (such as high-strength polyester fiber), and a magnetic filter 11 is connected to the outlet of the vibrating screen 6 for a final demagnetization process to minimize metal impurities in the powder and ensure the polyolefin powder reaches ultra-clean, high-purity standards. Specifically, the magnetic filter 11 can be an electrically powered automatic demagnetizer, which can automatically clean itself without manual intervention.

[0024] Taking polyethylene as an example, the working process is as follows: large polyethylene particles from the upstream process are fed to the feed hopper 3 by the feeder, and then enter the grinding mill 1 for crushing. The crushed fine particles are sent to the cyclone separator 4 through the feed pipe 2 for cyclone gas-solid separation. The gas components are removed by the vacuum pump 8 connected to the exhaust pipe 7, and then discharged from the system after being filtered by the bag filter 9. The solid particles are collected at the bottom of the cyclone separator 4 and enter the vibrating screen 6 through the rotary valve 5 for screening. The screened material of the vibrating screen 6 is discharged through the outlet as qualified material, and then filtered through the magnetic filter 11 to remove residual metal particles. Finally, it is collected through the collection container 12. The screen residue of the vibrating screen 6 is returned to the grinding mill 1 through the return pipe 10 as unqualified material for crushing again until all particles meet the standard.

[0025] In a preferred embodiment, this device employs a three-stage purification architecture. A cyclone separator 4 performs primary gas-solid separation, while the lower rotary valve 5 utilizes an airtight structure, combining airlock and quantitative discharge functions. A vibrating screen 6 performs precision sieving, featuring a multi-segment polyester screen that generates composite vibration via an exciter, resulting in high sieving efficiency. A magnetic filter 11 uses an electromagnet array design with a surface magnetic induction intensity ≥1.2T, capable of capturing fine-sized Fe, Ni, and other metal particles. A self-cleaning scraper system enables continuous automatic impurity removal. This device performs controlled-size crushing, sieving, and demagnetization of large-particle polyolefin materials. Qualified purified fine particles are continuously collected, achieving grinding, sieving, and purification of the sieved large particles, improving material utilization and product added value, and meeting the demand for high-quality polyolefins in high-end manufacturing.

[0026] The above description of the embodiments is provided to enable those skilled in the art to understand and use the utility model. It will be apparent to those skilled in the art that various modifications can be easily made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present utility model is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present utility model without departing from its scope should be within the protection scope of the present utility model.

Claims

1. A device for preparing ultra-high purity polyolefin powder, characterized in that, Includes a crushing unit and a screening unit; The pulverizing unit includes a grinding mill (1) equipped with grinding components; The screening unit includes a cyclone separator (4), a vibrating screen (6), and a magnetic filter (11) located at the discharge end of the vibrating screen (6); The discharge port of the grinding mill (1) is connected to the inlet of the cyclone separator (4) through a feeding pipe (2); The return port of the vibrating screen (6) is connected to the grinding mill (1) through the return pipe (10) to return the residue of the vibrating screen (6) to the grinding mill (1).

2. The ultra-high purity polyolefin powder preparation device according to claim 1, characterized in that, The upper part of the grinding mill (1) is connected to the feed hopper (3).

3. The ultra-high purity polyolefin powder preparation device according to claim 2, characterized in that, The inner surfaces of the feed hopper (3), the feeding pipe (2) and the return pipe (10) are all coated with polytetrafluoroethylene.

4. The apparatus for preparing ultra-high purity polyolefin powder according to claim 1, characterized in that, The grinding chamber and grinding components of the mill (1) are made of zirconium oxide ceramic or silicon nitride material.

5. The apparatus for preparing ultra-high purity polyolefin powder according to claim 1, characterized in that, The grinding mill (1) is equipped with a variable frequency speed control motor and is connected to a cooling system.

6. The apparatus for preparing ultra-high purity polyolefin powder according to claim 1, characterized in that, A rotary valve (5) is provided between the cyclone separator (4) and the vibrating screen (6).

7. The apparatus for preparing ultra-high purity polyolefin powder according to claim 1, characterized in that, The upper part of the cyclone separator (4) is connected to a vacuum pump (8) through an air extraction pipe (7), and the outlet of the vacuum pump (8) is connected to a bag filter (9).

8. The apparatus for preparing ultra-high purity polyolefin powder according to claim 1, characterized in that, The vibrating screen (6) uses a detachable and replaceable non-metallic woven screen, and its discharge port is connected to the feed port flange of the magnetic filter (11).

9. The apparatus for preparing ultra-high purity polyolefin powder according to claim 1, characterized in that, The magnetic filter (11) is an electric automatic demagnetizer with a rotatable electromagnet array inside and an automatic impurity removal mechanism with a scraper at the bottom.

10. The apparatus for preparing ultra-high purity polyolefin powder according to claim 1, characterized in that, The magnetic filter (11) is connected downstream to the collection container (12).

Images