High-purity alumina slurry treatment method and treatment device

Abstract

The invention discloses a high-purity aluminum oxide slurry treatment method and device. The method comprises the following steps: a, conveying high-purity aluminum oxide slurry to screening equipment through a pipeline; b, the screened slurry flows into a material receiving groove; c, the slurry flows into first iron removal equipment from a discharging opening in the lower end of the material receiving groove; d, conveying to filtering equipment through a diaphragm pump; e, enabling the filtered slurry to pass through second iron removal equipment; and f, defoaming the slurry, and conveying the slurry to a storage tank. Efficient screening, impurity removal and filtering of the high-purity aluminum oxide slurry are achieved. According to the technical means, high purity and high insulativity of the slurry in the production process are ensured, meanwhile, the production cost is reduced, the production stability is improved, and therefore high-quality products with competitiveness in the semiconductor material production field are obtained.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor manufacturing technology, and in particular to a high-purity aluminum oxide slurry processing method and processing device. Background Art

[0002] High-purity alumina ceramics not only have the advantages of high insulation, high thermal insulation, corrosion resistance, and high hardness, but also have a wide source and low price cost. It is currently one of the world's largest produced and most widely used ceramic materials, and is widely used in semiconductors, mechanical processing, chemical industry, aerospace and other fields.

[0003] High-purity alumina products have very high purity requirements. The metal impurity content must not exceed 300ppm. The slurry particle size distribution is uniform. Large particles of impurities must be strictly filtered and removed. There must be no excess bubbles in the slurry. The particle size must be uniform, easy to disperse, and the chemical properties must be stable.

[0004] For example, the "method for preparing high-purity alumina" disclosed in Chinese patent documents, with application number "CN201410626394.1", specifically involves loading the treated high-purity aluminum ingot into a melting furnace, first evacuating the furnace and continuously filling it with high-purity nitrogen, then heating the aluminum ingot to melt it, and the aluminum liquid is passed through a graphite liquid guide tube through high-pressure inert gas + high-purity water + high-speed rotating turntable to obtain active aluminum powder, which is hydrolyzed to generate aluminum hydroxide slurry, and then centrifugally dehydrated, dried, and crushed, and calcined in a high-temperature calcining furnace to obtain stable alumina powder, and then a briquetting machine is used to press the powder into shape and sinter it to a density greater than 3.7g / cm3.

[0005] Although the above scheme can obtain stable alumina powder through centrifugal dehydration and other methods, most domestic ceramic production currently adopts the process of iron removal by screening, which can only remove impurities above 35um, and the high-frequency vibrating screen is prone to produce more foam mixed into the slurry during operation, which is very unfavorable for the subsequent granulation. Therefore, a new process technology is needed to solve this problem. Summary of the invention

[0006] In order to overcome the problem of low efficiency in removing impurities and easy retention of foam in the slurry during the current ceramic production process, the present invention provides a method for treating high-purity alumina slurry, which realizes efficient screening, impurity removal and filtration of high-purity alumina slurry. These technical means ensure the high purity and high insulation of the slurry during the production process, while reducing production costs and improving production stability, thereby obtaining high-quality products that are competitive in the field of semiconductor material production.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions: A method for treating high-purity alumina slurry comprises the following steps: a. transporting high-purity alumina slurry to a screening device through a pipeline; b. the screened slurry flows into a receiving trough; c. the slurry flows into an iron removal device from a discharge port at the lower end of the receiving trough; d. transporting the slurry to a filtering device through a diaphragm pump; e. the filtered slurry passes through a strong magnetic iron remover; f. the slurry is defoamed and then transported to a storage tank.

[0008] The above steps are used to ensure the high purity and quality of the slurry. First, the slurry is transported to the screening equipment through a pipeline. This step can initially remove larger impurity particles and lay the foundation for subsequent fine processing. The screened slurry flows into the receiving trough. The design of the receiving trough helps to stabilize the bubbles in the slurry and provide suitable conditions for the next step of iron removal. Then, the slurry flows into the first iron removal equipment from the lower end outlet of the receiving trough. This step removes magnetic impurities in the slurry by physical means to ensure the purity of subsequent processes. The diaphragm pump transports the slurry that has undergone preliminary iron removal to the filtering equipment to further remove finer particles. The filtered slurry passes through the second iron removal equipment, namely the strong magnetic iron remover, to completely remove the remaining ferromagnetic impurities. Finally, the purified slurry is transported to the storage tank to complete the entire treatment process.

[0009] Each step in the process uses corresponding technical means to deal with specific impurity types and sizes. For example, screening equipment is used to remove large particles of impurities, while strong magnetic iron removers are used to remove tiny magnetic particles that may affect the performance of semiconductors. It can significantly improve the purity of alumina slurry and reduce the impurity content in the production process, thereby improving the quality and reliability of the final product. Compared with common treatment solutions, the advantage of this process is that it combines a variety of impurity removal technologies to ensure the thorough removal of impurities through step-by-step treatment, especially the use of strong magnetic iron removers in the removal of magnetic impurities, which significantly improves the impurity removal efficiency. In addition, the stability and controllability of the process are further improved by stabilizing bubbles in the receiving trough and using flexible pipes and flow control valves between each processing step.

[0010] The present application also discloses a processing device used in the above-mentioned high-purity alumina slurry processing method, including: a screening device, the screening device performs preliminary screening of the slurry; a receiving trough, the receiving trough receives the screened slurry; a first iron removal device, the first iron removal device is connected to the discharge port of the receiving trough; a diaphragm pump, the diaphragm pump is connected to the first iron removal device for slurry transportation; a filtering device, the filtering device is connected to the diaphragm pump; a second iron removal device, the second iron removal device is connected to the filtering device.

[0011] The screening equipment is responsible for the initial screening of the slurry, usually using a high-frequency vibrating screen to increase the screening efficiency and accuracy. The receiving trough follows the screening equipment and is used to receive the screened slurry and perform bubble stabilization treatment to ensure that the slurry has uniform properties before entering the next processing stage. The first iron removal equipment is connected to the receiving trough and is responsible for removing magnetic impurities in the slurry, which is crucial to prevent magnetic contamination that may occur in subsequent processes. As a key component of slurry transportation, the diaphragm pump uses a non-metallic diaphragm to avoid secondary contamination of the slurry, while ensuring the stability and reliability of transportation. The filtering equipment further removes fine particles that may exist in the slurry, using a rigid structure support to improve filtering efficiency and durability. The second iron removal equipment, the strong magnetic iron remover, uses a magnetic rod with high magnetic induction intensity to completely remove the remaining ferromagnetic impurities to ensure the high purity of the slurry.

[0012] The integrated design of this device combines multiple processing steps organically, improving processing efficiency and reducing operational complexity. Compared with common single processing equipment, the advantage of this integrated device is that it can achieve a continuous and automated processing process, reducing human intervention and potential contamination risks, while also improving production efficiency.

[0013] Preferably, the screening equipment includes a high-frequency vibrating screen, which is connected to the receiving trough by a flexible pipe. Due to its efficient screening ability, the high-frequency vibrating screen can effectively remove larger non-target particles in the slurry, ensuring the purity of the subsequent process stages. The flexible pipe provides a buffer mechanism that can absorb the vibration that may be generated during the screening process, thereby reducing the impact on the entire processing system and ensuring the stability of the system. In addition, the connection method of the flexible pipe allows a certain degree of displacement and deformation, which is particularly important in industrial applications because it can adapt to small movements and thermal expansion during equipment operation, reducing the risk of connection failure or leakage caused by pipe stress. The use of flexible pipes also facilitates the installation and maintenance of the equipment. It can simplify the installation process, reduce the precise alignment and fixation required for rigid pipes, and also facilitate future disassembly and replacement, reducing maintenance costs.

[0014] Preferably, it also includes a storage tank, which is connected to the discharge port of the magnetic iron remover.

[0015] Preferably, the storage tank is connected to a defoaming device.

[0016] As the final link of the entire processing flow, the storage tank is responsible for receiving the high-purity alumina slurry after being treated by the strong magnetic iron remover. The storage tank not only provides a safe and stable storage environment for the slurry, but also assumes the function of defoaming through its design, which is crucial to maintaining the consistency of the slurry and improving product quality.

[0017] Specifically, the design of the storage tank needs to consider a variety of factors, such as the corrosion resistance of the material, the smoothness of the interior to reduce wall hanging, and a large enough capacity to meet production needs. Its connection to the discharge port of the strong magnetic iron remover means that after the final iron removal step, the slurry flows directly into the storage tank, reducing the contamination or re-mixing of impurities that may occur during the transfer process.

[0018] In addition, the defoaming device equipped in the storage tank may be designed by physical or chemical methods to reduce or eliminate bubbles in the slurry, which is very important for the subsequent processing and quality control of the final product. For example, in the semiconductor industry, bubbles may cause product defects and affect the performance and reliability of the device. This solution ensures that the high-purity alumina slurry treated by the strong magnetic iron remover can be safely stored in an ideal state, while reducing potential problems caused by bubbles or other impurities. This not only improves production efficiency, but also ensures product quality.

[0019] The defoaming device exists to ensure that the slurry in the storage tank reaches the best state during storage. After continuous screening, iron removal and filtration steps, high-purity alumina slurry may still contain tiny bubbles. If these bubbles are not removed in time, they may affect the uniformity of the slurry and thus affect the quality of semiconductor products. The introduction of the defoaming device can effectively reduce or eliminate these bubbles through physical or chemical methods to ensure the stability and consistency of the slurry. Even the smallest defects in high-purity materials in the semiconductor manufacturing process may have a significant impact on the performance of the final product. The application of the defoaming device is to meet the strict requirements for quality control of high-purity alumina slurry during the production process.

[0020] Compared with common storage tanks, the advantage of this solution is that it not only provides a storage medium, but also integrates a defoaming function, which helps to improve production efficiency and reduce subsequent processing steps. In addition, the integrated design of the defoaming device reduces additional operations in the production process and reduces manual intervention, thereby reducing potential contamination risks. Directly connecting the defoaming device to the storage tank enables instant defoaming during storage, which is crucial to ensuring the quality of the slurry.

[0021] Preferably, the defoaming device includes a gas backflush section arranged on the high-frequency vibrating screen, and the gas backflush section includes horizontal radial pores evenly distributed on the surface of the slurry. By arranging a gas backflush port below the screen of the screening equipment, the foam generated during screening is blown away or crushed by controlling the flow rate and pressure of the gas. Gas backflush can effectively destroy the stability of the foam and reduce the generation of foam during the screening process, which is particularly important for materials such as high-purity alumina slurry that are sensitive to foam. The gas backflush section can process the foam immediately, reduce the impact of the foam on the screening efficiency and product quality, and also avoid the accumulation of foam inside the screening equipment, reducing maintenance costs. Compared with the common scheme, this scheme reduces the dependence on chemical defoamers and reduces the potential impact on the environment and product purity through the direct action of gas. The design of horizontal radial pores evenly distributed on the surface of the slurry can ensure that the gas backflush covers the entire screen surface, achieving a more uniform and comprehensive foam treatment effect. In addition, by accurately controlling the flow rate and pressure of the gas, the backflush intensity can be adjusted according to the characteristics of different slurries to achieve customized foam control.

[0022] Preferably, the defoaming device includes an electrostatic field generating unit arranged on the high-frequency vibrating screen, and the electrostatic field generating unit covers the entire area. By generating an electrostatic field in the screening area, an electrostatic force can be applied to the foam. Since the foam itself has a low electrical conductivity, this force will be concentrated on the surface of the foam, so that it will break quickly under the action of the electric field. The electrostatic field can provide a non-contact defoaming method, avoiding the damage that mechanical intervention may cause to the screening equipment or the slurry quality. In addition, the electrostatic field can effectively treat the tiny bubbles in the high-purity alumina slurry, which is difficult to achieve with traditional mechanical methods. The electrostatic field generating unit can achieve a fast and uniform defoaming effect, avoiding the accumulation of foam during the screening process and the decline in the quality of the slurry. At the same time, this method has low maintenance and cleaning requirements for the screening equipment, reducing downtime in the production process. Similar to the setting of the gas backflush unit, the generation of the electrostatic field does not rely on any chemical defoaming agent, thereby avoiding the risk of possible contamination of the product. And this design allows the intensity and distribution of the electrostatic field to be precisely controlled, and the electric field parameters can be adjusted according to different process requirements.

[0023] The defoaming device includes a foam separation tank, which is arranged in front of the storage tank. A liquid inlet and a liquid outlet are respectively arranged at both ends of the foam separation tank, and a foam collecting tank is arranged at the liquid outlet. A first electrode part and a second electrode part with opposite polarities are respectively arranged near the liquid inlet and the liquid outlet, and the first electrode part includes a polarity pin distributed along the surface of the foam separation tank; the second electrode part includes a polarity baffle with a through hole. A flow valve is arranged at the liquid inlet of the foam separation tank, and the slurry liquid level in the foam separation tank is not higher than the end of the polarity pin. A water pump for driving the slurry and the foam body above the slurry liquid level to flow is arranged at the bottom of the foam separation tank. The foam collecting tank includes a liquid analysis tube connected to the storage tank.

[0024] The foam separation tank is arranged in front of the storage tank to remove the foam in the slurry before it enters the storage tank. The arrangement of the liquid inlet and the liquid outlet allows the slurry and the foam to be separated, wherein the foam collection tank at the liquid outlet is used to collect and process the separated foam. This design can reduce the impact of the foam on the subsequent process and improve the quality of the alumina slurry. The first electrode part adopts polar pins distributed along the surface of the foam separation tank, while the second electrode part adopts a polar baffle with through holes. Through this electrode arrangement, an electric field can be created to promote the rupture and separation of the foam by electrostatic action. This electric field-assisted defoaming method can significantly improve the defoaming efficiency and reduce the defoaming time, thereby improving the efficiency of the entire treatment process. The flow valve controls the flow of the liquid inlet to ensure that the slurry liquid level in the foam separation tank is not higher than the end of the polar pin, which helps to prevent the foam from re-entering the slurry while maintaining the effective effect of the electric field on the foam. The water pump is arranged to drive the slurry and the foam body above the slurry liquid level to flow, further promoting the separation and collection of the foam. This dynamic control mechanism improves the adaptability and reliability of the defoaming device. Physical separation uses the density difference between foam and slurry to achieve separation through the structural design of the foam separation tank; electric field assistance uses the polarization and charge distribution of foam in the electric field to promote the rupture of foam and accelerate the defoaming process. Improve the purity and quality of alumina slurry and reduce the interference of foam on subsequent processes. In the production process of alumina slurry, the presence of foam may affect the fluidity, uniformity and stability of the slurry, thereby affecting the quality and performance of the final product. Through an effective defoaming device, the quality of the slurry and the stability of the production process can be ensured.

[0025] The design of the foam separation tank in this scheme realizes the effective separation of slurry and foam; secondly, the electrode part with opposite polarity introduces electric field-assisted defoaming, which improves the defoaming efficiency; finally, the setting of the flow valve and the water pump realizes the precise control of the flow of slurry and foam, and improves the adaptability and reliability of the defoaming device. The foam collection tank includes a liquid analysis tube connected to the storage tank. The main working principle of the liquid analysis tube is to use gravity to convert the broken foam into slurry liquid and guide it into the storage tank. In this process, the broken foam will be further separated in the liquid analysis tube, where the liquid part flows back to the storage tank through the liquid analysis tube, and the remaining foam or solid impurities are collected or further processed. Since the foam may contain air or other impurities, if it flows back to the storage tank directly, it may affect the quality of the slurry and the stability of the subsequent process. By setting up a liquid analysis tube, the foam and slurry liquid can be effectively separated to ensure the purity and stability of the slurry in the storage tank.

[0026] Preferably, the defoaming device includes a wave body auxiliary device arranged on the high-frequency vibrating screen, and the wave body auxiliary device includes an electromagnetic wave generator or an ultrasonic generator. Electromagnetic waves or ultrasonic waves are used as energy sources to physically defoam the foam. Among them, the electromagnetic wave or ultrasonic wave generator emits a specific wave body to the screening area. Electromagnetic waves can generate enough energy on the foam surface, causing the vibration of gas molecules inside the foam to intensify, and finally causing the foam to burst. Ultrasonic waves form tiny cavitation effects on the foam surface through their high-frequency vibrations. The energy released by these cavitation bubbles when they collapse is enough to destroy the structure of the surrounding foam. The wave body auxiliary device provides a defoaming method without adding chemicals and physical contact. This method can not only reduce pollution to the environment, but also avoid unnecessary chemical or physical damage to the alumina slurry. The wave body auxiliary device can effectively reduce the foam generated during the screening process, improve the screening efficiency, and avoid the influence of foam on subsequent process flows. Compared with chemical defoamers, this method protects product quality more thoroughly.

[0027] Preferably, the diaphragm pump includes a non-metallic diaphragm. The diaphragm pump plays a key role in slurry transportation in the processing device, and its design and material selection directly affect the operating efficiency of the entire equipment and the purity of the slurry. In traditional diaphragm pumps, the metal diaphragm may wear out due to long-term use, causing tiny metal particles to mix into the slurry, thereby affecting the purity of the high-purity alumina slurry. The application of non-metallic diaphragms effectively avoids this problem, reduces the risk of metal contamination, and ensures the high quality of the slurry.

[0028] Preferably, the filtration device includes a rigid structural support. The filtration device is responsible for removing tiny particles and impurities in the slurry to meet the strict requirements of the semiconductor industry for material purity. The introduction of the rigid structural support provides additional strength and stability to the filter, which is particularly important for withstanding the mechanical stress and pressure changes that may occur during continuous filtration operations. Specifically, the rigid structural support can effectively prevent the filter from being deformed or damaged during operation, thereby ensuring the consistency and reliability of the filtration effect.

[0029] Preferably, the first iron removal device is a grid-type iron remover, and the second iron removal device is a strong magnetic iron remover; the strong magnetic iron remover is provided with a strong magnetic rod with a magnetic induction intensity greater than 20000GS. As the first iron removal device, the grid-type iron remover is designed to allow the slurry to pass through a series of grid-like channels when entering, and the size and shape of these channels are carefully designed to maximize the capture efficiency of magnetic impurities. The use of the grid-type iron remover plays an important role in the preliminary removal of larger magnetic particles in the slurry, thereby laying a good foundation for the subsequent fine filtration and iron removal steps.

[0030] The second iron removal device, the strong magnetic iron remover, further ensures the high purity of the slurry. The magnetic rods set in the strong magnetic iron remover have a magnetic induction strength of more than 20,000GS, which can effectively absorb and remove finer magnetic impurities that may have an adverse effect on the performance of semiconductor devices. The high magnetic field strength of the strong magnetic iron remover is one of its main technical advantages, which ensures that even the smallest magnetic particles can be effectively removed.

[0031] The semiconductor industry has very strict restrictions on the magnetic impurity content of high-purity alumina slurries. By using two different strengths of iron removal equipment in stages, the magnetic impurities in the slurry can be removed more comprehensively to meet the industry's demand for high-purity materials. Compared with the common single iron removal equipment, the advantage of this solution is its two-stage iron removal configuration, which can more thoroughly remove magnetic impurities in the slurry. The combination of preliminary screening with a grid-type iron remover and fine removal with a strong magnetic iron remover provides a more comprehensive and effective iron removal solution.

[0032] Preferably, a flow control valve is installed on the pipeline between the grid-type iron remover and the diaphragm pump. The slurry delivery process is accurately controlled by a plurality of valves arranged on the delivery pipeline. The use of these valves is essential for achieving high automation and precise control of the device. Specifically, these valves arranged on the delivery pipeline include but are not limited to valves for adjusting the delivery speed, valves for switching the slurry between different processing units, and valves for sequential delivery of the slurry.

[0033] Preferably, the receiving trough is connected to the filter device through a pipeline, the filter device is connected to the second iron removal device through a pipeline, the second iron removal device is connected to the storage tank through a pipeline, and each pipeline connection includes a reducer elbow. The use of a reducer elbow can effectively reduce the turbulence and pressure loss that the slurry may encounter during transportation, while reducing the generation and mixing of bubbles, ensuring the stability and uniformity of the slurry during transportation. Specifically, in the production of high-purity alumina slurry, bubbles are one of the important factors affecting product quality. Bubbles may not only cause uneven density of the slurry, but also cause defects in subsequent processing. Therefore, reducing the generation and mixing of bubbles is crucial to ensuring product quality. The design of a reducer elbow can effectively disperse the flow rate of the slurry by changing the diameter and bending angle of the pipeline, reduce the shear force of the slurry during transportation, and thus reduce the generation of bubbles. In addition, the design of the reducer elbow also helps to guide the slurry to flow smoothly in the pipeline, reducing bubbles caused by local pressure concentration.

[0034] This solution has the following beneficial effects: Use high-frequency vibrating screen for screening to effectively reduce impurities below 35 microns and improve the purity of high-purity alumina slurry.

[0035] The diaphragm pump with non-metallic diaphragm avoids wear and contamination caused by long-term use and ensures the high purity characteristics of the slurry.

[0036] The high-efficiency filter removes fine particles larger than 1 micron and gel-like pollutants, further improving the uniformity and dispersion stability of the slurry.

[0037] The high magnetic induction intensity (greater than 20000GS) of the strong magnetic iron remover can completely remove ferromagnetic impurities and ensure the high insulation of high-purity alumina slurry.

[0038] The design of the reducer elbow reduces the generation of bubbles at the pipe connection, maintains the fluidity and stability of the slurry, and ensures the smooth progress of subsequent processes. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 The invention is a process flow chart.

[0040] Figure 2 Schematic diagram of the structure of the defoaming device in Example 2.

[0041] In the figure: 100 slurry liquid surface, 101 slurry foam, 1 screening equipment, 2 receiving trough, 3 filtering equipment, 4 first iron removal equipment, 5 diaphragm pump, 6 flow control valve, 7 second iron removal equipment, 8 storage tank, 9 defoaming device, 91 foam separation tank, 92 liquid inlet, 93 liquid outlet, 94 foam collecting tank, 95 separation slope, 10 first electrode part, 11 second electrode part, 12 polarity pin, 13 polarity baffle, 131 through hole, 14 water pump, 15 liquid analysis tube. DETAILED DESCRIPTION

[0042] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions.

[0043] Example 1 like Figure 1 As shown, in this embodiment, a method for processing high-purity alumina slurry is proposed, comprising the following steps: a. high-purity alumina slurry is transported to a screening device 1 through a pipeline; b. the screened slurry flows into a receiving trough 2; c. the slurry flows into a first iron removal device from a discharge port at the lower end of the receiving trough 2; d. it is transported to a filtering device 3 through a diaphragm pump 5; e. the filtered slurry passes through a second iron removal device; f. the slurry is finally transported to a storage tank 8.

[0044] The above steps are used to ensure the high purity and quality of the slurry. First, the slurry is transported to the screening equipment 1 through a pipeline. This step can preliminarily remove larger impurity particles and lay the foundation for subsequent fine processing. The screened slurry flows into the receiving trough 2. The design of the receiving trough 2 helps to stabilize the bubbles in the slurry and provide suitable conditions for the next step of iron removal. Then, the slurry flows into the first iron removal equipment 4 from the lower end outlet of the receiving trough 2. This step removes magnetic impurities in the slurry by physical means to ensure the purity of subsequent processes. The diaphragm pump 5 transports the slurry that has undergone preliminary iron removal to the filtering equipment 3 to further remove finer particles. The filtered slurry passes through the second iron removal equipment 7, i.e., a strong magnetic iron remover, to thoroughly remove the remaining ferromagnetic impurities. Finally, the purified slurry is transported to the storage tank 8 to complete the entire treatment process.

[0045] Each step in the process is targeted at specific impurity types and sizes, and corresponding technical means are used for processing. For example, the screening equipment 1 is used to remove large particles of impurities, while the strong magnetic iron remover is used to remove tiny magnetic particles that may affect the performance of semiconductors. It can significantly improve the purity of alumina slurry and reduce the impurity content in the production process, thereby improving the quality and reliability of the final product. Compared with common treatment schemes, the advantage of this process is that it comprehensively uses a variety of impurity removal technologies, and ensures the thorough removal of impurities through step-by-step treatment, especially the use of a strong magnetic iron remover in the removal of magnetic impurities, which significantly improves the impurity removal efficiency. In addition, the stability and controllability of the process are further improved by stabilizing bubbles in the receiving trough 2 and using flexible pipes and flow control valves 6 between each processing step.

[0046] The present application also discloses a processing device used in the above-mentioned high-purity alumina slurry processing method, including: a screening device 1, the screening device 1 performs preliminary screening of the slurry; a receiving trough 2, the receiving trough 2 receives the screened slurry; a first iron removal device 4, the first iron removal device 4 is connected to the discharge port of the receiving trough 2; a diaphragm pump 5, the diaphragm pump 5 is connected to the first iron removal device 4 for slurry transportation; a filtering device 3, the filtering device 3 is connected to the diaphragm pump 5; a second iron removal device 7, the second iron removal device 7 is connected to the filtering device 3.

[0047] The screening device 1 includes a high-frequency vibrating screen, which is connected to the receiving trough 2 through a flexible pipe. The storage tank 8 is connected to the discharge port of the magnetic iron remover, and the storage tank 8 is connected to a defoaming device. In addition, the diaphragm pump 5 includes a non-metallic diaphragm, and the filtering device 3 includes a rigid structure support.

[0048] The first iron removal device 4 is a grid-type iron remover, and the second iron removal device 7 is a strong magnetic iron remover; the strong magnetic iron remover is provided with a strong magnetic rod with a magnetic induction intensity greater than 20000GS. A flow control valve 6 is installed on the pipeline between the grid-type iron remover and the diaphragm pump 5.

[0049] The screening device 1 is responsible for the preliminary screening of the slurry, usually using a high-frequency vibrating screen to increase the screening efficiency and accuracy. The receiving trough 2 follows the screening device 1 and is used to receive the screened slurry and perform bubble stabilization treatment to ensure that the slurry has uniform properties before entering the next processing stage. The first iron removal device 4 is connected to the receiving trough 2 and is responsible for removing magnetic impurities in the slurry, which is crucial to prevent magnetic contamination that may occur in subsequent processes. The diaphragm pump 5, as a key component for slurry transportation, uses a non-metallic diaphragm to avoid secondary contamination of the slurry, while ensuring the stability and reliability of transportation. The filtering device 3 further removes fine particles that may exist in the slurry, and uses a rigid structure support to improve the filtering efficiency and durability. The second iron removal device 7, that is, a strong magnetic iron remover, uses a magnetic rod with high magnetic induction intensity to thoroughly remove the remaining ferromagnetic impurities to ensure the high purity of the slurry.

[0050] The integrated design of this device combines multiple processing steps organically, improving processing efficiency and reducing operational complexity. Compared with common single processing equipment, the advantage of this integrated device is that it can achieve a continuous and automated processing process, reducing human intervention and potential contamination risks, while also improving production efficiency.

[0051] In the semiconductor industry, high-purity alumina slurry is a key basic material, and the quality of its production process directly affects the quality and performance of the final product. In the face of the problems of incomplete impurity removal and easy mixing of bubbles in traditional processes, the high-purity alumina slurry processing process and device proposed in the present invention realizes efficient and high-quality processing of high-purity alumina slurry.

[0052] This embodiment provides an integrated and automated high-purity alumina slurry processing system, the basic structure of which includes multiple key components such as screening equipment 1, receiving trough 2, iron removal equipment, diaphragm pump 5, filtering equipment 3, strong magnetic iron remover and storage tank 8. These components are connected by well-designed pipelines to form an efficient and coordinated process flow.

[0053] First, the high-purity alumina slurry is transported to the screening device 1 through a pipeline. The screening device 1 uses a high-frequency vibrating screen equipped with a 500-mesh nylon screen, which can perform preliminary screening on the slurry and effectively remove larger particle impurities. The screened slurry flows into the receiving trough 2, which has sufficient volume to stabilize the slurry and provide necessary buffering for the subsequent iron removal and filtration steps.

[0054] The design of the receiving trough 2 is also crucial. A grid-type iron remover is installed at the lower end of the discharge port, which serves as the first iron removal device 4 to further remove possible residual magnetic impurities. This step is crucial to ensure the high purity of the high-purity alumina slurry. Subsequently, the slurry is transported to the filtering device 3 through a diaphragm pump 5. The diaphragm pump 5 uses a non-metallic diaphragm to avoid wear and contamination problems during long-term use, ensuring the purity of the slurry. The internal design of the filtering device 3 is supported by a rigid structure, which is not easily deformed and can effectively filter out fine particles with a diameter of more than 1 micron and deformable gel-like pollutants, further purifying the slurry. The filtered slurry enters a strong magnetic iron remover, which serves as the second iron removal device 7. A strong magnetic rod with a magnetic induction intensity greater than 20000GS is provided inside it, which can completely remove ferromagnetic impurities in the slurry. This step is crucial to ensure the high insulation of the high-purity alumina slurry, because the presence of ferromagnetic impurities will seriously affect the performance of semiconductor devices. Finally, the deironing and filtered slurry is transported to the storage tank 8, where it is subjected to static defoaming to eliminate bubbles that may be mixed in during the production process, thereby ensuring the uniformity and stability of the slurry.

[0055] The receiving trough 2 is connected to the filtering device 3 through a pipeline, the filtering device 3 is connected to the second iron removal device 7 through a pipeline, the second iron removal device 7 is connected to the storage tank 8 through a pipeline, and each pipeline connection includes a reducing elbow. In the entire processing system, the connection design of the pipeline is relatively important. Variable elbows are used at the pipeline connections between the receiving trough 2 and the filtering device 3, the filtering device 3 and the second iron removal device 7, and the second iron removal device 7 and the storage tank 8. This design not only reduces the shear force of the slurry during transportation and reduces the generation of bubbles, but also effectively disperses the flow rate of the slurry by changing the diameter and bending angle of the pipeline, reduces pressure loss, and improves transportation efficiency.

[0056] In addition, in this embodiment, the problem of flow control is also specially considered in the process flow. A flow control valve 6 is installed on the pipeline between the grid-type iron remover and the diaphragm pump 5. By accurately controlling the flow of the slurry, the coordination of each processing step can be ensured, further improving the processing efficiency and stability of the entire system.

[0057] Through the above-mentioned structural design and process flow, the high-purity alumina slurry processing process and device provided by the present invention can not only effectively remove impurities and bubbles in the slurry, ensuring the high purity and high insulation of the high-purity alumina slurry, but also improve production efficiency and reduce production costs through automated and integrated design.

[0058] In this embodiment, the high-frequency vibrating screen is a 500-mesh nylon screen with a processing capacity of 2t / h. The aperture and vibration frequency of the screen are precisely calculated to ensure that particles larger than a certain size are effectively removed without damaging the high-purity alumina slurry. In addition, the vibration mode during the screening process is specially designed to minimize the generation of foam, which is crucial to maintaining the stability of the slurry and the smooth progress of subsequent processes.

[0059] In the stabilization design of the receiving trough 2, the present solution adopts a large-capacity receiving trough 2, which can not only accommodate the screened slurry, but also balance the flow of the slurry to a certain extent and reduce the bubbles that may be generated due to the rapid flow. In addition, the smooth surface and special coating inside the receiving trough 2 further reduce the friction between the slurry and the trough wall, which helps to prevent the generation of additional impurities during the slurry flow.

[0060] Specifically, the design of the high-efficiency filter adopts a rigid structural support, which can resist particle unloading or filter bypass, ensuring the consistency and reliability of the filtering effect. In addition, the fine filter medium inside the filter can capture fine particles with a diameter of only 1 micron, which is crucial to improving the purity of the final product. The strong magnetic rods with high magnetic induction intensity of the strong magnetic iron remover can effectively adsorb and remove ferromagnetic impurities in the slurry. This step is crucial to meet the high insulation requirements of the semiconductor industry for high-purity alumina slurry. The high temperature resistance of the strong magnetic iron remover also ensures its stability and durability in industrial environments. The storage tank 8 not only provides a suitable environment for static defoaming of the slurry, but also further ensures the uniformity and stability of the slurry through the connected defoaming device. The capacity and shape design of the storage tank 8 allow the slurry to fully flow and mix in it, which helps to eliminate bubbles.

[0061] Example 2 This embodiment discloses the process of the high-purity alumina slurry treatment method in Example 1 as follows: High-purity alumina slurry is first transported to a high-frequency vibrating screen through a pipeline. At this stage, the vibration frequency and amplitude of the screen are precisely controlled to adapt to the characteristics of the slurry and optimize the screening effect. During the screening process, nylon screens with mesh sizes exceeding 500 can effectively intercept larger particle impurities while allowing pure slurry to pass smoothly. Issues that need to be paid attention to in this step include the cleaning and maintenance of the screen, as well as the balance and stability of the vibrating screen to avoid unnecessary equipment wear or production interruptions.

[0062] The screened slurry then flows into the receiving trough 2. The design of this receiving trough 2 must ensure sufficient volume to accommodate the screened slurry, while also facilitating the stabilization and uniform distribution of the slurry. In the receiving trough 2, the slurry will stay for a short time, which is crucial for stabilizing the characteristics of the slurry, especially eliminating bubbles that may be generated during the screening process. In addition, the design of the receiving trough 2 should take into account easy cleaning and maintenance to prevent any potential cross contamination.

[0063] Next, the slurry flows from the outlet at the lower end of the receiving trough 2 into the first iron removal device 4, i.e., a grid-type iron remover. This device is designed to further remove magnetic impurities that may remain in the slurry. The design of the iron remover must take into account its effect on the slurry flow rate and flow rate, as well as how to effectively capture and remove impurities. In this step, regular inspection and cleaning of the iron remover is necessary to maintain its efficient iron removal performance.

[0064] After being processed by the first iron removal equipment 4, the slurry is transported to the filtering equipment 3 through the diaphragm pump 5. The selection of the diaphragm pump 5 is crucial to the entire process. The use of non-metallic diaphragms not only avoids the contamination of the slurry caused by metal wear, but also ensures the low-noise operation and high efficiency of the pump. In this step, the operator needs to monitor the pressure and flow of the diaphragm pump 5 to ensure the smooth transportation of the slurry. The design of the filtering equipment 3 adopts a rigid structural support, which helps to maintain the stability of the equipment and prevent deformation during the filtration process. The accuracy of the filter medium must be high enough to intercept fine particles with a diameter of only 1 micron. In this step, the pressure and flow of the filtering equipment 3 also need to be closely monitored to ensure the maximization of the filtering effect.

[0065] The filtered slurry is then transported to the strong magnetic iron remover through a pipeline for a second iron removal process. The strong magnetic rod inside the strong magnetic iron remover can provide a magnetic induction intensity of more than 20,000GS to ensure the complete removal of ferromagnetic impurities. This step is crucial to meet the high insulation requirements of high-purity alumina slurry.

[0066] In the embodiments of this patent application, we propose an innovative high-purity alumina slurry treatment method and corresponding device, which aims to achieve efficient and high-purity treatment of alumina slurry through a series of precisely designed steps and equipment, with special attention paid to the generation and reduction of foam. The following is a detailed analysis of the overall principle and working principle of the scheme, as well as an explanation of the structure, connection method and advantages.

[0067] First, the entire process starts with the delivery of high-purity alumina slurry. The slurry enters the screening equipment through a pipeline and is initially screened using a high-frequency vibrating screen to remove larger solid particles. The screened slurry flows into the receiving trough, which is designed to receive the screened slurry and provide a stable source of materials for the subsequent iron removal and filtration steps. Next, the slurry flows into the first iron removal equipment from the outlet at the lower end of the receiving trough. The function of this iron removal equipment is to remove possible iron impurities in the slurry and ensure the purity of the alumina slurry. The diaphragm pump is connected to the first iron removal equipment and is responsible for transporting the slurry to the filtration equipment to further remove tiny impurities. The filtered slurry passes through the second iron removal equipment, which uses a strong magnetic iron remover and is equipped with a strong magnetic rod with a magnetic induction intensity greater than 20,000 GS to ensure that iron impurities are completely removed. This step is crucial for the production of high-purity alumina products.

[0068] like Figure 2 As shown, in this embodiment, a foam separation tank is used for defoaming. Before the slurry that has passed through the second iron removal equipment enters the storage tank, it will pass through a specially designed defoaming device. The defoaming device includes a foam separation tank 91, which is located in front of the storage tank, and is provided with a liquid inlet 92 and a liquid outlet 93 at both ends. The design of the foam separation tank 91 allows the foam to gather therein and gradually separate. A first electrode portion 10 and a second electrode portion 11 with opposite polarities are respectively provided near the liquid inlet and the liquid outlet 93. The first electrode portion 10 is composed of polarity pins 12 distributed along the surface of the foam separation tank 91, while the second electrode portion 11 is a polarity baffle 13 provided with a through hole 131. The purpose of this electrode configuration is to promote the breakage of foam through the action of an electric field. The foam produces a charge distribution in the electric field due to polarization, which makes it easier for the foam to break and release the gas therein.

[0069] A flow valve is provided at the liquid inlet 92 of the foam separation tank 91 to control the inflow speed of the slurry and ensure that the slurry liquid level is not higher than the end of the polarity pin 12, so as to maintain the effective effect of the electric field on the foam. At the same time, a water pump 14 is installed at the bottom of the foam separation tank 91 to drive the slurry and the foam body above the slurry liquid level to flow, further improving the defoaming efficiency. The design of the liquid analysis tube 15 is crucial. It connects the foam collection tank 94 and the storage tank to ensure that the slurry liquid after defoaming can be safely and efficiently returned to the storage tank. The liquid outlet 93 is connected to the storage tank to transport the foam-free slurry out of the foam separation tank 91. The design of the liquid analysis tube 15 allows the foam to be broken and converted into slurry liquid with the assistance of the electric field, and then flows into the storage tank by gravity, while collecting and processing the remaining foam or solid impurities.

[0070] Finally, the slurry after two iron removal and defoaming processes is transported to the storage tank 8. The design of the storage tank 8 should take into account the static defoaming requirements of the slurry and how to effectively remove the air in the slurry. In this step, the operator needs to monitor the pressure and temperature of the storage tank 8 to ensure the stability and quality of the slurry.

[0071] It is worth noting that during the installation of the defoaming device, the setting of the foam separation tank 91 is crucial. The liquid inlet 92 and the liquid outlet 93 of the foam separation tank 91 need to be precisely positioned to achieve effective separation of slurry and foam. The installation of the first electrode portion 10 and the second electrode portion 11 with opposite polarities needs to take into account their relative positions with the foam separation tank 91 to achieve the best electric field distribution and foam breaking effect. A separation slope 95 is provided between the slurry liquid surface and the slurry foam body near the second electrode portion 11, which can be used with the help of the driving force of the water pump 14 so that the slurry foam body leaves the liquid surface and approaches the second electrode portion 11 under the "splitting" effect of the separation slope 95 during the flow of the slurry. It is worth noting that the separation slope 95 is a porous structure, which can make the foam that does not reach the upper slope of the separation slope 95 and flows to the bottom of the separation slope 95 attracted by the second electrode portion 11 and can also enter the via 131 through the porous structure for further processing.

[0072] The installation of the water pump 14 at the bottom of the foam separation tank 91 needs to ensure that it can effectively drive the slurry and foam to flow, while avoiding damage to the foam separation tank 91. The installation position of the flow valve should be easy to adjust to control the inflow speed of the slurry. The installation of the liquid separation tube 15 connects the foam collection tank 94 and the storage tank, and it is necessary to ensure that the connection is well sealed to avoid leakage. The length and inclination angle of the liquid separation tube 15 need to be adjusted according to the position of the storage tank to ensure that the slurry liquid after defoaming can flow back to the storage tank smoothly.

[0073] In the operation process, first start the screening equipment and adjust the vibration frequency of the high-frequency vibrating screen so that the slurry can achieve the best screening effect during the screening process. Subsequently, the slurry flows into the receiving trough and the iron impurities are removed by the first iron removal equipment. The diaphragm pump is started to transport the slurry to the filtering equipment to further remove tiny impurities. The filtered slurry enters the second iron removal equipment and the remaining iron impurities are removed by a strong magnetic field. Subsequently, the slurry enters the foam separation tank 91 and the foam is broken by an electric field-assisted defoaming device. The flow valve adjusts the inflow speed of the slurry to ensure that the slurry liquid level is not higher than the end of the polarity pin 12. The water pump 14 is started to drive the slurry and foam body to flow and promote the separation of the foam.

[0074] The defoamed slurry flows back to the storage tank through the liquid analysis pipe 15. During the entire operation, it is necessary to monitor the operating status of each device to ensure the smooth progress of the screening, iron removal, filtration and defoaming steps. At the same time, it is necessary to regularly check the sealing performance of the equipment to avoid leakage or air ingress.

[0075] In the whole operation process, the design and connection of the pipeline are crucial to ensure the smooth transportation and processing of the slurry. In particular, the connection between the receiving tank 2 and the filter device 3, the filter device 3 and the strong magnetic iron remover, and the strong magnetic iron remover and the foam separation tank 9191 adopts the design of a variable diameter elbow, which helps to reduce the generation of bubbles and the resistance of the slurry flow.

[0076] In addition, each component of this embodiment has certain flexibility and replaceability. For example, the screening device 1 can select different types of screens according to the specific characteristics of the slurry; the design of the iron remover can be adjusted according to the production scale and demand; the filter medium of the filter device 3 can be replaced according to different filtering accuracy requirements; the model and specification of the diaphragm pump 5 can also be selected according to the viscosity and flow requirements of the slurry.

[0077] The process flow and equipment design of the present invention take into account the production characteristics of high-purity alumina slurry, and effectively improve the purity and quality of the product through multi-step purification and impurity removal. The introduction of automation and monitoring systems not only improves production efficiency, but also reduces the impact of human factors on product quality. Each component of the present invention has a certain degree of flexibility and replaceability, which facilitates production of different scales and needs. Finally, through reasonable equipment layout and pipeline design, the present invention also takes into account the maintenance and cleaning issues in the production process, ensuring the stability and reliability of production.

[0078] The innovation of the present invention is also reflected in its comprehensive consideration of the continuity of the process flow, the degree of automation and the adaptability to the environment. In the field of semiconductor material production, continuous and stable production is of great significance for ensuring product quality and reducing costs. The present invention achieves the continuity and stability of the production process through the introduction of a reasonable equipment layout and an automated control system, thereby improving production efficiency and product quality.

[0079] In addition, the present invention takes full account of environmental factors such as the influence of temperature, humidity, etc. on the production process during design. For example, in the design of the storage tank 8, the stability of the slurry during storage is ensured by controlling the pressure and temperature in the tank. At the same time, strict control of temperature throughout the process also helps to reduce product quality fluctuations caused by environmental changes.

[0080] In addition, the process flow and equipment design of the present invention also have certain scalability. With the expansion of production scale and the advancement of technology, the various components of the present invention can be upgraded and improved accordingly to meet higher-level production needs. For example, the screening efficiency can be improved by increasing the number of screening devices 1 or improving the degree of automation of the screening device 1; more advanced filtering technology can be introduced to further improve the filtering effect and reduce the operating cost.

[0081] Example 3 In this embodiment, different screening technologies, such as ultrasonic assisted screening, can be considered to further improve screening efficiency and reduce foam generation. The defoaming device includes a wave body auxiliary device arranged on a high-frequency vibrating screen, and the wave body auxiliary device includes an electromagnetic wave generator or an ultrasonic generator.

[0082] The foam is physically defoamed using electromagnetic waves or ultrasonic waves as energy sources. The electromagnetic wave or ultrasonic wave generator emits a specific wave body to the screening area. Electromagnetic waves can generate enough energy on the foam surface to intensify the vibration of gas molecules inside the foam, and eventually cause the foam to burst. Ultrasonic waves form tiny cavitation effects on the foam surface through their high-frequency vibrations. The energy released by these cavitation bubbles when they collapse is enough to destroy the structure of the surrounding foam. Wave-body-assisted equipment provides a defoaming method that does not require the addition of chemicals or physical contact. This method not only reduces pollution to the environment, but also avoids unnecessary chemical or physical damage to the alumina slurry. Wave-body-assisted equipment can effectively reduce the foam generated during the screening process, improve screening efficiency, and avoid the impact of foam on subsequent process flows. Compared with chemical defoamers, this method protects product quality more thoroughly.

[0083] Example 4 In this embodiment, the design of the entire defoaming device is based on the principle of fluid mechanics, and aims to destroy the foam structure by gas backflush, thereby achieving the purpose of defoaming. The gas backflush part is composed of a series of radial air holes evenly distributed below the screen, which can exert uniform force on the foam below to promote the rapid rupture of the foam.

[0084] The basic structure of the device includes a high-frequency vibrating screen, a gas supply system, and an air hole layout. The design of the high-frequency vibrating screen ensures the high efficiency of the screening process, while the gas supply system provides the required pressure and flow to achieve gas backblowing. The layout design of the air holes is crucial and needs to be optimized according to the size and shape of the screen surface and the characteristics of the foam to ensure the uniformity of the gas backblowing and the defoaming effect. First, the gas supply system needs to be connected to the screening equipment to ensure that the gas can be smoothly delivered to the air holes. During the screening process, the gas flow and pressure are adjusted according to the generation of foam to achieve effective control of the foam. Issues that need attention include the stability of the gas pressure, the cleaning and maintenance of the air holes, and the safety of the gas supply system. By reasonably designing the structure and parameters of the gas backblowing part, the technicians in this field can improve the screening efficiency and reduce the production cost while maintaining the quality of the high-purity alumina slurry.

[0085] Example 5 In this embodiment, an electrostatic field is created in the screening area to destroy the foam structure. The design concept of the entire device is to use electrostatic force to affect the charge distribution on the foam surface, causing the gas molecules in the foam to vibrate, and finally causing the foam to break. The effect of this electrostatic force is purely physical and does not involve any chemical additives. It is crucial to maintain the purity of high-purity alumina slurry.

[0086] The core components of this device include a high-frequency vibrating screen, an electrostatic field generator, and a matching power supply system. The electrostatic field generator generates the required voltage and electric field strength, and through proper configuration with the screen, forms a uniform electrostatic field covering the entire screening area. The power supply system is responsible for providing a stable power supply to ensure the continuous effect of the electrostatic field.

[0087] In terms of the operation process, first of all, the electrostatic field generator needs to be correctly connected to the screening equipment and the stable power supply of the power system needs to be ensured. During the screening process, the intensity of the electrostatic field is adjusted according to the generation and accumulation of foam to achieve the best defoaming effect. Issues that need attention include the installation position of the electrostatic field generator, the safety of the power system, and the uniformity of the electrostatic field during the screening process.

Claims

1. A method for treating high-purity alumina slurry, comprising the following steps: a. High-purity alumina slurry is transported to the screening equipment through pipelines; b. The screened slurry flows into the receiving trough; c. The slurry flows into the first iron removal device from the outlet at the lower end of the receiving trough; d. It is transported to the filtering device through a diaphragm pump; e. The filtered slurry passes through the second iron removal device; f. The slurry is defoamed and transported to the storage tank.

2. A processing device used in the high-purity alumina slurry processing method according to claim 1, comprising: Screening equipment: the screening equipment performs preliminary screening of the slurry; A receiving trough, which receives the slurry after screening; A first iron removal device, the first iron removal device is connected to the discharge port of the receiving trough; A diaphragm pump, the diaphragm pump is connected to the first iron removal equipment to transport the slurry; A filtering device, the filtering device is connected to a diaphragm pump; The second iron removal device is connected to the filtering device.

3. The processing device according to claim 2, characterized in that The screening equipment comprises a high-frequency vibration screen, and the high-frequency vibration screen is connected to a material receiving trough through a flexible pipeline.

4. The processing device according to claim 2, characterized in that It also includes a storage tank; a defoaming device is arranged between the storage tank and the discharge port of the second iron removal equipment.

5. The processing device according to claim 4, characterized in that The defoaming device comprises a foam separation tank, which is arranged in front of the storage tank. A liquid inlet and a liquid outlet are respectively arranged at both ends of the foam separation tank. The liquid inlet is connected to the second iron removal equipment, and the liquid outlet is connected to the storage tank.

6. The processing device according to claim 5, characterized in that A first electrode portion and a second electrode portion with opposite polarities are respectively arranged near the liquid inlet and the liquid outlet. The first electrode portion includes polarity pins distributed along the surface of the foam separation tank; the second electrode portion includes a polarity baffle with through holes, and a foam collection tank is arranged behind the polarity baffle.

7. The processing device according to claim 6, characterized in that The liquid inlet of the foam separation tank is provided with a flow valve, the slurry liquid level in the foam separation tank is not higher than the end of the polarity pin, and a water pump for driving the slurry and the foam body above the slurry liquid level to flow is provided at the bottom of the foam separation tank.

8. The processing device according to claim 4, characterized in that The foam collecting tank includes a liquid analysis tube connected to the material storage tank.

9. The processing device according to claim 5, characterized in that The defoaming device comprises a gas backflush portion arranged on the high-frequency vibration screen, and the gas backflush portion comprises horizontal radial air holes uniformly distributed on the surface of the slurry.

10. The processing device according to any one of claims 2 to 8, characterized in that: The first iron removal device is a grid-type iron remover, and the second iron removal device is a strong magnetic iron remover; the strong magnetic iron remover is provided with a strong magnetic rod with a magnetic induction intensity greater than 20000GS.

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