The drawer strong magnetic separator JH-X08 is primarily used for the purification and preparation of ultrafine silicon micropowder. Thanks to its ultra-high magnetic field strength and scientific layout, it can more effectively screen ultrafine magnetic impurities, ensuring the quality of the ultrafine silicon micropowder. This machine is based on our company’s self-developed patented technology and features a strict sealing design. It has been simplified and lightened to reduce operational strain on workers. Additionally, in consideration of airborne impurities and potential iron impurities generated during production, a dedicated dust-proof panel has been designed to prevent contamination of the product during the cleaning process.
Applications of Ultrafine Silicon Micropowder
Ultrafine silicon micropowder is a finely processed, high-purity silicon material with an extremely small particle size. Its main uses are as follows:
High-Tech Ceramic Materials
Ultrafine silicon micropowder is an important raw material for high-tech ceramics used to manufacture high-performance structural and functional ceramics. Its high purity and small particle size result in ceramics with greater density, mechanical strength, and electrical properties.
Electronic Industry Applications
In the electronics industry, ultrafine silicon micropowder is used as a raw material for electronic ceramics and electronic pastes, playing a key role in improving the performance and stability of electronic products.
Fillers for Rubber and Plastics
Ultrafine silicon micropowder can be used as a high-quality filler for rubber and plastics, enhancing their wear resistance, anti-aging properties, and mechanical performance.
Additive for Coatings and Paints
Due to its excellent flowability and anti-caking properties, ultrafine silicon micropowder is an important additive in coatings and paints, enhancing the hardness, weather resistance, and corrosion resistance of the coatings.
Optical Glass Raw Material
Ultrafine silicon micropowder is also used as one of the raw materials for optical glass, where it helps regulate the refractive index and transparency of the glass by adding specific impurity elements.
Copper-Clad Laminates (CCL)
Additionally, silicon micropowder is used in copper-clad laminates (CCL). Its main role is to reduce the thermal expansion rate of the CCL, improve its heat resistance, damp heat resistance, reduce moisture absorption, increase substrate peel strength, and improve the rigidity and crack resistance of thin CCL substrates. Spherical silicon micropowder has a high packing density and uniform stress distribution, which improves its flowability in fillers and reduces the viscosity of fillers.
Therefore, it is rapidly being applied in industries such as large-scale and ultra-large-scale integrated circuit encapsulants and high-performance copper-clad laminates. The use of spherical silicon micropowder in high-end copper-clad laminates requires the particle size to be neither too large nor too small. Panasonic Electric proposed that silicon micropowder with an average particle size greater than 10μm would reduce the electrical insulation properties of the resulting copper-clad laminate, while an average particle size smaller than 0.05μm would significantly increase resin viscosity, affecting the manufacturing process. Kyocera Chemical proposed that the average particle size of molten silicon micropowder should be between 0.05-2μm, with the maximum particle size below 10μm, to ensure the flowability of the resin system. Hitachi Chemical suggested that, in terms of improving the heat resistance and bond strength of copper-clad laminates, the average particle size of synthetic silicon micropowder should range from 1-5μm, but for the copper-clad laminate drilling process, the optimal range would be 0.4-0.7μm.
Recent Developments in the Preparation of High-Quality Spherical Silica
In recent years, the demand in high-tech fields such as large-scale integrated circuits, aerospace, fine chemicals, and daily-use cosmetics has been growing, making the preparation of high-quality spherical silica a research focus.
The preparation methods for spherical silica are divided into physical and chemical methods based on whether a chemical change occurs. Physical methods include mechanical grinding, spray drying, flame spheroidization, plasma methods, high-temperature calcination, etc. Chemical methods mainly include vapor-phase, precipitation, hydrothermal, sol-gel, and microemulsion methods.
Mechanical Grinding Method
The mechanical grinding method uses specialized crushing equipment and auxiliary screening devices to produce ultrafine powders. It can be divided into dry and wet methods based on material conditions. The wet grinding method uses water as a carrier medium to stir and grind the particles, producing well-dispersed products with uniform particle size.
Spray Drying Method
Spray drying involves quickly drying liquid raw materials using a spray dryer. The liquid is atomized into fine droplets, which come into contact with hot air. The moisture moves outward, and the raw material particles agglomerate. After drying, the desired product is obtained.
Flame Spheroidization Method
At high temperatures (1600-2000°C), the sharp edges of the powder are gradually melted, and under surface tension, it forms spherical particles. Using ordinary quartz powder as raw material and applying an oxygen-acetylene flame, spherical silica micropowder is produced with a smooth surface and a spheroidization rate of up to 95%.
Flame Melting Method
Using angular silica micropowder as raw material, it undergoes pre-treatment such as crushing, screening, and purification. The angular silica micropowder is crushed using an airflow crusher and screened to the desired particle size. Acetylene, natural gas, and other gases are used as heat sources. The suitable-sized angular silica micropowder is rapidly melted by high-temperature flame and quickly cooled to form spherical particles, resulting in high-purity and uniformly sized spherical silica micropowder.
Plasma Method
The plasma method uses the high-temperature area generated by arc plasma to melt silica powder or quartz powder into droplets. Under surface tension, the droplets form spheres. After cooling, spherical silica particles are formed.
High-Temperature Calcination Spheroidization Method
The high-temperature calcination spheroidization method involves aging coarse quartz powder under alkaline conditions, followed by filtration. The filtered material is dehydrated, dried, and then bound to form block samples. These are calcined in a high-temperature furnace, cooled, and dispersed. After grinding, spheroidization, magnetic separation, and air classification, high-purity ultrafine spherical silica micropowder is produced. This method results in a high spheroidization rate, good whiteness, high purity, and good flowability and dispersibility. It is still at the experimental stage.
Direct Combustion Method (VMC)
Since flame-melted spherical silica is derived from natural mineral powders, it has certain limitations in purity and particle size distribution. A few leading foreign companies use the direct combustion method (VMC), where metallic silicon powder directly reacts with oxygen to prepare high-purity, small-sized, and relatively controllable spherical silica micropowder.
High-Temperature Melting and Spraying Method
In the high-temperature melting and spraying method, high-purity quartz is melted at 2100-2500°C and sprayed. After cooling, spherical silica micropowder is obtained. The product has a smooth surface, and both the spheroidization and amorphousness rates can reach 100%. Some manufacturers in the U.S. and Japan use this method to produce spherical silica micropowder, but they strictly guard the process. This method ensures a high spheroidization rate and amorphousness, but challenges include handling high-temperature materials, the atomization system for the viscous molten quartz, adjusting the atomization particle size, and preventing contamination and further purification.
Self-Propagating Low-Temperature Combustion Method
The self-propagating low-temperature combustion method involves several steps, including the preparation of sodium silicate, the preparation of silica sol, the preparation of mixed combustion liquid, the combustion reaction, annealing to remove carbon and washing. The method is advantageous because it uses natural crystalline silica micropowder or molten silica micropowder as raw materials, which are readily available. The process is simple, requires no special equipment, is easy to control, and is low-cost. The materials used are water-soluble sodium and nitrate ions, which do not introduce other impurity ions, facilitating the preparation of high-purity silica micropowder. This method is still in the experimental stage and has not yet reached large-scale production.
Vapor-Phase Method
The vapor-phase method involves the distillation of silicon halides in a distillation column. After high-temperature vaporization, the silicon halides react with hydrogen and oxygen in a pressurized environment to undergo hydrolysis at high temperatures. The product is collected by a cyclone collector to obtain vapor-phase nanoparticles. This method produces silica particles with high purity and a controllable reaction process. However, it is costly and the organic byproducts generated during the process are difficult to treat.
Precipitation Method
Using water glass, acidifying agents, and surfactants, spherical silica micropowder is prepared. The temperature must be carefully controlled during the preparation process. If the pH exceeds 8, stabilizers must be added. After washing, drying, and calcining, spherical silica micropowder is formed. The spherical silica micropowder produced by this method has very uniform particle size, low cost, and simple process, making it suitable for industrial applications. However, agglomeration may occur as a drawback.
Hydrothermal Synthesis Method
Hydrothermal synthesis is a common liquid-phase method for preparing nanoparticles, typically carried out under high temperatures (150°C-350°C) and high pressure. In this method, inorganic and organic compounds react with water, forming ion clusters in a seed crystal growth zone to produce supersaturated solutions and crystals. Filtering, washing, and drying these inorganic products results in ultrafine, high-purity particles. Using hydrothermal synthesis for spherical silica micropowder reduces the risk of hard agglomeration and eliminates the need for conversion to oxides.
Sol-Gel Method
The sol-gel method involves uniformly mixing the raw materials with a liquid phase, followed by hydrolysis under specific conditions. Chemical condensation forms a sol, which after a period of time, forms a three-dimensional network structure, resulting in silica gel. After filtration, washing, drying, and sintering, nanosilica or quartz particles are obtained.
Microemulsion Method
A microemulsion is a uniform emulsion formed under the action of a surfactant between two immiscible phases. This method uses the tiny space at the interface of the two phases, directing nucleation and growth of particles under silica source guidance. After heat treatment, spherical silica or quartz particles are obtained. The limited space for nucleation and growth results in smaller and less likely to aggregate silica particles.
Features of the Drawer Strong Magnetic Separator JH-X08
The drawer strong magnetic separator JH-X08 produced by our company has the following features:
1. High-Quality Material Construction
The box body and drawer panel are made of high-quality stainless steel (nylon or PP materials can also be provided according to customer requirements). The box body and drawer panel are reliably sealed to prevent internal material leakage and environmental contamination effectively. It also effectively prevents external contaminants from entering, ensuring product quality.
2. Enhanced Iron Removal Efficiency
Each layer inside the box is equipped with diversion wedges to block material bypassing the gap between the box wall and the magnetic rods, thereby improving the iron removal effect. The installation and cleaning processes are simple and convenient. The device does not consume energy, ensuring low operating costs.
3. Adaptability to Material Features
This equipment can be adapted to different material characteristics, offering three types of magnetic rods:
- JH-B Standard Cylindrical Magnetic Rod
- JH-L Spiral Magnetic Field Cylindrical Magnetic Rod
- JH-Z Linear Magnetic Field Cylindrical Magnetic Rod
The maximum magnetic field can reach 16000GS. Each type has a unique, optimized magnetic circuit design that forms a high-gradient magnetic field, ensuring the best cost-performance ratio and iron removal efficiency. It is mainly used for the purification of ultrafine silicon micropowder, effectively removing iron impurities larger than 80 mesh and most magnetic impurities smaller than 80 mesh.
4. PTFE Coating Option
The interior of the box can be coated with PTFE according to customer requirements, effectively preventing machine iron powder from contaminating the product during use.
5. Improved Model with Rails and Dust-proof Panel
This improved model is equipped with rails and a dust-proof panel, which helps reduce the operational burden on workers and effectively prevents iron powder from entering the machine during the cleaning process. (Note: To reduce the impact of iron powder during the blowing process, a dedicated blowing chamber can be considered.)
6. Custom Design Available
Non-standard designs can be provided to meet different customer requirements.
For more information about the drawer strong magnetic separator JH-X08, you can watch the product video.
Conclusion
Additionally, we have designed and developed self-cleaning magnetic separator with a magnetic strength of 12000-13000GS. It can thoroughly remove magnetic impurities with sizes ≥80 mesh and has been widely applied in the purification and preparation of silicon micropowder. The fully automated design effectively reduces the workload for workers, and the high-intensity magnetic field can remove even finer impurities. The machine is made from high-strength, thick stainless steel plates processed by CNC, ensuring high durability and long-lasting performance. The fully sealed design effectively prevents external contaminants from affecting the purity of the product.