Analysis of the production process of silicon micro powder

Silicon micropowder is a silica powder material made from natural quartz ore, fused silica and other raw materials through multiple processes such as grinding, fine grading and impurity removal. It is widely used in copper clad laminate, epoxy plastic packaging materials for chip packaging, electrical insulation materials, adhesives, ceramics, coatings, fine casting, daily chemical industry and other fields. The production process of silicon micro powder. Currently, the production equipment for silicon micro powder mainly includes ball mills, vibration mills, air flow mills, micro powder classifiers, and dryers. There are two production processes: dry grinding and wet grinding. Dry grinding production process; Grind the silicon micro powder raw material in a ball mill or vibration mill. This grinding process can continuously feed and discharge, or can input several weights of raw materials at once and grind continuously for several times before discharging; When discharging, the particle size should be controlled by a micro powder classifier. Coarse products should be returned to the mill for further grinding or used as products, while fine products are considered as products. Dry grinding requires strict control over the moisture content of the material being ground, so that the product is no longer dry; Wet grinding production process involves adding a certain weight of silicon micro powder raw materials into a ball mill at once, adding an appropriate amount of water, and operating at a concentration of 65-80%; After continuous grinding for more than ten hours, pour out the slurry and use pressure filtration method or place it in a material bucket for natural precipitation and dehydration to obtain a water containing material cake; After being crushed and dispersed with a crusher, it is evenly and continuously fed into a hollow shaft mixing and drying machine to obtain the product after drying.

      Whether it is dry grinding or wet grinding, in order to avoid material contamination during grinding, non-metallic materials such as alumina ceramic balls or silica should be used as grinding media; The barrel of the grinder is also lined with high-strength wear-resistant materials such as alumina ceramics, silica or polyurethane rubber. The key points for quality control of silicon micro powder products include ultrafine grinding, which is one of the core processes in the production of silicon micro powder products and directly affects their purity, particle size distribution, and production costs. In the production process of silicon micro powder, the key points for product quality control are as follows: Mill control: By selecting grinding medium materials reasonably, controlling medium ratio and filling rate, effectively controlling impurity content, and improving equipment service life; According to the aspect ratio of the ball mill, the structure and distribution of the lining plate, and the particle size of the grinding material, adjust the ball mill speed reasonably to maintain a good motion state of the material in the grinding chamber, thereby improving the grinding effect. Particle shaping: By optimizing process conditions such as equipment operating speed, internal pressure and temperature, and material residence time, the surface regularity of silicon micro powder can be improved, the flowability of the product can be enhanced, and it is beneficial for high filling and dispersion of silicon micro powder in downstream resin systems. Mixing and compounding: Single peak distribution of silicon micro powder cannot achieve very tight packing, which is difficult to meet the high filling requirements of customers and cannot fully exert the excellent performance of silicon micro powder. One of the methods to improve the filling rate is to mix silicon micro powder products with different particle size distributions, forming a multimodal distribution through proportioning and mixing, achieving high filling while also reducing the oil absorption value of silicon micro powder. Surface modification: Silicon micro powder, as an inorganic filler, has poor compatibility and difficult dispersion when mixed with organic resins, resulting in reduced heat and moisture resistance of materials such as integrated circuit packaging and substrates, thereby affecting product reliability and stability. To improve the interface bonding between silicon micro powder and organic polymer materials and enhance their application performance, surface modification of silicon micro powder is generally required. Production condition control: The key to producing electronic grade silicon micro powder is to remove conductive impurities from quartz. Therefore, in addition to selecting relatively pure raw materials, every step of production should minimize the pollution of containers, environment, chemical agents, etc. to the product, and operate strictly.