Why do we need ultrafine grinding？
Ultrafine grinding is a high and new technology that has developed rapidly in the past 20 years. It is one of the most important technologies for fine powder processing. With the development of modern high-tech and new material industries, ultrafine grinding technology can process raw materials into micrometers. Even nano-level ultra-fine powders are widely used in high-end fields such as high-end coatings, medicine, high-tech ceramics, microelectronics and information materials, advanced refractory and thermal insulation materials, fillers and new materials.
Ultra-fine powders are usually divided into micron, sub-micron, and nano-level powders. The powder with a particle size greater than 1μm is at the micron level, and the powder with a particle size of 0.1-1μm is at the sub-micron level, and the particle size is 0.001-0.1μm. The μm powder is of nanometer level. Due to the different levels of scientific research and technology in various countries, there is still no strict unified definition of ultrafine grinding so far. Generally, the grinding of ultrafine powders with a particle size of 0.1-10μm and the corresponding classification technology are called ultrafine grinding. Superfine grinding and superfine grades are difficult problems in powder deep processing, and they are also the key to powder technology.
The performance of ultra-fine powder is very different from that of ordinary particles. When the size of the particles reaches the sub-micron level, especially the nano-level, the atomic arrangement and electronic distribution structure and crystal structure of the surface have obvious changes compared with ordinary particles. In addition to the surface effects, small size effects, quantum effects and quantum tunneling effects that are different from ordinary particles, it will have excellent physical, chemical, surface and interface properties in some special occasions.
When the particle size is in the micron level, although its physical and chemical properties are not much different from the physical and chemical properties of ordinary particles, the specific surface area and surface energy of micron-level particles are large, and the surface and interface properties have undergone great changes. E.g:
- After ultrafine grinding, when medicines, foods, nutrition products and cosmetics reach the micron level, they are very easy to be absorbed by the human body or skin, and the efficacy is significantly improved;
- After the particles in the paint, paint, and dye reach the micron level, the surface activity is improved, the interface characteristics are improved, and the adhesion, uniformity and surface gloss after crushing are greatly improved;
- After the cement is superfinely pulverized, the surface activity of the particles is increased, and the strength is improved;
- As the particles are refined, the surface energy is improved, and the sintering temperature of ultra-fine powder ceramic or metal is greatly reduced.
If the physical and chemical properties of a single micron-sized ultrafine powder are not much different from those of ordinary particles, then the combination of a variety of ultrafine particles with different properties is different. When they are made into composite materials, Its properties are often completely different from raw materials, such as lower melting point, increased chemical activity, and increased catalytic effect.
Ultrafine grinding technology is extremely important for the development of modern high-tech new materials industry. In order to meet the requirements of related application fields for ultra-fine, narrow distribution and mass production of powder materials, the focus of future development of pulverization and classification technology will be It is superfine grinding and fine classification technology.