Ultrafine powder classification technology and typical equipment

Ultrafine powders are not only the foundation for structural materials but also have unique functions. They are essential for fine ceramics, electronic components, bioengineering, new printing materials, high-quality refractories, and fine chemicals.
With the growing use of ultrafine powders in modern industries, ultrafine powder classification technology has become increasingly important in powder processing, optimizing product quality, efficiency, and energy consumption.

The significance of classification

During grinding, only a portion of the powder often meets the required particle size. If you don’t separate the qualified products in time and re-grind them with unqualified ones, you will waste energy and cause over-grinding of some products.

As particles are refined, grinding and agglomeration occur, worsening the process as particles clump together. To solve this, classify products during ultrafine powder preparation. This controls the particle size within the desired range and separates products that meet the size requirement. Meanwhile, you return coarse particles for re-grinding, which improves efficiency and reduces energy consumption.

As the required powder fineness increases and production rises, classification technology becomes more challenging. Powder classification has become a key factor limiting powder technology development. It is one of the most important fundamental technologies in powder processing. Therefore, research on ultrafine powder classification technology and equipment is essential.

Principle of classification

In a broad sense, classification refers to dividing particles into different parts based on properties such as particle size, density, color, shape, chemical composition, magnetism, and radioactivity. In a narrow sense, classification is based on the movement of particles with different sizes under the influence of centrifugal force, gravity, and inertial force in a medium (usually air or water), leading to distinct trajectories and thus sorting particles by size.

Classification equipment

The air classifier is a classification device, forming a system with a cyclone separator, dust collector, and exhaust fan. Under the fan’s suction, the material enters the classifier through the lower feed inlet and moves upward. In the classification area, the high-speed airflow and centrifugal force from the rotating classifier wheel separate coarse and fine particles. Fine particles meeting the size requirement pass through the wheel gap and enter the cyclone separator or dust collector for collection. Coarse particles, carrying some fine particles, collide with the wall and lose speed, descending along the cylinder wall. At the secondary air inlet, strong air washing further separates coarse and fine particles. Fine particles rise for secondary classification, while coarse particles exit through the discharge outlet.

It can be paired with ball mills, mills, air jet mills, or used alone. The system widely applies for fine classification of powders such as calcined kaolin, talc, heavy calcium, barytes, mica, alumina, zirconia, magnesium oxide, silicon carbide, and lithium cobaltate.

Conclusion

In conclusion, ultrafine powder classification plays a crucial role in enhancing grinding efficiency and product quality. By effectively separating particles based on size, it helps minimize energy consumption and prevent over-grinding. As industries continue to demand finer powders with precise specifications, mastering classification techniques will remain vital for optimizing production processes and ensuring the performance of end products.

Epic powder

Epic Powder, 20+ years of work experience in the ultrafine powder industry. Actively promote the future development of ultra-fine powder, focusing on crushing,grinding,classifying and modification process of ultra-fine powder.  Contact us for a free consultation and customized solutions! Our expert team is dedicated to providing high-quality products and services to maximize the value of your powder processing. Epic Powder—Your Trusted Powder Processing Expert !