The Technical Group of Classification and Sieving is one of the oldest technical groups in APPIE. Recently, there is the demand for classification of small cut size in response to application of nanoparticles. In particular, high-precision classification is required for a wide size range from 1 to 50 micron meter. Moreover, there is considerable interest in the classification technology for nanoparticles with cut sizes from 20 to 500 nm. This group makes a survey and collect information regarding these requirements.
Current level of technology,trend and activities in future
- Downsizing, high power, large capacity and safety are required recently in high-tech areas such as battery and semiconductor. As the result, needs of size reduction of raw powders, micro-scale separation with high accuracy and prevention of metal contamination are increasing.
- Particularly in the case of multi-layer ceramic condenser, number-base classification which separates cohesive ceramic and metal powders with the size from sub-micron to single-micron is strongly demanded.
- The important issue in dry classification is accurate control of classification of sub-micron powders. Research is made on semi free vortex classifiers such as cyclone separators. It is studied how to enhance separation efficiency and how to prevent particles from adhering to the wall. Compact cyclone separators with high performance are commercialized as vacuum cleaners for home use. Further grade-up is expected for these machines.
- In wet classification, classification with cut-size from 20 nm to 500 nm draw the highest attention. The accurate water sieve (sedimentation method) making use of electric field is studied in the nano-size classification. Development of classifiers which keep high accuracy even in large particle concentration is required.
- Surface treatment of mesh and use of super-sonic is proposed to enable sieve classification to be applied to cohesive and adhesive powders. These methods are confirmed to be effective for practical use. What is required in the sieve is durability of mesh and applicability of sieve for finer powders with large capacity.
|Coordinator||Hiroshima University, Graduate School of Engineering, Department of Chemical Engineering||YOSHIDA/Hideto|
|Representative Organizer||NISSHIN ENGINEERING INC.||AKIYAMA/Satoshi|
|Vice Representative Organizer||KOEI SANGYO CO., LTD.||SATO/Kazuhiko|
|HOSOKAWA MICRON CORPORATION||KISHIGE/Toshihide|
|KANSAI WIRE NETTING CO., LTD.||YOSHIDA/Yuichi|
|NISSHIN SEIFUN GROUP INC.||JIKIHARA/Kenji|
|SEISHIN ENTERPRISE CO., LTD.||TAKAHASHI/Ryuji|
|TOKYO SCREEN CO., LTD.||OGITA/Yoshihiro|