Size classification is a fundamental operation in powder processing. The technical group of classification and sieving is one of the oldest groups in APPIE, which started activities in 1973, 2 years after APPIE’s establishment.
Recently, with the development of application for nano-sized particles, there is the demand for classification of small cut size and fairly high precision. Especially, the classification with high precision in a wide range from 1 to 50 micron is needed for many industrial applications. Moreover, there has been considerable interest in the classification technology for nanoparticles with cut sizes from 20 to 500 nm. The aim of our activities is to study latest problems and information about those topics.
Current level of technology,trend and activities in future
Being small-scale, achievement of high power output and guaranty of safety are strongly requested in such high level technology fields as battery production and semi-conductor industry. Particularly, separation of fine particles with high accuracy is strongly demanded. In the production of electronic parts and material processing industry, the separation technology of fine particles at count level is required to separate sub-micron and single-micron ceramic particles which have strong adhesive and agglomerative properties. In the case of dry particles, the classification of the sub-micron range with high accuracy is important. The research has been carried out to increase separation performance of semi free vortex type cyclone separator and to promote particle dispersion without particle deposition on the separator wall.
In the case of wet particles, separation of particles of 20 nm to 500 nm diameter size by the use of the centrifugal method attracts attention. For the classification at the nano-level, the research has been done on the special water sieve making use of electrical potential. It is strongly required to separate fine particles under the condition of high density of slurry concentration.
The problem in the conventional sieve classification is how to prevent particles from depositing on the screen. Metal sieves with the surface coated and ultra sonic vibration have been proposed for this problem. Owing to improvement, the high separation performance of sieves is confirmed in practical process. However, much still remains to be done to develop new sieve methods capable to separate finer particles under the higher throughput.
|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|
|Organizer||HOSOKAWA MICRON CORPORATION||KISHIGE/Toshihide|
|KANSAI WIRE NETTING CO., LTD.||YOSHIDA/Yuichi|
|SEISHIN ENTERPRISE CO., LTD.||TAKAHASHI/Ryuji|
|TOKYO SCREEN CO., LTD.||OGITA/Yoshihiro|