A NEW SIZING TECHNIQUE FOR FINE POWDERS DISPERSED IN AIR

We have recently developed a sizing technique for fine powders by comb ining a boiling method with a DMA (differential mobility analyzer)-CNC (condensation nucleus counter) system. In the boiling method, particl e aggregates are broken up into their primary particles, and then the particle size distribution is accurately measured by the DMA-CNC syste m. In the present work, we have applied this method to the particle si ze measurement of several kinds of fine powders including tightly coag ulated particles and nonspherical particles (needlelike and flakelike particles). The results are in good agreement with those obtained by e lectron microscope and centrifugal sedimentation methods. (C) 1998 Els evier Science S.A. All rights reserved.