DRY MECHANICAL DISPERSION OF SUBMICRON PARTICLES

Concerning the use of air classifiers with cut sizes in the micron ran ge and lower, it is necessary to disperse the feed material properly i n an air flow to avoid agglomerates larger than the desired cut size. Commonly used dispersing devices such as injectors use large amounts o f air. To reduce the size and costs of the subsequent air classifiers, two new types of dispersing systems were developed, one design being related to a brush feeder and the other to a pin mill. Both apply mech anical rather than fluid mechanical forces in the dispersion process. The brush disperser achieves the same size distributions as the pin mi ll disperser with much less machinery. Its properties as a feeding and dispersing system are shown and its ability to disperse particles in the submicron range is confirmed by two independent particle size anal ysis systems: a new diffraction spectrometer and an impactor.