Abstract
Size-selective procedures were developed for the preparation of fiber fractions of uniform size of chrysotile, crocidolite, amosite and glass. The raw material was first ground to a suitable fineness, then prescreened in a vibrating bed aerosol generator and finally suspended in liquids by ultrasonic agitation. Size-separation was then achieved by slow sedimentation. In addition, fiber fractions of exceedingly long-fibers were prepared by utilizing a vibrating sieve in the gas phase or in liquids.