ULTRASONIC SEPARATION OF FINE PARTICULATES

DURING THE PAST DECADE THERE HAVE BEEN NUMEROUS ADVANCES IN SEPARATION TECHNOLOGY IN ORDER TO MEET THE NEEDS FOR PHYSICAL SEPARATION PROCESSES IN INDUSTRY AS WELL AS IN THE LABORATORY. OUR PRELIMINARY INVESTIGATIONS INDICATE THAT ACOUSTIC RADIATION FORCES HAVE THE POTENTIAL TO GIVE RISE TONEW SEPARATION TECHNIQUES. WE HAVE DEMONSTRATED THAT ACOUSTIC RADIATION AND OTHER ACOUSTIC FORCES GENERATED AT MODEST ENERGY LEVELS IN THE MHZ FREQUENCY RANGE ARE SUFFICIENTLY STRONG TO EFFECTIVELY MOVE AND CONCENTRATE SUSPENDED FINE PARTICLES IN AQUEOUS SYSTEMS. IN THIS PROPOSED SEPARATION TECHNIQUE THE FORCES CAUSING THE SEPARATION ARE ONLY EXERTED UPON THE PARTICLE AND NOT ON THESUSPENDING MEDIUM, AND SEPARATIONS CAN BE ACHIEVED WITHOUT THE PRESENCE OF APPARATUS IN THE FLUID TO BE PROCESSED. IN THIS PHASE I PROJECT WE WILL DETERMINE PARTICLE AND ULTRASONIC PARAMETERS NECESSARY TO ACHIEVE EFFECTIVE SEPARATION. IN PHASE II, FLOW-THROUGH SEPARATORS WILL BE CONSTRUCTED AND EVALUATED. THESE SEPARATORS WILL HAVE APPLICATION, FOR EXAMPLE, IN THE EFFICIENT REMOVAL OF PARTICULATE CONTAMINANTS IN CRITICAL FLUIDS USED IN SEMICONDUCTOR PROCESSING, AND THE MANUFACTURE OF PHARMACEUTICALS AND THIN-FILM ADHESIVES.