Crown aspirators efficiently separate heavy and light materials, using a combination of gravity, impact rods, and air. Product is introduced into the integral feeder, which controls and distributes the feed across the entire cross-sectional area of the aspirator, and also provides an air seal. Material free falls through a series of specially designed and positioned impact rods, breaking any bonds between the product and liftings. Heavier phase material is discharged from the bottom of the aspirator. Lighter material is airlifted to the top of the aspirator by the counter-current and subjected to a final rectification to separate any entrained heavy phase material before ejection from the system. Standard design includes inlet and outlet connections for a completely closed-loop air system.