Abstract: Fluid material having solids entrained therein is injected under high pressure through a nozzle disposed tangentially of a cylindrical housing. Groups of impactors are spaced circumferentially about the housing interior and include multiple rows with adjacent rows being staggered. The solid material strikes the impactors thereby reducing the size of the material. The fluid carries the solids circularly around the housing with the solids gaining speed between groups of impactors. The housing has an axially positioned discharge chute which is vertically disposed and adjustable in height. The mixture circulates through the housing in a vortex pattern, and exits through the axial discharge. The heavier solids are urged radially outward under centrifugal force and constantly strike the impactors until their size is reduced sufficiently to allow them to follow the mixture through the axial discharge.