Abstract: Disclosed is an injector (21) for use in an impact pulverizer (20) which reduces the size of particulate matter such as sand. An inlet chamber and frustum member (38) direct the particles through a bore (42) and into a outlet channel (49) in the barrel of the injector (48). An inlet (55) directs high velocity air tangentially into a manifold (57), creating a vacuum proximate the nozzle tip (67) which causes acceleration of the particles into the barrel (48). A threaded portion (54) allows the nozzle member (52) to be adjusted so as to vary the air flow characteristics for obtaining the maximum rate of production of the pulverized particles.