Apparatus for receiving particulate product, spreading the particles in a thin layer, and feeding them to a surface of an electrostatic separator, comprising a hopper with a slot discharge opening above a vibrating inclined distribution plate over which the particles are distributed and move to a lower edge where they fall into the feed end of a substantially vertical chute which is capable of discharging the particles at a selected velocity in a generally horizontal direction, the particles passing through the hopper discharge slot being controlled by an adjustable gate to provide uniform feed to the distribution plate and to control the feed rate into the chute, the chute being adjustable to control velocity of particles leaving the chute, and the direction of discharge from the chute, and a bypass conduit to selectively conduct particles directly from the hopper to a point of discharge which avoids the vibrating plate and the vertical chute.