A coarse-fraction concentration method used in milling pebble phosphate that is based on flowing reagentized feed over a submerged sloping, stationary screen. Agglomerated phosphate particles float on top of the screen and are recovered at the lower end. Sand particles pass through the screen and are removed as a tailings fraction. Each screen section is approx. 3 ft (0.9 m) wide by 4 ft (1.2 m) long and treats 2 to 3 st/h (1.8 to 2.7 t/h) of feed.