Centrifugal slurry pump impeller

A centrifugal slurry pump impeller including a back shroud and a front shroud each with opposed inner and outer faces and an outer peripheral edge and a central axis, a plurality of pumping vanes extending between the inner main faces of the back and front shroud, each pumping vane including opposed main side faces, a leading edge in the region of the central axis and a trailing edge in the region of the outer peripheral edges of the back and front shrouds with a passageway between adjacent pumping vanes, each passageway including a blended region between each of the main side faces of the pumping vanes and the inner faces of the front and back shrouds wherein a surface of the inner face of at least one of the front and back shrouds includes a raised portion located between the blended regions of adjacent pumping vanes.