US Patent 7334689 Overflow launder

An overflow launder for a separation cell where particles are fluidiZEd and rise to the top of the cell, has a primary trough (1) surrounding the rim of the cell (2), and an array of secondary troughs (4) extending across the fluid surface from the side (5) of the rim to the opposite side (6). FluidiZed particles can report directly to the secondary troughs (4) without travelling across the surface of the cell, reducing the incidence configurations with radial secondary troughs and external and/or internal primary troughs are also described.