Apparatus for flotation

Claim 1

In a flotation cell including means for dispensing a gas in a liquid, such means comprising a liquid propulsion jet nozzle arranged axially inside a gas-providing tube, the nozzle and tube ending in a funnel-shaped mixing chamber, the mixing chamber being formed by a funnel-shaped casing containing a conical deflecting element arranged in line with the axis of the propulsion jet, thereby forming an annular passage, the improvement wherein the funnel has a concave curvature over its entire length and the angle of the conical deflecting element is between 60° and 120° such that the annular passage has a first zone of decreasing cross-section followed by a second zone of increasing cross-section in the flow direction, wherein the ratio of diameter of the conical deflecting element (d 1 ) to the diameter of the jet nozzle (d) is more than 3, and wherein the jet nozzle diameter (d) is at least 10 mm and the width of the annular passage at the increasing cross-section (h) is at least 5 mm, whereby the nozzle acts as a confuser in the first zone and a diffuser in the second zone to obtain high self-aspirated gas throughputs.