Apparatus and method for de-watering of slurries

A method of delivering an output flow of slurry to a tracking screen using a duct, the method comprising:

• delivering a flow of slurry to an inlet portion of the duct, wherein the inlet portion of the duct is connected to an outlet portion of the duct by a duct section, and wherein the flow of slurry comprises a flocculated solid suspended in a liquid;
• introducing a first flow of gas into the flow of slurry using a first aperture at a first height in the duct section, wherein the first aperture is configured to introduce the first flow of gas at a first gas feed rate;
• introducing a second flow of gas into the flow of slurry using a second aperture at a second height in the duct section that is greater than the first height, wherein the second aperture is smaller than the first aperture and introduces the second flow of gas at a second gas feed rate that is substantially the same as the first gas feed rate;
• introducing a third flow of gas into the flow of slurry using a third aperture at a third height in the duct section that is greater than the second height, wherein the third aperture is configured to introduce the third flow of gas at a third gas feed rate that is substantially the same as the first gas feed rate;
• delivering the internal flow of slurry to the outlet portion of the duct where gas bubbles produced by the first, second, and third flows break the surface of the slurry to produce the output flow of slurry comprising the flocculated solid suspended in the liquid;
• and
• delivering the output flow of slurry to the tracking screen to separate at least a portion of the flocculated solid from the liquid.