Mixing in flotation columns. Part III. Internal circulation (original) (raw)

A mixed zones-in-series model, allowing for backflow between adjacent zones, has been used to describe the flow structure established in the collection zone of a flotation column. Experimental residence time distribution data were used to quantify the baclfllow parameter (2), using the tracer breakthrough time," this parameter was shown to depend essentially only on the supeoqcial liquid velocity and the column diameter (d c) and the following correlation was obtained : /l = 0.347 exp(O.303dc) uL-(O'S30+O'O348dO. The circulation velocity of the additional circulatory flow induced by the gas stream was also determined," the experimental results were well corroborated by predictions using theoretical axial velocity models.