A mass transfer approach to flotation column design

Flotation equipment design is an area of reactor engineering that has not attracted much research interest in chemical engineering. The commercial success of flotation remains a triumph of enlightened know how over inadequate know why as key design and scale-up parameters (e.g. column height) continue to be dictated by such non-process considerations as crane rail and building heights (Ounpuu and Tremblay, 1991). The shortcomings in the present approach to flotation column design and scale-up are discussed. It is shown that the use of first order kinetic expression in flotation column design and scale-up is not correct insofar as the recovery and order of the process are concentration dependent. By using analogy with interface mass transfer, a new approach to flotation column design is presented. Using literature data, it is shown that only a short recovery zone is required for particles made selectively hydrophobic. Recent experimental data from 1.2m flotation column (Ounpuu and Tremblay, 1991) and those of others as well (Wheeler, 1984; Bensely 1985; Jameson, 1988; Reddy 1988) confirm this observation.