Dynamic Simulation And Control Of Column Flotation Units

Column flotation is emerging as one of the most important new separation technologies of the decade. Attendant to this development is the need for a quantitative understanding of the dynamic characteristics of columns. An understanding of the many important sub-processes occurring in the cell makes possible the development of dynamic simulators for flotation columns which will aid in the design of control systems for dynamic and steady state optimization. This paper presents a dynamic model for the column flotation cell developed from a population balance point of view similar to that which has been successfully applied to conventional flotation cells. In particular, the mixing that occurs within the pulp is modeled with a distributed-volume, mixer-in-series model as an approximation to the axially dispersed plug flow transport that occurs in the cell. This simpler approach avoids the distributed transport model which often leads to mathematical intractability. Other phenomena dealt with are the attachment and detachment of particles from bubbles in the froth and pulp, the transport of water and the bubble volumes with the froth and pulp phases. Simulation of the flotation of an Illinois No. 6 coal in a pilot plant flotation column were performed to test control strategies.