Hydrodynamic and Flotation Kinetic Analysis of a Large Scale Mechanical Agitated Flotation Cell with the Typical Impeller and the Arc Impeller

The processing of low grade mineral ores using large scale flotation cells is obviously more advantageous than smaller-scale processing. Large-scale flotation cells have become increasingly important for effective volume scale-up. In this study, the latest and largest flotation cell in China, with an effective volume of 680 m(3), is considered. Hydrodynamics and flotation kinetics analyses are conducted using computational fluid dynamics (CFD) simulation. It is demonstrated that the flotation cell with a typical impeller produces suitable hydrodynamics for mineral particles based on analysis of the flow pattern, gas dispersion and solid suspension. The performance of the large-scale flotation cell is studied using hydrodynamic performance parameters. The variation of the performance parameters, such as the power number (N-p), the Froude number (F-r), the air flow number (N-a), and so on, with the flotation cell volumes, followed trends similar to that of previous cells of a different size, which were proven to be effective for engineering applications. To decrease the detachment of mineral particles, a new type of impeller, for which the impeller plate is a hyperbolic curve, viz. an arc impeller, was developed. Compared with the typical impeller, the arc impeller expands and lifts the low circulating flow, thereby shortening the transportation distance of the mineral particles. The data indicates that kinetic eddy dissipation plays a key role in determining the collision kernel and collision probability profile. The newly designed arc impeller leads to a higher collision probability than the typical impeller, resulting in better flotation performance. This research should aid in the optimization of the structure of the 680 m(3) flotation cell.