Future (and Present) Trends in Flotation Circuit Design
The conventional approach to flotation circuit design has undergone a number of developments in the past decade. The need to maximise recovery and value when processing low-grade orebodies at high throughput presents a number of challenges. For example, improving both fine and coarse particle recovery, footprint and layout constraints, as well as managing CAPEX/OPEX, are driving innovations in cell selection, design, sizing and duty. Economies of scale have traditionally been achieved by the installation of large mechanical cells with volumes over 600 m3 to meet residence time requirements for high-capacity plants. However, in these large cells performance and flotation efficiency are compromised. Reduced mixing, turbulence, dead zones, greater froth travel distance to the concentrate launder plus increased chance of particle detachment back into the pulp phase limit their effectiveness. Hatch has completed concept studies, feasibility and detailed engineering designs for several flotation technologies which are setting new standards for circuit design and performance. This paper describes the piloting, modelling, and engineering required to install the largest Jameson Cell developed for a rougher-scalping duty, as well as evaluation of Jameson Cells not only in cleaner stages (their traditional use) but also in pre-flotation and scalping duties. The paper also covers engineering design of coarse particle flotation circuits, including experience with conceptual studies, test work and detailed design to apply the Eriez HydroFloat™ to coarse tailings scavenging. Finally, the evaluation and application of small footprint and fast flotation kinetics cells such as Eriez StackCell®s, Woodgrove Staged Flotation Reactor (SFR) and Direct Flotation Reactor (DFR) is discussed.