Metallurgical testing and CFD simulation of StackCell® SC-50 high-intensity flotation machine

An extensive field test was conducted by Rio Tinto and Eriez to evaluate the operability and metallurgical performance of a StackCell® SC-50 high-intensity flotation machine for recovery of copper and molybdenum from flotation tailings. The field test of the 15-m3 StackCell flotation cell was conducted at Rio Tinto’s state-of-the-art tailings recovery demonstration plant located within Kennecott Utah Copper’s tailings facility. The metallurgical results demonstrate that the StackCell technology provides a unique solution for recovering metal values from tailings, with excellent selectivity and an order of magnitude increase in flotation kinetics compared to conventional mechanical flotation machines. The metallurgical advantages of the StackCell are particularly pronounced for treating fine tailings, with upgrade ratios >25 achieved at average copper and molybdenum recoveries of 20% and 28%, respectively, within approximately one minute of flotation residence time. Computational fluid dynamics (CFD) simulations were conducted to provide a fundamental explanation of the findings from metallurgical field measurements. The simulations show that maximum levels of turbulent dissipation rates in the StackCell contacting chamber are nearly 5 times that of rotor/stator mechanisms in conventional mechanical flotation machines. Furthermore, the high levels of turbulent dissipation rates in the contacting chamber are favorable for high collisions and attachments rates of fine particles with air bubbles.