Influence of flotation cell hydrodynamics on the flotation kinetics and scale up, Part 1: Hydrodynamic parameter measurements and ore property determination

Abstract

Developing practical measurement methodologies to characterise hydrodynamic conditions of flotation cells of any size, and the provision of useful data for flotation modelling, are a challenge. In this study, several measurement instruments such as a power meter, hot-wire anemometer, bubble sizer, air flow meter and viscometer were used to characterise the hydrodynamic condition inside two different flotation cells (5L and 60L) making it possible to compare the hydrodynamic conditions of a 5L (lab scale) cell with a 60L (pilot scale) flotation cell. As a result, power input, energy dissipation rate, turbulent kinetic energy, bubble size and air flow parameters were obtained for 12 different hydrodynamic conditions in the cells.It has been assumed that P (ore floatability) in the AMIRA P9 model remains constant over a wide range of bubble surface area flux (Sb) regardless of the amount of power introduced into a flotation cell. Therefore, increasing the impeller speed in the cell does not have any effect on the P value if P is the true ore property. However, flotation test work was conducted in the above mentioned different hydrodynamic conditions in both cells, and shows that by increasing the power input the P value is also increased, especially for particle size classes below 75μm in both cells. P, in its current form, cannot therefore be the true ore property and is influenced by cell hydrodynamics. It should be mentioned that the current AMIRA P9 model still remains a useful model to simulate a plant operation under some circumstances not far from its original design state. However, in order to improve the scale up capability from lab scale flotation tests, it is necessary to incorporate the measured hydrodynamic parameters into the AMIRA P9 model.