Metso Corp, Finland

Abstract

Turbulence is an important factor that affects flotation performance, which needs to be incorporated into flotation models. However, the measurement of turbulence in industrial flotation cells is difficult because of the highly abrasive and aggressive slurry environment. This has made the development and validation of models incorporating turbulence difficult. The development of a measurement methodology based on the piezoelectric vibration sensor (PVS) has enabled the measurement of kinetic energy fluctuation in flotation cells. In the study presented in this paper, the PVS was first applied to a sugary water-air two phase mixture in a 3 m3 pilot flotation cell, and then to a Metso RCS 3 m3 flotation test rig with magnetite/silica slurry and air, to collect turbulence data. An orthogonal experimental design was used for both sets of tests, with different impeller speeds, air flow rates and cell level (aspect ratio) as input hydrodynamic parameters. From the measurement data collected in the two cells, the volume of the turbulence zone could be modelled; from this, the turbulence distribution in the flotation cells could be predicted. The models were validated by comparing the predicted with the experimental results.