Detection and analysis of oscillations in a mineral flotation circuit

A novel mineral slurry assaying method combining visible and near-infrared reflectance spectroscopy and traditional X-ray fluorescence has recently been developed. The improved method is capable of high-frequency assaying of slurry grades in zinc and copper flotation, thus being able to reveal possible rapid oscillations in the grades. In this study, the new measurements are used to detect oscillations in a copper flotation circuit. In addition, a recursive extension of a data-based signal analysis method, singular spectrum analysis, is introduced and applied to process data measured from the flotation circuit. The aim of the study is to pinpoint and eliminate the cause of the oscillations on-line in order to improve the performance of the circuit. It is shown that the oscillations can effectively be detected by the proposed method and that the structural similarity between the oscillatory signal and the other process signals can be quantified in real time. & 2009 Elsevier Ltd. All rights reserved.