Column flotation

Abstract

In the froth flotation of ore in a column, the froth/pulp interface level and the efficiency of the froth washing operation are controlled by determining a profile of temperatures measured in the froth layer and slurry below the interface. Temperatures are measured with temperature sensing elements immersed in the froth layer and extending to below the interface level. The measured profile is compared with a target profile and deviations are corrected by changing the tailings flowrate or the washwater flowrate to return a measured profile to the target profile. An inflection point in the profile occurs at the interface level. The inflection point in a measured profile is compared with a level set point, and a deviation from set point value is corrected by increasing or decreasing the flow of tailings whereby the interface level returns to its set point. The washwater rate is controlled by measuring the slope or the position of a measured temperature profile and comparing the measured slope or position with the slope or position of a target profile, i.e. slope or position set point, and a deviation from set point value is corrected by increasing or decreasing the flow of washwater. The washwater distribution is controlled by measuring the concentrate temperature at a plurality of points at the concentrate overflow, comparing each measured temperature with a set point value, and a deviation from set point value is corrected by adjusting the distribution of washwater. A programmed computer may be used for calculating profiles, comparing measured values with set point values and sending a signal for controlling washwater rate or distribution or tailings flow when the deviation of measured values exceeds set point values by a predetermined amount.