A level detection probe for industrial flotation columns

ABSTRACT The most common method for detecting froth depth (level of the interface between the bubbling and froth zones) in a flotation column is by measuring the hydrostatic pressure below the interface. The accuracy of this method is affected by variations in the operational variables and in the characteristics of the stream being processed. The error can be substantial. A new approach has been developed based on the different conductances in the bubbling and froth zones which are a consequence of their different gas holdups. The technique has been successfully used in laboratory and pilot-scale (0.91 m diameter) columns giving accuracies better than ± 5 cm. Based on this experience, an industrial probe has been designed and built for use in production columns. This paper includes a description of the probe and results obtained during plant testing.