A calibration probe for level detection systems in flotation columns

CIM Bulletin, Vol. 83, No. 935, 1990

C. O. Gomez, A. Uribe-Salas, J.A. Finch, Department of Mining and Metallurgical Engineering, McGill University, Montreal, Quebec, and B.J. Huls, Metallurgical Technology Centre, Falconbridge Limited, Sudbury Operations, Falconbridge

Froth depth or interface level is an important control variable in column flotation which can influence both grade and recovery. A common method of locating the level is based on sensing the hydrostatic pressure at one or more points along the column. The level indicated can be in considerable error, largely because of variations in froth and collection zone bulk densities. A portable conductivity probe has been developed to detect the position of the interface from conductance measurements across the interface. The location of the interface corresponds to the position where a large change in conductance is observed, which is primarily a consequence of the difference in gas holdup between the collection and froth zone. This probe detects the position of the interface to an accuracy of ± 5 cm. The probe can be used while the column is in operation, which allows for on-line recalibration of the level detection system. Results obtained in its application in a pilot-scale column (0.91 m in diameter) are described.

Keywords: Mineral processing, Flotation columns, Conductivity probes.