INTERPRETATION OF THE EFFECT OF FROTH STRUCTURE ON THE PERFORMANCE OFFROTH FLOTATION USING IMAGE-ANALYSIS

The recovery and grades of a coal flotation concentrate are significan tly dependant on the water content of the overflowing froth. The drain age of water from the froth is associated with the coalescence and bur sting of bubbles in the froth. This work was undertaken to investigate the possibility of regulating the performance of a flotation cell by using Image Analysis to define a desired bubble size in the concentrat e, and subsequently to use measured deviations to control bubble coale scence by the compensating addition of surfactants. The image analysis was done on a transputer-enhanced Micro Var computer off-line, using video images of experimental semi-batch runs. Individual runs were don e using a single surfactant which had to act both as a frother and col lector, two surfactants 2-ethyl hexanol and Triton X-405 being used. D ata from the image analysis was interpreted together with experimental measurements of particle and water recoveries in terms of a previousl y formulated froth kinetic model. Correlation of the point rates of ov erflow of dry-mineral-matter-free (dmmf) coal in terms of the model pr oduced physically plausible parameters. (C) 1998 Elsevier Science S.A. All rights reserved.