Prediction of complex sulfide flotation performances by a combined 3D fractal and colour analysis of the froths

It has long been accepted that froth appearance is a good qualitative indicator of the performance of the flotation process. This paper investigates the possibility of the froth surface 3D reconstruction that can provide significant information about the process efficiency. The froth 3D model was realised performing a preliminary watershed segmentation of the image, a further morphological and morphometrical analysis and finally building a series of “domes” founded on the equivalent ellipses of the identified bubbles. Height and curvature of the resulting ellipsoids were defined analysing light intensity distribution inside each identified domain (bubble). The technique developed generates an elevation model of the surface that is then analysed by a fractal method. The froth surface showed two fractal dimensions that can be used, along with froth colour parameters, to forecast mineral grades of the froths.