Bitumen-air aggregates flow to froth layer: I. Method of analysis

A method of evaluation of the phase composition of aggregates floating to the froth layer inside a separation cell is presented. The method can be applied for evaluation of performance of different industrial separation cells and/or various areas of the cells. The amount of solids contained in the aggregate has been calculated on the basis of differences in rise velocities of the aggregates and unloaded air bubbles of identical dimensions because in flotation an air bubble acts as a carrier of ore particles. A novel method of evaluation of the mass of solids in the aggregate is presented and a new, more general model describing velocity of unloaded bubbles is introduced. The principle of the method is presented with an example of analysis of the flux of the bitumen-air aggregates to the froth layer. Size and rise velocity of the aggregates were determined by analyzing sequences of the grabbed video frames. It was found that in the experiments analyzed the average single aggregate had an equivalent diameter of 1.0±0.6 mm and contained ca. 8.6∗10−4 g of bitumen. Most of the bitumen was transported to the froth layer by the aggregates of dimensions ca. 1.5 mm. Contribution of the aggregates smaller than 1 mm was low, despite their significant population. Equivalent diameters of the bubble and of the bitumen contained in the aggregate were of a similar order of magnitude.