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

A method of evaluation of the phase composition of aggregates floating to t he froth layer inside a separation cell is presented. The method can be app lied for evaluation of performance of different industrial separation cells and/or various areas of the cells. The amount of solids contained in the a ggregate has been calculated on the basis of differences in rise velocities of the aggregates and unloaded air bubbles of identical dimensions because in potation an air bubble acts as a carrier of ore particles. A novel meth od of evaluation of the mass of solids in the aggregate is presented and a new, more general model describing velocity of unloaded bubbles is introduc ed. 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 ve locity of the aggregates were determined by analyzing sequences of the grab bed 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 fro th layer by the aggregates of dimensions ca. 1.5 mm. Contribution of the ag gregates smaller than 1 mm was low, despite their significant population. E quivalent diameters of the bubble and of the bitumen contained in the aggre gate were of a similar order of magnitude. (C) 2000 Elsevier Science Ltd. A ll rights reserved.