A method of visualization and characterization of aggregate flow inside a separation vessel, Part 2. Composition of the bitumen-air aggregates

A method for the evaluation of composition of a bitumen-air aggregate float ing in a separation vessel to the froth layer is presented. The mass of bit umen contained in the bitumen-air aggregate was determined on the basis of measured aggregate size and rise velocity inside the separation vessel. Rel ationships describing the velocity of unloaded, contaminated and uncontamin ated bubbles were used as a 'reference state' that was needed to evaluate t he composition of the bitumen-air aggregate, They were used to illustrate h ow a choice of the 'reference state' can affect the calculated mass of bitu men in an aggregate. It was found that the mass of bitumen contained in a b itumen-air aggregate was in the range of 10(-6) to 10(-4) g depending on th e aggregate dimension and velocity relationship used. The evaluated equival ent diameter of the aggregates was within the range of 0.2-1.2 mm. The appr oach presented here can be generalized to other gas-solids flotation system s. (C) 1999 Elsevier Science B.V. All rights reserved.