ELECTROPHORETIC CHARACTERIZATION AND PROCESSING OF ASPHALT RIDGE AND SUNNYSIDE TAR SANDS

Batch hot water digestion-flotation experiments, using the Asphalt Ridge and Sunnyside tar sands from the Uinta Basin in Utah, were carried out at temperatures of 30-degrees, 60-degrees and 90-degrees-195-degrees-C in order to obtain fine mineral particles and tailings water necessary for the electrophoretic mobility investigation. The bitumen in all runs but one was prepared by toluene extraction of the tar sand. For both Asphalt Ridge and Sunnyside tar sands negative surface charges were observed for all particles and droplets in the pH range from 3 to 10. It was found that fine mineral particles were effectively floated with bitumen droplets, but at a slower rate. Therefore a shorter flotation time was found to produce a higher grade of bitumen concentrate. The comparable negative electrical charge for both bitumen droplets and mineral particles suggests that bitumen gravity separation should precede flotation. Thus flotation would be used as a scavenging operation for the recovery of finely dispersed bitumen and the smallest possible zeta potential for bitumen droplets is desired for most efficient flotation.