BITUMEN-SAND INTERACTION IN OIL SAND PROCESSING

Bitumen-sand interaction was studied as a function of pH, particle siz e. temperature and solvent addition to bitumen. Sand particles can be easily detached from the bitumen surface at pH > 6, At pH < 6. strong attachment between bitumen and sand is observed. The bitumen-sand inte raction is also particle-size dependent: the finer the particles, the stronger the attachment. The detachment of coarse particles from bitum en can be achieved by increasing the alkalinity of the solution, but n ot for fine particles. indicating that the particle size is one of the critical factors affecting liberation of bitumen from sand. Increasin g temperature has two effects: it is not only reduces the viscosity to facilitate bitumen liberation, but also increases the electrostatic r epulsion between sand and bitumen. This is confirmed by the DLVO theor y and is in agreement with the batch extraction results on real oil sa nds.