Abstract

The separation of oil or bitumen from a surface of a substrate covered with same is effected by first dissolving the oil or bitumen in a solvent to form a solution thereof. A liquid which does not dissolve the oil or bitumen, is non-miscible with the solvent and has substantially higher surface wetting properties than the solvent on subtstrate is then intimately contacted with the surface of the substrate; the solvent and liquid are capable of forming in the presence of the oil or bitumen an interfacial membrane-like material which is impermeable thereto. The intimate contacting of this liquid with the surface of the substrate causes the membrane-like material to form at the surface of the substrate while the liquid wets the surface and spreads thereover, the liquid displacing the membrane-like material away from the surface as it is being formed thereacross to thereby separate the solution from the surface and cover the surface with a layer of the liquid; the membrance-like material acts as a barrier to maintain the oil or bitumen in the solution and to prevent passage of same into the layer of liquid. The method of the invention avoids the use of surfactants and the formation of emulsions, and thus the problems associated therewith. The invention finds a particular application in the recovery of oil and bitumen from bitumen covered tar sands and oil sands from oil wells.