Research progress in water-based bitumen extraction from oil sands

As an unconventional oil resource,oil sands and its processing technology has attracted much attention in China in recent years.Water-based extraction processes are the most important method to recover bitumen from oil sands.Two key steps are involved in this process:bitumen liberation from the sand grains and bitumen aeration followed by flotation to form a bitumen-rich froth.Any factor that causes poor liberation or poor aeration will result in a poor bitumen recovery.With the use of the advanced analytical instrumentations,such as the atomic force microscope(AFM),the understanding for the bitumen extraction from oil sands is extended from the macroscopic scale to the molecular level.It is found that the wettability of solids and water chemistry play significant roles in the processability of oil sands.Mechanisms related to the bitumen extraction processes are discussed in detail.The procedures of recovering bitumen from oil sands in industry are also briefly described.