Recovery of Bitumen from Utah Tar Sands Using Ionic Liquids

Hot or warm water processes are used to extract bitumen from Canadian oil or tar sands. The application of these methods to the processing of tar sand deposits found in the Western United States, notably Utah, has not been commercially successful, however, because of the consolidated nature of the deposits and the high viscosity of the bitumen. It is demonstrated here that a previously developed method employing ionic liquids (ILs) together with a nonpolar solvent such as toluene can effect a separation at ambient temperatures (∼25 °C), although with greater difficulty than Canadian oil sands. Essentially, a multiphase system consisting of a sand and clay slurry, an ionic liquid layer, and an organic layer containing the bitumen can be formed by simply mixing the components. More than 90% of the bitumen is released from the sand, but only in successive extractions. Water is not used in this stage of the separation, but relatively small amounts are used to separate entrained IL from the sand and clays.