Recovery of Bitumen from Oil or Tar Sands Using Ionic Liquids

TLDR

Extracting bitumen from oil sands is costly, energy‑intensive, and water‑heavy, requiring roughly two tons of sand per barrel of oil and posing significant environmental challenges. The authors create a multiphase system comprising a sand‑clay slurry, an ionic‑liquid layer, and an organic bitumen layer by simply mixing the components at 25–55 °C. Using ionic liquids and organic solvents, the process releases essentially all bitumen without water‑based separation, and the recyclable IL and water reduce the environmental impact of current extraction methods.

Abstract

The extraction and separation of bitumen from oil sands for the purpose of processing fuels is relatively expensive and poses several environmental challenges. Roughly two tons of oil sands are required to produce a barrel of oil, and the separation of the bitumen from sand and clay requires significant amounts of energy and the use of large quantities of water. It is shown here that bitumen in a sample of Canadian tar sands can be recovered using ionic liquids (ILs) and organic solvents. 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 at somewhat elevated (∼55 °C) or ambient temperatures (∼25 °C). Essentially all of the bitumen is released from the sand. 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. Because both the IL and water can be recycled through the system and used repeatedly, this process has the potential for ameliorating many of the environmental problems associated with current extraction methods.