5. The sand-and-water slurry is dumped into tanks with hot water, where it separates into three layers: sand, bitumen froth (impure bitumen), and a middle layer that is further treated to extract bitumen. Bitumen froth is also treated to remove impurities. [Click here to view image.]
6. Oil companies create ponds in which to dump millions of cubic meters of the sandy, toxic by-product of oil-sand processing. These “tailings ponds” are characterized by salt and acids. Here, a worker installs a scarecrow to keep birds away. [Click here to view image.]
7. Bitumen is a viscous mixture of long hydrocarbon chains–strings of as many as thousands of carbon atoms bonded to hydrogen atoms. These molecules must be “upgraded” to shorter molecules before they can be refined into petroleum products.
Purified bitumen is heated to break its long hydrocarbon chains into lighter molecules, such as naphtha, that can be refined. This process is called coking and takes place in large towers. The high-carbon by-product of the process, called coke, in turn fuels the coking furnaces. Distillation and a hydrogenation process are the final steps. [Click here to view image.]
8. The extensive processing of oil sand generates “sweet” crude oil, so called because of its low levels of sulfur and other impurities. Crude oil can be refined into gasoline of different grades and chemicals for making plastics. [Click here to view image.]
Photo 1: Lara Solt/Dallas Morning News/Corbis; photo 2: Greg Smith/Corbis; inset: courtesy of Suncor Energy, Inc.; photo 3: Courtesy of Petro-Canada; photo 4: Courtesy of Suncor Energy, Inc.; photo 5: Hans-Juergen Burkard/Bilderberg; inset: courtesy of Suncrude Canada Ltd.; photo 6: Hans-Juergen Burkard/Bilderberg; photo 7: Courtesy of Syncrude Canada Ltd.; photo 8: Courtesy of Syncrude Canada Ltd.