Alberta's bitumen deposits were called tar sands
but are now referred to as oil sands. Bitumen is a
thick, sticky form of crude oil, it is so heavy and
viscous that it will not flow unless heated or
diluted with lighter hydrocarbons. Heavy oil and
bitumen consist of large hydrocarbon molecules,
which contain proportionately more carbon atoms than
hydrogen atoms.
Once the oil has been removed from the sand it
has to be treated and processed. Ultimately, heavy
oil and bitumen are used to make the same petroleum
products as conventional forms of crude oil;
however, more processing is required. Separation
continues at the plant where the bitumen forms a
thick froth at the top of the separation vessel and
the sand settles out to the bottom. Material, which
includes water, from the middle part of the vessel
is further processed to remove more bitumen. The
water is then recycled and the sand is used in mine site
reclamation. Froth is treated using inclined plate
settlers or centrifuges to remove water and solids.
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