Everything about Bitumen totally explained
Bitumen is a mixture of
organic liquids that are highly
viscous, black, sticky, entirely soluble in
carbon disulfide, and composed primarily of highly condensed
polycyclic aromatic hydrocarbons.
Naturally occurring or
crude bitumen is a sticky,
tar-like form of
petroleum which is so thick and heavy that it must be heated or diluted before it'll flow. At room temperature, it's much like cold
molasses.
Refined bitumen is the residual (bottom) fraction obtained by
fractional distillation of
crude oil. It is the heaviest fraction and the one with the highest boiling point, boiling at .
In
British English, the word '
asphalt' refers to a mixture of mineral aggregate and bitumen (or
tarmac in common parlance). The word 'tar' refers to the black viscous material obtained from the destructive distillation of
coal and is chemically distinct from bitumen. In
American English, bitumen is referred to as 'asphalt' or 'asphalt cement' in
engineering jargon. In
Australian English, bitumen is sometimes used as the generic term for road surfaces. In
Canadian English, the word bitumen is used to refer to the vast Canadian deposits of extremely heavy
crude oil, while asphalt is used for the
oil refinery product used to pave roads and manufacture
roof shingles.
Diluted bitumen (diluted with
naphtha to make it flow in pipelines) is known as
dilbit in the Canadian petroleum industry, while bitumen upgraded to
synthetic crude oil is known as
syncrude and syncrude blended with bitumen as
synbit.
Most bitumens contain
sulfur and several heavy metals such as
nickel,
vanadium,
lead,
chromium,
mercury and also
arsenic,
selenium, and other toxic elements. Bitumens can provide good preservation of plants and animal fossils.
Uses
Bitumen is primarily used for paving roads. Its other uses are for
bituminous waterproofing products, including the use of bitumen in the production of
roofing felt and for sealing flat roofs.
Naturally occurring crude bitumen is the prime feed stock for petroleum production from
tar sands currently under development in Alberta, Canada. Canada has most of the world's supply of natural bitumen, covering 140,000 square kilometres (an area larger than England), giving it the second largest proven
oil reserves in the world. The
Athabasca oil sands is the largest bitumen deposit in Canada and the only one accessible to
surface mining, although recent technological breakthroughs have resulted in deeper deposits becoming producible by
in-situ methods. Because of
oil price increases since 2003, upgrading bitumen to synthetic
crude oil has become highly profitable. As of 2005 Canadian crude bitumen production averaged about per day and was projected to rise to per day by 2020.
In the past, bitumen was used to waterproof
boats, and even as a coating for buildings with some additives. The Greek historian
Herodotus said hot bitumen was used as mortar in the walls of
Babylon. It is also possible that the city of
Carthage was easily burnt due to extensive use of bitumen in construction.
Vessels for the heating of bitumen or bituminous compounds are usually excluded from public liability insurance policies.
Bitumen was also used in early photographic technology. It was most notably used by
French scientist
Joseph Nicéphore Niépce in the first picture ever taken. The bitumen used in his experiments were smeared on
pewter plates and then exposed to light, thus making a black and white image.
Thin bitumen plates are sometimes used by computer enthusiasts for silencing computer cases or noisy computer parts such as the hard drive. Bitumen layers are baked onto the outside of high end dishwashers to provide sound insulation.
Bitumen alternatives
The world has become increasingly concerned over the
global climate change thought to be caused by
greenhouse gases, chief among them anthropogenic
carbon dioxide which is released into the atmosphere from burning carbon fuels. This has led to the introduction of bitumen alternatives that are more environmentally friendly and non toxic. Bitumen can now be made from non-petroleum based renewable resources such as sugar,
molasses and rice, corn and potato starches. Bitumen can also be made from waste material by
fractional distillation of used motor
oils, which is sometimes disposed by burning or dumping into land fills. Non-petroleum based bitumen binders can be made light-colored. Roads made with lighter-colored pitch absorb less heat from solar radiation, and become less hot than darker surfaces, reducing their contribution to the
urban heat island effect.
Geologic origin
Naturally occurring deposits of bitumen are formed from the remains of ancient, microscopic
algae and other once-living things. These organisms died and their remains were deposited in the mud on the bottom of the ocean or lake where they lived. Under the
heat and
pressure of burial deep in the earth, the remains were transformed into materials such as bitumen,
kerogen, or
petroleum.
As bitumens are also found in
meteorites and
Archean rocks it's possible that some bitumens are
primordial material formed during
accretion of the Earth and reworked by bacteria that consume hydrocarbons. Bitumens are associated with
lead-
zinc mineralizations in
Mississippi Valley type deposits.
Further Information
Get more info on 'Bitumen'.
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