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Coal is a complex combination of materials, and the
combination can greatly differ from one formation or deposit to
another. These differences result from:
- the varying types of vegetation from which the coal
originated;
- the depths of burial, and the temperatures and pressures
at those depths; as well as
- the length of time the coal has been forming in the
deposit.
The varying amount of minerals in a coal deposit may also
have a significant effect on its properties and classification.
In addition to carbon, coals contain hydrogen, oxygen, nitrogen
and varying amounts of sulphur. High-rank coals are high in
carbon and heat value, but low in hydrogen and oxygen. Low-rank
coals are low in carbon but high in hydrogen and oxygen content.
Anthracite is the highest carbon content, followed by
bituminous, sub-bituminous and lignite coal, which has the
lowest carbon content
Anthracite
Anthracitea
nearly pure form of carbonis the highest ranked coal. It high
carbon content allows anthracite to burn hot and long! When
burning anthracite, as opposed to other coals, there is a
maximum amount of heat production, with minimum ash. The heat
generation is intense enough to melt stoves
Why isnt anthracite used to make steel? Its high carbon
rating would seem to make it ideal. Theres a flaw in the
picture: its too dense. The solution: heat bituminous coal to
more than 1000° Celsius while starving its access to oxygen. The
process, known as "coking," burns off the volatile organic
compounds and leaves "coke," a porous, nearly pure form of
carbona product ideal for the making of steel.
Anthracite is no longer mined in Canada. Natural gas and
electricity have replaced it for in-home use.
Bituminous Coal
Bituminous
coal is versatile. It was once used to heat homes, power steam
engines, create steel and generate electricity. Today,
bituminous coal is still the fuel of choice for the latter two
uses.
Almost all of Canadas coal exports are bituminousa product
thats mined in the Rocky Mountains of Elk Valley, BC.
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