Environmental Engineering Reference
In-Depth Information
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Fig. 12.3
Changes in world steel production
and properties. In particular, various properties can be provided by adding different
alloying elements such as carbon. Further, the hardness and ductility can be easily
controlled by heat treatment- even for steel having the same composition. Hence,
it has been used for a long time as a fundamental material for cutlery and farming
tools, and is also used in various constructional roles; for rails, pipes and many ma-
chinery parts. It has another important feature—the ease of its oxidation, relatively
small environmental impact to human and ecological systems, and good recyclabil-
ity due to its strong magnetism.
Figure
12.3
shows the changes in the amount of global steel production. Global
annual steel production remained around 700-800 million t after the oil shocks of
1973 and 1979, but has recently started to increase rapidly. This is mainly due to
increasing production in emergent countries and especially in China where produc-
tion has drastically increased by 6.5 times from 120 million t in 2000 to 780 million
in 2013. With such an increase in steel production, the prices of iron ores and coking
coal, which is a major raw material for metallurgical coke, have rapidly increased
several-fold and have maintained higher levels to the present day. In particular, the
price of iron ore has increased rapidly, showing a peak in 2008 during the resources
'bubble period', and surpassing that peak since 2010 (see Fig.
12.4
). When such
changes in the resource price are compared to the changes in steel production over
the same period, a degree of correlation can be observed, suggesting that the re-
source prices are responding according to its supply-demand relationship.
